Federal Register, Volume 90 Issue 89 (Friday, May 9, 2025)

[Federal Register Volume 90, Number 89 (Friday, May 9, 2025)]
[Proposed Rules]
[Pages 19858-20077]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-07780]

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Vol. 90

Friday,

No. 89

May 9, 2025

Part III

Department of Commerce

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National Oceanic and Atmospheric Administration

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50 CFR Part 218

Takes of Marine Mammals Incidental to Specified Activities; Taking
Marine Mammals Incidental to Military Readiness Activities in the
Atlantic Fleet Training and Testing Study Area; Proposed Rule

Federal Register / Vol. 90, No. 89 / Friday, May 9, 2025 / Proposed
Rules

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 218

[Docket No. 250430-0074]
RIN 0648-BN17

Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Military Readiness Activities in
the Atlantic Fleet Training and Testing Study Area

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.

ACTION: Proposed rule; proposed letters of authorization; request for
comments.

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SUMMARY: NMFS has received a request from the U.S. Department of the
Navy (including the U.S. Navy and the U.S. Marine Corps (Navy)) and on
behalf of the U.S. Coast Guard (Coast Guard; hereafter, Navy and Coast
Guard are collectively referred to as Action Proponents) for Incidental
Take Regulations (ITR) and three associated Letters of Authorization
(LOAs) pursuant to the Marine Mammal Protection Act (MMPA). The
requested regulations would govern the authorization of take of marine
mammals incidental to training and testing activities conducted in the
Atlantic Fleet Training and Testing (AFTT) Study Area over the course
of seven years from November 2025 through November 2032. NMFS requests
comments on this proposed rule. NMFS will consider public comments
prior to making any final decision on the promulgation of the requested
ITR and issuance of the LOAs; agency responses to public comments will
be summarized in the final rule, if issued. The Action Proponents'
activities are considered military readiness activities pursuant to the
MMPA, as amended by the National Defense Authorization Act for Fiscal
Year 2004 (2004 NDAA).

DATES: Comments and information must be received no later than June 9,
2025.

ADDRESSES: A plain language summary of this proposed rule is available
at https://www.regulations.gov/docket/NOAA-NMFS-2024-0115. You may
submit comments on this document, identified by NOAA-NMFS-2024-0115, by
any of the following methods:
Electronic Submission: Submit all electronic public
comments via the Federal e-Rulemaking Portal. Visit https://www.regulations.gov and type NOAA-NMFS-2024-0115 in the Search box.
Click on the ``Comment'' icon, complete the required fields, and enter
or attach your comments.
Mail: Submit written comments to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service, 1315 East-West Highway, Silver
Spring, MD 20910-3225.
Fax: (301) 713-0376; Attn: Jolie Harrison.
Instructions: Comments sent by any other method, to any other
address or individual, or received after the end of the comment period,
may not be considered by NMFS. All comments received are a part of the
public record and will generally be posted for public viewing on
https://www.regulations.gov without change. All personal identifying
information (e.g., name, address, etc.), confidential business
information, or otherwise sensitive information submitted voluntarily
by the sender will be publicly accessible. NMFS will accept anonymous
comments (enter ``N/A'' in the required fields if you wish to remain
anonymous). Attachments to electronic comments will be accepted in
Microsoft Word, Excel, or Adobe PDF file formats only.
A copy of the Action Proponents' Incidental Take Authorization
(ITA) application and supporting documents, as well as a list of the
references cited in this document, may be obtained online at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities. In case of problems
accessing these documents, please call the contact listed below (see
FOR FURTHER INFORMATION CONTACT).

FOR FURTHER INFORMATION CONTACT: Alyssa Clevenstine, Office of
Protected Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Purpose and Need for Regulatory Action

This proposed rule, if promulgated, would provide a framework under
the authority of the MMPA (16 U.S.C. 1361 et seq.) to allow for the
authorization of take of marine mammals incidental to the Action
Proponents' training and testing activities (which qualify as military
readiness activities) involving the use of active sonar and other
transducers, air guns, and explosives (also referred to as ``in-water
detonations''); pile driving and vibratory extraction; and vessel
movement in the AFTT Study Area. The AFTT Study Area includes air and
water space of the western Atlantic Ocean along the east coast of North
America, the Gulf of America (formerly Gulf of Mexico), and portions of
the Caribbean Sea, covering approximately 2.6 million square nautical
miles (nmi\2\; 8.9 million square kilometers (km\2\)) of ocean area
(see figure 1.1-1 of the rulemaking and LOA application (hereafter
referred to as the application)). Please see the Legal Authority for
the Proposed Action section for relevant definitions.

Legal Authority for the Proposed Action

The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed authorization is provided to the public for review and the
opportunity to submit comment.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking; other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the monitoring and
reporting of the takings. The MMPA defines ``take'' to mean to harass,
hunt, capture, or kill, or attempt to harass, hunt, capture, or kill
any marine mammal. The Preliminary Analysis and Negligible Impact
Determination section discusses the definition of ``negligible
impact.''
The 2004 NDAA (Pub. L. 108-136) amended section 101(a)(5) of the
MMPA to remove the ``small numbers'' and ``specified geographical
region'' provisions and amended the definition of ``harassment'' as
applied to a ``military readiness activity'' to read as follows
(section 3(18)(B) of the MMPA): (i) Any act that injures or has the
significant potential to injure a marine mammal or marine mammal stock
in the

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wild (Level A Harassment); or (ii) Any act that disturbs or is likely
to disturb a marine mammal or marine mammal stock in the wild by
causing disruption of natural behavioral patterns, including, but not
limited to, migration, surfacing, nursing, breeding, feeding, or
sheltering, to a point where such behavioral patterns are abandoned or
significantly altered (Level B Harassment). The 2004 NDAA also amended
the MMPA establishing that ``[f]or military readiness activity . . . ,
a determination of `least practicable adverse impact' . . . shall
include consideration of personnel safety, practicality of
implementation, and impact on the effectiveness of the military
readiness activity.'' On August 13, 2018, the NDAA for Fiscal Year 2019
(2019 NDAA) (Pub. L. 115-232) amended the MMPA to allow incidental take
regulations for military readiness activities to be issued for up to 7
years.

Summary of Major Provisions Within the Proposed Rule

The major provisions of this proposed rule are:
(i) The proposed take of marine mammals by Level A harassment and/
or Level B harassment;
(ii) The proposed take of marine mammals by mortality or serious
injury (M/SI);
(iii) The proposed use of defined powerdown and shutdown zones
(based on activity);
(iv) Proposed measures to reduce the likelihood of vessel strikes;
(v) Proposed activity limitations in certain areas and times that
are biologically important (i.e., for foraging, migration,
reproduction) for marine mammals;
(vi) The proposed implementation of a Notification and Reporting
Plan (for dead, live stranded, or marine mammals struck by any vessel
engaged in military readiness activities); and
(vii) The proposed implementation of a robust monitoring plan to
improve our understanding of the environmental effects resulting from
the Action Proponents' training and testing activities.
This proposed rule includes an adaptive management component that
allows for timely modification of mitigation, monitoring, and/or
reporting measures based on new information, when appropriate.

Summary of Request

On May 28, 2024, NMFS received an application from the Action
Proponents requesting authorization to take marine mammals, by Level A
and Level B harassment, incidental to training and testing
(characterized as military readiness activities) including the use of
sonar and other transducers, in-water detonations, air guns, and impact
and vibratory pile driving and extraction conducted within the AFTT
Study Area. In addition, the Action Proponents are requesting
authorization to take, by serious injury or mortality, a limited number
of several marine mammal species from explosives during training
exercises, ship shock trials, and vessel movement during military
readiness activities conducted within the AFTT Study Area over the 7-
year period of the LOAs. In response to our comments and following
information exchange, the Action Proponents submitted a final revised
application on August 16, 2024, that we determined was adequate and
complete on August 19, 2024. On October 8, 2024, the Action Proponents
submitted an updated application to revise take estimates on a subset
of Navy activities. On September 20, 2024, we published a notice of
receipt (NOR) of application in the Federal Register (89 FR 77106),
requesting comments and information related to the Action Proponents'
request for 30 days. During the 30-day public comment period on the
NOR, we did not receive any public comments. On January 21, 2025, the
Action Proponents submitted an updated application that removed ship
shock trials and estimated take associated with that activity in Key
West and within the Virginia Capes (VACAPES) Range Complex and, on
February 13, 2025, the Action Proponents submitted an updated
application containing minor revisions.
NMFS has previously promulgated incidental take regulations
pursuant to the MMPA relating to similar military readiness activities
in AFTT. NMFS published the first rule effective from January 22, 2009
through January 22, 2014 (74 FR 4844, January 27, 2009), the second
rule effective from November 14, 2013 through November 13, 2018 (78 FR
73009, December 4, 2013), and the third rule effective from November
14, 2018 through November 13, 2023 (83 FR 57076, November 14, 2018),
which was subsequently amended, extending the effective date until
November 13, 2025 (84 FR 70712, December 23, 2019) pursuant to the 2019
NDAA. For this proposed rulemaking, the Action Proponents propose to
conduct substantially similar training and testing activities within
the AFTT Study Area that were conducted under previous rules.
The Action Proponents' application reflects the most up-to-date
compilation of training and testing activities deemed necessary to
accomplish military readiness requirements. The types and numbers of
activities included in the proposed rule account for fluctuations in
training and testing to meet evolving or emergent military readiness
requirements. These proposed regulations would cover military readiness
activities in the AFTT Study Area that would occur for a 7-year period
following the expiration of the existing MMPA authorization on November
13, 2025.

Description of Proposed Activity

Overview

The Action Proponents request authorization to take marine mammals
incidental to conducting military readiness activities. The Action
Proponents have determined that acoustic and explosives stressors are
most likely to result in take of marine mammals that could rise to the
level of harassment, and take by serious injury or mortality may result
from vessel movement, explosive use, and ship shock trials. Detailed
descriptions of these activities are provided in chapter 2 of the 2024
AFTT Draft Supplemental Environmental Impact Statement (EIS)/Overseas
EIS (OEIS) (2024 AFTT Draft Supplemental EIS/OEIS) (https://www.nepa.navy.mil/aftteis/) and in the Action Proponents' application
(https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities) and are
summarized here.
The Navy's statutory mission is to organize, train, equip, and
maintain combat-ready naval forces for the peacetime promotion of the
national security interests and prosperity of the United States, and
for prompt and sustained combat incident to operations essential to the
prosecution of a naval campaign. These missions are mandated by Federal
law (10 U.S.C. 8062 and 10 U.S.C. 8063), which requires the readiness
of the naval forces of the United States. The Navy executes this
responsibility by establishing and executing at-sea training and
testing, often in designated operating areas (OPAREA) and testing and
training ranges. The Navy must be able to access and utilize these
areas and associated sea and air space to develop and maintain skills
for conducting naval operations. The Navy's testing activities ensure
naval forces are equipped with well-maintained systems that take
advantage of the latest technological advances. The Navy's research and
acquisition community conducts military readiness activities that
involve testing. The Navy tests vessels, aircraft, weapons, combat
systems, sensors, and

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related equipment, and conducts scientific research activities to
achieve and maintain military readiness.
The mission of the Coast Guard is to ensure the maritime safety,
security, and stewardship of the United States. To advance this
mission, the Coast Guard must ensure its personnel can qualify and
train jointly with, and independently of, the Navy and other services
in the effective and safe operational use of Coast Guard vessels,
aircraft, and weapons under realistic conditions. These activities help
ensure the Coast Guard can safely assist in the defense of the United
States by protecting the United States' maritime safety, security, and
natural resources in accordance with its national defense mission (14
U.S.C. 102). Coast Guard training activities are described in more
detail in appendix C of the 2024 AFTT Draft Supplemental EIS/OEIS and
in the Action Proponents' application, and are summarized below.

Dates and Duration

The specified activities would occur at any time during the 7-year
period of validity of the regulations. The proposed number of military
readiness activities are described in the Detailed Description of the
Specified Activity section (table 4 through table 9).

Specified Geographical Region

The AFTT Study Area includes areas of the western Atlantic Ocean
along the east coast of North America, the Gulf of America, and
portions of the Caribbean Sea, covering approximately 2.6 million
nmi\2\ (8.9 million km\2\) of ocean area, oriented from the mean high
tide line along the U.S. coast and extending east to 45-degree west
longitude line, north to 65-degree north latitude line, and south to
approximately the 20-degree north latitude line (figure 1). It also
includes Navy and Coast Guard pierside locations and port transit
channels, bays, harbors, inshore waterways (e.g., channels, rivers),
and civilian ports where military readiness activities occur as well as
vessel and aircraft transit routes between homeports and OPAREAs. New
to the Study Area are inshore waters adjacent to the Gulf of America
and changes to ship shock trial areas. The VACAPES and Key West ship
shock trial areas were removed from the Study Area, the Gulf of America
ship shock trial area was moved south, and the Jacksonville ship shock
trial area expanded. The vast majority of military readiness activities
occur within appropriately designated range complexes and testing
ranges that fall within the confines of the Study Area. Please refer to
figure 1.1-1 of the application for a color map of the AFTT Study Area
and figure 2.1-1 through figure 2.1-5 for additional maps of the range
complexes and testing ranges. A summary of the AFTT Range Complexes and
Testing Ranges are provided in table 1, Inshore Areas are provided in
table 2, and Ports and Piers are provided in table 3.
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Table 1--AFTT Study Area Training and Testing Ranges
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Name Basic location Sea and undersea space Air space
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Northeast Range Complexes............ 750 miles along the 46,000 nmi\2\ of sea 29,000 nmi\2\ of
coast from Maine to and undersea space. special use airspace.
New Jersey. Includes three
OPAREAs: Boston,
Narragansett Bay, and
Atlantic City.
Naval Undersea Warfare Center Includes the waters of 11,000 nmi\2\ of sea Minimal testing occurs
Division, Newport Testing Range. Narragansett Bay, and undersea space. in airspace within the
Rhode Island Sound, Includes three test area.
Block Island Sound, Restricted Areas:
Buzzards Bay, Vineyard Coddington Cove,
Sound, and Long Island Narragansett Bay, and
Sound. Rhode Island Sound.
Virginia Capes Range Complex (VACAPES 250 miles along the 30,000 nmi\2\ of sea 30,000 nmi\2\ of
RC). coast from Delaware to and undersea space. special use airspace.
North Carolina, from Includes one OPAREA:
the shoreline to 150 Virginia Capes.
nmi seaward.
Navy Cherry Point Range Complex...... Off the coast of North 19,000 nmi\2\ of sea 19,000 nmi\2\ of
and South Carolina, and undersea space. special use airspace.
from the shoreline to Includes one OPAREA:
120 nmi seaward. Navy Cherry Point.
Jacksonville Range Complex (JAX RC).. 520 miles along the 50,000 nmi\2\ of sea 64,000 nmi\2\ of
coast from North and undersea space. special use airspace.
Carolina to Florida, Includes three
from the shoreline to OPAREAs: Charleston,
roughly 250 nmi Jacksonville and Cape
seaward. Canaveral. Includes
the Undersea Warfare
Training Range.
Naval Surface Warfare Center, Located adjacent to the 500 nmi\2\ of sea and No associated special
Carderock Division, South Florida Port Everglades undersea space. use airspace.
Ocean Measurement Facility Testing entrance channel in
Range (SFOMF). Fort Lauderdale,
Florida; out to
roughly 25 nmi from
shore.
Key West Range Complex............... Off the southwestern 8,000 nmi\2\ of sea and 23,000 nmi\2\ of
coast of mainland undersea space south special use airspace.
Florida and along the of Key West. Includes
southern Florida Keys, one OPAREA: Key West.
extending into the
Gulf of America and
the Straits of Florida.
Naval Surface Warfare Center, Panama Off the panhandle of 23,000 nmi\2\ of sea 23,000 nmi\2\ of
City Division Testing Area. Florida and Alabama, and undersea space. special use airspace.
extending from the Includes two OPAREAs:
shoreline 120 nmi Panama City and
seaward and includes Pensacola.
St. Andrew Bay.
Gulf Range Complex (Gulf RC)......... Includes geographically 20,000 nmi\2\ of sea 43,000 nmi\2\ of
separated areas and undersea space. special use airspace.
throughout the Gulf of Includes four OPAREAs:
America. Panama City,
Pensacola, New
Orleans, and Corpus
Christi.
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Note: nmi = nautical mile, nmi\2\ = square nautical mile, areas and distances of locations, sea and undersea
space, and airspace are approximations.

Table 2--AFTT Study Area Inshore Locations
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Name Associated inshore waters
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Northeast Range Complexes Thames River, Narragansett Bay, Rhode
Inshore. Island Sound, Block Island Sound.
Virginia Capes Range Complex Lower Chesapeake Bay, James River and
(VACAPES RC) Inshore. tributaries, Broad Bay, York River.
Jacksonville Range Complex Blount Island, Southeast Kings Bay,
(JAX RC) Inshore. Cooper River, St. Johns River, Port
Canaveral.
Key West Range Complex Truman Harbor, Demolition Key.
Inshore.
Gulf Range Complex (Gulf RC) St. Andrew Bay, Atchafalaya Bay,
Inshore. Atchafalaya River, Lake Borgne,
Pascagoula River, Mobile Bay.
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Note: The Gulf Range Complex Inshore includes geographically separated
areas throughout the Gulf of America.

Table 3--AFTT Study Area Ports and Piers
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Coast Guard
Pierside locations Civilian ports locations
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Portsmouth Naval Shipyard Bath, ME Southwest Harbor,
ME
Naval Submarine Base New Boston, MA Boston, MA
London
Naval Station Newport Earle, NJ Cape Cod, MA
Naval Station Norfolk Delaware Bay, DE New London, CT *
Joint Expeditionary Base Hampton Roads, VA New Haven CT *
Little Creek Fort Story
Norfolk Naval Shipyard Morehead City, NC Newport, RI *
Naval Submarine Base Kings Wilmington, NC Montauk, NY
Bay
Naval Station Mayport Kings Bay, GA Staten Island, NY *
Port Canaveral Savannah, GA Atlantic City, NJ
Mayport, FL Chesapeake, VA
Port Canaveral, FL Virginia Beach, VA
*
Tampa, FL Portsmouth, VA*
Pascagoula, MS Elizabeth City, NC
Gulfport, MS Charleston, SC *
Beaumont, TX Mayport, FL *
Corpus Christi, TX Cape Canaveral, FL
*
Fort Pierce, FL *
Dania, FL *
Miami, FL *
Key West, FL *
St. Petersburg, FL
*
Pensacola, FL *
Opa Locka, FL
New Orleans, LA
Houston, TX
Corpus Christi, TX
------------------------------------------------------------------------
Note: CT: Connecticut; FL: Florida; GA: Georgia; LA: Louisiana; MA:
Massachusetts; ME: Maine; MS: Mississippi; NC: North Carolina; NJ: New
Jersey; NY: New York; RI: Rhode Island; SC: South Carolina; TX: Texas;
VA: Virginia.

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* Indicates Coast Guard cutter stations.

Detailed Description of the Specified Activity

The Action Proponents propose to conduct military readiness
activities within the AFTT Study Area and have been conducting military
readiness activities in the Study Area for well over a century and with
active sonar for over 70 years. The tempo and types of military
readiness activities have fluctuated due to the introduction of new
technologies, the evolving nature of international events, advances in
warfighting doctrine and procedures, and changes in force structure
(organization of vessels, weapons, and personnel). Such developments
influenced the frequency, duration, intensity, and location of required
military readiness activities.
Primary Mission Areas
The Navy categorizes their activities into functional warfare areas
called primary mission areas, while the Coast Guard categorizes their
activities as operational mission programs. For the Navy, these
activities generally fall into the following five primary mission areas
(Coast Guard mission areas are discussed below). The Navy mission areas
with activities that may result in incidental take of marine mammals
(and stressors associated with training and testing activities within
those mission areas) include the following:
(i) Amphibious warfare (in-water detonations);
(ii) Anti-submarine warfare (sonar and other transducers, in-water
detonations);
(iii) Expeditionary warfare (in-water detonations, pile driving and
extraction);
(iv) Mine warfare (sonar and other transducers, in-water
detonations);
(v) Surface warfare (in-water detonations); and
(vi) Other (sonar and other transducers, air guns, vessel
movement).
Most Navy activities conducted in AFTT are categorized under one of
these primary mission areas; activities that do not fall within one of
these areas are listed as ``other activities.'' In addition, ship shock
(in-water detonations) trials, a specific Navy testing activity related
to vessel evaluation, would be conducted. The testing community also
categorizes most, but not all, of its testing activities under these
primary mission areas. The testing community has three additional
categories of activities: vessel evaluation (inclusive of ship shock
trials), unmanned systems (i.e., unmanned surface vehicles (USVs),
unmanned underwater vehicles (UUVs)), and acoustic and oceanographic
science and technology.
The Action Proponents describe and analyze the effects of their
activities within the application (see the 2024 AFTT Draft Supplemental
EIS/OEIS for additional details). In their assessment, the Action
Proponents concluded that sonar and other transducers, underwater
detonations, air guns, and pile driving/extraction were the stressors
most likely to result in impacts on marine mammals that could rise to
the level of harassment (and serious injury or mortality by explosives
or by vessel movement) as defined under the MMPA. Therefore, the Action
Proponents' application provides their assessment of potential effects
from these stressors in terms of the primary warfare mission areas in
which they would be conducted.
The Coast Guard has four major national defense missions:
(i) Maritime intercept operations;
(ii) Deployed port operations/security and defense;
(iii) Peacetime engagement; and
(iv) Environmental defense operations (which includes oil and
hazardous substance response).
The Coast Guard manages 6 major operational mission programs with
11 statutory missions, which includes defense readiness. As part of the
Coast Guard's defense mission, Title 14 U.S.C. 1 states the Coast Guard
is ``at all times an armed force of the United States.'' As part of the
Joint Forces, the Coast Guard maintains its readiness to carry out
military operations in support of the policies and objectives of the
U.S. government. As an armed force, the Coast Guard trains and operates
in the joint military arena at any time and functions as a specialized
service under the Navy in time of war or when directed by the
President. Coast Guard service members are trained to respond
immediately to support military operations and national security.
Federal law created the framework for the relationship between the Navy
and the Coast Guard (10 U.S.C. 101; 14 U.S.C. 2(7); 22 U.S.C.; 50
U.S.C.). To meet these statutory requirements and effectively carry out
these missions, the Coast Guard's air and surface units train using
realistic scenarios, including training with the Navy in their primary
mission areas. Every Coast Guard unit is trained to support all
statutory missions and, thus, trained to meet all mission requirements,
which includes their defense mission requirements. Since all Coast
Guard's missions entail the deployment of cutters or boats and either
fixed-wing or rotary aircraft, the Coast Guard training requirements
for one mission generally overlaps with the training requirements of
other missions. Thus, when the Coast Guard is training for its defense
mission, the same skill sets are utilized for its other statutory
missions.
The Coast Guard's defense mission does not involve low- or mid-
frequency active sonar (LFAS or MFAS), missiles, in-water detonations,
pile driving and extraction, or air guns that would result in
harassment of marine mammals. For additional information on all
activities in the Coast Guard's mission programs see appendix C of the
2024 AFTT Draft Supplemental EIS/OEIS.
Below, we provide additional detail for each of the applicable
primary mission areas.
Amphibious Warfare--
The mission of amphibious warfare is to project military power from
the sea to the shore (i.e., attack a threat on land by a military force
embarked on ships) through the use of naval firepower and expeditionary
landing forces. Amphibious warfare operations include Navy and Marine
Corps small unit reconnaissance or raid missions to large-scale
amphibious exercises involving multiple ships and aircraft combined
into a strike group.
Amphibious warfare training ranges from individual, crew, and small
unit events to large task force exercises. Individual and crew training
include amphibious vehicles and naval gunfire support training. Such
training includes shore assaults, boat raids, airfield or port
seizures, reconnaissance, and disaster relief. Large-scale amphibious
exercises involve ship-to-shore maneuvers, naval fire support such as
shore bombardment, air strikes, and attacks on targets that are near
friendly forces.
Testing of guns, munitions, aircraft, ships, and amphibious vessels
and vehicles used in amphibious warfare are often integrated into
training activities and, in most cases, the systems are used in the
same manner in which they are used for training activities. Amphibious
warfare tests, when integrated with training activities or conducted
separately as full operational evaluations on existing amphibious
vessels and vehicles following maintenance, repair, or modernization,
may be conducted independently or in conjunction with other amphibious
ship and aircraft activities. Testing is performed to ensure effective
ship-to-

[[Page 19864]]

shore coordination and transport of personnel, equipment, and supplies.
Tests may also be conducted periodically on other systems, vessels, and
aircraft intended for amphibious operations to assess operability and
to investigate efficacy of new technologies.
Anti-Submarine Warfare--
The mission of anti-submarine warfare is to locate, neutralize, and
defeat hostile submarine forces that threaten Navy forces. Anti-
submarine warfare is based on the principle that surveillance and
attack aircraft, ships, and submarines all search for hostile
submarines. These forces operate together or independently to gain
early warning and detection and to localize, track, target, and attack
submarine threats.
Anti-submarine warfare training addresses basic skills such as
detecting and classifying submarines, as well as evaluating sounds to
distinguish between enemy submarines and friendly submarines, ships,
and marine life. More advanced training integrates the full spectrum of
anti-submarine warfare from detecting and tracking a submarine to
attacking a target using either exercise torpedoes (i.e., torpedoes
that do not contain a warhead) or simulated weapons. These integrated
anti-submarine warfare training exercises are conducted in coordinated,
at-sea training events involving submarines, ships, and aircraft.
Testing of anti-submarine warfare systems is conducted to develop
new technologies and assess weapon performance and operability with new
systems and platforms, such as unmanned systems. Testing uses ships,
submarines, and aircraft to demonstrate capabilities of torpedoes,
missiles, countermeasure systems, and underwater surveillance and
communications systems. Tests may be conducted as part of a large-scale
fleet training event involving submarines, ships, fixed-wing aircraft,
and helicopters. These integrated training events offer opportunities
to conduct research and acquisition activities and to train aircrew in
the use of new or newly enhanced systems during a large-scale, complex
exercise.
Expeditionary Warfare--
The mission of expeditionary warfare is to provide security and
surveillance in the littoral (at the shoreline), riparian (along a
river), or coastal environments. Expeditionary warfare is wide ranging
and includes defense of harbors, operation of remotely operated
vehicles, defense against swimmers, and boarding/seizure operations.
Expeditionary warfare training activities include Navy, Marine
Corps, and Coast Guard underwater construction team training, dive and
salvage operations, and insertion/extraction via air, surface, and
subsurface platforms.
Mine Warfare--
The mission of mine warfare is to detect, classify, and avoid or
neutralize (disable) mines to protect U.S. ships and submarines, and to
maintain free access to ports and shipping lanes. Mine warfare training
for the Navy and Coast Guard falls into two primary categories: mine
detection and classification, and mine countermeasure and
neutralization. Mine warfare also includes offensive mine laying to
gain control of or deny the enemy access to sea space. Naval mines can
be laid by ships, submarines, UUVs, or aircraft.
Mine warfare neutralization training includes exercises in which
aircraft, ships, submarines, underwater vehicles, unmanned vehicles, or
marine mammal detection systems search for mine shapes. Personnel train
to destroy or disable mines by attaching underwater explosives to or
near the mine or using remotely operated vehicles to destroy the mine.
Mine warfare testing is similar to training but focuses on the
development of mine warfare systems to improve sonar, laser, and
magnetic detectors intended to hunt, locate, and record the positions
of mines for avoidance or subsequent neutralization. Mine detection and
classification testing involves the use of air, surface, and subsurface
platforms using a variety of systems to locate and identify objects
underwater. Mine countermeasure and neutralization testing includes the
use of air, surface, and subsurface platforms to evaluate the
effectiveness of tracking devices, countermeasure and neutralization
systems, and explosive munitions to neutralize mine threats. Most
neutralization tests use mine shapes, or non-explosive practice mines,
to evaluate a new or enhanced capability; however, a small percentage
require the use of high-explosive mines to evaluate and confirm
effectiveness of various systems.
Surface Warfare--
The mission of surface warfare is to obtain control of sea space
from which naval forces may operate and entails offensive action
against other surface and subsurface targets while also defending
against enemy forces. In surface warfare, aircraft use cannons, air-to-
surface missiles, and other precision-guided munitions; ships employ
torpedoes, naval guns, and surface-to-surface missiles; and submarines
attack surface ships using torpedoes.
Surface warfare training includes Navy and Coast Guard surface-to-
surface gunnery and missile exercises, air-to-surface gunnery, bombing,
and missile exercises, submarine torpedo launch events, other munitions
against surface targets, and amphibious operations in a contested
environment.
Testing of weapons used in surface warfare is conducted to develop
new technologies and to assess weapon performance and operability with
new systems and platforms, such as unmanned systems. Tests include
various air-to-surface guns and missiles, surface-to-surface guns and
missiles, and bombing tests. Testing events may be integrated into
training activities to test aircraft or aircraft systems in the
delivery of ordnance on a surface target. In most cases the tested
systems are used in the same manner in which they are used for training
activities.
Overview of Training Activities Within the Study Area
The Action Proponents routinely train in the AFTT Study Area in
preparation for national defense missions. Training activities and
exercises covered in this proposed rule are briefly described below and
in more detail within appendix A (Activity Descriptions) of the 2024
AFTT Draft Supplemental EIS/OEIS. The description, annual number of
activities, and location of each training activity are provided by
stressor category in table 4, table 5, and table 6. Each training
activity described meets a requirement that can be traced ultimately to
requirements set forth by the National Command Authority.
Within the Navy, a major training exercise (MTE) is comprised of
multiple ``unit-level'' exercises conducted by several units operating
together while commanded and controlled by a single commander (these
units are collectively referred to as carrier and expeditionary strike
groups). These exercises typically employ an exercise scenario
developed to train and evaluate the strike group in tactical naval
tasks. In a MTE, most of the operations and activities being directed
and coordinated by the strike group commander are identical in nature
to the operations conducted during individual, crew, and smaller unit-
level training events. However, in MTEs, these disparate training tasks
are conducted in concert rather than in isolation. Some integrated or
coordinated anti-submarine warfare exercises are similar in that they
are composed of several unit-level exercises

[[Page 19865]]

but are generally on a smaller scale than a MTE, are shorter in
duration, use fewer assets, and use fewer hours of hull-mounted sonar
per exercise. Coordinated training exercises involve multiple units
working together to meet unit-level training requirements, whereas
integrated training exercises involve multiple units working together
for deployment. Coordinated exercises involving the use of sonar are
presented under the category of anti-submarine warfare. The anti-
submarine warfare portions of these exercises are considered together
in coordinated activities for the sake of acoustic modeling. When other
training objectives are being met, those activities are described via
unit-level training in each of the relevant primary mission areas.
With a smaller fleet of approximately 250 cutters, Coast Guard
activities are not as extensive as Navy activities due to differing
mission requirements. However, the Coast Guard does train with the Navy
and conducts some of the same training as the Navy. The Coast Guard
does not conduct any exercises similar in scale to Navy MTEs/integrated
exercises, and the use of mid- or low-frequency sonar, missiles, and
underwater detonations are examples of actions that are not a part of
the Coast Guard's mission requirements. Coast Guard training generally
occurs close to the vessel homeport or close to shore, on established
Navy testing and training ranges, or in transit to a scheduled patrol/
mission. There are approximately 1,600 Coast Guard vessels (cutters up
to 418 feet (ft; 127.4 meters (m)) and boats less than 65 ft (19.8 m)),
and the largest cutters would be underway for 3 to 4 months, whereas
the smaller cutters would be underway from a few days to 4 weeks. The
busiest regions for the Coast Guard are the Gulf of America due to the
number of busy commercial ports, and Hampton Roads due to many of the
cutters being based at facilities in that area.
The MTEs and integrated/coordinated training activities analyzed
for this request are Navy-led exercises in which the Coast Guard may
participate and described in table 4. For additional information on
these activities, see table 1.3-1 of the application and appendix A
(Activity Descriptions) of the 2024 AFTT Draft Supplemental EIS/OEIS.
Table 5 describes the proposed Navy training activities analyzed within
the AFTT Study Area while table 6 describes the proposed Coast Guard
training activities analyzed within the AFTT Study Area. In addition to
participating in Navy-led exercises, Coast Guard training activities
include unit-level activities conducted independently of, and not in
coordination with, the Navy.

Table 4--Major Training Exercises and Integrated/Coordinated Training Activities Analyzed Within the AFTT Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
Typical hull-
Training type Exercise group Description Scale Duration Location (range Exercise mounted sonar
complex) examples per event
--------------------------------------------------------------------------------------------------------------------------------------------------------
Major Training Exercise...... Large Integrated Larger-scale, Greater than 6 Generally Jacksonville COMPTUEX....... <500 hours.
ASW. longer duration surface ASW greater than Range Complex,
integrated ASW units (up to 10 days. Navy Cherry
exercises. 30 with the Point Range
largest Complex,
exercises), 2 Virginia Capes
or more Range Complex.
submarines,
multiple ASW
aircraft.
Major Training Exercise...... Medium Medium-scale, Approximately 3- Generally 4-10 Jacksonville Sustainment/ 100-300 hours.
Integrated ASW. medium duration 8 surface ASW days. Range Complex, Task Force
integrated ASW units, at Navy Cherry Exercise.
exercises. least 1 Point Range
submarine, Complex,
multiple ASW Virginia Capes
aircraft. Range Complex.
Integrated/Coordinated Small Integrated Small-scale, Approximately 3- Generally less Jacksonville SWATT, NUWTAC.. 50-100 hours.
Training. ASW. short duration 6 surface ASW than 5 days. Range Complex,
integrated ASW units, 2 Navy Cherry
exercises. dedicated Point Range
submarines, 2- Complex,
6 ASW aircraft. Virginia Capes
Range Complex.
Integrated/Coordinated Medium Medium-scale, Approximately 2- Generally 3-10 Jacksonville ASW Tactical <100 hours.
Training. Coordinated ASW. medium 4 surface ASW days. Range Complex, Development
duration, units, Navy Cherry Exercise.
coordinated ASW possibly a Point Range
exercises. submarine, 2-5 Complex,
ASW aircraft. Virginia Capes
Range Complex.
Integrated/Coordinated Small Small-scale, Approximately 2- Generally 2-4 Jacksonville ARG/MEU <50 hours.
Training. Coordinated ASW. short duration, 4 surface ASW days. Range Complex, COMPTUEX.
coordinated ASW units, Navy Cherry
exercises. possibly a Point Range
submarine, 1-2 Complex,
ASW aircraft. Virginia Capes
Range Complex.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: ASW: anti-submarine warfare; COMPTUEX: Composite Training Unit Exercise; SWATT: Surface Warfare Advanced Tactical Training Exercise; NUWTAC: Navy
Undersea Warfare Training Assessment Course; ARG/MEU: Amphibious Ready Group/Marine Expeditionary Unit.

[[Page 19866]]

Table 5--Proposed Navy Training Activities Analyzed Within the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Number of Number of
Stressor category Activity type Activity name Description Source bin activities activities Location
1-year 7-year
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Acoustic.................. Major Training Composite Training Aircraft carrier and carrier air wing integrate LFH, MFM, MFH, MF1, 2-3 17 Jacksonville Range
Exercise--Large Unit Exercise. with surface and submarine and Coast Guard MF1C, Broadband (MF Complex, Navy
Integrated ASW. units in a challenging multi-threat to HF). Cherry Point Range
operational environment that certifies them Complex, Virginia
ready to deploy. Capes Range
Complex.
Acoustic.................. Major Training Sustainment/Task Aircraft carrier and carrier air wing LFH, MFM, MFH, MF1, 2 14 Jacksonville Range
Exercise--Medium Force Exercise. integrates with surface and submarine units in MF1C, Broadband (MF Complex, Navy
Integrated ASW. a challenging multi-threat operational to HF). Cherry Point Range
environment to maintain ability to deploy. Complex, Virginia
Capes Range
Complex.
Acoustic.................. Small Integrated ASW Navy Undersea Warfare Multiple ships, aircraft, and submarines LFH, MFM, MFH, MF1, 2 14 Jacksonville Range
Training. Training Assessment integrate the use of their sensors, including MF1C, Broadband (MF Complex, Navy
Course. sonobuoys, to search for, detect, classify, to HF). Cherry Point Range
localize, and track a threat submarine. Complex, Virginia
Capes Range
Complex.
Acoustic.................. Small Integrated ASW Surface Warfare Multiple ships and aircraft coordinate the use LFH, MFM, MFH, MF1, 2 14 Jacksonville Range
Training. Advanced Tactical of sensors, including sonobuoys, to search, MF1C, Broadband (MF Complex, Navy
Training. detect, and track a threat submarine. Surface to HF). Cherry Point Range
Warfare Advanced Tactical Training (SWATT) Complex, Virginia
exercises are not dedicated anti-submarine Capes Range
warfare exercises and involve multiple warfare Complex.
areas.
Acoustic.................. Medium Coordinated Tactical Development Multiple ships, aircraft, and submarines MFM, MFH, MF1, MF1C, 1 7 Jacksonville Range
ASW Training. Exercise. coordinate their efforts to search for, Broadband (MF to HF). Complex.
detect, and track submarines with the use of
all sensors. Anti-Submarine Warfare Tactical
Development Exercise is a dedicated anti-
submarine warfare exercise.
Acoustic.................. Medium Coordinated Tactical Development Multiple ships, aircraft, and submarines MFM, MFH, MF1, MF1C, 1 7 Virginia Capes Range
ASW Training. Exercise. coordinate their efforts to search for, Broadband (MF to HF). Complex.
detect, and track submarines with the use of
all sensors. Anti-Submarine Warfare Tactical
Development Exercise is a dedicated anti-
submarine warfare exercise.
Acoustic.................. Small Coordinated ASW Group Sail........... Surface ships, Coast Guard Cutters, and MFM, MFH, MF1, MF1C, 5 35 Jacksonville Range
Training. helicopters integrate to search for, detect, Broadband (MF to HF). Complex.
and track threat submarines. Group Sails are
not dedicated anti-submarine warfare exercises
and involve multiple warfare areas.
Acoustic.................. Small Coordinated ASW Group Sail........... Surface ships, Coast Guard Cutters, and MFM, MFH, MF1, MF1C, 4 28 Navy Cherry Point
Training. helicopters integrate to search for, detect, Broadband (MF to HF). Range Complex.
and track threat submarines. Group Sails are
not dedicated anti-submarine warfare exercises
and involve multiple warfare areas.
Acoustic.................. Small Coordinated ASW Group Sail........... Surface ships, Coast Guard Cutters, and MFM, MFH, MF1, MF1C, 5 35 Virginia Capes Range
Training. helicopters integrate to search for, detect, Broadband (MF to HF). Complex.
and track threat submarines. Group Sails are
not dedicated anti-submarine warfare exercises
and involve multiple warfare areas.
Acoustic.................. Small Coordinated ASW Amphibious Ready Amphibious Ready Group exercises are conducted LFH, MFM, MFH, MF1, 1 7 Navy Cherry Point
Training. Group Marine to validate the Marine Expeditionary Unit's Broadband (MF to HF). Range Complex.
Expeditionary Unit readiness for deployment and include small
Composite Training boat raids; visit, board, search, and seizure
Unit Exercise. training; helicopter and mechanized amphibious
raids; and non-combatant evacuation
operations.
Explosive................. Amphibious Warfare... Amphibious Operations Navy and Marine Corps forces conduct operations E1, E2, E3, E6, E9, 45 315 Navy Cherry Point
in a Contested in coastal and offshore waterways against air, E10. Range Complex.
Environment. surface, and subsurface threats.

[[Page 19867]]

Explosive................. Amphibious Warfare... Amphibious Operations Navy and Marine Corps forces conduct operations E1, E2, E3, E6, E9, 12 84 Virginia Capes Range
in a Contested in coastal and offshore waterways against air, E10. Complex.
Environment. surface, and subsurface threats.
Acoustic.................. Anti-Submarine Anti-Submarine Helicopter crews search for, track, and detect MFM, MFH, HFH, 14 98 Jacksonville Range
Warfare. Warfare Torpedo submarines. Recoverable air launched torpedoes Broadband (MF to HF). Complex.
Exercise--Helicopter. are employed against submarine targets.
Acoustic.................. Anti-Submarine Anti-Submarine Helicopter crews search for, track, and detect MFM, MFH, HFH, 4 28 Virginia Capes Range
Warfare. Warfare Torpedo submarines. Recoverable air launched torpedoes Broadband (MF to HF). Complex.
Exercise--Helicopter. are employed against submarine targets.
Acoustic.................. Anti-Submarine Anti-Submarine Maritime patrol aircraft crews search for, MFM, HFH, Broadband 14 98 Jacksonville Range
Warfare. Warfare Torpedo track, and detect submarines. Recoverable air (MF to HF). Complex.
Exercise--Maritime launched torpedoes are employed against
Patrol Aircraft. submarine targets.
Acoustic.................. Anti-Submarine Anti-Submarine Maritime patrol aircraft crews search for, MFM, HFH, Broadband 4 28 Virginia Capes Range
Warfare. Warfare Torpedo track, and detect submarines. Recoverable air (MF to HF). Complex.
Exercise--Maritime launched torpedoes are employed against
Patrol Aircraft. submarine targets.
Acoustic.................. Anti-Submarine Anti-Submarine Surface ship crews search for, track, and MF1, HFH, Broadband 16 112 Jacksonville Range
Warfare. Warfare Torpedo detect submarines. Exercise torpedoes are used (MF to HF). Complex.
Exercise--Ship. during this exercise.
Acoustic.................. Anti-Submarine Anti-Submarine Surface ship crews search for, track, and MF1, HFH, Broadband 5 35 Virginia Capes Range
Warfare. Warfare Torpedo detect submarines. Exercise torpedoes are used (MF to HF). Complex.
Exercise--Ship. during this exercise.
Acoustic.................. Anti-Submarine Anti-Submarine Submarine crews search for, track, and detect HFH, Broadband (MF to 12 84 Jacksonville Range
Warfare. Warfare Torpedo submarines. Exercise torpedoes are used during HF). Complex.
Exercise--Submarine. this exercise.
Acoustic.................. Anti-Submarine Anti-Submarine Submarine crews search for, track, and detect HFH, Broadband (MF to 6 42 Northeast Range
Warfare. Warfare Torpedo submarines. Exercise torpedoes are used during HF). Complexes.
Exercise--Submarine. this exercise.
Acoustic.................. Anti-Submarine Anti-Submarine Submarine crews search for, track, and detect HFH, Broadband (MF to 2 14 Virginia Capes Range
Warfare. Warfare Torpedo submarines. Exercise torpedoes are used during HF). Complex.
Exercise--Submarine. this exercise.
Acoustic.................. Anti-Submarine Anti-Submarine Helicopter crews search for, track, and detect MFM, MFH............. 3 21 Gulf Range Complex.
Warfare. Warfare Tracking submarines.
Exercise--Helicopter.
Acoustic.................. Anti-Submarine Anti-Submarine Helicopter crews search for, track, and detect MFM, MFH............. 370 2,590 Jacksonville Range
Warfare. Warfare Tracking submarines. Complex.
Exercise--Helicopter.
Acoustic.................. Anti-Submarine Anti-Submarine Helicopter crews search for, track, and detect MFM, MFH............. 12 84 Navy Cherry Point
Warfare. Warfare Tracking submarines. Range Complex.
Exercise--Helicopter.
Acoustic.................. Anti-Submarine Anti-Submarine Helicopter crews search for, track, and detect MFM, MFH............. 24 168 Other AFTT Areas.
Warfare. Warfare Tracking submarines.
Exercise--Helicopter.
Acoustic.................. Anti-Submarine Anti-Submarine Helicopter crews search for, track, and detect MFM, MFH............. 8 56 Virginia Capes Range
Warfare. Warfare Tracking submarines. Complex.
Exercise--Helicopter.
Acoustic.................. Anti-Submarine Anti-Submarine Maritime patrol aircraft crews search for, LFM, LFH, MFM........ 475 3,325 Jacksonville Range
Warfare. Warfare Tracking track, and detect submarines. Complex.
Exercise--Maritime
Patrol Aircraft.
Acoustic.................. Anti-Submarine Anti-Submarine Maritime patrol aircraft crews search for, LFM, LFH, MFM........ 35 245 Navy Cherry Point
Warfare. Warfare Tracking track, and detect submarines. Range Complex.
Exercise--Maritime
Patrol Aircraft.
Acoustic.................. Anti-Submarine Anti-Submarine Maritime patrol aircraft crews search for, LFM, LFH, MFM........ 80 560 Northeast Range
Warfare. Warfare Tracking track, and detect submarines. Complexes.
Exercise--Maritime
Patrol Aircraft.
Acoustic.................. Anti-Submarine Anti-Submarine Maritime patrol aircraft crews search for, LFM, LFH, MFM........ 155 1,085 Virginia Capes Range
Warfare. Warfare Tracking track, and detect submarines. Complex.
Exercise--Maritime
Patrol Aircraft.
Acoustic.................. Anti-Submarine Anti-Submarine Surface ship crews search for, track, and MFH, MF1, MF1C, 5 35 Gulf Range Complex.
Warfare. Warfare Tracking detect submarines. Exercise torpedoes may be Broadband (MF to HF).
Exercise--Ship. used during this event.

[[Page 19868]]

Acoustic.................. Anti-Submarine Anti-Submarine Surface ship crews search for, track, and MFH, MF1, MF1C, 290 2,030 Jacksonville Range
Warfare. Warfare Tracking detect submarines. Exercise torpedoes may be Broadband (MF to HF). Complex.
Exercise--Ship. used during this event.
Acoustic.................. Anti-Submarine Anti-Submarine Surface ship crews search for, track, and MFH, MF1, MF1C, 33 231 Navy Cherry Point
Warfare. Warfare Tracking detect submarines. Exercise torpedoes may be Broadband (MF to HF). Range Complex.
Exercise--Ship. used during this event.
Acoustic.................. Anti-Submarine Anti-Submarine Surface ship crews search for, track, and MFH, MF1, MF1C, 5 35 Northeast Range
Warfare. Warfare Tracking detect submarines. Exercise torpedoes may be Broadband (MF to HF). Complexes.
Exercise--Ship. used during this event.
Acoustic.................. Anti-Submarine Anti-Submarine Surface ship crews search for, track, and MFH, MF1, MF1C, 55 385 Other AFTT Areas.
Warfare. Warfare Tracking detect submarines. Exercise torpedoes may be Broadband (MF to HF).
Exercise--Ship. used during this event.
Acoustic.................. Anti-Submarine Anti-Submarine Surface ship crews search for, track, and MFH, MF1, MF1C, 120 840 Virginia Capes Range
Warfare. Warfare Tracking detect submarines. Exercise torpedoes may be Broadband (MF to HF). Complex.
Exercise--Ship. used during this event.
Acoustic.................. Anti-Submarine Anti-Submarine Submarine crews search for, track, and detect LFH, MFH, HFH........ 13 91 Jacksonville Range
Warfare. Warfare Tracking submarines. Complex.
Exercise--Submarine.
Acoustic.................. Anti-Submarine Anti-Submarine Submarine crews search for, track, and detect LFH, MFH, HFH........ 1 7 Navy Cherry Point
Warfare. Warfare Tracking submarines. Range Complex.
Exercise--Submarine.
Acoustic.................. Anti-Submarine Anti-Submarine Submarine crews search for, track, and detect LFH, MFH, HFH........ 18 126 Northeast Range
Warfare. Warfare Tracking submarines. Complexes.
Exercise--Submarine.
Acoustic.................. Anti-Submarine Anti-Submarine Submarine crews search for, track, and detect LFH, MFH, HFH........ 46 308 Other AFTT Areas.
Warfare. Warfare Tracking submarines.
Exercise--Submarine.
Acoustic.................. Anti-Submarine Anti-Submarine Submarine crews search for, track, and detect LFH, MFH, HFH........ 6 42 Virginia Capes Range
Warfare. Warfare Tracking submarines. Complex.
Exercise--Submarine.
Acoustic.................. Expeditionary Warfare Port Damage Repair... Navy and Coast Guard Expeditionary forces train Pile driving......... 4 28 Gulfport, MS.
to repair critical port facilities.
Acoustic.................. Mine Warfare......... Airborne Mine Helicopter aircrew detect mines using towed or HFH.................. 290 2,030 Gulf Range Complex.
Countermeasures--Min laser mine detection systems.
e Detection.
Acoustic.................. Mine Warfare......... Airborne Mine Helicopter aircrew detect mines using towed or HFH.................. 275 1,925 Jacksonville Range
Countermeasures--Min laser mine detection systems. Complex.
e Detection.
Acoustic.................. Mine Warfare......... Airborne Mine Helicopter aircrew detect mines using towed or HFH.................. 187 1,309 Key West Range
Countermeasures--Min laser mine detection systems. Complex.
e Detection.
Acoustic.................. Mine Warfare......... Airborne Mine Helicopter aircrew detect mines using towed or HFH.................. 321 2,247 Navy Cherry Point
Countermeasures--Min laser mine detection systems. Range Complex.
e Detection.
Acoustic.................. Mine Warfare......... Airborne Mine Helicopter aircrew detect mines using towed or HFH.................. 1,420 9,940 Virginia Capes Range
Countermeasures--Min laser mine detection systems. Complex.
e Detection.
Acoustic.................. Mine Warfare......... Civilian Port Coast Guard and Navy Maritime security MFH, HFM, HFH........ 0-1 4 Boston, MA;
Defense--Homeland personnel train to protect civilian ports and Beaumont, TX;
Security Anti- harbors against enemy efforts to interfere Corpus Christi, TX;
Terrorism/Force with access to those ports. Delaware Bay, DE;
Protection Exercises. Earle, NJ; Hampton
Roads, VA; Kings
Bay, GA; Mayport,
FL; Morehead City,
NC; Port Canaveral,
FL; Savannah, GA;
Tampa, FL;
Wilmington, NC.

[[Page 19869]]

Acoustic and Explosive.... Mine Warfare......... Mine Countermeasures-- Ship, small boat, and helicopter crews locate HFM, E4.............. * 66 * 462 Gulf Range Complex.
Mine Neutralization-- and disable mines using remotely operated
Remotely Operated underwater vehicles. All events include
Vehicles. acoustic sources, only a fraction involve
explosives.
Acoustic and Explosive.... Mine Warfare......... Mine Countermeasures-- Ship, small boat, and helicopter crews locate HFM, E4.............. 36 252 Jacksonville Range
Mine Neutralization-- and disable mines using remotely operated Complex.
Remotely Operated underwater vehicles. All events include
Vehicles. acoustic sources, only a fraction involve
explosives.
Acoustic and Explosive.... Mine Warfare......... Mine Countermeasures-- Ship, small boat, and helicopter crews locate HFM, E4.............. 10 70 Key West Range
Mine Neutralization-- and disable mines using remotely operated Complex.
Remotely Operated underwater vehicles. All events include
Vehicles. acoustic sources, only a fraction involve
explosives.
Acoustic and Explosive.... Mine Warfare......... Mine Countermeasures-- Ship, small boat, and helicopter crews locate HFM, E4.............. * 36 * 252 Navy Cherry Point
Mine Neutralization-- and disable mines using remotely operated Range Complex.
Remotely Operated underwater vehicles. All events include
Vehicles. acoustic sources, only a fraction involve
explosives.
Acoustic and Explosive.... Mine Warfare......... Mine Countermeasures-- Ship, small boat, and helicopter crews locate HFM, E4.............. * 315 * 2,205 Virginia Capes Range
Mine Neutralization-- and disable mines using remotely operated Complex.
Remotely Operated underwater vehicles. All events include
Vehicles. acoustic sources, only a fraction involve
explosives.
Acoustic.................. Mine Warfare......... Mine Countermeasures-- Ship crews detect and avoid mines while HFH.................. 22 * 462 Gulf Range Complex.
Ship Sonar. navigating restricted areas or channels using
active sonar.
Acoustic.................. Mine Warfare......... Mine Countermeasures-- Ship crews detect and avoid mines while HFH.................. 53 252 Jacksonville Range
Ship Sonar. navigating restricted areas or channels using Complex.
active sonar.
Acoustic.................. Mine Warfare......... Mine Countermeasures-- Ship crews detect and avoid mines while HFH.................. 53 70 Virginia Capes Range
Ship Sonar. navigating restricted areas or channels using Complex.
active sonar.
Explosive................. Mine Warfare......... Mine Neutralization Personnel disable threat mines using explosive E6................... * 96 * 672 Gulf Range Complex.
Explosive Ordnance charges.
Disposal.
Explosive................. Mine Warfare......... Mine Neutralization Personnel disable threat mines using explosive E5, E6............... * 100 * 700 Jacksonville Range
Explosive Ordnance charges. Complex.
Disposal.
Explosive................. Mine Warfare......... Mine Neutralization Personnel disable threat mines using explosive E5, E6, E7........... * 30 * 210 Key West Range
Explosive Ordnance charges. Complex.
Disposal.
Explosive................. Mine Warfare......... Mine Neutralization Personnel disable threat mines using explosive E5................... * 176 * 1,232 Key West Range
Explosive Ordnance charges. Complex Inshore.
Disposal.
Explosive................. Mine Warfare......... Mine Neutralization Personnel disable threat mines using explosive E6................... * 86 * 602 Navy Cherry Point
Explosive Ordnance charges. Range Complex.
Disposal.
Explosive................. Mine Warfare......... Mine Neutralization Personnel disable threat mines using explosive E5, E6, E7........... * 325 * 2,275 Virginia Capes Range
Explosive Ordnance charges. Complex.
Disposal.
Acoustic.................. Mine Warfare......... Submarine Mine Laying Submarine crews or UUVs deploy exercise mobile MFM, HFL, HFM, VHFL.. 2 14 Jacksonville Range
mines or mines. Complex.
Acoustic.................. Mine Warfare......... Surface Ship Object Ship crews detect and avoid mines while MF1K................. 76 532 Jacksonville Range
Detection. navigating restricted areas or channels using Complex.
active sonar.
Acoustic.................. Mine Warfare......... Surface Ship Object Ship crews detect and avoid mines while MF1K................. 162 1,134 Virginia Capes Range
Detection. navigating restricted areas or channels using Complex.
active sonar.
Explosive................. Surface Warfare...... Bombing Exercise Air- Fixed-wing aircrew deliver bombs against E9, E10.............. * 47 * 329 Gulf Range Complex.
to-Surface. surface targets.
Explosive................. Surface Warfare...... Bombing Exercise Air- Fixed-wing aircrew deliver bombs against E9, E10.............. * 260 1,820* Jacksonville Range
to-Surface. surface targets. Complex.
Explosive................. Surface Warfare...... Bombing Exercise Air- Fixed-wing aircrew deliver bombs against E9, E10, E12......... * 272 * 1,904 Virginia Capes Range
to-Surface. surface targets. Complex.
Explosive................. Surface Warfare...... Gunnery Exercise Small boat crews fire medium-caliber guns at E1................... * 404 * 2,828 Virginia Capes Range
Surface-to-Surface surface targets. Complex.
Boat Medium-Caliber.

[[Page 19870]]

Explosive................. Surface Warfare...... Gunnery Exercise Surface ship crews fire large-caliber guns at E3, E5............... * 8 * 56 Gulf Range Complex.
Surface-to-Surface surface targets.
Ship Large-Caliber.
Explosive................. Surface Warfare...... Gunnery Exercise Surface ship crews fire large-caliber guns at E3, E5............... * 46 * 322 Jacksonville Range
Surface-to-Surface surface targets. Complex.
Ship Large-Caliber.
Explosive................. Surface Warfare...... Gunnery Exercise Surface ship crews fire large-caliber guns at E3, E5............... * 34 * 238 Navy Cherry Point
Surface-to-Surface surface targets. Range Complex.
Ship Large-Caliber.
Explosive................. Surface Warfare...... Gunnery Exercise Surface ship crews fire large-caliber guns at E3, E5............... * 9 * 63 Other AFTT Areas.
Surface-to-Surface surface targets.
Ship Large-Caliber.
Explosive................. Surface Warfare...... Gunnery Exercise Surface ship crews fire large-caliber guns at E3, E5............... * 63 *441 Virginia Capes Range
Surface-to-Surface surface targets. Complex.
Ship Large-Caliber.
Explosive................. Surface Warfare...... Integrated Live Fire Naval forces defend against a swarm of surface E10.................. 2 14 Jacksonville Range
Exercise. threats (ships or small boats) with bombs, Complex.
missiles, rockets, and small-, medium- and
large-caliber guns.
Explosive................. Surface Warfare...... Integrated Live Fire Naval forces defend against a swarm of surface E10.................. 2 14 Virginia Capes Range
Exercise. threats (ships or small boats) with bombs, Complex.
missiles, rockets, and small-, medium- and
large-caliber guns.
Explosive................. Surface Warfare...... Missile Exercise Air- Helicopter aircrew fire both precision-guided E3................... 10 70 Gulf Range Complex.
to-Surface--Rocket. and unguided rockets at surface targets.
Explosive................. Surface Warfare...... Missile Exercise Air- Helicopter aircrew fire both precision-guided E3................... 115 805 Jacksonville Range
to-Surface--Rocket. and unguided rockets at surface targets. Complex.
Explosive................. Surface Warfare...... Missile Exercise Air- Helicopter aircrew fire both precision-guided E3................... 15 105 Navy Cherry Point
to-Surface--Rocket. and unguided rockets at surface targets. Range Complex.
Explosive................. Surface Warfare...... Missile Exercise Air- Helicopter aircrew fire both precision-guided E3................... 100 700 Virginia Capes Range
to-Surface--Rocket. and unguided rockets at surface targets. Complex.
Explosive................. Surface Warfare...... Missile Exercise Air- Fixed-wing and helicopter aircrew fire air-to- E6, E8, E9........... 81 567 Jacksonville Range
to-Surface. surface missiles at surface targets. Complex.
Explosive................. Surface Warfare...... Missile Exercise Air- Fixed-wing and helicopter aircrew fire air-to- E6................... 8 56 Key West Range
to-Surface. surface missiles at surface targets. Complex.
Explosive................. Surface Warfare...... Missile Exercise Air- Fixed-wing and helicopter aircrew fire air-to- E6................... 72 504 Navy Cherry Point
to-Surface. surface missiles at surface targets. Range Complex.
Explosive................. Surface Warfare...... Missile Exercise Air- Fixed-wing and helicopter aircrew fire air-to- E6, E8, E9........... 83 581 Virginia Capes Range
to-Surface. surface missiles at surface targets. Complex.
Explosive................. Surface Warfare...... Missile Exercise Surface ship crews defend against surface E6, E9............... 19 133 Jacksonville Range
Surface-to-Surface. threats (ships or small boats) and engage them Complex.
with missiles.
Explosive................. Surface Warfare...... Missile Exercise Surface ship crews defend against surface E6, E9............... 15 105 Virginia Capes Range
Surface-to-Surface. threats (ships or small boats) and engage them Complex.
with missiles.
Acoustic and Explosive.... Surface Warfare...... Sinking Exercise..... Aircraft, ship, cutter, and submarine crews HFH, E5, E8, E9, E11. 1 7 SINKEX Box.
deliberately sink a seaborne target, usually a
decommissioned ship made environmentally safe
for sinking according to U.S. Environmental
Protection Agency standards, with a variety of
ordnance.
Acoustic.................. Other Training Submarine Navigation. Submarine crews operate sonar for navigation MFH.................. 29 203 Jacksonville Range
Activities. and detection while transiting into and out of Complex.
port during reduced visibility.
Acoustic.................. Other Training Submarine Navigation. Submarine crews operate sonar for navigation MFH.................. 169 1,183 Northeast Range
Activities. and detection while transiting into and out of Complexes.
port during reduced visibility.

[[Page 19871]]

Acoustic.................. Other Training Submarine Navigation. Submarine crews operate sonar for navigation MFH.................. 84 588 Virginia Capes Range
Activities. and detection while transiting into and out of Complex, Virginia
port during reduced visibility. Capes Range Complex
Inshore.
Acoustic.................. Other Training Submarine Sonar Maintenance of submarine sonar and other system MFH.................. 4 28 Jacksonville Range
Activities. Maintenance and checks are conducted pierside or at sea. Complex.
Systems Checks.
Acoustic.................. Other Training Submarine Sonar Maintenance of submarine sonar and other system MFH.................. 2 14 Port Canaveral, FL.
Activities. Maintenance and checks are conducted pierside or at sea.
Systems Checks.
Acoustic.................. Other Training Submarine Sonar Maintenance of submarine sonar and other system MFH.................. 2 14 NSB Kings Bay.
Activities. Maintenance and checks are conducted pierside or at sea.
Systems Checks.
Acoustic.................. Other Training Submarine Sonar Maintenance of submarine sonar and other system MFH.................. 66 462 Northeast Range
Activities. Maintenance and checks are conducted pierside or at sea. Complexes.
Systems Checks.
Acoustic.................. Other Training Submarine Sonar Maintenance of submarine sonar and other system MFH.................. 66 462 NSB New London.
Activities. Maintenance and checks are conducted pierside or at sea.
Systems Checks.
Acoustic.................. Other Training Submarine Sonar Maintenance of submarine sonar and other system MFH.................. 12 84 Other AFTT Areas.
Activities. Maintenance and checks are conducted pierside or at sea.
Systems Checks.
Acoustic.................. Other Training Submarine Sonar Maintenance of submarine sonar and other system MFH.................. 34 238 Virginia Capes Range
Activities. Maintenance and checks are conducted pierside or at sea. Complex.
Systems Checks.
Acoustic.................. Other Training Submarine Sonar Maintenance of submarine sonar and other system MFH.................. 34 238 NS Norfolk.
Activities. Maintenance and checks are conducted pierside or at sea.
Systems Checks.
Acoustic.................. Other Training Submarine Under Ice Submarine crews operate sonar while transiting HFH.................. 3 21 Jacksonville Range
Activities. Certification. under ice. Ice conditions are simulated during Complex.
training and certification events.
Acoustic.................. Other Training Submarine Under Ice Submarine crews operate sonar while transiting HFH.................. 3 21 Navy Cherry Point
Activities. Certification. under ice. Ice conditions are simulated during Range Complex.
training and certification events.
Acoustic.................. Other Training Submarine Under Ice Submarine crews operate sonar while transiting HFH.................. 9 63 Northeast Range
Activities. Certification. under ice. Ice conditions are simulated during Complexes.
training and certification events.
Acoustic.................. Other Training Submarine Under Ice Submarine crews operate sonar while transiting HFH.................. 9 63 Virginia Capes Range
Activities. Certification. under ice. Ice conditions are simulated during Complex.
training and certification events.
Acoustic.................. Other Training Surface Ship Sonar Maintenance of surface ship sonar and other MF1, MF1K............ 50 350 Jacksonville Range
Activities. Maintenance and system checks are conducted pierside or at Complex.
Systems Checks. sea.
Acoustic.................. Other Training Surface Ship Sonar Maintenance of surface ship sonar and other MF1, MF1K............ 50 350 NS Mayport.
Activities. Maintenance and system checks are conducted pierside or at
Systems Checks. sea.
Acoustic.................. Other Training Surface Ship Sonar Maintenance of surface ship sonar and other MF1, MF1K............ 120 840 Navy Cherry Point
Activities. Maintenance and system checks are conducted pierside or at Range Complex.
Systems Checks. sea.
Acoustic.................. Other Training Surface Ship Sonar Maintenance of surface ship sonar and other MF1, MF1K............ 175 1,225 NS Norfolk.
Activities. Maintenance and system checks are conducted pierside or at
Systems Checks. sea.
Acoustic.................. Other Training Surface Ship Sonar Maintenance of surface ship sonar and other MF1, MF1K............ 18 126 Other AFTT Areas.
Activities. Maintenance and system checks are conducted pierside or at
Systems Checks. sea.
Acoustic.................. Other Training Surface Ship Sonar Maintenance of surface ship sonar and other MF1, MF1K............ 175 1,225 Virginia Capes Range
Activities. Maintenance and system checks are conducted pierside or at Complex.
Systems Checks. sea.
Acoustic.................. Other Training Unmanned Underwater Unmanned underwater vehicle certification MFH, HFL, HFM, VHFL, 10 70 Gulf Range Complex.
Activities. Vehicle Training-- involves training with unmanned platforms to VHFM, VHFH,
Certification and ensure submarine crew proficiency. Tactical Broadband (MF to
Development. development involves training with various HF), Broadband (HF
payloads, for multiple purposes to ensure that to VHF).
the systems can be employed effectively in an
operational environment.

[[Page 19872]]

Acoustic.................. Other Training Unmanned Underwater Unmanned underwater vehicle certification MFH, HFL, HFM, VHFL, 22 154 Jacksonville Range
Activities. Vehicle Training-- involves training with unmanned platforms to VHFM, VHFH, Complex.
Certification and ensure submarine crew proficiency. Tactical Broadband (MF to
Development. development involves training with various HF), Broadband (HF
payloads, for multiple purposes to ensure that to VHF).
the systems can be employed effectively in an
operational environment.
Acoustic.................. Other Training Unmanned Underwater Unmanned underwater vehicle certification MFH, HFL, HFM, VHFL, 10 70 Navy Cherry Point
Activities. Vehicle Training-- involves training with unmanned platforms to VHFM, VHFH, Range Complex.
Certification and ensure submarine crew proficiency. Tactical Broadband (MF to
Development. development involves training with various HF), Broadband (HF
payloads, for multiple purposes to ensure that to VHF).
the systems can be employed effectively in an
operational environment.
Acoustic.................. Other Training Unmanned Underwater Unmanned underwater vehicle certification MFH, HFL, HFM, VHFL, 12 84 Northeast Range
Activities. Vehicle Training-- involves training with unmanned platforms to VHFM, VHFH, Complexes.
Certification and ensure submarine crew proficiency. Tactical Broadband (MF to
Development. development involves training with various HF), Broadband (HF
payloads, for multiple purposes to ensure that to VHF).
the systems can be employed effectively in an
operational environment.
Acoustic.................. Other Training Unmanned Underwater Unmanned underwater vehicle certification MFH, HFL, HFM, VHFL, 32 224 Virginia Capes Range
Activities. Vehicle Training-- involves training with unmanned platforms to VHFM, VHFH, Complex.
Certification and ensure submarine crew proficiency. Tactical Broadband (MF to
Development. development involves training with various HF), Broadband (HF
payloads, for multiple purposes to ensure that to VHF).
the systems can be employed effectively in an
operational environment.
Acoustic.................. Other Training Unmanned Underwater Unmanned underwater vehicle certification MFH, HFL, HFM, VHFL, 21 147 Virginia Capes Range
Activities. Vehicle Training-- involves training with unmanned platforms to VHFM, VHFH, Complex Inshore.
Certification and ensure submarine crew proficiency. Tactical Broadband (MF to
Development. development involves training with various HF), Broadband (HF
payloads, for multiple purposes to ensure that to VHF).
the systems can be employed effectively in an
operational environment.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: AFTT: Atlantic Fleet Training and Testing; DE: Delaware; FL: Florida; GA: Georgia; JEB: Joint Expeditionary Base; MA: Massachusetts; MS: Mississippi; NC: North Carolina; NJ: New Jersey;
NS: Naval Station; NSB: Naval Submarine Base; SINKEX: Sinking Exercise; TX: Texas; VA: Virginia. The Gulf Range Complex includes geographically separated areas throughout the Gulf of
America.
* Only a small subset of these activities include explosive ordnance.

Table 6--Proposed Coast Guard Training Activities Analyzed Within the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Number of Number of
Stressor category Activity type Activity name Description Source bin activities activities Location
1-year 7-year
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Explosive................. Surface Warfare...... Gunnery Exercise Surface ship crews fire large-caliber guns at E3................... * 29 203 Gulf Range complex.
Surface-to-Surface surface targets.
Ship Large-Caliber.
Explosive................. Surface Warfare...... Gunnery Exercise Surface ship crews fire large-caliber guns at E3................... 15 105 Jacksonville Range
Surface-to-Surface surface targets. Complex.
Ship Large-Caliber.
Explosive................. Surface Warfare...... Gunnery Exercise Surface ship crews fire large-caliber guns at E3................... 10 70 Navy Cherry Point
Surface-to-Surface surface targets. Range Complex.
Ship Large-Caliber.
Explosive................. Surface Warfare...... Gunnery Exercise Surface ship crews fire large-caliber guns at E3................... * 15 105 Northeast Range
Surface-to-Surface surface targets. Complexes.
Ship Large-Caliber.

[[Page 19873]]

Explosive................. Surface Warfare...... Gunnery Exercise Surface ship crews fire large-caliber guns at E3................... * 20 140 Virginia Capes Range
Surface-to-Surface surface targets. Complex.
Ship Large-Caliber.
Acoustic.................. Surface Warfare...... Unmanned Underwater Unmanned underwater vehicle certification MFH, HFL, HFM, VHFL, 10 70 Gulf Range Complex.
Vehicle Training-- involves training with unmanned platforms to VHFM, VHFH,
Certification and ensure submarine crew proficiency. Tactical Broadband (MF to
Development. development involves training with various HF), Broadband (HF
payloads, for multiple purposes to ensure that to VHF).
the systems can be employed effectively in an
operational environment.
Acoustic.................. Surface Warfare...... Unmanned Underwater Unmanned underwater vehicle certification MFH, HFL, HFM, VHFL, 10 70 Jacksonville Range
Vehicle Training-- involves training with unmanned platforms to VHFM, VHFH, Complex.
Certification and ensure submarine crew proficiency. Tactical Broadband (MF to
Development. development involves training with various HF), Broadband (HF
payloads, for multiple purposes to ensure that to VHF).
the systems can be employed effectively in an
operational environment.
Acoustic.................. Surface Warfare...... Unmanned Underwater Unmanned underwater vehicle certification MFH, HFL, HFM, VHFL, 10 70 Navy Cherry Point
Vehicle Training-- involves training with unmanned platforms to VHFM, VHFH, Range Complex.
Certification and ensure submarine crew proficiency. Tactical Broadband (MF to
Development. development involves training with various HF), Broadband (HF
payloads, for multiple purposes to ensure that to VHF).
the systems can be employed effectively in an
operational environment.
Acoustic.................. Surface Warfare...... Unmanned Underwater Unmanned underwater vehicle certification MFH, HFL, HFM, VHFL, 20 140 Virginia Capes Range
Vehicle Training-- involves training with unmanned platforms to VHFM, VHFH, Complex.
Certification and ensure submarine crew proficiency. Tactical Broadband (MF to
Development. development involves training with various HF), Broadband (HF
payloads, for multiple purposes to ensure that to VHF).
the systems can be employed effectively in an
operational environment.
Acoustic.................. Surface Warfare...... Unmanned Underwater Unmanned underwater vehicle certification MFH, HFL, HFM, VHFL, 20 140 Virginia Capes Range
Vehicle Training-- involves training with unmanned platforms to VHFM, VHFH, Complex Inshore.
Certification and ensure submarine crew proficiency. Tactical Broadband (MF to
Development. development involves training with various HF), Broadband (HF
payloads, for multiple purposes to ensure that to VHF).
the systems can be employed effectively in an
operational environment.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: The Gulf Range Complex includes geographically separated areas throughout the Gulf of America.
* Only a small subset of these activities include explosive ordnance.

[[Page 19874]]

Overview of Testing Activities Within the Study Area
While this proposed rule includes an evaluation of proposed
training activities by both the Navy and Coast Guard, all testing
activities evaluated in this proposed rule would only be conducted by
the Navy. The Navy's research and acquisition community engages in a
broad spectrum of testing activities, some of which ultimately support
both Action Proponents. These activities include, but are not limited
to, basic and applied scientific research and technology development;
testing, evaluation, and maintenance of systems (e.g., missiles, radar,
and sonar) and platforms (e.g., surface ships, submarines, and
aircraft); and acquisition of systems and platforms to support Navy
missions and give a technological edge over adversaries. The individual
commands within the research and acquisition community included in the
application are Naval Air Systems Command (NAVAIR), Naval Sea Systems
Command (NAVSEA), and the Office of Naval Research (ONR).
The Action Proponents operate in an ever-changing strategic,
tactical, financially-constrained, and time-constrained environment.
Testing activities occur in response to emerging science or fleet
operational needs. For example, future Navy studies to develop a better
understanding of ocean currents may be designed based on advancements
made by non-government researchers not yet published in the scientific
literature. Similarly, future but yet unknown Navy and Coast Guard
operations within a specific geographic area may require development of
modified Navy assets to address local conditions. Such modifications
must be tested in the field to ensure they meet fleet needs and
requirements. Accordingly, generic descriptions of some of these
activities are the best that can be articulated in a long-term,
comprehensive document.
Some testing activities are similar to training activities
conducted by the fleet (e.g., both the fleet and the research and
acquisition community fire torpedoes). While the firing of a torpedo
might look identical to an observer, the difference is in the purpose
of the firing. The fleet might fire the torpedo to practice the
procedures for such a firing, whereas the research and acquisition
community might be assessing a new torpedo guidance technology or
testing it to ensure the torpedo meets performance specifications and
operational requirements.
NAVAIR testing activities support its mission to provide full life
cycle support of naval aviation aircraft, weapons, and systems to be
operated by the Navy and Coast Guard. NAVAIR activities closely follow
Navy primary mission areas, such as the testing of airborne mine
warfare and anti-submarine warfare weapons and systems. NAVAIR
activities include, but are not limited to, the testing of new aircraft
platforms, weapons, and systems that have not yet been integrated into
the Navy fleet and Coast Guard. In addition to testing new platforms
and weapon systems, most aircraft and weapon systems that have been
integrated into the fleet also require follow-on testing throughout
their lifecycle in conjunction with maintenance and upgrades, such as
software revisions, to ensure that they function as designed. While
these types of activities do not fall within one of the fleet primary
mission areas, most NAVAIR testing activities can be easily correlated
to fleet training activities. Some testing activities may be conducted
in different locations and in a different manner than similar fleet
training activities and, therefore, the analysis for those events and
the potential environmental effects may differ. Table 7 summarizes the
proposed testing activities for NAVAIR analyzed within the AFTT Study
Area.

[[Page 19875]]

Table 7--Proposed NAVAIR Testing Activities Analyzed Within the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Number of Number of
Stressor category Activity type Activity name Description Source bin activities activities Location
1-year 7-year
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Acoustic.................. Anti-Submarine Anti-Submarine The test evaluates the sensors and systems used LFM, LFH, MFM, HFM... 15 105 Gulf Range Complex.
Warfare. Warfare Tracking by fixed-wing aircraft to detect and track
Test (Fixed-Wing). submarines and to ensure that aircraft systems
used to deploy the tracking systems perform to
specifications and meet operational
requirements.
Acoustic.................. Anti-Submarine Anti-Submarine The test evaluates the sensors and systems used LFM, LFH, MFM, HFM... 19 133 Jacksonville Range
Warfare. Warfare Tracking by fixed-wing aircraft to detect and track Complex.
Test (Fixed-Wing). submarines and to ensure that aircraft systems
used to deploy the tracking systems perform to
specifications and meet operational
requirements.
Acoustic.................. Anti-Submarine Anti-Submarine The test evaluates the sensors and systems used LFM, LFH, MFM, HFM... 12 84 Key West Range
Warfare. Warfare Tracking by fixed-wing aircraft to detect and track Complex.
Test (Fixed-Wing). submarines and to ensure that aircraft systems
used to deploy the tracking systems perform to
specifications and meet operational
requirements.
Acoustic.................. Anti-Submarine Anti-Submarine The test evaluates the sensors and systems used LFM, LFH, MFM, HFM... 15 105 Navy Cherry Point
Warfare. Warfare Tracking by fixed-wing aircraft to detect and track Range Complex.
Test (Fixed-Wing). submarines and to ensure that aircraft systems
used to deploy the tracking systems perform to
specifications and meet operational
requirements.
Acoustic.................. Anti-Submarine Anti-Submarine The test evaluates the sensors and systems used LFM, LFH, MFM, HFM... 45 315 Northeast Range
Warfare. Warfare Tracking by fixed-wing aircraft to detect and track Complexes.
Test (Fixed-Wing). submarines and to ensure that aircraft systems
used to deploy the tracking systems perform to
specifications and meet operational
requirements.
Acoustic.................. Anti-Submarine Anti-Submarine The test evaluates the sensors and systems used LFM, LFH, MFM, HFM... 25 175 SINKEX Box.
Warfare. Warfare Tracking by fixed-wing aircraft to detect and track
Test (Fixed-Wing). submarines and to ensure that aircraft systems
used to deploy the tracking systems perform to
specifications and meet operational
requirements.
Acoustic.................. Anti-Submarine Anti-Submarine The test evaluates the sensors and systems used LFM, LFH, MFM, HFM... 25 175 Virginia Capes Range
Warfare. Warfare Tracking by fixed-wing aircraft to detect and track Complex.
Test (Fixed-Wing). submarines and to ensure that aircraft systems
used to deploy the tracking systems perform to
specifications and meet operational
requirements.
Acoustic.................. Anti-Submarine Anti-Submarine This event is similar to the training event HFH.................. 20-43 209 Jacksonville Range
Warfare. Warfare Torpedo Test. torpedo exercise. Test evaluates anti- Complex.
submarine warfare systems onboard rotary-wing
and fixed-wing aircraft and the ability to
search for, detect, classify, localize, track,
and attack a submarine or similar target.
Acoustic.................. Anti-Submarine Anti-Submarine This event is similar to the training event HFH.................. 40-121 523 Virginia Capes Range
Warfare. Warfare Torpedo Test. torpedo exercise. Test evaluates anti- Complex.
submarine warfare systems onboard rotary-wing
and fixed-wing aircraft and the ability to
search for, detect, classify, localize, track,
and attack a submarine or similar target.
Acoustic.................. Anti-Submarine Anti-Submarine This event is similar to the training event MFM, MFH............. 6 42 Gulf Range Complex.
Warfare. Warfare Tracking anti-submarine tracking exercise-helicopter.
Test (Rotary-Wing). The test evaluates the sensors and systems
used to detect and track submarines and to
ensure that helicopter systems used to deploy
the tracking systems perform to
specifications.
Acoustic.................. Anti-Submarine Anti-Submarine This event is similar to the training event MFM, MFH............. 23 161 Jacksonville Range
Warfare. Warfare Tracking anti-submarine tracking exercise-helicopter. Complex.
Test (Rotary-Wing). The test evaluates the sensors and systems
used to detect and track submarines and to
ensure that helicopter systems used to deploy
the tracking systems perform to
specifications.

[[Page 19876]]

Acoustic.................. Anti-Submarine Anti-Submarine This event is similar to the training event MFM, MFH............. 27 189 Key West Range
Warfare. Warfare Tracking anti-submarine tracking exercise-helicopter. Complex.
Test (Rotary-Wing). The test evaluates the sensors and systems
used to detect and track submarines and to
ensure that helicopter systems used to deploy
the tracking systems perform to
specifications.
Acoustic.................. Anti-Submarine Anti-Submarine This event is similar to the training event MFM, MFH............. 110 770 Northeast Range
Warfare. Warfare Tracking anti-submarine tracking exercise-helicopter. Complexes.
Test (Rotary-Wing). The test evaluates the sensors and systems
used to detect and track submarines and to
ensure that helicopter systems used to deploy
the tracking systems perform to
specifications.
Acoustic.................. Anti-Submarine Anti-Submarine This event is similar to the training event MFM, MFH............. 280 1,960 Virginia Capes Range
Warfare. Warfare Tracking anti-submarine tracking exercise-helicopter. Complex.
Test (Rotary-Wing). The test evaluates the sensors and systems
used to detect and track submarines and to
ensure that helicopter systems used to deploy
the tracking systems perform to
specifications.
Acoustic.................. Anti-Submarine Kilo Dip Test........ Functional check of a helicopter deployed MFH.................. 6 42 Gulf Range Complex.
Warfare. dipping sonar system prior to conducting a
testing or training event using the dipping
sonar system.
Acoustic.................. Anti-Submarine Kilo Dip Test........ Functional check of a helicopter deployed MFH.................. 6 42 Jacksonville Range
Warfare. dipping sonar system prior to conducting a Complex.
testing or training event using the dipping
sonar system.
Acoustic.................. Anti-Submarine Kilo Dip Test........ Functional check of a helicopter deployed MFH.................. 6 42 Key West Range
Warfare. dipping sonar system prior to conducting a Complex.
testing or training event using the dipping
sonar system.
Acoustic.................. Anti-Submarine Kilo Dip Test........ Functional check of a helicopter deployed MFH.................. 4 28 Northeast Range
Warfare. dipping sonar system prior to conducting a Complexes.
testing or training event using the dipping
sonar system.
Acoustic.................. Anti-Submarine Kilo Dip Test........ Functional check of a helicopter deployed MFH.................. 40 280 Virginia Capes Range
Warfare. dipping sonar system prior to conducting a Complex.
testing or training event using the dipping
sonar system.
Acoustic and Explosive.... Anti-Submarine Sonobuoy Lot Sonobuoys are deployed from surface vessels and LFM, LFH, MFM, HFM * 186 * 1,302 Key West Range
Warfare. Acceptance Test. aircraft to verify the integrity and E1, E3. Complex.
performance of a lot or group of sonobuoys in
advance of delivery to the fleet for
operational use.
Acoustic.................. Mine Warfare......... Airborne Dipping A mine-hunting dipping sonar system that is HFH.................. 32 224 NSWC Panama City
Sonar Minehunting deployed from a helicopter and uses high- Testing Range.
Test. frequency sonar for the detection and
classification of bottom and moored mines.
Acoustic.................. Mine Warfare......... Airborne Dipping A mine-hunting dipping sonar system that is HFH.................. 40 280 Virginia Capes Range
Sonar Minehunting deployed from a helicopter and uses high- Complex.
Test. frequency sonar for the detection and
classification of bottom and moored mines.
Explosive................. Mine Warfare......... Airborne Mine A test of the airborne mine neutralization E4................... * 27 * 189 NSWC Panama City
Neutralization system evaluates the system's ability to Testing Range.
System Test. detect and destroy mines from an airborne mine
countermeasures capable helicopter. The
airborne mine neutralization system uses up to
four unmanned underwater vehicles equipped
with high-frequency sonar, video cameras, and
explosive and non-explosive neutralizers.

[[Page 19877]]

Explosive................. Mine Warfare......... Airborne Mine A test of the airborne mine neutralization E4................... * 25 * 175 Virginia Capes Range
Neutralization system evaluates the system's ability to Complex.
System Test. detect and destroy mines from an airborne mine
countermeasures capable helicopter. The
airborne mine neutralization system uses up to
four unmanned underwater vehicles equipped
with high-frequency sonar, video cameras, and
explosive and non-explosive neutralizers.
Acoustic.................. Mine Warfare......... Airborne Minehunting A mine-hunting system made up of sonobuoys is MFM.................. 26 182 NSWC Panama City
Test--Sonobuoy. deployed from a helicopter. A field of Testing Range.
sonobuoys, using high-frequency sonar, is used
for detection and classification of bottom and
moored mines.
Acoustic.................. Mine Warfare......... Airborne Minehunting A mine-hunting system made up of sonobuoys is MFM.................. 12 84 Virginia Capes Range
Test--Sonobuoy. deployed from a helicopter. A field of Complex.
sonobuoys, using high-frequency sonar, is used
for detection and classification of bottom and
moored mines.
Explosive................. Surface Warfare...... Air-to-Surface This event is similar to the training event E1................... 55 385 Jacksonville Range
Gunnery Test. gunnery exercise air-to-surface. Fixed-wing Complex.
and rotary-wing aircrew evaluate new or
enhanced aircraft guns against surface
maritime targets to test that the gun, gun
ammunition, or associated systems meet
required specifications or to train aircrew in
the operation of a new or enhanced weapons
system.
Explosive................. Surface Warfare...... Air-to-Surface This event is similar to the training event E1................... 140 980 Virginia Capes Range
Gunnery Test. gunnery exercise air-to-surface. Fixed-wing Complex.
and rotary-wing aircrew evaluate new or
enhanced aircraft guns against surface
maritime targets to test that the gun, gun
ammunition, or associated systems meet
required specifications or to train aircrew in
the operation of a new or enhanced weapons
system.
Explosive................. Surface Warfare...... Air-to-Surface This event is similar to the training event E9................... 5 35 Gulf Range Complex.
Missile Test. missile exercise air-to-surface. Test may
involve both fixed-wing and rotary-wing
aircraft launching missiles at surface
maritime targets to evaluate the weapons
system or as part of another systems
integration test.
Explosive................. Surface Warfare...... Air-to-Surface This event is similar to the training event E6................... * 29 * 203 Jacksonville Range
Missile Test. missile exercise air-to-surface. Test may Complex.
involve both fixed-wing and rotary-wing
aircraft launching missiles at surface
maritime targets to evaluate the weapons
system or as part of another systems
integration test.
Explosive................. Surface Warfare...... Air-to-Surface This event is similar to the training event E6................... * 117 * 819 Virginia Capes Range
Missile Test. missile exercise air-to-surface. Test may Complex.
involve both fixed-wing and rotary-wing
aircraft launching missiles at surface
maritime targets to evaluate the weapons
system or as part of another systems
integration test.
Explosive................. Surface Warfare...... Rocket Test.......... Rocket tests are conducted to evaluate the E3................... 19 133 Jacksonville Range
integration, accuracy, performance, and safe Complex.
separation of guided and unguided 2.75-inch
rockets fired from a hovering or forward
flying helicopter or tilt rotor aircraft.
Explosive................. Surface Warfare...... Rocket Test.......... Rocket tests are conducted to evaluate the E3................... * 35 * 245 Virginia Capes Range
integration, accuracy, performance, and safe Complex.
separation of guided and unguided 2.75-inch
rockets fired from a hovering or forward
flying helicopter or tilt rotor aircraft.

[[Page 19878]]

Acoustic.................. Other Testing Undersea Range System Following installation of a Navy underwater MFM, HFM............. 4-20 76 Jacksonville Range
Activities. Test. warfare training and testing range, tests of Complex.
the nodes (components of the range) will be
conducted to include node surveys and testing
of node transmission functionality.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: NAVAIR: Naval Air Systems Command; NSWC: Naval Surface Warfare Center. The Gulf Range Complex includes geographically separated areas throughout the Gulf of America.
* Only a small subset of these activities include explosive ordnance.

[[Page 19879]]

NAVSEA activities are aligned with its mission of new ship
construction, life cycle management, and weapon systems development.
NAVSEA activities include pierside and at-sea testing of vessel
systems, including sonar, acoustic countermeasures, radars, launch
systems, weapons, unmanned systems, and radio equipment; tests to
determine how the vessel or Coast Guard Cutter performs at sea (sea
trials); developmental and operational test and evaluation programs for
new technologies and systems; and testing on all vessels and systems
that have undergone overhaul or maintenance. In the application,
pierside testing at Navy contractor shipyards would consist only of
system testing. At-sea test firing of shipboard weapon systems,
including guns, torpedoes, and missiles, is also conducted. Testing
activities are conducted throughout the life of a vessel, from
construction to verification of performance and mission capabilities,
and further to deactivation from the fleet. Table 8 summarizes the
proposed testing activities for the NAVSEA analyzed within the AFTT
Study Area.
One ship of each new class (or major upgrade) of combat ships
constructed for the Navy typically undergoes an at-sea ship shock
trial. A ship shock trial consists of a series of underwater
detonations that send shock waves through the ship's hull to simulate
near misses during combat. A shock trial allows the Navy to assess the
survivability of the hull and ship's systems in a combat environment as
well as the capability of the ship to protect the crew.

[[Page 19880]]

Table 8--Proposed NAVSEA Testing Activities Analyzed Within the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Number of Number of
Stressor category Activity type Activity name Description Source bin activities activities Location
1-year 7-year
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Acoustic.................. Anti-Submarine Anti-Submarine Ships and their supporting platforms (e.g., MFH, MF1............. 1-2 11 Gulf Range Complex.
Warfare. Warfare Mission rotary-wing aircraft and unmanned aerial
Package Testing. systems) detect, localize, and prosecute
submarines.
Acoustic.................. Anti-Submarine Anti-Submarine Ships and their supporting platforms (e.g., MFH, MF1............. 2 14 Jacksonville Range
Warfare. Warfare Mission rotary-wing aircraft and unmanned aerial Complex.
Package Testing. systems) detect, localize, and prosecute
submarines.
Acoustic.................. Anti-Submarine Anti-Submarine Ships and their supporting platforms (e.g., MFH, MF1............. 1-2 11 Northeast Range
Warfare. Warfare Mission rotary-wing aircraft and unmanned aerial Complexes.
Package Testing. systems) detect, localize, and prosecute
submarines.
Acoustic.................. Anti-Submarine At-Sea Sonar Testing. At-sea testing to ensure systems are fully MFL, MFM, MFH, MF1, 7-9 49 Gulf Range Complex;
Warfare. functional in an open ocean environment. MF1K, HFL, HFM, HFH, Jacksonville Range
Broadband (LF to Complex; Navy
HF), Broadband (LF Cherry Point Range
to MF), Broadband Complex; Northeast
(MF to HF). Range Complexes;
SFOMF; Virginia
Capes Range
Complex.
Acoustic.................. Anti-Submarine At-Sea Sonar Testing. At-sea testing to ensure systems are fully MFL, MFM, MFH, MF1, 7-14 77 Gulf Range Complex.
Warfare. functional in an open ocean environment. MF1K, HFL, HFM, HFH,
Broadband (LF to
HF), Broadband (LF
to MF), Broadband
(MF to HF).
Acoustic.................. Anti-Submarine At-Sea Sonar Testing. At-sea testing to ensure systems are fully MFL, MFM, MFH, MF1, 4 28 Jacksonville Range
Warfare. functional in an open ocean environment. MF1K, HFL, HFM, HFH, Complex.
Broadband (LF to
HF), Broadband (LF
to MF), Broadband
(MF to HF).
Acoustic.................. Anti-Submarine At-Sea Sonar Testing. At-sea testing to ensure systems are fully MFL, MFM, MFH, MF1, 2 14 Navy Cherry Point
Warfare. functional in an open ocean environment. MF1K, HFL, HFM, HFH, Range Complex.
Broadband (LF to
HF), Broadband (LF
to MF), Broadband
(MF to HF).
Acoustic.................. Anti-Submarine At-Sea Sonar Testing. At-sea testing to ensure systems are fully MFL, MFM, MFH, MF1, 8-15 84 Northeast Range
Warfare. functional in an open ocean environment. MF1K, HFL, HFM, HFH, Complexes.
Broadband (LF to
HF), Broadband (LF
to MF), Broadband
(MF to HF).

[[Page 19881]]

Acoustic.................. Anti-Submarine At-Sea Sonar Testing. At-sea testing to ensure systems are fully MFL, MFM, MFH, MF1, 16-22 58 Virginia Capes Range
Warfare. functional in an open ocean environment. MF1K, HFL, HFM, HFH, Complex.
Broadband (LF to
HF), Broadband (LF
to MF), Broadband
(MF to HF).
Acoustic.................. Anti-Submarine At-Sea Sonar Testing. At-sea testing to ensure systems are fully MFL, MFM, MFH, MF1, 2 14 SFOMF.
Warfare. functional in an open ocean environment. MF1K, HFL, HFM, HFH,
Broadband (LF to
HF), Broadband (LF
to MF), Broadband
(MF to HF).
Acoustic.................. Anti-Submarine Pierside Sonar Pierside testing to ensure systems are fully MFM, MFH, HFM, HFH, 5-10 64 NSB New London; Gulf
Warfare. Testing. functional in a controlled pierside Broadband (MF to HF). Range Complex
environment prior to at-sea test activities Inshore;
and complete any required troubleshooting. Jacksonville Range
Complex; NSB Kings
Bay; Newport, RI;
NS Norfolk;
Northeast Range
Complexes; Port
Canaveral, FL;
Virginia Capes
Range Complex.
Acoustic.................. Anti-Submarine Pierside Sonar Pierside testing to ensure systems are fully MFM, MFH, HFM, HFH, 10-20 110 Bath, ME.
Warfare. Testing. functional in a controlled pierside Broadband (MF to HF).
environment prior to at-sea test activities
and complete any required troubleshooting.
Acoustic.................. Anti-Submarine Pierside Sonar Pierside testing to ensure systems are fully MFM, MFH, HFM, HFH, 10-18 94 NS Mayport.
Warfare. Testing. functional in a controlled pierside Broadband (MF to HF).
environment prior to at-sea test activities
and complete any required troubleshooting.
Acoustic.................. Anti-Submarine Pierside Sonar Pierside testing to ensure systems are fully MFM, MFH, HFM, HFH, 63-84 455 NS Norfolk.
Warfare. Testing. functional in a controlled pierside Broadband (MF to HF).
environment prior to at-sea test activities
and complete any required troubleshooting.
Acoustic.................. Anti-Submarine Pierside Sonar Pierside testing to ensure systems are fully MFM, MFH, HFM, HFH, 10-20 110 Pascagoula, MS.
Warfare. Testing. functional in a controlled pierside Broadband (MF to HF).
environment prior to at-sea test activities
and complete any required troubleshooting.
Acoustic.................. Anti-Submarine Pierside Sonar Pierside testing to ensure systems are fully MFM, MFH, HFM, HFH, 16-24 152 Portsmouth Naval
Warfare. Testing. functional in a controlled pierside Broadband (MF to HF). Shipyard.
environment prior to at-sea test activities
and complete any required troubleshooting.
Acoustic.................. Anti-Submarine Surface Ship Sonar Pierside and at-sea testing of ship systems LFL, MFM, MF1, MF1K, 1 7 Jacksonville Range
Warfare. Testing/Maintenance. occurs periodically following major Broadband (MF to HF). Complex.
maintenance periods and for routine
maintenance.
Acoustic.................. Anti-Submarine Surface Ship Sonar Pierside and at-sea testing of ship systems LFL, MFM, MF1, MF1K, 4 28 Virginia Capes Range
Warfare. Testing/Maintenance. occurs periodically following major Broadband (MF to HF). Complex.
maintenance periods and for routine
maintenance.
Acoustic and Explosive.... Anti-Submarine Torpedo (Explosive) Air, surface, or submarine crews employ MFM, MFH, MF1, HFH, 1-5 17 Gulf Range Complex;
Warfare. Testing. explosive and non-explosive torpedoes against Broadband (MF to Jacksonville Range
artificial targets. HF), E8, E11. Complex; Key West
Range Complex; Navy
Cherry Point Range
Complex; Northeast
Range Complexes;
Virginia Capes
Range Complex.

[[Page 19882]]

Acoustic.................. Anti-Submarine Torpedo (Non- Air, surface, or submarine crews employ non- MFL, MFM, MFH, MF1, 13-17 82 Gulf Range Complex;
Warfare. Explosive) Testing. explosive torpedoes against targets, HFM, HFH, VHFH, Jacksonville Range
submarines, or surface vessels. Broadband (LF to Complex; Key West
HF), Broadband (MF Range Complex; Navy
to HF). Cherry Point Range
Complex; Northeast
Range Complexes;
SFOMF; Virginia
Capes Range
Complex.
Acoustic.................. Anti-Submarine Torpedo (Non- Air, surface, or submarine crews employ non- MFL, MFM, MFH, MF1, 30 210 NUWC Newport Testing
Warfare. Explosive) Testing. explosive torpedoes against targets, HFM, HFH, VHFH, Range.
submarines, or surface vessels. Broadband (LF to
HF), Broadband (MF
to HF).
Explosive................. Mine Warfare......... Mine Countermeasure Air, surface, and subsurface vessels neutralize E4................... 18-45 315 Gulf Range Complex.
and Neutralization threat mines and mine-like objects.
Testing.
Explosive................. Mine Warfare......... Mine Countermeasure Air, surface, and subsurface vessels neutralize E4................... * 24-48 * 288 Virginia Capes Range
and Neutralization threat mines and mine-like objects. Complex.
Testing.
Acoustic.................. Mine Warfare......... Mine Countermeasure Vessels and associated aircraft conduct mine MFH, HFM, HFH........ 15 105 Gulf Range Complex.
Mission Package countermeasure operations.
Testing.
Acoustic.................. Mine Warfare......... Mine Countermeasure Vessels and associated aircraft conduct mine MFH, HFM, HFH........ 8 56 Jacksonville Range
Mission Package countermeasure operations. Complex.
Testing.
Acoustic.................. Mine Warfare......... Mine Countermeasure Vessels and associated aircraft conduct mine MFH, HFM, HFH........ 11 77 NSWC Panama City
Mission Package countermeasure operations. Testing Range.
Testing.
Acoustic.................. Mine Warfare......... Mine Countermeasure Vessels and associated aircraft conduct mine MFH, HFM, HFH........ 2 14 SFOMF.
Mission Package countermeasure operations.
Testing.
Acoustic.................. Mine Warfare......... Mine Countermeasure Vessels and associated aircraft conduct mine MFH, HFM, HFH........ 3 21 Virginia Capes Range
Mission Package countermeasure operations. Complex.
Testing.
Acoustic.................. Mine Warfare......... Mine Detection and Air, surface, and subsurface vessels and HFH.................. 0-1 1 Jacksonville Range
Classification systems detect and classify mines and mine- Complex, NSWC
Testing. like objects. Vessels also assess their Panama City Testing
potential susceptibility to mines and mine- Range, Port
like objects. Canaveral, FL.
Acoustic.................. Mine Warfare......... Mine Detection and Air, surface, and subsurface vessels and HFH.................. 0-1 4 Jacksonville Range
Classification systems detect and classify mines and mine- Complex.
Testing. like objects. Vessels also assess their
potential susceptibility to mines and mine-
like objects.
Acoustic.................. Mine Warfare......... Mine Detection and Air, surface, and subsurface vessels and HFH.................. 286-287 2,005 NSWC Panama City
Classification systems detect and classify mines and mine- Testing Range.
Testing. like objects. Vessels also assess their
potential susceptibility to mines and mine-
like objects.
Acoustic and Explosive.... Acoustic and Acoustic and Research using active transmissions from LFM, Broadband (LF to 0-1 1 Gulf Range Complex;
Oceanographic Oceanographic sources deployed from ships, aircraft, and HF), E7. Jacksonville Range
Science and Research. unmanned underwater vehicles. Research sources Complex; Key West
Technology. can be used as proxies for current and future Range Complex.
Navy systems.
Acoustic.................. Other Testing Acoustic and Research using active transmissions from LFM, Broadband (LF to 3 21 Northeast Range
Activities. Oceanographic sources deployed from ships, aircraft, and HF). Complexes.
Research. unmanned underwater vehicles. Research sources
can be used as proxies for current and future
Navy systems.
Acoustic and Explosive.... Other Testing Acoustic and Research using active transmissions from LFM, Broadband (LF to * 0-1 * 3 Key West Range
Activities. Oceanographic sources deployed from ships, aircraft, and HF), E7. Complex.
Research. unmanned underwater vehicles. Research sources
can be used as proxies for current and future
Navy systems.

[[Page 19883]]

Acoustic.................. Other Testing Acoustic and Research using active transmissions from LFM, Broadband (LF to 0-1 2 Other AFTT Areas.
Activities. Oceanographic sources deployed from ships, aircraft, and HF).
Research. unmanned underwater vehicles. Research sources
can be used as proxies for current and future
Navy systems.
Acoustic.................. Other Testing Acoustic Component Various surface vessels, moored equipment, and LFL, MFL, MFH, HFM, 33 231 SFOMF.
Activities. Testing. materials are tested to evaluate performance HFH, VHFH, Broadband
in the marine environment. (LF to HF),
Broadband (MF to HF).
Acoustic.................. Other Testing Acoustic Component Various surface vessels, moored equipment, and LFL, MFL, MFH, HFM, 1 7 Jacksonville Range
Activities. Testing. materials are tested to evaluate performance HFH, VHFH, Broadband Complex.
in the marine environment. (LF to HF),
Broadband (MF to HF).
Acoustic.................. Other Testing Countermeasure Countermeasure testing involves the testing of MFM, MFH, HFH, VHFH, 16-20 116 Gulf Range Complex;
Activities. Testing. systems that will detect, localize, track, and Broadband (LF to Jacksonville Range
engage incoming weapons, including marine HF), Broadband (MF Complex; Key West
vessel targets and airborne missiles. Testing to HF). Range Complex; Navy
includes surface ship torpedo defense systems, Cherry Point Range
marine vessel stopping payloads, and airborne Complex; Northeast
decoys against air targets. Range Complexes;
Virginia Capes
Range Complex; JEB
Little Creek Fort
Story.
Acoustic.................. Other Testing Countermeasure Countermeasure testing involves the testing of MFM, MFH, HFH, VHFH, 8-10 63 Gulf Range Complex.
Activities. Testing. systems that will detect, localize, track, and Broadband (LF to
engage incoming weapons, including marine HF), Broadband (MF
vessel targets and airborne missiles. Testing to HF).
includes surface ship torpedo defense systems,
marine vessel stopping payloads, and airborne
decoys against air targets.
Acoustic.................. Other Testing Countermeasure Countermeasure testing involves the testing of MFM, MFH, HFH, VHFH, 6 42 NUWC Newport Testing
Activities. Testing. systems that will detect, localize, track, and Broadband (LF to Range.
engage incoming weapons, including marine HF), Broadband (MF
vessel targets and airborne missiles. Testing to HF).
includes surface ship torpedo defense systems,
marine vessel stopping payloads, and airborne
decoys against air targets.
Acoustic.................. Other Testing Countermeasure Countermeasure testing involves the testing of MFM, MFH, HFH, VHFH, 6-10 13 Virginia Capes Range
Activities. Testing. systems that will detect, localize, track, and Broadband (LF to Complex.
engage incoming weapons, including marine HF), Broadband (MF
vessel targets and airborne missiles. Testing to HF).
includes surface ship torpedo defense systems,
marine vessel stopping payloads, and airborne
decoys against air targets.
Acoustic.................. Other Testing Insertion/Extraction. Testing of submersibles capable of inserting LFH, HFM, Broadband 501-502 3,514 Key West Range
Activities. and extracting personnel and payloads into (LF to MF). Complex; NSWC
denied areas from strategic distances. Panama City Testing
Range.
Explosive................. Other Testing Line Charge Testing.. Surface vessels deploy line charges to test the E4................... 4 28 NSWC Panama City
Activities. capability to safely clear an area for Testing Range.
expeditionary forces.
Acoustic and Explosive.... Other Testing Semi-Stationary Semi-stationary equipment (e.g., hydrophones) AG230, HFH, HFM, * 8-14 * 74 NSB New London;NS
Activities. Equipment Testing. is deployed to determine functionality. Broadband (LF), Mayport; NS
Broadband (LF to Norfolk; Port
HF), Broadband (MF Canaveral, FL;
to HF), MFM, VHFH, Virginia Capes
VHFM, E4. Range Complex
Inshore; Key West
Range Complex
Inshore.

[[Page 19884]]

Acoustic and Explosive.... Other Testing Semi-Stationary Semi-stationary equipment (e.g., hydrophones) AG230, HFH, HFM, 4 28 Newport, RI.
Activities. Equipment Testing. is deployed to determine functionality. Broadband (LF),
Broadband (LF to
HF), Broadband (MF
to HF), MFM, VHFH,
VHFM, E4.
Acoustic and Explosive.... Other Testing Semi-Stationary Semi-stationary equipment (e.g., hydrophones) AG230, HFH, HFM, 30 210 NSWC Panama City
Activities. Equipment Testing. is deployed to determine functionality. Broadband (LF), Testing Range.
Broadband (LF to
HF), Broadband (MF
to HF), MFM, VHFH,
VHFM, E4.
Acoustic and Explosive.... Other Testing Semi-Stationary Semi-stationary equipment (e.g., hydrophones) AG230, HFH, HFM, * 155-173 * 1,139 NUWC Newport Testing
Activities. Equipment Testing. is deployed to determine functionality. Broadband (LF), Range.
Broadband (LF to
HF), Broadband (MF
to HF), MFM, VHFH,
VHFM, E4.
Acoustic.................. Other Testing Towed Equipment Surface vessels or unmanned surface vehicles MFM, Broadband (LF).. 43-49 319 NUWC Newport Testing
Activities. Testing. deploy and tow equipment to determine Range.
functionality of towed systems.
Explosive................. Surface Warfare...... Gun Testing--Large- Surface crews test large-caliber guns to defend E3, E5............... * 1-15 * 20 Jacksonville Range
Caliber. against surface targets. Demonstration of Complex; Virginia
large-caliber guns including the MK 45 5-inch Capes Range
gun and MK 41 Vertical Launch Systems using Complex.
surface to air missiles.
Explosive................. Surface Warfare...... Gun Testing--Large- Surface crews test large-caliber guns to defend E3, E5............... 1-2 11 Gulf Range Complex.
Caliber. against surface targets. Demonstration of
large-caliber guns including the MK 45 5-inch
gun and MK 41 Vertical Launch Systems using
surface to air missiles.
Explosive................. Surface Warfare...... Gun Testing--Large- Surface crews test large-caliber guns to defend E3, E5............... * 2-4 * 23 Jacksonville Range
Caliber. against surface targets. Demonstration of Complex.
large-caliber guns including the MK 45 5-inch
gun and MK 41 Vertical Launch Systems using
surface to air missiles.
Explosive................. Surface Warfare...... Gun Testing--Large- Surface crews test large-caliber guns to defend E3, E5............... 1-2 11 Northeast Range
Caliber. against surface targets. Demonstration of Complexes.
large-caliber guns including the MK 45 5-inch
gun and MK 41 Vertical Launch Systems using
surface to air missiles.
Explosive................. Surface Warfare...... Gun Testing--Large- Surface crews test large-caliber guns to defend E3, E5............... * 15 * 105 NSWC Panama City
Caliber. against surface targets. Demonstration of Testing Range.
large-caliber guns including the MK 45 5-inch
gun and MK 41 Vertical Launch Systems using
surface to air missiles.

[[Page 19885]]

Explosive................. Surface Warfare...... Missile and Rocket Missile and rocket testing includes various E6, E7, E8, E10...... * 6-18 * 49 Gulf Range Complex;
Testing. missiles or rockets fired from submarines and Jacksonville Range
surface combatants. Testing of the launching Complex; Navy
system and ship defense is performed. Cherry Point Range
Complex; Virginia
Capes Range
Complex.
Explosive................. Surface Warfare...... Missile and Rocket Missile and rocket testing includes various E6, E7, E8, E10...... * 20-30 * 78 Virginia Capes Range
Testing. missiles or rockets fired from submarines and Complex.
surface combatants. Testing of the launching
system and ship defense is performed.
Acoustic.................. Unmanned Systems..... Unmanned Underwater Testing involves the production or upgrade of LFL, MFL, MFM, MFH, 208-209 1,459 NSWC Panama City
Vehicle Testing. unmanned underwater vehicles. This may include HFM, HFH, VHFH, Testing Range.
testing of mine detection capabilities, Broadband (LF to
evaluating the basic functions of individual HF), Broadband (MF
platforms, or complex events with multiple to HF).
vehicles.
Acoustic.................. Unmanned Systems..... Unmanned Underwater Testing involves the production or upgrade of LFL, MFL, MFM, MFH, 138 966 NUWC Newport Testing
Vehicle Testing. unmanned underwater vehicles. This may include HFM, HFH, VHFH, Range.
testing of mine detection capabilities, Broadband (LF to
evaluating the basic functions of individual HF), Broadband (MF
platforms, or complex events with multiple to HF).
vehicles.
Acoustic.................. Unmanned Systems..... Unmanned Underwater Testing involves the production or upgrade of LFL, MFL, MFM, MFH, 1 7 SFOMF.
Vehicle Testing. unmanned underwater vehicles. This may include HFM, HFH, VHFH,
testing of mine detection capabilities, Broadband (LF to
evaluating the basic functions of individual HF), Broadband (MF
platforms, or complex events with multiple to HF).
vehicles.
Acoustic.................. Vessel Evaluation.... In-Port Maintenance Each combat system is tested to ensure they are MF1.................. 2 4 NS Mayport; NS
Testing. functioning in a technically acceptable manner Norfolk.
and are operationally ready to support at-sea
testing.
Acoustic.................. Vessel Evaluation.... In-Port Maintenance Each combat system is tested to ensure they are MF1.................. 2 14 NS Mayport.
Testing. functioning in a technically acceptable manner
and are operationally ready to support at-sea
testing.
Acoustic.................. Vessel Evaluation.... In-Port Maintenance Each combat system is tested to ensure they are MF1.................. 4 28 NS Norfolk.
Testing. functioning in a technically acceptable manner
and are operationally ready to support at-sea
testing.
Acoustic.................. Vessel Evaluation.... Signature Analysis Surface ship and submarine testing of LFM, LFH, MFM, HFM, 0-1 4 Hampton Roads, VA.
Operations. electromagnetic, acoustic, optical, and radar Broadband (LF).
signature measurements.
Acoustic.................. Vessel Evaluation.... Signature Analysis Surface ship and submarine testing of LFM, LFH, MFM, HFM, 79-94 579 SFOMF.
Operations. electromagnetic, acoustic, optical, and radar Broadband (LF).
signature measurements.
Explosive................. Vessel Evaluation.... Small Ship Shock Underwater detonations are used to test new E16.................. 0-2 5 Jacksonville Range
Trial. ships or major upgrades. Complex; Gulf Range
Complex.
Acoustic.................. Vessel Evaluation.... Submarine Sea Trials-- Submarine weapons and sonar systems are tested MFL, MFH, HFM, HFH, 3-7 22 Gulf Range Complex;
Weapons System at-sea to meet the integrated combat system Broadband (LF to HF). Jacksonville Range
Testing. certification requirements. Complex; NSB Kings
Bay; Northeast
Range Complexes;
Port Canaveral, FL;
Virginia Capes
Range Complex.
Acoustic.................. Vessel Evaluation.... Submarine Sea Trials-- Submarine weapons and sonar systems are tested MFL, MFH, HFM, HFH, 2-4 28 Northeast Range
Weapons System at-sea to meet the integrated combat system Broadband (LF to HF). Complexes.
Testing. certification requirements.
Acoustic.................. Vessel Evaluation.... Submarine Sea Trials-- Submarine weapons and sonar systems are tested MFL, MFH, HFM, HFH, 1 6 Northeast Range
Weapons System at-sea to meet the integrated combat system Broadband (LF to HF). Complexes Inshore.
Testing. certification requirements.

[[Page 19886]]

Acoustic.................. Vessel Evaluation.... Submarine Sea Trials-- Submarine weapons and sonar systems are tested MFL, MFH, HFM, HFH, 2-4 28 Virginia Capes Range
Weapons System at-sea to meet the integrated combat system Broadband (LF to HF). Complex.
Testing. certification requirements.
Acoustic and Explosive.... Vessel Evaluation.... Surface Warfare Tests the capabilities of shipboard sensors to HFH, E3, E5, E6, E7, * 17-76 * 206 Jacksonville Range
Testing. detect, track, and engage surface targets. E8. Complex; Virginia
Testing may include ships defending against Capes Range
surface targets using explosive and non- Complex.
explosive rounds, gun system structural test
firing and demonstration of the response to
Call for Fire against land-based targets
(simulated by sea-based locations).
Acoustic.................. Vessel Evaluation.... Surface Warfare Tests the capabilities of shipboard sensors to HFH.................. 0-2 6 Gulf Range Complex.
Testing. detect, track, and engage surface targets.
Testing may include ships defending against
surface targets using non-explosive rounds,
gun system structural test firing and
demonstration of the response to Call for Fire
against land-based targets (simulated by sea-
based locations).
Acoustic and Explosive.... Vessel Evaluation.... Surface Warfare Tests the capabilities of shipboard sensors to HFH, E3, E5, E6, E7, * 4-6 * 37 Jacksonville Range
Testing. detect, track, and engage surface targets. E8. Complex.
Testing may include ships defending against
surface targets using explosive and non-
explosive rounds, gun system structural test
firing and demonstration of the response to
Call for Fire against land-based targets
(simulated by sea-based locations).
Acoustic and Explosive.... Vessel Evaluation.... Surface Warfare Tests the capabilities of shipboard sensors to HFH, E3, E5, E6, E7, * 5-7 * 42 Virginia Capes Range
Testing. detect, track, and engage surface targets. E8. Complex.
Testing may include ships defending against
surface targets using explosive and non-
explosive rounds, gun system structural test
firing and demonstration of the response to
Call for Fire against land-based targets
(simulated by sea-based locations).
Acoustic and Explosive.... Vessel Evaluation.... Undersea Warfare Ships demonstrate capability of countermeasure MFM, MFH, MF1, HFM, 6-24 105 Jacksonville Range
Testing. systems and underwater surveillance, weapons HFH, Broadband (LF Complex; Navy
engagement and communications systems. This to HF), E4. Cherry Point Range
tests ships ability to detect, track, and Complex; Northeast
engage undersea targets. Range Complexes;
SFOMF; Virginia
Capes Range
Complex.
Acoustic and Explosive.... Vessel Evaluation.... Undersea Warfare Ships demonstrate capability of countermeasure MFM, MFH, MF1, HFM, * 4-6 * 30 Jacksonville Range
Testing. systems and underwater surveillance, weapons HFH, Broadband (LF Complex.
engagement and communications systems. This to HF), E4.
tests ships ability to detect, track, and
engage undersea targets.
Acoustic.................. Vessel Evaluation.... Vessel Signature Surface ship, submarine, and auxiliary system MFM, HFM, HFH........ 1-4 9 Jacksonville Range
Evaluation. signature assessments. This may include Complex; Virginia
electronic, radar, acoustic, infrared and Capes Range
magnetic signatures. Complex.
Acoustic.................. Vessel Evaluation.... Vessel Signature Surface ship, submarine, and auxiliary system MFM, HFM, HFH........ 0-1 2 Gulf Range Complex.
Evaluation. signature assessments. This may include
electronic, radar, acoustic, infrared and
magnetic signatures.
Acoustic.................. Vessel Evaluation.... Vessel Signature Surface ship, submarine, and auxiliary system MFM, HFM, HFH........ 1-3 6 Hampton Roads, VA.
Evaluation. signature assessments. This may include
electronic, radar, acoustic, infrared and
magnetic signatures.

[[Page 19887]]

Acoustic.................. Vessel Evaluation.... Vessel Signature Surface ship, submarine, and auxiliary system MFM, HFM, HFH........ 0-1 3 NUWC Newport Testing
Evaluation. signature assessments. This may include Range.
electronic, radar, acoustic, infrared and
magnetic signatures.
Acoustic.................. Vessel Evaluation.... Vessel Signature Surface ship, submarine, and auxiliary system MFM, HFM, HFH........ 0-1 3 SFOMF.
Evaluation. signature assessments. This may include
electronic, radar, acoustic, infrared and
magnetic signatures.
Acoustic.................. Vessel Evaluation.... Vessel Signature Surface ship, submarine, and auxiliary system MFM, HFM, HFH........ 0-1 4 Virginia Capes Range
Evaluation. signature assessments. This may include Complex.
electronic, radar, acoustic, infrared and
magnetic signatures.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: FL: Florida; GA: Georgia; JEB: Joint Expeditionary Base; LA: Louisiana; MS: Mississippi; NS: Naval Station; NSB: Naval Submarine Base; NSWC: Naval Surface Warfare Center; NUWC: Naval
Undersea Warfare Center; RI: Rhode Island; SFOMF: South Florida Ocean Measurement Facility; VA: Virginia. The Gulf Range Complex and Gulf Range Complex Inshore includes geographically
separated areas throughout the Gulf of America.
* Only a small subset of these activities include explosive ordnance.

[[Page 19888]]

The ONR, as the Department of the Navy's science and technology
provider, provides technology solutions for Navy and Marine Corps
needs. The ONR's mission, defined by law, is to plan, foster, and
encourage scientific research in recognition of its paramount
importance as related to the maintenance of future naval power and the
preservation of national security. The ONR manages the Navy's basic,
applied, and advanced research to foster transition from science and
technology to higher levels of research, development, test, and
evaluation. The ONR is also a parent organization for the Naval
Research Laboratory, which operates as the Navy's corporate research
laboratory and conducts a broad multidisciplinary program of scientific
research and advanced technological development. Testing activities
conducted by the ONR and the Naval Research Laboratory include
activities such as acoustic and oceanographic research, UUV research,
and next generation mine countermeasures research. Table 9 summarizes
the proposed testing activities for the ONR analyzed within the AFTT
Study Area.

[[Page 19889]]

Table 9--Proposed ONR Testing Activities Analyzed Within the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Number of Number of
Stressor category Activity type Activity name Description Source bin activities activities Location
1-year 7-year
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Acoustic and Explosive.... Acoustic and Acoustic and Research using active transmissions from LFM, LFH, MFM, MFH, * 12-15 * 93 Gulf Range Complex;
Oceanographic Oceanographic sources deployed from ships, aircraft, and HFM, HFH, E1, E3, Jacksonville Range
Science and Research. unmanned vehicles. Research sources can be 3S3, AG232. Complex; Northeast
Technology. used as proxies for current and future Navy Range Complexes;
systems. Virginia Capes
Range Complex.
Acoustic.................. Acoustic and Mine Countermeasure Test involves the use of broadband acoustic MFH.................. 4-5 35 Gulf Range Complex;
Oceanographic Technology Research. sources on unmanned underwater vehicles. Jacksonville Range
Science and Complex; Northeast
Technology. Range Complexes;
Virginia Capes
Range Complex.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: The Gulf Range Complex includes geographically separated areas throughout the Gulf of America.
* Only a small subset of these activities include explosive ordnance.

[[Page 19890]]

Vessel Movement
Vessels used as part of the proposed activities include both
surface and sub-surface operations of both manned and unmanned vessels
(USVs, UUVs). Navy vessels include ships, submarines, and boats ranging
in size from small, 22 ft (7 m) rigid hull inflatable boats to aircraft
carriers with lengths up to 1,092 ft (333 m). Unmanned systems may
include vehicles ranging from 4-16 ft (1.2-4.9 m) but typical size of
USVs is 36-328 ft (11-100 m), while UUVs are 33-98 ft (10-30 m) in
length. The Marine Corps operates small boats from 10-50 ft (3-15.2 m)
in length and include small unit riverine craft, rigid hull inflatable
boats and amphibious combat vehicles. Coast Guard vessels range in size
from small boats between 13 and 65 ft (3.9 to 19.8 m) to large cutters
with lengths up to 418 ft (127.4 m).
Large ships greater than 65 ft (19.8 m) generally operate at speeds
in the range of 10 to 15 knots (kn; 18.5 to 27.8 km per hour (km/hr))
for fuel conservation. Submarines generally operate at lower speeds in
transit and even lower speeds for certain tactical maneuvers. Small
craft (considered in this proposed rule to be less than 60 ft (18 m) in
length) have much more variable speeds (dependent on the mission).
While these speeds are representative of most events, some vessels need
to temporarily operate outside of these parameters. For example, to
produce the required relative wind speed over the flight deck, an
aircraft carrier vessel group engaged in flight operations must adjust
its speed through the water accordingly. Conversely, there are other
instances such as launch and recovery of a small rigid hull inflatable
boat, vessel boarding, search and seizure training events, or retrieval
of a target when vessels will be stopped or moving slowly ahead to
maintain steerage. Additionally, there are specific events including
high speed tests of newly constructed vessels. High speed ferries may
also be used to support Navy testing in Narragansett Bay.
The number of vessels used in the Study Area varies based on
military readiness requirements, deployment schedules, annual budgets,
and other unpredictable factors. Most military readiness activities
involve the use of vessels. These activities could be widely dispersed
throughout the Study Area, but would typically be conducted near naval
ports, piers, and range areas. Activities involving vessel movements
occur intermittently and are variable in duration, ranging from a few
hours to multiple weeks.
Action Proponent vessel traffic would be concentrated near Naval
Station Norfolk in Norfolk, Virginia and Naval Station Mayport in
Jacksonville, Florida. There is no seasonal differentiation in vessel
use. Large vessel movement primarily occurs with the majority of the
traffic flowing between the installations and the OPAREAs and/or
testing and training ranges. Support craft would be more concentrated
in the coastal waters in the areas of naval installations, ports, and
ranges.
The number of testing activities that include the use of vessels is
around 12 percent lower than the number of training activities, but
testing activities are more likely to include the use of larger
unmanned vessels. In addition, testing often occurs jointly with a
training event so it is likely that the testing activity would be
conducted from a vessel that was also conducting a training activity.
Vessel movement in conjunction with testing activities could occur
throughout the Study Area, but would typically be conducted near naval
ports, piers, and within range complexes.
Additionally, a variety of smaller craft will be operated within
the Study Area. Small craft types, sizes, and speeds vary. During
military readiness activities, speeds generally range from 10 to 14 kn
(18.5 to 25.9 km/hr); however, vessels can and will, on occasion,
operate within the entire spectrum of their specific operational
capabilities. In all cases, the vessels/craft will be operated in a
safe manner consistent with the local conditions.
Foreign Navies
Foreign militaries may participate in U.S. Navy training or testing
activities in the AFTT Study Area. The Navy does not consider these
foreign military activities as part of the ``specified activity'' under
the MMPA, and NMFS defers to the applicant to describe the scope of its
request for an authorization.
The participation of foreign navies varies from year to year but
overall is infrequent compared with Navy's total training and testing
activities. When foreign militaries are participating in a U.S. Navy-
led exercise or event, foreign military use of sonar and explosives,
when combined with the U.S. Navy's use of sonar and explosives, would
not result in exceedance of the analyzed levels (within each Navy
Acoustic Effects Model (NAEMO) modeled sonar and explosive bin) used
for estimating predicted impacts, which formed the basis of our
acoustic impacts effects analysis that was used to estimate take in
this proposed rule. Please see the Proposed Mitigation Measures section
and Proposed Reporting section of this proposed rule for information
about mitigation and reporting related to foreign navy activities in
the AFTT Study Area.
Standard Operating Procedures
For training and testing to be effective, Action Proponent
personnel must be able to safely use their sensors, platforms, weapons,
and other devices to their optimum capabilities and as intended for use
in missions and combat operations. The Action Proponents have developed
standard operating procedures through decades of experience to provide
for safety and mission success. Because they are essential to safety
and mission success, standard operating procedures are part of the
Proposed Action and are considered in the environmental analysis for
applicable resources (see chapter 3 (Affected Environment and
Environmental Consequences) of the 2024 AFTT Draft Supplemental EIS/
OEIS). Standard operating procedures recognized as providing a benefit
to public safety or environmental resources are described in appendix A
(Activity Descriptions) of the 2024 AFTT Draft Supplemental EIS/OEIS.
While standard operating procedures are designed for the safety of
personnel and equipment and to ensure the success of training and
testing activities, their implementation often yields additional
benefits on environmental, socioeconomic, public health and safety, and
cultural resources.
Because standard operating procedures are essential to safety and
mission success, the Action Proponents consider them to be part of the
proposed activities and have included them in the environmental
analysis. Standard operating procedures that are recognized as
providing a potential secondary benefit on marine mammals during
training and testing activities are noted below.
(i) Vessel safety;
(ii) Weapons firing safety;
(iii) Target deployment safety;
(iv) Towed in-water device safety;
(v) Pile driving safety; and
(vi) Coastal zones.
Standard operating procedures (which are implemented regardless of
their secondary benefits) are different from mitigation measures (which
are designed entirely for the purpose of avoiding or reducing impacts).
Information on mitigation measures is provided in the Proposed
Mitigation Measures section below. Additional information on standard
operating procedures is discussed in more detail in appendix A
(Activity Descriptions) of

[[Page 19891]]

the 2024 AFTT Draft Supplemental EIS/OEIS.

Description of Stressors

The Action Proponents use a variety of sensors, platforms, weapons,
and other devices, and military readiness activities using these
systems may introduce sound and energy into the environment. The
proposed military readiness activities were evaluated to identify
specific components that would act as stressors by having direct or
indirect impacts on marine mammals and their habitat. This analysis
included identification of the spatial variation of the identified
stressors. The following subsections describe the acoustic and
explosive stressors for marine mammals and their habitat within the
AFTT Study Area. Each description contains a list of activities that
may generate the stressor. Stressor/resource interactions that were
determined to have negligible (as defined for the purposes of the NEPA
analyses) or impacts that do not rise to the level of take under the
MMPA (i.e., vessel, aircraft, or weapons noise) were not carried
forward for analysis in the application. NMFS reviewed the Action
Proponents' analysis and conclusions on de minimis sources (i.e., those
that are not likely to result in the take of marine mammals) and finds
them complete and supportable (see section 3.7.4 of the technical
report ``Quantifying Acoustic Impacts on Marine Mammals and Sea
Turtles: Methods and Analytical Approach for Phase IV Training and
Testing'' (U.S. Department of the Navy, 2024)).
Acoustic Stressors
Acoustic stressors include acoustic signals emitted into the water
for a specific purpose, such as sonar, other transducers (devices that
convert energy from one form to another--in this case, into sound
waves), and air guns, as well as incidental sources of broadband sound
produced as a byproduct of vessel movement, aircraft transits, use of
weapons or other deployed objects, vibratory pile extraction, and
vibratory and impact pile driving. Explosives also produce broadband
sound but are characterized separately from other acoustic sources due
to their unique hazardous characteristics. Characteristics of each of
these sound sources are described in the following sections.
To better organize and facilitate the analysis of approximately 300
sources of underwater sound used for training and testing by the Action
Proponents, including sonars and other transducers, air guns, and
explosives, a series of source classifications, or source bins, were
used. The acoustic source classification bins do not include the
broadband noise produced incidental to pile driving, vessel and
aircraft transits, and weapons firing. Noise produced from vessel,
aircraft, and weapons firing activities are not carried forward because
those activities were found to have de minimis or no acoustic impacts,
as stated above. Of note, the source bins used in this analysis have
been revised from previous (Phase III) acoustic modeling to more
efficiently group similar sources and use the parameters of the bin for
propagation, making a comparison to previous bins impossible in most
cases as some sources are modeled at different propagation parameters.
For example, in previous analyses, non-impulsive narrowband sound
sources were grouped into bins that were defined by their acoustic
properties (i.e., frequency, source level, beam pattern, duty cycle)
or, in some cases, their purpose or application. In the current
analysis, these sources are binned based only on their acoustic
properties and not on their purpose or application. As such, sources
that previously fell into a single ``purpose-based'' bin now, in many
cases, fall into multiple bins while sources with similar acoustic
parameters that were previously sorted into separate bins due to
different purposes now share a bin. Therefore, the acoustic source bins
used in the current analysis do not represent a one-for-one replacement
with previous bins, making direct comparison not possible in most
cases.
The use of source classification bins provides the following
benefits:
(i) Allows new sensors or munitions to be used under existing
authorizations as long as those sources fall within the parameters of a
``bin'';
(ii) Improves efficiency of source utilization data collection and
reporting requirements anticipated under the MMPA authorizations;
(iii) Ensures that impacts are not underestimated, as all sources
within a given class are modeled as the most impactful source (highest
source level, longest duty cycle, or largest net explosive weight)
within that bin;
(iv) Allows analyses to be conducted in a more efficient manner,
without any compromise of analytical results; and
(v) Provides a framework to support the reallocation of source
usage (hours/explosives) between different source bins, as long as the
total numbers of takes remain within the overall analyzed and
authorized limits. This flexibility is required to support evolving
training and testing requirements, which are linked to real world
events.
Sonar and Other Transducers--
Active sonar and other transducers emit non-impulsive sound waves
into the water to detect objects, navigate safely, and communicate.
Passive sonars differ from active sound sources in that they do not
emit acoustic signals; rather, they only receive acoustic information
about the environment, or listen. In this proposed rule, the terms
sonar and other transducers will be used to indicate active sound
sources unless otherwise specified.
The Action Proponents employ a variety of sonars and other
transducers to obtain and transmit information about the undersea
environment. Some examples are mid-frequency hull-mounted sonars used
to find and track enemy submarines; high-frequency small object
detection sonars used to detect mines; high-frequency underwater modems
used to transfer data over short ranges; and extremely high-frequency
(greater than 200 kilohertz (kHz)) Doppler sonars used for navigation,
like those used on commercial and private vessels. The characteristics
of these sonars and other transducers, such as source level (SL), beam
width, directivity, and frequency, depend on the purpose of the source.
Higher frequencies can carry more information or provide more
information about objects off which they reflect, but attenuate more
rapidly. Lower frequencies attenuate less rapidly, so they may detect
objects over a longer distance, but with less detail.
Propagation of sound produced underwater is highly dependent on
environmental characteristics such as bathymetry, seafloor type, water
depth, temperature, and salinity. The sound received at a particular
location will be different than near the source due to the interaction
of many factors, including propagation loss; how the sound is
reflected, refracted, or scattered; the potential for reverberation;
and interference due to multi-path propagation. In addition, absorption
greatly affects the distance over which higher-frequency sounds
propagate. The effects of these factors are explained in appendix D
(Acoustic and Explosive Impacts Supporting Information) of the 2024
AFTT Draft Supplemental EIS/OEIS. Because of the complexity of
analyzing sound propagation in the ocean environment, the Action
Proponents rely on acoustic models in their environmental analyses that
consider sound source characteristics and varying ocean conditions
across the AFTT Study Area. For additional information on how
propagation is accounted for, see the technical report

[[Page 19892]]

``Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles:
Methods and Analytical Approach for Phase IV Training and Testing''
(U.S. Navy, 2024).
The sound sources and platforms typically used in military
readiness activities analyzed in the application are described in
appendix A (Activity Descriptions) of the 2024 AFTT Draft Supplemental
EIS/OEIS. Sonars and other transducers used to obtain and transmit
information underwater during military readiness activities generally
fall into several categories of use described below.
Anti-Submarine Warfare
Sonar used during anti-submarine warfare training and testing would
impart the greatest amount of acoustic energy of any category of sonar
and other transducers analyzed in this proposed rule. Types of sonars
used to detect potential enemy vessels include hull-mounted, towed,
line array, sonobuoy, helicopter dipping, and torpedo sonars. In
addition, acoustic targets and decoys (countermeasures) may be deployed
to emulate the sound signatures of vessels or repeat received signals.
Most anti-submarine warfare sonars are mid-frequency (1-10 kHz)
because mid-frequency sound balances sufficient resolution to identify
targets with distance over which threats can be identified. However,
some sources may use higher or lower frequencies. Duty cycles can vary
widely, from rarely used to continuously active. Anti-submarine warfare
sonars can be wide-ranging in a search mode or highly directional in a
track mode.
Most anti-submarine warfare activities involving submarines or
submarine targets would occur in waters greater than 600 ft (182.9 m)
deep due to safety concerns about running aground at shallower depths.
Sonars used for anti-submarine warfare activities would typically be
used beyond 12 nmi (22.2 km) from shore. Exceptions include use of
dipping sonar by helicopters, pierside testing and maintenance of
systems while in port, and system checks while transiting to or from
port.
Mine Warfare, Object Detection, and Imaging
Sonars used to locate mines and other small objects, as well as
those used in imaging (e.g., for hull inspections or imaging of the
seafloor), are typically high-frequency or very high-frequency. Higher
frequencies allow for greater resolution and, due to their greater
attenuation, are most effective over shorter distances. Mine detection
sonar can be deployed (towed or vessel hull-mounted) at variable depths
on moving platforms (ships, helicopters, or unmanned vehicles) to sweep
a suspected mined area. Hull-mounted anti-submarine sonars can also be
used in an object detection mode known as ``Kingfisher'' mode. Sonars
used for imaging are usually used in close proximity to the area of
interest, such as pointing downward near the seafloor.
Mine detection sonar use would be concentrated in areas where
practice mines are deployed, typically in water depths less than 200 ft
(60.9 m), and at established training or testing minefields or
temporary minefields close to strategic ports and harbors. Kingfisher
mode on vessels is most likely to be used when transiting to and from
port. Sound sources used for imaging would be used throughout the AFTT
Study Area.
Navigation and Safety
Similar to commercial and private vessels, the Action Proponents'
vessels employ navigational acoustic devices, including speed logs,
Doppler sonars for ship positioning, and fathometers. These may be in
use at any time for safe vessel operation. These sources are typically
highly directional to obtain specific navigational data.
Communication
Sound sources used to transmit data (such as underwater modems),
provide location (pingers), or send a single brief release signal to
seafloor-mounted devices (acoustic release) may be used throughout the
AFTT Study Area. These sources typically have low duty cycles and are
usually only used when it is necessary to send a detectable acoustic
message.
Classification of Sonar and Other Transducers
Sonars and other transducers are grouped into bins based on their
acoustic properties. Sonars and other transducers are now grouped into
bins based on the frequency or bandwidth, source level, duty-cycle, and
three-dimensional beam coverage. Unless stated otherwise, a reference
distance of decibel (dB) microPascal ([mu]Pa) at 1 m (3.3 ft) is used
for sonar and other transducers.
(i) Frequency of the non-impulsive acoustic source:
a. Low-frequency sources operate below 1 kHz;
b. Mid-frequency sources operate at or above 1 kHz, up to and
including 10 kHz;
c. High-frequency sources operate above 10 kHz, up to and including
100 kHz; and
d. Very high-frequency sources operate above 100 kHz but below 200
kHz.
(ii) Sound pressure level (SPL):
a. Greater than 160 dB referenced to 1 microPascal (re 1 [mu]Pa),
but less than 185 dB re 1 [mu]Pa;
b. Equal to 185 dB re 1 [mu]Pa and up to 205 dB re 1 [mu]Pa; and
c. Greater than 205 dB re 1 [mu]Pa.
Active sonar and other transducer use that was quantitatively
analyzed in the Study Area are shown in table 10.

Table 10--Sonar and Other Transducers Quantitatively Analyzed in the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Navy Coast Guard Coast Guard
Source type Source category Description Unit Navy training training 7- training training 7- Navy testing Navy testing
annual year total annual year total annual 7-year total
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Broadband............................ LF..................... <205 dB................. H - - - - 206-252 1,580
Broadband............................ LF to MF............... <205 dB................. H - - - - 1,501-1,503 10,519
Broadband............................ LF to HF............... <205 dB................. C - - - - 791-1,020 5,101
Broadband............................ LF to HF............... <205 dB................. H - - - - 2,367-2,571 16,356
Broadband............................ MF to HF............... <205 dB................. C 133 931 - - - -
Broadband............................ MF to HF............... <205 dB................. H 935-951 6,595 280 1,960 2,749-2,950 19,308
Broadband............................ HF to VHF.............. <205 dB................. H 10 70 - - - -
Low-frequency acoustic............... LFL.................... 160 dB to 185 dB........ H - - - - 1,969 13,783
Low-frequency acoustic............... LFM.................... 185 dB to 205 dB........ C - - - - 360 2,520
Low-frequency acoustic............... LFM.................... 185 dB to 205 dB........ H 746 5,219 - - 5,386-6,106 39,862
Low-frequency acoustic............... LFH.................... >205 dB................. C 1,920-2,020 13,760 - - 6,078-6,084 42,588

[[Page 19893]]

Low-frequency acoustic............... LFH.................... >205 dB................. H 144 1,008 - - 414-479 3,101
Mid-frequency acoustic............... MFL.................... 160 dB to 185 dB........ H - - - - 3,238-3,582 22,336
Mid-frequency acoustic............... MFM.................... 185 dB to 205 dB........ C 6,825-6,964 48,196 - - 16,017-16,040 111,849
Mid-frequency acoustic............... MFM.................... 185 dB to 205 dB........ H 2 14 - - 3,081-3,509 23,012
Mid-frequency acoustic............... MFH.................... >205 dB................. H 2,343-2,466 16,794 - - 7,203-7,943 52,542
High-frequency acoustic.............. HFL.................... 160 dB to 185 dB........ H 169 1,183 - - 96 672
High-frequency acoustic.............. HFM.................... 185 dB to 205 dB........ C - - - - 860-1,660 8,420
High-frequency acoustic.............. HFM.................... 185 dB to 205 dB........ H 1,253-1,255 8,777 210 1,470 4,125-4,489 29,941
High-frequency acoustic.............. HFH.................... >205 dB................. C 138 966 - - 1,621-1,858 11,684
High-frequency acoustic.............. HFH.................... >205 dB................. H 3,892-3,940 27,436 - - 3,779-4,580 28,383
Very high-frequency acoustic......... VHFL................... 160 dB to 185 dB........ H 12 84 - - - -
Very high-frequency acoustic......... VHFM................... 185 dB to 205 dB........ H 918 6,426 - - 120 840
Very high-frequency acoustic......... VHFH................... >205 dB................. C - - - - 69-103 520
Very high-frequency acoustic......... VHFH................... >205 dB................. H 579 4,051 140 980 5,584 -39,088
Hull-mounted surface ship sonar...... MF1C................... Hull-mounted surface H 661-722 4,811 - - 1,139 7,974
ship sonar with duty
cycle >80% (previously
MF11).
Hull-mounted surface ship sonar...... MF1K................... Hull-mounted surface H 280 1,957 - - 108 759
ship sonar in
Kingfisher mode.
Hull-mounted surface ship sonar...... MF1.................... Hull-mounted surface H 3,498-3,870 25,602 - - 1,102-1,390 8,464
ship sonar.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: < = less than, C = count, dB = decibel, H = hours; - = not applicable.

Air Guns--
Air guns are essentially stainless steel tubes charged with high-
pressure air via a compressor. An impulsive sound is generated when the
air is almost instantaneously released into the surrounding water.
Small air guns with capacities up to 60 cubic inches (in\3\) would be
used during testing activities in various offshore areas in the AFTT
Study Area.
Generated impulses would have short durations, typically a few
hundred milliseconds, with dominant frequencies below 1 kHz. The root-
mean-square (RMS) SPL and peak pressure (SPL peak) at a distance 1 m
(3.3 ft) from the air gun would be approximately 215 dB re 1 [mu]Pa and
227 dB re 1 [mu]Pa, respectively, if operated at the full capacity of
60 in\3\. The size of the air gun chamber can be adjusted, which would
result in lower SPLs and sound exposure level (SEL) per shot. The air
gun and non-explosive impulsive sources that were quantitatively
analyzed in the Study Area are shown in table 11.

Table 11--Testing Air Gun and Non-Explosive Impulsive Sources Quantitatively Analyzed in the AFTT Study Area
----------------------------------------------------------------------------------------------------------------
Source class category Description Unit Testing annual Testing 7-year total
----------------------------------------------------------------------------------------------------------------
NEI............................ Non-explosive C 192-240 1,488
impulsive.
AG............................. Air gun........... C 4,400-5,400 33,800
----------------------------------------------------------------------------------------------------------------
Note: C: count.

Pile Driving--
Impact and vibratory pile driving and extraction would occur during
Expeditionary Warfare, Port Damage Repair training in Gulfport, MS. The
pile driving method, pile type and size, and assumptions for acoustic
impact analysis are presented in table 12. This training activity would
occur up to four times per year. Training events are typically 5 days
each, for a total of 20 days per year. The training would involve the
installation and extraction of 27-inch (0.69 m) steel sheets,
installation of timber or plastic round 16-inch (0.41 m) piles using
impact (impulsive) and vibratory (non-impulsive) methods, and the
extraction of timber or plastic round 16-inch piles. When training
events are complete, all piles and sheets are extracted using vibratory
or dead pull methods. Crews would extract up to 12 piles in a 24-hour
period.

[[Page 19894]]

Table 12--Port Damage Repair Training Piles Quantitatively Analyzed and Associated Underwater Sound Levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
SEL (single
Number of Number of Peak SPL (dB strike; dB re 1 RMS SPL (dB
Method Pile size and type piles annual piles 7-year re 1 [mu]Pa) [mu]Pa2 re 1 [mu]Pa) Reference
total [middot]s)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact......................... 16-inch timber or 80 560 180 160 170 Caltrans (2020)--
plastic round. Ballena Isle
Marina.
Vibratory...................... 16-inch timber or 160 1,120 .............. ................ 162 Caltrans (2020)--
plastic round. Norfolk Naval
Station.
Vibratory...................... 27-inch steel 240 1,680 .............. ................ 159 Naval Facilities
sheet. Engineering
Command
Southwest
(2020).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Impact method is for installation only.

Only one hammer would be used at any given point in time; there
would not be any instances where multiple piles would be driven
simultaneously. All piles and sheets would be extracted using the
vibratory hammer. Timber or plastic piles would also be extracted using
a dead pull method.
Impact pile driving would involve the use of an impact hammer with
both it and the pile held in place by a crane. When the pile driving
starts, the hammer part of the mechanism is raised up and allowed to
fall, transferring energy to the top of the pile. The pile is thereby
driven into the sediment by a repeated series of these hammer blows.
Each blow results in an impulsive sound emanating from the length of
the pile into the water column as well as from the bottom of the pile
through the sediment. Broadband impulsive signals are produced by
impact pile driving methods, with most of the acoustic energy
concentrated below 1,000 hertz (Hz) (Hildebrand, 2009). For the
purposes of this analysis, the Action Proponents assume the impact pile
driver would generally operate on average 60 strikes per pile.
Vibratory installation and extraction would involve the use of a
vibratory hammer suspended from the crane and attached to the top of a
pile. The pile is then vibrated by hydraulic motors rotating eccentric
weights in the mechanism, causing a rapid up and down vibration in the
pile, driving the pile into the sediment. During extraction, the
vibration causes the sediment particles in contact with the pile to
lose frictional grip on the pile. The crane slowly lifts the vibratory
driver and pile until the pile is free of the sediment. In some cases,
the crane may be able to lift the pile and vibratory driver without
vibrations from the driver (dead pull), in which case no noise would be
introduced into the water. Vibratory driving and extraction create
broadband, continuous, non-impulsive noise at low source levels, for a
short duration with most of the energy dominated by lower frequencies.
Port Damage Repair training would occur in shallow water, and sound
would be transmitted on direct paths through the water, be reflected at
the water surface or bottom, or travel through seafloor substrate. Soft
substrates such as sand would absorb or attenuate the sound more
readily than hard substrates (rock), which may reflect the acoustic
wave. The predicted sound levels produced by pile driving by method,
pile size, and type for Port Damage Repair training are presented in
table 12.
In addition to underwater noise, the installation and extraction of
piles also results in airborne noise in the environment, denoted dBA.
dBA is an A-weighted decibel level that represents the relative
loudness of sounds as perceived by the human ear. A-weighting gives
more value to frequencies in the middle of human hearing and less value
to frequencies at the edges as compared to a flat or unweighted decibel
level. Impact pile driving creates in-air impulsive sound about 100 dBA
re 20 [mu]Pa at a range of 15 m for 24-inch (0.61 m) steel piles
(Illingworth and Rodkin, 2016). During vibratory extraction, the three
aspects that generate airborne noise are the crane, the power plant,
and the vibratory extractor. The average sound level recorded in air
during vibratory extraction was about 85 dBA re 20 [mu]Pa (94 dB re 20
[mu]Pa) within a range of 32.8-49.2 ft (10-15 m) (Illingworth and
Rodkin, 2015).
Explosive Stressors
This section describes the characteristics of explosions during
military readiness activities. The activities analyzed in the
application that use explosives are described in appendix A (Activity
Descriptions) of the 2024 AFTT Draft Supplemental EIS/OEIS, and
terminology and metrics used when describing explosives in the
application are in appendix D (Acoustic and Explosive Impacts
Supporting Information) of the 2024 AFTT Draft Supplemental EIS/OEIS.
The near-instantaneous rise from ambient to an extremely high peak
pressure is what makes an explosive shock wave potentially damaging.
Farther from an explosive, the peak pressures decay and the explosive
waves propagate as an impulsive, broadband sound. Several parameters
influence the effect of an explosive: the weight of the explosive
warhead, the type of explosive material, the boundaries and
characteristics of the propagation medium, and the detonation depth in
water. The net explosive weight (NEW), the explosive power of a charge
expressed as the equivalent weight of trinitrotoluene (commonly
referred to as TNT), accounts for the first two parameters.
Explosions in Water--
Explosive detonations during military readiness activities are
associated with high-explosive munitions, including, but not limited to
bombs, missiles, rockets, naval gun shells, torpedoes, mines,
demolition charges, and explosive sonobuoys. Explosive detonations
during military readiness activities involving the use of high-
explosive munitions, including bombs, missiles, and naval gun shells,
would occur in the air or near the water's surface. Explosive
detonations associated with torpedoes and explosive sonobuoys would
occur in the water column; mines and demolition charges would be
detonated in the water column or on the ocean floor. The Coast Guard
usage of explosives is limited to medium- and large-caliber munitions
used during gunnery exercises. Most detonations would occur in waters
greater than 200 ft (60.9 m) in depth and greater than 3 nmi (5.6 km)
from shore, although mine warfare, demolition, and some testing
detonations would occur in shallow water close to shore.
To better organize and facilitate the analysis of explosives used
by the Action Proponents during military readiness activities that
would detonate in water or at the water surface, explosive
classification bins were

[[Page 19895]]

developed. The use of explosive classification bins provides the same
benefits as described for acoustic source classification bins in the
Sonar and Other Transducers section. Explosives detonated in water are
binned by NEW. Table 13 shows explosives use that was quantitatively
analyzed in the Study Area. A range of annual use indicates that
occurrence is anticipated to vary annually, consistent with the
variation in the number of annual activities described in chapter 2
(Description of Proposed Action and Alternatives) of the 2024 AFTT
Draft Supplemental EIS/OEIS. The 7-year total takes that variability
into account.

Table 13--Explosive Sources Quantitatively Analyzed Proposed for Use Underwater or at the Water Surface
--------------------------------------------------------------------------------------------------------------------------------------------------------
Coast Guard Coast Guard
Bin Net explosive Example explosive Navy training Navy training training training 7- Navy testing Navy testing
weight source annual 7-year annual year annual 7-year
--------------------------------------------------------------------------------------------------------------------------------------------------------
E1............... 0.1-0.25 Medium-caliber 3,002 21,014 - - 1,825 12,775
projectile.
E2............... >0.25-0.5 LAW rocket......... 60 420 - - - -
E3............... >0.5-2.5 2.75-inch rocket... 5,078 35,546 180 1,260 1,069-1,971 8,705
E4............... >2.5-5 Mine neutralization 82 574 - - 2,893-4,687 30,889
charge.
E5............... >5-10 Large-caliber 1,109 7,763 - - 1,268-1,860 11,540
projectile.
E6............... >10-20 Hellfire missile... 508 3,556 - - 17-25 125
E7............... >20-60 Demo block/shaped 10 70 - - 8-22 62
charge.
E8............... >60-100 Maverick missile... 20 140 - - 10-13 41
E9............... >100-250 500 lb bomb........ 138 966 - - 5 35
E10.............. >250-500 Harpoon missile.... 71 497 - - 4 28
E11.............. >500-675 Torpedo............ 1 7 - - 1-2 8
E12.............. >675-1,000 2,000 lb bomb...... 20 140 - - - -
E16.............. >7,250-14,500 Small ship shock - - - - 0-6 15
trial.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: > = greater than, lb = pound, - = not applicable.

Propagation of explosive pressure waves in water is highly
dependent on environmental characteristics such as bathymetry, seafloor
type, water depth, temperature, and salinity, which affect how the
pressure waves are reflected, refracted, or scattered; the potential
for reverberation; and interference due to multi-path propagation. In
addition, absorption greatly affects the distance over which higher-
frequency components of explosive broadband noise can propagate.
Appendix D (Acoustic and Explosive Impacts Supporting Information) of
the 2024 AFTT Draft Supplemental EIS/OEIS explains the characteristics
of explosive detonations and how the above factors affect the
propagation of explosive energy in the water. Because of the complexity
of analyzing sound propagation in the ocean environment, the Action
Proponents rely on acoustic models in their environmental analyses that
consider sound source characteristics and varying ocean conditions
across the Study Area.
Vessel Strike
NMFS also considered the likelihood that vessel movement during
military readiness activities could result in an incidental, but
intentional, strike of a marine mammal in the AFTT Study Area, which
has the potential to result in serious injury or mortality. Vessel
strikes are not specific to any specific military readiness activity
but rather, a limited, sporadic, and incidental result of the Action
Proponents' vessel movement during military readiness activities within
the Study Area. Vessel strikes from commercial, recreational, and
military vessels are known to seriously injure and occasionally kill
cetaceans (Abramson et al., 2011; Berman-Kowalewski et al., 2010;
Calambokidis, 2012, Crum et al., 2019, Douglas et al., 2008, Laggner,
2009, Lammers et al., 2003, Van der Hoop et al., 2012, Van der Hoop et
al., 2013), although reviews of the literature on vessel strikes mainly
involve collisions between commercial vessels and whales (Jensen and
Silber, 2003, Laist et al., 2001). Vessel speed, size, and mass are all
important factors in determining both the potential likelihood and
impacts of a vessel strike to marine mammals (Blondin et al., 2025;
Conn and Silber, 2013; Garrison et al., 2025; Gende et al., 2011;
Redfern et al., 2019; Silber et al., 2010; Szesciorka et al., 2019;
Vanderlaan and Taggart, 2007; Wiley et al., 2016). For large vessels,
speed and angle of approach can influence the severity of a strike.
The Action Proponents' vessels transit at speeds that are optimal
for fuel conservation or to meet training and testing requirements.
From unpublished Navy data, average median speed for large Navy ships
in the other Navy ranges from 2011-2015 varied from 10 to 15 kn (18.5
to 27.8 km/hr) depending on ship class and geographic location (i.e.,
slower speeds close to the coast). Similar patterns are anticipated in
the AFTT Study Area. A full description of the Action Proponents'
vessels proposed for use during military readiness activities can be
found in chapter 2 (Description of Proposed Action and Alternatives) of
the 2024 AFTT Draft Supplemental EIS/OEIS.
While these speeds for large Navy vessels are representative of
most events, some of the Action Proponents' vessels may need to
temporarily operate outside of these parameters. For example, to
produce the required relative wind speed over the flight deck, an
aircraft carrier engaged in flight operations must adjust its speed
through the water accordingly. There are a few specific events,
including high speed tests of newly constructed vessels, where the
Action Proponents' vessel would operate at higher speeds. High speed
ferries may also be used to support Navy testing in Narragansett Bay.
By comparison, there are other instances when the Action Proponents
vessel would be stopped or moving slowly ahead to maintain steerage,
such as launch and recovery of a small rigid hull inflatable boat;
vessel boarding, search, and seizure training events; or retrieval of a
target.
Large Navy vessels (greater than 65 ft (19.8 m)) and Coast Guard
vessels within the offshore areas of range complexes and testing ranges
operate differently from commercial vessels, which may reduce potential
vessel strikes of large whales. Surface ships operated by or for the
Navy have multiple personnel assigned to stand watch at all times, when
a ship or surfaced submarine is moving through the water (underway). A
primary duty of personnel standing watch on surface ships is to detect
and report all objects and disturbances sighted in the water that may
indicate a threat to the vessel

[[Page 19896]]

and its crew, such as debris, a periscope, surfaced submarine, or
surface disturbance. Per vessel safety requirements, personnel standing
watch also report any marine mammals sighted in the path of the vessel
as a standard collision avoidance procedure. All vessels proceed at a
safe speed so they can take proper and effective action to avoid a
collision with any sighted object or disturbance and can stop within a
distance appropriate to the prevailing circumstances and conditions. As
described in the Standard Operating Procedures section, the Action
Proponents utilize Lookouts to avoid collisions, and Lookouts are
trained to spot marine mammals so that vessels may change course or
take other appropriate action to avoid collisions. Despite the
precautions, should a vessel strike occur, NMFS anticipates that it
would likely result in incidental take in the form of serious injury
and/or mortality, though it is possible that it could result in non-
serious injury (Level A harassment). Accordingly, for the purposes of
this analysis, NMFS assumes that any vessel strike would result in
serious injury or mortality.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation Measures section, Proposed Monitoring section, and Proposed
Reporting section).

Description of Marine Mammals in the Area of Specified Activities

Marine mammal species and their associated stocks that have the
potential to occur in the AFTT Study Area are presented in table 14
along with each stock's Endangered Species Act (ESA) and MMPA statuses,
abundance estimate and associated coefficient of variation (CV) value,
minimum abundance estimate, potential biological removal (PBR), annual
M/SI, and potential occurrence in the AFTT Study Area. The Action
Proponents request authorization to take individuals of 41 species (81
stocks) by Level A and Level B harassment incidental to military
readiness activities from the use of sonar and other transducers, in-
water detonations, air guns, pile driving/extraction, and vessel
movement in the AFTT Study Area. Of note, the 2019 AFTT Final Rule (84
FR 70712, December 23, 2019) refers to the Northern Gulf of America
stock of Bryde's whales (Balaenoptera edeni). These whales were
subsequently described as a new species, Rice's whale (Balaenoptera
ricei) (Rosel et al., 2021), and NMFS refers to them as Rice's whale
throughout this rulemaking. Currently, the North Atlantic right whale
(NARW; Eubalaena glacialis) has critical habitat designated under the
ESA in the AFTT Study Area, and the Rice's whale has proposed ESA-
designated critical habitat in the AFTT Study Area (see Critical
Habitat section below).
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments), and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species). Additional information on the
general biology and ecology of marine mammals is included in the 2024
AFTT Draft Supplemental EIS/OEIS.
Table 14 incorporates the best available science, including data
from the U.S. Atlantic and Gulf of Mexico Marine Mammal Stock
Assessment Report (Hayes et al., 2024) (now referred to as the Gulf of
America; see https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments), and 2024 draft SAR, as
well as monitoring data from the Navy's marine mammal research efforts
(note, the application includes information from the 2022 final SAR but
does not include information from the 2023 final SAR and 2024 draft SAR
as they were not available at the time of application submission).

[[Page 19897]]

Table 14--Marine Mammal Occurrence in the AFTT Study Area \1\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Stock abundance
ESA/ MMPA (CV, Nmin, most Occurrence in Occurrence in port
Common name Scientific name Stock status; recent abundance PBR Annual M/ Occurrence in associated and pierside
strategic (Y/ survey) \3\ SI \4\ range complexes inshore waters locations
N) \2\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Order Artiodactyla--Cetacea--Mysticeti (baleen whales)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae:
North Atlantic Right Whale Eubalaena glacialis Western............ E, D, Y 372 (0, 367, 2023) 0.73 14.8 Northeast RC, NUWC Northeast RC Civilian Ports:
\5\. Division Newport Inshore, Boston, MA,
Testing Range, Jacksonville RC Earle, NJ,
VACAPES RC, Navy Inshore. Delaware Bay, DE,
Cherry Point RC, Hampton Roads,
JAX RC, SFOMF, VA, Morehead
Key West RC City, NC,
(extralimital), Wilmington, NC,
NSWC Panama City Kings Bay, GA,
Division Testing Savannah, GA,
Range Mayport, FL, Port
(extralimital), Canaveral, FL
Gulf RC (extralimital);
(extralimital), Coast Guard
SINKEX Box, Other Stations: Boston,
AFTT Areas. MA, Virginia
Beach, VA,
Charleston, SC,
Mayport, FL, Cape
Canaveral, FL
(extralimital).
Family Balaenopteridae
(rorquals):
Blue Whale.................. Balaenoptera Western North E, D, Y UNK (UNK, 402, See 0.8 0 Northeast RC, NUWC N/A............... N/A.
musculus. Atlantic. SAR) \6\. Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SINKEX
Box, Other AFTT
Areas.
Bryde's Whale............... Balaenoptera edeni. Primary............ (7 8) .................. ......... ......... Other AFTT Areas.. N/A............... N/A.
Fin Whale................... Balaenoptera Western North E, D, Y 6,802 (0.24, 11 2.05 Northeast RC,
physalus. Atlantic. 5,573, 2021). VACAPES RC, Navy
Cherry Point RC,
JAX RC, Key West
RC, Gulf RC
(extralimital),
NSWC Panama City
Testing Range
(extralimital),
SINKEX Box, Other
AFTT Areas.
Fin Whale................... Balaenoptera Gulf of St. .............. .................. ......... ......... Other AFTT Areas..
physalus. Lawrence.
Fin Whale................... Balaenoptera West Greenland..... .............. .................. ......... ......... Other AFTT Areas..
physalus.
Humpback Whale.............. Megaptera Gulf of Maine...... -, -, N 1,396 (0, 1380, 22 12.15 Northeast RC, NUWC Northeast RC Civilian Ports:
novaeangliae. 2016). Division, Newport Inshore, VACAPES Boston, MA,
Testing Range, Inshore, Earle, NJ,
VACAPES RC, Navy Jacksonville RC Delaware Bay, DE,
Cherry Point RC, Inshore. Hampton Roads,
JAX RC, SFOMF, VA, Morehead
Key West RC, NSWC City, NC,
Panama City Wilmington, NC;
Division Testing Coast Guard
Range, Gulf RC, Stations: Boston,
SINKEX Box, Other MA, Newport, RI,
AFTT Areas. Virginia Beach,
VA, Charleston,
SC, Mayport, FL,
Cape Canaveral,
FL, Fort Pierce,
FL, Dania, FL,
Miami, FL, Key
West, FL, St.
Petersburg, FL,
Pensacola, FL,
New Orleans, LA,
Corpus Christi,
TX.

[[Page 19898]]

Minke Whale................. Balaenoptera Canadian East Coast -, -, N 21,968 (0.31, 170 9.4 Northeast RC, NUWC Northeast RC Civilian Ports:
acutorostrata. 17,002, 2021). Division Newport Inshore, VACAPES Boston, MA,
Testing Range, Inshore, Earle, NJ,
VACAPES RC, Navy Jacksonville RC Delaware Bay, DE,
Cherry Point RC, Inshore. Hampton Roads,
JAX RC, SFOMF, VA, Morehead
Key West RC, NSWC City, NC,
Panama City Wilmington, NC,
Division Testing Kings Bay, GA,
Range, Gulf RC, Savannah, GA;
SINKEX Box, Other Coast Guard
AFTT Areas. Stations: Boston,
MA, Newport, RI,
Virginia Beach,
VA, Charleston,
SC, Mayport, FL,
Cape Canaveral,
FL, Fort Pierce,
FL, Dania, FL,
Miami, FL, Key
West, FL, St.
Petersburg, FL,
Pensacola, FL,
New Orleans, LA,
Corpus Christi,
TX.
Minke Whale................. Balaenoptera West Greenland..... (\9\) .................. ......... ......... Other AFTT Areas..
acutorostrata.
Rice's Whale................ Balaenoptera ricei. Northern Gulf of E, -, Y 51 (0.5, 34, 2018) 0.1 \10\ 0.5 Gulf RC, Key West Gulf RC Inshore... Civilian Ports:
America. RC, NSWC Panama Tampa, FL,
City Testing Beaumont, TX,
Range. Corpus Christi,
TX.
Sei Whale................... Balaenoptera Nova Scotia........ E, D, Y 6,292 (1.02, 6.2 0.6 Northeast RC, NUWC N/A............... N/A.
borealis. 3,098, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, Gulf RC,
SINKEX Box, Other
AFTT Areas.
Sei Whale................... Balaenoptera Labrador Sea....... (\11\) .................. ......... ......... Other AFTT Areas..
borealis.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Odontoceti (toothed whales, dolphins, and porpoises)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
Sperm Whale................. Physeter North Atlantic..... E, D, Y 5,895 (0.29, 9.28 0.2 Northeast RC, NUWC N/A............... N/A.
macrocephalus. 4,639, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, Gulf RC,
SINKEX Box, Other
AFTT Areas.
Sperm Whale................. Physeter Northern Gulf of E, D, Y 1,180 (0.22, 983, 2 9.6 Gulf, NSWC Panama N/A............... N/A.
macrocephalus. America. 2018). City Testing
Range.
Sperm Whale................. Physeter Puerto Rico and E, D, Y UNK (UNK, UNK, See UNK UNK Other AFTT Areas.. N/A............... N/A.
macrocephalus. U.S. Virgin SAR).
Islands.
Family Kogiidae:
Dwarf Sperm Whale........... Kogia sima......... Northern Gulf of -, -, N 336 (0.35, 253, 2.5 31 Gulf RC........... N/A............... N/A.
America \12\. 2018).
Dwarf Sperm Whale........... Kogia sima......... Western North -, -, N 9,474 (0.36, 57 UNK Northeast RC, NUWC N/A............... N/A.
Atlantic \13\. 7,080, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Pygmy Sperm Whale........... Kogia breviceps.... Northern Gulf of -, -, N 336 (0.35, 253, 2.5 31 Gulf RC........... N/A............... N/A.
America \12\. 2018).

[[Page 19899]]

Pygmy Sperm Whale........... Kogia breviceps.... Western North -, -, N 9,474 (0.36, 57 UNK Northeast RC, NUWC N/A............... N/A.
Atlantic \13\. 7,080, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Family Ziphiidae (beaked
whales):
Blainville's Beaked Whale... Mesoplodon Northern Gulf of -, -, N 98 (0.46, 68, 0.7 5.2 Gulf RC........... N/A............... N/A.
densirostris. America. 2018).
Blainville's Beaked Whale... Mesoplodon Western North -, -, N 2,936 (0.26, 24 0 Northeast RC, NUWC N/A............... N/A.
densirostris. Atlantic \14\. 2,374, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, Gulf RC,
Other AFTT Areas.
Goose-Beaked Whale.......... Ziphius cavirostris Northern Gulf of -, -, N 18 (0.75, 10, 0.1 5.2 Gulf RC........... N/A............... N/A.
America. 2018).
Goose-Beaked Whale.......... Ziphius cavirostris Puerto Rico and -, -, Y UNK (UNK, UNK, N/ UNK UNK Other AFTT Areas.. N/A............... N/A.
U.S. Virgin A).
Islands.
Goose-Beaked Whale.......... Ziphius cavirostris Western North -, -, N 4,260 (0.24, 38 0.2 Northeast RC, NUWC N/A............... N/A.
Atlantic. 3,817, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Other AFTT Areas.
Gervais' Beaked Whale....... Mesoplodon Northern Gulf of -, -, N 20 (0.98, 10, 0.1 5.2 Gulf RC........... N/A............... N/A.
europaeus. America. 2018).
Gervais' Beaked Whale....... Mesoplodon Western North -, -, N 8,595 (0.24, 70 0 Northeast RC, NUWC N/A............... N/A.
europaeus. Atlantic \15\. 7,022, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, Gulf RC,
Other AFTT Areas.
Northern Bottlenose Whale... Hyperoodon Western North -, -, N UNK (UNK, UNK, UNK 0 Other AFTT Areas.. N/A............... N/A.
ampullatus. Atlantic. 2016).
Sowerby's Beaked Whale...... Mesoplodon bidens.. Western North -, -, N 492 (0.50, 340, 3.4 0 Northeast RC, NUWC N/A............... N/A.
Atlantic. 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, Gulf RC,
Other AFTT Areas.
True's Beaked Whale......... Mesoplodon mirus... Western North -, -, N 4,480 (0.34, 34 0.2 Northeast RC, NUWC N/A............... N/A.
Atlantic. 3,391, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, Gulf RC,
Other AFTT Areas.
Family Delphinidae:
Atlantic Spotted Dolphin.... Stenella frontalis. Northern Gulf of -, -, N 21,506 (0.26, 166 36 Gulf RC, Other N/A............... N/A.
America. 17,339, 2018). AFTT Areas.
Atlantic Spotted Dolphin.... Stenella frontalis. Puerto Rico and -, -, Y UNK (UNK, UNK, N/ UNK UNK Other AFTT Areas.. N/A............... N/A.
U.S. Virgin A).
Islands.
Atlantic Spotted Dolphin.... Stenella frontalis. Western North -, -, N 31,506 (0.28, 250 0 Northeast RC, NUWC N/A............... N/A.
Atlantic. 25,042, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Atlantic White-Sided Dolphin Lagenorhynchus Western North -, -, N 93,233 (0.71, 544 28 Northeast RC, N/A............... Civilian Ports:
acutus. Atlantic. 54,443, 2021). VACAPES RC, Other Boston, MA; Coast
AFTT Areas. Guard Stations:
Boston, MA.
Bottlenose Dolphin.......... Tursiops truncatus. Biscayne Bay....... -, -, N 241 (0.04, 233, 2.3 1 Other AFTT Areas.. N/A............... N/A.
2019).

[[Page 19900]]

Tamanend's bottlenose Tursiops erebennus. Western North -, -, Y 2,541 (0.46, 18 0.2 JAX RC............ JAX RC Inshore.... Civilian Ports:
dolphin. Atlantic, Central 1,760, 2021). Port Canaveral,
Florida Coastal. FL.
Bottlenose Dolphin.......... Tursiops truncatus. Central GA -, -, N UNK (UNK, UNK, UND 0.4 Other AFTT Areas.. N/A............... N/A.
Estuarine. 2008-2009).
Bottlenose Dolphin.......... Tursiops truncatus. Charleston -, -, Y UNK (UNK, UNK, UND 2.2 Other AFTT Areas.. JAX RC Inshore.... N/A.
Estuarine. 2005-2006).
Bottlenose Dolphin.......... Tursiops truncatus. Gulf of America Y .................. ......... ......... Gulf RC........... Gulf RC Inshore... N/A.
Bay, Sound, and
Estuaries \16\.
Bottlenose Dolphin.......... Tursiops truncatus. Gulf of America -, -, N 16,407 (0.17, 114 9.2 Gulf RC........... Gulf RC Inshore... N/A.
Eastern Coastal. 14,199, 2018).
Bottlenose Dolphin.......... Tursiops truncatus. Gulf of America -, -, N 11,543 (0.19, 89 28 Gulf RC........... Gulf RC Inshore... N/A.
Northern Coastal. 9,881, 2018).
Bottlenose Dolphin.......... Tursiops truncatus. Northern Gulf of -, -, N 7,462 (0.31, 58 32 Gulf RC........... N/A............... N/A.
America Oceanic. 5,769, 2018).
Bottlenose Dolphin.......... Tursiops truncatus. Gulf of America -, -, N 20,759 (0.13, 167 36 Gulf RC........... Gulf RC Inshore... Civilian Ports:
Western Coastal. 18,585, 2018). Beaumont, TX,
Corpus Christi,
TX, Pascagoula,
MS; Coast Guard
Stations: Corpus
Christi, TX.
Bottlenose Dolphin.......... Tursiops truncatus. Florida Bay........ -, -, N UNK (UNK, UNK, UNK 0.2 Other AFTT Areas.. N/A............... N/A.
2003).
Bottlenose Dolphin.......... Tursiops truncatus. Indian River Lagoon -, -, Y 1,032 (0.03, 10 5.7 Other AFTT Areas.. JAX RC Inshore.... Civilian Ports:
Estuarine. 1,004, 2016-2017). Port Canaveral,
FL.
Bottlenose Dolphin.......... Tursiops truncatus. Jacksonville -, -, Y UNK (UNK, UNK, n/ UNK 2 JAX RC............ JAX RC Inshore.... Civilian Ports:
Estuarine. a). Port Canaveral,
FL.
Bottlenose Dolphin.......... Tursiops truncatus. MS Sound, Lake -, -, Y 1,265 (0.35, 947, 8.5 59 Gulf RC........... Gulf Inshore...... N/A.
Borgne, Bay 2018).
Boudreau.
Tamanend's bottlenose Tursiops erebennus. Western North -, -, Y 3,619 (0.35, 27 0.2 Other AFTT Areas.. JAX RC Inshore.... Civilian Ports:
Dolphin. Atlantic, Northern 2,711, 2021). Kings Bay, GA,
Florida Coastal. Savannah, GA.
Bottlenose Dolphin.......... Tursiops truncatus. Northern GA/ -, -, Y UNK (UNK, UNK, See UNK 1.5 Other AFTT Areas.. JAX RC Inshore.... N/A.
Southern SC SAR).
Estuarine.
Bottlenose Dolphin.......... Tursiops truncatus. Northern Gulf of -, -, N 63,280 (0.11, 556 65 Gulf RC........... N/A............... N/A.
America 57,917, 2018).
Continental Shelf.
Bottlenose Dolphin.......... Tursiops truncatus. Western North -, -, Y 6,639 (0.41, 48 12.2-21.5 VACAPES RC, Navy VACAPES RC Inshore Civilian Ports:
Atlantic, Northern 4,759, 2016). Cherry Point RC, Earle, NJ,
Migratory Coastal. JAX RC, Key West Delaware Bay, DE,
RC, Other AFTT Hampton Roads,
Areas. VA, Morehead
City, NC; Coast
Guard Stations:
Virginia Beach,
VA.
Bottlenose Dolphin.......... Tursiops truncatus. Northern NC -, -, Y 823 (0.06, 782, 7.8 7.2-30 Other AFTT Areas.. N/A............... Civilian Ports:
Estuarine. 2017). Morehead City,
NC, Wilmington,
NC.
Bottlenose Dolphin.......... Tursiops truncatus. Northern SC -, -, N 453 (0.28, 359, 3.6 0.5 Other AFTT Areas.. JAX RC Inshore.... N/A.
Estuarine. 2016).
Bottlenose Dolphin.......... Tursiops truncatus. Nueces Bay, Corpus -, -, Y 58 (0.61, UNK, UND 0.2 Gulf RC........... N/A............... Civilian Ports:
Christi. 1992). Corpus Christi,
TX.
Bottlenose Dolphin.......... Tursiops truncatus. Sabine Lake........ -, -, N 122 (0.19, 104, 0.9 0 Gulf RC........... N/A............... Civilian Ports:
2017). Beaumont, TX.

[[Page 19901]]

Tamanend's bottlenose Tursiops erebennus. Western North -, -, Y 9,121 (0.28, 73 0.2-0.6 Other AFTT Areas.. JAX RC Inshore.... Civilian Ports:
Dolphin. Atlantic South 7,261, 2021). Kings Bay, GA,
Carolina/Georgia Savannah, GA.
Coastal.
Bottlenose Dolphin.......... Tursiops truncatus. Southern GA -, -, N UNK (UNK, UNK, UND 0.1 Other AFTT Areas.. JAX RC Inshore.... Civilian Ports:
Estuarine System. 2008-2009). Kings Bay, GA,
Savannah, GA.
Bottlenose Dolphin.......... Tursiops truncatus. Western North -, -, Y 3,751 (0.6, 2,353, 24 0-18.3 Navy Cherry Point JAX RC Inshore.... Civilian Ports:
Atlantic, Southern 2016). RC, JAX RC, Key Hampton Roads,
Migratory Coastal. West RC, Other VA, Morehead
AFTT Areas. City, NC,
Wilmington, NC,
Kings Bay, GA,
Savannah, GA;
Coast Guard
Stations:
Virginia Beach,
VA.
Bottlenose Dolphin.......... Tursiops truncatus. Southern NC -, -, Y UNK (UNK, UNK, UND 0.4 Other AFTT Areas.. N/A............... Civilian Ports:
Estuarine System. 2017). Morehead City,
NC, Wilmington,
NC.
Bottlenose Dolphin.......... Tursiops truncatus. Western North -, -, N 64,587 (0.24, 507 28 Northeast RC, NUWC N/A............... Civilian Ports:
Atlantic Offshore 52,801, 2021). Division Newport Morehead City,
\17\. Testing Range, NC, Wilmington,
VACAPES RC, Navy NC.
Cherry Point RC,
JAX RC, Other
AFTT Areas.
Bottlenose Dolphin.......... Tursiops truncatus. Puerto Rico and -, -, Y UNK (UNK, UNK, N/ UNK UNK Other AFTT Areas.. N/A............... N/A.
U.S. Virgin A).
Islands.
Bottlenose Dolphin.......... Tursiops truncatus. Apalachee Bay...... -, -, Y 491 (0.39, UNK, UND 0 Gulf RC........... N/A............... N/A.
1993).
Bottlenose Dolphin.......... Tursiops truncatus. Barataria Bay -, -, Y 2,071 (0.06, 18 35 Gulf RC........... N/A............... N/A.
Estuarine System. 1,971, 2019).
Bottlenose Dolphin.......... Tursiops truncatus. Calcasieu Lake..... -, -, Y 0 (N/A, N/A, 1992) UND 0.2 Gulf RC........... N/A............... N/A.
Bottlenose Dolphin.......... Tursiops truncatus. Caloosahatchee -, -, Y 0 (N/A, N/A, 1985) UND 0.4 Gulf RC........... N/A............... N/A.
River.
Bottlenose Dolphin.......... Tursiops truncatus. Choctawhatchee Bay. -, -, Y 179 (0.04, UNK, UND 0.4 Gulf RC........... N/A............... N/A.
2007).
Bottlenose Dolphin.......... Tursiops truncatus. Chokoloskee Bay, -, -, Y UNK (N/A, UNK, N/ UND 0.2 Gulf RC........... N/A............... N/A.
Ten Thousand A).
Islands, Gullivan
Bay.
Bottlenose Dolphin.......... Tursiops truncatus. Copano Bay, Aransas -, -, Y 55 (0.82, UNK, UND 0.6 Gulf RC........... N/A............... Civilian Ports:
Bay, San Antonio 1992). Corpus Christi,
Bay, Redfish Bay, TX.
Espiritu Santo Bay.
Bottlenose Dolphin.......... Tursiops truncatus. Estero Bay......... -, -, Y UNK (N/A, UNK, N/ UND 0.4 Gulf RC........... N/A............... N/A.
A).
Bottlenose Dolphin.......... Tursiops truncatus. Florida Keys....... -, -, Y UNK (N/A, UNK, N/ UND 0.2 Gulf RC........... Key West Range N/A.
A). Complex Inshore.
Bottlenose Dolphin.......... Tursiops truncatus. Galveston Bay, East -, -, N 842 (0.08, 787, 6.3 1 Gulf RC........... N/A............... N/A.
Bay, Trinity Bay. 2016).
Bottlenose Dolphin.......... Tursiops truncatus. Laguna Madre....... -, -, Y 80 (1.57, UNK, UND 0.8 Gulf RC........... N/A............... N/A.
1992).
Bottlenose Dolphin.......... Tursiops truncatus. Matagorda Bay, Tres -, -, Y 61 (0.45, UNK, UND 0.4 Gulf RC........... N/A............... N/A.
Palacios Bay, 1992).
Lavaca Bay.
Bottlenose Dolphin.......... Tursiops truncatus. Mobile and -, -, Y 122 (0.34, UNK, UND 16 Gulf RC........... N/A............... N/A.
Bonsecour Bays. 1993).
Bottlenose Dolphin.......... Tursiops truncatus. MS River Delta..... -, -, N 1,446 (0.19, 11 9.2 Gulf RC........... N/A............... N/A.
1,238, 2018).
Bottlenose Dolphin.......... Tursiops truncatus. Pensacola and East -, -, Y 33 (0.8, UNK, UND 0.4 Gulf RC........... N/A............... N/A.
Bays. 1993).
Bottlenose Dolphin.......... Tursiops truncatus. Perdido Bay........ -, -, Y 0 (N/A, N/A, 1993) UND 0.8 Gulf RC........... N/A............... N/A.
Bottlenose Dolphin.......... Tursiops truncatus. Pine Island Sound, -, -, Y 826 (0.09, UNK, UND 1 Gulf RC........... N/A............... N/A.
Charlotte Harbor, 2006).
Gasparilla Sound,
Lemon Bay.
Bottlenose Dolphin.......... Tursiops truncatus. Sarasota Bays...... -, -, N 158 (0.27, 126, 1 0.2 Gulf RC........... N/A............... N/A.
2015).

[[Page 19902]]

Bottlenose Dolphin.......... Tursiops truncatus. St. Andrew Bay..... -, -, N 199 (0.09, 185, 1.5 0.2 Gulf RC........... Gulf Inshore...... N/A.
2016).
Bottlenose Dolphin.......... Tursiops truncatus. St. Joseph Bay..... -, -, N 142 (0.17, 123, 1 UNK Gulf RC........... N/A............... N/A.
2011).
Bottlenose Dolphin.......... Tursiops truncatus. St. Joseph Sound, -, -, Y UNK (N/A, UNK, N/ UND 0.8 Gulf RC........... N/A............... N/A.
Clearwater Harbor. A).
Bottlenose Dolphin.......... Tursiops truncatus. St. Vincent Sound, -, -, Y 439 (0.14, UNK, UND 0.2 Gulf RC........... N/A............... N/A.
Apalachicola Bay, 2007).
St. George Sound.
Bottlenose Dolphin.......... Tursiops truncatus. Tampa Bay.......... -, -, Y UNK (N/A, UNK, N/ UND 3 Gulf RC........... N/A............... Civilian Ports:
A). Tampa, FL.
Bottlenose Dolphin.......... Tursiops truncatus. Terrebonne and -, -, N 3,870 (0.15, 27 0.2 Gulf RC........... N/A............... N/A.
Timbalier Bays 3,426, 2016).
Estuarine System.
Bottlenose Dolphin.......... Tursiops truncatus. Vermillion Bay, -, -, Y 0 (N/A, N/A, 1992) UND 0 Gulf RC........... Gulf Inshore...... N/A.
West Cote Blanche
Bay, Atchafalaya
Bay.
Bottlenose Dolphin.......... Tursiops truncatus. Waccasassa Bay, -, -, Y UNK (N/A, UNK, N/ UND 0.4 Gulf RC........... N/A............... N/A.
Withlacoochee Bay, A).
Crystal Bay.
Bottlenose Dolphin.......... Tursiops truncatus. West Bay........... -, -, N 37 (0.05, 35, 0.3 0 Gulf RC........... N/A............... N/A.
2015).
Bottlenose Dolphin.......... Tursiops truncatus. Whitewater Bay..... -, -, Y UNK (N/A, UNK, N/ UND 0 Gulf RC........... N/A............... N/A.
A).
Clymene Dolphin............. Stenella clymene... Northern Gulf of -, -, Y 513 (1.03, 250, 2.5 8.4 Gulf RC, Other N/A............... N/A.
America. 2018). AFTT Areas.
Clymene Dolphin............. Stenella clymene... Western North -, -, N 21,778 (0.72, 126 0 Northeast RC, NUWC N/A............... N/A.
Atlantic. 12,622, 2021). Division, Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Common Dolphin.............. Delphinus delphis.. Western North -, -, N 93,100 (0.56, 1,452 414 Northeast RC, NUWC N/A............... N/A.
Atlantic. 59,897, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
False Killer Whale.......... Pseudorca Northern Gulf of -, -, N 494 (0.79, 276, 2.8 2.2 Gulf RC, Other N/A............... N/A.
crassidens. America. 2018). AFTT Areas.
False Killer Whale.......... Pseudorca Western North -, -, N 1,298 (0.72, 775, 7.6 0 NUWC Division, N/A............... N/A.
crassidens. Atlantic. 2021). Newport Testing
Range, VACAPES
RC, Navy Cherry
Point RC, JAX RC,
SFOMF, Key West
RC, NSWC Panama
City Division
Testing Range,
Gulf RC, Other
AFTT Areas.
Fraser's Dolphin............ Lagenodelphis hosei Northern Gulf of -, -, N 213 (1.03, 104, 1 UNK Gulf RC........... N/A............... N/A.
America. 2018).

[[Page 19903]]

Fraser's Dolphin............ Lagenodelphis hosei Western North -, -, N UNK (UNK, UNK, UNK 0 Northeast RC, NUWC N/A............... N/A.
Atlantic. 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Killer Whale................ Orcinus orca....... Northern Gulf of -, -, N 267 (0.75, 152, 1.5 UNK Gulf RC........... N/A............... N/A.
America. 2018).
Killer Whale................ Orcinus orca....... Western North -, -, N UNK (UNK, UNK, UNK 0 Northeast RC, NUWC N/A............... N/A.
Atlantic. 2016). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Long-Finned Pilot Whale..... Globicephala melas. Western North -, -, N 39,215 (0.30, 306 5.7 Northeast RC, NUWC N/A............... N/A.
Atlantic. 30,627, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Melon-Headed Whale.......... Peponocephala Northern Gulf of -, -, N 1,749 (0.68, 10 9.5 Gulf RC........... N/A............... N/A.
electra. America. 1,039, 2018).
Melon-Headed Whale.......... Peponocephala Western North -, -, N UNK (UNK, UNK, UNK 0 Northeast RC, NUWC N/A............... N/A.
electra. Atlantic. 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Pantropical Spotted Dolphin. Stenella attenuata. Northern Gulf of -, -, N 37,195 (0.24, 304 241 Gulf RC........... N/A............... N/A.
America. 30,377, 2018).
Pantropical Spotted Dolphin. Stenella attenuata. Western North -, D, N 2,757 (0.50, 19 0 Northeast RC, NUWC N/A............... N/A.
Atlantic. 1,856, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Pygmy Killer Whale.......... Feresa attenuata... Northern Gulf of -, -, N 613 (1.15, 283, 2.8 1.6 Gulf RC........... N/A............... N/A.
America. 2018).
Pygmy Killer Whale.......... Feresa attenuata... Western North -, -, N UNK (UNK, UNK, UNK 0 Northeast RC, NUWC N/A............... N/A.
Atlantic. 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Risso's Dolphin............. Grampus griseus.... Northern Gulf of -, -, N 1,974 (0.46, 14 5.3 Gulf RC........... N/A............... N/A.
America. 1,368, 2018).

[[Page 19904]]

Risso's Dolphin............. Grampus griseus.... Western North -, -, N 44,067 (0.19, 307 18 Northeast RC, NUWC N/A............... N/A.
Atlantic. 30,662, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Rough-Toothed Dolphin....... Steno bredanensis.. Northern Gulf of -, -, N UNK (N/A, UNK, UND 39 Gulf RC........... N/A............... N/A.
America. 2018).
Rough-Toothed Dolphin....... Steno bredanensis.. Western North -, -, N UNK (UNK, UNK, UND 0 Navy Cherry Point N/A............... N/A.
Atlantic. 2021). RC, JAX RC,
SFOMF, Key West
RC, NSWC Panama
City Division
Testing Range,
Gulf RC, Other
AFTT Areas.
Short-Finned Pilot Whale.... Globicephala Northern Gulf of -, -, N 1,321 (0.43, 934, 7.5 3.9 Gulf RC........... N/A............... N/A.
macrorhynchus. America. 2018).
Short-Finned Pilot Whale.... Globicephala Puerto Rico and -, -, Y UNK (UNK, UNK, N/ UNK UNK Other AFTT Areas.. N/A............... N/A.
macrorhynchus. U.S. Virgin A).
Islands.
Short-Finned Pilot Whale.... Globicephala Western North -, -, Y 18,726 (0.33, 143 218 Northeast RC, NUWC N/A............... N/A.
macrorhynchus. Atlantic. 14,292, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Spinner Dolphin............. Stenella Northern Gulf of -, -, Y 2,991 (0.54, 20 113 Gulf RC........... N/A............... N/A.
longirostris. America. 1,954, 2018).
Spinner Dolphin............. Stenella Puerto Rico and -, -, Y UNK (UNK, UNK, N/ UNK UNK Other AFTT Areas.. N/A............... N/A.
longirostris. U.S. Virgin A).
Islands.
Spinner Dolphin............. Stenella Western North -, D, N 3,181 (0.65, 19 0 Northeast RC, NUWC N/A............... N/A.
longirostris. Atlantic. 1,930, 2021). Division, Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Striped Dolphin............. Stenella Northern Gulf of -, -, Y 1,817 (0.56, 12 13 Gulf RC........... N/A............... N/A.
coeruleoalba. America. 1,172, 2018).
Striped Dolphin............. Stenella Western North -, -, N 48,274 (0.29, 529 0 Northeast RC, NUWC N/A............... N/A.
coeruleoalba. Atlantic. 38,040, 2021). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.

[[Page 19905]]

White-Beaked Dolphin........ Lagenorhynchus Western North -, -, N 536,016 (0.31, 4,153 0 Northeast RC, NUWC N/A............... N/A.
albirostris. Atlantic. 415,344, 2016). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC,
JAX RC, SFOMF,
Key West RC, NSWC
Panama City
Division Testing
Range, Gulf RC,
Other AFTT Areas.
Family Phocoenidae (porpoises):
Harbor Porpoise............. Phocoena phocoena.. Gulf of Maine/Bay -, -, N 85,765 (0.53, 649 142.4 Northeast RC, NUWC Northeast RC Civilian Ports:
of Fundy. 56,420, 2021). Division Newport Inshore, VACAPES Boston, MA,
Testing Range, RC Inshore, JAX Earle, NJ,
VACAPES RC, Navy RC Inshore. Delaware Bay, DE,
Cherry Point RC. Hampton Roads,
VA; Coast Guard
Stations: Boston,
MA, Virginia
Beach, VA.
Harbor Porpoise............. Phocoena phocoena.. Greenland.......... (18 19 20) .................. ......... ......... Other AFTT Areas..
Harbor Porpoise............. Phocoena phocoena.. Gulf of St. (18 19 20) .................. ......... ......... Other AFTT Areas..
Lawrence.
Harbor Porpoise............. Phocoena phocoena.. Newfoundland....... (18 19 20) .................. ......... ......... Other AFTT Areas..
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Pinnipedia
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
Gray Seal................... Halichoerus grypus. Western North -, -, N 27,911 (0.20, 756 4,491 Northeast RC, NUWC Northeast RC Civilian Ports:
Atlantic. 23,624, 2021). Division Newport Inshore, VACAPES Boston, MA,
Testing Range, RC Inshore, JAX Earle, NJ,
VACAPES RC, Navy RC Inshore. Delaware Bay, DE,
Cherry Point RC. Hampton Roads,
VA, Morehead
City, NC; Coast
Guard Stations:
Boston, MA,
Virginia Beach,
VA.
Harbor Seal................. Phoca vitulina..... Western North -, -, N 61,336 (0.08, 1,729 339 Northeast RC, NUWC Northeast RC Civilian Ports:
Atlantic. 57,637, 2018). Division Newport Inshore, VACAPES Boston, MA,
Testing Range, RC Inshore, JAX Earle, NJ,
VACAPES RC, Navy RC Inshore. Delaware Bay, DE,
Cherry Point RC. Hampton Roads,
VA, Morehead
City, NC; Coast
Guard Stations:
Boston, MA,
Virginia Beach,
VA.
Harp Seal................... Pagophilus Western North -, -, N 7.6M (UNK, 7.1M, 426,000 178,573 Northeast RC, NUWC N/A............... N/A.
groenlandicus. Atlantic. 2019). Division Newport
Testing Range,
VACAPES RC, Navy
Cherry Point RC.
Hooded Seal................. Cystophora cristata Western North -, -, N UNK (UNK, UNK, n/ UNK 1,680 Northeast RC, NUWC N/A............... Civilian Ports:
Atlantic. a). Division Newport Boston, MA.
Testing Range,
VACAPES RC, Navy
Cherry Point RC.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: %: percent; AFTT: Atlantic Fleet Training and Testing; CV: coefficient of variation; EEZ: Exclusive Economic Zone; EIS: Environmental Impact Statement; ESA: Endangered Species Act; JAX:
Jacksonville; Min.: minimum; MMPA: Marine Mammal Protection Act; NMFS: National Marine Fisheries Service; NSWC: Naval Surface Warfare Center; NUWC: Naval Undersea Warfare Center; RC: Range
Complex; SAR: Stock Assessment Report; SFOMF: Naval Surface Warfare Center, Carderock Division, South Florida Ocean Measurement Facility Testing Range; U.S.: United States; USFWS: U.S. Fish
and Wildlife Service; VACAPES: Virginia Capes. Marine mammals in the Gulf of America are named in the most recent SARs (Hayes et al., 2024) with reference to the formerly named ``Gulf of
Mexico.'' This Notice refers to these marine mammal stocks as Northern Gulf of America stocks. The geographical location of the stocks remains the same.
\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/).
\2\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or designated as depleted
under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or which is determined to be declining and likely to be listed under
the ESA within the foreseeable future. Any species or stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\3\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region. CV is coefficient of
variation; Nmin is the minimum estimate of stock abundance.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial fisheries, vessel strike). Annual M/SI
often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV associated with estimated mortality due to commercial fisheries is presented in some
cases.
\5\ NMFS uses ``credible interval'' to characterize the uncertainty as opposed to CV for North Atlantic right whales (Hayes et al., 2024).
\6\ Photo-ID catalog count of 402 recognizable blue whale individuals from the Gulf of St. Lawrence is considered a minimum population estimate for the western North Atlantic stock (Waring et
al., 2010). An additional 39 (0.64) were documented in the summer of 2016 for Central Virginia to Bay of Fundy (Waring et al., 2010).
\7\ The West Greenland stock of fin whales is not managed by NMFS and, therefore, does not have an associated Stock Assessment Report. Abundance and a 95% confidence interval were presented in
Heide-Jorgensen et al. (2010a).
\8\ The Gulf of St. Lawrence stock of fin whales is not managed by NMFS and, therefore, does not have an associated Stock Assessment Report. Abundance and 95% confidence interval were
presented in Ramp et al. (2014).
\9\ The West Greenland stock of minke whales is not managed by NMFS and, therefore, does not have an associated Stock Assessment Report. Abundance and 95% confidence interval were presented in
Heide-Jorgensen et al. (2010b).
\10\ Total M/SI is a minimum estimate and does not include Fisheries M/SI.
\11\ The Labrador Sea stock of sei whales is not managed by NMFS and, therefore, does not have an associated Stock Assessment Report. Information was obtained in Prieto et al. (2014).

[[Page 19906]]

\12\ Because Kogia sima and K. breviceps are difficult to differentiate at sea, the reported abundance estimates for the Western North Atlantic stock are for both species of Kogia combined.
\13\ Because Kogia sima and K. breviceps are difficult to differentiate at sea, the reported abundance estimates for the Northern Gulf of America stock are for both species of Kogia combined.
\14\ Estimate includes undifferentiated Mesoplodon species.
\15\ Estimate includes Gervais' and Blainville's beaked whales.
\16\ There are 32 stocks within the bottlenose dolphin Gulf of America Bay, Sound, and Estuaries strategic stock and there are no stock-specific SARs available at this time.
\17\ Estimate may include sightings of the coastal form.
\18\ Harbor porpoises in the Gulf of St. Lawrence are not managed by NMFS and have no associated Stock Assessment Report.
\19\ Harbor porpoises in Newfoundland are not managed by NMFS and have no associated Stock Assessment Report.
\20\ Harbor porpoises in Greenland are not managed by NMFS and have no associated Stock Assessment Report.

[[Page 19907]]

Species Not Included in the Analysis

The species carried forward for analysis (and described in table
14) are those likely to be found in the AFTT Study Area based on the
most recent data available and do not include species that may have
once inhabited or transited the area but have not been sighted in
recent years (e.g., species which were extirpated from factors such as
19th and 20th century commercial exploitation). Several species that
may be present in the northwestern Atlantic Ocean have an extremely low
probability of presence in the AFTT Study Area. These species are
considered extralimital (not anticipated to occur in the Study Area) or
rare (occur in the Study Area sporadically, but sightings are rare).
These extralimital species include the bowhead whale (Balaena
mysticetus), beluga whale (Delphinapterus leucas), narwhal (Monodon
monoceros), ringed seal (Pusa hispida), and bearded seal (Erignathus
barbatus). Bowhead whales are likely to be found only in the Labrador
Current open ocean area but, in 2012 and 2014, the same bowhead whale
was observed in Cape Cod Bay, which represents the southernmost record
of this species in the western North Atlantic. In June 2014, a beluga
whale was observed in several bays and inlets of Rhode Island and
Massachusetts (Swaintek, 2014). This sighting likely represents an
extralimital beluga whale occurrence in the Northeast United States
Continental Shelf Large Marine Ecosystem. Narwhals prefer cold Arctic
waters, and there is no stock of narwhal that occurs in the U.S. EEZ in
the Atlantic Ocean; however, populations from Hudson Strait and Davis
Strait may extend into the AFTT Study Area at its northwest extreme and
those that winter in Hudson Strait likely occur in smaller numbers.
In addition to the species listed above, several stocks that did
not overlap areas in or near modeled activities in the AFTT Study Area
were not analyzed. These stocks include the West Greenland and Gulf of
St. Lawrence stocks of fin whale; the West Greenland stock of minke
whale; the Labrador Sea stock of sei whale; and the Gulf of St.
Lawrence, Newfoundland, and Greenland stocks of harbor porpoise. NMFS
agrees with the Action Proponents' assessment that these species are
unlikely to occur in the AFTT Study Area, and they are not discussed
further. Further, neither NMFS nor Navy anticipates take of the Puerto
Rico/U.S. Virgin Islands stock of sperm whale, as U.S. Navy training
activities in the Vieques Naval Training Range ceased in 2003.
Three species of marine mammals, walrus (Odobenus rosmarus), West
Indian manatee (Trichechus manatus), and polar bear (Ursus maritimus),
occur in the AFTT Study Area, but are managed by the U.S. Fish and
Wildlife Service (U.S. FWS), and thus are not considered further in
this document.
Below, we consider additional information about the marine mammals
in the area of the specified activities that informs our analysis, such
as identifying known areas of important habitat or behaviors, or where
Unusual Mortality Events (UME) have been designated.

Critical Habitat

Currently, only the NARW has ESA-designated critical habitat in the
AFTT Study Area. However, NMFS has recently published a proposed rule
proposing new ESA-designated critical habitat for the Rice's whale (88
FR 47453, July 24, 2023).
North Atlantic Right Whale
On February 26, 2016, NMFS issued a final rule (81 FR 4838) to
replace the critical habitat for NARW with two new areas. The areas now
designated as critical habitat contain approximately 29,763 nmi\2\
(102,084 km\2\) of marine habitat in the Gulf of Maine and Georges Bank
region (Unit 1), essential for NARW foraging and off the Southeast U.S.
coast (Unit 2), including the coast of North Carolina, South Carolina,
Georgia, and Florida, which are key areas essential for calving. These
two ESA-designated critical habitats were established to replace three
smaller previously ESA-designated critical habitats (Cape Cod Bay/
Massachusetts Bay/Stellwagen Bank, Great South Channel, and the coastal
waters of Georgia and Florida in the southeastern United States) that
had been designated by NMFS in 1994 (59 FR 28805, June 3, 1994). Two
additional areas in Canadian waters, Grand Manan Basin and Roseway
Basin, were identified and designated as critical habitat under
Canada's endangered species law (section 58 (5) of the Species at Risk
Act (SARA), S. C. 2002, c. 29) and identified in Final Recovery
Strategy for the NARW, posted June 2009 on the SARA Public Registry.
Unit 1 encompasses the Gulf of Maine and Georges Bank region
including the large embayments of Cape Cod Bay and Massachusetts Bay
and deep underwater basins, as well as state waters, except for inshore
areas, bays, harbors, and inlets, from Maine through Massachusetts in
addition to Federal waters, all of which are key areas (see figure 4.1-
1 of the application). It also does not include waters landward of the
72 COLREGS lines (33 CFR part 80). The essential physical and
biological features of foraging habitat for NARW are: (1) The physical
oceanographic conditions and structures of the Gulf of Maine and
Georges Bank region that combine to distribute and aggregate Calanus
finmarchicus for right whale foraging, namely prevailing currents and
circulation patterns, bathymetric features (basins, banks, and
channels), oceanic fronts, density gradients, and temperature regimes;
(2) low flow velocities in Jordan, Wilkinson, and Georges Basins that
allow diapausing C. finmarchicus to aggregate passively below the
convective layer so that the copepods are retained in the basins; (3)
late stage C. finmarchicus in dense aggregations in the Gulf of Maine
and Georges Bank region; and (4) diapausing C. finmarchicus in
aggregations in the Gulf of Maine and Georges Bank region.
Unit 2 consists of all marine waters from Cape Fear, North
Carolina, southward to approximately 27 nmi below Cape Canaveral,
Florida, within the area bounded on the west by the shoreline and the
72 COLREGS lines, and on the east by rhumb lines connecting the
specific points described below (see figure 4.1-2 of the application).
The essential physical and biological features correlated with the
distribution of NARW in the southern critical habitat area provide an
optimum environment for calving. These are: (1) Calm sea surface
conditions of Force 4 or less on the Beaufort Wind Scale; (2) sea
surface temperatures from a minimum of 44.6 [deg]F (7 [deg]C), and
never more than 62.6 [deg]F (17 [deg]C); and (3) water depths of 19.7
to 91.9 ft (6 to 28 m), where these features simultaneously co-occur
over contiguous areas of at least 231 nmi\2\ (792.3 km\2\) of ocean
waters during the months of November through April. For example, the
bathymetry of the inner and nearshore middle shelf area minimizes the
effect of strong winds and offshore waves, limiting the formation of
large waves and rough water. The average temperature of critical
habitat waters is cooler during the time right whales are present due
to a lack of influence by the Gulf Stream and cool freshwater runoff
from coastal areas. The water temperatures may provide an optimal
balance between offshore waters that are too warm for nursing mothers
to tolerate, yet not too cool for calves that may only have minimal
fatty insulation. Reproductive females and calves are expected to be
concentrated in the critical habitat from December through April.

[[Page 19908]]

Rice's Whale
On August 23, 2021, NMFS published a final rule that revised the
listing of Rice's whales under the ESA to reflect the change in the
scientifically accepted taxonomy and nomenclature of this species (86
FR 47022). Prior to this revision, the Rice's whale was listed in 2019
under the ESA as an endangered subspecies of the Bryde's whale (Gulf of
America subspecies (referred to as the Gulf of Mexico subspecies in 86
FR 47022)). The 2019 listing rule indicated that, with a total
abundance of approximately 100 individuals, small population size and
restricted range are the most serious threats to this species (84 FR
15446, April 15, 2019). However, other threats such as energy
exploration, development, and production; oil spills and oil spill
responses; vessel collision; fishing gear entanglement; and
anthropogenic noise were also identified as threats that contribute to
the risk of extinction.
The specific occupied areas proposed for designation as critical
habitat for the Rice's whale contain approximately 28,270.65 mi\2\
(73,220.65 km\2\) of continental shelf and slope associated waters
between 100 m and 400 m (328 ft and 1,312 ft) isobaths within the Gulf
of America spanning from the U.S. EEZ boundary off the southwestern
coast of Texas, to the boundary between the South Atlantic Fishery
Management Council and the Gulf Fishery Management Council off the
southeastern coast of Florida.
In the final listing rule, NMFS stated that critical habitat was
not determinable at the time of the listing, because sufficient
information was not currently available on the geographical area
occupied by the species (84 FR 15446, April 15, 2019). On July 24,
2023, NMFS published a proposed rule describing the proposed critical
habitat designation, including supporting information on Rice's whale
biology, distribution, and habitat use, and the methods used to develop
the proposed designation (88 FR 47453). The physical and biological
features essential to the conservation of the species identified in the
proposed rule are:
(i) Sufficient density, quality, abundance, and accessibility of
small demersal and vertically migrating prey species, including
scombriformes, stomiiformes, myctophiformes, and myopsida;
(ii) Marine water with:
A. Elevated productivity,
B. Bottom temperatures of 50-66.2 [deg]F (10-19 [deg]C), and
C. Levels of pollutants that do not preclude or inhibit any
demographic function; and
(iii) Sufficiently quiet conditions for normal use and occupancy,
including intraspecific communication, navigation, and detection of
prey, predators, and other threats.

Biologically Important Areas

LaBrecque et al. (2015) identified Biologically Important Areas
(BIAs) within U.S. waters of the East Coast and Gulf of America, which
represent areas and times in which cetaceans are known to concentrate
in areas of known importance for activities related to reproduction,
feeding, and migration, or areas where small and resident populations
are known to occur. Unlike ESA critical habitat, these areas are not
formally designated pursuant to any statute or law, but are a
compilation of the best available science intended to inform impact and
mitigation analyses. An interactive map of the BIAs is available here:
https://oceannoise.noaa.gov/biologically-important-areas. In some
cases, additional, or newer, information regarding known feeding,
breeding, or migratory areas may be available, and is included below.
On the East Coast, 19 of the 24 identified BIAs fall within or
overlap with the AFTT Study Area: 10 feeding (2 for minke whale, 1 for
sei whale, 3 for fin whale, 3 for NARW, and 1 for humpback), 1
migration (NARW), 2 reproduction (NARW), and 6 small and resident
population (1 for harbor porpoise and 5 for bottlenose dolphin).
Figures 4.1-1 through 4.1-14 of the application illustrate how these
BIAs overlap with OPAREAs on the East Coast. In the Gulf of America, 4
of the 12 identified BIAs for small and resident populations overlap
the AFTT Study Area (1 for Rice's (Bryde's) whale and 3 for bottlenose
dolphin). Figures 4.1-9 through 4.1-13 of the application illustrates
how these BIAs overlap with OPAREAs in the Gulf of America.
Large Whales Feeding BIAs--East Coast
Two minke whale feeding BIAs are located in the northeast Atlantic
from March through November in waters less than 200 m (656 ft) in the
southern and southwestern section of the Gulf of Maine including
Georges Bank, the Great South Channel, Cape Cod Bay and Massachusetts
Bay, Stellwagen Bank, Cape Anne, and Jeffreys Ledge (LaBrecque et al.,
2015a; LaBrecque et al., 2015b). LaBrecque et al. (2015b) delineated a
feeding area for sei whales in the northeast Atlantic between the 25-m
(82-ft) contour off coastal Maine and Massachusetts to the 200-m (656-
ft) contour in central Gulf of Maine, including the northern shelf
break area of Georges Bank. The feeding area also includes the southern
shelf break area of Georges Bank from 100-2,000 m (328-6,562 ft) and
the Great South Channel. Feeding activity is concentrated from May
through November with a peak in July and August. LaBrecque et al.
(2015b) identified three feeding areas for fin whales in the North
Atlantic within the AFTT Study Area: (1) June to October in the
northern Gulf of Maine, (2) year-round in the southern Gulf of Maine,
and (3) March to October east of Montauk Point. LaBrecque et al.
(2015b) delineated a humpback whale feeding area in the Gulf of Maine,
Stellwagen Bank, and Great South Channel.
North Atlantic Right Whale BIAs--East Coast and Additional Information
LaBrecque et al. (2015b) identified three seasonal NARW feeding
areas BIAs located in or near the AFTT Study Area (1) February to April
on Cape Cod Bay and Massachusetts Bay, (2) April to June in the Great
South Channel and on the northern edge of Georges Bank, and (3) June to
July and October to December on Jeffreys Ledge in the western Gulf of
Maine. A mating BIA was identified in the central Gulf of Maine (from
November through January), a calving BIA in the southeast Atlantic
(from mid-November to late April), and the migratory corridor area BIA
along the U.S. East Coast between the NARW southern calving grounds and
northern feeding areas (see figures 4.1-1 through 4.1-14 of the
application for how these BIAs overlap with Navy OPAREAs).
In addition to the BIAs described above, an area south of Martha's
Vineyard and Nantucket, primarily along the western side of Nantucket
Shoals, was recently described as an important feeding area (Kraus et
al., 2016; O'Brien et al., 2022, Quintano-Rizzo et al., 2021). Its
importance as a foraging habitat is well established (Leiter et al.,
2017; Estabrook et al., 2022; O'Brien et al., 2022). Nantucket Shoals'
unique oceanographic and bathymetric features, including a persistent
tidal front, help sustain year-round elevated phytoplankton biomass and
aggregate zooplankton prey for NARW (White et al., 2020; Quintana-Rizzo
et al., 2021). O'Brien et al. (2022) hypothesize that NARW southern New
England habitat use has increased in recent years (i.e., over the last
decade) as a result of either, or a combination of, a northward shift
in prey distribution (thus increasing local prey availability) or a
decline in prey in other abandoned feeding areas (e.g., Gulf of Maine),
both induced by climate change. Pendleton et al. (2022) characterize
southern New

[[Page 19909]]

England as a ``waiting room'' for NARW in the spring, providing
sufficient, although sub-optimal, prey choices while NARW wait for C.
finmarchicus supplies in Cape Cod Bay (and other primary foraging
grounds like the Great South Channel) to optimize as seasonal primary
and secondary production progresses. Throughout the year, southern New
England provides opportunities for NARW to capitalize on C.
finmarchicus blooms or alternative prey (e.g., Pseudocalanus elongatus
and Centropages species, found in greater concentrations than C.
finmarchicus in winter), although likely not to the extent provided
seasonally in more well-understood feeding habitats like Cape Cod Bay
in late spring or the Great South Channel (O'Brien et al., 2022).
Although extensive data gaps, highlighted in a recent report by the
National Academy of Sciences (NAS) (2023), have prevented development
of a thorough understanding of NARW foraging ecology in the Nantucket
Shoals region, it is clear that the habitat was historically valuable
to the species based on historical whaling records, and observations
over the last decade confirm the area's importance as a feeding
habitat.
Harbor Porpoise BIA--East Coast
LaBrecque et al. (2015b) identified a small and resident population
BIA for harbor porpoise in the Gulf of Maine (see figure 4.1-14 of the
application). From July to September, harbor porpoises are concentrated
in waters less than 150 m (492 ft) deep in the northern Gulf of Maine
and southern Bay of Fundy. During fall (October to December) and spring
(April to June), harbor porpoises are widely dispersed from New Jersey
to Maine, with lower densities farther north and south (LaBrecque et
al., 2015b).
Bottlenose Dolphin BIA--East Coast
LaBrecque et al. (2015b) identified nine small and resident
bottlenose dolphin population areas within estuarine areas along the
east coast of the U.S. (see figure 4.1-11 of the application). These
areas include estuarine and nearshore areas extending from Pamlico
Sound, North Carolina down to Florida Bay, Florida (LaBrecque et al.,
2015b). The Northern North Carolina Estuarine System, Southern North
Carolina Estuarine System, and Charleston Estuarine System populations
partially overlap with nearshore portions of the Navy Cherry Point
Range Complex and Jacksonville Estuarine System Populations partially
overlaps with nearshore portions of the Jacksonville Range Complex. The
Southern Georgia Estuarine System Population area also overlaps with
the Jacksonville Range Complex, specifically within Naval Submarine
Base Kings Bay, Kings Bay, Georgia and includes estuarine and
intercoastal waterways from Altamaha Sound, to the Cumberland River
(LaBrecque et al., 2015b). The remaining four BIAs are outside but
adjacent to the AFTT Study Area boundaries.
Bottlenose Dolphin BIA--Gulf of America
LaBrecque et al. (2015) also described 11 year-round BIAs for small
and resident estuarine stocks of bottlenose dolphin that primarily
inhabit inshore waters of bays, sounds, and estuaries (BSE) in the Gulf
of America (see figures 4.1-12 and 4.1-13 in the application). Of the
11 BIAs identified for the BSE bottlenose dolphins in the Gulf of
America, three overlap with the Gulf Range Complex (Aransas Pass Area,
Texas; Mississippi Sound Area, Mississippi; and St. Joseph Bay Area,
Florida), while eight are located adjacent to the AFTT Study Area
boundaries.
Rice's (Previously Bryde's) Whale BIA--Gulf of America
The Rice's (previously Bryde's) whale is a very small population
that is genetically distinct from Bryde's whales and not genetically
diverse within the Gulf of America (Rosel and Wilcox, 2014; Rosel et
al., 2021). Further, the species is typically observed only within a
narrowly circumscribed area within the eastern Gulf of America.
Therefore, this area is described as a year-round BIA by LaBrecque et
al. (2015). Previous survey effort covered all oceanic waters of the
U.S. Gulf of America, and whales were observed only between
approximately the 100- and 300-m (328- and 984-ft) isobaths in the
eastern Gulf of America from the head of the De Soto Canyon (south of
Pensacola, Florida) to northwest of Tampa Bay, Florida (Maze-Foley and
Mullin, 2006; Waring et al., 2016; Rosel and Wilcox, 2014; Rosel et
al., 2016). Rosel et al. (2016) expanded this description by stating
that, due to the depth of some sightings, the area is more
appropriately defined to the 400-m (1,312-ft) isobath and westward to
Mobile Bay, Alabama, in order to provide some buffer around the deeper
sightings and to include all sightings in the northeastern Gulf of
America. Since then, passive acoustic detections of Rice's whale have
occurred in the north central and western Gulf of America (Soldevilla
et al., 2022; Soldevilla et al., 2024), although the highest densities
of Rice's whales have been confined to the northeastern Gulf of America
core habitat. The number of individuals that occur in the central and
western Gulf of America and nature of their use of this area is poorly
understood. Soldevilla et al. (2022) suggest that more than one
individual was present on at least one occasion, as overlapping calls
of different call subtypes were recorded in that instance, but also
state that call detection rates suggest that either multiple
individuals are typically calling or that individual whales are
producing calls at higher rates in the central and western Gulf of
America. Soldevilla et al. (2024) provide further evidence that Rice's
whale habitat encompasses all 100-400 m (328-1,312 ft) depth waters
encircling the entire Gulf of America, including Mexican waters (as
described in the proposed critical habitat designation (88 FR 47453,
July 24, 2023)), but they also note that further research is needed to
understand the density of whales in these areas, seasonal changes in
whale density, and other aspects of habitat usage.

National Marine Sanctuaries

Under Title III of the Marine Protection, Research, and Sanctuaries
Act of 1972 (also known as the National Marine Sanctuaries Act (NMSA)),
NOAA can establish as national marine sanctuaries (NMS) areas of the
marine environment with special conservation, recreational, ecological,
historical, cultural, archaeological, scientific, educational, or
aesthetic qualities. Sanctuary regulations prohibit destroying, causing
the loss of, or injuring any sanctuary resource managed under the law
or regulations for that sanctuary (15 CFR part 922). NMS are managed on
a site-specific basis, and each sanctuary has site-specific
regulations. Most, but not all sanctuaries have site-specific
regulatory exemptions from the prohibitions for certain military
activities. Separately, section 304(d) of the NMSA requires Federal
agencies to consult with the Office of National Marine Sanctuaries
whenever their Proposed Activities are likely to destroy, cause the
loss of, or injure a sanctuary resource. There are five designated NMSs
and one proposed NMS within the AFTT Study Area (see section 6.1.3 of
the 2024 AFTT Draft Supplemental EIS/OEIS). Two of these sanctuaries,
Flower Garden Banks NMS in the Gulf of America and Monitor NMS off of
North Carolina, do not inform our assessment of impacts to marine
mammals and their habitat.
Three NMSs and one proposed NMS within the AFTT Study Area are

[[Page 19910]]

associated with features that inform our assessment of impacts to
marine mammals and their habitat: Gerry E. Studds Stellwagen Bank NMS,
Gray's Reef NMS, Florida Keys NMS, and Hudson Canyon Proposed NMS.
Stellwagen Bank NMS sits at the mouth of Massachusetts Bay, 3 miles
(mi; 4.8 km) south of Cape Ann, 3 mi (4.8 km) north of Cape Cod and 25
mi (40.2 km) due east of Boston and provides feeding and nursery
grounds for marine mammals including NARW, humpback, sei, and fin
whales. The Stellwagen Bank NMS is within critical habitat for the NARW
for foraging (Unit 1). Gray's Reef NMS is 19 mi (30.6 km) east of
Sapelo Island Georgia, in the South Atlantic Bight (the offshore area
between Cape Hatteras, North Carolina and Cape Canaveral, Florida) and
is within the designated critical habitat for NARW calving in the
southeast (Unit 2). Florida Keys NMS protects 2,900 nmi\2\ (9,947
km\2\) of waters surrounding the Florida Keys, from south of Miami
westward to encompass the Dry Tortugas, excluding Dry Tortugas National
Park and supports a resident group of bottlenose dolphin (Florida Bay
Population BIA). The Office of National Marine Sanctuaries is in the
process of designating the Hudson Canyon NMS off the coast of New York
and New Jersey. Hudson Canyon is the largest submarine canyon along the
U.S. Atlantic coast and is one of the largest in the world. Beginning
approximately 100 mi (160.9 km) southeast of New York City, the canyon
extends about 350 mi (563.3 km) seaward, reaches depths of 2-2.5 mi
(3.2-4.0 km), and is up to 7.5 mi (12.1 km) wide. Hudson Canyon is
considered an ecological hotspot due to its size and diversity of
structures, including steep slopes, firm outcrops for invertebrates,
diverse sediments, flux of nutrients, and areas of upwelling that
support marine mammals and provides habitat for a range of endangered
and protected species, including sperm whales.

Unusual Mortality Events

An Unusual Mortality Event (UME) is defined under section 410(6) of
the MMPA as a stranding that is unexpected; involves a significant die-
off of any marine mammal population; and demands immediate response.
Three UMEs with ongoing investigations in the AFTT Study Area that
inform our analysis are discussed below. The 2022 Maine Pinniped UME
has closed, and the 2018 Northeast Pinniped UME is non-active and
pending closure.
North Atlantic Right Whale (2017-Present)
Beginning in 2017, elevated mortalities in NARW were documented in
Canada and the United States and necessitated an UME be declared. The
whales impacted by the UME include dead, injured, and sick individuals,
who represent more than 20 percent of the population, which is a
significant impact on an endangered species where deaths are outpacing
births. Additionally, research demonstrates that only about one third
of right whale deaths are documented. The preliminary cause of
mortality, serious injury, and morbidity (sublethal injury and illness)
in most of these whales is from entanglements or vessel strikes.
Endangered NARW are approaching extinction. There are approximately 372
individuals remaining, including fewer than 70 reproductively active
females. Human impacts continue to threaten the survival of this
species. The many individual whales involved in the UME are a
significant setback to the recovery of this endangered species.
Since 2017, dead, seriously injured, sublethally injured, or ill
NARW along the United States and Canadian coasts have been documented,
necessitating a UME declaration and investigation. The leading category
for the cause of death for this ongoing UME is ``human interaction,''
specifically from entanglements or vessel strikes. As of January 2,
2025, there have been 41 confirmed mortalities (dead, stranded, or
floating) and 39 seriously injured free-swimming whales for a total of
80 whales. The UME also considers animals with sublethal injury or
illness (i.e., ``morbidity''; n = 71) bringing the total number of
whales in the UME to 151. More information about the NARW UME is
available online at https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2025-north-atlantic-right-whale-unusual-mortality-event.
Humpback Whale (2017-Present)
Since January 2016, elevated humpback whale mortalities have
occurred along the Atlantic coast from Maine to Florida. This event was
declared a UME in April 2017. Partial or full necropsy examinations
have been conducted on approximately half of the 244 known cases (as of
February 6, 2025). Of the whales examined (approximately 90), about 40
percent had evidence of human interaction either from vessel strike or
entanglement. While a portion of the whales have shown evidence of pre-
mortem vessel strike, this finding is not consistent across all whales
examined, and more research is needed. NOAA is consulting with
researchers that are conducting studies on the humpback whale
populations, and these efforts may provide information on changes in
whale distribution and habitat use that could provide additional
insight into how these vessel interactions occurred. More information
is available at: https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2025-humpback-whale-unusual-mortality-event-along-atlantic-coast.
Minke Whale (2017-Present)
Elevated minke whale mortalities detected along the Atlantic coast
from Maine through South Carolina resulted in the declaration of an on-
going UME in 2017. As of February 10, 2025, a total of 198 minke whales
have stranded during this UME. Full or partial necropsy examinations
were conducted on more than 60 percent of the whales. Preliminary
findings show evidence of human interactions or infectious disease, but
these findings are not consistent across all of the minke whales
examined, so more research is needed. More information is available at:
https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2025-minke-whale-unusual-mortality-event-along-atlantic-coast.
Phocid Seals (2018-2020, 2022)
Harbor and gray seals have experienced two UMEs since 2018,
although one was recently closed (2022 Pinniped UME in Maine) and
closure of the other, described here, is pending. Beginning in July
2018, elevated numbers of harbor seal and gray seal mortalities
occurred across Maine, New Hampshire, and Massachusetts. Additionally,
stranded seals have shown clinical signs as far south as Virginia,
although not in elevated numbers, therefore the UME investigation
encompassed all seal strandings from Maine to Virginia. A total of
3,152 reported strandings (of all species) occurred from July 1, 2018,
through March 13, 2020. Full or partial necropsy examinations were
conducted on some of the seals and samples were collected for testing.
Based on tests conducted thus far, the main pathogen found in the seals
is phocine distemper virus. NMFS is performing additional testing to
identify any other factors that may be involved in this UME, which is
pending closure. Information on this UME is available online at:
https://www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2020-pinniped-unusual-mortality-event-along.

[[Page 19911]]

Deepwater Horizon Oil Spill

In 2010, the BP-operated Macondo well blowout and explosion aboard
the Deepwater Horizon drilling rig (also known as the Deepwater Horizon
explosion, oil spill, and response; hereafter referred to as the DWH
oil spill) caused oil, natural gas, and other substances to flow into
the Gulf of America for 87 days before the well was sealed. Total oil
discharge was estimated at 3.19 million barrels (134 million gallons),
resulting in the largest marine oil spill in history (DWH Natural
Resource Damage Assessment (NRDA) Trustees, 2016). In addition, the
response effort involved extensive application of dispersants at the
seafloor and at the surface, and controlled burning of oil at the
surface was also used extensively as a response technique. The oil,
dispersant, and burn residue compounds present ecological challenges in
the region.
At its maximum extent, oil covered over 15,444 mi\2\ (40,000 km\2\)
of ocean. Cumulatively, over the course of the spill, oil was detected
on over 43,243 mi\2\ (112,000 km\2\) of ocean. Currents, winds, and
tides carried these surface oil slicks to shore, fouling more than
1,304.9 mi (2,100 km) of shoreline, including beaches, bays, estuaries,
and marshes from eastern Texas to the Florida Panhandle. In addition,
some lighter oil compounds evaporated from the slicks, exposing air-
breathing organisms like marine mammals to noxious fumes at the sea
surface.
DWH oil was found to cause problems with the regulation of stress
hormone secretion from adrenal cells and kidney cells, which will
affect an animal's ability to regulate body functions and respond
appropriately to stressful situations, thus leading to reduced fitness.
Bottlenose dolphins living in habitats contaminated with DWH oil showed
signs of adrenal dysfunction, and dead, stranded dolphins from areas
contaminated with DWH oil had smaller adrenal glands (Schwacke et al.,
2014a; Venn-Watson et al., 2015b). Other factors were ruled out as a
primary cause for the high prevalence of adverse health effects,
reproductive failures, and disease in stranded animals. When all of the
data were considered together, the DWH oil spill was determined to be
the only reasonable cause for the full suite of observed adverse health
effects.
Due to the difficulty of investigating marine mammals in pelagic
environments and across the entire region impacted by the event, the
injury assessment focused on health assessments conducted on bottlenose
dolphins in nearshore habitats and used these populations as case
studies for extrapolating to coastal and oceanic populations that
received similar or worse exposure to DWH oil, with appropriate
adjustments made for differences in behavior, anatomy, physiology, life
histories, and population dynamics among species. Investigators then
used a population modeling approach to capture the overlapping and
synergistic relationships among the metrics for injury, and to quantify
the entire scope of DWH marine mammal injury to populations into the
future, expressed as ``lost cetacean years'' due to the DWH oil spill
(which represents years lost due to premature mortality as well as the
resultant loss of reproductive output). This approach allowed for
consideration of long-term impacts resulting from immediate losses and
reproductive failures in the few years following the spill, as well as
expected persistent impacts on survival and reproduction for exposed
animals well into the future (Takeshita et al., 2017; Smith et al.,
2022). For a more detailed overview of the injury quantification for
these stocks and their post-DWH population trajectory, please see
Schwacke et al. (2017) and Marques et al. (2023), and for full details
of the overall injury quantification, see DWH Marine Mammal Injury
Quantification Team (MMIQT) (2015).
The results of the quantification exercise for each affected shelf
and oceanic stock, and for northern and western coastal stocks of
bottlenose dolphin, are presented in table 15. This is likely a
conservative estimate of impacts, because: (1) Shelf and oceanic
species experienced long exposures (up to 90 days) to very high
concentrations of fresh oil and a diverse suite of response activities,
while estuarine dolphins were not exposed until later in the spill
period and to weathered oil products at lower water concentrations; (2)
oceanic cetaceans dive longer and to deeper depths, and it is possible
that the types of lung injuries observed in estuarine dolphins may be
more severe for oceanic cetaceans; and (3) cetaceans in deeper waters
were exposed to very high concentrations of volatile gas compounds at
the water's surface near the wellhead. No analysis was performed for
Fraser's dolphins or killer whales; although they are present in the
Gulf of America, sightings are rare and there were no historical
sightings in the oil spill footprint during the surveys used in the
quantification process. These stocks were likely injured, but no
information was available on which to base a quantification effort at
that time.

Table 15--Summary of Modeled Effects of the Deepwater Horizon Oil Spill
[DWH NRDA Trustees, 2016]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Percent of
Percent of Percent of Percent of population Percent of
population population females with with adverse maximum Years to
Common name Stock exposed to oil killed (95 reproductive health effects population recovery (95
(95 percent percent CI) failure (95 (95 percent reduction (95 percent CI) *
CI) percent CI) CI) percent CI)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rice's whale (formerly Bryde's Northern Gulf of 48 (23-100) 17 (7-24) 22 (10-31) 18 (7-28) -22 69
whale). America.
Sperm whale....................... Northern Gulf of 16 (11-23) 6 (2-8) 7 (3-10) 6 (2-9) -7 21
America.
Kogia spp......................... Multiple............ 15 (8-29) 5 (2-7) 7 (3-10) 6 (2-9) -6 11
Beaked whales..................... Multiple............ 12 (7-22) 4 (2-6) 5 (3-8) 4 (2-7) -6 10
Bottlenose dolphin................ Northern Gulf of 10 (5-10) 3 (1-5) 5 (2-6) 4 (1-6) -4 N/A
America, Oceanic.
Bottlenose dolphin................ Gulf of America, 82 (55-100) 38 (26-58) 37 (17-53) 30 (11-47) -50 (32-73) 39 (23-76)
Northern Coastal.

[[Page 19912]]

Bottlenose dolphin................ Gulf of America, 23 (16-32) 1 (1-2) 10 (5-15) 8 (3-13) -5 (3-9) N/A
Western Coastal.
Shelf dolphins **................. Multiple............ 13 (9-19) 4 (2-6) 6 (3-8) 5 (2-7) -3 N/A
Clymene dolphin................... Northern Gulf of 7 (3-15) 2 (1-4) 3 (2-5) 3 (1-4) -3 N/A
America.
False killer whale................ Northern Gulf of 18 (7-48) 6 (3-9) 8 (4-12) 7 (3-11) -9 42
America.
Melon-headed whale................ Northern Gulf of 15 (6-36) 5 (2-7) 7 (3-10) 6 (2-9) -7 29
America.
Pantropical spotted dolphin....... Northern Gulf of 20 (15-26) 7 (3-10) 9 (4-13) 7 (3-11) -9 39
America.
Pygmy killer whale................ Northern Gulf of 15 (7-33) 5 (2-8) 7 (3-10) 6 (2-9) -7 29
America.
Risso's dolphin................... Northern Gulf of 8 (5-13) 3 (1-4) 3 (2-5) 3 (1-4) -3 N/A
America.
Rough-toothed dolphin............. Northern Gulf of 41 (16-100) 14 (6-20) 19 (9-26) 15 (6-23) -17 54
America.
Short-finned pilot whale.......... Northern Gulf of 6 (4-9) 2 (1-3) 3 (1-40) 2 (1-3) -3 N/A
America.
Spinner dolphin................... Northern Gulf of 47 (24-91) 16 (7-23) 21 (10-30) 17 (6-27) -23 105
America.
Striped dolphin................... Northern Gulf of 13 (8-22) 5 (2-7) 6 (3-9) 5 (2-8) -6 14
America.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Table modified from the DWH NRDA Trustees (2016). CI = confidence interval, No CI was calculated for population reduction or years to recovery for
shelf or oceanic stocks. Marine mammals in the Gulf of America are named in DWH NRDA Trustees (2016) with reference to the formerly named ``Gulf of
Mexico.'' This Notice refers to these marine mammal stocks as Northern Gulf of America stocks. The geographical location of the stocks remains the
same.
* It is not possible to calculate years to recovery for stocks with maximum population reductions of less than or equal to 5 percent.
** Shelf dolphins includes Atlantic spotted dolphins and the shelf stock of bottlenose dolphins (20-200 m water depth). These two species were combined
because the abundance estimate used in population modeling was derived from aerial surveys and the species could not generally be distinguished from
the air.

However, a recent study by Frasier et al. (2024), using a widely-
spaced passive acoustic monitoring array, found that of eight groups
monitored from 2010-2020, seven groups experienced long-term density
declines, including beaked whales (up to 83 percent), small delphinids
(up to 43 percent), and sperm whales (up to 31 percent). These measured
density declines exceed model-predicted changes and do not suggest
recovery trends for affected species to date (Frasier et al., 2024).
Population consequences of 15 cetacean taxonomic units in pelagic and
continental shelf waters (not including killer whales, false killer
whales, and Fraser's dolphins) were assessed by Marques et al. (2023),
who found that the DWH oil spill had the greatest population impacts on
spinner dolphins, striped dolphins, sperm whales, oceanic bottlenose
dolphins, and Kogia species. The number of lost cetacean years was
highest for the shelf bottlenose dolphin population (32,584 years) and
pantropical spotted dolphin population (31,372 years) (Marques et al.,
2023).

Marine Mammal Hearing

Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995, Wartzok and
Ketten, 1999, Au and Hastings, 2008). To reflect this, Southall et al.
(2007), Southall et al. (2019) recommended that marine mammals be
divided into hearing groups based on directly measured (behavioral or
auditory evoked potential techniques) or estimated hearing ranges
(e.g., behavioral response data, anatomical modeling). NMFS (2024)
generalized hearing ranges were chosen based on the approximately 65-dB
threshold from the composite audiograms, previous analysis in NMFS
(2018), and/or data from Southall et al. (2007) and Southall et al.
(2019). We note that the names of two hearing groups and the
generalized hearing ranges of all marine mammal hearing groups have
been recently updated (NMFS, 2024) as reflected below in table 16.

Table 16--Marine Mammal Hearing Groups
[NMFS, 2024]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 36 ** kHz.
whales).

[[Page 19913]]

High-frequency (HF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
Very High-frequency (VHF) cetaceans 200 Hz to 165 kHz.
(true porpoises, Kogia, river
dolphins, Cephalorhynchid,
Lagenorhynchus cruciger & L.
australis).
Phocid pinnipeds (PW) (underwater) 40 Hz to 90 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 68 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on the ~65-dB threshold from composite
audiogram, previous analysis in NMFS (2018), and/or data from Southall
et al. (2007) and Southall et al. (2019). Additionally, animals are
able to detect very loud sounds above and below that ``generalized''
hearing range.
** The Action Proponents split the LF functional hearing group into LF
and VLF based on Houser et al., (2024) while NMFS Updated Technical
Guidance (NMFS, 2024) does not include these data. NMFS is aware these
data and data collected during a final field season by Houser et al.
(in prep) have implications for the generalized hearing range for low-
frequency cetaceans and their weighting function, however, as
described in the 2024 Updated Technical Guidance, it is premature for
us to propose any changes to our current Updated Technical Guidance.
Mysticete hearing data is identified as a special circumstance that
could merit reevaluating the acoustic criteria for low-frequency
cetaceans in the 2024 Updated Technical Guidance once the data from
the final field season is published. Therefore, we anticipate that
once the data are published, it will likely necessitate updating this
document (i.e., likely after the data gathered in the summer 2024
field season and associated analysis are published).

For more detail concerning these groups and associated frequency
ranges, please see NMFS (2024) for a review of available information.
The Navy adjusted these hearing groups using data from recent
hearing measurements in minke whales (Houser et al., 2024). These data
support separating mysticetes (the LF cetacean marine mammal hearing
group in table 16) into two hearing groups, which the Navy designates
as ``very low-frequency (VLF) cetaceans'' and ``low-frequency (LF)
cetaceans,'' which follows the recommendations of Southall et al.
(2019a). Within the Navy's adjusted hearing groups, the VLF cetacean
group contains the larger mysticetes (blue, fin, right, and bowhead
whales) and the LF cetacean group contains the mysticete species not
included in the VLF group (e.g., minke, humpback, gray, pygmy right
whales). Although there have been no direct measurements of hearing
sensitivity in the larger mysticetes included in Navy's VLF hearing
group, an audible frequency range of approximately 10 Hz to 30 kHz has
been estimated from measured vocalization frequencies, observed
responses to playback of sounds, and anatomical analyses of the
auditory system. The upper frequency limit of hearing in Navy's LF
hearing group has been estimated in a minke whale from direct
measurements of auditory evoked potentials (Houser et al., 2024).

Potential Effects of Specified Activities on Marine Mammals and Their
Habitat

This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take of Marine Mammals section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Preliminary Analysis and
Negligible Impact Determination section considers the content of this
section, the Estimated Take of Marine Mammals section, and the Proposed
Mitigation Measures section, to draw conclusions regarding the likely
impacts of these activities on the reproductive success or survivorship
of individuals and whether those impacts on individuals are likely to
adversely affect the species through effects on annual rates of
recruitment or survival.
The Action Proponents have requested authorization for the take of
marine mammals that may occur incidental to training and testing
activities in the AFTT Study Area. The Action Proponents analyzed
potential impacts to marine mammals from acoustic and explosive sources
and from vessel use in the application. NMFS carefully reviewed the
information provided by the Action Proponents and concurs with their
synthesis of science, along with independently reviewing applicable
scientific research and literature and other information to evaluate
the potential effects of the Action Proponents' activities on marine
mammals, which are presented in this section (see appendix D in the
2024 AFTT Draft Supplemental EIS/OEIS for additional information).
Other potential impacts to marine mammals from training and testing
activities in the AFTT Study Area were analyzed in the 2024 AFTT Draft
Supplemental EIS/OEIS, in consultation with NMFS as a cooperating
agency, and determined to be unlikely to result in marine mammal take.
Therefore, the Action Proponents have not requested authorization for
take of marine mammals incidental to other components of their proposed
Specified Activities, and we agree that incidental take is unlikely to
occur from those components. In this proposed rule, NMFS analyzes the
potential effects on marine mammals from the activity components that
may cause the take of marine mammals: exposure to acoustic or explosive
stressors including non-impulsive (sonar and other transducers, and
vibratory pile driving) and impulsive (explosives, impact pile driving,
and air guns) stressors and vessel movement.
For the purpose of MMPA incidental take authorizations, NMFS'
effects assessments serve four primary purposes: (1) to determine
whether the specified activities would have a negligible impact on the
affected species or stocks of marine mammals (based on whether it is
likely that the activities would adversely affect the species or stocks
through effects on annual rates of recruitment or survival); (2) to
determine whether the specified activities would have an unmitigable
adverse impact on the availability of the species or stocks for
subsistence uses; (3) to prescribe the permissible methods of taking
(i.e., Level B harassment (behavioral harassment and temporary
threshold shift (TTS)), Level A harassment (auditory (AUD INJ) and non-
auditory injury), serious injury, or mortality), including
identification of the number and types of take that could occur by
harassment, serious injury, or mortality, and to prescribe other means
of effecting the least practicable adverse impact on the species or
stocks and their habitat (i.e., mitigation measures); and (4) to
prescribe requirements pertaining to monitoring and reporting.

[[Page 19914]]

In this section, NMFS provides a description of the ways marine
mammals may be generally affected by these activities in the form of
mortality, physical injury, sensory impairment (permanent and temporary
threshold shifts and acoustic masking), physiological responses
(particular stress responses), behavioral disturbance, or habitat
effects. Explosives and vessel strikes, which have the potential to
result in incidental take by serious injury and/or mortality, will be
discussed in more detail in the Estimated Take of Marine Mammals
section. The Estimated Take of Marine Mammals section also discusses
how the potential effects on marine mammals from non-impulsive and
impulsive sources relate to the MMPA definitions of Level A Harassment
and Level B Harassment, and quantifies those effects that rise to the
level of a take. The Preliminary Analysis and Negligible Impact
Determination section assesses whether the proposed authorized take
would have a negligible impact on the affected species and stocks.

Potential Effects of Underwater Sound on Marine Mammals

The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far (ANSI, 1995). The sound level of an area is
defined by the total acoustical energy being generated by known and
unknown sources, which may include physical (e.g., waves, wind,
precipitation, earthquakes, ice, atmospheric sound), biological (e.g.,
sounds produced by marine mammals, fish, and invertebrates), and
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activities may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
Anthropogenic sounds cover a broad range of frequencies and sound
levels and can have a range of highly variable impacts on marine life,
from none or minor to potentially severe responses, depending on
received levels, duration of exposure, behavioral context, and various
other factors. The potential effects of underwater sound from active
acoustic sources can possibly result in one or more of the following:
temporary or permanent hearing impairment, other auditory injury, non-
auditory physical or physiological effects, behavioral disturbance,
stress, and masking (Richardson et al., 1995; Gordon et al., 2004;
Nowacek et al., 2007; Southall et al., 2007; G[ouml]tz et al., 2009,
Southall et al., 2019a). The degree of effect is intrinsically related
to the signal characteristics, received level, distance from the
source, and duration of the sound exposure. In general, sudden, high-
level sounds can cause auditory injury, as can longer exposures to
lower level sounds. Temporary or permanent loss of hearing can occur
after exposure to noise, and occurs almost exclusively for noise within
an animal's hearing range.
Richardson et al. (1995) described zones of increasing intensity of
effect that might be expected to occur, in relation to distance from a
source and assuming that the signal is within an animal's hearing
range. First is the area within which the acoustic signal would be
audible (potentially perceived) to the animal, but not strong enough to
elicit any overt behavioral or physiological response. The next zone
corresponds with the area where the signal is audible to the animal and
of sufficient intensity to elicit behavioral or physiological
responsiveness. Third is a zone within which, for signals of high
intensity, the received level is sufficient to potentially cause
discomfort or non-auditory injury to auditory systems. Overlaying these
zones to a certain extent is the area within which masking (i.e., when
a sound interferes with or masks the ability of an animal to detect a
signal of interest that is above the absolute hearing threshold) may
occur; the masking zone may be highly variable in size.
We also describe more severe potential effects (i.e., certain non-
auditory physical or physiological effects). Potential effects from
impulsive sound sources can range in severity from effects such as
behavioral disturbance or tactile perception to physical discomfort,
slight injury of the internal organs and the auditory system, or, in
the case of explosives, more severe injuries or mortality (Yelverton et
al., 1973). Non-auditory physiological effects or injuries that
theoretically might occur in marine mammals exposed to high levels of
underwater sound or as a secondary effect of extreme behavioral
responses (e.g., change in dive profile as a result of an avoidance
response) caused by exposure to sound include neurological effects,
bubble formation, resonance effects, and other types of organ or non-
auditory injury (Cox et al., 2006; Southall et al., 2007; Zimmer and
Tyack, 2007; Tal et al., 2015).
Hearing
Marine mammals have adapted hearing based on their biology and
habitat: amphibious marine mammals (e.g., pinnipeds that spend time on
land and underwater) have modified ears that allow them to hear both
in-air and in-water, while fully aquatic marine mammals (e.g.,
cetaceans that are always underwater) have specialized ear adaptations
for in-water hearing (Wartzok and Ketten, 1999). These adaptations
explain the variation in hearing ability and sensitivity among marine
mammals and have led to the characterization of marine mammal
functional hearing groups based on those sensitivities: very low-
frequency cetaceans (VLF group: blue, fin, right, and bowhead whales),
low-frequency cetaceans (LF group: minke, sei, Bryde's, Rice's,
humpback, gray, and pygmy right whales), high-frequency cetaceans (HF
group: sperm whales, beaked whales, killer whale, melon-headed whale,
false/pygmy killer whale, pilot whales, and some dolphin species), very
high-frequency cetaceans (VHF group: some dolphin species, porpoises,
Amazon River dolphin, Kogia species, Baiji, and La Plata dolphin),
sirenians (SI group: manatees, dugongs), otariids and other non-phocid
marine carnivores in water and in air (OCW and OCA groups: sea lion,
fur seal, walrus, otter), and phocids in water and in air (PCW and PCA
groups: true seals) (Southall et al., 2019c). In Phase III, VLF and LF
cetaceans were part of one, combined LF cetacean hearing group.
However, as described in the Navy's report ``Criteria and Thresholds
for U.S. Navy Acoustic and Explosive Effects Analysis (Phase 4)'' (U.S.
Department of the Navy, 2024), Houser et al. (2024) recently reported
hearing measurements for minke whales. The Action

[[Page 19915]]

Proponents incorporated these measurements, as well as Southall et al.
(2019c), into their analysis. They determined that the data support
dividing mysticetes into two separate hearing groups: VLF and LF
cetacean, and NMFS concurs (as described further in the Estimated Take
of Marine Mammals section), that this approach is appropriate for this
action.
The hearing sensitivity of marine mammals is also directional,
meaning the angle between an animal's position and the location of a
sound source impacts the animal's hearing threshold, thereby impacting
an animal's ability to perceive the sound emanating from that source.
This directionality is likely useful for determining the general
location of a sound, whether for detection of prey, predators, or
members of the same species, and can be dependent upon the frequency of
the sound (Accomando et al., 2020; Au and Moore, 1984; Byl et al.,
2016; Byl et al. 2019; Kastelein et al., 2005; Kastelein et al., 2019;
Popov and Supin, 2009).
Acoustic Signaling
An acoustic signal refers to the sound waves used to communicate
underwater, and marine mammals use a variety of acoustic signals for
socially important functions, such as communicating, as well as
biologically important functions, such as echolocating (Richardson et
al., 1995; Wartzok and Ketten, 1999). Acoustic signals used for
communication are lower frequency (i.e., 20 Hz to 30 kHz) than those
signals used for echolocation, which are high-frequency (approximately
10-200 kHz peak frequency) signals used by odontocetes to sense their
underwater environment. Lower frequency vocalizations used for
communication may have a specific, prominent fundamental frequency
(Brady et al., 2021) or have a wide frequency range, depending on the
functional hearing group and whether the marine mammal is vocalizing
in-water or in-air. Acoustic signals used for echolocation are high-
frequency, high-energy sounds with patterns and peak frequencies that
are often species-specific (Baumann-Pickering et al., 2013).
Marine mammal species typically produce sounds at frequencies
within their own hearing range, though auditory and vocal ranges do not
perfectly align (e.g., odontocetes may only hear a portion of the
frequencies of an echolocation click). Because determining a species
vocal range is easier than determining a species' hearing range, vocal
ranges are often used to infer a species' hearing range when species-
specific hearing data are not available (e.g., large whale species).
Hearing Loss and Auditory Injury
Marine mammals, like all mammals, lose their ability to hear over
time due to age-related degeneration of auditory pathways and sensory
cells of the inner ear. This natural, age-related hearing loss is
distinct from acute noise-induced hearing loss (M[oslash]ller, 2013).
Noise-induced hearing loss can be temporary (i.e., TTS) or permanent
(permanent threshold shift, PTS), and higher-level sound exposures are
more likely to cause PTS or other AUD INJ. For marine mammals, AUD INJ
is considered to be possible when sound exposures are sufficient to
produce 40 dB of TTS measured approximately 4 minutes after exposure
(U.S. Department of the Navy, 2024). Numerous studies have directly
examined noise-induced hearing loss in marine mammals by measuring an
animal's hearing threshold before and after exposure to intense sounds.
The difference between the post-exposure and pre-exposure hearing
thresholds is then used to determine the amount of TTS (in dB) that was
produced as a result of the sound exposure (see appendix D of the 2024
AFTT Draft Supplemental EIS/OEIS for additional details). The Navy used
these studies to generate exposure functions, which are predictions of
the onset of TTS or PTS based on sound frequency, level, and type
(continuous or impulsive), for each marine mammal functional hearing
group (U.S. Department of the Navy, 2024).
TTS can last from minutes or hours to days (i.e., there is recovery
back to baseline/pre-exposure hearing threshold), can occur within a
specific frequency range (i.e., an animal might only have a temporary
loss of hearing sensitivity within a limited frequency band of its
auditory range), and can be of varying amounts (e.g., an animal's
hearing sensitivity might be reduced by only 6 dB or reduced by 30 dB).
While there is no simple functional relationship between TTS and PTS or
other AUD INJ (e.g., neural degeneration), as TTS increases, the
likelihood that additional exposure to increased sound pressure level
(SPL) or duration will result in PTS or other injury also increases
(see the 2024 AFTT Draft Supplemental EIS/OEIS for additional
discussion). Exposure thresholds for the occurrence of AUD INJ, which
include the potential for PTS, as well as situations when AUD INJ
occurs without PTS, can therefore be defined based on a specific amount
of TTS; that is, although an exposure has been shown to produce only
TTS, we assume that any additional exposure may result in some AUD INJ.
The specific upper limit of TTS is based on experimental data showing
amounts of TTS that have not resulted in AUD INJ. In other words, we do
not need to know the exact functional relationship between TTS and AUD
INJ, we only need to know the upper limit for TTS before some AUD INJ
is possible. In severe cases of AUD INJ, there can be total or partial
deafness, while in most cases the animal has an impaired ability to
hear sounds in specific frequency ranges (Kryter, 1985).
The following physiological mechanisms are thought to play a role
in inducing auditory threshold shift: effects to sensory hair cells in
the inner ear that reduce their sensitivity; modification of the
chemical environment within the sensory cells; residual muscular
activity in the middle ear; displacement of certain inner ear
membranes; increased blood flow; and post-stimulatory reduction in both
efferent and sensory neural output (Southall et al., 2007). The
amplitude, duration, frequency, temporal pattern, and energy
distribution of sound exposure all can affect the amount of associated
threshold shift and the frequency range in which it occurs. Generally,
the amount of threshold shift, and the time needed to recover from the
effect, increase as amplitude and duration of sound exposure increases.
Human non-impulsive noise exposure guidelines are based on the
assumption that exposures of equal energy (the same SEL) produce equal
amounts of hearing impairment regardless of how the sound energy is
distributed in time (NIOSH, 1998). Previous marine mammal TTS studies
have also generally supported this equal energy relationship (Southall
et al., 2007). SEL is used to predict TTS in marine mammals and is
considered a good predictor of TTS for shorter duration exposures than
longer duration exposures. The amount of TTS increases with exposure
SPL and duration, and is correlated with SEL, but duration of the
exposure has a more significant effect on TTS than would be predicted
based on SEL alone (e.g., Finneran et al., 2010b; Kastak et al., 2007;
Kastak et al., 2005; Kastelein et al., 2014a; Mooney et al., 2009a;
Popov et al., 2014; Gransier and Kastelein, 2024). These studies
highlight the inherent complexity of predicting TTS onset in marine
mammals, as well as the importance of considering exposure duration
when assessing potential impacts.
Generally, TTS increases with SEL in a non-linear fashion, where
lower SEL exposures will elicit a steady rate of TTS increase while
higher SEL

[[Page 19916]]

exposures will either increase TTS more rapidly or plateau (Finneran,
2015; U.S. Department of the Navy, 2024). Additionally, with sound
exposures of equal energy, those that had lower SPL with longer
duration were found to induce TTS onset at lower levels than those of
higher SPL and shorter duration. Less threshold shift will occur from
intermittent sounds than from a continuous exposure with the same
energy (some recovery can occur between intermittent exposures) (Kryter
et al., 1966; Ward, 1997; Mooney et al., 2009a, 2009b; Finneran et al.,
2010; Kastelein et al., 2014; Kastelein et al., 2015). For example, one
short higher SPL sound exposure may induce the same impairment as one
longer lower SPL sound, which in turn may cause more impairment than a
series of several intermittent softer sounds with the same total energy
(Ward, 1997). Additionally, though TTS is temporary, very prolonged or
repeated exposure to sound strong enough to elicit TTS, or shorter-term
exposure to sound levels well above the TTS threshold, can cause AUD
INJ, at least in terrestrial mammals (Kryter, 1985; Lonsbury-Martin et
al., 1987).
Although TTS increases non-linearly in marine mammals, recovery
from TTS typically occurs in a linear fashion with the logarithm of
time (Finneran, 2015; Finneran et al., 2010a; Finneran et al., 2010b;
Finneran and Schlundt, 2013; Kastelein et al., 2012a; Kastelein et al.,
2012b; Kastelein et al., 2013a; Kastelein et al., 2014a; Kastelein et
al., 2014b; Kastelein et al., 2014c; Popov et al., 2014; Popov et al.,
2013; Popov et al., 2011; Muslow et al., 2023; Finneran et al., 2023).
Considerable variation has been measured in individuals of the same
species in both the amount of TTS incurred from similar SELs (Kastelein
et al., 2012a; Popov et al., 2013) and the time-to-recovery from TTS
(Finneran, 2015; Kastelein et al., 2019e). Many of these studies relied
on continuous sound exposures, but intermittent, impulsive sound
exposures have also been tested. The sound resulting from an explosive
detonation is considered an impulsive sound, but no direct measurements
of hearing loss from exposure to explosive sources have been made. Few
studies (Finneran et al., 2002; Lucke et al., 2009; Sills et al., 2020;
Muslow et al., 2023) using impulsive sounds have produced enough TTS to
make predictions about hearing loss due to this source type (see U.S.
Department of the Navy, 2024a). In general, predictions of TTS based on
SEL for this type of sound exposure are likely to overestimate TTS
because some recovery from TTS may occur in the quiet periods between
impulsive sounds--especially when the duty cycle is low. Peak SPL
(unweighted) is also used to predict TTS due to impulsive sounds
(Southall et al., 2007; Southall et al., 2019c; U.S. Department of the
Navy, 2024a).
In some cases, intense noise exposures have caused AUD INJ (e.g.,
loss of cochlear neuron synapses), despite thresholds eventually
returning to normal; i.e., it is possible to have AUD INJ without a
resulting PTS (e.g., Kujawa and Liberman, 2006, 2009; Kujawa, 2010;
Fernandez et al., 2015; Ryan et al., 2016; Houser, 2021). In these
situations, however, threshold shifts were 30-50 dB measured 24 hours
after the exposure; i.e., there is no evidence that an exposure
resulting in less than 40 dB TTS measured a few minutes after exposure
can produce AUD INJ. Therefore, an exposure producing 40 dB of TTS,
measured a few minutes after exposure, can also be used as an upper
limit to prevent AUD INJ; i.e., it is assumed that exposures beyond
those capable of causing 40 dB of TTS have the potential to result in
INJ (which may or may not result in PTS).
Irreparable damage to the inner or outer cochlear hair cells may
cause PTS; however, other mechanisms are also involved, such as
exceeding the elastic limits of certain tissues and membranes in the
middle and inner ears and resultant changes in the chemical composition
of the inner ear fluids (Southall et al., 2007). When AUD INJ occurs,
there is physical damage to the sound receptors in the ear, whereas TTS
represents primarily tissue fatigue and is reversible (Southall et al.,
2007). AUD INJ is permanent (i.e., there is incomplete recovery back to
baseline/pre-exposure levels) but also can occur in a specific
frequency range and amount as mentioned above for TTS. In addition,
other investigators have suggested that TTS is within the normal bounds
of physiological variability and tolerance and does not represent
physical injury (e.g., Ward, 1997). Therefore, NMFS does not consider
less than 40 dB of TTS to constitute AUD INJ. The NMFS Acoustic Updated
Technical Guidance (NMFS, 2024), which was used in the assessment of
effects for this rule, compiled, interpreted, and synthesized the best
available scientific information for noise-induced hearing effects for
marine mammals to derive updated thresholds for assessing the impacts
of noise on marine mammal hearing.
While many studies have examined noise-induced hearing loss in
marine mammals (see Finneran (2015) and Southall et al. (2019a) for
summaries), published data on the onset of TTS for cetaceans are
limited to the captive bottlenose dolphin, beluga, harbor porpoise, and
Yangtze finless porpoise, and for pinnipeds in water, measurements of
TTS are limited to harbor seals, elephant seals, California sea lions,
and bearded seals. These studies examine hearing thresholds measured in
marine mammals before and after exposure to intense sounds, which can
then be used to determine the amount of threshold shift at various
post-exposure times. NMFS has reviewed the available studies, which are
summarized below (see also the 2024 AFTT Draft Supplemental EIS/OEIS
which includes additional discussion on TTS studies related to sonar
and other transducers).
The method used to test hearing may affect the resulting
amount of measured TTS, with neurophysiological measures producing
larger amounts of TTS compared to psychophysical measures (Finneran et
al., 2007; Finneran, 2015; Finneran et al., 2023).
The amount of TTS varies with the hearing test frequency.
As the exposure SPL increases, the frequency at which the maximum TTS
occurs also increases (Kastelein et al., 2014b). For high-level
exposures, the maximum TTS typically occurs one-half to one octave
above the exposure frequency (Finneran et al., 2007; Mooney et al.,
2009a; Nachtigall et al., 2004; Popov et al., 2011; Popov et al., 2013;
Schlundt et al., 2000). The overall spread of TTS from tonal exposures
can therefore extend over a large frequency range (i.e., narrowband
exposures can produce broadband (greater than one octave) TTS).
The amount of TTS increases with exposure SPL and duration
and is correlated with SEL, especially if the range of exposure
durations is relatively small (Kastak et al., 2007; Kastelein et al.,
2014b; Popov et al., 2014). As the exposure duration increases,
however, the relationship between TTS and SEL begins to break down.
Specifically, duration has a more significant effect on TTS than would
be predicted on the basis of SEL alone (Finneran et al., 2010a; Kastak
et al., 2005; Mooney et al., 2009a). This means if two exposures have
the same SEL but different durations, the exposure with the longer
duration (thus lower SPL) will tend to produce more TTS than the
exposure with the higher SPL and shorter duration. In most acoustic
impact assessments, the scenarios of interest involve shorter duration
exposures than the marine mammal experimental data from which impact
thresholds are derived; therefore, use of SEL tends to

[[Page 19917]]

over-estimate the amount of TTS. Despite this, SEL continues to be used
in many situations because it is relatively simple, more accurate than
SPL alone, and lends itself easily to scenarios involving multiple
exposures with different SPL (Finneran, 2015).
Gradual increases of TTS may not be directly observable
with increasing exposure levels, before the onset of PTS (Reichmuth et
al., 2019). Similarly, PTS can occur without measurable behavioral
modifications (Reichmuth et al., 2019).
The amount of TTS depends on the exposure frequency.
Sounds at low frequencies, well below the region of best sensitivity,
are less hazardous than those at higher frequencies, near the region of
best sensitivity (Finneran and Schlundt, 2013). The onset of TTS--
defined as the exposure level necessary to produce 6 dB of TTS (i.e.,
clearly above the typical variation in threshold measurements)--also
varies with exposure frequency. At the low frequency end of a species'
hearing curve, onset-TTS exposure levels are higher compared to those
in the region of best sensitivity.
TTS can accumulate across multiple exposures, but the
resulting TTS will be less than the TTS from a single, continuous
exposure with the same SEL (Finneran et al., 2010a; Kastelein et al.,
2014b; Kastelein et al., 2015b; Mooney et al., 2009b). This means that
TTS predictions based on the total, cumulative SEL will overestimate
the amount of TTS from intermittent exposures such as sonars and
impulsive sources.
The amount of observed TTS tends to decrease with
increasing time following the exposure; however, the relationship is
not monotonic (i.e., increasing exposure does not always increase TTS).
The time required for complete recovery of hearing depends on the
magnitude of the initial shift; for relatively small shifts recovery
may be complete in a few minutes, while large shifts (e.g.,
approximately 40 dB) may require several days for recovery. Under many
circumstances TTS recovers linearly with the logarithm of time
(Finneran et al., 2010a, 2010b; Finneran and Schlundt, 2013; Kastelein
et al., 2012a; Kastelein et al., 2012b; Kastelein et al., 2013a;
Kastelein et al., 2014b; Kastelein et al., 2014c; Popov et al., 2011;
Popov et al., 2013; Popov et al., 2014). This means that for each
doubling of recovery time, the amount of TTS will decrease by the same
amount (e.g., 6 dB recovery per doubling of time).
Nachtigall et al. (2018) and Finneran (2018) describe the
measurements of hearing sensitivity of multiple odontocete species
(bottlenose dolphin, harbor porpoise, beluga, and false killer whale)
when a relatively loud sound was preceded by a warning sound. These
captive animals were shown to reduce hearing sensitivity when warned of
an impending intense sound. Based on these experimental observations of
captive animals, the authors suggest that wild animals may dampen their
hearing during prolonged exposures or if conditioned to anticipate
intense sounds. Finneran (2018) recommends further investigation of the
mechanisms of hearing sensitivity reduction in order to understand the
implications for interpretation of existing TTS data obtained from
captive animals, notably for considering TTS due to short duration,
unpredictable exposures.
Marine mammal hearing plays a critical role in communication with
conspecifics and in interpretation of environmental cues for purposes
such as predator avoidance and prey capture. Depending on the degree
(elevation of threshold in dB), duration (i.e., recovery time), and
frequency range of TTS, and the context in which it is experienced, TTS
can have effects on marine mammals ranging from discountable to serious
similar to those discussed in auditory masking, below. For example, a
marine mammal may be able to readily compensate for a brief, relatively
small amount of TTS in a non-critical frequency range that takes place
during a time where ambient noise is lower and there are not as many
competing sounds present. Alternatively, a larger amount and longer
duration of TTS sustained during a time when communication is critical
for successful mother/calf interactions could have more serious impacts
if it were in the same frequency band as the necessary vocalizations
and of a severity that impeded communication. The fact that animals
exposed to high levels of sound that would be expected to result in
this physiological response would also be expected to have behavioral
responses of a comparatively more severe or sustained nature is
potentially more significant than the simple existence of a TTS.
However, it is important to note that TTS could occur due to longer
exposures to sound at lower levels so that a behavioral response may
not be elicited.
Depending on the degree and frequency range, the effects of AUD INJ
on an animal could also range in severity, although it is considered
generally more serious than TTS because it is a permanent condition
(Reichmuth et al., 2019). Of note, reduced hearing sensitivity as a
simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without some cost to the animal.
As the amount of research on hearing sensitivity has grown, so,
too, has the understanding that marine mammals may be able to self-
mitigate, or protect, against noise-induced hearing loss. An animal may
learn to reduce or suppress their hearing sensitivity when warned of an
impending intense sound exposure, or if the duty cycle of the sound
source is predictable (Finneran, 2018; Finneran et al., 2024;
Nachtigall and Supin, 2013, 2014, 2015; Nachtigall et al., 2015;
Nachtigall et al., 2016a, 2018; Nachtigall et al., 2016b). This has
been shown with several species, including the false killer whale
(Nachtigall and Supin, 2013), bottlenose dolphin (Finneran, 2018;
Nachtigall and Supin, 2014, 2015; Nachtigall et al., 2016b), beluga
whale (Nachtigall et al., 2015), and harbor porpoise (Nachtigall et
al., 2016a). Additionally, Finneran et al. (2023) and Finneran et al.
(2024) found that odontocetes that had participated in TTS experiments
in the past could have learned from that experience and subsequently
protected their hearing during new sound exposure experiments.
Behavioral Responses
Behavioral responses to sound are highly variable and context-
specific (Nowacek et al., 2007; Southall et al., 2007; Southall et al.,
2019). Many different variables can influence an animal's perception of
and response to (nature and magnitude) an acoustic event. An animal's
prior experience with a sound or sound source affects whether it is
less likely (habituation, self-mitigation) or more likely
(sensitization) to respond to certain sounds in the future (animals can
also be innately predisposed to respond to certain sounds in certain
ways) (Southall et al., 2007; Southall et al., 2016; Finneran, 2018;
Finneran et al., 2024; Nachtigall & Supin, 2013, 2014, 2015; Nachtigall
et al., 2015; Nachtigall et al., 2016a, 2018; Nachtigall et al.,
2016b). Related to the sound itself, the perceived proximity of the
sound, bearing of the sound (approaching vs. retreating), the
similarity of a sound to biologically relevant sounds in the animal's
environment (i.e., calls of predators, prey, or conspecifics),
familiarity of the sound, and navigational constraints may affect the
way an animal responds to the sound (Ellison et al., 2011; Southall et
al.,

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2007, DeRuiter et al., 2013, Southall et al., 2021; Wartzok et al.,
2003). Individuals (of different age, gender, reproductive status,
etc.) among most populations will have variable hearing capabilities,
and differing behavioral sensitivities to sounds that will be affected
by prior conditioning, experience, and current activities of those
individuals. Southall et al. (2007) and Southall et al. (2021) have
developed and subsequently refined methods developed to categorize and
assess the severity of acute behavioral responses, considering impacts
to individuals that may consequently impact populations. Often,
specific acoustic features of the sound and contextual variables (i.e.,
proximity, duration, or recurrence of the sound or the current behavior
that the marine mammal is engaged in or its prior experience), as well
as entirely separate factors such as the physical presence of a nearby
vessel, may be more relevant to the animal's response than the received
level alone.
Studies by DeRuiter et al. (2012) indicate that variability of
responses to acoustic stimuli depends not only on the species receiving
the sound and the sound source, but also on the social, behavioral, or
environmental contexts of exposure. Another study by DeRuiter et al.
(2013) examined behavioral responses of goose-beaked whales to MF sonar
and found that whales responded strongly at low received levels (89-127
dB re 1 [micro]Pa) by ceasing normal fluking and echolocation, swimming
rapidly away, and extending both dive duration and subsequent non-
foraging intervals when the sound source was 2.1-5.9 mi (3.4-9.5 km)
away. Importantly, this study also showed that whales exposed to a
similar range of received levels (78-106 dB re 1 [micro]Pa) from
distant sonar exercises 73.3 mi (118 km away) did not elicit such
responses, suggesting that context may moderate responses.
Ellison et al. (2012) outlined an approach to assessing the effects
of sound on marine mammals that incorporates contextual-based factors.
The authors recommend considering not just the received level of sound,
but also the activity the animal is engaged in at the time the sound is
received, the nature and novelty of the sound (i.e., is this a new
sound from the animal's perspective), and the distance between the
sound source and the animal. They submit that this ``exposure
context,'' as described, greatly influences the type of behavioral
response exhibited by the animal. Forney et al. (2017) also point out
that an apparent lack of response (e.g., no displacement or avoidance
of a sound source) may not necessarily mean there is no cost to the
individual or population, as some resources or habitats may be of such
high value that animals may choose to stay, even when experiencing
stress or hearing loss. Forney et al. (2017) recommend considering both
the costs of remaining in an area of noise exposure such as TTS, PTS,
or masking, which could lead to an increased risk of predation or other
threats or a decreased capability to forage, and the costs of
displacement, including potential increased risk of vessel strike,
increased risks of predation or competition for resources, or decreased
habitat suitable for foraging, resting, or socializing. This sort of
contextual information is challenging to predict with accuracy for
ongoing activities that occur over large spatial and temporal expanses.
However, distance is one contextual factor for which data exist to
quantitatively inform a take estimate, and the method for predicting
Level B harassment in this rule does consider distance to the source.
Other factors are often considered qualitatively in the analysis of the
likely consequences of sound exposure, where supporting information is
available.
Friedlaender et al. (2016) provided the first integration of direct
measures of prey distribution and density variables incorporated into
across-individual analyses of behavior responses of blue whales to
sonar, and demonstrated a five-fold increase in the ability to quantify
variability in blue whale diving behavior. These results illustrate
that responses evaluated without such measurements for foraging animals
may be misleading, which again illustrates the context-dependent nature
of the probability of response.
Exposure of marine mammals to sound sources can result in, but is
not limited to, no response or any of the following observable
responses: increased alertness; orientation or attraction to a sound
source; vocal modifications; cessation of feeding; cessation of social
interaction; alteration of movement or diving behavior; habitat
abandonment (temporary or permanent); and, in severe cases, panic,
flight, stampede, or stranding, potentially resulting in death
(Southall et al., 2007). A review of marine mammal responses to
anthropogenic sound was first conducted by Richardson (1995). More
recent reviews (Nowacek et al., 2007; DeRuiter et al., 2012 and 2013;
Ellison et al., 2012; Gomez et al., 2016) address studies conducted
since 1995 and focused on observations where the received sound level
of the exposed marine mammal(s) was known or could be estimated. Gomez
et al. (2016) conducted a review of the literature considering the
contextual information of exposure in addition to received level and
found that higher received levels were not always associated with more
severe behavioral responses and vice versa. Southall et al. (2016)
state that results demonstrate that some individuals of different
species display clear yet varied responses, some of which have negative
implications, while others appear to tolerate high levels, and that
responses may not be fully predictable with simple acoustic exposure
metrics (e.g., received sound level). Rather, the authors state that
differences among species and individuals along with contextual aspects
of exposure (e.g., behavioral state) appear to affect response
probability (Southall et al., 2019). The following subsections provide
examples of behavioral responses to stressors that provide an idea of
the variability in responses that would be expected given the
differential sensitivities of marine mammal species to sound and the
wide range of potential acoustic sources to which a marine mammal may
be exposed. Behavioral responses that could occur for a given sound
exposure should be determined from the literature that is available for
each species (see section D.6.5 (Behavioral Reactions) of the 2024 AFTT
Draft Supplemental EIS/OEIS for a comprehensive list of behavioral
studies and species-specific findings), or extrapolated from closely
related species when no information exists, along with contextual
factors.
Responses Due to Sonar and Other Transducers--
Mysticetes responses to sonar and other duty-cycled tonal sounds
are dependent upon the characteristics of the signal, behavioral state
of the animal, sensitivity and previous experience of an individual,
and other contextual factors including distance of the source, movement
of the source, physical presence of vessels, time of year, and
geographic location (Goldbogen et al., 2013; Harris et al., 2019a;
Harris et al., 2015; Martin et al., 2015; Sivle et al., 2015b). For
example, a behavioral response study (BRS) in Southern California
demonstrated that individual behavioral state was critically important
in determining response of blue whales to Navy sonar. In this BRS, some
blue whales engaged in deep (greater than 164 ft (50 m)) feeding
behavior had greater dive responses than those in shallow feeding or
non-feeding conditions, while some blue whales that were engaged in
shallow feeding behavior demonstrated

[[Page 19919]]

no clear changes in diving or movement even when received levels were
high (approximately 160 dB re 1 [micro]Pa) from exposures to 3-4 kHz
sonar signals, while others showed a clear response at exposures at
lower received level of sonar and pseudorandom noise (Goldbogen et al.,
2013). Generally, behavioral responses were brief and of low to
moderate severity, and the whales returned to baseline behavior shortly
after the end of the acoustic exposure (DeRuiter et al., 2017;
Goldbogen et al., 2013; Southall et al., 2019c). To better understand
the context to these behavioral responses, Friedlaender et al. (2016)
mapped the prey field of the deep-diving blue whales and found that the
response to sound was more apparent for individuals engaged in feeding
than those that were not. The probability of a moderate behavioral
response increased when the source was closer for these foraging blue
whales, although there was a high degree of uncertainty in that
relationship (Southall et al., 2019b). In the same BRS, none of the
tagged fin whales demonstrated more than a brief or minor response
regardless of their behavioral state (Harris et al., 2019a). The fin
whales were exposed to both mid-frequency simulated sonar and
pseudorandom noise of similar frequency, duration, and source level.
They were less sensitive to disturbance than blue whales, with no
significant differences in response between behavioral states or signal
types. The authors rated responses as low-to-moderate severity with no
negative impact to foraging success (Southall et al., 2023).
Similarly, while the rates of foraging lunges decrease in humpback
whales due to sonar exposure, there was variability in the response
across individuals, with one animal ceasing to forage completely and
another animal starting to forage during the exposure (Sivle et al.,
2016). In addition, almost half of the animals that exhibited avoidance
behavior were foraging before the exposure, but the others were not;
the animals that exhibited avoidance behavior while not feeding
responded at a slightly lower received level and greater distance than
those that were feeding (Wensveen et al., 2017). These findings
indicate that the behavioral state of the animal plays a role in the
type and severity of a behavioral response. Henderson et al. (2019)
examined tagged humpback whale dive and movement behavior, including
individuals incidentally exposed to Navy sonar during training
activities, at the Pacific Missile Range Facility off Kaua'i, Hawaii.
Tracking data showed that, regardless of exposure to sonar, individual
humpbacks spent limited time, no more than a few days, in the vicinity
of Kaua'i. Potential behavioral responses due to sonar exposure were
limited and may have been influenced by breeding and social behaviors.
Martin et al. (2015) found that the density of calling minke whales was
reduced during periods of Navy training involving sonar relative to the
periods before training began and increased again in the days following
the completion of training activities. The responses of individual
whales could not be assessed, so in this case it is unknown whether the
decrease in calling animals indicated that the animals left the range
or simply ceased calling. Harris et al. (2019b) utilized acoustically
generated minke whale tracks to statistically demonstrate changes in
the spatial distribution of minke whale acoustic presence before,
during, and after surface ship MFAS training. The spatial distribution
of probability of acoustic presence was different in the ``during''
phase compared to the ``before'' phase, and the probability of presence
at the center of ship activity during MFAS training was close to zero
for both years. The ``after'' phases for both years retained lower
probabilities of presence suggesting the return to baseline conditions
may take more than five days. The results show a clear spatial
redistribution of calling minke whales during surface ship MFAS
training, however a limitation of passive acoustic monitoring is that
one cannot conclude if the whales moved away, went silent, or a
combination of the two.
Building on this work, Durbach et al. (2021) used the same data and
determined that individual minke whales tended to be in either a fast
or slow movement behavior state while on the missile range, where
whales tended to be in the slow state in baseline or before periods but
transitioned into the fast state with more directed movement during
sonar exposures. They also moved away from the area of sonar activity
on the range, either to the north or east depending on where the
activity was located; this explains the spatial redistribution found by
Harris et al. (2019b). Minke whales were also more likely to stop
calling when in the fast state, regardless of sonar activity, or when
in the slow state during sonar activity (Durbach et al., 2021).
Similarly, minke whale detections were reduced or ceased altogether
during periods of sonar use off Jacksonville, Florida, (Norris et al.,
2012; Simeone et al., 2015; U.S. Department of the Navy, 2013),
especially with an increased ping rate (Charif et al., 2015).
Odontocetes have varied, context-dependent behavioral responses to
sonar and other transducers. Much of the research on odontocetes has
been focused on understanding the impacts of sonar and other
transducers on beaked whales because they were hypothesized to be more
susceptible to behavioral disturbance after several strandings of
beaked whales in which military MFAS was identified as a contributing
factor (see Stranding and Mortality section). Subsequent BRSs have
shown beaked whales are likely more sensitive to disturbance than most
other cetaceans. Many species of odontocetes have been studied during
BRSs, including Blainville's beaked whale, goose-beaked whale, Baird's
beaked whale, northern bottlenose whale, harbor porpoise, pilot whale,
killer whale, sperm whale, false killer whale, melon-headed whale,
bottlenose dolphin, rough-toothed dolphin, Risso's dolphin, Pacific
white-sided dolphin, and Commerson's dolphin. Observed responses by
Blainville's beaked whales, goose-beaked whales, Baird's beaked whales,
and northern bottlenose whales (the largest of the beaked whales), to
mid-frequency sonar sounds include cessation of clicking, decline in
group vocal periods, termination of foraging dives, changes in
direction to avoid the sound source, slower ascent rates to the
surface, longer deep and shallow dive durations, and other unusual dive
behaviors (DeRuiter et al., 2013b; Hewitt et al., 2022; Jacobson et
al., 2022; McCarthy et al., 2011; Miller et al., 2015; Moretti et al.,
2014; Southall et al., 2011; Stimpert et al., 2014; Tyack et al.,
2011).
During a BRS in Southern California, a tagged Baird's beaked whale
exposed to simulated MFA sonar within 3 km increased swim speed and
modified its dive behavior (Stimpert et al., 2014). One goose-beaked
whale was also incidentally exposed to real Navy sonar located over
62.1 mi (100 km) away in addition to the source used in the controlled
exposure study, and the authors did not detect similar responses at
comparable received levels. Received levels from the MFA sonar signals
from the controlled (2.1 to 5.9 mi (3.4 to 9.5 km)) exposures were
calculated as 84-144 dB re 1 [mu]Pa, and incidental (73.3 mi (118 km))
exposures were calculated as 78-106 dB re 1 [mu]Pa, indicating that
context of the exposures (e.g., source proximity, controlled source
ramp-up) may have been a significant factor in the responses to the
simulated sonars (DeRuiter et al., 2013b).

[[Page 19920]]

Long-term tagging work during the same BRS demonstrated that the
longer duration dives considered a behavioral response by DeRuiter et
al. (2013b) fell within the normal range of dive durations found for
eight tagged goose-beaked whales on the Southern California Offshore
Range (Schorr et al., 2014). However, the longer inter-deep dive
intervals found by DeRuiter et al. (2013b), which were among the
longest found by Schorr et al. (2014) and Falcone et al. (2017), may
indicate a response to sonar. Williams et al. (2017) note that during
normal deep dives or during fast swim speeds, beaked whales and other
marine mammals use strategies to reduce their stroke rates (e.g.,
leaping, wave surfing when swimming, interspersing glides between bouts
of stroking when diving). The authors determined that in the post-
exposure dives by the tagged goose-beaked whales described in DeRuiter
et al. (2013b), the whales ceased gliding and swam with almost
continuous strokes. This change in swim behavior was calculated to
increase metabolic costs about 30.5 percent and increase the amount of
energy expending on fast swim speeds from 27-59 percent of their
overall energy budget. This repartitioning of energy was detected in
the model up to 1.7 hours after the single sonar exposure. Therefore,
while the overall post-exposure dive durations were similar, the
metabolic energy calculated by Williams et al. (2017) was higher.
However, Southall et al. (2019a) found that prey availability was
higher in the western area of the Southern California Offshore Range
where goose-beaked whales preferentially occurred, while prey resources
were lower in the eastern area and moderate in the area just north of
the Range. This high prey availability may indicate that goose-beaked
whales need fewer foraging dives to meet energy requirements than would
be needed in another area with fewer resources.
During a BRS in Norway, northern bottlenose whales avoided a sonar
sound source over a wide range of distances (0.5 to 17.4 mi (0.8 to 28
km)) and estimated avoidance thresholds ranging from received SPLs of
117 to 126 dB re 1 [mu]Pa. The behavioral response characteristics and
avoidance thresholds were comparable to those previously observed in
beaked whale studies; however, researchers did not observe an effect of
distance on behavioral response and found that onset and intensity of
behavioral response were better predicted by received SPL. There was
one instance where an individual northern bottlenose whale approached
the vessel, circled the sound source (source level was only 122 dB re 1
[mu]Pa), and resumed foraging after the exposure. Conversely, one
northern bottlenose whale exposed to a sonar source was documented
performing the longest and deepest dive on record for the species, and
continued swimming away from the source for more than 7 hours (Miller
et al., 2015; Siegal et al., 2022; Wensveen et al., 2019).
Research on Blainville's beaked whales at the Atlantic Undersea
Test and Evaluation Center (AUTEC) range has shown that individuals
move off-range during sonar use, only returning after the cessation of
sonar transmission (Boyd et al., 2009; Henderson et al., 2015; Jones-
Todd et al., 2021; Manzano-Roth et al., 2022; Manzano-Roth et al.,
2016; McCarthy et al., 2011; Tyack et al., 2011). Five Blainville's
beaked whales estimated to be within 1.2 to 18 mi (2 to 29 km) of the
AUTEC range at the onset of active sonar were displaced a maximum of
17.4 to 42.3 mi (28 to 68 km) after moving away from the range,
although one individual did approach the range during active sonar use.
Researchers found a decline in deep dives at the onset of the training
and an increase in time spent on foraging dives as whales moved away
from the range. Predicted received levels at which presumed responses
were observed were comparable to those previously observed in beaked
whale studies. Acoustic data indicated that vocal periods were detected
on the range within 72 hours after training ended (Joyce et al., 2019).
However, Blainville's beaked whales have been documented to remain on-
range to forage throughout the year (Henderson et al., 2016),
indicating the AUTEC range may be a preferred foraging habitat
regardless of the effects of active sonar noise, or it could be that
there are no long-term consequences of the sonar activity. In the SOCAL
Range Complex, researchers conducting photo-identification studies have
identified approximately 100 individual goose-beaked whales, with 40
percent having been seen in one or more prior years, with re-sightings
up to 7 years apart, indicating a possible on-range resident population
(Falcone & Schorr, 2014; Falcone et al., 2009).
The probability of Blainville's beaked whale group vocal periods on
the Pacific Missile Range Facility were modeled during periods of (1)
no naval activity, (2) naval activity without hull-mounted MFA sonar,
and (3) naval activity with hull-mounted MFA sonar (Jacobson et al.,
2022). At a received level of 150 dB re 1 [mu]Pa RMS, the probability
of detecting a group vocal period during MFA sonar use decreased by 77
percent compared to periods when general training activity was ongoing,
and by 87 percent compared to baseline (no naval activity) conditions.
Jacobsen et al (2022) found a greater reduction in probability of a
group vocal period with MFA sonar than observed in a prior study of the
same species at the AUTEC range (Moretti et al., 2014), which may be
due to the baseline period in the AUTEC study including naval activity
without MFA sonar, potentially lowering the baseline group vocal period
activity in that study, or due to differences in the residency of the
populations at each range.
Stanistreet et al. (2022) used passive acoustic recordings during a
multinational navy activity to assess marine mammal acoustic presence
and behavioral response to especially long bouts of sonar lasting up to
13 consecutive hours, occurring repeatedly over 8 days (median and
maximum SPL = 120 dB and 164 dB). Goose-beaked whales and sperm whales
substantially reduced how often they produced clicks during sonar,
indicating a decrease or cessation in foraging behavior. Few previous
studies have shown sustained changes in foraging or displacement of
sperm whales, but there was an absence of sperm whale clicks for 6
consecutive days of sonar activity. Sperm whales returned to baseline
levels of clicks within days after the activity, but beaked whale
detection rates remained low even 7 days after the exercise. In
addition, there were no detections from a Mesoplodon beaked whale
species within the area during, and at least 7 days after, the sonar
activity. Clicks from northern bottlenose whales and Sowerby's beaked
whales were also detected but were not frequent enough at the recording
site used to compare clicks between baseline and sonar conditions.
Goose-beaked whale behavioral responses (i.e., deep and shallow
dive durations, surface interval durations, inter-deep dive intervals)
on the Southern California Anti-Submarine Warfare Range were modeled
against predictor values that included helicopter dipping sonar, mid-
power MFA sonar and hull-mounted, high-power MFA sonar along with other
non-MFA sonar predictors (Falcone et al., 2017). They found both
shallow and deep dive durations increased as the proximity to both mid-
and high-powered sources decreased, and found that surface intervals
and inter-deep dive intervals increased in the presence of both types
of sonars (helicopter dipping and hull-mounted), although surface
intervals shortened during

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periods without MFA sonar. Proximity of source and receiver were
important considerations, as the responses to the mid-power MFA sonar
at closer ranges were comparable to the responses to the higher source
level vessel sonar, as was the context of the exposure. Helicopter
dipping sonars are shorter duration and randomly located, therefore
more difficult to predict or track by beaked whales and potentially
more likely to elicit a response, especially at closer distances (3.7
to 15.5 mi (6 to 25 km))(Falcone et al., 2017). Sea floor depths and
quantity of light (i.e., lunar cycle) are also important variables to
consider in BRSs, as goose-beaked whale foraging dive depth increased
with sea floor depth (maximum 6,561.7 ft (2,000 m)) and the amount of
time spent at foraging depths (and likely foraging) was greater at
night (likely avoiding predation by staying deeper during periods of
bright lunar illumination), although they spent more time near the
surface during the night, as well, particularly on dark nights with
little moonlight, (Barlow et al., 2020). Sonar occurred during 10
percent of the dives studied and had little effect on the resulting
dive metrics. Watwood et al. (2017) found that the longer the duration
of a sonar event, the greater reduction in detected goose-beaked whale
group dives and, as helicopter dipping events occurred more frequently
but with shorter durations than periods of hull-mounted sonar, when
looking at the number of detected group dives there was a greater
reduction during periods of hull-mounted sonar than during helicopter
dipping sonar. DiMarzio et al. (2019) also found that group vocal
periods (i.e., clusters of foraging pulses), on average, decreased
during sonar events on the Southern California Anti-Submarine Warfare
Range, though the decline from before the event to during the event was
significantly less for helicopter dipping events than hull-mounted
events, and there was no difference in the magnitude of the decline
between vessel-only events and events with both vessels and
helicopters. Manzano-Roth et al. (2022) analyzed long-term passive
acoustic monitoring data from the Pacific Missile Range Facility in
Kaua'i, Hawaii, and found beaked whales reduced group vocal periods
during submarine command course events and remained low for a minimum
of 3 days after the MFA sonar activity.
Harbor porpoise behavioral responses have been researched
extensively using acoustic deterrent and acoustic harassment devices;
however, BRSs using sonar are limited. Kastelein et al. (2018b) found
harbor porpoises did not respond to low-duty cycle mid-frequency sonar
tones (3.5-4.1 kHz at 2.7 percent duty cycle; e.g., one tone per
minute) at any received level, but one individual did respond (i.e.,
increased jumping, increased respiration rates) to high-duty cycle
sonar tones (3.5-4.1 kHz at 96 percent duty cycle; e.g., continuous
tone for almost a minute).
Behavioral responses by odontocetes (other than beaked whales and
harbor porpoises) to sonar and other transducers include horizontal
avoidance, reduced breathing rates, changes in behavioral state,
changes in dive behavior (Antunes et al., 2014; Isojunno et al., 2018;
Isojunno et al., 2017; Isojunno et al., 2020; Miller, 2012; Miller et
al., 2011; Miller et al., 2014), and, in one study, separation of a
killer whale calf from its group (Miller et al., 2011). Some species of
dolphin (e.g., bottlenose, spotted, spinner, Clymene, Pacific white-
sided, rough-toothed) are frequently documented bowriding with vessels
and the drive to engage in bowriding, whether for pleasure or energetic
savings (Fiori et al., 2024) may supersede the impact of associated
sonar noise (W[uuml]rsig et al., 1998).
In controlled exposure experiments on captive odontocetes, Houser
et al., (2013a) recorded behavioral responses from bottlenose dolphins
with 3 kHz sonar-like tones between 115-185 dB re 1 [mu]Pa, and
individuals across 10 trials demonstrated a 50 percent probability of
response at 172 dB re 1 [mu]Pa. Multiple studies have been conducted on
bottlenose dolphins and beluga whales to measure TTS (Finneran et al.,
2003a; Finneran et al., 2001; Finneran et al., 2005; Finneran &
Schlundt, 2004; Schlundt et al., 2000). During these studies, when
individuals were presented with 1-second tones up to 203 dB re 1
[mu]Pa, responses included changes in respiration rate, fluke slaps,
and a refusal to participate or return to the location of the sound
stimulus, including what appeared to be deliberate attempts by animals
to avoid a sound exposure or to avoid the location of the exposure site
during subsequent tests (Finneran et al., 2002; Schlundt et al., 2000).
Bottlenose dolphins exposed to more intense 1-second tones exhibited
short-term changes in behavior above received levels of 178-193 dB re 1
[mu]Pa, and beluga whales did so at received levels of 180-196 dB re 1
[mu]Pa and above.
While several opportunistic observations of odontocete (other than
beaked whales and harbor porpoises) responses have been recorded during
previous Navy activities and BRSs that employed sonar and sonar-like
sources, it is difficult to definitively attribute responses of non-
focal species to sonar exposure. Responses range from no response to
potential highlight-impactful responses, such as the separation of a
killer whale calf from its group (Miller et al., 2011). This may be
due, in part, to the variety of species and sensitivities of the
odontocete taxonomic group, as well as the breadth of study types
conducted and field observations, leading to the assessment of both
contextually driven and dose-based responses. The available data
indicate exposures to sonar in close proximity and with multiple
vessels approaching an animal likely lead to higher-level responses by
most odontocete species, regardless of received level or behavioral
state. However, when sources are further away and moving in variable
directions, behavioral responses are likely driven by behavioral state,
individual experience, or species-level sensitivities, as well as
exposure duration and received level, with the likelihood of response
increasing with increased received levels. As such, it is expected
odontocete behavioral responses to sonar and other transducers will
vary by species, populations, and individuals, and long-term
consequences or population-level effects are likely dependent upon the
frequency and duration of the exposure and resulting behavioral
response.
Pinniped behavioral response to sonar and other transducers is
context-dependent (e.g., Hastie et al., 2014; Southall et al., 2019).
All studies on pinniped response to sonar thus far have been limited to
captive animals, though, based on exposures of wild pinnipeds to vessel
noise and impulsive sounds (see Responses Due to Vessel Noise section
and Responses Due to Impulsive Noise section below), pinnipeds may only
respond strongly to military sonar that is in close proximity or
approaching an animal. Kvadsheim et al. (2010b) found that captive
hooded seals exhibited avoidance response to sonar signals between 1-7
kHz (160 to 170 dB re 1 [micro]Pa rms) by reducing diving activity,
rapid surface swimming away from the source, and eventually moving to
areas of least SPL. However, the authors noted a rapid adaptation in
behavior (passive surface floating) during the second and subsequent
exposures, indicating a level of habituation within a short amount of
time. Kastelein et al. (2015c) exposed captive harbor seals to three
different sonar signals at 25 kHz with variable waveform
characteristics and duty cycles and found individuals responded

[[Page 19922]]

to a frequency modulated signal at received levels over 137 dB re 1
[micro]Pa by hauling out more, swimming faster, and raising their heads
or jumping out of the water. However, seals did not respond to a
continuous wave or combination signals at any received level (up to 156
dB re 1 [micro]Pa). Houser et al. (2013a) conducted a study to
determine behavioral responses of captive California sea lions to MFA
sonar at various received levels (125 to 185 dB re 1 [micro]Pa). They
found younger animals (less than 2 years old) were more likely to
respond than older animals and responses included increased respiration
rate, increased time spent submerged, refusal to participate in a
repetitive task, and hauling out. Most responses below 155 dB re 1
[micro]Pa were changes in respiration, while more severe responses
(i.e., refusing to participate, hauling out) began to occur over 170 dB
re 1 [micro]Pa, and many of the most severe responses came from the
young sea lions.
Responses Due to Impulsive Noise--
Impulsive signals have a rapid rise time and higher instantaneous
peak pressure than other signal types, particularly at close range,
which means they are more likely to cause startle or avoidance
responses. At long distances, however, the rise time increases as the
signal duration lengthens (similar to a ``ringing'' sound), making the
impulsive signal more similar to a non-impulsive signal (Hastie et al.,
2019; Martin et al., 2020). Behavioral responses from explosive sounds
are likely to be similar to responses studied for other impulsive
noise, such as those produced by air guns and impact pile driving. Data
on behavioral responses to impulsive sound sources are limited across
all marine mammal groups, with only a few studies available for
mysticetes and odontocetes.
Mysticetes have varied responses to impulsive sound sources,
including avoidance, aggressive directed movement towards the source,
reduced surface intervals, altered swimming behavior, and changes in
vocalization rates (Gordon et al., 2003; McCauley et al., 2000a;
Richardson et al., 1985; Southall et al., 2007). Studies have been
conducted on many baleen whale species, including gray, humpback, blue,
fin and bowhead whales; it is assumed that these responses are
representative of all baleen whale species. The behavioral state of the
whale seems to be an integral part of whether the animal responds and
how they respond, as does the location and movement of the sound
source, more than the received level of the sound.
If an individual is engaged in migratory behavior, it may be more
likely to respond to impulsive noise, and some species may be more
sensitive than others. Migrating gray whales showed avoidance responses
to seismic vessels at received levels between 164 and 190 dB re 1
[mu]Pa (Malme et al., 1986, Malme et al., 1988). In one study, McCauley
et al. (1998) found that migrating humpback whales in Australia showed
avoidance behavior at ranges of 3.1-5 mi (5-8 km) from a seismic array
during observational studies and controlled exposure experiments, and
another study found humpback whales in Australia decreased their dive
times and reduced their swimming speeds (Dunlop et al., 2015). However,
when comparing received levels and behavioral responses between air gun
ramp-up versus constant noise level of air guns, humpback whales did
not change their dive behavior but did deviate from their predicted
heading and decreased their swim speeds, deviating more during the
constant noise source trials but reducing swim speeds more during ramp-
up trials (Dunlop et al., 2016). In both cases, there was no dose-
response relationship with the received level of the air gun noise, and
similar responses were observed in control trials without air guns
(vessel movement remained constant across trials), so some responses
may have been due to vessel presence and not received level from the
air guns. Social interactions between males and mother-calf pairs were
reduced in the presence of vessels towing seismic air gun arrays,
regardless of whether the air guns were active or not; which indicates
that it was likely the presence of vessels (rather than the impulsive
noise generated from active air guns) that affected humpback whale
behavior (Dunlop et al., 2020).
Proximity of the impulsive source is another important factor to
consider when assessing the potential for behavioral responses in
marine mammals. Dunlop et al. (2017) found that groups of humpback
whales were more likely to avoid a smaller air gun array at closer
proximity than a larger air gun array, despite the same received level,
showing the difference in response between arrays has more to do with
the combined effects of received level and source proximity. In this
study, responses were varied and generally small, with short-term
course deviations of about 1,640 ft (500 m). Studies on bowhead whales
have shown they may be more sensitive than other species to impulsive
noise, as individuals have shown clear changes in diving and breathing
patterns up to 45.4 mi (73 km) from seismic vessels with received
levels as low as 125 dB re 1 [mu]Pa (Malme et al. 1988). Richardson et
al. (1995b) documented bowhead whales exhibiting avoidance behaviors at
a distance of more than 12.4 mi (20 km) from seismic vessels when
received levels were as low as 120 dB re 1 [mu]Pa, although most did
not show active avoidance until 5 mi (8 km) from the source. Although
bowhead whales may avoid the area around seismic surveys, from 3.7 to 5
mi (6 to 8 km) (Koski and Johnson 1987, as cited in Gordon et al.,
2003) out to 12.4 or 18.6 mi (20 or 30 km) (Richardson et al., 1999), a
study by Robertson et al. (2013) supports the idea that behavioral
responses are contextually dependent, and that during seismic
operations, bowhead whales may be less ``available'' for counting due
to alterations in dive behavior but that they may not have completely
vacated the area.
In contrast, noise from seismic surveys was not found to impact
feeding behavior or exhalation rates in western gray whales while
resting or diving off the coast of Russia (Gailey et al., 2007;
Yazvenko et al., 2007); however, the increase in vessel traffic
associated with surveys and the proximity of the vessels to the whales
did affect the orientation of the whales relative to the vessels and
shortened their dive-surface intervals (Gailey et al., 2016). They also
increased their speed and distance from the noise source and have been
documented in one case study swimming towards shore to avoid an
approaching seismic vessel (Gailey et al., 2022). Todd et al. (1996)
found no clear short-term behavioral responses by foraging humpbacks to
explosions associated with construction operations in Newfoundland but
did see a trend of increased rates of net entanglement closer to the
noise source, possibly indicating a reduction in net detection
associated with the noise through masking or TTS. Distributions of fin
and minke whales were modeled with multiple environmental variables and
with the occurrence or absence of seismic surveys, and no evidence of a
decrease in sighting rates relative to seismic activity was found for
either species (Vilela et al., 2016). Their distributions were driven
entirely by environmental variables, particularly those linked to prey,
including warmer sea surface temperatures, higher chlorophyll-a values,
and higher photosynthetically available radiation (a measure of primary
productivity). Sighting rates based on over 8,000 hours of baleen and
toothed whale survey data were compared on regular vessel

[[Page 19923]]

surveys versus both active and passive periods of seismic surveys
(Kavanagh et al., 2019). Models of sighting numbers were developed, and
it was determined that baleen whale sightings were reduced by 88
percent during active and 87 percent during inactive phases of seismic
surveys compared to regular surveys. These results seemed to occur
regardless of geographic location of the survey; however, when only
comparing active versus inactive periods of seismic surveys the
geographic location did seem to affect the change in sighting rates.
Mysticetes seem to be the most behaviorally sensitive taxonomic
group of marine mammals to impulsive sound sources, with possible
avoidance responses occurring out to 18.6 mi (30 km) and vocal changes
occurring in response to sounds over 62.1 mi (100 km) away. However,
they are also the most studied taxonomic group, yielding a larger
sample size and greater chance of finding behavioral responses to
impulsive noise. Also, their responses appear to be behavior-dependent,
with most avoidance responses occurring during migration behavior and
little observed response during feeding behavior. These response
patterns are likely to hold true for impulsive sources used by the
Action Proponents; however, their impulsive sources would largely be
stationary (e.g., explosives fired at a fixed target, small air guns),
and short term (hours rather than days or weeks) versus those in the
aforementioned studies, so responses would likely occur in closer
proximity to animals or not at all.
Odontocete responses to impulsive noise are not well studied and
the majority of data have come from seismic (i.e., air gun) surveys,
pile driving, and construction activities, while only a few studies
have been done to understand how explosive sounds impact odontocetes.
What data are available show they may be less sensitive than mysticetes
to impulsive sound and that responses occur at closer distances. This
may be due to the predominance of low-frequency sound associated with
impulsive sources that propagates across long distances and overlaps
with the range of best hearing for mysticetes but is below that range
for odontocetes. Even harbor porpoises--shown to be highly sensitive to
most sound sources, avoiding both stationary (e.g., pile driving) and
moving (e.g., seismic survey vessels) impulsive sound sources out to
approximately 12.4 mi (20 km) (e.g., Haelters et al., 2014; Pirotta et
al., 2014)--have short-term responses, returning to an area within
hours upon cessation of the impulsive noise.
Although odontocetes are generally considered less sensitive,
impulsive noise does impact toothed whales in a variety of ways. In one
study, dolphin detections were compared during 30 second periods
before, during, and after underwater detonations near naval mine
neutralization exercises in VACAPES. Lammers et al. (2017) found that
within 30 seconds after an explosion, the immediate response was an
increase in whistles compared to the 30 seconds before an explosion,
and that there was a reduction in dolphin acoustic activity during the
day of and day after the exercise within 3.7 mi (6 km). This held true
only during daytime, as nighttime activity did not appear different
than before the exercise, and two days after the explosion there seemed
to be an increase in daytime acoustic activity, indicating dolphins may
have returned to the area or resumed vocalizations (Lammers et al.,
2017). Weaver (2015) documented potential sex-based differences in
behavioral responses to impulsive noise during construction (including
blasting) of a bridge over a waterway commonly used by bottlenose
dolphins, where females decreased area use and males continued using
the area, perhaps indicating differential habitat uses.
When exposed to multiple impulses from a seismic air gun, Finneran
et al. (2015) noted some captive dolphins turned their heads away from
the source just before the impulse, indicating they could anticipate
the timing of the impulses and may be able to behaviorally mediate the
exposure to reduce their received level. Kavanagh et al. (2019) found
sightings of odontocete whales decreased by 53 percent during active
phases of seismic air gun surveys and 29 percent during inactive phases
compared to control surveys. Heide-Jorgensen et al. (2021) found that
narwhals exposed to air gun noise in an Arctic fjord were sensitive to
seismic vessels over 6.8 mi (11 km) away, even though the small air gun
source reached ambient noise levels around 1.9 mi (3 km) (source level
of 231 dB re 1 [mu]Pa at 1 m) and large air gun source reached ambient
noise levels around 6.2 mi (10 km) (source level 241 dB re 1 [mu]Pa at
1 m). Behavioral responses included changes in swimming speed and
swimming direction away from the impulsive sound source and towards the
shoreline. Changes in narwhal swimming speed was context-dependent and
usually increased in the presence of vessels but decreased (a
``freeze'' response) in response to closely approaching air gun pulses
(Heide-Jorgensen et al., 2021). A cessation of feeding was also
documented, when the impulsive noise was less than 6.2 mi (10 km) away,
although received SELs were less than 130 dB re 1 [mu]Pa\2\s for either
air gun at this distance. However, because of this study's research
methods and criteria, the long-distance responses of narwhals may be
conservatively estimating narwhals' range to behavioral response.
Similarly, harbor porpoises seem to have an avoidance response to
seismic surveys by leaving the area and decreasing foraging activity
within 3.1-6.2 mi (5-10 km) of the survey, as evidenced by both a
decrease in vocalizations near the survey and an increase in
vocalizations at a distance (Pirotta et al., 2014; Thompson et al.,
2013a). The response was short-term, as the porpoises returned to the
area within 1 day upon cessation of the air gun operation.
Sarnoci[nacute]ska et al. (2020) placed autonomous recording devices
near oil and gas platforms and control sites to measure harbor porpoise
acoustic activity during seismic air gun surveys. They noted a dose-
response effect, with the lowest amount of porpoise activity closest to
the seismic vessel (SELsingle shot = 155 dB re 1 [mu]Pa\2\s)
and increasing porpoise activity out to 5 to 7.5 mi (8 to 12 km), and
that distance to the seismic vessel, rather than sound level, was a
better model predictor of porpoise activity. Overall porpoise activity
in the seismic survey area was similar to the control sites
(approximately 9.3 mi (15 km) apart), which may indicate the harbor
porpoises were moving around the area to avoid the seismic vessel
without leaving the area entirely.
Pile driving, another activity that produces impulsive sound,
elicited a similar response in harbor porpoises. Benhemma-Le Gall et
al., 2021 examined changes in porpoise presence and foraging at two
offshore windfarms between control (102-104 dB) and construction
periods (155-161 dB), and found decreased presence (8-17 percent) and
decreased foraging activity (41-62 percent) during construction
periods. Porpoises were displaced up to 7.5 mi (12 km) away from pile
driving and 2.5 mi (4 km) from construction vessels. Multiple studies
have documented strong avoidance responses by harbor porpoises out to
12.4 mi (20 km) during pile driving activity, however, animals returned
to the area after the activity stopped (Brandt et al., 2011; D[auml]hne
et al., 2014; Haelters et al., 2014; Thompson et al., 2010; Tougaard et
al., 2005; Tougaard et al., 2009). When bubble curtains were deployed
around pile driving, the avoidance distance appeared to be reduced by
half

[[Page 19924]]

to 7.5 mi (12 km), and the animals returned to the area after
approximately 5 hours rather than 1 day later (D[auml]hne et al.,
2017). Further, Bergstr[ouml]m et al. (2014) found that although there
was a high likelihood of acoustic disturbance during wind farm
construction (including pile driving), the impact was short-term, and
Graham et al. (2019) found that the distance at which behavioral
responses of harbor porpoises were likely decreased over the course of
a construction project, suggesting habituation to impulsive pile-
driving noise. Kastelein et al. (2013b) exposed captive harbor
porpoises to impact pile driving noise, and found that respiration
rates increased above 136 dB re 1 [micro]Pa (zero-to-peak), and at
higher sound levels individuals jumped more frequently. When a single
harbor porpoise was exposed to playbacks of impact pile driving noise
with different bandwidths, Kastelein et al. (2022) found the animal's
behavioral response (i.e., swim speed, respiration rate, jumping)
decreased with bandwidth.
Overall, odontocete behavioral responses to impulsive sound sources
are likely species- and context-dependent. Responses might be expected
close to a noise source, under specific behavioral conditions such as
females with offspring, or for sensitive species such as harbor
porpoises, while many other species demonstrate little to no behavioral
response.
Pinnipeds seem to be the least sensitive marine mammal group to
impulsive noise (Richardson et al., 1995b; Southall et al., 2007), and
some may even experience hearing effects before exhibiting a behavioral
response (Southall et al., 2007). Some species may be more sensitive
and are only likely to respond (e.g., startling, entering the water,
ceasing foraging) to loud impulsive noises in close proximity, but only
for brief periods of time before returning to their previous behavior.
Demarchi et al. (2012) exposed Steller sea lions to in-air explosive
blasts, which resulted in increased activity levels and often caused
re-entry into the water from a hauled out state. These responses were
brief (lasting only minutes) and the animals returned to haul outs and
there were no documented lasting behavioral impacts in the days
following the explosions.
Ringed seals exhibited little or no response to pile driving noise
with mean underwater levels of 157 dB re 1 [mu]Pa and in-air levels of
112 dB re 20 [mu]Pa (Blackwell et al., 2004) while harbor seals vacated
the area surrounding an active pile driving site at estimated received
levels between 166-178 dB re 1 [mu]Pa SPL (peak to peak), returning
within 2 hours of the completion of piling activities (Russell et al.,
2016). Wild-captured gray seals exposed to a startling treatment (sound
with a rapid rise time and a 93 dB sensation level (the level above the
animal's hearing threshold at that frequency) avoided a known food
source, whereas animals exposed to a non-startling treatment (sound
with a slower rise time but peaking at the same level) did not react or
habituated during the exposure period (G[ouml]tz and Janik, 2011).
These results underscore the importance of the characteristics of an
acoustic signal in predicting an animal's response of habituation.
Hastie et al. (2021) studied how the number and severity of
avoidance events may be an outcome of marine mammal cognition and risk
assessment using captive grey seals. Five individuals were given the
option to forage in a high- or low-density prey patch while
continuously exposed to silence or anthropogenic noise (pile driving or
tidal turbine operation) playbacks (148 dB re 1 [mu]Pa at 1 m). For
each trial, one prey patch was closer to the source, therefore having a
higher received level in experimental exposures than the other prey
patch. The authors found that foraging success was highest during
silent periods and that the seals avoided both anthropogenic noises
with higher received levels when the prey density was limited (low-
density prey patch). The authors concluded the seals made foraging
decisions within the trials based on both the energetic value of the
prey patch (low-density corresponding to low energetic value, high-
density corresponding to high energetic value), and the nature and
location of the acoustic signal relative to the prey patches of
different value.
Responses Due to Vessel Noise--
Mysticetes have varied responses to vessel noise and presence, from
having no response to approaching vessels to exhibiting an avoidance
response by both horizontal (swimming away) and vertical (increased
diving) movement (Baker et al., 1983; Fiori et al., 2019; Gende et al.,
2011; Watkins, 1981). Avoidance responses include changing swim
patterns, speed, or direction (Jahoda et al., 2003), remaining
submerged for longer periods of time (Au & Green, 2000), and performing
shallower dives with more frequent surfacing. Behavioral responses to
vessels range from smaller-scale changes, such as altered breathing
patterns (e.g., Baker et al., 1983; Jahoda et al., 2003), to larger-
scale changes such as a decrease in apparent presence (Anderwald et
al., 2013). Other common behavioral responses include changes in
vocalizations, surface time, feeding and social behaviors (Au & Green,
2000; Dunlop, 2019; Fournet et al., 2018; Machernis et al., 2018;
Richter et al., 2003; Williams et al., 2002a). For example, NARWs have
been reported to increase the amplitude or frequency of their
vocalizations or call at a lower rate in the presence of increased
vessel noise (Parks et al., 2007; Parks et al., 2011), but generally
demonstrate little to no response to vessels or sounds from approaching
vessels and often continue to use habitats in high vessel traffic areas
(Nowacek et al. 2004a). This lack of response may be due to habituation
to the presence and associated noise of vessels in NARW habitat or may
be due to propagation effects that may attenuate vessel noise near the
surface (Nowacek et al., 2004a; Terhune & Verboom, 1999).
Similarly, sei whales have been observed ignoring the presence of
vessels entirely and even pass close to vessels (Reeves et al., 1998).
Historically, fin whales tend to ignore vessels at a distance (Watkins,
1981) or habituate to vessels over time (Watkins, 1986) but still
demonstrate vocal modifications (e.g., decreased frequency parameters
of calls) during vessel traffic. Ramesh et al. (2021) found that fin
whale calls in Ireland were less likely to be detected for every 1 dB
re 1 [mu]Pa/minute increase in shipping noise levels. In the presence
of tour boats in Chile, fin whales were changing their direction of
movement more frequently, with less linear movement than occurred
before the boats arrived; this behavior may represent evasion or
avoidance of the boats (Santos-Carvallo et al., 2021). The increase in
travel swim speeds after the vessels departed may be related to the
rapid speeds at which the vessels traveled, sometimes in front of fin
whales, leading to additional avoidance behavior post-exposure.
Mysticete behavioral responses to vessels may also be affected by
vessel behavior (Di Clemente et al., 2018; Fiori et al., 2019).
Avoidance responses occurred most often after ``J'' type vessel
approaches (i.e., traveling parallel to the whales' direction of
travel, then overtaking the whales by turning in front of the group)
compared to parallel or direct approaches. Mother humpbacks were
particularly sensitive to direct and J type approaches and spent
significantly more time diving in response (Fiori et al., 2019). The
presence of a passing vessel did not change the behavior of resting
humpback whale mother-calf pairs, but

[[Page 19925]]

fast vessels with louder low-frequency weighted source levels (173 dB
re 1 [mu]Pa, equating to weighted received levels of 133 dB re 1
[mu]Pa) at an average distance of 328 ft (100 m) resulted in a
decreased resting behavior and increases in dives, swim speeds, and
respiration rates (Sprogis et al., 2020). Humpback whale responses to
vessel disturbance were dependent on their behavioral state. Di
Clemente et al. (2018) found that when vessels passed within 1,640 ft
(500 m) of humpback whales, individuals would continue to feed if
already engaged in feeding behavior but were more likely to start
swimming if they were surface active when approached. In response to an
approaching large commercial vessel in an area of high ambient noise
levels (125-130 dB re 1 [mu]Pa), a tagged female blue whale turned
around mid-ascent and descended perpendicular to the vessel's path
(Szesciorka et al., 2019). The whale did not respond until the vessel's
closest point of approach (328 ft (100 m) distance, 135 dB re 1
[mu]Pa), which was 10 dB above the ambient noise levels. After the
vessel passed, the whale ascended to the surface again with a three-
minute delay.
Overall, mysticete responses to vessel noise and traffic are
varied, and habituation or changes to vocalization are predominant
long-term responses. When baleen whales do avoid vessels, they seem to
do so by altering their swim and dive patterns to move away from the
vessel. Although a lack of response in the presence of a vessel may
minimize potential disturbance from passing vessels, it does increase
the whales' vulnerability to vessel strike, which may be of greater
concern for mysticetes than vessel noise.
Odontocete responses due to vessel noise are varied and context-
dependent, and it is difficult to separate the impacts of vessel noise
from the impacts of vessel presence. Vessel presence has been shown to
interrupt feeding behavior in delphinids in some studies (Meissner et
al., 2015; Pirotta et al., 2015b) while a recent study by Mills et al.
(2023) found that, in an important foraging area, bottlenose dolphins
may continue to forage and socialize even while constantly exposed to
high vessel traffic. Ng and Leung (2003) found that the type of vessel,
approach, and speed of approach can all affect the probability of a
negative behavioral response and, similarly, Guerra et al. (2014)
documented varied responses in group structure and vocal behavior.
While most odontocetes have documented neutral responses to
vessels, avoidance (Bejder et al., 2006a; W[uuml]rsig et al., 1998) and
attraction (Norris & Prescott, 1961; Ritter, 2002; Shane et al., 1986;
Westdal et al., 2023; W[uuml]rsig et al., 1998) behaviors have also
been observed (Hewitt, 1985). Archer et al. (2010) compared the
responses of dolphin populations far offshore that were often targeted
by tuna fisheries to populations closer (less than 100 nmi (185.2 km))
to shore and found the fisheries-associated populations (spotted,
spinner, and common dolphins) showed evasive behavior when approached
by vessels while those nearshore species not associated with offshore
fisheries (coastal spotted and bottlenose dolphins) tended to be
attracted to vessels.
Arranz et al. (2021) used different engine types to determine
whether behavioral responses of short-finned pilot whales were
attributable to vessel noise, vessel presence, or both. Mother-calf
pairs were approached by the same vessel outfitted with either
``quiet'' electric engines or ``noisy'' traditional combustion engines,
controlling for approach speed and distance. Arranz et al. (2021) found
mother pilot whales rested less and calves nursed less in response to
both types of engines compared to control conditions, but only the
``noisy'' engine caused significant impacts (29 percent and 81 percent,
respectively).
Smaller vessels tend to generate more noise in higher frequency
bands, are more likely to approach odontocetes directly, and spend more
time near an animal. Carrera et al. (2008) found tour boat activity can
cause short-term displacement of dolphins, and Haviland-Howell et al.
(2007) documented longer term or repetitive displacement of dolphins
due to chronic vessel noise. Delphinid behavioral states also change in
the presence of small tour vessels that often approach animals: travel
and resting increases, foraging and social behavior decreases, and
animals move closer together (Cecchetti et al., 2017; Clarkson et al.,
2020; Kassamali-Fox et al., 2020; Meissner et al., 2015). Most studies
on behavioral responses of bottlenose dolphin to vessel traffic show at
least short-term changes in behavior, activities, or vocalization
patterns when vessels are nearby (Acevedo, 1991; Arcangeli & Crosti,
2009; Berrow & Holmes, 1999; Fumagalli et al., 2018; Gregory & Rowden,
2001; Janik & Thompson, 1996; Lusseau, 2004; Marega et al., 2018;
Mattson et al., 2005; Perez-Ortega et al., 2021; Puszka et al., 2021;
Scarpaci et al., 2000).
Information is limited on beaked whale responses to vessel noise,
but W[uuml]rsig et al. (1998) noted that most beaked whales seem to
exhibit avoidance behaviors when exposed to vessels and beaked whales
may respond to all anthropogenic noise (i.e., sonar, vessel) at similar
sound levels (Aguilar de Soto et al., 2006; Tyack et al., 2011; Tyack,
2009). The information available includes a disruption of foraging by a
vocalizing goose-beaked whale in the presence of a passing vessel
(Aguilar de Soto et al., 2006) and restriction of group movement, or
possibly reduction in the number of individuals clicking within the
group, after exposure to broadband (received level of 135 dB re 1
[mu]Pa) vessel noise up to at least 3.2 mi (5.2 km) away from the
source, though no change in duration of Blainville's beaked whale
foraging dives was observed (Pirotta et al., 2012).
Porpoises and small delphinids are known to be sensitive to vessel
noise, as well. Frankish et al. (2023) found harbor porpoises more
likely to avoid large commercial vessels via horizontal movement during
the day and vertical movement at night, which supports previous
research that the species routinely avoids large motorized vessels
(Polacheck and Thorpe, 1990). Harbor porpoises have also been
documented responding to vessels with increased changes in behavioral
state and significantly decreased feeding (Akkaya Bas et al., 2017),
fewer clicks (Sairanen, 2014), and fewer prey capture attempts and have
disrupted foraging when vessels pass closely and noise levels are
higher (Wisniewska et al., 2018). Habituation to vessel noise and
presence was observed for a resident population of harbor porpoises
that was in regular proximity to vessel traffic (32.8 ft to 0.6 mi (10
m to 1 km) away); the population had no response in 74 percent of
interactions and an avoidance response in 26 percent of interactions.
It should be noted that fewer responses in populations of odontocetes
regularly subjected to high levels of vessel traffic could be a sign of
habituation, or it could be that the more sensitive individuals in the
population have abandoned that area of higher human activity. Most
avoidance responses were the result of fast-moving or steady plane-
hulling motorized vessels and the vessel type and speed were considered
to be more relevant than vessel presence, as few responses were
observed to non-motorized or stationary vessels (Oakley et al., 2017).
Similarly, Akkaya Bas et al. (2017) found that when fast moving vessels
were within 164 ft (50 m) of harbor porpoises, there was an 80 percent
probability of change in swimming direction but only a 40 percent
probability of change when vessels were beyond 1,312.3 ft (400 m).
Frankish et al. (2023) found that harbor

[[Page 19926]]

porpoises were most likely to avoid vessels less than 984.3 ft (300 m)
away but, 5-10 percent of the time, they would also respond to vessels
more than 1.2 mi (2 km) away, signifying that were not just attuning to
vessel presence but vessel noise, as well. Although most vessel noise
is constrained to frequencies below 1 kHz, at close ranges vessel noise
can extend into mid- and high frequencies (into the tens of kHz)
(Hermannsen et al., 2014; Li et al., 2015) and it is these frequencies
that harbor porpoises are likely responding to; the mean M-weighted
received SPL threshold for a response at these frequencies is 123 dB re
1 [mu]Pa (Dyndo et al., 2015). M-weighting functions are generalized
frequency weightings for various groups of marine mammals that were
defined by Southall et al. (2007) based on known or estimated auditory
sensitivity at different frequencies, and are used to characterize
auditory effects of strong sounds. Hermannsen et al. (2019) estimated
that noise in the 16 kHz frequency band resulting from small
recreational vessels could cause behavioral directions in harbor
porpoises, and could be elevated up to 124 dB re 1 [mu]Pa and raise
ambient noise levels by a maximum of 51 dB. The higher noise levels
were associated with vessel speed and range, which exceeded the
threshold levels found by Dyndo et al. (2015) and Wisniewska et al.
(2018) by 49-85 percent of events with high levels of vessel noise.
Lusseau and Bejder (2007) have reported some long-term consequences
of vessel noise on odontocetes but, overall, there is little
information on the long-term and cumulative impacts of vessel noise
(National Academies of Sciences Engineering and Medicine, 2017;
National Marine Fisheries Service, 2007). Many researchers speculate
that long-term impacts may occur on odontocete populations that
experience repeated interruption of foraging behaviors (Stockin et al.,
2008), and Southall et al. (2021) indicates that, in many contexts, the
localized and coastal home ranges typical of many species make them
less resilient to this chronic stressor than mysticetes.
Context and experience likely play a role in pinnipeds response to
vessel noise, which vary from negative responses including increased
vigilance and alerting to avoidance to reduced time spent doing
biologically important activities (e.g., resting, feeding, and nursing)
(Martin et al., 2023a; Martin et al., 2022; Mikkelsen et al., 2019;
Richardson et al., 1995b) to attraction or lack of observable response
(Richardson et al., 1995b). More severe responses, like flushing, could
be more detrimental to individuals during biologically important
activities and times, such as during pupping season. Blundell and
Pendleton (2015) found that vessel presence reduces haul out time of
Alaskan harbor seals during pupping season and larger vessels elicit
stronger responses. Cates and Acevedo-Guti[eacute]rrez (2017) modeled
harbor seal responses to passing vessels at haul out sites in less
trafficked areas and found the model best predicting flushing behavior
included number of boats, type of boats, and distance of seals to
boats. The authors noted flushing occurred more in response to non-
motorized vessels (e.g., kayaks), likely because they tended to pass
closer (82 to 603.7 ft (25 to 184 m)) to haul out sites than motorized
vessels (180.4 to 1,939 ft (55 to 591 m)) and tended to occur in groups
rather than as a single vessel. Cape fur seals were also more
responsive to vessel noise at sites with a large breeding colony than
at sites with lower abundances of conspecifics (Martin et al., 2023a).
A field study of harbor and gray seals showed that seal responses to
vessels included interruption of resting and foraging during times when
vessel noise was increasing or at its peak (Mikkelsen et al., 2019).
And, although no behavioral differences were observed in hauled out
wild cape fur seals exposed to low (60-64 dB re 20 [mu]Pa RMS SPL),
medium (64-70 dB) and high-level (70-80 dB) vessel noise playbacks,
mother-pup pairs spent less time nursing (15-31 percent) and more time
awake (13-26 percent), vigilant (7-31 percent), and mobile (2-4
percent) during vessel noise conditions compared to control conditions
(Martin et al., 2022).
Masking
Sound can disrupt behavior through masking, or interfering with, an
animal's ability to detect, recognize, interpret, or discriminate
between acoustic signals of interest (e.g., those used for
intraspecific communication and social interactions, prey detection,
predator avoidance, or navigation) (Clark et al., 2009; Richardson et
al., 1995; Erbe and Farmer, 2000; Tyack, 2000; Erbe et al., 2016;
Branstetter and Sills, 2022). Masking occurs when the receipt of a
sound is interfered with by another coincident sound at similar
frequencies and at similar or higher intensity and may occur whether
the coincident sound is natural (e.g., snapping shrimp, wind, waves,
precipitation) or anthropogenic (e.g., shipping, sonar, seismic
exploration) in origin. As described in detail in appendix D, section
D.6.4 (Masking), of the 2024 AFTT Draft Supplemental EIS/OEIS, the
ability of a noise source to mask biologically important sounds depends
on the characteristics of both the noise source and the signal of
interest (e.g., signal-to-noise ratio, temporal variability,
direction), in relation to each other and to an animal's hearing
abilities (e.g., sensitivity, frequency range, critical ratios,
frequency discrimination, directional discrimination, age, or TTS
hearing loss), and existing ambient noise and propagation conditions.
Masking these acoustic signals can disturb the behavior of individual
animals, groups of animals, or entire populations. Masking can lead to
behavioral changes including vocal changes (e.g., Lombard effect,
increasing amplitude, or changing frequency), cessation of foraging,
and leaving an area, to both signalers and receivers, in an attempt to
compensate for noise levels (Erbe et al., 2016).
Most research on auditory masking is focused on energetic masking,
or the ability of the receiver (i.e., listener) to detect a signal in
noise. However, from a fitness perspective, both signal detection and
signal interpretation are necessary for success. This type of masking
is called informational masking and occurs when a signal is detected by
an animal but the meaning of that signal has been lost. Few data exist
on informational masking in marine mammals but studies have shown that
some recognition of predator cues might be missed by species that are
preyed upon by killer whales if killer whale vocalizations are masked
(Cur[eacute] et al., 2016; Cur[eacute] et al., 2015; Deecke et al.,
2002; Isojunno et al., 2016; Visser et al., 2016). von Benda-Beckman et
al. (2021) modeled the effect of pulsed and continuous active sonars
(CAS) on sperm whale echolocation and found that sonar sounds could
reduce the ability of sperm whales to find prey under certain
conditions.
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is man-made, it may be considered harassment
when disrupting natural behavioral patterns to the point where the
behavior is abandoned or significantly altered. It is important to
distinguish TTS and PTS, which persist after the sound exposure, from
masking, which only occurs during the sound exposure. Because masking
(without resulting in threshold shift) is not associated with abnormal
physiological function, it is not considered a physiological effect,
but rather a potential behavioral effect.

[[Page 19927]]

Richardson et al. (1995) argued that the maximum radius of
influence of an industrial noise (including broadband low-frequency
sound transmission) on a marine mammal is the distance from the source
to the point at which the noise can barely be heard. This range is
determined by either the hearing sensitivity (including critical
ratios, or the lowest signal-to-noise ratio in which animals can detect
a signal) of the animal (Finneran and Branstetter, 2013; Johnson et
al., 1989; Southall et al., 2000) or the background noise level
present. Industrial masking is most likely to affect some species'
ability to detect communication calls and natural sounds (i.e., surf
noise, prey noise, etc.) (Richardson et al., 1995).
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009; Matthews et al., 2016) and may result in energetic
or other costs as animals change their vocalization behavior (e.g.,
Miller et al., 2000; Foote et al., 2004; Parks et al., 2007; Di Iorio
and Clark, 2009; Holt et al., 2009). Masking can be reduced in
situations where the signal and noise come from different directions
(Richardson et al., 1995), through amplitude modulation of the signal,
or through other compensatory behaviors (Houser and Moore, 2014).
Masking can be tested directly in captive species, but in wild
populations it must be either modeled or inferred from evidence of
masking compensation. There are few studies addressing real-world
masking sounds likely to be experienced by marine mammals in the wild
(e.g., Cholewiak et al., 2018; Branstetter and Sills, 2023; Branstetter
et al., 2024).
High-frequency sounds may mask the echolocation calls of toothed
whales. Human data indicate low-frequency sound can mask high-frequency
sounds (i.e., upward masking). Studies on captive odontocetes by Au et
al. (1974, 1985, 1993) indicate that some species may use various
processes to reduce masking effects (e.g., adjustments in echolocation
call intensity or frequency as a function of background noise
conditions). There is also evidence that the directional hearing
abilities of odontocetes are useful in reducing masking at the high-
frequencies these cetaceans use to echolocate, but not at the low-to-
moderate frequencies they use to communicate (Zaitseva et al., 1980). A
study by Nachtigall and Supin (2018) showed that false killer whales
adjust their hearing to compensate for ambient sounds and the intensity
of returning echolocation signals.
Impacts on signal detection, measured by masked detection
thresholds, are not the only important factors to address when
considering the potential effects of masking. As marine mammals use
sound to recognize conspecifics, prey, predators, or other biologically
significant sources (Branstetter et al., 2016), it is also important to
understand the impacts of masked recognition thresholds (informational
masking). Branstetter et al. (2016) measured masked recognition
thresholds for whistle-like sounds of bottlenose dolphins and observed
that they are approximately 4 dB above detection thresholds (energetic
masking) for the same signals. Reduced ability to recognize a
conspecific call or the acoustic signature of a predator could have
severe negative impacts. Branstetter et al. (2016) observed that if
``quality communication'' is set at 90 percent recognition the output
of communication space models (which are based on 50 percent detection)
would likely result in a significant decrease in communication range.
As marine mammals use sound to recognize predators (Allen et al.,
2014; Cummings and Thompson, 1971; Cure, et al., 2015; Fish and Vania,
1971), the presence of masking noise may also prevent marine mammals
from responding to acoustic cues produced by their predators,
particularly if it occurs in the same frequency band. For example,
harbor seals that reside in the coastal waters of British Columbia are
frequently targeted by mammal-eating killer whales. The seals
acoustically discriminate between the calls of mammal-eating and fish-
eating killer whales (Deecke et al., 2002), a capability that should
increase survivorship while reducing the energy required to identify
all killer whale calls. Similarly, sperm whales (Cure, et al., 2016;
Isojunno et al., 2016), long-finned pilot whales (Visser et al., 2016),
and humpback whales (Cure, et al., 2015) changed their behavior in
response to killer whale vocalization playbacks. The potential effects
of masked predator acoustic cues depends on the duration of the masking
noise and the likelihood of a marine mammal encountering a predator
during the time that detection and recognition of predator cues are
impeded.
Redundancy and context can also facilitate detection of weak
signals. These phenomena may help marine mammals detect weak sounds in
the presence of natural or anthropogenic noise. Most masking studies in
marine mammals present the test signal and the masking noise from the
same direction. The dominant background noise may be highly directional
if it comes from a particular anthropogenic source such as a vessel or
industrial site. Directional hearing may significantly reduce the
masking effects of these sounds by improving the effective signal-to-
noise ratio.
Masking affects both senders and receivers of acoustic signals and
can potentially have long-term chronic effects on marine mammals at the
population level as well as at the individual level. Low-frequency
ambient sound levels have increased by as much as 20 dB (more than
three times in terms of SPL) in the world's ocean from pre-industrial
periods, with most of the increase from distant commercial shipping
(Hildebrand, 2009; Cholewiak et al., 2018). All anthropogenic sound
sources, but especially chronic and lower-frequency signals (e.g., from
commercial vessel traffic), contribute to elevated ambient sound
levels, thus intensifying masking for marine mammals.
Masking Due to Sonar and Other Transducers--
The functional hearing ranges of mysticetes, odontocetes, and
pinnipeds underwater overlap the frequencies of the sonar sources used
in the Action Proponents' LFAS/MFAS/high-frequency active sonar (HFAS)
training and the Navy's testing exercises. Additionally, almost all
affected species' vocal repertoires span across the frequencies of
these sonar sources used by the Action Proponents. The closer the
characteristics of the masking signal to the signal of interest, the
more likely masking is to occur. Masking by LFAS or MFAS with
relatively low-duty cycles is not anticipated (or would be of very
short duration) for most cetaceans as sonar signals occur over a
relatively short duration and narrow bandwidth (overlapping with only a
small portion of the hearing range). LFAS could overlap in frequency
with mysticete vocalizations, however LFAS does not overlap with
vocalizations for most marine mammal species. For example, in the
presence of LFAS, humpback whales were observed to increase the length
of their songs (Fristrup et al., 2003; Miller et al., 2000),
potentially

[[Page 19928]]

due to the overlap in frequencies between the whale song and the LFAS.
While dolphin whistles and MFAS are similar in frequency, masking is
not anticipated (or would be of very short duration) due to the low-
duty cycle and short durations of most sonars.
As described in additional detail in the 2024 AFTT Draft
Supplemental EIS/OEIS, high duty-cycle or CAS have more potential to
mask vocalizations. These sonars transmit more frequently (greater than
80 percent duty cycle) than traditional sonars, but typically at lower
source levels. HFAS, such as pingers that operate at higher repetition
rates, also operate at lower source levels and have faster attenuation
rates due to the higher frequencies used. These lower source levels
limit the range of impacts, however, compared to traditional sonar
systems, individuals close to the source are likely to experience
masking at longer time scales. The frequency range at which high-duty
cycle systems operate overlaps the vocalization frequency of many mid-
frequency cetaceans. Continuous noise at the same frequency of
communicative vocalizations may cause disruptions to communication,
social interactions, and acoustically mediated cooperative behaviors
(S[oslash]rensen et al., 2023) such as foraging and mating. Similarly,
because the high-duty cycle or CAS includes mid-frequency sources,
there is also the potential for the mid-frequency sonar signals to mask
important environmental cues (e.g., predator or conspecific acoustic
cues), possibly affecting survivorship for targeted animals. Spatial
release from masking may occur with higher duty cycle or CAS.
While there are currently few studies of the impacts of high-duty
cycle sonars on marine mammals, masking due to these systems is likely
analogous to masking produced by other continuous sources (e.g., vessel
noise and low-frequency cetaceans), and would likely have similar
short-term consequences, though longer in duration due to the duration
of the masking noise. These may include changes to vocalization
amplitude and frequency (Brumm and Slabbekoorn, 2005; Hotchkin and
Parks, 2013) and behavioral impacts such as avoidance of the area and
interruptions to foraging or other essential behaviors (Gordon et al.,
2003). Long-term consequences could include changes to vocal behavior
and vocalization structure (Foote et al., 2004; Parks et al., 2007),
abandonment of habitat if masking occurs frequently enough to
significantly impair communication (Brumm and Slabbekoorn, 2005), a
potential decrease in survivorship if predator vocalizations are masked
(Brumm and Slabbekoorn, 2005), and a potential decrease in recruitment
if masking interferes with reproductive activities or mother-calf
communication (Gordon et al., 2003).
von Benda-Beckmann et al. (2021) modeled the effect of pulsed and
continuous 1 to 2 kHz active sonar on sperm whale echolocation clicks
and found that the presence of upper harmonics in the sonar signal
increased masking of clicks produced in the search phase of foraging
compared to buzz clicks produced during prey capture. Different levels
of sonar caused intermittent to continuous masking (120 to 160 dB re 1
[micro]Pa\2\, respectively), but varied based on click level, whale
orientation, and prey target strength. CAS resulted in a greater
percentage of time that echolocation clicks were masked compared to
pulsed active sonar. This means that sonar sounds could reduce the
ability of sperm whales to find prey under certain conditions. However,
echoes from prey are most likely spatially separated from the sonar
source, and so spatial release from masking would be expected.
Masking Due to Impulsive Noise--
Impulsive sound sources, including explosions, are intense and
short in duration. Since impulsive noise is intermittent, the length of
the gap between sounds (duty-cycle) and received level are relevant
when considering the potential for masking. Impulsive sounds with lower
duty cycles or lower received levels are less likely to result in
masking than higher duty cycles or received levels. There are no direct
observations of masking in marine mammals due to exposure to explosive
sources. Potential masking from explosive sounds or weapon noise is
likely similar to masking studied for other impulsive sounds, such as
air guns or pile-driving.
Masking of mysticete calls could occur due to the overlap between
their low-frequency vocalizations and the dominant frequencies of
impulsive sources (Castellote et al., 2012; Nieukirk et al., 2012). For
example, blue whale feeding/social calls increased when seismic
exploration was underway (Di Lorio & Clark, 2010), indicative of a
possible compensatory response to masking effects of the increased
noise level. However, mysticetes that call at higher rates are less
likely to be masked by impulsive noise with lower duty cycles (Clark et
al., 2009) because of the decreased likelihood that the noise would
overlap with the calls, and because of dip listening. Field
observations of masking effects such as vocal modifications are
difficult to interpret because when recordings indicate that call rates
decline, this could be caused by (1) animals calling less frequently
(actual noise-induced vocal modifications), (2) the calls being masked
from the recording hydrophone due to the noise (e.g., animals are not
calling less frequently but are being detected less frequently), or (3)
the animals moving away from the noise, or any combination of these
causes (Blackwell et al., 2013; Cerchio et al., 2014).
Masking of pinniped communication sounds at 100 Hz center frequency
is possible when vocalizations occur at the same time as an air gun
pulse (Sills et al., 2017). This might result in some percentage of
vocalizations being masked if an activity such as a seismic survey is
being conducted in the vicinity, even when the sender and receiver are
near one another. Release from masking due to ``dip listening'' is
likely in this scenario.
While a masking effect of impulsive noise can depend on the
received level (Blackwell et al., 2015) and other characteristics of
the noise, the vocal response of the affected animal to masking noise
is an equally important consideration for inferring overall impacts to
an animal. It is possible that the receiver would increase the rate
and/or level of calls to compensate for masking; or, conversely, cease
calling.
In general, impulsive noise has the potential to mask sounds that
are biologically important for marine mammals, reducing communication
space or resulting in noise-induced vocal modifications that might
impact marine mammals. Masking by close-range impulsive sound sources
is most likely to impact marine mammal communication.
Masking Due to Vessel Noise--
Masking is more likely to occur in the presence of broadband,
relatively continuous noise sources such as vessels. Several studies
have shown decreases in marine mammal communication space and changes
in behavior as a result of the presence of vessel noise. For example,
NARW were observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007) as well as increasing the amplitude
(intensity) of their calls (Parks, 2009; Parks et al., 2011). Fournet
et al. (2018) observed that humpback whales in Alaska responded to
increasing ambient sound levels (natural and anthropogenic) by
increasing the source levels of their calls (non-song

[[Page 19929]]

vocalizations). Clark et al. (2009) also observed that right whales
communication space decreased by up to 84 percent in the presence of
vessels (Clark et al., 2009). Cholewiak et al. (2018) also observed
loss in communication space in Stellwagen National Marine Sanctuary for
NARW, fin whales, and humpback whales with increased ambient noise and
shipping noise. Gabriele et al. (2018) modeled the effects of vessel
traffic sound on communication space in Glacier Bay National Park in
Alaska and found that typical summer vessel traffic in the Park causes
losses of communication space to singing whales (reduced by 13-28
percent), calling whales (18-51 percent), and roaring seals (32-61
percent), particularly during daylight hours and even in the absence of
cruise ships. Dunlop (2019) observed that an increase in vessel noise
reduced modeled communication space and resulted in significant
reduction in group social interactions in Australian humpback whales.
However, communication signal masking did not fully explain this change
in social behavior in the model, indicating there may also be an
additional effect of the physical presence of the vessel on social
behavior (Dunlop, 2019). Although humpback whales off Australia did not
change the frequency or duration of their vocalizations in the presence
of ship noise, their source levels were lower than expected based on
source level changes to wind noise, potentially indicating some signal
masking (Dunlop, 2016). Multiple delphinid species have also been shown
to increase the minimum or maximum frequencies of their whistles in the
presence of anthropogenic noise and reduced communication space (e.g.,
Holt et al., 2009; Holt et al., 2011; Gervaise et al., 2012; Williams
et al., 2013; Hermannsen et al., 2014; Papale et al., 2015; Liu et al.,
2017).
Other Physiological Response
Physiological stress is a natural and adaptive process that helps
an animal survive changing conditions. When an animal perceives a
potential threat, whether or not the stimulus actually poses a threat,
a stress response is triggered (Seyle, 1950; Moberg, 2000; Sapolsky et
al., 2005). Once an animal's central nervous system perceives a threat,
it mounts a biological response or defense that consists of a
combination of behavioral responses, autonomic nervous system
responses, neuroendocrine responses, or immune responses.
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and distress is the biotic cost
of the response. During a stress response, an animal uses glycogen
stores that can be quickly replenished once the stress is alleviated.
In such circumstances, the cost of the stress response would not pose
serious fitness consequences. However, when an animal does not have
sufficient energy reserves to satisfy the energetic costs of a stress
response, energy resources must be diverted from other biotic
functions. For example, when a stress response diverts energy away from
growth in young animals, those animals may experience stunted growth.
When a stress response diverts energy from a fetus, an animal's
reproductive success and its fitness will suffer. In these cases, the
animals will have entered a pre-pathological or pathological state
which is called ``distress'' (Seyle, 1950) or ``allostatic loading''
(McEwen and Wingfield, 2003). This pathological state of distress will
last until the animal replenishes its energetic reserves sufficiently
to restore normal function.
According to Moberg (2000), in the case of many stressors, an
animal's first and sometimes most economical (in terms of biotic costs)
response is behavioral avoidance of the potential stressor or avoidance
of continued exposure to a stressor. An animal's second line of defense
to stressors involves the sympathetic part of the autonomic nervous
system and the classical ``fight or flight'' response which includes
the cardiovascular system, the gastrointestinal system, the exocrine
glands, and the adrenal medulla to produce changes in heart rate, blood
pressure, and gastrointestinal activity that humans commonly associate
with ``stress.'' These responses have a relatively short duration and
may or may not have significant long-term effect on an animal's
welfare.
An animal's third line of defense to stressors involves its
neuroendocrine systems or sympathetic nervous systems; the system that
has received the most study has been the hypothalamus-pituitary-adrenal
system (also known as the HPA axis in mammals or the hypothalamus-
pituitary-interrenal axis in fish and some reptiles). Unlike stress
responses associated with the autonomic nervous system, virtually all
neuro-endocrine functions that are affected by stress, including immune
competence, reproduction, metabolism, and behavior, are regulated by
pituitary hormones. Stress-induced changes in the secretion of
pituitary hormones have been implicated in failed reproduction (Moberg,
1987; Rivier and Rivest, 1991), altered metabolism (Elasser et al.,
2000), reduced immune competence (Blecha, 2000), and behavioral
disturbance (Moberg, 1987; Blecha, 2000). Increases in the circulation
of glucocorticosteroids (cortisol, corticosterone, and aldosterone in
marine mammals; see Romano et al., 2004) have been equated with stress
for many years.
Marine mammals naturally experience stressors within their
environment and as part of their life histories. Changing weather and
ocean conditions, exposure to disease and naturally occurring toxins,
lack of prey availability, and interactions with predators all
contribute to the stress a marine mammal experiences (Atkinson et al.,
2015). Breeding cycles, periods of fasting, social interactions with
members of the same species, and molting (for pinnipeds) are also
stressors, although they are natural components of an animal's life
history. Anthropogenic activities have the potential to provide
additional stressors beyond those that occur naturally (e.g., fishery
interactions, pollution, tourism, ocean noise) (Fair et al., 2014;
Meissner et al., 2015; Rolland et al., 2012).
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005; Reneerkens et al., 2002;
Thompson and Hamer, 2000). However, it should be noted (and as is
described in additional detail in the 2024 AFTT Draft Supplemental EIS/
OEIS) that our understanding of the functions of various stress
hormones (e.g., cortisol), is based largely upon observations of the
stress response in terrestrial mammals. Atkinson et al., (2015) note
that the endocrine response of marine mammals to stress may not be the
same as that of terrestrial mammals because of the selective pressures
marine mammals faced during their evolution in an ocean environment.
For example, due to the necessity of breath-holding while diving and
foraging at depth, the physiological role of epinephrine and
norepinephrine (the catecholamines) in marine mammals might be
different than in other mammals. Relatively little information exists
on the linkage between anthropogenic sound exposure and stress in
marine mammals, and even less information exists on the ultimate
consequences of sound-induced stress responses (either acute or
chronic). Most studies to date have focused on acute responses to sound

[[Page 19930]]

either by measuring neurohormones (i.e., catecholamines) or heart rate
as a proxy for an acute stress response.
The ability to make predictions from stress hormones about impacts
on individuals and populations exposed to various forms of natural and
anthropogenic stressors relies on understanding the linkages between
changes in stress hormones and resulting physiological impacts.
Currently, the sound characteristics that correlate with specific
stress responses in marine mammals are poorly understood, as are the
ultimate consequences of these changes. Several research efforts have
improved the understanding of, and the ability to predict, how
stressors ultimately affect marine mammal populations (e.g., King et
al., 2015; New et al., 2013a; Pirotta et al., 2015a; Pirotta et al.,
2022b). This includes determining how and to what degree various types
of anthropogenic sound cause stress in marine mammals and understanding
what factors may mitigate those physiological stress responses. Factors
potentially affecting an animal's response to a stressor include life
history, sex, age, reproductive status, overall physiological and
behavioral adaptability, and whether they are na[iuml]ve or experienced
with the sound (e.g., prior experience with a stressor may result in a
reduced response due to habituation)(Finneran and Branstetter, 2013;
St. Aubin and Dierauf, 2001). Because there are many unknowns regarding
the occurrence of acoustically induced stress responses in marine
mammals, any physiological response (e.g., hearing loss or injury) or
significant behavioral response is assumed to be associated with a
stress response.
Non-impulsive sources of sound can cause direct physiological
effects including noise-induced loss of hearing sensitivity (or
``threshold shift'') or other auditory injury, nitrogen decompression,
acoustically-induced bubble growth, and injury due to sound-induced
acoustic resonance. Separately, an animal's behavioral response to an
acoustic exposure might lead to physiological effects that might
ultimately lead to injury or death, which is discussed later in the
Stranding and Mortality section.
Heart Rate Response--
Several experimental studies have measured the heart rate response
of a variety of marine mammals. For example, Miksis et al. (2001)
observed increases in heart rates of captive bottlenose dolphins to
which known calls of other dolphins were played, although no increase
in heart rate was observed when background tank noise was played back.
However, it cannot be determined whether the increase in heart rate was
due to stress or social factors, such as expectation of an encounter
with a known conspecific. Similarly, a young captive beluga's heart
rate increased during exposure to noise, with increases dependent upon
the frequency band of noise and duration of exposure, and with a sharp
decrease to normal or below normal levels upon cessation of the
exposure (Lyamin et al., 2011). Spectral analysis of heart rate
variability corroborated direct measures of heart rate (Bakhchina et
al., 2017). This response might have been in part due to the conditions
during testing, the young age of the animal, and the novelty of the
exposure; a year later the exposure was repeated at a slightly higher
received level and there was no heart rate response, indicating the
beluga whale had potentially habituated to the noise exposure.
Kvadsheim et al. (2010a) measured the heart rate of captive hooded
seals during exposure to sonar signals and found an increase in the
heart rate of the seals during exposure periods versus control periods
when the animals were at the surface. When the animals dove, the normal
dive-related heart rate decrease was not impacted by the sonar
exposure. Similarly, Thompson et al. (1998) observed a rapid, short-
lived decrease in heart rates in wild harbor and grey seals exposed to
seismic air guns (cited in Gordon et al., 2003).
Two captive harbor porpoises showed significant bradycardia
(reduced heart rate), below that which occurs with diving, when they
were exposed to pinger-like sounds with frequencies between 100-140 kHz
(Teilmann et al., 2006). The bradycardia was found only in the early
noise exposures and the porpoises acclimated quickly across successive
noise exposures. Elmegaard et al. (2021) also found that initial
exposures to sonar sweeps produced bradycardia but did not elicit a
startle response in captive harbor porpoises. As with Teilmann et al.
(2006), the cardiac response disappeared over several repeat exposures
suggesting rapid acclimation to the noise. In the same animals, 40-kHz
noise pulses induced startle responses but without a change in heart
rate. Bakkeren et al. (2023) found no change in the heart rate of a
harbor porpoise during exposure to masking noise (\1/3\ octave band
noise, centered frequency of 125 kHz, maximum received level of 125 dB
re 1 [mu]Pa) during an echolocation task but showed significant
bradycardia while blindfolded for the same task. The authors attributed
the change in heart rate to sensory deprivation, although no strong
conclusions about acoustic masking could be made since the animal was
still able to perform the echolocation task in the presence of the
masking noise. Williams et al. (2022) observed periods of increased
heart rate variability in narwhals during seismic air gun impulse
exposure, but profound bradycardia was not noted. Conversely, Williams
et al. (2017) found that a profound bradycardia persisted in narwhals,
even though exercise effort increased dramatically as part of their
escape response following release from capture and handling.
Limited evidence across several different species suggests that
increased heart rate might occur as part of the acute stress response
of marine mammals that are at the surface. However, the decreased heart
rate typical of diving marine mammals can be enhanced in response to an
acute stressor, suggesting that the context of the exposure is critical
to understanding the cardiac response. Furthermore, in instances where
a cardiac response was noted, there appears to be rapid habituation
when repeat exposures occur. Additional research is required to
understand the interaction of dive bradycardia, noise-induced cardiac
responses, and the role of habituation in marine mammals.
Stress Hormone and Immune Response--
What is known about the function of the various stress hormones is
based largely upon observations of the stress response in terrestrial
mammals. The endocrine response of marine mammals to stress may not be
the same as that of terrestrial mammals because of the selective
pressures marine mammals faced during their evolution in an ocean
environment (Atkinson et al., 2015). For example, due to the necessity
of breath-holding while diving and foraging at depth, the physiological
role of epinephrine and norepinephrine (the catecholamines) might be
different in marine versus other mammals.
Catecholamines increase during breath-hold diving in seals, co-
occurring with a reduction in heart rate, peripheral vasoconstriction
(constriction of blood vessels), and an increased reliance on anaerobic
metabolism during extended dives (Hance et al., 1982; Hochachka et al.,
1995; Hurford et al., 1996); the catecholamine increase is not
associated with increased heart rate, glycemic release, and increased
oxygen consumption typical of terrestrial mammals. Captive belugas

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demonstrated no catecholamine response to the playback of oil drilling
sounds (Thomas et al., 1990b) but showed a small but statistically
significant increase in catecholamines following exposure to impulsive
sounds produced from a seismic water gun (Romano et al., 2004). A
captive bottlenose dolphin exposed to the same sounds did not
demonstrate a catecholamine response but did demonstrate a
statistically significant elevation in aldosterone (Romano et al.,
2004); however, the increase was within the normal daily variation
observed in this species (St. Aubin et al., 1996) and was likely of
little biological significance. Aldosterone has been speculated to not
only contribute to electrolyte balance, but possibly also the
maintenance of blood pressure during periods of vasoconstriction
(Houser et al., 2011). In marine mammals, aldosterone is thought to
play a role in mediating stress (St. Aubin & Dierauf, 2001; St. Aubin &
Geraci, 1989).
Yang et al. (2021) measured cortisol concentrations in two captive
bottlenose dolphins and found significantly higher concentrations after
exposure to 140 dB re 1 [mu]Pa impulsive noise playbacks. Two out of
six tested indicators of immune system function underwent acoustic
dose-dependent changes, suggesting that repeated exposures or sustained
stress response to impulsive sounds may increase an affected
individual's susceptibility to pathogens. Unfortunately, absolute
values of cortisol were not provided, and it is not possible from the
study to tell if cortisol rose to problematic levels (e.g., see normal
variation and changes due to handling in Houser et al. (2021) and
Champagne et al. (2018)). Exposing dolphins to a different acoustic
stressor yielded contrasting results. Houser et al. (2020) measured
cortisol and epinephrine obtained from 30 captive bottlenose dolphins
exposed to simulated Navy MFAS and found no correlation between SPL and
stress hormone levels, even though sound exposures were as high as 185
dB re 1 [mu]Pa. In the same experiment (Houser et al., 2013b),
behavioral responses were shown to increase in severity with increasing
received SPLs. These results suggest that behavioral responses to sonar
signals are not necessarily indicative of a hormonal stress response.
Whereas a limited amount of work has addressed the potential for
acute sound exposures to produce a stress response, almost nothing is
known about how chronic exposure to acoustic stressors affects stress
hormones in marine mammals, particularly as it relates to survival or
reproduction. In what is probably the only study of chronic noise
exposure in marine mammals associating changes in a stress hormone with
changes in anthropogenic noise, Rolland et al. (2012) compared the
levels of cortisol metabolites in NARW feces collected before and after
September 11, 2001. Following the events of September 11, 2001,
shipping was significantly reduced in the region where fecal
collections were made, and regional ocean background noise declined.
Fecal cortisol metabolites significantly decreased during the period of
reduced ship traffic and ocean noise (Rolland et al., 2012). Rolland et
al. (2017) also compared acute (death by vessel strike) to chronic
(entanglement or live stranding) stressors in NARW and found that
whales subject to chronic stressors had higher levels of glucocorticoid
stress hormones (cortisol and corticosterone) than either healthy
whales or those killed by ships. It was presumed that whales subjected
to acute stress may have died too quickly for increases in fecal
glucocorticoids to be detected.
Considerably more work has been conducted in an attempt to
determine the potential effect of vessel disturbance on smaller
cetaceans, particularly killer whales (Bain, 2002; Erbe, 2002; Lusseau,
2006; Noren et al., 2009; Pirotta et al., 2015b; Read et al., 2014;
Rolland et al., 2012; Williams et al., 2009; Williams et al., 2014a;
Williams et al., 2014b; Williams et al., 2006b). Most of these efforts
focused primarily on estimates of metabolic costs associated with
altered behavior or inferred consequences of boat presence and noise
but did not directly measure stress hormones. However, Ayres et al.
(2012) investigated Southern Resident killer whale fecal thyroid
hormone and cortisol metabolites to assess two potential threats to the
species' recovery: lack of prey (salmon) and impacts from exposure to
the physical presence of vessel traffic (but without measuring vessel
traffic noise). Ayres et al. (2012) concluded from these stress hormone
measures that the lack of prey overshadowed any population-level
physiological impacts on Southern Resident killer whales due to vessel
traffic. Lemos et al. (2022) investigated the potential for vessel
traffic to affect gray whales. By assessing gray whale fecal cortisol
metabolites across years in which vessel traffic was variable, Lemos et
al. (2022) found a direct relationship between the presence/density of
vessel traffic and fecal cortisol metabolite levels. Unfortunately, no
direct noise exposure measurements were made on any individual making
it impossible to tell if other natural and anthropogenic factors could
also be related to the results. Collectively, these studies indicate
the difficulty in determining which factors are primarily influence the
secretion of stress hormones, including the separate and additive
effects of vessel presence and vessel noise. While vessel presence
could contribute to the variation in fecal cortisol metabolites in NARW
and gray whales, there are other potential influences on fecal hormone
metabolites, so it is difficult to establish a direct link between
ocean noise and fecal hormone metabolites.
Non-Auditory Injury
Non-auditory injury, or direct injury, is considered less likely to
occur in the context of the Action Proponents' activities than auditory
injury and the primary anticipated source of non-auditory injury for
these activities is exposure to the pressure generated by explosive
detonations, which is discussed in the Potential Effects of Explosive
Sources on Marine Mammals section below. Here, we discuss less direct
non-auditory injury impacts, including acoustically induced bubble
formation, injury from sonar-induced acoustic resonance, and
behaviorally mediated injury.
One theoretical cause of injury to marine mammals is rectified
diffusion (Crum and Mao, 1996), the process of increasing the size of a
bubble by exposing it to a sound field. This process could be
facilitated if the environment in which the ensonified bubbles exist is
supersaturated with gas. Repetitive diving by marine mammals can cause
the blood and some tissues to accumulate gas to a greater degree than
is supported by the surrounding environmental pressure (Ridgway and
Howard, 1979). The deeper and longer dives of some marine mammals (for
example, beaked whales) are theoretically predicted to induce greater
supersaturation (Houser et al., 2001b). If rectified diffusion were
possible in marine mammals exposed to high-level sound, conditions of
tissue supersaturation could theoretically speed the rate and increase
the size of bubble growth. Subsequent effects due to tissue trauma and
emboli would presumably mirror those observed in humans suffering from
decompression sickness. Acoustically-induced (or mediated) bubble
growth and other pressure-related physiological impacts are addressed
below but are not expected to result from the Action Proponents'
proposed activities.

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It is unlikely that the short duration (in combination with the
source levels) of sonar pings would be long enough to drive bubble
growth to any substantial size, if such a phenomenon occurs. However,
an alternative but related hypothesis has also been suggested: stable
bubbles could be destabilized by high-level sound exposures such that
bubble growth then occurs through static diffusion of gas out of the
tissues. In such a scenario the marine mammal would need to be in a
gas-supersaturated state for a long enough period of time for bubbles
to become of a problematic size. Recent research with ex vivo
supersaturated bovine tissues suggested that, for a 37 kHz signal, a
sound exposure of approximately 215 dB referenced to (re) 1 [mu]Pa
would be required before microbubbles became destabilized and grew
(Crum et al., 2005). Assuming spherical spreading loss and a nominal
sonar source level of 235 dB re 1 [mu]Pa at 1 m, a whale would need to
be within 33 ft (10 m) of the sonar dome to be exposed to such sound
levels. Furthermore, tissues in the study were supersaturated by
exposing them to pressures of 400-700 kilopascals for periods of hours
and then releasing them to ambient pressures. Assuming the
equilibration of gases with the tissues occurred when the tissues were
exposed to the high pressures, levels of supersaturation in the tissues
could have been as high as 400-700 percent. These levels of tissue
supersaturation are substantially higher than model predictions for
marine mammals (Fahlman et al., 2009; Fahlman et al., 2014; Houser et
al., 2001; Saunders et al., 2008). It is improbable that this mechanism
is responsible for stranding events or traumas associated with beaked
whale strandings because both the degree of supersaturation and
exposure levels observed to cause microbubble destabilization are
unlikely to occur, either alone or in concert.
Yet another hypothesis (decompression sickness) has speculated that
rapid ascent to the surface following exposure to a startling sound
might produce tissue gas saturation sufficient for the evolution of
nitrogen bubbles (Jepson et al., 2003; Fernandez et al., 2005;
Fern[aacute]ndez et al., 2012). In this scenario, the rate of ascent
would need to be sufficiently rapid to compromise behavioral or
physiological protections against nitrogen bubble formation.
Alternatively, Tyack et al. (2006) studied the deep diving behavior of
beaked whales and concluded that: ``Using current models of breath-hold
diving, we infer that their natural diving behavior is inconsistent
with known problems of acute nitrogen supersaturation and embolism.''
Collectively, these hypotheses can be referred to as ``hypotheses of
acoustically mediated bubble growth.''
Although theoretical predictions suggest the possibility for
acoustically mediated bubble growth, there is considerable disagreement
among scientists as to its likelihood (Piantadosi and Thalmann, 2004;
Evans and Miller, 2003; Cox et al., 2006; Rommel et al., 2006). Crum
and Mao (1996) hypothesized that received levels would have to exceed
190 dB in order for there to be the possibility of significant bubble
growth due to supersaturation of gases in the blood (i.e., rectified
diffusion). Work conducted by Crum et al. (2005) demonstrated the
possibility of rectified diffusion for short duration signals, but at
SELs and tissue saturation levels that are highly improbable to occur
in diving marine mammals. To date, energy levels predicted to cause in
vivo bubble formation within diving cetaceans have not been evaluated
(NOAA, 2002b). Jepson et al. (2003, 2005) and Fernandez et al. (2004,
2005, 2012) concluded that in vivo bubble formation, which may be
exacerbated by deep, long-duration, repetitive dives may explain why
beaked whales appear to be relatively vulnerable to MFAS/HFAS
exposures. It has also been argued that traumas from some beaked whale
strandings are consistent with gas emboli and bubble-induced tissue
separations (Jepson et al., 2003); however, there is no conclusive
evidence of this (Rommel et al., 2006). Based on examination of sonar-
associated strandings, Bernaldo de Quiros et al. (2019) list diagnostic
features, the presence of all of which suggest gas and fat embolic
syndrome for beaked whales stranded in association with sonar exposure.
As described in additional detail in the Behaviorally Mediated
Injury section of appendix D the 2024 AFTT Draft Supplemental EIS/OEIS,
marine mammals generally are thought to deal with nitrogen loads in
their blood and other tissues, caused by gas exchange from the lungs
under conditions of high ambient pressure during diving, through
anatomical, behavioral, and physiological adaptations (Hooker et al.,
2012). Although not a direct injury, variations in marine mammal diving
behavior or avoidance responses have been hypothesized to result in
nitrogen off-gassing in super-saturated tissues, possibly to the point
of deleterious vascular and tissue bubble formation (Hooker et al.,
2012; Jepson et al., 2003; Saunders et al., 2008) with resulting
symptoms similar to decompression sickness, however the process is
still not well understood.
In 2009, Hooker et al. tested two mathematical models to predict
blood and tissue tension N2 (PN2) using field data from
three beaked whale species: northern bottlenose whales, goose-beaked
whales, and Blainville's beaked whales. The researchers aimed to
determine if physiology (body mass, diving lung volume, and dive
response) or dive behavior (dive depth and duration, changes in ascent
rate, and diel behavior) would lead to differences in PN2
levels and thereby decompression sickness risk between species. In
their study, they compared results for previously published time depth
recorder data (Hooker and Baird, 1999; Baird et al., 2006, 2008) from
goose-beaked whale, Blainville's beaked whale, and northern bottlenose
whale. They reported that diving lung volume and extent of the dive
response had a large effect on end-dive PN2. Also, results
showed that dive profiles had a larger influence on end-dive
PN2 than body mass differences between species. Despite diel
changes (i.e., variation that occurs regularly every day or most days)
in dive behavior, PN2 levels showed no consistent trend.
Model output suggested that all three species live with tissue
PN2 levels that would cause a significant proportion of
decompression sickness cases in terrestrial mammals. The authors
concluded that the dive behavior of goose-beaked whale was different
from both Blainville's beaked whale and northern bottlenose whale, and
resulted in higher predicted tissue and blood N2 levels (Hooker et al.,
2009). They also suggested that the prevalence of goose-beaked whales
stranding after naval sonar exercises could be explained by either a
higher abundance of this species in the affected areas or by possible
species differences in behavior and/or physiology related to MF active
sonar (Hooker et al., 2009).
Bernaldo de Quiros et al. (2012) showed that, among stranded
whales, deep diving species of whales had higher abundances of gas
bubbles compared to shallow diving species. Kvadsheim et al. (2012)
estimated blood and tissue PN2 levels in species
representing shallow, intermediate, and deep diving cetaceans following
behavioral responses to sonar and their comparisons found that deep
diving species had higher end-dive blood and tissue N2 levels,
indicating a higher risk of developing gas bubble emboli compared with
shallow diving species. Fahlmann et al. (2014) evaluated dive data
recorded from sperm, killer, long-finned pilot, Blainville's, and
goose-beaked whales before and during

[[Page 19933]]

exposure to low-frequency (1-2 kHz), as defined by the authors, and
mid-frequency (2-7 kHz) active sonar in an attempt to determine if
either differences in dive behavior or physiological responses to sonar
are plausible risk factors for bubble formation. The authors suggested
that CO2 may initiate bubble formation and growth, while
elevated levels of N2 may be important for continued bubble growth. The
authors also suggest that if CO2 plays an important role in
bubble formation, a cetacean escaping a sound source may experience
increased metabolic rate, CO2 production, and alteration in
cardiac output, which could increase risk of gas bubble emboli.
However, as discussed in Kvadsheim et al. (2012), the actual observed
behavioral responses to sonar from the species in their study (sperm,
killer, long-finned pilot, Blainville's beaked, and goose-beaked
whales) did not imply any significantly increased risk of decompression
sickness due to high levels of N2. Therefore, further information is
needed to understand the relationship between exposure to stimuli,
behavioral response (discussed in more detail below), elevated N2
levels, and gas bubble emboli in marine mammals. The hypotheses for gas
bubble formation related to beaked whale strandings is that beaked
whales potentially have strong avoidance responses to MFAS because they
sound similar to their main predator, the killer whale (Cox et al.,
2006; Southall et al., 2007; Zimmer and Tyack, 2007; Baird et al.,
2008; Hooker et al., 2009). Further investigation is needed to assess
the potential validity of these hypotheses.
To summarize, while there are several hypotheses, there is little
data directly connecting intense, anthropogenic underwater sounds with
non-auditory physical effects in marine mammals. The available data do
not support identification of a specific exposure level above which
non-auditory effects can be expected (Southall et al., 2007) or any
meaningful quantitative predictions of the numbers (if any) of marine
mammals that might be affected in these ways. In addition, such
effects, if they occur at all, would be expected to be limited to
situations where marine mammals were exposed to high powered sounds at
very close range over a prolonged period of time, which is not expected
to occur based on the speed of the vessels operating sonar in
combination with the speed and behavior of marine mammals in the
vicinity of sonar.
An object exposed to its resonant frequency will tend to amplify
its vibration at that frequency, a phenomenon called acoustic
resonance. Acoustic resonance has been proposed as a potential
mechanism by which a sonar or sources with similar operating
characteristics could damage tissues of marine mammals. In 2002, NMFS
convened a panel of government and private scientists to investigate
the potential for acoustic resonance to occur in marine mammals (NOAA,
2002). They modeled and evaluated the likelihood that Navy MFAS (2-10
kHz) caused resonance effects in beaked whales that eventually led to
their stranding. The workshop participants concluded that resonance in
air-filled structures was not likely to have played a primary role in
the Bahamas stranding in 2000. They listed several reasons supporting
this finding including (among others): tissue displacements at
resonance are estimated to be too small to cause tissue damage (i.e.,
non-auditory injury); tissue-lined air spaces most susceptible to
resonance are too large in marine mammals to have resonant frequencies
in the ranges used by MFAS or LFAS; lung resonant frequencies increase
with depth, and tissue displacements decrease with depth so if
resonance is more likely to be caused at depth it is also less likely
to have an affect there; and lung tissue damage has not been observed
in any mass, multi-species stranding of beaked whales. The frequency at
which resonance was predicted to occur in the animals' lungs was 50 Hz,
well below the frequencies used by the MFAS systems associated with the
Bahamas event. The workshop participants focused on the March 2000
stranding of beaked whales in the Bahamas as high-quality data were
available, but the workshop report notes that the results apply to
other sonar-related stranding events. For the reasons given by the 2002
workshop participants, we do not anticipate injury due to sonar-induced
acoustic resonance from the Action Proponents' proposed activity.

Potential Effects of Explosive Sources on Marine Mammals

Underwater explosive detonations send a shock wave and sound energy
through the water and can release gaseous by-products, create an
oscillating bubble, or cause a plume of water to shoot up from the
water surface. The shock wave and accompanying noise are of most
concern to marine animals and the potential effects of an explosive
injury to marine mammals would consist of primary blast injury, which
refers to injuries resulting from the compression of a body exposed to
a blast wave. Blast effects are greatest at the gas-liquid interface
(Landsberg, 2000) and are usually observed as barotrauma of gas-
containing structures (e.g., lung, gastrointestinal tract) and
structural damage to the auditory system (Goertner, 1982; Greaves et
al., 1943; Hill, 1978; Office of the Surgeon General, 1991; Richmond et
al., 1973; Yelverton et al., 1973). Depending on the intensity of the
shock wave and size, location, and depth of the animal, an animal can
be injured, killed, suffer non-lethal physical effects, experience
hearing related effects with or without behavioral responses, or
exhibit temporary behavioral responses or tolerance from hearing the
blast sound. Generally, exposures to higher levels of impulse and
pressure levels would result in greater impacts to an individual
animal.
The near instantaneous high magnitude pressure change near an
explosion can injure an animal where tissue material properties
significantly differ from the surrounding environment, such as around
air-filled cavities in the lungs or gastrointestinal tract. Large
pressure changes at tissue-air interfaces in the lungs and
gastrointestinal tract may cause tissue rupture, resulting in a range
of injuries depending on degree of exposure. The lungs are typically
the first site to show any damage, while the solid organs (e.g., liver,
spleen, and kidney) are more resistant to blast injury (Clark & Ward,
1943). Odontocetes can also incur hemorrhaging in the acoustic fats in
the melon and jaw (Siebert et al., 2022). Recoverable injuries would
include slight lung injury, such as capillary interstitial bleeding,
and contusions to the gastrointestinal tract. More severe injuries,
such as tissue lacerations, major hemorrhage, organ rupture, or air in
the chest cavity (pneumothorax), would significantly reduce fitness and
likely cause death in the wild. Rupture of the lung may also introduce
air into the vascular system, producing air emboli that can cause a
stroke or heart attack by restricting oxygen delivery to critical
organs.
Injuries resulting from a shock wave take place at boundaries
between tissues of different densities. Different velocities are
imparted to tissues of different densities, and this can lead to their
physical disruption. Intestinal walls can bruise or rupture, with
subsequent hemorrhage and escape of gut contents into the body cavity.
Less severe gastrointestinal tract injuries include contusions,
petechiae (small red or purple spots caused by bleeding in the skin),
and slight hemorrhaging (Yelverton et al., 1973).

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Relatively little is known about auditory system trauma in marine
mammals resulting from explosive exposure, although it is assumed that
auditory structures would be vulnerable to blast injuries because the
ears are the most sensitive to pressure and, therefore, they are the
organs most sensitive to injury (Ketten, 2000). Sound-related damage
associated with sound energy from detonations can be theoretically
distinct from injury from the shock wave, particularly farther from the
explosion. If a noise is audible to an animal, it has the potential to
damage the animal's hearing by causing decreased sensitivity (Ketten,
1995). Lethal impacts are those that result in immediate death or
serious debilitation in or near an intense source and are not,
technically, pure acoustic trauma (Ketten, 1995). Sublethal impacts
include hearing loss, which is caused by exposures to perceptible
sounds. Severe damage (from the shock wave) to the ears includes
tympanic membrane rupture, fracture of the ossicles, damage to the
cochlea, hemorrhage, and cerebrospinal fluid leakage into the middle
ear. Moderate injury implies partial hearing loss due to tympanic
membrane rupture and blood in the middle ear. Permanent hearing loss
also can occur when the hair cells are damaged by one very loud event,
as well as by prolonged exposure to a loud noise or chronic exposure to
noise. The level of impact from blasts depends on both an animal's
location and, at outer zones, on its sensitivity to the residual noise
(Ketten, 1995). Auditory trauma was found in 2 humpback whales that
died after the detonation of a 11,023 lb (5,000 kg) explosive used off
Newfoundland during demolition of an offshore oil rig platform (Ketten
et al., 1993), but the proximity of the whales to the detonation was
unknown. Eardrum rupture was examined in submerged terrestrial mammals
exposed to underwater explosions (Richmond et al., 1973; Yelverton et
al., 1973); however, results may not be applicable to the anatomical
adaptations for underwater hearing in marine mammals.
In general, models predict that an animal would be less susceptible
to injury near the water surface because the pressure wave reflected
from the water surface would interfere with the direct path pressure
wave, reducing positive pressure exposure (Goertner, 1982; Yelverton &
Richmond, 1981). This is shown in the records of humans exposed to
blast while in the water, which show that the gastrointestinal tract
was more likely to be injured than the lungs, likely due to the
shallower exposure geometry of the lungs (i.e., closer to the water
surface) (Lance et al., 2015). Susceptibility would increase with
depth, until normal lung collapse (due to increasing hydrostatic
pressure) and increasing ambient pressures again reduce susceptibility
(Goertner, 1982). The only known occurrence of mortality or injury to a
marine mammal due to a Navy training event involving explosives
occurred in March 2011 in nearshore waters off San Diego, California,
at the Silver Strand Training Complex (see Strandings Associated with
Explosive Use section below).
Controlled tests with a variety of lab animals (mice, rats, dogs,
pigs, sheep, and other species) are the best data sources on actual
injury to mammals due to underwater exposure to explosions. In the
early 1970s, the Lovelace Foundation for Medical Education and Research
conducted a series of tests in an artificial pond at Kirtland Air Force
Base, New Mexico, to determine the effects of underwater explosions on
mammals, with the goal of determining safe ranges for human divers. The
resulting data were summarized in two reports (Richmond et al., 1973;
Yelverton et al., 1973). Specific physiological observations for each
test animal are documented in Richmond et al. (1973). Gas-containing
internal organs, such as lungs and intestines, were the principle
damage sites in submerged terrestrial mammals; this is consistent with
earlier studies of mammal exposures to underwater explosions in which
lungs were consistently the first areas to show damage, with less
consistent damage observed in the gastrointestinal tract (Clark & Ward,
1943; Greaves et al., 1943).
In the Lovelace studies, the first positive acoustic impulse was
found to be the metric most related to degree of injury, and size of an
animal's gas-containing cavities was thought to play a role in blast
injury susceptibility. For these shallow exposures of small terrestrial
mammals (masses ranging from 3.4 to 50 kg) to underwater detonations,
Richmond et al. (1973) reported that no blast injuries were observed
when exposures were less than 6 pounds per square inch per millisecond
(psi-ms) (40 pascal seconds (Pa-s)), no instances of slight lung
hemorrhage occurred below 20 psi-ms (140 Pa-s), and instances of no
lung damage were observed in some exposures at higher levels up to 40
psi-ms (280 Pa-s). An impulse of 34 psi-ms (230 Pa-s) resulted in about
50 percent incidence of slight lung hemorrhage. About half of the
animals had gastrointestinal tract contusions (with slight ulceration,
i.e., some perforation of the mucosal layer) at exposures of 25-27 psi-
ms (170-190 Pa-s). Lung injuries were found to be slightly more
prevalent than gastrointestinal tract injuries for the same exposure.
The anatomical differences between the terrestrial animals used in the
Lovelace tests and marine mammals are summarized in Fetherston et al.
(2019). Goertner (1982) examined how lung cavity size would affect
susceptibility to blast injury by considering both marine mammal size
and depth in a bubble oscillation model of the lung; however, the
Goertner (1982) model did not consider how tissues surrounding the
respiratory air spaces would reflect shock wave energy or constrain
oscillation (Fetherston et al., 2019).
Goertner (1982) suggested a peak overpressure gastrointestinal
tract injury criterion because the size of gas bubbles in the
gastrointestinal tract are variable, and their oscillation period could
be short relative to primary blast wave exposure duration. The
potential for gastrointestinal tract injury, therefore, may not be
adequately modeled by the single oscillation bubble methodology used to
estimate lung injury due to impulse. Like impulse, however, high
instantaneous pressures may damage many parts of the body, but damage
to the gastrointestinal tract is used as an indicator of any peak
pressure-induced injury due to its vulnerability.
Because gas-containing organs are more vulnerable to primary blast
injury, adaptations for diving that allow for collapse of lung tissues
with depth may make animals less vulnerable to lung injury with depth.
Adaptations for diving include a flexible thoracic cavity, distensible
veins that can fill space as air compresses, elastic lung tissue, and
resilient tracheas with interlocking cartilaginous rings that provide
strength and flexibility (Ridgway, 1972). Denk et al. (2020) found
intra-species differences in the compliance of tracheobronchial
structures of post-mortem cetaceans and pinnipeds under diving
hydrostatic pressures, which would affect depth of alveolar collapse.
Older literature suggested complete lung collapse depths at
approximately 229.7 ft (70 m) for dolphins (Ridgway & Howard, 1979) and
65.6 to 164 ft (20 to 50 m) for phocid seals (Falke et al., 1985;
Kooyman et al., 1972). Follow-on work by Kooyman and Sinnett (1982), in
which pulmonary shunting was studied in harbor seals and sea lions,
suggested that complete lung collapse for these species would be about
557.7 ft (170 m) and about 590.6 (180 m), respectively. Evidence in sea
lions suggests that

[[Page 19935]]

complete collapse might not occur until depths as great as 738.2 ft
(225 m); although the depth of collapse and depth of the dive are
related, sea lions can affect the depth of lung collapse by varying the
amount of air inhaled on a dive (McDonald and Ponganis, 2012). This is
an important consideration for all divers who can modulate lung volume
and gas exchange prior to diving via the degree of inhalation and
during diving via exhalation (Fahlman et al., 2009); indeed, there are
noted differences in pre-dive respiratory behavior, with some marine
mammals exhibiting pre-dive exhalation to reduce the lung volume (e.g.,
phocid seals) (Kooyman et al., 1973).

Further Potential Effects of Behavioral Disturbance on Marine Mammal
Fitness

The different ways that marine mammals respond to sound are
sometimes indicators of the ultimate effect that exposure to a given
stimulus will have on the well-being (survival, reproduction, etc.) of
an animal. The long-term consequences of disturbance, hearing loss,
chronic masking, and acute or chronic physiological stress are
difficult to predict because of the different factors experienced by
individual animals, such as context of stressor exposure, underlying
health conditions, and other environmental or anthropogenic stressors.
Linking these non-lethal effects on individuals to changes in
population growth rates requires long-term data, which is lacking for
many populations. We summarize several studies below, but there are few
quantitative marine mammal data relating the exposure of marine mammals
to sound to effects on reproduction or survival, though data exists for
terrestrial species to which we can draw comparisons for marine
mammals. Several authors have reported that disturbance stimuli may
cause animals to abandon nesting and foraging sites (Sutherland and
Crockford, 1993); may cause animals to increase their activity levels
and suffer premature deaths or reduced reproductive success when their
energy expenditures exceed their energy budgets (Daan et al., 1996;
Feare, 1976; Mullner et al., 2004); or may cause animals to experience
higher predation rates when they adopt risk-prone foraging or migratory
strategies (Frid and Dill, 2002). Each of these studies addressed the
consequences of animals shifting from one behavioral state (e.g.,
resting or foraging) to another behavioral state (e.g., avoidance or
escape behavior) because of human disturbance or disturbance stimuli.
Lusseau and Bejder (2007) present data from three long-term studies
illustrating the connections between disturbance from whale-watching
boats and population-level effects in cetaceans. In Shark Bay
Australia, the abundance of bottlenose dolphins was compared within
adjacent control and tourism sites over three consecutive 4.5-year
periods of increasing tourism levels. Between the second and third time
periods, in which tourism doubled, dolphin abundance decreased by 15
percent in the tourism area and did not change significantly in the
control area. In Fiordland, New Zealand, two populations (Milford and
Doubtful Sounds) of bottlenose dolphins with tourism levels that
differed by a factor of seven were observed and significant increases
in travelling time and decreases in resting time were documented for
both. Consistent short-term avoidance strategies were observed in
response to tour boats until a threshold of disturbance was reached
(average 68 minutes between interactions), after which the response
switched to a longer-term habitat displacement strategy. For one
population, tourism only occurred in a part of the home range. However,
tourism occurred throughout the home range of the Doubtful Sound
population and once boat traffic increased beyond the 68-minute
threshold (resulting in abandonment of their home range/preferred
habitat), reproductive success drastically decreased (increased
stillbirths) and abundance decreased significantly (from 67 to 56
individuals in a short period). Last, in a study of Northern Resident
killer whales off Vancouver Island, exposure to boat traffic was shown
to reduce foraging opportunities and increase traveling time. A simple
bioenergetics model was applied to show that the reduced foraging
opportunities equated to a decreased energy intake of 18 percent, while
the increased traveling incurred an increased energy output of 3-4
percent, which suggests that a management action based on avoiding
interference with foraging might be particularly effective.
An important variable to consider is duration of disturbance.
Severity scales used to assess behavioral responses or marine mammals
to acute sound exposures are not appropriate to apply to sustained or
chronic exposures, which requires considering the health of a
population over time rather than a focus on immediate impacts to
individuals (Southall et al., 2021). For example, short-term costs
experienced over the course of a week by an otherwise healthy
individual may be recouped over time after exposure to the stressor
ends. These short-term costs would be unlikely to result in long-term
consequences to that individual or to that individual's population.
Comparatively, long-term costs accumulated by otherwise healthy
individuals over an entire season, year, or throughout a life stage
(e.g., pup, juvenile, adult) would be less easily recouped and more
likely to result in long-term consequences to that individual or
population.
Marine mammals exposed to frequent or intense anthropogenic
activities may leave the area, habituate to the activity, or tolerate
the disturbance and remain in the area (Wartzok et al., 2003). Highly
resident or localized populations may also stay in an area of
disturbance because the cost of displacement is higher than the cost of
remaining in the area (Forney et al., 2017). As such, an apparent lack
of response (e.g., no displacement or avoidance of a sound source) does
not necessarily indicate there is no cost to the individual or
population, as some resources or habitats may be of such high value
that animals may choose to stay, even when experiencing the
consequences of stress, masking, or hearing loss (Forney et al., 2017).
Longer term displacement can lead to changes in abundance or
distribution patterns of the species in the affected region (Bejder et
al., 2006b; Blackwell et al., 2004; Teilmann et al., 2006). For
example, gray whales in Baja California, Mexico, abandoned a historical
breeding lagoon in the mid-1960s due to an increase in dredging and
commercial shipping operations, and only repopulated the lagoon after
shipping activities had ceased for several years (Bryant et al., 1984).
Mysticetes in the northeast tended to adjust to vessel traffic over
several years, trending towards more neutral behavioral responses to
passing vessels (Watkins, 1986), indicating that some animals may
habituate to high levels of human activity. A study on bottlenose
dolphin responses to vessel approaches found that lesser responses in
populations of dolphins regularly subjected to high levels of vessel
traffic could be a sign of habituation, or it could be that the more
sensitive animals in this population previously abandoned the area of
higher human activity (Bejder et al., 2006a).
Population characteristics (e.g., whether a population is open or
closed to immigration and emigration) can influence sensitivity to
disturbance as well; closed populations could not withstand a higher
probability of disturbance compared to open

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populations with no limitation on food (New et al., 2020). Predicting
population trends or long-term displacement patterns due to
anthropogenic disturbance is challenging due to limited information and
survey data for many species over sufficient spatiotemporal scales, as
well as a full understanding of how other factors, such as
oceanographic oscillations and climate change, affect marine mammal
presence (Moore and Barlow, 2013; Barlow, 2016; Moore and Barlow,
2017).
Population models are necessary to understand and link short-term
effects to individuals from disturbance (anthropogenic impacts or
environmental change) to long-term population consequences. Population
models require inputs for the population size and changes in vital
rates of the population (e.g., the mean values for survival age,
lifetime reproductive success, recruitment of new individuals into the
population), to predict changes in population dynamics (e.g.,
population growth rate). These efforts often rely on bioenergetic
models, or energy budget models, which analyze energy intake from food
and energy costs for life functions, such as maintenance, growth, and
reproduction, either at the individual or population level (Pirotta,
2022), and model sensitivity analyses have identified the most
consequential parameters, including prey characteristics, feeding
processes, energy expenditure, body size, energy storage, and lactation
capability (Pirotta, 2022). However, there is a high level of
uncertainty around many parameters in these models (H[uuml]tt et al.,
2023).
The U.S. National Research Council (NRC) committee on
Characterizing Biologically Significant Marine Mammal Behavior
developed an initial conceptual model to link acoustic disturbance to
population effects and inform data and research needs (NRC, 2005). This
Population Consequences of Acoustic Disturbance, or PCAD, conceptual
model linked the parameters of sound exposure, behavior change, life
function immediately affected, vital rates, and population effects. In
its report, the committee found that the relationships between vital
rates and population effects were relatively well understood, but that
the relationships between the other components of the model were not
well-known or easily observed.
Following the PCAD framework (NRC, 2005), an ONR working group
developed the Potential Consequences of Disturbance (PCoD), outlining
an updated conceptual model of the relationships linking disturbance to
changes in behavior and physiology, health, vital rates, and population
dynamics. The PCoD model considers all types of disturbance, not solely
anthropogenic or acoustic, and incorporates physiological changes, such
as stress or injury, along with behavioral changes as a direct result
of disturbance (National Academies of Sciences Engineering and
Medicine, 2017). In this framework, behavioral and physiological
changes can have direct (acute) effects on vital rates, such as when
changes in habitat use or increased stress levels raise the probability
of mother-calf separation or predation; they can have indirect and
long-term (chronic) effects on vital rates, such as when changes in
time/energy budgets or increased disease susceptibility affect health,
which then affects vital rates; or they can have no effect to vital
rates (New et al., 2014; Pirotta et al., 2018a). In addition to
outlining this general framework and compiling the relevant literature
that supports it, the authors chose four example species for which
extensive long-term monitoring data exist (southern elephant seals,
NARW, Ziphidae beaked whales, and bottlenose dolphins) and developed
state-space energetic models that can be used to forecast longer-term,
population-level impacts from behavioral changes. While these are very
specific models with very specific data requirements that cannot yet be
applied broadly to project-specific risk assessments for the majority
of species, as well as requiring significant resources and time to
conduct (more than is typically available to support regulatory
compliance for one project), they are a critical first step towards
being able to quantify the likelihood of a population level effect.
Since New et al. (2014), several publications have described models
developed to examine the long-term effects of environmental or
anthropogenic disturbance of foraging on various life stages of
selected species (sperm whale, Farmer et al. (2018); California sea
lion, McHuron et al. (2018); and blue whale, Pirotta, et al. (2018a)).
The PCoD model identifies the types of data that would be needed to
assess population-level impacts. These data are lacking for many marine
mammal species (Booth et al., 2020). Southall et al. (2021) states that
future modeling and population simulation studies can help determine
population-wide long-term consequences and impact analysis. However,
the method to do so is still developing, as there are gaps in the
literature, possible sampling biases, and results are rarely ground-
truthed, with a few exceptions (Booth et al., 2022; Schwarz et al.,
2022). Nowacek et al. (2016) reviewed technologies such as passive
acoustic monitoring, tagging, and the use of unmanned aerial vehicles
which can improve scientists' abilities to study these model inputs and
link behavioral changes to individual life functions and ultimately
population-level effects. Relevant data needed for improving analyses
of population-level consequences resulting from disturbances will
continue to be collected during the 7-year period of the LOAs through
projects funded by the Navy's Marine Species Monitoring Program.
Multiple case studies across marine mammal taxonomic groups have been
conducted following the PCoD framework. From these studies, Keen et al.
(2021) identified themes and contextual factors relevant to assessing
impacts to populations due to disturbance, which have been considered
in the context of the impacts of the Action Proponents' activities.
A population's movement ecology determines the potential for
spatiotemporal overlap with a disturbance. Resident populations or
populations that rely on spatially limited habitats for critical life
functions (i.e., foraging, breeding) would be at greater risk of
repeated or chronic exposure to disturbances than populations that are
wide-ranging relative to the footprint of a disturbance (Keen et al.,
2021). Even for the same species, differences in habitat use between
populations can result in different potential for repeated exposure to
individuals for a similar stressor (Costa et al., 2016a). The location
and radius of disturbance can impact how many animals are exposed and
for how long (Costa et al., 2016b). While some models have shown the
advantages of populations with larger ranges, namely the decreased
chance of being exposed (Costa et al., 2016b), it's important to
consider that for some species, the energetic cost of a longer
migration could make a population more sensitive to energy lost through
disturbance (Villegas-Amtmann et al., 2017). In addition to ranging
patterns, a species' activity budgets and lunging rates can cause
variability in their predicted cost of disturbance as well (Pirotta et
al., 2021).
Bioenergetics frameworks that examine the impact of foraging
disruption on body reserves of individual whales found that rates of
daily foraging disruption can predict the number of days to terminal
starvation for various life stages (Farmer et al.,

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2018b). Similarly, when a population is displaced by a stressor, and
only has access to areas of poor habitat quality (i.e., low prey
abundance) for relocation, bioenergetic models may be more likely to
predict starvation, longer recovery times, or extinction (Hin et al.,
2023). There is some debate over the use of blubber thickness as a
metric of cetacean energy stores and health, as marine mammals may not
use their fat stores in a similar manner to terrestrial mammals (Derous
et al., 2020).
Resource limitation can impact marine mammal population growth rate
regardless of additional anthropogenic disturbance. Stochastic Dynamic
Programming models have been used to explore the impact declining prey
species has on focal marine mammal predators (McHuron et al., 2023a;
McHuron et al., 2023b). A Stochastic Dynamic Programming model
determined that a decrease in walleye pollock (Gadus chalcogrammus)
availability increased the time and distance northern fur seal mothers
had to travel offshore, which negatively impacted pup growth rate and
wean mass, despite attempts to compensate with longer recovery time on
land (McHuron et al., 2023b). Prey is an important factor in long-term
consequence models for many species of marine mammals. In disturbance
models that predict habitat displacement or otherwise reduced foraging
opportunities, populations are being deprived of energy dense prey or
``high quality'' areas which can lead to long-term impacts on fecundity
and survival (Czapanskiy et al., 2021; Hin et al., 2019; McHuron et
al., 2023a; New et al., 2013b). Prey density limits the energy
available for growth, reproduction, and survival. Some disturbance
models indicate that the immediate decrease in a portion of the
population (e.g., young lactating mothers) is not necessarily
detrimental to a population, since as a result, prey availability
increases and the population's overall improved body condition reduces
the age at first calf (Hin et al., 2021). The timing of a disturbance
with seasonally available resources is also important; if a disturbance
occurs during periods of low resource availability, the population-
level consequences are greater and occur faster than if the disturbance
occurs during periods when resource levels are high (Hin et al., 2019).
Further, when resources are not evenly distributed, populations with
cautious strategies and knowledge of resource variation have an
advantage (Pirotta et al., 2020).
Even when modeled alongside several anthropogenic sources of
disturbance (e.g., vessel strike, vessel noise, chemical contaminants,
sonar), several species of marine mammals are most influenced by lack
of prey (Czapanskiy et al., 2021; Murray et al., 2021). Some species
like killer whales are especially sensitive to prey abundance due to
their limited diet (Murray et al., 2021). The short-term energetic cost
of eleven species of cetaceans and mysticetes exposed to mid-frequency
active sonar was influenced more by lost foraging opportunities than
increased locomotor effort during avoidance (Czapanskiy et al., 2021).
Additionally, the model found that mysticetes incurred more energetic
cost than odontocetes, even during mild behavioral responses to sonar.
These results may be useful in the development of future Population
Consequences of Multiple Stressors and PCoD models since they should
seek to qualify cetacean health in a more ecologically relevant manner.
PCoD models have been used to assess the impacts of multiple and
recurring stressors. A marine mammal population that is already subject
to chronic stressors like climate change will likely be more vulnerable
to acute disturbances. Models that have looked at populations of
cetaceans who are exposed to multiple stressors over several years have
found that even one major chronic stressor (e.g., climate change,
epizootic disease, oil spill) has severe impacts on population size. A
layer of one or more stressor (e.g., seismic surveys) in addition to a
chronic stressor (like an oil spill) can yield devastating impacts on a
population. These results may vary based on species and location, as
one population may be more impacted by chronic shipping noise, while
another population may not. However, just because a population doesn't
appear to be impacted by one chronic stressor (e.g., shipping noise),
does not mean they aren't affected by others, such as climate change or
disease (Reed et al., 2020). Recurring or chronic stressors can impact
population abundance even when instances of disturbance are short and
have minimal behavioral impact on an individual (Farmer et al., 2018a;
McHuron et al., 2018b; Pirotta et al., 2019). Some changes to response
variables like pup recruitment (survival to age one) aren't noticeable
for several years, as the impacts on pup survival does not affect the
population until those pups are mature but impacts to young animals
will ultimately lead to population-wide declines. The severity of the
repeated disturbance can also impact a population's long-term
reproductive success. Scenarios with severe repeated disturbance (e.g.,
95 percent probability of exposure, with 95 percent reduction in
feeding efficiency) can severely reduce fecundity and calf survival,
while a weaker disturbance (25 percent probability of exposure, with 25
percent reduction in feeding efficiency) had no population-wide effect
on vital rates (Pirotta et al., 2019).
Farmer et al. (2018a) modeled how an oil spill led to chronic
declines in a sperm whale population over 10 years, and if models
included even one more stressor (i.e., behavioral responses to air
guns), the population declined even further. However, the amount of
additional population decline due to acoustic disturbance depended on
the way the dose-response of the noise levels were modeled. A single
step-function led to higher impacts than a function with multiple steps
and frequency weighting. In addition, the amount of impact from both
disturbances was mediated when the metric in the model that described
animal resilience was changed to increase resilience to disturbance
(e.g., able to make up reserves through increased foraging).
Not all stressors have the same impact for all species and all
locations. Another model analyzed the effect of a number of chronic
disturbances on two bottlenose dolphin populations in Australia over 5
years (Reed et al., 2020). Results indicated that disturbance from
fisheries interactions and shipping noise had little overall impact on
population abundances in either location, even in the most extreme
impact scenarios modeled. At least in this area, epizootic and climate
change scenarios had the largest impact on population size and
fecundity.
Recurring stressors can impact population abundance even when
individual instances of disturbance are short and have minimal
behavioral impact on an individual. A model on California sea lions
introduced a generalized disturbance at different times throughout the
breeding cycle, with their behavior response being an increase in the
duration of a foraging trip by the female (McHuron et al., 2018b). Very
short duration disturbances or responses led to little change,
particularly if the disturbance was a single event, and changes in the
timing of the event in the year had little effect. However, with even
relatively short disturbances or mild responses, when a disturbance was
modeled as recurring there were resulting reductions in population size
and pup recruitment (survival to age one). Often,

[[Page 19938]]

the effects weren't noticeable for several years, as the impacts on pup
survival did not affect the population until those pups were mature.

Stranding and Mortality

The definition for a stranding under title IV of the MMPA is that
(A) a marine mammal is dead and is (i) on a beach or shore of the
United States; or (ii) in waters under the jurisdiction of the United
States (including any navigable waters); or (B) a marine mammal is
alive and is (i) on a beach or shore of the United States and is unable
to return to the water; (ii) on a beach or shore of the United States
and, although able to return to the water, is in need of apparent
medical attention; or (iii) in the waters under the jurisdiction of the
United States (including any navigable waters), but is unable to return
to its natural habitat under its own power or without assistance (see
MMPA section 410(3)). This definition is useful for considering
stranding events even when they occur beyond lands and waters under the
jurisdiction of the United States.
Marine mammal strandings have been linked to a variety of causes,
such as illness from exposure to infectious agents, biotoxins, or
parasites; starvation; unusual oceanographic or weather events; or
anthropogenic causes including fishery interaction, vessel strike,
entrainment, entrapment, sound exposure, or combinations of these
stressors sustained concurrently or in series. Historically, the cause
or causes of most strandings have remained unknown (Geraci et al.,
1976; Eaton, 1979, Odell et al., 1980; Best, 1982), but the development
of trained, professional stranding response networks and improved
analyses have led to a greater understanding of marine mammal stranding
causes (Simeone and Moore 2017).
Numerous studies suggest that the physiology, behavior, habitat,
social relationships, age, or condition of cetaceans may cause them to
strand or might predispose them to strand when exposed to another
phenomenon. These suggestions are consistent with the conclusions of
numerous other studies that have demonstrated that combinations of
dissimilar stressors commonly combine to kill an animal or dramatically
reduce its fitness, even though one exposure without the other does not
produce the same result (Bernaldo de Quiros et al., 2019; Chroussos,
2000; Creel, 2005; DeVries et al., 2003; Fair and Becker, 2000; Foley
et al., 2001; Moberg, 2000; Relyea, 2005a; 2005b, Romero, 2004; Sih et
al., 2004).
Historically, stranding reporting and response efforts have been
inconsistent, although significant improvements have occurred over the
last 25 years. Reporting forms for basic (``Level A'') information,
rehabilitation disposition, and human interaction have been
standardized nationally (available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/level-data-collection-marine-mammal-stranding-events). However, data collected beyond basic information
varies by region (and may vary from case to case), and are not
standardized across the United States. Logistical conditions such as
weather, time, location, and decomposition state may also affect the
ability of the stranding network to thoroughly examine a specimen
(Carretta et al., 2023; Moore et al., 2013). While the investigation of
stranded animals provides insight into the types of threats marine
mammal populations face, full investigations are only possible and
conducted on a small fraction of the total number of strandings that
occur, limiting our understanding of the causes of strandings (Carretta
et al., 2016a). Additionally, and due to the variability in effort and
data collected, the ability to interpret long-term trends in stranded
marine mammals is complicated.
In the United States from 2006-2022, there were 27,781 cetacean
strandings and 79,572 pinniped strandings (107,353 total) (P. Onens,
NMFS, pers comm., 2024). Several mass strandings (strandings that
involve two or more individuals of the same species, excluding a single
mother-calf pair) that have occurred over the past two decades have
been associated with anthropogenic activities that introduced sound
into the marine environment such as naval operations and seismic
surveys. An in-depth discussion of strandings can be found in appendix
D of the 2024 AFTT Draft Supplemental EIS/OEIS and in the Navy's
Technical Report on Marine Mammal Strandings Associated with U.S. Navy
Sonar Activities (U.S. Navy Marine Mammal Program & Space and Naval
Warfare Systems Command Center Pacific, 2017).
Worldwide, there have been several efforts to identify
relationships between cetacean mass stranding events and military
active sonar (Cox et al., 2006, Hildebrand, 2004; Taylor et al., 2004).
For example, based on a review of mass stranding events around the
world consisting of two or more individuals of goose-beaked whales,
records from the International Whaling Commission (IWC) (2005) show
that a quarter (9 of 41) were associated with concurrent naval patrol,
explosion, maneuvers, or MFAS. D'Amico et al. (2009) reviewed beaked
whale stranding data compiled primarily from the published literature,
which provides an incomplete record of stranding events, as many are
not written up for publication, along with unpublished information from
some regions of the world.
Most of the stranding events reviewed by the IWC involved beaked
whales. A mass stranding of goose-beaked whales in the eastern
Mediterranean Sea occurred in 1996 (Frantzis, 1998), and mass stranding
events involving Gervais' beaked whales, Blainville's beaked whales,
and goose-beaked whales occurred off the coast of the Canary Islands in
the late 1980s (Simmonds and Lopez-Jurado, 1991). The stranding events
that occurred in the Canary Islands and Kyparissiakos Gulf in the late
1990s and the Bahamas in 2000 have been the most intensively-studied
mass stranding events and have been associated with naval maneuvers
involving the use of tactical sonar. Other cetacean species with naval
sonar implicated in stranding events include harbor porpoise (Norman et
al., 2004, Wright et al., 2013) and common dolphin (Jepson and Deaville
2009).
Strandings Associated With Active Sonar
Over the past 21 years, there have been 5 stranding events
coincident with military MFAS use in which exposure to sonar is
believed to have been a contributing factor: Greece (1996); the Bahamas
(2000); Madeira (2000); Canary Islands (2002); and Spain (2006) (Cox et
al., 2006; Fernandez, 2006; U.S. Navy Marine Mammal Program & Space and
Naval Warfare Systems Command Center Pacific, 2017). These five mass
strandings have resulted in about 40 known cetacean deaths consisting
mostly of beaked whales and with close linkages to MFAS activity. In
these circumstances, exposure to non-impulsive acoustic energy was
considered a potential indirect cause of death of the marine mammals
(Cox et al., 2006). Only one of these stranding events, the Bahamas
(2000), was associated with exercises conducted by the U.S. Navy.
Additionally, in 2004, during the Rim of the Pacific (RIMPAC)
exercises, between 150 and 200 usually pelagic melon-headed whales
occupied the shallow waters of Hanalei Bay, Kaua'i, Hawaii for over 28
hours. NMFS determined that MFAS was a plausible, if not likely,
contributing factor in what may have been a confluence of events that
led to the Hanalei Bay stranding. A number of other stranding events
coincident with the operation of MFAS,

[[Page 19939]]

including the death of beaked whales or other species (minke whales,
dwarf sperm whales, pilot whales), have been reported; however, the
majority have not been investigated to the degree necessary to
determine the cause of the stranding. Most recently, the Independent
Scientific Review Panel investigating potential contributing factors to
a 2008 mass stranding of melon-headed whales in Antsohihy, Madagascar
released its final report suggesting that the stranding was likely
initially triggered by an industry seismic survey (Southall et al.,
2013). This report suggests that the operation of a commercial high-
powered 12 kHz multibeam echosounder during an industry seismic survey
was a plausible and likely initial trigger that caused a large group of
melon-headed whales to leave their typical habitat and then ultimately
strand as a result of secondary factors such as malnourishment and
dehydration. The report indicates that the risk of this particular
convergence of factors and ultimate outcome is likely very low, but
recommends that the potential be considered in environmental planning.
Because of the association between tactical MFAS use and a small number
of marine mammal strandings, the Navy and NMFS have been considering
and addressing the potential for strandings in association with Navy
activities for years. In addition to the proposed mitigation measures
intended to more broadly minimize impacts to marine mammals, the Navy
will abide by the Notification and Reporting Plan, which sets out
notification, reporting, and other requirements when dead, injured, or
stranded marine mammals are detected in certain circumstances.
Greece (1996)--
Twelve goose-beaked whales stranded atypically (in both time and
space) along a 23.7 mi (38.2 km) strand of the Kyparissiakos Gulf coast
on May 12 and 13, 1996 (Frantzis, 1998). From May 11 through May 15,
the North Atlantic Treaty Organization (NATO) research vessel Alliance
was conducting sonar tests with signals of 600 Hz and 3 kHz and source
levels of 228 and 226 dB re 1 [mu]Pa, respectively (D'Amico and
Verboom, 1998; D'Spain et al., 2006). The timing and location of the
testing encompassed the time and location of the strandings (Frantzis,
1998).
Necropsies of eight of the animals were performed but were limited
to basic external examination and sampling of stomach contents, blood,
and skin. No ears or organs were collected, and no histological samples
were preserved. No significant apparent abnormalities or wounds were
found, however examination of photos of the animals, taken soon after
their death, revealed that the eyes of at least four of the individuals
were bleeding (Frantzis, 2004). Stomach contents contained the flesh of
cephalopods, indicating that feeding had recently taken place
(Frantzis, 1998).
All available information regarding the conditions associated with
this stranding event was compiled, and many potential causes were
examined including major pollution events, prominent tectonic activity,
unusual physical or meteorological events, magnetic anomalies,
epizootics, and conventional military activities (International Council
for the Exploration of the Sea, 2005). However, none of these potential
causes coincided in time or space with the mass stranding, or could
explain its characteristics (International Council for the Exploration
of the Sea, 2005). The robust condition of the animals, plus the recent
stomach contents, is inconsistent with pathogenic causes. In addition,
environmental causes can be ruled out as there were no unusual
environmental circumstances or events before or during this time period
and within the general proximity (Frantzis, 2004).
Because of the rarity of this mass stranding of goose-beaked whales
in the Kyparissiakos Gulf (first one in historical records), the
probability for the two events (the military exercises and the
strandings) to coincide in time and location, while being independent
of each other, was thought to be extremely low (Frantzis, 1998).
However, because full necropsies had not been conducted, and no
abnormalities were noted, the cause of the strandings could not be
precisely determined (Cox et al., 2006). A Bioacoustics Panel convened
by NATO concluded that the evidence available did not allow them to
accept or reject sonar exposures as a causal agent in these stranding
events. The analysis of this stranding event provided support for, but
no clear evidence for, the cause-and-effect relationship of tactical
sonar training activities and beaked whale strandings (Cox et al.,
2006).
Bahamas (2000)--
NMFS and the Navy prepared a joint report addressing the multi-
species stranding in the Bahamas in 2000, which took place within 24
hours of U.S. Navy ships using MFAS as they passed through the
Northeast and Northwest Providence Channels on March 15-16, 2000. The
ships, which operated both AN/SQS-53C and AN/SQS-56, moved through the
channel while emitting sonar pings approximately every 24 seconds. Of
the 17 cetaceans that stranded over a 36-hour period (goose-beaked
whales, Blainville's beaked whales, minke whales, and a spotted
dolphin), 7 animals died on the beach (5 goose-beaked whales, 1
Blainville's beaked whale, and 1 spotted dolphin), while the other 10
were returned to the water alive (though their ultimate fate is
unknown). As discussed in the Bahamas report (DOC/DON, 2001), there is
no likely association between the minke whale and spotted dolphin
strandings and the operation of MFAS.
Necropsies were performed on five of the stranded beaked whales.
All five necropsied beaked whales were in good body condition, showing
no signs of infection, disease, vessel strike, blunt trauma, or fishery
related injuries, and three still had food remains in their stomachs.
Auditory structural damage was discovered in four of the whales,
specifically bloody effusions or hemorrhaging around the ears.
Bilateral intracochlear and unilateral temporal region subarachnoid
hemorrhage, with blood clots in the lateral ventricles, were found in
two of the whales. Three of the whales had small hemorrhages in their
acoustic fats (located along the jaw and in the melon).
A comprehensive investigation was conducted and all possible causes
of the stranding event were considered, whether they seemed likely at
the outset or not. Based on the way in which the strandings coincided
with ongoing naval activity involving tactical MFAS use, in terms of
both time and geography, the nature of the physiological effects
experienced by the dead animals, and the absence of any other acoustic
sources, the investigation team concluded that MFAS aboard U.S. Navy
ships that were in use during the active sonar exercise in question
were the most plausible source of this acoustic or impulse trauma to
beaked whales. This sound source was active in a complex environment
that included the presence of a surface duct, unusual and steep
bathymetry, a constricted channel with limited egress, intensive use of
multiple, active sonar units over an extended period of time, and the
presence of beaked whales that appear to be sensitive to the
frequencies produced by these active sonars. The investigation team
concluded that the cause of this stranding event was the confluence of
the Navy MFAS and these contributory factors working together, and
further recommended that the Navy avoid operating MFAS in situations
where these five factors would be likely to occur. This report does not
conclude

[[Page 19940]]

that all five of these factors must be present for a stranding to
occur, nor that beaked whales are the only species that could
potentially be affected by the confluence of the other factors. Based
on this, NMFS believes that the operation of MFAS in situations where
surface ducts exist, or in marine environments defined by steep
bathymetry and/or constricted channels may increase the likelihood of
producing a sound field with the potential to cause cetaceans
(especially beaked whales) to strand, and therefore, suggests the need
for increased vigilance while operating MFAS in these areas, especially
when beaked whales (or potentially other deep divers) are likely
present.
Madeira, Portugal (2000)--
From May 10-14, 2000, three goose-beaked whales were found
atypically stranded on two islands in the Madeira archipelago, Portugal
(Cox et al., 2006). A fourth animal was reported floating in the
Madeiran waters by fisherman but did not come ashore (Woods Hole
Oceanographic Institution, 2005). Joint NATO amphibious training
peacekeeping exercises involving participants from 17 countries and 80
warships, took place in Portugal during May 2-15, 2000.
The bodies of the three stranded whales were examined postmortem
(Woods Hole Oceanographic Institution, 2005), though only one of the
stranded whales was fresh enough (24 hours after stranding) to be
necropsied (Cox et al., 2006). Results from the necropsy revealed
evidence of hemorrhage and congestion in the right lung and both
kidneys (Cox et al., 2006). There was also evidence of intercochlear
and intracranial hemorrhage similar to that which was observed in the
whales that stranded in the Bahamas event (Cox et al., 2006). There
were no signs of blunt trauma, and no major fractures, and the cranial
sinuses and airways were found to be clear with little or no fluid
deposition, which may indicate good preservation of tissues (Woods Hole
Oceanographic Institution, 2005).
Several observations on the Madeira stranded beaked whales, such as
the pattern of injury to the auditory system, are the same as those
observed in the Bahamas strandings. Blood in and around the eyes,
kidney lesions, pleural hemorrhages, and congestion in the lungs are
particularly consistent with the pathologies from the whales stranded
in the Bahamas, and are consistent with stress and pressure related
trauma. The similarities in pathology and stranding patterns between
these two events suggest that a similar pressure event may have
precipitated or contributed to the strandings at both sites (Woods Hole
Oceanographic Institution, 2005).
Even though no definitive causal link can be made between the
stranding event and naval exercises, certain conditions may have
existed in the exercise area that, in their aggregate, may have
contributed to the marine mammal strandings (Freitas, 2004): exercises
were conducted in areas of at least 547 fathoms (1,000 m) depth near a
shoreline where there is a rapid change in bathymetry on the order of
547 to 3,281 fathoms (1,000 to 6,000 m) occurring across a relatively
short horizontal distance (Freitas, 2004); multiple ships were
operating around Madeira, though it is not known if MFAS was used, and
the specifics of the sound sources used are unknown (Cox et al., 2006;
Freitas, 2004); and exercises took place in an area surrounded by
landmasses separated by less than 35 nmi (65 km) and at least 10 nmi
(19 km) in length, or in an embayment. Exercises involving multiple
ships employing MFAS near land may produce sound directed towards a
channel or embayment that may cut off the lines of egress for marine
mammals (Freitas, 2004).
Canary Islands, Spain (2002)--
The southeastern area within the Canary Islands is well known for
aggregations of beaked whales due to its ocean depths of greater than
547 fathoms (1,000 m) within a few hundred meters of the coastline
(Fernandez et al., 2005). On September 24, 2002, 14 beaked whales were
found stranded on Fuerteventura and Lanzarote Islands in the Canary
Islands (International Council for Exploration of the Sea, 2005a).
Seven whales died, while the remaining seven live whales were returned
to deeper waters (Fernandez et al., 2005). Four beaked whales were
found stranded dead over the next three days either on the coast or
floating offshore. These strandings occurred within close proximity of
an international naval exercise that utilized MFAS and involved
numerous surface warships and several submarines. Strandings began
about four hours after the onset of MFAS activity (International
Council for Exploration of the Sea, 2005a; Fernandez et al., 2005).
Eight goose-beaked whales, one Blainville's beaked whale, and one
Gervais' beaked whale were necropsied, 6 of them within 12 hours of
stranding (Fernandez et al., 2005). No pathogenic bacteria were
isolated from the carcasses (Jepson et al., 2003). The animals
displayed severe vascular congestion and hemorrhage especially around
the tissues in the jaw, ears, brain, and kidneys, displaying marked
disseminated microvascular hemorrhages associated with widespread fat
emboli (Jepson et al., 2003; International Council for Exploration of
the Sea, 2005a). Several organs contained intravascular bubbles,
although definitive evidence of gas embolism in vivo is difficult to
determine after death (Jepson et al., 2003). The livers of the
necropsied animals were the most consistently affected organ, which
contained macroscopic gas-filled cavities and had variable degrees of
fibrotic encapsulation. In some animals, cavitary lesions had
extensively replaced the normal tissue (Jepson et al., 2003). Stomachs
contained a large amount of fresh and undigested contents, suggesting a
rapid onset of disease and death (Fernandez et al., 2005). Head and
neck lymph nodes were enlarged and congested, and parasites were found
in the kidneys of all animals (Fernandez et al., 2005).
The association of NATO MFAS use close in space and time to the
beaked whale strandings, and the similarity between this stranding
event and previous beaked whale mass strandings coincident with sonar
use, suggests that a similar scenario and causative mechanism of
stranding may be shared between the events. Beaked whales stranded in
this event demonstrated brain and auditory system injuries,
hemorrhages, and congestion in multiple organs, similar to the
pathological findings of the Bahamas and Madeira stranding events. In
addition, the necropsy results of the Canary Islands stranding event
lead to the hypothesis that the presence of disseminated and widespread
gas bubbles and fat emboli were indicative of nitrogen bubble
formation, similar to what might be expected in decompression sickness
(Jepson et al., 2003; Fern[aacute]ndez et al., 2005).
Hanalei Bay (2004)--
On July 3 and 4, 2004, approximately 150 to 200 melon-headed whales
occupied the shallow waters of Hanalei Bay, Kaua'i, Hawaii for over 28
hours. Attendees of a canoe blessing observed the animals entering the
Bay in a single wave formation at 7 a.m. on July 3, 2004. The animals
were observed moving back into the shore from the mouth of the Bay at 9
a.m. The usually pelagic animals milled in the shallow bay and were
returned to deeper water with human assistance beginning at 9:30 a.m.
on July 4, 2004, and were out of sight by 10:30 a.m.

[[Page 19941]]

Only one animal, a calf, was known to have died following this
event. The animal was noted alive and alone in the Bay on the afternoon
of July 4, 2004, and was found dead in the Bay the morning of July 5,
2004. A full necropsy, magnetic resonance imaging, and computerized
tomography examination were performed on the calf to determine the
manner and cause of death. The combination of imaging, necropsy and
histological analyses found no evidence of infectious, internal
traumatic, congenital, or toxic factors. Cause of death could not be
definitively determined, but it is likely that maternal separation,
poor nutritional condition, and dehydration contributed to the final
demise of the animal. Although it is not known when the calf was
separated from its mother, the animals' movement into the Bay and
subsequent milling and re-grouping may have contributed to the
separation or lack of nursing, especially if the maternal bond was weak
or this was an inexperienced mother with her first calf.
Environmental factors, abiotic and biotic, were analyzed for any
anomalous occurrences that would have contributed to the animals
entering and remaining in Hanalei Bay. The Bay's bathymetry is similar
to many other sites within the Hawaiian Island chain and dissimilar to
sites that have been associated with mass strandings in other parts of
the United States. The weather conditions appeared to be normal for
that time of year with no fronts or other significant features noted.
There was no evidence of unusual distribution, occurrence of predator
or prey species, or unusual harmful algal blooms, although Mobley et
al. (2007) suggested that the full moon cycle that occurred at that
time may have influenced a run of squid into the Bay. Weather patterns
and bathymetry that have been associated with mass strandings elsewhere
were not found to occur in this instance.
The Hanalei event was spatially and temporally correlated with
RIMPAC. Official sonar training and tracking exercises in the Pacific
Missile Range Facility (PMRF) warning area did not commence until
approximately 8 a.m. on July 3 and were thus ruled out as a possible
trigger for the initial movement into the bay. However, six naval
surface vessels transiting to the operational area on July 2
intermittently transmitted active sonar (for approximately 9 hours
total from 1:15 p.m. to 12:30 a.m.) as they approached from the south.
The potential for these transmissions to have triggered the whales'
movement into Hanalei Bay was investigated. Analyses with the
information available indicated that animals to the south and east of
Kaua'i could have detected active sonar transmissions on July 2, and
reached Hanalei Bay on or before 7 a.m. on July 3. However, data
limitations regarding the position of the whales prior to their arrival
in the Bay, the magnitude of sonar exposure, behavioral responses of
melon-headed whales to acoustic stimuli, and other possible relevant
factors preclude a conclusive finding regarding the role of sonar in
triggering this event. Propagation modeling suggests that transmissions
from sonar use during the July 3 exercise in the PMRF warning area may
have been detectable at the mouth of the bay. If the animals responded
negatively to these signals, it may have contributed to their continued
presence in the bay. The U.S. Navy ceased all active sonar
transmissions during exercises in this range on the afternoon of July
3. Subsequent to the cessation of sonar use, the animals were herded
out of the bay.
While causation of this stranding event may never be unequivocally
determined, NMFS considers the active sonar transmissions of July 2-3,
2004, a plausible, if not likely, contributing factor in what may have
been a confluence of events. This conclusion is based on the following:
(1) the evidently anomalous nature of the stranding; (2) its close
spatiotemporal correlation with wide-scale, sustained use of sonar
systems previously associated with stranding of deep-diving marine
mammals; (3) the directed movement of two groups of transmitting
vessels toward the southeast and southwest coast of Kaua'i; (4) the
results of acoustic propagation modeling and an analysis of possible
animal transit times to the bay; and (5) the absence of any other
compelling causative explanation. The initiation and persistence of
this event may have resulted from an interaction of biological and
physical factors. The biological factors may have included the presence
of an apparently uncommon, deep-diving cetacean species (and possibly
an offshore, non-resident group), social interactions among the animals
before or after they entered the bay, and/or unknown predator or prey
conditions. The physical factors may have included the presence of
nearby deep water, multiple vessels transiting in a directed manner
while transmitting active sonar over a sustained period, the presence
of surface sound ducting conditions, and/or intermittent and random
human interactions while the animals were in the bay.
A separate event involving melon-headed whales and rough-toothed
dolphins took place over the same period of time in the Northern
Mariana Islands (Jefferson et al., 2006), which is several thousand
miles from Hawaii. Some 500 to 700 melon-headed whales came into
Sasanhaya Bay on July 4, 2004, near the island of Rota and then left of
their own accord after 5.5 hours; no known active sonar transmissions
occurred in the vicinity of that event. The Rota incident led to
scientific debate regarding what, if any, relationship the event had to
the simultaneous events in Hawaii and whether they might be related by
some common factor (e.g., there was a full moon on July 2, 2004, as
well as during other melon-headed whale strandings and nearshore
aggregations (Brownell et al., 2009; Lignon et al., 2007; Mobley et
al., 2007). Brownell et al. (2009) compared the two incidents, along
with one other stranding incident at Nuka Hiva in French Polynesia and
normal resting behaviors observed at Palmyra Island, in regard to
physical features in the areas, melon-headed whale behavior, and lunar
cycles. Brownell et al., (2009) concluded that the rapid entry of the
whales into Hanalei Bay, their movement into very shallow water far
from the 328-ft (100-m) contour, their milling behavior (typical pre-
stranding behavior), and their reluctance to leave the bay constituted
an unusual event that was not similar to the events that occurred at
Rota, which appear to be similar to observations of melon-headed whales
resting normally at Palmyra Island. Additionally, there was no
correlation between lunar cycle and the types of behaviors observed in
the Brownell et al. (2009) examples.
Spain (2006)--
The Spanish Cetacean Society reported an atypical mass stranding of
four beaked whales that occurred January 26, 2006, on the southeast
coast of Spain, near Moj[aacute]car (Gulf of Vera) in the Western
Mediterranean Sea. According to the report, two of the whales were
discovered the evening of January 26 and were found to be still alive.
Two other whales were discovered during the day on January 27 but had
already died. The first three animals were located near the town of
Moj[aacute]car and the fourth animal was found dead, a few kilometers
north of the first three animals. From January 25-26, 2006, Standing
NATO Response Force Maritime Group Two (five of seven ships including
one U.S. ship under NATO Operational Control) had conducted active
sonar training against a Spanish submarine within 50 nmi (93 km) of the
stranding site.

[[Page 19942]]

Veterinary pathologists necropsied the two male and two female
goose-beaked whales. According to the pathologists, the most likely
primary cause of this type of beaked whale mass stranding event was
anthropogenic acoustic activities, most probably anti-submarine MFAS
used during the military naval exercises. However, no positive acoustic
link was established as a direct cause of the stranding. Even though no
causal link can be made between the stranding event and naval
exercises, certain conditions may have existed in the exercise area
that, in their aggregate, may have contributed to the marine mammal
strandings (Freitas, 2004). Exercises were conducted in areas of at
least 547 fathoms (1,000 m) depth near a shoreline where there is a
rapid change in bathymetry on the order of 547 to 3,281 fathoms (1,000
to 6,000 m) occurring across a relatively short horizontal distance
(Freitas, 2004). Multiple ships (in this instance, five) were operating
MFAS in the same area over extended periods of time (in this case, 20
hours) in close proximity; and exercises took place in an area
surrounded by landmasses, or in an embayment. Exercises involving
multiple ships employing MFAS near land may have produced sound
directed towards a channel or embayment that may have cut off the lines
of egress for the affected marine mammals (Freitas, 2004).
Honaunau Bay (2022)--
On March 25, 2022, a beaked whale (species unknown) stranded in
Honaunau Bay, Hawaii. The animal was observed swimming into shore and
over rocks. Bystanders intervened to turn the animal off of the rocks,
and it swam back out of the Bay on its own. Locals reported hearing a
siren or alarm type of sound underwater on the same day, and a Navy
vessel was observed from shore on the following day. The Navy confirmed
it used CAS within 27 nmi (50 km) and 48 hours of the time of
stranding, though the stranding has not been definitively linked to the
Navy's CAS use.
Behaviorally Mediated Responses to MFAS That May Lead To Stranding
Although the confluence of Navy MFAS with the other contributory
factors noted in the 2001 NMFS/Navy joint report was identified as the
cause of the 2000 Bahamas stranding event, the specific mechanisms that
led to that stranding (or the others) are not well understood, and
there is uncertainty regarding the ordering of effects that led to the
stranding. It is unclear whether beaked whales were directly injured by
sound (e.g., acoustically mediated bubble growth, as addressed above)
prior to stranding or whether a behavioral response to sound occurred
that ultimately caused the beaked whales to be injured and strand.
Although causal relationships between beaked whale stranding events
and active sonar remain unknown, several authors have hypothesized that
stranding events involving these species in the Bahamas and Canary
Islands may have been triggered when the whales changed their dive
behavior in a startled response to exposure to active sonar or to
further avoid exposure (Cox et al., 2006; Rommel et al., 2006). These
authors proposed three mechanisms by which the behavioral responses of
beaked whales upon being exposed to active sonar might result in a
stranding event. These include the following: gas bubble formation
caused by excessively fast surfacing; remaining at the surface too long
when tissues are supersaturated with nitrogen; or diving prematurely
when extended time at the surface is necessary to eliminate excess
nitrogen. More specifically, beaked whales that occur in deep waters
that are in close proximity to shallow waters (for example, the
``canyon areas'' that are cited in the Bahamas stranding event; see
D'Spain and D'Amico, 2006), may respond to active sonar by swimming
into shallow waters to avoid further exposures and strand if they were
not able to swim back to deeper waters. Second, beaked whales exposed
to active sonar might alter their dive behavior. Changes in their dive
behavior might cause them to remain at the surface or at depth for
extended periods of time which could lead to hypoxia directly by
increasing their oxygen demands or indirectly by increasing their
energy expenditures (to remain at depth) and increase their oxygen
demands as a result. If beaked whales are at depth when they detect a
ping from an active sonar transmission and change their dive profile,
this could lead to the formation of significant gas bubbles, which
could damage multiple organs or interfere with normal physiological
function (Cox et al., 2006; Rommel et al., 2006; Zimmer and Tyack,
2007). Baird et al. (2005) found that slow ascent rates from deep dives
and long periods of time spent within 164 ft (50 m) of the surface were
typical for both goose-beaked and Blainville's beaked whales, the two
species involved in mass strandings related to naval sonar. These two
behavioral mechanisms may be necessary to purge excessive dissolved
nitrogen concentrated in their tissues during their frequent long dives
(Baird et al., 2005). Baird et al. (2005) further suggests that
abnormally rapid ascents or premature dives in response to high-
intensity sonar could indirectly result in physical harm to the beaked
whales, through the mechanisms described above (gas bubble formation or
non-elimination of excess nitrogen). In a review of the previously
published data on the potential impacts of sonar on beaked whales,
Bernaldo de Quir[oacute]s et al. (2019) suggested that the effect of
MFAS on beaked whales varies among individuals or populations, and that
predisposing conditions such as previous exposure to sonar and
individual health risk factors may contribute to individual outcomes
(such as decompression sickness).
Because many species of marine mammals make repetitive and
prolonged dives to great depths, it has long been assumed that marine
mammals have evolved physiological mechanisms to protect against the
effects of rapid and repeated decompressions. Although several
investigators have identified physiological adaptations that may
protect marine mammals against nitrogen gas supersaturation (alveolar
collapse and elective circulation; Kooyman et al., 1972; Ridgway and
Howard, 1979), Ridgway and Howard (1979) reported that bottlenose
dolphins that were trained to dive repeatedly had muscle tissues that
were substantially supersaturated with nitrogen gas. Houser et al.
(2001b) used these data to model the accumulation of nitrogen gas
within the muscle tissue of other marine mammal species and concluded
that cetaceans that dive deep and have slow ascent or descent speeds
would have tissues that are more supersaturated with nitrogen gas than
other marine mammals. Based on these data, Cox et al. (2006)
hypothesized that a critical dive sequence might make beaked whales
more prone to stranding in response to acoustic exposures. The sequence
began with (1) very deep (to depths as deep as 1.2 mi (2 km)) and long
(as long as 90 minutes) foraging dives; (2) relatively slow, controlled
ascents; and (3) a series of ``bounce'' dives between 328 and 1,312 ft
(100 and 400 m) in depth (see Zimmer and Tyack, 2007). They concluded
that acoustic exposures that disrupted any part of this dive sequence
(for example, causing beaked whales to spend more time at surface
without the bounce dives that are necessary to recover from the deep
dive) could produce excessive levels of nitrogen supersaturation in
their tissues, leading to gas bubble and emboli

[[Page 19943]]

formation that produces pathologies similar to decompression sickness.
Zimmer and Tyack (2007) modeled nitrogen tension and bubble growth
in several tissue compartments for several hypothetical dive profiles
and concluded that repetitive shallow dives (defined as a dive where
depth does not exceed the depth of alveolar collapse, approximately 236
ft (72 m) for goose-beaked whale), perhaps as a consequence of an
extended avoidance response to sonar sound, could pose a risk for
decompression sickness and that this risk should increase with the
duration of the response. Their models also suggested that
unrealistically rapid rates of ascent from normal dive behaviors are
unlikely to result in supersaturation to the extent that bubble
formation would be expected. Tyack et al. (2006) suggested that emboli
observed in animals exposed to mid-frequency range sonar (Jepson et
al., 2003; Fernandez et al., 2005; Fern[aacute]ndez et al., 2012) could
stem from a behavioral response that involves repeated dives shallower
than the depth of lung collapse. Given that nitrogen gas accumulation
is a passive process (i.e., nitrogen is metabolically inert), a
bottlenose dolphin was trained to repetitively dive a profile predicted
to elevate nitrogen saturation to the point that nitrogen bubble
formation was predicted to occur. However, inspection of the vascular
system of the dolphin via ultrasound did not demonstrate the formation
of asymptomatic nitrogen gas bubbles (Houser et al., 2007). Baird et
al. (2008), in a beaked whale tagging study off Hawaii, showed that
deep dives are equally common during day or night, but ``bounce dives''
are typically a daytime behavior, possibly associated with visual
predator avoidance. This may indicate that ``bounce dives'' are
associated with something other than behavioral regulation of dissolved
nitrogen levels, which would be necessary day and night.
Additional predictive modeling conducted to date has been performed
with many unknowns about the respiratory physiology of deep-diving
breath-hold animals. For example, Denk et al. (2020) found intra-
species differences in the compliance of tracheobronchial structures of
post-mortem cetaceans and pinnipeds under diving hydrostatic pressures,
which would affect depth of alveolar collapse. Although, as
hypothesized by Garcia Parraga et al. (2018) and reviewed in Fahlman et
al., (2021), mechanisms may exist that allow marine mammals to create a
pulmonary shunt without the need for hydrostatic pressure-induced lung
collapse, i.e., by varying perfusion to the lung independent of lung
collapse and degree of ventilation. If such a mechanism exists, then
assumptions in prior gas models require reconsideration, the degree of
nitrogen gas accumulation associated with dive profiles needs to be re-
evaluated, and behavioral responses potentially leading to a
destabilization of the relationship between pulmonary ventilation and
perfusion should be considered. Costidis and Rommel (2016) suggested
that gas exchange may continue to occur across the tissues of air-
filled sinuses in deep diving odontocetes below the depth of lung
collapse if hydrostatic pressures are high enough to drive gas exchange
across into non-capillary veins.
If marine mammals respond to an Action Proponent vessel that is
transmitting active sonar in the same way that they might respond to a
predator, their probability of flight responses could increase when
they perceive that Action Proponent vessels are approaching them
directly, because a direct approach may convey detection and intent to
capture (Burger and Gochfeld, 1981, 1990; Cooper, 1997; Cooper, 1998).
The probability of flight responses could also increase as received
levels of active sonar increase (and the ship is, therefore, closer)
and as ship speeds increase (that is, as approach speeds increase). For
example, the probability of flight responses in Dall's sheep (Ovis
dalli dalli) (Frid 2001a; Frid 2001b), ringed seals (Born et al.,
1999), Pacific brant (Branta bernicla nigricans) and Canada geese (B.
canadensis) increased as a helicopter or fixed-wing aircraft approached
groups of these animals more directly (Ward et al., 1999). Bald eagles
(Haliaeetus leucocephalus) perched on trees alongside a river were also
more likely to flee from a paddle raft when their perches were closer
to the river or were closer to the ground (Steidl and Anthony, 1996).
Despite the many theories involving bubble formation (both as a
direct cause of injury, see Non-Auditory Injury section and an indirect
cause of stranding), Southall et al. (2007) summarizes that there is
either scientific disagreement or a lack of information regarding each
of the following important points: (1) received acoustical exposure
conditions for animals involved in stranding events; (2) pathological
interpretation of observed lesions in stranded marine mammals; (3)
acoustic exposure conditions required to induce such physical trauma
directly; (4) whether noise exposure may cause behavioral responses
(such as atypical diving behavior) that secondarily cause bubble
formation and non-auditory injury; and (5) the extent the post mortem
artifacts introduced by decomposition before sampling, handling,
freezing, or necropsy procedures affect interpretation of observed
lesions.
Strandings Associated With Explosive Use
Silver Strand (2011)--
During a Navy training event on March 4, 2011, at the Silver Strand
Training Complex in San Diego, California, three or possibly four
dolphins were killed in an explosion. During an underwater detonation
training event, a pod of 100 to 150 long-beaked common dolphins were
observed moving towards the 700-yd (640.1-m) exclusion zone around the
explosive charge, monitored by personnel in a safety boat and
participants in a dive boat. Approximately 5 minutes remained on a
time-delay fuse connected to a single 8.76 lb (3.97 kg) explosive
charge (C-4 and detonation cord). Although the dive boat was placed
between the pod and the explosive in an effort to guide the dolphins
away from the area, that effort was unsuccessful and three long-beaked
common dolphins near the explosion died. The Navy recovered those
animals and transferred them to the local stranding network for
necropsy. In addition to the three dolphins found dead on March 4, the
remains of a fourth dolphin were discovered on March 7, 2011, near
Oceanside, California (3 days later and approximately 42 mi (68 km)
north of the detonation), which might also have been related to this
event. Upon necropsy, all four animals were found to have sustained
typical mammalian primary blast injuries (Danil and St Leger, 2011).
Association of the fourth stranding with the training event is
uncertain because dolphins strand on a regular basis in the San Diego
area. Details such as the dolphins' depth and distance from the
explosive at the time of the detonation could not be estimated from the
250 yd (228.6 m) standoff point of the observers in the dive boat or
the safety boat.
These dolphin mortalities are the only known occurrence of a Navy
training or testing event involving impulsive energy (underwater
detonation) that caused mortality or injury to a marine mammal. Despite
this being a rare occurrence, the Navy reviewed training requirements,
safety procedures, and possible mitigation measures and implemented
changes to reduce the potential for this to occur in the future.

[[Page 19944]]

Discussions of procedures associated with underwater explosives
training and other training events are presented in the Proposed
Mitigation Measures section.
Kyle of Durness, Scotland (2011)--
On July 22, 2011, a mass stranding event involving long-finned
pilot whales occurred at Kyle of Durness, Scotland. An investigation by
Brownlow et al. (2015) considered unexploded ordnance detonation
activities at a Ministry of Defense bombing range, conducted by the
Royal Navy prior to and during the strandings, as a plausible
contributing factor in the mass stranding event. While Brownlow et al.
(2015) concluded that the serial detonations of underwater ordnance
were an influential factor in the mass stranding event (along with the
presence of a potentially compromised animal and navigational error in
a topographically complex region), they also suggest that mitigation
measures--which included observations from a zodiac only and by
personnel not experienced in marine mammal observation, among other
deficiencies--were likely insufficient to assess if cetaceans were in
the vicinity of the detonations. The authors also cite information from
the Ministry of Defense indicating ``an extraordinarily high level of
activity'' (i.e., frequency and intensity of underwater explosions) on
the range in the days leading up to the stranding.
Strandings on the Atlantic Coast and the Gulf of America
Stranded marine mammals are reported along the entire Atlantic
Coast and Gulf of America each year. Marine mammals strand due to
natural or anthropogenic causes; the majority of reported type of
occurrences in marine mammal strandings in this region include fishery
interactions, illness, predation, and vessel strikes (Henry et al.,
2024). Stranding events that are associated with active UMEs on the
Atlantic Coast and the Gulf of America (inclusive of the AFTT Study
Area) were previously discussed in the Description of Marine Mammals in
the Area of Specified Activities section.

Potential Effects of Vessel Strike

Vessel strikes of marine mammals can result in death or serious
injury of the animal. Wounds resulting from vessel strike may include
massive trauma, hemorrhaging, broken bones, or propeller lacerations
(Knowlton and Kraus, 2001). An animal at the surface could be struck
directly by a vessel, a surfacing animal could hit the bottom of a
vessel, or an animal just below the surface could be cut by a vessel's
propeller. Superficial strikes may not kill or result in the death of
the animal. Lethal interactions are typically associated with large
whales, which are occasionally found draped across the bulbous bow of
large commercial ships upon arrival in port. Although smaller cetaceans
are more maneuverable in relation to large vessels than are large
whales, they may also be susceptible to strike. The severity of
injuries typically depends on the size and speed of the vessel
(Knowlton and Kraus, 2001; Laist et al., 2001; Vanderlaan and Taggart,
2007; Conn and Silber, 2013). Impact forces increase with speed, as
does the probability of a strike at a given distance (Silber et al.,
2010; Gende et al., 2011).
The most vulnerable marine mammals are those that spend extended
periods of time at the surface in order to restore oxygen levels within
their tissues after deep dives (e.g., the sperm whale; Jaquet &
Whitehead, 1996; Watkins et al., 1999). Additionally, NARW mother-calf
pairs spend 45 to 80 percent of their time surface resting or near-
surface feeding during the first nine months of the calf's life (Cusano
et al., 2019), making them more susceptible to vessel strike. Further,
some baleen whales seem generally unresponsive to vessel sound, making
them more susceptible to vessel strikes (Nowacek et al., 2004). These
species are primarily large, slow-moving whales. Marine mammal
responses to vessels may include avoidance and changes in dive pattern
(NRC, 2003).
Wounds resulting from vessel strike may include massive trauma,
hemorrhaging, broken bones, or propeller lacerations (Knowlton and
Kraus, 2001). An animal at the surface could be struck directly by a
vessel, a surfacing animal could hit the bottom of a vessel, or an
animal just below the surface could be cut by a vessel's propeller.
Impact forces increase with speed as does the probability of a strike
at a given distance (Silber et al., 2010; Gende et al., 2011). An
examination of all known vessel strikes from all shipping sources
(civilian and military) indicates vessel speed is a principal factor in
whether a vessel strike results in death or serious injury (Knowlton
and Kraus, 2001; Laist et al., 2001; Jensen and Silber, 2003; Pace and
Silber, 2005; Vanderlaan and Taggart, 2007). In assessing records in
which vessel speed was known, Laist et al. (2001) found a direct
relationship between the occurrence of a whale strike and the speed of
the vessel involved in the collision. The authors concluded that most
deaths occurred when a vessel was traveling in excess of 13 kn (24 km/
hr).
Jensen and Silber (2003) detailed 292 records of known or probable
vessel strikes of all large whale species from 1975 to 2002. Of these,
vessel speed at the time of collision was reported for 58 cases. Of
these 58 cases, 39 (or 67 percent) resulted in serious injury or death
(19 of those resulted in serious injury as determined by blood in the
water, propeller gashes or severed tailstock, and fractured skull, jaw,
vertebrae, hemorrhaging, massive bruising or other injuries noted
during necropsy and 20 resulted in death). Operating speeds of vessels
that struck various species of large whales ranged from 2 to 51 kn (3.7
to 94.5 km/hr). The majority (79 percent) of these strikes occurred at
speeds of 13 kn (24 km/hr) or greater. The average speed that resulted
in serious injury or death was 18.6 kn (34.4 km/hr). Pace and Silber
(2005) found that the probability of death or serious injury increased
rapidly with increasing vessel speed. Specifically, the predicted
probability of serious injury or death increased from 45 to 75 percent
as vessel speed increased from 10 to 14 kn (18.5 to 25.9 km/hr), and
exceeded 90 percent at 17 kn (31.5 km/hr). Higher speeds during strikes
result in greater force of impact and also appear to increase the
chance of severe injuries or death. While modeling studies have
suggested that hydrodynamic forces pulling whales toward the vessel
hull increase with increasing speed (Clyne, 1999; Knowlton et al.,
1995), this is inconsistent with Silber et al. (2010), which
demonstrated that there is no such relationship (i.e., hydrodynamic
forces are independent of speed).
In a separate study, Vanderlaan and Taggart (2007) analyzed the
probability of lethal mortality of large whales at a given speed,
showing that the greatest rate of change in the probability of a lethal
injury to a large whale as a function of vessel speed occurs between
8.6 and 15 kn (15.9 and 27.8 km/hr). The chances of a lethal injury
decline from approximately 80 percent at 15 kn to approximately 20
percent at 8.6 kn (15.9 km/hr). At speeds below 11.8 kn (21.9 km/hr),
the chances of lethal injury drop below 50 percent, while the
probability asymptotically increases toward 100 percent above 15 kn
(27.8 km/hr). Garrison et al. (2025) reviewed and updated available
data on whale-vessel interactions in U.S. waters to determine the
effects of vessel speed and size on lethality of strikes of large
whales, and found vessel size class had a significant effect on the
probability of lethality. Decreasing vessel speeds

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reduced the likelihood of a lethal outcome for all vessel size classes
modeled, with the strongest effect for vessels less than 354 ft (108 m)
long. Notably, the probability that a strike by a very large vessel
(length) will be lethal exceeded 0.80 at all speeds greater than 5 kn
(9.26 km/hr) (Garrison et al., 2025).
The Jensen and Silber (2003) report notes that the database
represents a minimum number of strikes, because the vast majority
probably goes undetected or unreported. In contrast, Action Proponent
vessels are likely to detect any strike that does occur because of the
required personnel training and Lookouts (as described in the Proposed
Mitigation Measures section), and they are required to report all
vessel strikes involving marine mammals.
In the AFTT Study Area, commercial traffic is heaviest in the
nearshore waters, near major ports and in the shipping lanes along the
entire U.S. East Coast and along the northern coast of the Gulf of
America, while military vessel traffic is primarily concentrated
between the mouth of the Chesapeake Bay and Jacksonville, Florida
(Mintz, 2016). An examination of vessel traffic within the AFTT Study
Area determined that military vessel occurrence is two orders of
magnitude lower than that of commercial traffic. The study also
revealed that while commercial traffic is relatively steady throughout
the year, military vessel usage within the range complexes is episodic,
based on specific exercises being conducted at different times of the
year (Mintz, 2012); however, military vessel use within inshore waters
occurs regularly and routinely consists of high-speed small craft
movements. Juvenile whales of some species may be particularly
vulnerable to vessel strikes due to their particular habitat use and
surface foraging behavior in nearshore waters, where smaller vessel
numbers are higher (Stepanuk et al., 2021).
Over a period of 18 years from 1995 to 2012 there were a total of
19 Navy vessel strikes in the AFTT Study Area. Eight of the strikes
resulted in a confirmed death; but in 11 of the 19 strikes, the fate of
the animal was unknown. It is possible that some of the 11 reported
strikes resulted in recoverable injury or were not marine mammals at
all, but another large marine species (e.g., basking shark). However,
it is prudent to consider that all of the strikes could have resulted
in the death of a marine mammal. From 2009 to 2024, there have been a
total of three whale strikes by the U.S. Navy (one in 2011, two in
2012), and three whale strikes by the U.S. Coast Guard (two in 2009,
one in 2024) reported in the AFTT Study Area. In the 2009 Coast Guard
strike of two whales, the whales were observed swimming away with no
apparent injuries. All known strikes of large whales by the U.S. Navy
and the U.S. Coast Guard in the AFTT Study Area have been in the
VACAPES Operating Area. In 2021, a small Navy vessel struck a dolphin
in Saint Andrew's Pass, Florida (offshore Panama City, Florida).
Between 2007 and 2009, the Navy developed and distributed
additional training, mitigation, and reporting tools to Navy operators
to improve marine mammal protection and to ensure compliance with
permit requirements. In 2009, the Navy implemented Marine Species
Awareness Training designed to improve effectiveness of visual
observation for marine mammals and other marine resources. In
subsequent years, the Navy issued refined policy guidance on vessel
strikes in order to collect the most accurate and detailed data
possible in response to a possible incident (also see the Notification
and Reporting Plan for this proposed rule). For over a decade, the Navy
has implemented the Protective Measures Assessment Protocol software
tool, which provides operators with notification of the required
mitigation and a visual display of the planned training or testing
activity location overlaid with relevant environmental data.

Marine Mammal Habitat

The proposed training and testing activities could potentially
affect marine mammal habitat through the introduction of impacts to the
prey species of marine mammals, acoustic habitat (sound in the water
column), water quality, and biologically important habitat for marine
mammals. Each of these potential effects was considered in the 2024
AFTT Draft Supplemental EIS/OEIS and was determined not to have adverse
effects on marine mammal habitat. Based on the information below and
the supporting information included in the 2024 AFTT Draft Supplemental
EIS/OEIS, NMFS has determined that the proposed training and training
activities would not have adverse or long-term impacts on marine mammal
habitat.
Effects to Prey
Sound may affect marine mammals through impacts on the abundance,
behavior, or distribution of prey species (e.g., crustaceans,
cephalopods, fish, zooplankton). Marine mammal prey varies by species,
season, and location and, for some species, is not well-documented.
Here, we describe studies regarding the effects of noise on known
marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009).
The most likely effects on fishes exposed to loud, intermittent, low-
frequency sounds are behavioral responses (i.e., flight or avoidance).
Short duration, sharp sounds (such as pile driving or air guns) can
cause overt or subtle changes in fish behavior and local distribution.
The response of fish to acoustic sources depends on the physiological
state of the fish, past exposures, motivation (e.g., feeding, spawning,
migration), and other environmental factors. Key impacts to fishes may
include behavioral responses, hearing damage, barotrauma (pressure-
related injuries), and mortality. While it is clear that the behavioral
responses of individual prey, such as displacement or other changes in
distribution, can have direct impacts on the foraging success of marine
mammals, the effects on marine mammals of individual prey that
experience hearing damage, barotrauma, or mortality is less clear,
though obviously population scale impacts that meaningfully reduce the
amount of prey available could have more serious impacts.
Fishes, like other vertebrates, have a variety of different sensory
systems to glean information from ocean around them (Astrup and Mohl,
1993; Astrup, 1999; Braun and Grande, 2008; Carroll et al., 2017;
Hawkins and Johnstone, 1978; Ladich and Popper, 2004; Ladich and
Schulz-Mirbach, 2016; Mann, 2016; Nedwell et al., 2004; Popper et al.,
2003; Popper et al., 2005). Depending on their hearing anatomy and
peripheral sensory structures, which vary among species, fishes hear
sounds using pressure and particle motion sensitivity capabilities and
detect the motion of surrounding water (Fay et al., 2008) (terrestrial
vertebrates generally only detect pressure). Most marine fishes
primarily detect particle motion using the inner ear and lateral line
system, while some fishes possess additional morphological adaptations
or specializations that can enhance their sensitivity to sound
pressure, such as a gas-filled swim bladder (Braun and Grande, 2008;
Popper and Fay, 2011). Hearing capabilities vary considerably between
different fish species with data only available for just over 100
species out of the 34,000 marine and freshwater fish species (Eschmeyer
and Fong, 2016). In order to better understand acoustic

[[Page 19946]]

impacts on fishes, fish hearing groups are defined by species that
possess a similar continuum of anatomical features which result in
varying degrees of hearing sensitivity (Popper and Hastings, 2009a).
There are four hearing groups defined for all fish species (modified
from Popper et al., 2014) within this analysis and they include: fishes
without a swim bladder (e.g., flatfish, sharks, rays, etc.); fishes
with a swim bladder not involved in hearing (e.g., salmon, cod,
pollock, etc.); fishes with a swim bladder involved in hearing (e.g.,
sardines, anchovy, herring, etc.); and fishes with a swim bladder
involved in hearing and high-frequency hearing (e.g., shad and
menhaden). Most marine mammal fish prey species would not be likely to
perceive or hear mid- or high-frequency sonars. While hearing studies
have not been done on sardines and northern anchovies, it would not be
unexpected for them to possess hearing similarities to Pacific herring
(up to 2-5 kHz) (Mann et al., 2005). Currently, less data are available
to estimate the range of best sensitivity for fishes without a swim
bladder.
In terms of physiology, multiple scientific studies have documented
a lack of mortality or physiological effects to fish from exposure to
low- and mid-frequency sonar and other sounds (Halvorsen et al., 2012;
J[oslash]rgensen et al., 2005; Juanes et al., 2017; Kane et al., 2010;
Kvadsheim and Sevaldsen, 2005; Popper et al., 2007; Popper et al.,
2016; Watwood et al., 2016). Techer et al. (2017) exposed carp in
floating cages for up to 30 days to low-power 23 and 46 kHz sources
without any significant physiological response. Other studies have
documented either a lack of TTS in species whose hearing range cannot
perceive military sonar, or for those species that could perceive
sonar-like signals, any TTS experienced would be recoverable (Halvorsen
et al., 2012; Ladich and Fay, 2013; Popper and Hastings, 2009a, 2009b;
Popper et al., 2014; Smith, 2016). Only fishes that have
specializations that enable them to hear sounds above about 2,500 Hz
(2.5 kHz) such as herring (Halvorsen et al., 2012; Mann et al., 2005;
Mann, 2016; Popper et al., 2014) would have the potential to receive
TTS or exhibit behavioral responses from exposure to mid-frequency
sonar. In addition, any sonar induced TTS to fish whose hearing range
could perceive sonar would only occur in the narrow spectrum of the
source (e.g., 3.5 kHz) compared to the fish's total hearing range
(e.g., 0.01 kHz to 5 kHz). Overall, military sonar sources are much
narrower in terms of source frequency compared to a given fish species
full hearing range (Halvorsen et al., 2012; J[oslash]rgensen et al.,
2005; Juanes et al., 2017; Kane et al., 2010; Kvadsheim & Sevaldsen,
2005; Popper et al., 2007; Popper and Hawkins, 2016; Watwood et al.,
2016).
In terms of behavioral responses, Juanes et al. (2017) discuss the
potential for negative impacts from anthropogenic soundscapes on fish,
but the author's focus was on broader based sounds such as ship and
boat noise sources. Watwood et al. (2016) also documented no behavioral
responses by reef fish after exposure to MFAS. Doksaeter et al. (2009;
2012) reported no behavioral responses to mid-frequency military sonar
by Atlantic herring; specifically, no escape responses (vertically or
horizontally) were observed in free swimming herring exposed to mid-
frequency sonar transmissions. Based on these results (Doksaeter et
al., 2009; Doksaeter et al., 2012; Sivle et al., 2012), Sivle et al.
(2014) created a model in order to report on the possible population-
level effects on Atlantic herring from active naval sonar. The authors
concluded that the use of military sonar poses little risk to
populations of herring regardless of season, even when the herring
populations are aggregated and directly exposed to sonar. Finally,
Bruintjes et al. (2016) commented that fish exposed to any short-term
noise within their hearing range might initially startle, but would
quickly return to normal behavior. Occasional behavioral responses to
intermittent explosions and impulsive sound sources are unlikely to
cause long-term consequences for individual fish or populations. Fish
that experience hearing loss as a result of exposure to explosions and
impulsive sound sources may have a reduced ability to detect relevant
sounds such as predators, prey, or social vocalizations. However, PTS
has not been known to occur in fishes and any hearing loss in fish may
be as temporary as the timeframe required to repair or replace the
sensory cells that were damaged or destroyed (Popper et al., 2005;
Popper et al., 2014; Smith et al., 2006). It is not known if damage to
auditory nerve fibers could occur, and if so, whether fibers would
recover during this process.
It is also possible for fish to be injured or killed by an
explosion in the immediate vicinity of the surface from dropped or
fired ordnance, or near the bottom from shallow water bottom-placed
underwater mine warfare detonations. Physical effects from pressure
waves generated by underwater sounds (e.g., underwater explosions)
could potentially affect fish within proximity of training or testing
activities. SPLs of sufficient strength have been known to cause injury
to fish and fish mortality (summarized in Popper et al., 2014). The
shock wave from an underwater explosion is lethal to fish at close
range, causing massive organ damage and non-auditory injury and
internal bleeding (Keevin and Hempen, 1997). At greater distance from
the detonation point, the extent of mortality or injury depends on a
number of factors including fish size, body shape, orientation, and
species (Keevin and Hempen, 1997; Wright, 1982). At the same distance
from the source, larger fish are generally less susceptible to death or
injury, elongated forms that are round in cross-section are less at
risk than deep-bodied forms, and fish oriented sideways to the blast
suffer the greatest impact (Edds-Walton and Finneran, 2006; O'Keeffe,
1984; O'Keeffe and Young, 1984; Wiley et al., 1981; Yelverton et al.,
1975). Species with gas-filled organs are more susceptible to injury
and mortality than those without them (Gaspin, 1975; Gaspin et al.,
1976; Goertner et al., 1994). Barotrauma injuries have been documented
during controlled exposure to impact pile driving (an impulsive noise
source, as are explosives and air guns) (Halvorsen et al., 2012b;
Casper et al., 2013).
Fish not killed or driven from a location by an explosion might
change their behavior, feeding pattern, or distribution. Changes in
behavior of fish have been observed as a result of sound produced by
explosives, with effect intensified in areas of hard substrate (Wright,
1982). However, Navy explosive use avoids hard substrate to the best
extent practical during underwater detonations, or deep-water surface
detonations. Stunning from pressure waves could also temporarily
immobilize fish, making them more susceptible to predation. The
abundances of various fish (and invertebrates) near the detonation
point for explosives could be altered for a few hours before animals
from surrounding areas repopulate the area. However, these populations
would likely be replenished as waters near the detonation point are
mixed with adjacent waters. Repeated exposure of individual fish to
sounds from underwater explosions is not likely and exposures are
expected to be short-term and localized. Long-term consequences for
fish populations would not be expected. Several studies have
demonstrated that air gun sounds might affect the distribution and
behavior of

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some fishes, potentially impacting foraging opportunities or increasing
energetic costs (e.g., Fewtrell and McCauley, 2012; Pearson et al.,
1992; Skalski et al., 1992; Santulli et al., 1999; Paxton et al.,
2017).
For fishes exposed to military sonar, there would be limited sonar
use spread out in time and space across large offshore areas such that
only small areas are actually ensonified (tens of miles) compared to
the total life history distribution of fish prey species. There would
be no probability for mortality or physical injury from sonar, and for
most species, no or little potential for hearing or behavioral effects,
except to a few select fishes with hearing specializations (e.g.,
herring) that could perceive mid-frequency sonar. Training and testing
exercises involving explosions are dispersed in space and time;
therefore, repeated exposure of individual fishes is unlikely.
Mortality and injury effects to fishes from explosives would be
localized around the area of a given in-water explosion, but only if
individual fish and the explosive (and immediate pressure field) were
co-located at the same time. Fishes deeper in the water column or on
the bottom would not be affected by water surface explosions. Repeated
exposure of individual fish to sound and energy from underwater
explosions is not likely given fish movement patterns, especially
schooling prey species. Most acoustic effects, if any, are expected to
be short-term and localized. Long-term consequences for fish
populations, including key prey species within the AFTT Study Area,
would not be expected.
Vessels and in-water devices do not normally collide with adult
fish, particularly those that are common marine mammal prey, most of
which can detect and avoid them. Exposure of fishes to vessel strike
stressors is limited to those fish groups that are large, slow-moving,
and may occur near the surface, such as ocean sunfish, whale sharks,
basking sharks, and manta rays. With the exception of sturgeon, these
species are distributed widely in offshore portions of the AFTT Study
Area. Any isolated cases of a military vessel striking an individual
could injure that individual, impacting the fitness of an individual
fish. Vessel strikes would not pose a risk to most of the other marine
fish groups, because many fish can detect and avoid vessel movements,
making strikes rare and allowing the fish to return to their normal
behavior after the ship or device passes. As a vessel approaches a
fish, they could have a detectable behavioral or physiological response
(e.g., swimming away and increased heart rate) as the passing vessel
displaces them. However, such responses are not expected to have
lasting effects on the survival, growth, recruitment, or reproduction
of these marine fish groups at the population level and therefore would
not have an impact on marine mammal species as prey items.
In addition to fish, prey sources such as marine invertebrates
could potentially be impacted by sound stressors as a result of the
proposed activities. However, most marine invertebrates' ability to
sense sounds is very limited. In most cases, marine invertebrates would
not respond to impulsive and non-impulsive sounds, although they may
detect and briefly respond to nearby low-frequency sounds. These short-
term responses would likely be inconsequential to invertebrate
populations.
Invertebrates appear to be able to detect sounds (Pumphrey, 1950;
Frings and Frings, 1967) and are most sensitive to low-frequency sounds
(Packard et al., 1990; Budelmann and Williamson, 1994; Lovell et al.,
2005; Mooney et al., 2010). Data on response of invertebrates such as
squid, another marine mammal prey species, to anthropogenic sound is
more limited (de Soto, 2016; Sole et al., 2017b). Data suggest that
cephalopods are capable of sensing the particle motion of sounds and
detect low frequencies up to 1-1.5 kHz, depending on the species, and
so are likely to detect air gun noise (Kaifu et al., 2008; Hu et al.,
2009; Mooney et al., 2010; Samson et al., 2014). Sole et al. (2017b)
reported physiological injuries to cuttlefish in cages placed at-sea
when exposed during a controlled exposure experiment to low-frequency
sources (315 Hz, 139 to 142 dB re 1 [mu]Pa\2\ and 400 Hz, 139 to 141 dB
re 1 [mu]Pa\2\). Fewtrell and McCauley (2012) reported squids
maintained in cages displayed startle responses and behavioral changes
when exposed to seismic air gun sonar (136-162 re 1 [mu]Pa\2\s).
However, the sources Sole et al. (2017a) and Fewtrell and McCauley
(2012) used are not similar and were much lower than typical military
sources within the AFTT Study Area. Nor do the studies address the
issue of individual displacement outside of a zone of impact when
exposed to sound. Jones et al. (2020) found that when squid
(Doryteuthis (Amerigo) pealeii) were exposed to impulse pile driving
noise, body pattern changes, inking, jetting, and startle responses
were observed and nearly all squid exhibited at least one response.
However, these responses occurred primarily during the first eight
impulses and diminished quickly, indicating potential rapid, short-term
habituation.
Cephalopods have a specialized sensory organ inside the head called
a statocyst that may help an animal determine its position in space
(orientation) and maintain balance (Budelmann, 1992). Packard et al.
(1990) showed that cephalopods were sensitive to particle motion, not
sound pressure, and Mooney et al. (2010) demonstrated that squid
statocysts act as an accelerometer through which particle motion of the
sound field can be detected. Auditory injuries (lesions occurring on
the statocyst sensory hair cells) have been reported upon controlled
exposure to low-frequency sounds, suggesting that cephalopods are
particularly sensitive to low-frequency sound (Andre et al., 2011; Sole
et al., 2013). Behavioral responses, such as inking and jetting, have
also been reported upon exposure to low-frequency sound (McCauley et
al., 2000b; Samson et al., 2014). Squids, like most fish species, are
likely more sensitive to low frequency sounds, and may not perceive
mid- and high-frequency sonars such as military sonars. Cumulatively
for squid as a prey species, individual and population impacts from
exposure to military sonar and explosives, like fish, are not likely to
be significant, and explosive impacts would be short-term and
localized.
Explosions and pile driving would likely kill or injure nearby
marine invertebrates. Vessels also have the potential to impact marine
invertebrates by disturbing the water column or sediments, or directly
striking organisms (Bishop, 2008). The propeller wash (water displaced
by propellers used for propulsion) from vessel movement and water
displaced from vessel hulls can potentially disturb marine
invertebrates in the water column and is a likely cause of zooplankton
mortality (Bickel et al., 2011). The localized and short-term exposure
to explosions or vessels could displace, injure, or kill zooplankton,
invertebrate eggs or larvae, and macro-invertebrates. However,
mortality or long-term consequences for a few animals is unlikely to
have measurable effects on overall populations. Long-term consequences
to marine invertebrate populations would not be expected as a result of
exposure to sounds of vessels in the AFTT Study Area. Impacts to
benthic communities from impulsive sound generated by active acoustic
sound sources are not well documented. (e.g., Andriguetto-Filho et al.,
2005; Payne et al., 2007; 2008; Boudreau et al., 2009). There are no
published data that indicate whether

[[Page 19948]]

temporary or permanent threshold shifts, auditory masking, or
behavioral effects occur in benthic invertebrates (Hawkins et al.,
2014) and some studies showed no short-term or long-term effects of air
gun exposure (e.g., Andriguetto-Filho et al., 2005; Payne et al., 2007;
2008; Boudreau et al., 2009). Exposure to air gun signals was found to
significantly increase mortality in scallops, in addition to causing
significant changes in behavioral patterns during exposure (Day et al.,
2017). However, the authors state that the observed levels of mortality
were not beyond naturally occurring rates. Explosions and pile driving
could potentially kill or injure nearby marine invertebrates; however,
mortality or long-term consequences for a few animals is unlikely to
have measurable effects on overall populations.
There is little information concerning potential impacts of noise
on zooplankton populations. However, one study (McCauley et al., 2017)
investigated zooplankton abundance, diversity, and mortality before and
after exposure to air gun noise, finding that the mortality rate for
zooplankton after air gun exposure was two to three times more compared
with controls for all taxa. The majority of taxa present were copepods
and cladocerans; for these taxa, the range within which effects on
abundance were detected was up to approximately 0.75 mi (1.2 km). In
order to have significant impacts on r-selected species (species that
produce a large number of offspring and contribute few resources to
each individual offspring) such as plankton, the spatial or temporal
scale of impact must be large in comparison with the ecosystem
concerned (McCauley et al., 2017).
Notably, a recently described study produced results inconsistent
with those of McCauley et al. (2017). Researchers conducted a field and
laboratory study to assess if exposure to air gun noise affects
mortality, predator escape response, or gene expression of the copepod
Calanus finmarchicus (Fields et al., 2019). Immediate mortality of
copepods was significantly higher, relative to controls, at distances
of 16.4 ft (5 m) or less from the air guns. Mortality one week after
the air gun blast was significantly higher in the copepods placed 32.8
ft (10 m) from the air gun but was not significantly different from the
controls at a distance of 65.6 ft (20 m) from the air gun. The increase
in mortality, relative to controls, did not exceed 30 percent at any
distance from the air gun. Moreover, the authors caution that even this
higher mortality in the immediate vicinity of the air guns may be more
pronounced than what would be observed in free-swimming animals due to
increased flow speed of fluid inside bags containing the experimental
animals. There were no sublethal effects on the escape performance or
the sensory threshold needed to initiate an escape response at any of
the distances from the air gun that were tested. Whereas McCauley et
al. (2017) reported an SEL of 156 dB at a range of 1,670-2,158.8 ft
(509-658 m), with zooplankton mortality observed at that range, Fields
et al. (2019) reported an SEL of 186 dB at a range of 82 ft (25 m),
with no reported mortality at that distance. The large scale of effect
observed here is of concern--particularly where repeated noise exposure
is expected--and further study is warranted.
Military expended materials resulting from training and testing
activities could potentially result in minor long-term changes to
benthic habitat, however the impacts of small amounts of expended
materials are unlikely to have measurable effects on overall
populations. Military expended materials may be colonized over time by
benthic organisms that prefer hard substrate and would provide
structure that could attract some species of fish or invertebrates.
Overall, the combined impacts of sound exposure, explosions, vessel
strikes, and military expended materials resulting from the proposed
activities would not be expected to have measurable effects on
populations of marine mammal prey species. Prey species exposed to
sound might move away from the sound source, experience TTS, experience
masking of biologically relevant sounds, or show no obvious direct
effects. Mortality from decompression injuries is possible in close
proximity to a sound, but only limited data on mortality in response to
air gun noise exposure are available (Fields et al., 2019, Hawkins et
al., 2014, McCauley et al., 2017). The most likely impacts for most
prey species in a given area would be temporary avoidance of the area.
Surveys using towed air gun arrays move through an area relatively
quickly, limiting exposure to multiple impulsive sounds. In all cases,
sound levels would return to ambient once a survey ends and the noise
source is shut down and, when exposure to sound ends, behavioral and/or
physiological responses are expected to end relatively quickly
(McCauley et al., 2000b). The duration of fish avoidance of a given
area after survey effort stops is unknown, but a rapid return to normal
recruitment, distribution, and behavior is anticipated. While the
potential for disruption of spawning aggregations or schools of
important prey species can be meaningful on a local scale, the mobile
and temporary nature of most surveys and the likelihood of temporary
avoidance behavior suggest that impacts would be minor. Long-term
consequences to marine invertebrate populations would not be expected
as a result of exposure to sounds or vessels in the AFTT Study Area.
Acoustic Habitat
Acoustic habitat is the soundscape which encompasses all of the
sound present in a particular location and time, as a whole when
considered from the perspective of the animals experiencing it. Animals
produce sound for, or listen for sounds produced by, conspecifics
(communication during feeding, mating, and other social activities),
other animals (finding prey or avoiding predators), and the physical
environment (finding suitable habitats, navigating). Together, sounds
made by animals and the geophysical environment (e.g., produced by
earthquakes, lightning, wind, rain, waves) make up the natural
contributions to the total acoustics of a place. These acoustic
conditions, termed acoustic habitat, are one attribute of an animal's
total habitat.
Soundscapes are also defined by, and acoustic habitat influenced
by, the total contribution of anthropogenic sound. This may include
incidental emissions from sources such as vessel traffic or may be
intentionally introduced to the marine environment for data acquisition
purposes (as in the use of air gun arrays) or for military training and
testing purposes (as in the use of sonar and explosives and other
acoustic sources). Anthropogenic noise varies widely in its frequency,
content, duration, and loudness, and these characteristics greatly
influence the potential habitat-mediated effects to marine mammals
(please also see the previous discussion in the Masking section), which
may range from local effects for brief periods of time to chronic
effects over large areas and for long durations. Depending on the
extent of effects to habitat, animals may alter their communications
signals (thereby potentially expending additional energy) or miss
acoustic cues (either conspecific or adventitious). Problems arising
from a failure to detect cues are more likely to occur when noise
stimuli are chronic and overlap with biologically relevant cues used
for communication, orientation, and predator/prey detection (Francis
and Barber, 2013). For more detail on these concepts see, e.g., Barber
et al., 2009; Pijanowski et al., 2011; Francis and Barber, 2013; Lillis
et al., 2014.

[[Page 19949]]

The term ``listening area'' refers to the region of ocean over
which sources of sound can be detected by an animal at the center of
the space. Loss of communication space concerns the area over which a
specific animal signal (used to communicate with conspecifics in
biologically important contexts such as foraging or mating) can be
heard, in noisier relative to quieter conditions (Clark et al., 2009).
Lost listening area concerns the more generalized contraction of the
range over which animals would be able to detect a variety of signals
of biological importance, including eavesdropping on predators and prey
(Barber et al., 2009). Such metrics do not, in and of themselves,
document fitness consequences for the marine animals that live in
chronically noisy environments. Long-term population-level consequences
mediated through changes in the ultimate survival and reproductive
success of individuals are difficult to study, and particularly so
underwater. However, it is increasingly well documented that aquatic
species rely on qualities of natural acoustic habitats, with
researchers quantifying reduced detection of important ecological cues
(e.g., Francis and Barber, 2013; Slabbekoorn et al., 2010) as well as
survivorship consequences in several species (e.g., Simpson et al.,
2014; Nedelec et al., 2015).
The sounds produced during training and testing activities can be
widely dispersed or concentrated in small areas for varying periods.
Sound produced from training and testing activities in the AFTT Study
Area is temporary and transitory. Any anthropogenic noise attributed to
training and testing activities in the AFTT Study Area would be
temporary and the affected area would be expected to immediately return
to the original state when these activities cease.
Water Quality
Training and testing activities may introduce water quality
constituents into the water column. Based on the analysis of the 2024
AFTT Draft Supplemental EIS/OEIS, military expended materials (e.g.,
undetonated explosive materials) would be released in quantities and at
rates that would not result in a violation of any water quality
standard or criteria. NMFS has reviewed this analysis and concurs that
it reflects the best available science. High-order explosions consume
most of the explosive material, creating typical combustion products.
For example, in the case of Royal Demolition Explosive, 98 percent of
the products are common seawater constituents and the remainder is
rapidly diluted below threshold effect level. Explosion by-products
associated with high order detonations present no secondary stressors
to marine mammals through sediment or water. However, low order
detonations and unexploded ordnance present elevated likelihood of
impacts on marine mammals.
Indirect effects of explosives and unexploded ordnance to marine
mammals via sediment is possible in the immediate vicinity of the
ordnance. Degradation products of Royal Demolition Explosive are not
toxic to marine organisms at realistic exposure levels (Rosen and
Lotufo, 2010). Relatively low solubility of most explosives and their
degradation products means that concentrations of these contaminants in
the marine environment are relatively low and readily diluted.
Furthermore, while explosives and their degradation products were
detectable in marine sediment approximately 6-12 inches (0.15-0.3 m)
away from degrading ordnance, the concentrations of these compounds
were not statistically distinguishable from background beyond 3-6 ft
(1-2 m) from the degrading ordnance. Taken together, it is possible
that marine mammals could be exposed to degrading explosives, but it
would be within a very small radius of the explosive (1-6 ft (0.3-2
m)).
Equipment used by the Action Proponents within the AFTT Study Area,
including ships and other marine vessels, aircraft, and other
equipment, are also potential sources of by-products. All equipment is
properly maintained in accordance with applicable Navy, Coast Guard and
legal requirements. All such operating equipment meets Federal water
quality standards, where applicable.

Estimated Take of Marine Mammals

This section indicates the number of takes that NMFS is proposing
to authorize, which is based on the amount of take that NMFS
anticipates is reasonably likely to occur. NMFS coordinated closely
with the Action Proponents in the development of their incidental take
application, and preliminarily agrees that the methods the Action
Proponents have put forth described herein to estimate take (including
the model, thresholds, and density estimates), and the resulting
numbers are based on the best available science and appropriate for
authorization.
Takes would be predominantly in the form of harassment, but a small
number of mortalities are also possible. For this military readiness
activity, the MMPA defines ``harassment'' as (i) Any act that injures
or has the significant potential to injure a marine mammal or marine
mammal stock in the wild (Level A harassment); or (ii) Any act that
disturbs or is likely to disturb a marine mammal or marine mammal stock
in the wild by causing disruption of natural behavioral patterns,
including, but not limited to, migration, surfacing, nursing, breeding,
feeding, or sheltering, to a point where the behavioral patterns are
abandoned or significantly altered (Level B harassment).
Proposed authorized takes would primarily be in the form of Level B
harassment, as use of the acoustic (e.g., active sonar, pile driving,
and seismic air guns) and explosive sources is most likely to result in
disruption of natural behavioral patterns to a point where they are
abandoned or significantly altered (as defined specifically at the
beginning of this section, but referred to generally as behavioral
disturbance) for marine mammals, either via direct behavioral
disturbance or TTS. There is also the potential for Level A harassment,
in the form of auditory injury to result from exposure to the sound
sources utilized in military readiness activities. Lastly, no more than
6 serious injuries or mortalities total (over the 7-year period) of
large whales could potentially occur through vessel strikes, and 13
serious injuries or mortalities (over the 7-year period) from explosive
use. Although we analyze the impacts of these potential serious
injuries or mortalities that are proposed for authorization, the
proposed mitigation and monitoring measures are expected to minimize
the likelihood (i.e., further lower the already low probability) that
vessel strike (and the associated serious injury or mortality) would
occur, as well as the severity of other takes.
Generally speaking, for acoustic impacts NMFS estimates the amount
and type of harassment by considering: (1) acoustic thresholds above
which NMFS believes the best available science indicates marine mammals
would experience behavioral disturbance or incur some degree of
temporary or permanent hearing impairment; (2) the area or volume of
water that would be ensonified above these levels in a day or event;
(3) the density or occurrence of marine mammals within these ensonified
areas; and (4) the number of days of activities or events.

Acoustic Thresholds

Using the best available science, NMFS, in coordination with the
Navy, has established acoustic thresholds that identify the most
appropriate received

[[Page 19950]]

level of underwater sound above which marine mammals exposed to these
sound sources could be reasonably expected to directly incur a
disruption in behavior patterns to a point where they are abandoned or
significantly altered (equated to onset of Level B harassment), or to
incur TTS onset (equated to Level B harassment via the indirect
disruptions of behavioral patterns) or AUD INJ onset (equated to Level
A harassment). Thresholds have also been developed to identify the
pressure and impulse levels above which animals may incur non-auditory
injury or mortality from exposure to explosive detonation.
Hearing Impairment (TTS/AUD INJ), Non-Auditory Injury, and Mortality
NMFS' 2024 Technical Guidance (NMFS, 2024) identifies dual criteria
to assess AUD INJ (Level A harassment) to five different marine mammal
groups (based on hearing sensitivity) as a result of exposure to noise
from two different types of sources (impulsive or non-impulsive). The
Updated Technical Guidance also identifies criteria to predict TTS,
which is not considered injury and falls into the Level B harassment
category. The Action Proponents' specified activities include the use
of non-impulsive (sonar, vibratory pile driving) and impulsive
(explosives, air guns, impact pile driving) sources.
For the consideration of impacts on hearing in Phase IV, marine
mammals were divided into nine groups for analysis: very low-frequency
cetaceans (VLF), low-frequency cetaceans (LF), high-frequency cetaceans
(HF), very high-frequency cetaceans (VHF), sirenians (SI), phocid
carnivores in water and in air (PCW and PCA, respectively), and
otariids and other non-phocid marine carnivores in water and air (OCW
and OCA, respectively). For each group, a frequency-dependent weighting
function and numeric thresholds for the onset of TTS and the onset of
AUD INJ were estimated. The onset of TTS is defined as a TTS of 6 dB
measured approximately 2-5 minutes after exposure. A TTS of 40 dB is
used as a proxy for the onset of AUD INJ; i.e., it is assumed that
exposures beyond those capable of causing 40 dB of TTS have the
potential to result in PTS or other auditory injury (e.g., loss of
cochlear neuron synapses). Exposures just sufficient to cause TTS or
AUD INJ are denoted as ``TTS onset'' or ``AUD INJ onset'' exposures.
Onset levels are treated as step functions or ``all-or-nothing''
thresholds: exposures above the TTS or AUD INJ onset level are assumed
to always result in TTS or AUD INJ, while exposures below the TTS or
AUD INJ onset level are assumed to not cause TTS or AUD INJ. For non-
impulsive exposures, onset levels are specified in frequency-weighted
sound exposure level (SEL); for impulsive exposures, dual metrics of
weighted SEL and unweighted peak sound pressure level (SPL) are used.
To compare Phase IV weighting functions and TTS/AUD INJ SEL
thresholds to those used in Phase III, both the weighting function
shape and the weighted threshold values were considered; the weighted
thresholds by themselves only indicate the TTS/AUD INJ threshold at the
most susceptible frequency (based on the relevant weighting function).
In contrast, the TTS/AUD INJ exposure functions incorporate both the
shape of the weighting function and the weighted threshold value and
provide the best means of comparing the frequency-dependent TTS/AUD INJ
thresholds for Phase III and Phase IV.
The most significant differences between the Phase III and Phase IV
functions and thresholds include the following:
(1) Mysticetes were divided into two groups (VLF and LF), with the
upper hearing limit for the LF group increased from Phase III to match
recent hearing measurements in minke whales (Houser et al., 2024);
(2) Group names were changed from Phase III to be consistent with
Southall et al. (2019). Specifically, the Phase III mid-frequency (MF)
cetacean group is now designated as the high-frequency (HF) cetacean
group, and the group previously designated as high-frequency (HF)
cetaceans is now the very-high frequency (VHF) cetacean group;
(3) For the HF group, Phase IV onset TTS/AUD INJ thresholds are
lower compared to Phase III at frequencies below approximately 10 kHz.
This is a result of new TTS onset data for dolphins at low frequencies
(Finneran et al., 2023);
(4) For the PCW group, new TTS data for harbor seals (Kastelein et
al., 2020b; Kastelein et al., 2020e) resulted in slightly lower TTS/AUD
INJ thresholds at high frequencies compared to Phase III; and
(5) For group OCW, new TTS data for California sea lions (Kastelein
et al., 2021b; Kastelein et al., 2022a, 2022b) resulted in
significantly lower TTS/AUD INJ thresholds compared to Phase III.
Of note, the thresholds and weighting function for the LF cetacean
hearing group in NMFS' 2024 Technical Guidance (NMFS, 2024) match the
Navy's VLF cetacean hearing group. However, the weighting function for
those hearing groups differs between the two documents (i.e., the
Navy's LF cetacean group has a different weighting function from NMFS)
due to the Houser et al. (2024) minke whale data incorporated into Navy
2024, but not NMFS (2024). While NMFS' 2024 Technical Guidance differs
from the criteria that the Action Proponents used to assess AUD INJ and
TTS for low-frequency cetaceans, NMFS concurs that the criteria the
Action Proponents applied are appropriate for assessing the impacts of
their proposed action. The criteria used by the Action Proponents are
conservative in that those criteria show greater sensitivity at higher
frequencies (i.e., application of those criteria result in a higher
amount of estimated take by higher frequency sonars than would result
from application of NMFS' 2024 Technical Guidance) which is where more
of the take is expected.
These thresholds (table 17 and table 18) were developed by
compiling and synthesizing the best available science and soliciting
input multiple times from both public and peer reviewers. The
references, analysis, and methodology used in the development of the
thresholds are described in Updated Technical Guidance, which may be
accessed at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

Table 17--Acoustic Thresholds Identifying the Onset of TTS and AUD INJ
for Non-Impulsive Sound Sources by Functional Hearing Group
------------------------------------------------------------------------
AUD INJ
Group TTS threshold threshold SEL
SEL (weighted) (weighted)
------------------------------------------------------------------------
Very low-frequency (VLF)............ 177 197
Low-frequency (LF).................. 177 197

[[Page 19951]]

High-frequency (HF)................. 181 201
Very high-frequency (VHF)........... 161 181
Otariid carnivores in water (OW).... 179 199
Phocid carnivores in water (PW)..... 175 195
------------------------------------------------------------------------
Note: SEL thresholds in dB re 1 [mu]Pa\2\s underwater.

Based on the best available science, the Action Proponents (in
coordination with NMFS) used the acoustic and pressure thresholds
indicated in table 17 to predict the onset of behavioral harassment,
AUD INJ, TTS, non-auditory injury, and mortality due to explosive
sources.
For explosive activities using single detonations (i.e., no more
than one detonation within a day), such as those described in the
proposed activity, NMFS uses TTS onset thresholds to assess the
likelihood of behavioral harassment, rather than the Level B harassment
threshold for multiple detonations indicated in table 18. While marine
mammals may also respond to single explosive detonations, these
responses are expected to more typically be in the form of startle
response, rather than a more meaningful disruption of a behavioral
pattern. On the rare occasion that a single detonation might result in
a behavioral response that qualifies as Level B harassment, it would be
expected to be in response to a comparatively higher received level.
Accordingly, NMFS considers the potential for these responses to be
quantitatively accounted for through the application of the TTS
criteria, which, as noted above, is 5 dB higher than the behavioral
harassment threshold for multiple explosives.

Table 18--Explosive Thresholds for Marine Mammals for AUD INJ, TTS, and Behavior
[Multiple detonations]
----------------------------------------------------------------------------------------------------------------
AUD INJ impulsive TTS impulsive threshold Behavioral threshold
Hearing group threshold * * (multiple detonations)
----------------------------------------------------------------------------------------------------------------
Very Low-Frequency (VLF)/Low- Cell 1: Lpk,flat: 222 Cell 2: Lpk,flat: 216 Cell 3: LE,LF,24h: 163
Frequency (LF) Cetaceans. dB; LE,LF,24h: 183 dB. dB LE,LF,24h: 168 dB. dB.
High-Frequency (HF) Cetaceans........ Cell 4: Lpk,flat: 230 Cell 5: Lpk,flat: 224 Cell 6: LE,HF,24h: 173
dB LE,HF,24h: 193 dB. dB LE,HF,24h: 178 dB. dB.
Very High-Frequency (VHF) Cetaceans.. Cell 7: Lpk,flat: 202 Cell 8: Lpk,flat: 196 Cell 9: LE,VHF,24h: 139
dB LE,VHF,24h: 159 dB. dB LE,VHF,24h: 144 dB. dB.
Phocid Pinnipeds (PW) (Underwater)... Cell 10: Lpk,flat: 223 Cell 11: Lpk,flat: 217 Cell 12: LE,PW,24h: 163
dB LE,PW,24h: 183 dB. dB LE,PW,24h: 168 dB. dB.
Otariid Pinnipeds (OW) (Underwater).. Cell 13: Lpk,flat: 230 Cell 14: Lpk,flat: 224 Cell 15: LE,OW,24h: 165
dB LE,OW,24h: 185 dB. dB LE,OW,24h: 170 dB. dB.
----------------------------------------------------------------------------------------------------------------
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
exposure level (LE,p) has a reference value of 1 [micro]Pa\2\s. In this Table, criteria are abbreviated to be
more reflective of International Organization for Standardization standards (ISO, 2017; ISO, 2020). The
subscript ``flat'' is being included to indicate peak sound pressure are flat weighted or unweighted within
the generalized hearing range of marine mammals underwater (i.e., 7 Hz to 165 kHz). The subscript associated
with cumulative sound exposure level criteria indicates the designated marine mammal auditory weighting
function (LF, HF, and VHF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is
24 hours. The weighted cumulative sound exposure level criteria could be exceeded in a multitude of ways
(i.e., varying exposure levels and durations, duty cycle). When possible, it is valuable for action proponents
to indicate the conditions under which these criteria will be exceeded.
* Dual metric criteria for impulsive sounds: Use whichever criteria results in the larger isopleth for
calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure
level criteria associated with impulsive sounds, the PK SPL criteria are recommended for consideration for non-
impulsive sources.

The criterion for mortality is based on severe lung injury observed
in terrestrial mammals exposed to underwater explosions as recorded in
Goertner (1982). The criteria for non-auditory injury are based on
slight lung injury or gastrointestinal (G.I.) tract injury observed in
the same data set. Mortality and slight lung injury impacts to marine
mammals are estimated using impulse thresholds based on both calf/pup/
juvenile and adult masses (see the ``Criteria and Thresholds for U.S.
Navy Acoustic and Explosive Effects Analysis (Phase 4)'' technical
report (U.S. Department of the Navy, 2024)). The peak pressure
threshold applies to all species and age classes. Unlike the prior
analysis (Phase III), this analysis relies on the onset rather than the
mean estimated threshold for these effects. This revision results in a
small increase in the predicted non-auditory injuries and mortalities
for the same event versus prior analyses. Thresholds are provided in
table 19 for use in non-auditory injury assessment for marine mammals
exposed to underwater explosives.

[[Page 19952]]

Table 19--Non-Auditory Injury Thresholds for Underwater Explosives
----------------------------------------------------------------------------------------------------------------
Hearing group Mortality-Impulse * Injury-Impulse * Injury-Peak pressure
----------------------------------------------------------------------------------------------------------------
All Marine Mammals.................. Cell 1: Modified Goertner Cell 2: Modified Cell 3: Lp,0-pk,flat:
model; Equation 1. Goertner model; 237 dB.
Equation 2.
----------------------------------------------------------------------------------------------------------------
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa. In this table, thresholds are abbreviated
to reflect ANSI (2013). However, ANSI defines peak sound pressure as incorporating frequency weighting, which
is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is being included to indicate
peak sound pressure should be flat weighted or unweighted within the overall marine mammal generalized hearing
range.
* Lung injury (severe and slight) thresholds are dependent on animal mass (Recommendation: table C.9 from U.S.
Department of the Navy (2017) based on adult and/or calf/pup mass by species).
Modified Goertner Equations for severe and slight lung injury (pascal-second):

Equation 1: 103M\1/3\(1 + D/10.1)\1/6\ Pa-s
Equation 2: 47.5M\1/3\(1 + D/10.1)\1/6\ Pa-s

M animal (adult and/or calf/pup) mass (kg) (table C.9 in DoN 2017).
D animal depth (meters).

Level B Harassment by Behavioral Disturbance
Though significantly driven by received level and distance, the
onset of Level B harassment by behavioral disturbance from
anthropogenic noise exposure is also informed to varying degrees by
other factors and can be difficult to predict (Southall et al., 2007,
Ellison et al., 2012). As discussed in the Potential Effects of
Specified Activities on Marine Mammals and Their Habitat section,
marine mammal responses to sound (some of which are considered
disturbances that rise to the level of a take) are highly variable and
context specific, i.e., they are affected by differences in acoustic
conditions; differences between species and populations; differences in
gender, age, reproductive status, or social behavior; and other prior
experience of the individuals. This means there is support for
considering alternative approaches for estimating Level B behavioral
harassment. Although the statutory definition of Level B harassment for
military readiness activities means that a natural behavior pattern of
a marine mammal is significantly altered or abandoned, the current
state of science for determining those thresholds is somewhat
unsettled.
Despite the rapidly evolving science, there are still challenges in
quantifying expected behavioral responses that qualify as take by Level
B harassment, especially where the goal is to use one or two
predictable indicators (e.g., received level and distance) to predict
responses that are also driven by additional factors that cannot be
easily incorporated into the thresholds (e.g., context). So, while the
criteria that identify Level B harassment by behavioral disturbance
(referred to as ``behavioral harassment thresholds'') have been refined
to better consider the best available science (e.g., incorporating both
received level and distance), they also still have some built-in
factors to address the challenge noted. For example, while duration of
observed responses in the data are now considered in the thresholds,
some of the responses that are informing take thresholds are of a very
short duration, such that it is possible some of these responses might
not always rise to the level of disrupting behavior patterns to a point
where they are abandoned or significantly altered. We describe the
application of this behavioral harassment threshold as identifying the
maximum number of instances in which marine mammals could be reasonably
expected to experience a disruption in behavior patterns to a point
where they are abandoned or significantly altered. In summary, we
believe these behavioral harassment criteria are the most appropriate
method for predicting Level B harassment by behavioral disturbance
given the best available science and the associated uncertainty.
Sonar--
In its analysis of impacts associated with sonar acoustic sources
(which was coordinated with NMFS), the Action Proponents used an
updated approach, as described below. Many of the behavioral responses
identified using the Action Proponents' quantitative analysis are most
likely to be of moderate severity as described in the Southall et al.
(2021) behavioral response severity scale. These ``moderate'' severity
responses were considered significant if they were sustained for the
duration of the exposure or longer. Within the Action Proponents'
quantitative analysis, many responses are predicted from exposure to
sound that may exceed an animal's Level B behavioral harassment
threshold for only a single exposure (a few seconds) to several
minutes, and it is likely that some of the resulting estimated
behavioral responses that are counted as Level B harassment would not
constitute ``significantly altering or abandoning natural behavioral
patterns,'' i.e., the estimated number of takes by Level B harassment
due to behavioral disturbance and response is likely somewhat of an
overestimate.
As noted above, the Action Proponents coordinated with NMFS to
develop behavioral harassment thresholds specific to their military
readiness activities utilizing active sonar that identify at what
received level and distance Level B harassment by behavioral
disturbance would be expected to result. These behavioral harassment
thresholds consist of behavioral response functions (BRFs) and
associated distance cut-off conditions, and are also referred to,
together, as ``the criteria.'' These criteria are used to estimate the
number of animals that may exhibit a behavioral response that rises to
the level of a take when exposed to sonar and other transducers. The
way the criteria were derived is discussed in detail in the ``Criteria
and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis
(Phase 4)'' technical report (U.S. Department of the Navy, 2024).
Developing these behavioral harassment criteria involved multiple
steps. All peer-reviewed published behavioral response studies
conducted both in the field and on captive animals were examined in
order to understand the breadth of behavioral responses of marine
mammals to sonar and other transducers. Marine mammals were divided
into four groups for analysis: mysticetes (all baleen whales),
odontocetes (most toothed whales, dolphins, and porpoises), sensitive
species (beaked whales and harbor porpoise), and pinnipeds (true seals,
sea lions, walruses, sea otters, polar bears). These groups are like
the groups used in the behavioral response analysis (Phase III), with
the exception of combining beaked whales and harbor porpoise into a
single curve. For each group, a biphasic BRF was developed using the

[[Page 19953]]

best available data and Bayesian dose response models developed at the
University of St. Andrews. The BRF base probability of response on the
highest SPL (rms) received level.
The analysis of BRFs differs from the previous phase (Phase III)
due to the addition of new data and the separation of some species
groups. The Sensitive Species BRF is more sensitive at lower received
levels but less sensitive at higher received levels than the prior
beaked whale and harbor porpoise functions. The Odontocete BRF is less
sensitive across all received levels due to including additional
behavioral response research, which will result in a lower number of
behavioral responses than in the prior analysis for the same event, but
also reduces the avoidance of auditory effects. The Pinnipeds (in-
water) BRF is more sensitive due to the inclusion of additional captive
pinniped data (only three behavioral studies using captive pinnipeds
were available for the derivation of the BRF). Behavioral studies of
captive animals can be difficult to extrapolate to wild animals due to
several factors (e.g., use of trained subjects). This means the
pinniped BRF likely overestimates effects compared to observed
responses of wild pinnipeds to sound and anthropogenic activity. The
Mysticete BRF is less sensitive across most received levels due to
including additional behavioral response research. This will result in
a lower number of behavioral responses than in the prior analysis for
the same event, but also reduces the avoidance of auditory effects.
The BRFs only relate the highest received level of sound to the
probability that an animal will have a behavioral response. The BRFs do
not account for the duration or pattern of use of any individual sound
source or of the activity as a whole; the number of sound sources that
may be operating simultaneously; or how loud the animal may perceive
the sonar signal to be based on the frequency of the sonar versus the
animal's hearing range.
Criteria for assessing marine mammal behavioral responses to sonars
use the metric of highest received sound level (rms) to evaluate the
risk of immediate responses by exposed animals. Currently, there are
limited data to develop criteria that include the context of an
exposure, characteristics of individual animals, behavioral state,
duration of an exposure, sound source duty cycle, and the number of
individual sources in an activity (although these factors certainly
influence the severity of a behavioral response) and, further, even
where certain contextual factors may be predictive where known, it is
difficult to reliably predict when such factors will be present.
The BRFs also do not account for distance. At moderate to low
received levels the correlation between probability of response and
received level is very poor and it appears that other variables mediate
behavioral responses (e.g., Ellison et al., 2011) such as the distance
between the animal and the sound source. For this analysis, distance
between the animal and the sound source (i.e., range) was initially
included, however, range was too confounded with received level and
therefore did not provide additional information about the possibility
of response.
Data suggest that beyond a certain distance, significant behavioral
responses are unlikely. At shorter ranges (less than 10 km) some
behavioral responses have been observed at received levels below 140 dB
re 1 [mu]Pa. Thus, proximity may mediate behavioral responses at lower
received levels. Since most data used to derive the BRFs are within 10
km of the source, probability of response at farther ranges is not
well-represented. Therefore, the source-receiver range must be
considered separately to estimate likely significant behavioral
responses.
This analysis applies behavioral cut-off conditions to responses
predicted using the BRFs. Animals within a specified distance and above
a minimum probability of response are assumed to have a significant
behavioral response. The cut-off distance is based on the farthest
source-animal distance across all known studies where animals exhibited
a significant behavioral response. Animals beyond the cut-off distance
but with received levels above the sound pressure level associated with
a probability of response of 0.50 on the BRF are also assumed to have a
significant behavioral response. The actual likelihood of significant
behavioral responses occurring beyond the distance cut-off is unknown.
Significant behavioral responses beyond 100 km are unlikely based on
source-animal distance and attenuated received levels. The behavioral
cut-off conditions and additional information on the derivation of the
cut-off conditions can be found in table 2.2-3 of the ``Criteria and
Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase
4)'' technical report (U.S. Department of the Navy, 2024).
The Action Proponents used cutoff distances beyond which the
potential of significant behavioral responses (and therefore Level B
harassment) is considered to be unlikely (see table 20). These
distances were determined by examining all available published field
observations of behavioral responses to sonar or sonar-like signals
that included the distance between the sound source and the marine
mammal. Behavioral effects calculations are based on the maximum SPL to
which a modeled marine mammal is exposed. There is empirical evidence
to suggest that animals are more likely to exhibit significant
behavioral responses to moderate levels sounds that are closer and less
likely to exhibit behavioral responses when exposed to moderate levels
of sound from a source that is far away. To account for this, the
Action Proponents have implemented behavioral cutoffs that consider
both received sound level and distance from the source. These updated
cutoffs conditions are unique to each behavioral hearing group, and are
outlined in table 20.

Table 20--Behavioral Cut-Off Conditions for Each Behavioral Hearing
Group
------------------------------------------------------------------------
Received level
associated with
p(0.50) on the
Behavioral group behavioral Cut-off range (km)
response function
(dB rms)
------------------------------------------------------------------------
Sensitive Species............. 133.............. 40
Odontocetes................... 168.............. 15
Mysticetes.................... 185.............. 10
Pinnipeds..................... 156.............. 5
------------------------------------------------------------------------
Note: Sensitive Species includes beaked whales and harbor porpoises.

[[Page 19954]]

The Action Proponents and NMFS have used the best available science
to address the challenging differentiation between significant and non-
significant behavioral responses (i.e., whether the behavior has been
abandoned or significantly altered such that it qualifies as
harassment), but have erred on the cautious side where uncertainty
exists (e.g., counting these lower duration responses as take), which
likely results in some degree of overestimation of Level B harassment
by behavioral disturbance. We consider application of these behavioral
harassment thresholds, therefore, as identifying the maximum number of
instances in which marine mammals could be reasonably expected to
experience a disruption in behavior patterns to a point where they are
abandoned or significantly altered (i.e., Level B harassment). NMFS has
carefully reviewed the criteria (i.e., BRFs and cutoff distances for
the species), and agrees that it is the best available science and is
the appropriate method to use at this time for determining impacts to
marine mammals from military sonar and other transducers and for
calculating take and to support the determinations made in this
proposed rule. Because this is the most appropriate method for
estimating Level B harassment given the best available science and
uncertainty on the topic, it is these numbers of Level B harassment by
behavioral disturbance that are analyzed in the Preliminary Analysis
and Negligible Impact Determination section and would be authorized.
Air Guns, Pile Driving, and Explosives--
Based on what the available science indicates and the practical
need to use a threshold based on a factor that is both predictable and
measurable for most activities, NMFS uses generalized acoustic
thresholds based on received level to estimate the onset of behavioral
harassment for sources other than active sonar. NMFS predicts that
marine mammals are likely to be behaviorally harassed in a manner we
consider Level B harassment when exposed to underwater anthropogenic
noise above received levels of 120 dB re 1 [mu]Pa (rms) for continuous
(e.g., vibratory pile-driving, drilling) and above 160 dB re 1 [mu]Pa
(rms) for non-explosive impulsive (e.g., seismic air guns) or
intermittent (e.g., scientific sonar) sources. For the Action
Proponents' activities, to estimate behavioral effects from air guns,
the threshold of 160 dB re 1 [micro]Pa (rms) is used and the root mean
square calculation for air guns is based on the duration defined by 90
percent of the cumulative energy in the impulse. The indicated
thresholds were also applied to estimate behavioral effects from impact
and vibratory pile driving (table 21). These thresholds are the same as
those applied in the prior analysis (Phase III) of these stressors in
the Study Area, although the explosive behavioral threshold has
shifted, corresponding to changes in the TTS thresholds.

Table 21--Behavioral Response Thresholds for Air Gun, Pile Driving, and
Explosives
------------------------------------------------------------------------
Sound source Behavioral threshold
------------------------------------------------------------------------
Air gun........................... 160 dB rms re 1 [mu]Pa SPL.
Impact pile driving............... 160 dB rms re 1 [mu]Pa SPL.
Vibratory pile driving............ 120 dB rms re 1 [mu]Pa SPL.
Single explosion.................. TTS onset threshold (weighted SEL).
Multiple explosions............... 5 dB less than the TTS onset
threshold (weighted SEL).
------------------------------------------------------------------------

While the best available science for assessing behavioral responses
of marine mammals to impulsive sounds relies on data from seismic and
pile driving sources, it is likely that these predicted responses using
a threshold based on seismic and pile driving represent a worst-case
scenario compared to behavioral responses to explosives used in
military readiness activities, which would typically consist of single
impulses or a cluster of impulses rather than long-duration, repeated
impulses (e.g., large-scale air gun arrays).
For single explosions at received sound levels below hearing loss
thresholds, the most likely behavioral response is a brief alerting or
orienting response. Since no further sounds follow the initial brief
impulses, significant behavioral responses would not be expected to
occur. If a significant response were to occur, the Action Proponents'
analysis assumes it would be as a result of an exposure at levels
within the range of auditory impacts (TTS and AUD INJ). Because of this
approach, the number of auditory impacts is higher than the number of
behavioral impacts in the quantified results for some stocks.
If more than one explosive event occurs within any given 24-hour
period during a military readiness activity, behavioral disturbance is
considered more likely to occur and specific criteria are applied to
predict the number of animals that may have a behavioral response. For
events with multiple explosions, the behavioral threshold used in this
analysis is 5 dB less than the TTS onset threshold. This value is
derived from observed onsets of behavioral response by test subjects
(bottlenose dolphins) during non-impulse TTS testing (Schlundt et al.,
2000).

Navy Acoustic Effects Model

The Navy Acoustic Effects Model (NAEMO) is their standard model for
assessing acoustic effects on marine mammals. NAEMO calculates sound
energy propagation from sonar and other transducers, air guns, and
explosives during military readiness activities and the sound received
by animat dosimeters. Animat dosimeters are virtual representations of
marine mammals distributed in the area around the modeled activity and
each dosimeter records its individual sound ``dose.'' The model bases
the distribution of animats over the AFTT Study Area on the density
values in the Navy Marine Species Density Database (NMSDD) and
distributes animats in the water column proportional to the known time
that species spend at varying depths.
The model accounts for environmental variability of sound
propagation in both distance and depth when computing the sound level
received by the animats. The model conducts a statistical analysis
based on multiple model runs to compute the estimated effects on
animals. The number of animats that exceed the thresholds for effects
is tallied to provide an estimate of the number of marine mammals that
could be affected.
Assumptions in NAEMO intentionally err on the side of
overestimation when there are unknowns. The specified activities are
modeled as though they would occur regardless of proximity to marine
mammals, meaning that the implementation of power downs or shut downs
are not modeled or, thereby,

[[Page 19955]]

considered in the take estimates. For more information on this process,
see the discussion in the Estimated Take from Acoustic Stressors
section below. Many explosions from ordnance such as bombs and missiles
actually occur upon impact with above-water targets. However, for this
analysis, sources such as these were modeled as exploding underwater.
This overestimates the amount of explosive and acoustic energy entering
the water.
The model estimates the acoustic impacts caused by sonars and other
transducers, explosives, and air guns during individual military
readiness exercises. During any individual modeled event, impacts to
individual animats are considered over 24-hour periods. The animats do
not represent actual animals, but rather they represent a distribution
of animals based on density and abundance data, which allows for a
statistical analysis of the number of instances that marine mammals may
be exposed to sound levels resulting in an effect. Therefore, the model
estimates the number of instances in which an effect threshold was
exceeded over the course of a year, but does not estimate the number of
individual marine mammals that may be impacted over a year (i.e., some
marine mammals could be impacted several times, while others would not
experience any impact). A detailed explanation of the Navy's Acoustic
Effects Model is provided in the technical report ``Quantifying
Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and
Analytical Approach for Phase IV Training and Testing'' (U.S.
Department of the Navy, 2024).
As NAEMO interrogates the simulation data in the Animat Processor,
exposures that are both outside the distance cutoff and below the
received level cutoff are omitted when determining the maximum SPL for
each animat. This differs from Phase III, in which only distance
cutoffs were applied, meaning that all exposures outside the distance
cutoffs were omitted, with no consideration of received level.
The presence of the two cutoff criteria in Phase IV provides a more
accurate and conservative estimation of behavioral effects because
louder exposures that would have been omitted previously, when only a
distance cutoff was applied, are considered in Phase IV, while the
estimation of behavioral effects still omits exposures at distances and
received levels that would be unlikely to produce a significant
behavioral response. NAEMO retains the capability of calculating
behavioral effects without the cutoffs applied, depending on user
preference.
The impulsive behavioral criteria are not based on the probability
of a behavioral response but rather on a single SPL metric. For
consideration of impulsive behavioral effects, the cutoff conditions in
table 20 are not applied.

Pile Driving

The Action Proponents performed a quantitative analysis without
NAEMO to estimate the number of times marine mammals could be affected
by pile driving and extraction used during proposed training
activities. The analysis considered details of the activity, sound
exposure criteria, and the number and distribution of marine mammals.
This information was then used in an ``area*density'' model in which
the areas within each footprint (i.e., harassment zone) that
encompassed a potential effect were calculated for a given day's
activities. The effects analyzed included behavioral response, TTS, and
AUD INJ for marine mammals.
Then, these areas were multiplied by the density of each marine
species within the nearshore environment to estimate the number of
effects. Uniform density values for species expected to be present in
the nearshore areas where pile driving could occur were estimated using
the NMSDD or available survey data specific to the activity location.
More detail is provided in the 2024 AFTT Draft Supplemental EIS/OEIS.
Since the same animal can be ``taken'' every day (i.e., 24-hour reset
time), the number of predicted effects from a given day were multiplied
by the number of days for that activity. This generated a total
estimated number of effects over the entire activity, which was then
multiplied by the maximum number of times per year this activity could
happen. The result was the estimated effects per species and stock in a
year.

Range to Effects

This section provides range (distance) to effects for sonar and
other active acoustic sources as well as explosives to specific
acoustic thresholds determined using NAEMO. Ranges are determined by
modeling the distance that noise from a source will need to propagate
to reach exposure level thresholds specific to a hearing group that
will cause behavioral response, TTS, AUD INJ, non-auditory injury, and
mortality. Ranges to effects (tables 22 through 42) are utilized to
help predict impacts from acoustic and explosive sources and assess the
benefit of mitigation zones. Marine mammals exposed within these ranges
for the shown duration are predicted to experience the associated
effect. Range to effects is important information in not only
predicting acoustic impacts, but also in verifying the accuracy of
model results against real-world situations and determining adequate
mitigation ranges to avoid higher level effects, especially
physiological effects to marine mammals.

Sonar

Ranges to effects for sonar were determined by modeling the
distance that sound would need to propagate to reach exposure level
thresholds specific to a hearing group that would cause behavioral
response, TTS, and AUD INJ, as described in the ``Criteria and
Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase
4)'' technical report (U.S. Department of the Navy, 2024). The ranges
do not account for an animal avoiding a source nor for the movement of
the platform, both of which would influence the actual range to onset
of auditory effects during an actual exposure.
Table 22 through table 26 below provide the ranges to TTS and AUD
INJ for marine mammals from exposure durations of 1, 30, 60, and 120
seconds for six sonar systems proposed for use (see also appendix A of
the application). Due to the lower acoustic thresholds for TTS versus
AUD INJ, ranges to TTS are larger. Successive pings can be expected to
add together, further increasing the range to the onset of TTS and AUD
INJ.

Table 22--Very Low-Frequency Cetacean Ranges to Effects for Sonar
----------------------------------------------------------------------------------------------------------------
Duration
Sonar type Depth (m) (s) Range to TTS Range to AUD INJ
----------------------------------------------------------------------------------------------------------------
Dipping Sonar............... <=200 1 160 m (34 m)............... 12 m (6 m).
Dipping Sonar............... <=200 30 330 m (70 m)............... 21 m (10 m).
Dipping Sonar............... <=200 60 460 m (98 m)............... 25 m (10 m).
Dipping Sonar............... <=200 120 700 m (145 m).............. 35 m (8 m).

[[Page 19956]]

Dipping Sonar............... >200 1 140 m (42 m)............... 0 m (1 m).
Dipping Sonar............... >200 30 250 m (81 m)............... 0 m (8 m).
Dipping Sonar............... >200 60 330 m (115 m).............. 18 m (11 m).
Dipping Sonar............... >200 120 499 m (172 m).............. 35 m (15 m).
MF1 Ship Sonar.............. <=200 1 1,528 m (635 m)............ 90 m (10 m).
MF1 Ship Sonar.............. <=200 30 1,528 m (635 m)............ 90 m (10 m).
MF1 Ship Sonar.............. <=200 60 2,514 m (1,176 m).......... 140 m (19 m).
MF1 Ship Sonar.............. <=200 120 3,264 m (1,592 m).......... 180 m (27 m).
MF1 Ship Sonar.............. >200 1 1,000 m (449 m)............ 85 m (3 m).
MF1 Ship Sonar.............. >200 30 1,000 m (449 m)............ 85 m (3 m).
MF1 Ship Sonar.............. >200 60 1,750 m (804 m)............ 130 m (6 m).
MF1 Ship Sonar.............. >200 120 2,250 m (1,143 m).......... 170 m (9 m).
MF1C Ship Sonar............. <=200 1 1,542 m (637 m)............ 90 m (10 m).
MF1C Ship Sonar............. <=200 30 3,306 m (1,596 m).......... 180 m (27 m).
MF1C Ship Sonar............. <=200 60 4,917 m (2,648 m).......... 273 m (51 m).
MF1C Ship Sonar............. <=200 120 6,944 m (4,219 m).......... 447 m (92 m).
MF1C Ship Sonar............. >200 1 1,000 m (460 m)............ 85 m (3 m).
MF1C Ship Sonar............. >200 30 2,250 m (1,162 m).......... 170 m (9 m).
MF1C Ship Sonar............. >200 60 4,278 m (1,747 m).......... 250 m (15 m).
MF1C Ship Sonar............. >200 120 5,750 m (2,558 m).......... 370 m (37 m).
MF1K Ship Sonar............. <=200 1 200 m (27 m)............... 13 m (2 m).
MF1K Ship Sonar............. <=200 30 412 m (77 m)............... 24 m (1 m).
MF1K Ship Sonar............. <=200 60 575 m (106 m).............. 30 m (1 m).
MF1K Ship Sonar............. <=200 120 885 m (191 m).............. 45 m (3 m).
MF1K Ship Sonar............. >200 1 190 m (7 m)................ 11 m (6 m).
MF1K Ship Sonar............. >200 30 340 m (18 m)............... 23 m (11 m).
MF1K Ship Sonar............. >200 60 440 m (31 m)............... 30 m (2 m).
MF1K Ship Sonar............. >200 120 625 m (58 m)............... 40 m (2 m).
Mine-Hunting Sonar.......... <=200 1 3 m (2 m).................. 0 m (0 m).
Mine-Hunting Sonar.......... <=200 30 6 m (3 m).................. 0 m (0 m).
Mine-Hunting Sonar.......... <=200 60 9 m (5 m).................. 0 m (0 m).
Mine-Hunting Sonar.......... <=200 120 13 m (7 m)................. 1 m (0 m).
Mine-Hunting Sonar.......... >200 1 0 m (0 m).................. 0 m (0 m).
Mine-Hunting Sonar.......... >200 30 5 m (2 m).................. 0 m (0 m).
Mine-Hunting Sonar.......... >200 60 8 m (4 m).................. 0 m (0 m).
Mine-Hunting Sonar.......... >200 120 12 m (6 m)................. 0 m (0 m).
Sonobuoy Sonar.............. <=200 1 13 m (7 m)................. 0 m (0 m).
Sonobuoy Sonar.............. <=200 30 25 m (11 m)................ 0 m (0 m).
Sonobuoy Sonar.............. <=200 60 35 m (15 m)................ 0 m (1 m).
Sonobuoy Sonar.............. <=200 120 50 m (16 m)................ 0 m (2 m).
Sonobuoy Sonar.............. >200 1 0 m (7 m).................. 0 m (0 m).
Sonobuoy Sonar.............. >200 30 23 m (12 m)................ 0 m (0 m).
Sonobuoy Sonar.............. >200 60 35 m (17 m)................ 0 m (0 m).
Sonobuoy Sonar.............. >200 120 50 m (20 m)................ 0 m (0 m).
----------------------------------------------------------------------------------------------------------------
Note: Median ranges are shown with standard deviation ranges in parentheses. The Action Proponents split the LF
functional hearing group into LF and VLF based on Houser et al., (2024), however, NMFS updated acoustic
technical guidance (NMFS, 2024) does not include these data but we have included the VLF group here for
reference.

Table 23--Low-Frequency Cetacean Ranges to Effects for Sonar
----------------------------------------------------------------------------------------------------------------
Duration
Sonar type Depth (m) (s) Range to TTS Range to AUD INJ
----------------------------------------------------------------------------------------------------------------
Dipping Sonar............... <=200 1 166 m (63 m)............... 12 m (5 m).
Dipping Sonar............... <=200 30 333 m (109 m).............. 21 m (7 m).
Dipping Sonar............... <=200 60 465 m (138 m).............. 25 m (8 m).
Dipping Sonar............... <=200 120 701 m (154 m).............. 35 m (12 m).
Dipping Sonar............... >200 1 140 m (78 m)............... 0 m (6 m).
Dipping Sonar............... >200 30 220 m (120 m).............. 13 m (10 m).
Dipping Sonar............... >200 60 280 m (156 m).............. 24 m (12 m).
Dipping Sonar............... >200 120 440 m (110 m).............. 35 m (18 m).
MF1 Ship Sonar.............. <=200 1 1,653 m (658 m)............ 95 m (10 m).
MF1 Ship Sonar.............. <=200 30 1,653 m (658 m)............ 95 m (10 m).
MF1 Ship Sonar.............. <=200 60 2,653 m (1,213 m).......... 140 m (20 m).
MF1 Ship Sonar.............. <=200 120 3,486 m (1,632 m).......... 180 m (27 m).
MF1 Ship Sonar.............. >200 1 1,042 m (498 m)............ 90 m (4 m).
MF1 Ship Sonar.............. >200 30 1,042 m (498 m)............ 90 m (4 m).
MF1 Ship Sonar.............. >200 60 1,819 m (863 m)............ 140 m (5 m).
MF1 Ship Sonar.............. >200 120 2,694 m (1,210 m).......... 180 m (8 m).
MF1C Ship Sonar............. <=200 1 1,653 m (660 m)............ 93 m (10 m).

[[Page 19957]]

MF1C Ship Sonar............. <=200 30 3,528 m (1,637 m).......... 180 m (27 m).
MF1C Ship Sonar............. <=200 60 5,208 m (2,724 m).......... 286 m (52 m).
MF1C Ship Sonar............. <=200 120 7,458 m (4,345 m).......... 461 m (95 m).
MF1C Ship Sonar............. >200 1 1,056 m (511 m)............ 90 m (4 m).
MF1C Ship Sonar............. >200 30 2,708 m (1,231 m).......... 180 m (8 m).
MF1C Ship Sonar............. >200 60 4,514 m (1,834 m).......... 260 m (16 m).
MF1C Ship Sonar............. >200 120 6,167 m (2,656 m).......... 380 m (41 m).
MF1K Ship Sonar............. <=200 1 200 m (28 m)............... 14 m (1 m).
MF1K Ship Sonar............. <=200 30 429 m (80 m)............... 25 m (0 m).
MF1K Ship Sonar............. <=200 60 596 m (112 m).............. 30 m (1 m).
MF1K Ship Sonar............. <=200 120 915 m (203 m).............. 45 m (3 m).
MF1K Ship Sonar............. >200 1 190 m (6 m)................ 14 m (1 m).
MF1K Ship Sonar............. >200 30 350 m (14 m)............... 24 m (1 m).
MF1K Ship Sonar............. >200 60 450 m (33 m)............... 30 m (0 m).
MF1K Ship Sonar............. >200 120 650 m (72 m)............... 45 m (0 m).
Mine-Hunting Sonar.......... <=200 1 9 m (5 m).................. 0 m (0 m).
Mine-Hunting Sonar.......... <=200 30 18 m (9 m)................. 1 m (1 m).
Mine-Hunting Sonar.......... <=200 60 25 m (11 m)................ 2 m (1 m).
Mine-Hunting Sonar.......... <=200 120 35 m (14 m)................ 3 m (2 m).
Mine-Hunting Sonar.......... >200 1 8 m (4 m).................. 0 m (0 m).
Mine-Hunting Sonar.......... >200 30 17 m (8 m)................. 1 m (0 m).
Mine-Hunting Sonar.......... >200 60 25 m (11 m)................ 2 m (1 m).
Mine-Hunting Sonar.......... >200 120 35 m (10 m)................ 3 m (1 m).
Sonobuoy Sonar.............. <=200 1 12 m (8 m)................. 0 m (0 m).
Sonobuoy Sonar.............. <=200 30 25 m (11 m)................ 0 m (0 m).
Sonobuoy Sonar.............. <=200 60 40 m (16 m)................ 0 m (1 m).
Sonobuoy Sonar.............. <=200 120 55 m (23 m)................ 0 m (1 m).
Sonobuoy Sonar.............. >200 1 0 m (7 m).................. 0 m (0 m).
Sonobuoy Sonar.............. >200 30 20 m (12 m)................ 0 m (0 m).
Sonobuoy Sonar.............. >200 60 35 m (19 m)................ 0 m (0 m).
Sonobuoy Sonar.............. >200 120 55 m (27 m)................ 0 m (0 m).
----------------------------------------------------------------------------------------------------------------
Note: Median ranges are shown with standard deviation ranges in parentheses. The Action Proponents split the LF
functional hearing group into LF and VLF based on Houser et al., (2024), however, NMFS updated acoustic
technical guidance (NMFS, 2024) does not include these data but we have included the VLF group here for
reference.

Table 24--High-Frequency Cetacean Ranges to Effects for Sonar
----------------------------------------------------------------------------------------------------------------
Duration
Sonar type Depth (m) (s) Range to TTS Range to AUD INJ
----------------------------------------------------------------------------------------------------------------
Dipping Sonar............... <=200 1 55 m (18 m)................ 5 m (2 m).
Dipping Sonar............... <=200 30 120 m (42 m)............... 9 m (3 m).
Dipping Sonar............... <=200 60 170 m (60 m)............... 12 m (5 m).
Dipping Sonar............... <=200 120 270 m (90 m)............... 18 m (6 m).
Dipping Sonar............... >200 1 50 m (27 m)................ 0 m (2 m).
Dipping Sonar............... >200 30 100 m (56 m)............... 0 m (4 m).
Dipping Sonar............... >200 60 140 m (77 m)............... 0 m (6 m).
Dipping Sonar............... >200 120 209 m (113 m).............. 0 m (8 m).
MF1 Ship Sonar.............. <=200 1 832 m (189 m).............. 45 m (3 m).
MF1 Ship Sonar.............. <=200 30 832 m (189 m).............. 45 m (3 m).
MF1 Ship Sonar.............. <=200 60 1,208 m (357 m)............ 65 m (6 m).
MF1 Ship Sonar.............. <=200 120 1,500 m (561 m)............ 85 m (9 m).
MF1 Ship Sonar.............. >200 1 600 m (117 m).............. 45 m (11 m).
MF1 Ship Sonar.............. >200 30 600 m (117 m).............. 45 m (11 m).
MF1 Ship Sonar.............. >200 60 892 m (263 m).............. 65 m (13 m).
MF1 Ship Sonar.............. >200 120 1,000 m (421 m)............ 85 m (6 m).
MF1C Ship Sonar............. <=200 1 835 m (189 m).............. 45 m (3 m).
MF1C Ship Sonar............. <=200 30 1,500 m (562 m)............ 85 m (9 m).
MF1C Ship Sonar............. <=200 60 2,514 m (1,075 m).......... 130 m (17 m).
MF1C Ship Sonar............. <=200 120 4,069 m (1,805 m).......... 200 m (30 m).
MF1C Ship Sonar............. >200 1 600 m (120 m).............. 45 m (11 m).
MF1C Ship Sonar............. >200 30 1,000 m (432 m)............ 85 m (6 m).
MF1C Ship Sonar............. >200 60 1,736 m (783 m)............ 130 m (8 m).
MF1C Ship Sonar............. >200 120 3,028 m (1,363 m).......... 200 m (12 m).
MF1K Ship Sonar............. <=200 1 100 m (9 m)................ 7 m (3 m).
MF1K Ship Sonar............. <=200 30 190 m (25 m)............... 13 m (3 m).
MF1K Ship Sonar............. <=200 60 270 m (42 m)............... 17 m (3 m).
MF1K Ship Sonar............. <=200 120 430 m (80 m)............... 25 m (1 m).
MF1K Ship Sonar............. >200 1 100 m (19 m)............... 7 m (3 m).
MF1K Ship Sonar............. >200 30 180 m (11 m)............... 13 m (6 m).

[[Page 19958]]

MF1K Ship Sonar............. >200 60 240 m (11 m)............... 17 m (7 m).
MF1K Ship Sonar............. >200 120 350 m (18 m)............... 25 m (9 m).
Mine-Hunting Sonar.......... <=200 1 8 m (4 m).................. 0 m (0 m).
Mine-Hunting Sonar.......... <=200 30 15 m (6 m)................. 1 m (0 m).
Mine-Hunting Sonar.......... <=200 60 22 m (8 m)................. 1 m (1 m).
Mine-Hunting Sonar.......... <=200 120 30 m (9 m)................. 2 m (1 m).
Mine-Hunting Sonar.......... >200 1 7 m (3 m).................. 0 m (0 m).
Mine-Hunting Sonar.......... >200 30 15 m (5 m)................. 0 m (0 m).
Mine-Hunting Sonar.......... >200 60 21 m (7 m)................. 0 m (1 m).
Mine-Hunting Sonar.......... >200 120 25 m (6 m)................. 0 m (1 m).
Sonobuoy Sonar.............. <=200 1 8 m (4 m).................. 0 m (0 m).
Sonobuoy Sonar.............. <=200 30 18 m (8 m)................. 0 m (0 m).
Sonobuoy Sonar.............. <=200 60 25 m (12 m)................ 0 m (0 m).
Sonobuoy Sonar.............. <=200 120 35 m (13 m)................ 0 m (1 m).
Sonobuoy Sonar.............. >200 1 0 m (4 m).................. 0 m (0 m).
Sonobuoy Sonar.............. >200 30 0 m (9 m).................. 0 m (0 m).
Sonobuoy Sonar.............. >200 60 0 m (12 m)................. 0 m (0 m).
Sonobuoy Sonar.............. >200 120 25 m (16 m)................ 0 m (1 m).
----------------------------------------------------------------------------------------------------------------
Note: Median ranges are shown with standard deviation ranges in parentheses.

Table 25--Very High-Frequency Cetacean Ranges to Effects for Sonar
----------------------------------------------------------------------------------------------------------------
Duration
Sonar type Depth (m) (s) Range to TTS Range to AUD INJ
----------------------------------------------------------------------------------------------------------------
Dipping Sonar............... <=200 1 100 m (37 m)............... 8 m (3 m).
Dipping Sonar............... <=200 30 210 m (79 m)............... 14 m (5 m).
Dipping Sonar............... <=200 60 291 m (97 m)............... 19 m (6 m).
Dipping Sonar............... <=200 120 454 m (104 m).............. 25 m (8 m).
Dipping Sonar............... >200 1 95 m (49 m)................ 0 m (3 m).
Dipping Sonar............... >200 30 180 m (98 m)............... 0 m (6 m).
Dipping Sonar............... >200 60 230 m (125 m).............. 14 m (8 m).
Dipping Sonar............... >200 120 310 m (75 m)............... 24 m (12 m).
MF1 Ship Sonar.............. <=200 1 2,750 m (1,203 m).......... 150 m (19 m).
MF1 Ship Sonar.............. <=200 30 2,750 m (1,203 m).......... 150 m (19 m).
MF1 Ship Sonar.............. <=200 60 4,347 m (2,022 m).......... 230 m (36 m).
MF1 Ship Sonar.............. <=200 120 5,306 m (2,709 m).......... 293 m (51 m).
MF1 Ship Sonar.............. >200 1 1,806 m (867 m)............ 150 m (6 m).
MF1 Ship Sonar.............. >200 30 1,806 m (867 m)............ 150 m (6 m).
MF1 Ship Sonar.............. >200 60 3,569 m (1,420 m).......... 220 m (12 m).
MF1 Ship Sonar.............. >200 120 4,500 m (1,761 m).......... 270 m (15 m).
MF1C Ship Sonar............. <=200 1 2,778 m (1,206 m).......... 150 m (19 m).
MF1C Ship Sonar............. <=200 30 5,472 m (2,717 m).......... 295 m (51 m).
MF1C Ship Sonar............. <=200 60 7,861 m (4,337 m).......... 480 m (94 m).
MF1C Ship Sonar............. <=200 120 10,896 m (6,387 m)......... 750 m (163 m).
MF1C Ship Sonar............. >200 1 1,806 m (892 m)............ 150 m (6 m).
MF1C Ship Sonar............. >200 30 4,514 m (1,802 m).......... 270 m (16 m).
MF1C Ship Sonar............. >200 60 6,139 m (2,607 m).......... 390 m (42 m).
MF1C Ship Sonar............. >200 120 8,403 m (3,750 m).......... 550 m (95 m).
MF1K Ship Sonar............. <=200 1 350 m (61 m)............... 20 m (1 m).
MF1K Ship Sonar............. <=200 30 724 m (139 m).............. 35 m (1 m).
MF1K Ship Sonar............. <=200 60 976 m (222 m).............. 50 m (3 m).
MF1K Ship Sonar............. <=200 120 1,306 m (456 m)............ 85 m (6 m).
MF1K Ship Sonar............. >200 1 300 m (9 m)................ 16 m (3 m).
MF1K Ship Sonar............. >200 30 525 m (46 m)............... 35 m (0 m).
MF1K Ship Sonar............. >200 60 700 m (78 m)............... 50 m (2 m).
MF1K Ship Sonar............. >200 120 1,000 m (138 m)............ 85 m (3 m).
Mine-Hunting Sonar.......... <=200 1 130 m (54 m)............... 9 m (1 m).
Mine-Hunting Sonar.......... <=200 30 291 m (115 m).............. 16 m (2 m).
Mine-Hunting Sonar.......... <=200 60 453 m (161 m).............. 24 m (3 m).
Mine-Hunting Sonar.......... <=200 120 653 m (198 m).............. 35 m (6 m).
Mine-Hunting Sonar.......... >200 1 90 m (6 m)................. 8 m (1 m).
Mine-Hunting Sonar.......... >200 30 150 m (15 m)............... 15 m (0 m).
Mine-Hunting Sonar.......... >200 60 210 m (30 m)............... 22 m (0 m).
Mine-Hunting Sonar.......... >200 120 300 m (45 m)............... 30 m (0 m).
Sonobuoy Sonar.............. <=200 1 65 m (22 m)................ 0 m (3 m).
Sonobuoy Sonar.............. <=200 30 140 m (67 m)............... 9 m (4 m).
Sonobuoy Sonar.............. <=200 60 218 m (98 m)............... 15 m (5 m).
Sonobuoy Sonar.............. <=200 120 349 m (128 m).............. 22 m (7 m).
Sonobuoy Sonar.............. >200 1 65 m (31 m)................ 0 m (1 m).

[[Page 19959]]

Sonobuoy Sonar.............. >200 30 110 m (60 m)............... 0 m (5 m).
Sonobuoy Sonar.............. >200 60 180 m (87 m)............... 10 m (6 m).
Sonobuoy Sonar.............. >200 120 280 m (72 m)............... 21 m (10 m).
----------------------------------------------------------------------------------------------------------------
Note: Median ranges are shown with standard deviation ranges in parentheses.

Table 26--Phocid Carnivore in Water Ranges to Effects for Sonar
----------------------------------------------------------------------------------------------------------------
Duration
Sonar type Depth (m) (s) Range to TTS Range to AUD INJ
----------------------------------------------------------------------------------------------------------------
Dipping Sonar............... <=200 1 208 m (63 m)............... 0 m (7 m).
Dipping Sonar............... <=200 30 410 m (87 m)............... 22 m (8 m).
Dipping Sonar............... <=200 60 564 m (117 m).............. 30 m (10 m).
Dipping Sonar............... <=200 120 853 m (170 m).............. 45 m (15 m).
Dipping Sonar............... >200 1 170 m (80 m)............... 0 m (6 m).
Dipping Sonar............... >200 30 300 m (73 m)............... 0 m (11 m).
Dipping Sonar............... >200 60 400 m (84 m)............... 0 m (14 m).
Dipping Sonar............... >200 120 600 m (131 m).............. 35 m (21 m).
MF1 Ship Sonar.............. <=200 1 2,181 m (982 m)............ 120 m (16 m).
MF1 Ship Sonar.............. <=200 30 2,181 m (982 m)............ 120 m (16 m).
MF1 Ship Sonar.............. <=200 60 3,417 m (1,671 m).......... 186 m (28 m).
MF1 Ship Sonar.............. <=200 120 4,306 m (2,258 m).......... 240 m (41 m).
MF1 Ship Sonar.............. >200 1 1,500 m (708 m)............ 120 m (5 m).
MF1 Ship Sonar.............. >200 30 1,500 m (708 m)............ 120 m (5 m).
MF1 Ship Sonar.............. >200 60 2,667 m (1,231 m).......... 180 m (9 m).
MF1 Ship Sonar.............. >200 120 3,819 m (1,543 m).......... 230 m (13 m).
MF1C Ship Sonar............. <=200 1 2,181 m (982 m)............ 120 m (16 m).
MF1C Ship Sonar............. <=200 30 4,333 m (2,258 m).......... 240 m (41 m).
MF1C Ship Sonar............. <=200 60 6,194 m (3,650 m).......... 381 m (77 m).
MF1C Ship Sonar............. <=200 120 8,556 m (5,510 m).......... 606 m (130 m).
MF1C Ship Sonar............. >200 1 1,500 m (708 m)............ 120 m (5 m).
MF1C Ship Sonar............. >200 30 3,819 m (1,543 m).......... 230 m (13 m).
MF1C Ship Sonar............. >200 60 5,264 m (2,269 m).......... 330 m (28 m).
MF1C Ship Sonar............. >200 120 7,292 m (3,235 m).......... 480 m (59 m).
MF1K Ship Sonar............. <=200 1 270 m (43 m)............... 17 m (6 m).
MF1K Ship Sonar............. <=200 30 557 m (104 m).............. 30 m (4 m).
MF1K Ship Sonar............. <=200 60 775 m (155 m).............. 40 m (3 m).
MF1K Ship Sonar............. <=200 120 1,000 m (312 m)............ 65 m (5 m).
MF1K Ship Sonar............. >200 1 240 m (8 m)................ 16 m (6 m).
MF1K Ship Sonar............. >200 30 430 m (27 m)............... 30 m (11 m).
MF1K Ship Sonar............. >200 60 550 m (47 m)............... 35 m (14 m).
MF1K Ship Sonar............. >200 120 800 m (98 m)............... 60 m (3 m).
Mine-Hunting Sonar.......... <=200 1 15 m (5 m)................. 0 m (0 m).
Mine-Hunting Sonar.......... <=200 30 25 m (6 m)................. 0 m (1 m).
Mine-Hunting Sonar.......... <=200 60 40 m (8 m)................. 0 m (2 m).
Mine-Hunting Sonar.......... <=200 120 65 m (13 m)................ 4 m (2 m).
Mine-Hunting Sonar.......... >200 1 14 m (4 m)................. 0 m (0 m).
Mine-Hunting Sonar.......... >200 30 25 m (2 m)................. 0 m (1 m).
Mine-Hunting Sonar.......... >200 60 35 m (2 m)................. 0 m (1 m).
Mine-Hunting Sonar.......... >200 120 50 m (2 m)................. 3 m (2 m).
Sonobuoy Sonar.............. <=200 1 21 m (9 m)................. 0 m (0 m).
Sonobuoy Sonar.............. <=200 30 35 m (11 m)................ 0 m (1 m).
Sonobuoy Sonar.............. <=200 60 50 m (15 m)................ 0 m (2 m).
Sonobuoy Sonar.............. <=200 120 75 m (23 m)................ 0 m (3 m).
Sonobuoy Sonar.............. >200 1 0 m (10 m)................. 0 m (0 m).
Sonobuoy Sonar.............. >200 30 35 m (17 m)................ 0 m (1 m).
Sonobuoy Sonar.............. >200 60 50 m (22 m)................ 0 m (2 m).
Sonobuoy Sonar.............. >200 120 75 m (33 m)................ 0 m (2 m).
----------------------------------------------------------------------------------------------------------------
Note: Median ranges are shown with standard deviation ranges in parentheses.

Air Guns
Ranges to effects for air guns were determined by modeling the
distance that sound would need to propagate to reach exposure level
thresholds specific to a hearing group that would cause behavioral
response, TTS, and AUD INJ, as described in the ``Criteria and
Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase
4)'' report (U.S. Department of the Navy, 2024)). The air gun ranges to
effects for TTS and AUD INJ in table 27 are based on the metric (i.e.,
SEL or SPL) that produced larger ranges.

[[Page 19960]]

Table 27--Range to Effects for Air Guns
--------------------------------------------------------------------------------------------------------------------------------------------------------
Functional hearing group Depth (m) Behavioral disturbance Range to TTS Range to AUD INJ
--------------------------------------------------------------------------------------------------------------------------------------------------------
VLF.................................. <=200 145 m (20 m).................... 27 m (1 m)...................... 4 m (1 m).
VLF.................................. >200 143 m (20 m).................... 26 m (1 m)...................... 4 m (1 m).
LF................................... <=200 130 m (18 m).................... 12 m (0 m)...................... 2 m (0 m).
LF................................... >200 130 m (17 m).................... 12 m (0 m)...................... 2 m (0 m).
HF................................... <=200 146 m (20 m).................... 2 m (0 m)....................... 1 m (0 m).
HF................................... >200 145 m (18 m).................... 2 m (0 m)....................... 1 m (0 m).
VHF.................................. <=200 150 m (18 m).................... 56 m (3 m)...................... 27 m (2 m).
VHF.................................. >200 148 m (16 m).................... 55 m (3 m)...................... 27 m (2 m).
PW................................... <=200 142 m (18 m).................... 5 m (1 m)....................... 2 m (0 m).
PW................................... >200 139 m (17 m).................... 5 m (1 m)....................... 2 m (0 m).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: The values listed for TTS and AUD INJ are the greater of the respective SPL and SEL ranges. Median ranges are shown with standard deviation ranges
in parentheses. The Action Proponents split the LF functional hearing group into LF and VLF based on Houser et al., (2024), however, NMFS updated
acoustic technical guidance (NMFS, 2024) does not include these data but we have included the VLF group here for reference.

Pile Driving
Only two stocks of bottlenose dolphins (Gulf of America Northern
Coastal stock and Mississippi Sound, Lake Borgne, and Bay Boudreau
stock) are expected to be present in the nearshore waters of Gulfport,
Mississippi, where impact and vibratory pile driving and extraction is
proposed to occur up to four times per year. Table 28 shows the
predicted ranges to AUD INJ, TTS, and behavioral response for the HF
hearing group (the only functional hearing group expected in the
vicinity of pile driving and extraction activities) that were analyzed
for their exposure to impact and vibratory pile driving. These ranges
were estimated based on activity parameters described in the Acoustic
Stressors section of the Explosive and Acoustic Analysis Report (see
appendix A of the application) and using the calculations described in
the Quantitative Analysis Technical Report (see ``Quantifying Acoustic
Impacts on Marine Mammals and Sea Turtles: Methods and Analytical
Approach for Phase IV Training and Testing'' (U.S. Department of the
Navy, 2024)).

Table 28--Range to Effects for High-Frequency Cetaceans From Pile Driving
----------------------------------------------------------------------------------------------------------------
Behavioral
Pile type Method response (m) TTS (m) AUD INJ (m)
----------------------------------------------------------------------------------------------------------------
16-inch timber/plastic................ Impact.................. 46 17 2
16-inch timber/plastic................ Vibratory............... 6,310 17 1
24-inch steel sheet................... Vibratory............... 3,981 11 0
----------------------------------------------------------------------------------------------------------------

Explosives
The following section provides the range (distance) over which
specific physiological or behavioral effects are expected to occur
based on the explosive criteria (see section 6.2.1 (Impacts from
Explosives) of the application and the ``Criteria and Thresholds for
U.S. Navy Acoustic and Explosive Effects Analysis (Phase 4)'' report
(U.S. Department of the Navy, 2024)) and the explosive propagation
calculations from NAEMO. The range to effects are shown for a range of
explosive bins, from E1 (0.1-0.25 lb NEW) to E16 (greater than 7,250-
14,500 lb NEW (ship shock trial only)) (table 29 through table 33).
Ranges are determined by modeling the distance that noise from an
explosion would need to propagate to reach exposure level thresholds
specific to a hearing group that would cause behavioral response (to
the degree of Level B behavioral harassment), TTS, and AUD INJ. NMFS
has reviewed the range distance to effect data provided by the Action
Proponents and concurs with the analysis. Range to effects is important
information in not only predicting impacts from explosives, but also in
verifying the accuracy of model results against real-world situations
and determining adequate mitigation ranges to avoid higher level
effects, especially injury to marine mammals. For additional
information on how ranges to impacts from explosions were estimated,
see the technical report ``Quantifying Acoustic Impacts on Marine
Mammals and Sea Turtles: Methods and Analytical Approach for Phase IV
Training and Testing'' (U.S. Department of the Navy, 2024).
Table 29 through table 33 show the minimum, average, and maximum
ranges to onset of auditory and likely behavioral effects that rise to
the level of Level B harassment for all functional hearing groups based
on the developed thresholds. Ranges are provided for a representative
source depth and cluster size (the number of rounds fired, or buoys
dropped, within a very short duration) for each bin. Ranges for
behavioral response are only provided if more than one explosive
cluster occurs. As noted previously, single explosions at received
sound levels below TTS and AUD INJ thresholds are most likely to result
in a brief alerting or orienting response. For events with multiple
explosions, sound from successive explosions can be expected to
accumulate and increase the range to the onset of an impact based on
SEL thresholds. Modeled ranges to TTS and AUD INJ based on peak
pressure for a single explosion generally exceed the modeled ranges
based on SEL even when accumulated for multiple explosions. Peak
pressure-based ranges are estimated using the best available science;
however, data on peak pressure at far distances from explosions are
very limited. The explosive ranges to effects for TTS and AUD INJ that
are in the tables are based on the metric (i.e., SEL or SPL) that
produced larger ranges.
Table 34 shows ranges to non-auditory injury and mortality as a

[[Page 19961]]

function of animal mass and explosive bin. For non-auditory injury, the
larger of the ranges to slight lung injury or gastrointestinal tract
injury was used as a conservative estimate, and the boxplots in
appendix A to the application present ranges for both metrics for
comparison. For the non-auditory metric, ranges are only available for
a cluster size of one. Animals within water volumes encompassing the
estimated range to non-auditory injury would be expected to receive
minor injuries at the outer ranges, increasing to more substantial
injuries, and finally mortality as an animal approaches the detonation
point.

Table 29--Very Low-Frequency Cetacean Ranges to Effects for Explosives
----------------------------------------------------------------------------------------------------------------
Range to
Bin Depth (m) Cluster size behavioral Range to TTS Range to AUD INJ
disturbance
----------------------------------------------------------------------------------------------------------------
E1............... <=200 1 NA............. 310 m (149 m).. 97 m (6 m).
E1............... <=200 25 1,250 m (336 m) 800 m (112 m).. 199 m (39 m).
E1............... <=200 100 5,049 m (2,982 1,604 m (1,238 353 m (74 m).
m). m).
E1............... >200 1 NA............. 305 m (88 m)... 96 m (6 m).
E2............... <=200 1 NA............. 292 m (9 m).... 98 m (0 m).
E3............... <=200 1 NA............. 542 m (531 m).. 206 m (22 m).
E3............... <=200 10 3,569 m (2,949 1,264 m (904 m) 274 m (75 m).
m).
E3............... >200 1 NA............. 480 m (275 m).. 208 m (20 m).
E3............... >200 10 1,500 m (881 m) 925 m (301 m).. 290 m (67 m).
E4............... <=200 1 NA............. 2,625 m (1,017 378 m (143 m).
m).
E4............... >200 1 NA............. 1,000 m (160 m) 353 m (34 m).
E5............... <=200 1 NA............. 879 m (1,240 m) 309 m (35 m).
E5............... <=200 8 11,590 m (7,473 5,375 m (3,258 389 m (119 m).
m). m).
E5............... >200 1 NA............. 650 m (221 m).. 304 m (33 m).
E5............... >200 8 1,750 m (1,403 1,000 m (654 m) 420 m (92 m).
m).
E6............... <=200 1 NA............. 1,472 m (2,322 421 m (56 m).
m).
E6............... <=200 4 16,812 m (4,849 7,131 m (3,505 421 m (56 m).
m). m).
E6............... >200 1 NA............. 743 m (100 m).. 426 m (43 m).
E7............... <=200 1 NA............. 2,649 m (919 m) 510 m (62 m).
E7............... >200 1 NA............. 2,989 m (1,004 515 m (66 m).
m).
E8............... <=200 1 NA............. 5,619 m (1,462 767 m (114 m).
m).
E8............... >200 1 NA............. 5,577 m (1,617 781 m (115 m).
m).
E9............... <=200 1 NA............. 6,717 m (3,010 676 m (98 m).
m).
E9............... >200 1 NA............. 6,141 m (2,970 646 m (89 m).
m).
E10.............. <=200 1 NA............. 12,778 m (4,320 875 m (153 m).
m).
E10.............. >200 1 NA............. 12,964 m (3,612 912 m (158 m).
m).
E11.............. <=200 1 NA............. 23,156 m (5,301 3,790 m (770 m).
m).
E11.............. >200 1 NA............. 22,108 m (4,622 3,625 m (664 m).
m).
E12.............. <=200 1 NA............. 14,652 m (4,177 1,105 m (465 m).
m).
E12.............. >200 1 NA............. 16,150 m (3,598 1,093 m (205 m).
m).
E16.............. >200 1 NA............. 57,600 m (5,145 16,753 m (2,305 m).
m).
----------------------------------------------------------------------------------------------------------------
Note: Behavioral response criteria are applied to explosive clusters >1. The values listed for TTS and AUD INJ
are the greater of the respective SPL and SEL ranges. Median ranges are shown with standard deviation ranges
in parentheses. The Action Proponents split the LF functional hearing group into LF and VLF based on Houser et
al., (2024), however, NMFS updated acoustic technical guidance (NMFS, 2024) does not include these data but we
have included the VLF group here for reference. E1 (0.1-0.25 lbs), E2 (>0.25-0.5 lbs), E3 (>0.5-2.5 lbs), E4
(>2.5-5 lbs), E5 (>5-10 lbs), E6 (>10-20 lbs), E7 (>20-60 lbs), E8 (>60-100 lbs), E9 (>100-250 lbs), E10 (>250-
500 lbs), E11 (>500-675 lbs), E12 (>675-1,000 lbs), E16 (10,000 lbs).

Table 30--Low-Frequency Cetacean Ranges to Effects for Explosives
----------------------------------------------------------------------------------------------------------------
Range to
Bin Depth (m) Cluster size behavioral Range to TTS Range to AUD INJ
disturbance
----------------------------------------------------------------------------------------------------------------
E1............... <=200 1 NA............. 350 m (149 m).. 99 m (4 m).
E1............... <=200 25 1,625 m (321 m) 982 m (46 m)... 288 m (28 m).
E1............... <=200 100 5,021 m (2,386 1,993 m (1,282 501 m (53 m).
m). m).
E1............... >200 1 NA............. 340 m (51 m)... 99 m (5 m).
E2............... <=200 1 NA............. 375 m (6 m).... 98 m (0 m).
E3............... <=200 1 NA............. 626 m (459 m).. 195 m (22 m).
E3............... <=200 10 3,312 m (2,425 1,500 m (817 m) 371 m (62 m).
m).
E3............... >200 1 NA............. 550 m (254 m).. 196 m (18 m).
E3............... >200 10 1,743 m (1,121 1,000 m (333 m) 330 m (41 m).
m).
E4............... <=200 1 NA............. 2,347 m (913 m) 353 m (120 m).
E4............... >200 1 NA............. 1,000 m (152 m) 350 m (36 m).
E5............... <=200 1 NA............. 956 m (1,114 m) 292 m (33 m).
E5............... <=200 8 9,667 m (5,924 4,569 m (2,412 509 m (78 m).
m). m).
E5............... >200 1 NA............. 725 m (173 m).. 289 m (33 m).
E5............... >200 8 1,750 m (1,640 1,250 m (793 m) 470 m (78 m).
m).
E6............... <=200 1 NA............. 1,431 m (2,018 412 m (79 m).
m).
E6............... <=200 4 11,125 m (4,506 6,000 m (2,989 500 m (51 m).
m). m).
E6............... >200 1 NA............. 922 m (855 m).. 417 m (76 m).
E7............... <=200 1 NA............. 2,818 m (1,316 492 m (147 m).
m).
E7............... >200 1 NA............. 2,822 m (1,165 495 m (173 m).
m).

[[Page 19962]]

E8............... <=200 1 NA............. 4,664 m (1,107 745 m (111 m).
m).
E8............... >200 1 NA............. 4,656 m (1,243 746 m (106 m).
m).
E9............... <=200 1 NA............. 4,954 m (2,390 656 m (92 m).
m).
E9............... >200 1 NA............. 4,786 m (3,126 623 m (92 m).
m).
E10.............. <=200 1 NA............. 9,549 m (3,317 850 m (166 m).
m).
E10.............. >200 1 NA............. 10,163 m (3,324 889 m (171 m).
m).
E11.............. <=200 1 NA............. 17,248 m (5,803 2,753 m (791 m).
m).
E11.............. >200 1 NA............. 15,925 m (5,288 2,625 m (668 m).
m).
E12.............. <=200 1 NA............. 11,344 m (2,290 1,003 m (112 m).
m).
E12.............. >200 1 NA............. 12,974 m (2,952 982 m (108 m).
m).
E16.............. >200 1 NA............. 43,847 m (4,420 9,408 m (2,314 m).
m).
----------------------------------------------------------------------------------------------------------------
Note: Behavioral response criteria are applied to explosive clusters >1. The values listed for TTS and AUD INJ
are the greater of the respective SPL and SEL ranges. Median ranges are shown with standard deviation ranges
in parentheses. The Action Proponents split the LF functional hearing group into LF and VLF based on Houser et
al., (2024), however, NMFS updated acoustic technical guidance (NMFS, 2024) does not include these data but we
have included the VLF group here for reference. E1 (0.1-0.25 lbs), E2 (>0.25-0.5 lbs), E3 (>0.5-2.5 lbs), E4
(>2.5-5 lbs), E5 (>5-10 lbs), E6 (>10-20 lbs), E7 (>20-60 lbs), E8 (>60-100 lbs), E9 (>100-250 lbs), E10 (>250-
500 lbs), E11 (>500-675 lbs), E12 (>675-1,000 lbs), E16 (10,000 lbs).

Table 31--High-Frequency Cetacean Ranges to Effects for Explosives
----------------------------------------------------------------------------------------------------------------
Range to
Bin Depth (m) Cluster size behavioral Range to TTS Range to AUD INJ
disturbance
----------------------------------------------------------------------------------------------------------------
E1............... <=200 1 NA............. 110 m (19 m)... 45 m (1 m).
E1............... <=200 25 757 m (71 m)... 514 m (49 m)... 113 m (6 m).
E1............... <=200 100 1,004 m (133 m) 747 m (77 m)... 240 m (18 m).
E1............... >200 1 NA............. 90 m (3 m)..... 44 m (1 m).
E2............... <=200 1 NA............. 156 m (1 m).... 45 m (1 m).
E3............... <=200 1 NA............. 230 m (57 m)... 94 m (5 m).
E3............... <=200 10 881 m (205 m).. 597 m (114 m).. 150 m (15 m).
E3............... >200 1 NA............. 190 m (23 m)... 95 m (5 m).
E3............... >200 10 525 m (172 m).. 366 m (79 m)... 120 m (7 m).
E4............... <=200 1 NA............. 427 m (108 m).. 130 m (13 m).
E4............... >200 1 NA............. 278 m (20 m)... 126 m (15 m).
E5............... <=200 1 NA............. 370 m (118 m).. 138 m (11 m).
E5............... <=200 8 1,083 m (343 m) 787 m (105 m).. 220 m (19 m).
E5............... >200 1 NA............. 250 m (28 m)... 137 m (10 m).
E5............... >200 8 625 m (209 m).. 450 m (139 m).. 170 m (10 m).
E6............... <=200 1 NA............. 479 m (174 m).. 187 m (15 m).
E6............... <=200 4 884 m (122 m).. 674 m (95 m)... 220 m (18 m).
E6............... >200 1 NA............. 341 m (27 m)... 191 m (11 m).
E7............... <=200 1 NA............. 544 m (67 m)... 239 m (18 m).
E7............... >200 1 NA............. 552 m (68 m)... 237 m (20 m).
E8............... <=200 1 NA............. 719 m (93 m)... 333 m (37 m).
E8............... >200 1 NA............. 713 m (101 m).. 327 m (40 m).
E9............... <=200 1 NA............. 731 m (90 m)... 336 m (29 m).
E9............... >200 1 NA............. 739 m (99 m)... 325 m (31 m).
E10.............. <=200 1 NA............. 872 m (96 m)... 400 m (37 m).
E10.............. >200 1 NA............. 898 m (107 m).. 398 m (36 m).
E11.............. <=200 1 NA............. 1,857 m (420 m) 839 m (153 m).
E11.............. >200 1 NA............. 1,788 m (375 m) 840 m (159 m).
E12.............. <=200 1 NA............. 1,053 m (96 m). 490 m (43 m).
E12.............. >200 1 NA............. 1,053 m (67 m). 488 m (40 m).
E16.............. >200 1 NA............. 4,306 m (646 m) 1,986 m (367 m).
----------------------------------------------------------------------------------------------------------------
Note: Behavioral response criteria are applied to explosive clusters >1. The values listed for TTS and AUD INJ
are the greater of the respective SPL and SEL ranges. Median ranges are shown with standard deviation ranges
in parentheses. E1 (0.1-0.25 lbs), E2 (>0.25-0.5 lbs), E3 (>0.5-2.5 lbs), E4 (>2.5-5 lbs), E5 (>5-10 lbs), E6
(>10-20 lbs), E7 (>20-60 lbs), E8 (>60-100 lbs), E9 (>100-250 lbs), E10 (>250-500 lbs), E11 (>500-675 lbs),
E12 (>675-1,000 lbs), E16 (10,000 lbs).

Table 32--Very High-Frequency Cetacean Ranges to Effects for Explosives
----------------------------------------------------------------------------------------------------------------
Range to
Bin Depth (m) Cluster size behavioral Range to TTS Range to AUD INJ
disturbance
----------------------------------------------------------------------------------------------------------------
E1............... <=200 1 NA............. 2,306 m (1,200 756 m (54 m).
m).
E1............... <=200 25 8,750 m (2,277 6,201 m (1,446 1,507 m (294 m).
m). m).
E1............... <=200 100 12,639 m (3,565 9,500 m (2,588 2,986 m (991 m).
m). m).
E1............... >200 1 NA............. 1,750 m (1,283 756 m (67 m).
m).
E2............... <=200 1 NA............. 2,319 m (189 m) 636 m (41 m).
E3............... <=200 1 NA............. 4,229 m (1,812 1,369 m (214 m).
m).

[[Page 19963]]

E3............... <=200 10 12,403 m (5,829 9,181 m (4,143 2,319 m (986 m).
m). m).
E3............... >200 1 NA............. 3,188 m (2,063 1,358 m (218 m).
m).
E3............... >200 10 7,931 m (3,781 5,417 m (2,727 1,750 m (521 m).
m). m).
E4............... <=200 1 NA............. 7,708 m (3,229 3,718 m (510 m).
m).
E4............... >200 1 NA............. 6,956 m (940 m) 3,708 m (476 m).
E5............... <=200 1 NA............. 6,188 m (2,432 2,389 m (607 m).
m).
E5............... <=200 8 16,743 m (6,550 12,785 m (4,590 3,708 m (1,410 m).
m). m).
E5............... >200 1 NA............. 5,139 m (1,394 2,400 m (650 m).
m).
E5............... >200 8 6,944 m (3,970 5,139 m (1,394 2,400 m (650 m).
m). m).
E6............... <=200 1 NA............. 8,450 m (1,848 4,163 m (982 m).
m).
E6............... <=200 4 14,139 m (2,139 10,806 m (1,894 4,163 m (982 m).
m). m).
E6............... >200 1 NA............. 8,161 m (1,685 4,142 m (886 m).
m).
E7............... <=200 1 NA............. 9,972 m (2,473 5,417 m (1,153 m).
m).
E7............... >200 1 NA............. 10,797 m (2,602 5,417 m (1,234 m).
m).
E8............... <=200 1 NA............. 15,042 m (2,913 8,474 m (1,510 m).
m).
E8............... >200 1 NA............. 14,576 m (2,952 8,508 m (1,647 m).
m).
E9............... <=200 1 NA............. 17,125 m (4,607 9,306 m (2,744 m).
m).
E9............... >200 1 NA............. 18,111 m (4,553 9,257 m (2,571 m).
m).
E10.............. <=200 1 NA............. 23,389 m (5,616 14,477 m (3,639 m).
m).
E10.............. >200 1 NA............. 24,140 m (5,392 14,360 m (3,368 m).
m).
E11.............. <=200 1 NA............. 32,167 m (5,134 20,460 m (3,618 m).
m).
E11.............. >200 1 NA............. 31,136 m (5,579 19,871 m (3,817 m).
m).
E12.............. <=200 1 NA............. 22,356 m (4,938 13,444 m (3,602 m).
m).
E12.............. >200 1 NA............. 23,368 m (4,434 14,097 m (2,913 m).
m).
E16.............. >200 1 NA............. 63,764 m (5,297 46,979 m (5,225 m).
m).
----------------------------------------------------------------------------------------------------------------
Note: Behavioral response criteria are applied to explosive clusters >1. The values listed for TTS and AUD INJ
are the greater of the respective SPL and SEL ranges. Median ranges are shown with standard deviation ranges
in parentheses. E1 (0.1-0.25 lbs), E2 (>0.25-0.5 lbs), E3 (>0.5-2.5 lbs), E4 (>2.5-5 lbs), E5 (>5-10 lbs), E6
(>10-20 lbs), E7 (>20-60 lbs), E8 (>60-100 lbs), E9 (>100-250 lbs), E10 (>250-500 lbs), E11 (>500-675 lbs),
E12 (>675-1,000 lbs), E16 (10,000 lbs).

Table 33--Phocid Carnivore in Water Ranges to Effects for Explosives
----------------------------------------------------------------------------------------------------------------
Range to
Bin Depth (m) Cluster size behavioral Range to TTS Range to AUD INJ
disturbance
----------------------------------------------------------------------------------------------------------------
E1............... <=200 1 NA............. 342 m (110 m).. 88 m (4 m).
E1............... <=200 25 1,493 m (265 m) 994 m (40 m)... 309 m (25 m).
E1............... <=200 100 3,861 m (2,008 1,833 m (880 m) 500 m (52 m).
m).
E1............... >200 1 NA............. 310 m (36 m)... 88 m (5 m).
E2............... <=200 1 NA............. 382 m (5 m).... 91 m (1 m).
E3............... <=200 1 NA............. 625 m (278 m).. 188 m (16 m).
E3............... <=200 10 2,715 m (1,485 1,319 m (604 m) 393 m (50 m).
m).
E3............... >200 1 NA............. 550 m (174 m).. 188 m (13 m).
E3............... >200 10 1,500 m (909 m) 974 m (267 m).. 320 m (20 m).
E4............... <=200 1 NA............. 1,569 m (638 m) 303 m (37 m).
E4............... >200 1 NA............. 925 m (83 m)... 304 m (32 m).
E5............... <=200 1 NA............. 879 m (736 m).. 273 m (22 m).
E5............... <=200 8 5,840 m (3,339 2,611 m (1,253 517 m (61 m).
m). m).
E5............... >200 1 NA............. 625 m (144 m).. 270 m (20 m).
E5............... >200 8 1,750 m (1,211 1,083 m (616 m) 420 m (50 m).
m).
E6............... <=200 1 NA............. 1,055 m (1,248 361 m (40 m).
m).
E6............... <=200 4 6,556 m (3,277 2,410 m (1,313 487 m (43 m).
m). m).
E6............... >200 1 NA............. 725 m (178 m).. 368 m (29 m).
E7............... <=200 1 NA............. 1,471 m (301 m) 418 m (35 m).
E7............... >200 1 NA............. 1,480 m (304 m) 411 m (36 m).
E8............... <=200 1 NA............. 2,974 m (660 m) 683 m (96 m).
E8............... >200 1 NA............. 2,900 m (761 m) 704 m (92 m).
E9............... <=200 1 NA............. 2,761 m (812 m) 611 m (88 m).
E9............... >200 1 NA............. 2,713 m (702 m) 578 m (87 m).
E10.............. <=200 1 NA............. 4,917 m (1,223 770 m (117 m).
m).
E10.............. >200 1 NA............. 4,967 m (1,132 790 m (148 m).
m).
E11.............. <=200 1 NA............. 12,592 m (2,706 2,312 m (460 m).
m).
E11.............. >200 1 NA............. 11,950 m (2,415 2,225 m (366 m).
m).
E12.............. <=200 1 NA............. 5,578 m (1,142 903 m (110 m).
m).
E12.............. >200 1 NA............. 6,146 m (1,343 869 m (93 m).
m).
E16.............. >200 1 NA............. 24,319 m (1,977 5,478 m (1,106 m).
m).
----------------------------------------------------------------------------------------------------------------
Note: Behavioral response criteria are applied to explosive clusters >1. The values listed for TTS and AUD INJ
are the greater of the respective SPL and SEL ranges. Median ranges are shown with standard deviation ranges
in parentheses. E1 (0.1-0.25 lbs), E2 (>0.25-0.5 lbs), E3 (>0.5-2.5 lbs), E4 (>2.5-5 lbs), E5 (>5-10 lbs), E6
(>10-20 lbs), E7 (>20-60 lbs), E8 (>60-100 lbs), E9 (>100-250 lbs), E10 (>250-500 lbs), E11 (>500-675 lbs),
E12 (>675-1,000 lbs), E16 (10,000 lbs).

[[Page 19964]]

Table 34--Explosive Ranges to Non-Auditory Injury and Mortality for All Marine Mammal Hearing Groups as a Function of Animal Mass
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Bin Effect 10 kg 250 kg 1,000 kg 5,000 kg 25,000 kg 72,000 kg
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
E1............. Non-auditory injury. 22 m (0 m).............. 22 m (1 m).............. 22 m (1 m).............. 22 m (1 m).............. 22 m (0 m).............. 22 m (0 m).
E1............. Mortality........... 4 m (0 m)............... 1 m (1 m)............... 0 m (0 m)............... 0 m (0 m)............... 0 m (0 m)............... 0 m (0 m).
E2............. Non-auditory injury. 26 m (1 m).............. 25 m (1 m).............. 26 m (2 m).............. 26 m (0 m).............. 26 m (1 m).............. 26 m (0 m).
E2............. Mortality........... 4 m (0 m)............... 2 m (1 m)............... 1 m (0 m)............... 0 m (0 m)............... 0 m (0 m)............... 0 m (0 m).
E3............. Non-auditory injury. 47 m (1 m).............. 47 m (3 m).............. 46 m (5 m).............. 46 m (2 m).............. 46 m (2 m).............. 46 m (2 m).
E3............. Mortality........... 10 m (1 m).............. 5 m (2 m)............... 2 m (1 m)............... 1 m (0 m)............... 0 m (0 m)............... 0 m (0 m).
E4............. Non-auditory injury. 58 m (6 m).............. 58 m (6 m).............. 60 m (7 m).............. 64 m (6 m).............. 62 m (8 m).............. 64 m (5 m).
E4............. Mortality........... 23 m (3 m).............. 12 m (4 m).............. 5 m (1 m)............... 3 m (1 m)............... 2 m (0 m)............... 1 m (0 m).
E5............. Non-auditory injury. 74 m (4 m).............. 73 m (7 m).............. 73 m (10 m)............. 75 m (4 m).............. 73 m (6 m).............. 75 m (4 m).
E5............. Mortality........... 17 m (3 m).............. 9 m (3 m)............... 4 m (1 m)............... 3 m (1 m)............... 1 m (0 m)............... 1 m (0 m).
E6............. Non-auditory injury. 95 m (4 m).............. 95 m (7 m).............. 94 m (11 m)............. 97 m (5 m).............. 94 m (9 m).............. 97 m (4 m).
E6............. Mortality........... 34 m (7 m).............. 16 m (6 m).............. 8 m (2 m)............... 5 m (1 m)............... 2 m (1 m)............... 1 m (0 m).
E7............. Non-auditory injury. 121 m (8 m)............. 122 m (9 m)............. 121 m (15 m)............ 125 m (7 m)............. 117 m (18 m)............ 125 m (7 m).
E7............. Mortality........... 40 m (9 m).............. 19 m (7 m).............. 11 m (4 m).............. 7 m (2 m)............... 3 m (2 m)............... 2 m (1 m).
E8............. Non-auditory injury. 206 m (38 m)............ 159 m (19 m)............ 159 m (21 m)............ 162 m (18 m)............ 158 m (20 m)............ 165 m (19 m).
E8............. Mortality........... 74 m (15 m)............. 34 m (13 m)............. 16 m (5 m).............. 11 m (2 m).............. 3 m (2 m)............... 3 m (1 m).
E9............. Non-auditory injury. 207 m (77 m)............ 184 m (13 m)............ 179 m (16 m)............ 189 m (11 m)............ 174 m (11 m)............ 196 m (11 m).
E9............. Mortality........... 94 m (39 m)............. 22 m (19 m)............. 12 m (1 m).............. 8 m (1 m)............... 4 m (0 m)............... 3 m (0 m).
E10............ Non-auditory injury. 316 m (82 m)............ 219 m (13 m)............ 216 m (15 m)............ 224 m (13 m)............ 214 m (13 m)............ 231 m (12 m).
E10............ Mortality........... 152 m (38 m)............ 54 m (39 m)............. 15 m (2 m).............. 10 m (1 m).............. 6 m (0 m)............... 4 m (0 m).
E11............ Non-auditory injury. 770 m (170 m)........... 421 m (154 m)........... 382 m (68 m)............ 433 m (72 m)............ 372 m (68 m)............ 452 m (63 m).
E11............ Mortality........... 368 m (53 m)............ 197 m (66 m)............ 89 m (11 m)............. 55 m (8 m).............. 25 m (5 m).............. 21 m (3 m).
E12............ Non-auditory injury. 475 m (99 m)............ 277 m (16 m)............ 275 m (19 m)............ 277 m (19 m)............ 273 m (17 m)............ 298 m (16 m).
E12............ Mortality........... 235 m (52 m)............ 118 m (53 m)............ 18 m (10 m)............. 13 m (1 m).............. 7 m (0 m)............... 5 m (0 m).
E16............ Non-auditory injury. 3,139 m (786 m)......... 1,451 m (505 m)......... 1,003 m (115 m)......... 1,097 m (119 m)......... 1,004 m (122 m)......... 1,155 m (132 m).
E16............ Mortality........... 1,222 m (163 m)......... 850 m (167 m)........... 491 m (62 m)............ 350 m (34 m)............ 189 m (10 m)............ 134 m (18 m).
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Median ranges with standard deviation ranges in parentheses. For non-auditory injury ranges, the greater of the respective ranges for 1 percent chance of gastro-intestinal tract injury
and 1 percent chance of injury. E1 (0.1-0.25 lbs), E2 (>0.25-0.5 lbs), E3 (>0.5-2.5 lbs), E4 (>2.5-5 lbs), E5 (>5-10 lbs), E6 (>10-20 lbs), E7 (>20-60 lbs), E8 (>60-100 lbs), E9 (>100-250
lbs), E10 (>250-500 lbs), E11 (>500-675 lbs), E12 (>675-1,000 lbs), E16 (10,000 lbs).

Marine Mammal Density

A quantitative analysis of impacts on a species or stock requires
data on their abundance and distribution that may be affected by
anthropogenic activities in the potentially impacted area. The most
appropriate metric for this type of analysis is density, which is the
number of animals present per unit area. Marine species density
estimation requires a significant amount of effort to both collect and
analyze data to produce a reasonable estimate. Unlike surveys for
terrestrial wildlife, many marine species spend much of their time
submerged and are not easily observed. In order to collect enough
sighting data to make reasonable density estimates, multiple
observations are required, often in areas that are not easily
accessible (e.g., far offshore). Ideally, marine mammal species
sighting data would be collected for the specific area and time period
(e.g., season) of interest and density estimates derived accordingly.
However, in many places, poor weather conditions and high sea states
prohibit the completion of comprehensive visual surveys.
For most cetacean species, abundance is estimated using line-
transect surveys or mark-recapture studies (e.g., Barlow, 2010; Barlow
and Forney, 2007; Calambokidis et al., 2008). This is the general
approach applied in estimating cetacean abundance in NMFS SARs.
Although the single value provides a good average estimate of abundance
(total number of individuals) for a specified area, it does not provide
information on the species distribution or concentrations within that
area, and it does not estimate density for other timeframes or seasons
that were not surveyed. More recently, spatial habitat modeling has
been used to estimate cetacean densities (e.g., Roberts et al. 2023).
These models estimate cetacean density as a continuous function of
habitat variables (e.g., sea surface temperature, seafloor depth, etc.)
and thus allow predictions of cetacean densities on finer spatial
scales than traditional line-transect or mark recapture analyses, and
for areas that have not been surveyed. Within the geographic area that
was modeled, densities can be predicted wherever these habitat
variables can be measured or estimated.
Ideally, density data would be available for all species throughout
the Study Area year-round, in order to best estimate the impacts of
specified activities on marine species. However, in many places, vessel
availability, lack of funding, inclement weather conditions, and high
sea states prevent the completion of comprehensive year-round surveys.
Even with surveys that are completed, poor conditions may result in
lower sighting rates for species that would typically be sighted with
greater frequency under favorable conditions. Lower sighting rates
preclude having an acceptably low uncertainty in the density estimates.
A high level of uncertainty, indicating a low level of confidence in
the density estimate, is typical for species that are rare or difficult
to sight. In areas where survey data are limited or non-existent, known
or inferred associations between marine habitat features and the likely
presence of specific species are sometimes used to predict densities in
the absence of actual animal sightings. Consequently, there is no
single source of density data for every area, species, and season
because of the fiscal costs, resources, and effort involved in
providing enough survey coverage to sufficiently estimate density.
To characterize the marine species density for large oceanic
regions, the Action Proponents review, critically assess, and
prioritize existing density estimates from multiple sources, requiring
the development of a systematic method for selecting the most
appropriate density estimate for each combination of species/stock,
area, and season. The selection and compilation of the best available
marine species density data resulted in the NMSDD, which includes
seasonal density values for every marine mammal species and stock
present within the AFTT Study Area. This database is described in the
``U.S. Navy Marine Species Density Database Phase IV for the Atlantic
Fleet Training and Testing Study Area'' technical report (U.S.
Department of the Navy, 2024),

[[Page 19965]]

hereafter referred to as the Density Technical Report. NMFS reviewed
all cetacean densities provided by the Action Proponents prior to use
in their acoustic analysis for the current rulemaking process.
A variety of density data and density models are needed to develop
a density database that encompasses the entirety of the AFTT Study
Area. Because these data are collected using different methods with
varying amounts of accuracy and uncertainty, the Action Proponents have
developed a hierarchy to ensure the most accurate data is used when
available. The Density Technical Report describes these models in
detail and provides detailed explanations of the models applied to each
species density estimate. The below list describes possible models in
order of preference and use:
1. Density estimates from spatial models are preferred and used
when available because they provide an estimate with the least amount
of uncertainty by deriving estimates for divided segments of the
sampling area. These models (see DiMatteo et al. (2024), Garrison et
al. (2023a, 2023b), and Roberts et al. (2023)) predict spatial
variability of animal presence based on habitat variables (e.g., sea
surface temperature, seafloor depth, etc.). Density spatial models are
developed for areas, species, and, when available, specific timeframes
(months or seasons) with sufficient survey data; therefore, this model
cannot be used for species with low numbers of sightings. In the AFTT
Study Area, density spatial models are available for certain species
along the east coast to the offshore extent of available survey data
and in the Gulf of America. For species not covered by the newer
generation of models, the older Roberts et al. (2016) density estimates
from Phase III could be used.
2. Design-based density models predict animal density based on
survey data. Like spatial density models, they are applied to areas
with survey data. Design-based density models may be stratified, in
which a density is predicted for each sub-region of a survey area,
allowing for better prediction of species distribution across the
density model area. In the AFTT Study Area, stratified density models
are used for certain species on both the east coast and the Gulf of
America. In addition, a few species' stratified density models are
applied to areas east of regions with available survey data and cover a
substantial portion of the Atlantic Ocean portion of the AFTT Study
Area.
3. Extrapolative models are used in areas where there is
insufficient or no survey data. These models use a limited set of
environmental variables to predict probable species densities based on
environmental observations during actual marine mammal surveys (see
Mannocci et al. (2017)). In the AFTT Study Area, extrapolative models
are typically used east of regions with available survey data and cover
a substantial portion of the Atlantic Ocean of the AFTT Study Area.
Because some unsurveyed areas have oceanographic conditions that are
very different from surveyed areas (e.g., the Labrador Sea and North
Atlantic gyre) and some species models rely on a very limited data set,
the predictions of some species' extrapolative density models and some
regions of certain species' extrapolative density models are considered
highly speculative. Extrapolative models are not used in the Gulf of
America.
4. Existing relative environmental suitability models include a
high degree of uncertainty, but are applied when no other model is
available.
When interpreting the results of the quantitative analysis, as
described in the Density Technical Report for Phase III (U.S.
Department of the Navy, 2017), ``it is important to consider that even
the best estimate of marine species density is really a model
representation of the values of concentration where these animals might
occur. Each model is limited to the variables and assumptions
considered by the original data source provider. No mathematical model
representation of any biological population is perfect and with regards
to marine species biodiversity, any single model method will not
completely explain the actual distribution and abundance of marine
mammal species. It is expected that there would be anomalies in the
results that need to be evaluated, with independent information for
each case, to support if we might accept or reject a model or portions
of the model.''
The Action Proponents' estimates of abundance (based on density
estimates used in the AFTT Study Area) utilize NMFS' SARs. For some
species, the stock assessment for a given species may exceed the Navy's
density prediction because those species' home range extends beyond the
Study Area boundaries. For other species, the stock assessment
abundance may be much less than the number of animals in the Navy's
modeling given that the AFTT Study Area extends beyond the U.S. waters
covered by the SAR abundance estimate. The primary source of density
estimates are geographically specific survey data and either peer-
reviewed line-transect estimates or habitat-based density models that
have been extensively validated to provide the most accurate estimates
possible.
NMFS coordinated with the Navy in the development of its take
estimates and concurs that the Navy's approach for density
appropriately utilizes the best available science. Later, in the
Preliminary Analysis and Negligible Impact Determination section, we
assess how the estimated take numbers compare to stock abundance in
order to better understand the potential number of individuals
impacted, and the rationale for which abundance estimate is used is
included there.

Estimated Take From Acoustic Stressors

The 2024 AFTT Draft Supplemental EIS/OEIS considered all military
readiness activities proposed to occur in the AFTT Study Area that have
the potential to result in the MMPA defined take of marine mammals. The
Action Proponents determined that the three stressors below could
result in the incidental taking of marine mammals. NMFS has reviewed
the Action Proponents' data and analysis and determined that it is
complete and accurate and agrees that the following stressors have the
potential to result in takes by harassment of marine mammals from the
specified activities:
Acoustics (sonars and other transducers, air guns, pile
driving/extraction);
Explosives (explosive shock wave and sound, assumed to
encompass the risk due to fragmentation); and
Vessel strike.
Acoustic and explosive sources are likely to result in incidental
takes of marine mammals by harassment. Explosive sources and vessel
strikes have the potential to result in incidental take by injury,
serious injury, and/or mortality.
The quantitative analysis process used for the 2024 AFTT Draft
Supplemental EIS/OEIS and the application to estimate potential
exposures to marine mammals resulting from acoustic and explosive
stressors is detailed in the technical report titled ``Quantifying
Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and
Analytical Approach for Phase IV Training and Testing'' (U.S.
Department of the Navy, 2024).
Regarding how avoidance of loud sources is considered in the take
estimation, NAEMO does not simulate horizontal animat movement during
an event. However, NAEMO approximates marine mammal avoidance of high
sound levels due to exposure to sonars

[[Page 19966]]

in a one-dimensional calculation that scales how far an animat would be
from a sound source based on sensitivity to disturbance, swim speed,
and avoidance duration. This process reduces the sound exposure level
(SEL), defined as the accumulation for a given animat (i.e., a virtual
animal), by reducing the received sound pressure levels (SPL) of
individual exposures based on a spherical spreading calculation from
sources on each unique platform in an event. The onset of avoidance was
based on the BRFs. Avoidance speeds and durations were informed by a
review of available exposure and baseline data. This method captures a
more accurate representation of avoidance by using the received sound
levels, distance to platform, and species-specific criteria to
calculate potential avoidance for each animat than the approach used in
Phase III. However, this avoidance method may underestimate avoidance
of long-duration sources with lower sound levels because it triggers
avoidance calculations based on the highest modeled SPL received level
exceeding p(0.5) on the BRF, rather than on cumulative exposure. This
is because initiation of the avoidance calculation is based on the
highest modeled SPL received level over p(0.5) on the BRF. Please see
section 4.4.2.2 of the technical report titled ``Quantifying Acoustic
Impacts on Marine Mammals and Sea Turtles: Methods and Analytical
Approach for Phase IV Training and Testing'' (U.S. Department of the
Navy, 2024).
Regarding the consideration of mitigation effectiveness in the take
estimation, during military readiness activities, there is typically at
least one, if not numerous, support personnel involved in the activity
(e.g., range support personnel aboard a torpedo retrieval boat or
support aircraft). In addition to the Lookout posted for the purpose of
mitigation, these additional personnel observe and disseminate marine
species sighting information amongst the units participating in the
activity whenever possible as they conduct their primary mission
responsibilities. However, the quantitative analysis does not reduce
model-estimated impacts to account for activity-based mitigation, as
was done in previous phases of AFTT. While the activity-based
mitigation is not quantitatively included in the take estimates, table
2.3-1 of appendix A of the application indicates the percentage of the
instances of take where an animal's closest point of approach was
within a mitigation zone and, therefore, AUD INJ could potentially be
mitigated. Note that these percentages do not account for other
factors, such as the sightability of a given species or viewing
conditions.
Unlike activity-based mitigation, in some cases, implementation of
the proposed geographic mitigation areas are incorporated into the
quantitative analysis. The extent to which the mitigation areas reduce
impacts on the affected species is addressed in the Preliminary
Analysis and Negligible Impact Determination section.
For additional information on the quantitative analysis process,
refer to the technical report titled ``Quantifying Acoustic Impacts on
Marine Mammals and Sea Turtles: Methods and Analytical Approach for
Phase IV Training and Testing'' (U.S. Department of the Navy, 2024) and
sections 6 and 11 of the application.
As a general matter, NMFS does not prescribe the methods for
estimating take for any applicant, but we review and ensure that
applicants use the best available science, and methodologies that are
logical and technically sound. Applicants may use different methods of
calculating take (especially when using models) and still get to a
result that is representative of the best available science and that
allows for a rigorous and accurate evaluation of the effects on the
affected populations. There are multiple pieces of the Navy's take
estimation methods--propagation models, animat movement models, and
behavioral thresholds, for example. NMFS evaluates the acceptability of
these pieces as they evolve and are used in different rules and impact
analyses. Some of the pieces of the Action Proponents' take estimation
process have been used in Navy incidental take rules since 2009 and
undergone multiple public comment processes; all of them have undergone
extensive internal Navy review, and all of them have undergone
comprehensive review by NMFS, which has sometimes resulted in
modifications to methods or models.
The Navy uses rigorous review processes (verification, validation,
and accreditation processes; peer and public review) to ensure the data
and methodology it uses represent the best available science. For
instance, NAEMO is the result of a NMFS-led Center for Independent
Experts (CIE) review of the components used in earlier models. The
acoustic propagation component of NAEMO (CASS/GRAB) is accredited by
the Oceanographic and Atmospheric Master Library (OAML), and many of
the environmental variables used in NAEMO come from approved OAML
databases and are based on in-situ data collection. The animal density
components of NAEMO are base products of the NMSDD, which includes
animal density components that have been validated and reviewed by a
variety of scientists from NMFS Science Centers and academic
institutions. Several components of the model, for example the Duke
University habitat-based density models, have been published in peer
reviewed literature. Additionally, NAEMO simulation components
underwent quality assurance and quality control (QA/QC) review and
validation for model parts such as the scenario builder, acoustic
builder, scenario simulator, etc., conducted by qualified statisticians
and modelers to ensure accuracy. Other models and methodologies have
gone through similar review processes.
In summary, we believe the Action Proponents' methods, including
the method for incorporating avoidance, are the most appropriate
methods for predicting AUD INJ, non-auditory injury, TTS, and
behavioral disturbance. But even with the consideration of avoidance,
given some of the more conservative components of the methodology
(e.g., the thresholds do not consider ear recovery between pulses), we
would describe the application of these methods as identifying the
maximum number of instances in which marine mammals would be reasonably
expected to be taken through AUD INJ, non-auditory injury, TTS, or
behavioral disturbance.
Based on the methods discussed in the previous sections and NAEMO,
the Action Proponents provided their take estimate and request for
authorization of takes incidental to the use of acoustic and explosive
sources for military readiness activities annually (based on the
maximum number of activities that could occur per 12-month period) and
over the 7-year period, as well as the Navy's take request for ship
shock trials, covered by the application. The following species/stocks
present in the AFTT Study Area were modeled by the Navy and estimated
to have 0 takes of any type from any activity source: Central Georgia
Estuarine System stock of bottlenose dolphin, Northern South Carolina
Estuarine System stock of bottlenose dolphin, and the Puerto Rico and
U.S. Virgin Islands stock of sperm whale. NMFS has reviewed the Action
Proponents' data, methodology, and analysis and determined that it is
complete and accurate. NMFS agrees that the estimates for incidental
takes by harassment from all sources requested for authorization are
the maximum number of instances in which marine mammals are reasonably
expected to be

[[Page 19967]]

taken and that the takes by mortality requested for authorization are
for the maximum number of instances mortality or serious injury could
occur, as in the case of ship shock trials and vessel strikes.
Table 35, table 36, and table 37 summarize the maximum annual and
7-year total amount and type of Level A harassment and Level B
harassment that NMFS concurs is reasonably expected to occur by species
and stock for Navy training activities, Navy testing activities, and
Coast Guard training activities, respectively.

Table 35--Incidental Take Estimate by Stock Due to Acoustic and Explosive Sources During Navy Training Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Maximum
annual annual Maximum 7-Year total 7-Year total 7-Year total
Species Stock Level B Level A annual Level B Level A mortality
harassment harassment mortality harassment harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale................ Western..................... 97 1 0 642 2 0
Blue whale................................ Western North Atlantic...... 40 0 0 265 0 0
Bryde's whale............................. Primary..................... 10 0 0 69 0 0
Fin whale................................. Western North Atlantic...... 1,089 6 0 7,585 38 0
Humpback whale............................ Gulf of Maine............... 341 7 0 2,351 41 0
Minke whale............................... Canadian East Coast......... 2,606 18 0 17,676 120 0
Rice's whale.............................. Northern Gulf of America.... 8 1 0 49 1 0
Sei whale................................. Nova Scotia................. 356 3 0 2,430 17 0
Sperm whale............................... North Atlantic.............. 7,189 3 0 50,266 5 0
Sperm whale............................... Northern Gulf of America.... 38 0 0 254 0 0
Dwarf sperm whale......................... Northern Gulf of America.... 14 1 0 87 1 0
Pygmy sperm whale......................... Northern Gulf of America.... 15 2 0 96 2 0
Dwarf sperm whale......................... Western North Atlantic...... 3,678 32 0 25,551 221 0
Pygmy sperm whale......................... Western North Atlantic...... 3,625 34 0 25,175 231 0
Blainville's beaked whale................. Northern Gulf of America.... 12 0 0 79 0 0
Goose-beaked whale........................ Northern Gulf of America.... 41 0 0 281 0 0
Gervais' beaked whale..................... Northern Gulf of America.... 14 0 0 90 0 0
Blainville's beaked whale................. Western North Atlantic...... 15,267 1 0 106,751 1 0
Goose-beaked whale........................ Western North Atlantic...... 66,011 1 0 461,356 3 0
Gervais' beaked whale..................... Western North Atlantic...... 15,761 0 0 110,198 0 0
Northern bottlenose whale................. Western North Atlantic...... 828 0 0 5,789 0 0
Sowerby's beaked whale.................... Western North Atlantic...... 15,846 0 0 110,804 0 0
True's beaked whale....................... Western North Atlantic...... 15,892 0 0 111,111 0 0
Atlantic spotted dolphin.................. Northern Gulf of America.... 792 1 0 5,515 4 0
Bottlenose dolphin........................ Gulf of America Eastern 29 0 0 126 0 0
Coastal.
Bottlenose dolphin........................ Gulf of America Northern 2,094 1 0 14,645 2 0
Coastal.
Bottlenose dolphin........................ Gulf of America Oceanic..... 517 1 0 3,611 1 0
Bottlenose dolphin........................ Gulf of America Western 791 0 0 2,372 0 0
Coastal.
Bottlenose dolphin........................ Mississippi Sound, Lake 1,564 0 0 10,944 0 0
Borgne, and Bay Boudreau.
Bottlenose dolphin........................ Northern Gulf of America 4,665 3 0 31,959 13 0
Continental Shelf.
Bottlenose dolphin........................ Nueces and Corpus Christi 4 0 0 11 0 0
Bays.
Bottlenose dolphin........................ Sabine Lake................. 1 0 0 2 0 0
Bottlenose dolphin........................ St. Andrew Bay.............. 14 0 0 92 0 0
Bottlenose dolphin........................ St. Joseph Bay.............. 7 0 0 47 0 0
Bottlenose dolphin........................ Tampa Bay................... 350 0 0 1,050 0 0
Clymene dolphin........................... Northern Gulf of America.... 66 0 0 459 0 0
False killer whale........................ Northern Gulf of America.... 24 0 0 160 0 0
Fraser's dolphin.......................... Northern Gulf of America.... 25 0 0 159 0 0
Killer whale.............................. Northern Gulf of America.... 13 0 0 82 0 0
Melon-headed whale........................ Northern Gulf of America.... 81 0 0 561 0 0
Pygmy killer whale........................ Northern Gulf of America.... 29 0 0 198 0 0
Risso's dolphin........................... Northern Gulf of America.... 23 0 0 155 0 0
Rough-toothed dolphin..................... Northern Gulf of America.... 128 0 0 866 0 0
Short-finned pilot whale.................. Northern Gulf of America.... 88 0 0 611 0 0
Striped dolphin........................... Northern Gulf of America.... 244 1 0 1,696 1 0
Pantropical spotted dolphin............... Northern Gulf of America.... 720 3 0 5,036 5 0
Spinner dolphin........................... Northern Gulf of America.... 20 0 0 135 0 0
Atlantic white-sided dolphin.............. Western North Atlantic...... 3,233 4 0 22,590 18 0
Common dolphin............................ Western North Atlantic...... 165,863 39 0 1,160,553 261 0
Atlantic spotted dolphin.................. Western North Atlantic...... 74,649 27 0 508,116 179 0
Bottlenose dolphin........................ Indian River Lagoon 1,422 0 0 9,601 0 0
Estuarine System.
Bottlenose dolphin........................ Jacksonville Estuarine 348 0 0 2,408 0 0
System.
Bottlenose dolphin........................ Northern Georgia/Southern 2 0 0 6 0 0
South Carolina Estuarine
System.
Bottlenose dolphin........................ Northern North Carolina 9,181 3 0 63,391 20 0
Estuarine System.
Bottlenose dolphin........................ Southern Georgia Estuarine 122 1 0 710 1 0
System.
Bottlenose dolphin........................ Southern North Carolina 162 0 0 535 0 0
Estuarine System.
Tamanend's bottlenose dolphin............. Western North Atlantic 7,692 2 0 49,736 6 0
Central Florida Coastal.
Tamanend's bottlenose dolphin............. Western North Atlantic 17,003 2 0 116,702 4 0
Northern Florida Coastal.
Bottlenose dolphin........................ Western North Atlantic 64,712 34 0 450,293 227 0
Northern Migratory Coastal.
Bottlenose dolphin........................ Western North Atlantic 120,151 27 1 818,458 173 1
Offshore.
Tamanend's bottlenose dolphin............. Western North Atlantic South 3,867 3 1 24,408 11 1
Carolina/Georgia Coastal.

[[Page 19968]]

Bottlenose dolphin........................ Western North Atlantic 8,868 7 0 56,933 44 0
Southern Migratory Coastal.
Clymene dolphin........................... Western North Atlantic...... 69,460 15 1 486,205 94 3
False killer whale........................ Western North Atlantic...... 406 0 0 2,821 0 0
Fraser's dolphin.......................... Western North Atlantic...... 1,904 2 0 12,826 8 0
Killer whale.............................. Western North Atlantic...... 110 0 0 759 0 0
Long-finned pilot whale................... Western North Atlantic...... 13,501 5 0 94,499 18 0
Melon-headed whale........................ Western North Atlantic...... 3,517 1 0 23,968 2 0
Pantropical spotted dolphin............... Western North Atlantic...... 10,976 3 0 75,620 12 0
Pygmy killer whale........................ Western North Atlantic...... 368 1 0 2,512 1 0
Risso's dolphin........................... Western North Atlantic...... 22,128 5 0 150,830 24 0
Rough-toothed dolphin..................... Western North Atlantic...... 3,365 3 0 22,647 10 0
Short-finned pilot whale.................. Western North Atlantic...... 21,745 3 0 149,080 18 0
Spinner dolphin........................... Western North Atlantic...... 4,185 1 0 28,962 3 0
Striped dolphin........................... Western North Atlantic...... 121,279 26 0 848,940 178 0
White-beaked dolphin...................... Western North Atlantic...... 4 0 0 27 0 0
Harbor porpoise........................... Gulf of Maine/Bay of Fundy.. 36,396 73 0 253,899 505 0
Gray seal................................. Western North Atlantic...... 7,862 14 0 54,598 93 0
Harbor seal............................... Western North Atlantic...... 11,207 18 0 77,914 125 0
Harp seal................................. Western North Atlantic...... 14,632 2 0 102,365 12 0
Hooded seal............................... Western North Atlantic...... 460 1 0 3,205 1 0
--------------------------------------------------------------------------------------------------------------------------------------------------------

Table 36--Incidental Take Estimate by Stock Due to Acoustic and Explosive Source During Navy Testing Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Maximum
annual annual Maximum 7-Year total 7-Year total 7-Year total
Species Stock Level B Level A annual Level B Level A mortality
harassment harassment mortality harassment harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale................ Western..................... 316 1 0 2,036 6 0
Blue whale................................ Western North Atlantic...... 31 1 0 199 2 0
Bryde's whale............................. Primary..................... 1 0 0 1 0 0
Fin whale................................. Western North Atlantic...... 1,524 15 0 9,710 93 0
Humpback whale............................ Gulf of Maine............... 500 5 0 3,186 33 0
Minke whale............................... Canadian East Coast......... 2,032 38 0 13,316 257 0
Rice's whale.............................. Northern Gulf of America.... 294 2 0 1,997 5 0
Sei whale................................. Nova Scotia................. 389 4 0 2,549 27 0
Sperm whale............................... North Atlantic.............. 5,395 4 0 34,373 16 0
Sperm whale............................... Northern Gulf of America.... 237 0 0 1,399 0 0
Dwarf sperm whale......................... Northern Gulf of America.... 173 21 0 1,023 72 0
Pygmy sperm whale......................... Northern Gulf of America.... 158 20 0 919 63 0
Dwarf sperm whale......................... Western North Atlantic...... 2,640 147 0 16,951 962 0
Pygmy sperm whale......................... Western North Atlantic...... 2,663 141 0 17,096 925 0
Blainville's beaked whale................. Northern Gulf of America.... 114 0 0 733 0 0
Goose-beaked whale........................ Northern Gulf of America.... 419 0 0 2,681 0 0
Gervais' beaked whale..................... Northern Gulf of America.... 111 0 0 710 0 0
Blainville's beaked whale................. Western North Atlantic...... 10,431 0 0 65,790 0 0
Goose-beaked whale........................ Western North Atlantic...... 46,017 1 0 290,954 2 0
Gervais' beaked whale..................... Western North Atlantic...... 9,678 1 0 62,096 1 0
Northern bottlenose whale................. Western North Atlantic...... 823 1 0 5,090 1 0
Sowerby's beaked whale.................... Western North Atlantic...... 9,770 1 0 62,705 1 0
True's beaked whale....................... Western North Atlantic...... 9,684 0 0 62,151 0 0
Atlantic spotted dolphin.................. Northern Gulf of America.... 11,976 19 0 78,071 119 0
Bottlenose dolphin........................ Gulf of America Eastern 51 0 0 329 0 0
Coastal.
Bottlenose dolphin........................ Gulf of America Northern 5,052 16 0 35,305 112 0
Coastal.
Bottlenose dolphin........................ Gulf of America Oceanic..... 5,755 3 0 36,970 10 0
Bottlenose dolphin........................ Gulf of America Western 2,540 1 0 15,751 1 0
Coastal.
Bottlenose dolphin........................ Mississippi Sound, Lake 194 1 0 1,070 1 0
Borgne, and Bay Boudreau.
Bottlenose dolphin........................ Northern Gulf of America 66,581 25 0 448,847 151 0
Continental Shelf.
Bottlenose dolphin........................ St. Andrew Bay.............. 32 0 0 211 0 0
Bottlenose dolphin........................ St. Joseph Bay.............. 35 0 0 240 0 0
Clymene dolphin........................... Northern Gulf of America.... 533 3 0 3,118 4 0
False killer whale........................ Northern Gulf of America.... 206 0 0 1,263 0 0
Fraser's dolphin.......................... Northern Gulf of America.... 216 0 0 1,328 0 0
Killer whale.............................. Northern Gulf of America.... 97 0 0 598 0 0
Melon-headed whale........................ Northern Gulf of America.... 690 1 0 4,245 1 0
Pygmy killer whale........................ Northern Gulf of America.... 256 0 0 1,575 0 0
Risso's dolphin........................... Northern Gulf of America.... 180 0 0 1,097 0 0
Rough-toothed dolphin..................... Northern Gulf of America.... 1,510 3 0 9,920 5 0
Short-finned pilot whale.................. Northern Gulf of America.... 933 3 0 5,572 13 0
Striped dolphin........................... Northern Gulf of America.... 2,132 6 1 13,718 14 2
Pantropical spotted dolphin............... Northern Gulf of America.... 5,596 6 2 34,923 23 5
Spinner dolphin........................... Northern Gulf of America.... 636 0 0 4,324 0 0

[[Page 19969]]

Atlantic white-sided dolphin.............. Western North Atlantic...... 7,662 5 0 49,052 25 0
Common dolphin............................ Western North Atlantic...... 103,523 121 0 659,876 753 0
Atlantic spotted dolphin.................. Western North Atlantic...... 46,117 60 0 288,483 398 0
Bottlenose dolphin........................ Indian River Lagoon 154 0 0 1,074 0 0
Estuarine System.
Bottlenose dolphin........................ Jacksonville Estuarine 12 0 0 69 0 0
System.
Bottlenose dolphin........................ Northern North Carolina 851 3 0 5,151 17 0
Estuarine System.
Bottlenose dolphin........................ Southern Georgia Estuarine 1 0 0 1 0 0
System.
Tamanend's bottlenose dolphin............. Western North Atlantic 2,797 1 0 16,626 4 0
Central Florida Coastal.
Tamanend's bottlenose dolphin............. Western North Atlantic 4,382 3 0 26,243 9 0
Northern Florida Coastal.
Bottlenose dolphin........................ Western North Atlantic 6,236 26 0 37,917 148 0
Northern Migratory Coastal.
Bottlenose dolphin........................ Western North Atlantic 66,789 76 1 427,270 504 1
Offshore.
Tamanend's bottlenose dolphin............. Western North Atlantic South 1,092 3 0 6,372 11 0
Carolina/Georgia Coastal.
Bottlenose dolphin........................ Western North Atlantic 1,015 2 0 5,874 8 0
Southern Migratory Coastal.
Clymene dolphin........................... Western North Atlantic...... 63,262 89 0 416,118 604 0
False killer whale........................ Western North Atlantic...... 165 1 0 1,050 1 0
Fraser's dolphin.......................... Western North Atlantic...... 1,000 1 0 6,602 6 0
Killer whale.............................. Western North Atlantic...... 69 1 0 435 1 0
Long-finned pilot whale................... Western North Atlantic...... 8,177 7 0 51,507 45 0
Melon-headed whale........................ Western North Atlantic...... 1,078 2 0 7,099 10 0
Pantropical spotted dolphin............... Western North Atlantic...... 2,087 2 0 13,525 13 0
Pygmy killer whale........................ Western North Atlantic...... 108 0 0 712 0 0
Risso's dolphin........................... Western North Atlantic...... 15,103 20 0 95,004 119 0
Rough-toothed dolphin..................... Western North Atlantic...... 1,386 3 0 8,901 15 0
Short-finned pilot whale.................. Western North Atlantic...... 11,275 12 0 72,834 73 0
Spinner dolphin........................... Western North Atlantic...... 1,168 1 0 7,536 7 0
Striped dolphin........................... Western North Atlantic...... 87,521 137 0 548,894 931 0
White-beaked dolphin...................... Western North Atlantic...... 12 0 0 76 0 0
Harbor porpoise........................... Gulf of Maine/Bay of Fundy.. 50,625 70 0 332,156 421 0
Gray seal................................. Western North Atlantic...... 7,813 10 0 50,645 58 0
Harbor seal............................... Western North Atlantic...... 10,813 13 0 70,072 78 0
Harp seal................................. Western North Atlantic...... 11,156 3 0 72,257 15 0
Hooded seal............................... Western North Atlantic...... 1,264 1 0 7,777 4 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: All Navy Testing estimated mortalities are due to ship shock trials without consideration of extensive mitigation measures

Table 37--Incidental Take Estimate by Stock Due to Acoustic and Explosive Sources During Coast Guard Training Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Maximum
annual annual Maximum 7-Year total 7-Year total 7-Year total
Species Stock Level B Level A annual Level B Level A mortality
harassment harassment mortality harassment harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale................ Western..................... 1 0 0 4 0 0
Fin whale................................. Western North Atlantic...... 3 0 0 3 0 0
Humpback whale............................ Gulf of Maine............... 3 0 0 7 0 0
Minke whale............................... Canadian East Coast......... 5 0 0 14 0 0
Rice's whale.............................. Northern Gulf of America.... 1 0 0 1 0 0
Sei whale................................. Nova Scotia................. 2 0 0 2 0 0
Sperm whale............................... North Atlantic.............. 6 0 0 36 0 0
Dwarf sperm whale......................... Northern Gulf of America.... 2 0 0 2 0 0
Pygmy sperm whale......................... Northern Gulf of America.... 2 0 0 2 0 0
Dwarf sperm whale......................... Western North Atlantic...... 8 1 0 45 1 0
Pygmy sperm whale......................... Western North Atlantic...... 6 1 0 31 1 0
Blainville's beaked whale................. Western North Atlantic...... 7 0 0 46 0 0
Goose-beaked whale........................ Western North Atlantic...... 42 0 0 277 0 0
Gervais' beaked whale..................... Western North Atlantic...... 7 0 0 45 0 0
Sowerby's beaked whale.................... Western North Atlantic...... 6 0 0 37 0 0
True's beaked whale....................... Western North Atlantic...... 6 0 0 39 0 0
Atlantic spotted dolphin.................. Northern Gulf of America.... 36 0 0 241 0 0
Bottlenose dolphin........................ Gulf of America Oceanic..... 2 0 0 3 0 0
Bottlenose dolphin........................ Northern Gulf of America 85 1 0 585 1 0
Continental Shelf.
Rough-toothed dolphin..................... Northern Gulf of America.... 4 0 0 22 0 0
Atlantic white-sided dolphin.............. Western North Atlantic...... 6 0 0 27 0 0
Common dolphin............................ Western North Atlantic...... 19 1 0 127 1 0
Atlantic spotted dolphin.................. Western North Atlantic...... 32 0 0 205 0 0
Bottlenose dolphin........................ Northern North Carolina 500 0 0 3,494 0 0
Estuarine System.
Tamanend's bottlenose dolphin............. Western North Atlantic 5 0 0 30 0 0
Central Florida Coastal.

[[Page 19970]]

Bottlenose dolphin........................ Western North Atlantic 2,772 0 0 19,400 0 0
Northern Migratory Coastal.
Bottlenose dolphin........................ Western North Atlantic 106 0 0 723 0 0
Offshore.
Tamanend's bottlenose dolphin............. Western North Atlantic South 1 0 0 1 0 0
Carolina/Georgia Coastal.
Bottlenose dolphin........................ Western North Atlantic 297 0 0 2,076 0 0
Southern Migratory Coastal.
Clymene dolphin........................... Western North Atlantic...... 1 0 0 1 0 0
False killer whale........................ Western North Atlantic...... 1 0 0 1 0 0
Fraser's dolphin.......................... Western North Atlantic...... 1 0 0 7 0 0
Killer whale.............................. Western North Atlantic...... 1 0 0 1 0 0
Long-finned pilot whale................... Western North Atlantic...... 2 0 0 3 0 0
Melon-headed whale........................ Western North Atlantic...... 3 0 0 19 0 0
Pantropical spotted dolphin............... Western North Atlantic...... 5 0 0 29 0 0
Pygmy killer whale........................ Western North Atlantic...... 1 0 0 2 0 0
Risso's dolphin........................... Western North Atlantic...... 8 0 0 43 0 0
Rough-toothed dolphin..................... Western North Atlantic...... 2 0 0 14 0 0
Short-finned pilot whale.................. Western North Atlantic...... 15 0 0 93 0 0
Spinner dolphin........................... Western North Atlantic...... 3 0 0 15 0 0
Striped dolphin........................... Western North Atlantic...... 2 0 0 4 0 0
Harbor porpoise........................... Gulf of Maine/Bay of Fundy.. 98 4 0 677 28 0
Gray seal................................. Western North Atlantic...... 49 0 0 342 0 0
Harbor seal............................... Western North Atlantic...... 74 1 0 500 1 0
Harp seal................................. Western North Atlantic...... 4 1 0 27 1 0
Hooded seal............................... Western North Atlantic...... 2 0 0 3 0 0
--------------------------------------------------------------------------------------------------------------------------------------------------------

Estimated Take From Sonar and Other Transducers
Table 38, table 39, and table 40 provide estimated effects from
sonar and other transducers, including the comparative amounts of TTS
and behavioral disturbance for each species and stock annually, noting
that if a modeled marine mammal was ``taken'' through exposure to both
TTS and behavioral disturbance in the model, it was recorded as a TTS.
Of note, a higher proportion of the takes by Level B harassment of
mysticetes include the potential for TTS (as compared to other taxa and
prior rules) due to a combination of the fact that mysticetes are
relatively less sensitive to behavioral disturbance and the number of
auditory impacts from sonar (both TTS and AUD INJ) have increased for
some species since the Phase III analysis (84 FR 70712, December 23,
2019) largely due to changes in how avoidance was modeled; for some
stocks, changes in densities in areas that overlap activities have also
contributed to increased or decreased impacts compared to those modeled
in Phase III.
Additionally, although the Navy proposes to use substantially fewer
hours of hull-mounted sonars in this action compared to the Phase III
analysis, the updated HF cetacean criteria reflect greater
susceptibility to auditory effects at low and mid-frequencies than
previously analyzed. Consequently, the predicted auditory effects due
to sources under 10 kHz, including but not limited to MF1 hull-mounted
sonar and other anti-submarine warfare sonars, are substantially higher
for this auditory group than in prior analyses of the same activities.
Thus, for activities with sonars, some modeled exposures that would
previously have been categorized as significant behavioral responses
may now instead be counted as auditory effects (TTS and AUD INJ).
Similarly, the updated HF cetacean criteria reflect greater
susceptibility to auditory effects at low and mid-frequencies in
impulsive sounds. For VHF cetaceans, susceptibility to auditory effects
has not changed substantially since the prior analysis.

Table 38--Annual and 7-Year Estimated Take of Marine Mammal Stocks From Sonar and Other Active Transducers During Navy Training Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Maximum Maximum 7- Maximum 7-
Species Stock annual Maximum annual AUD year Maximum 7- year AUD
behavioral annual TTS INJ behavioral year TTS INJ
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale.................... Western......................... 17 56 1 113 370 2
Blue whale.................................... Western North Atlantic.......... 6 32 0 42 220 0
Bryde's whale................................. Primary......................... 1 9 - 6 63 -
Fin whale..................................... Western North Atlantic.......... 218 833 6 1,520 5,810 38
Humpback whale................................ Gulf of Maine................... 56 264 6 387 1,827 40
Minke whale................................... Canadian East Coast............. 239 2,332 17 1,665 15,771 113
Rice's whale.................................. Northern Gulf of America........ 1 6 1 7 41 1
Sei whale..................................... Nova Scotia..................... 38 313 3 264 2,136 17
Sperm whale................................... North Atlantic.................. 5,692 1,487 1 39,824 10,380 1
Sperm whale................................... Northern Gulf of America........ 32 4 - 224 28 -
Dwarf sperm whale............................. Northern Gulf of America........ 2 8 0 14 55 0
Pygmy sperm whale............................. Northern Gulf of America........ 2 9 1 14 61 1
Dwarf sperm whale............................. Western North Atlantic.......... 743 2,875 25 5,191 19,945 174
Pygmy sperm whale............................. Western North Atlantic.......... 774 2,792 25 5,409 19,359 171
Blainville's beaked whale..................... Northern Gulf of America........ 12 0 - 79 0 -
Goose-beaked whale............................ Northern Gulf of America........ 40 1 - 280 1 -
Gervais' beaked whale......................... Northern Gulf of America........ 13 1 - 89 1 -

[[Page 19971]]

Blainville's beaked whale..................... Western North Atlantic.......... 15,211 53 - 106,367 371 -
Goose-beaked whale............................ Western North Atlantic.......... 65,767 234 - 459,656 1,636 -
Gervais' beaked whale......................... Western North Atlantic.......... 15,616 143 - 109,195 999 -
Northern bottlenose whale..................... Western North Atlantic.......... 824 4 - 5,765 24 -
Sowerby's beaked whale........................ Western North Atlantic.......... 15,679 165 - 109,639 1,153 -
True's beaked whale........................... Western North Atlantic.......... 15,721 169 - 109,931 1,178 -
Atlantic spotted dolphin...................... Northern Gulf of America........ 508 280 0 3,544 1,948 0
Bottlenose dolphin............................ Gulf of America Eastern Coastal. 27 - - 115 - -
Bottlenose dolphin............................ Gulf of America Northern Coastal 197 - - 1,379 - -
Bottlenose dolphin............................ Gulf of America Oceanic......... 432 83 1 3,024 580 1
Bottlenose dolphin............................ Gulf of America Western Coastal. 359 432 - 1,076 1,296 -
Bottlenose dolphin............................ Northern Gulf of America 4,268 364 0 29,367 2,365 0
Continental Shelf.
Bottlenose dolphin............................ Nueces and Corpus Christi Bays.. 4 - - 11 - -
Bottlenose dolphin............................ Sabine Lake..................... 1 - - 2 - -
Bottlenose dolphin............................ St. Andrew Bay.................. 14 - - 92 - -
Bottlenose dolphin............................ St. Joseph Bay.................. 7 - - 47 - -
Bottlenose dolphin............................ Tampa Bay....................... 163 187 - 490 560 -
Clymene dolphin............................... Northern Gulf of America........ 35 31 0 242 217 0
False killer whale............................ Northern Gulf of America........ 15 9 - 99 61 -
Fraser's dolphin.............................. Northern Gulf of America........ 17 6 - 119 38 -
Killer whale.................................. Northern Gulf of America........ 8 5 - 51 31 -
Melon-headed whale............................ Northern Gulf of America........ 53 28 - 366 195 -
Pygmy killer whale............................ Northern Gulf of America........ 18 11 - 125 73 -
Risso's dolphin............................... Northern Gulf of America........ 16 7 0 109 46 0
Rough-toothed dolphin......................... Northern Gulf of America........ 89 37 - 617 245 -
Short-finned pilot whale...................... Northern Gulf of America........ 54 33 0 377 231 0
Striped dolphin............................... Northern Gulf of America........ 186 57 0 1,300 394 0
Pantropical spotted dolphin................... Northern Gulf of America........ 498 220 1 3,486 1,538 1
Spinner dolphin............................... Northern Gulf of America........ 12 8 0 80 55 0
Atlantic white-sided dolphin.................. Western North Atlantic.......... 2,051 1,172 2 14,333 8,190 8
Common dolphin................................ Western North Atlantic.......... 83,926 81,845 33 587,262 572,658 228
Atlantic spotted dolphin...................... Western North Atlantic.......... 34,866 39,711 22 241,359 266,255 151
Bottlenose dolphin............................ Indian River Lagoon Estuarine 1,421 1 0 9,598 3 0
System.
Bottlenose dolphin............................ Jacksonville Estuarine System... 264 84 - 1,825 583 -
Bottlenose dolphin............................ Northern Georgia/Southern South 2 - - 6 - -
Carolina Estuarine System.
Bottlenose dolphin............................ Northern North Carolina 7,653 1,527 3 53,027 10,363 20
Estuarine System.
Bottlenose dolphin............................ Southern Georgia Estuarine 84 38 1 498 212 1
System.
Bottlenose dolphin............................ Southern North Carolina 81 80 - 255 279 -
Estuarine System.
Tamanend's bottlenose dolphin................. Western North Atlantic Central 6,517 1,157 0 44,348 5,270 0
Florida Coastal.
Tamanend's bottlenose dolphin................. Western North Atlantic Northern 15,287 1,711 1 106,216 10,461 3
Florida Coastal.
Bottlenose dolphin............................ Western North Atlantic Northern 52,040 12,610 28 363,648 86,215 196
Migratory Coastal.
Bottlenose dolphin............................ Western North Atlantic Offshore. 62,316 57,732 20 431,069 386,677 131
Tamanend's bottlenose dolphin................. Western North Atlantic South 1,172 2,685 2 7,399 16,942 8
Carolina/Georgia Coastal.
Bottlenose dolphin............................ Western North Atlantic Southern 2,345 6,475 2 15,085 41,513 14
Migratory Coastal.
Clymene dolphin............................... Western North Atlantic.......... 39,694 29,729 8 277,855 208,097 54
False killer whale............................ Western North Atlantic.......... 236 170 - 1,647 1,174 -
Fraser's dolphin.............................. Western North Atlantic.......... 1,000 902 1 6,872 5,948 6
Killer whale.................................. Western North Atlantic.......... 68 42 0 476 283 0
Long-finned pilot whale....................... Western North Atlantic.......... 8,540 4,954 2 59,774 34,676 8
Melon-headed whale............................ Western North Atlantic.......... 1,684 1,833 1 11,682 12,286 2
Pantropical spotted dolphin................... Western North Atlantic.......... 5,641 5,332 2 39,262 36,344 11
Pygmy killer whale............................ Western North Atlantic.......... 185 183 0 1,283 1,229 0
Risso's dolphin............................... Western North Atlantic.......... 12,425 9,694 3 86,042 64,728 21
Rough-toothed dolphin......................... Western North Atlantic.......... 1,444 1,917 2 9,949 12,681 9
Short-finned pilot whale...................... Western North Atlantic.......... 12,319 9,414 2 85,503 63,500 11
Spinner dolphin............................... Western North Atlantic.......... 2,193 1,991 1 15,284 13,673 3
Striped dolphin............................... Western North Atlantic.......... 69,973 51,282 22 489,808 358,968 153
White-beaked dolphin.......................... Western North Atlantic.......... 3 1 - 20 7 -
Harbor porpoise............................... Gulf of Maine/Bay of Fundy...... 34,065 2,022 6 237,737 14,003 41
Gray seal..................................... Western North Atlantic.......... 5,241 2,531 11 36,379 17,593 73
Harbor seal................................... Western North Atlantic.......... 7,331 3,737 14 51,139 25,808 97
Harp seal..................................... Western North Atlantic.......... 7,813 6,819 2 54,673 47,692 12
Hooded seal................................... Western North Atlantic.......... 343 117 1 2,397 808 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Zero (0) impacts indicate total less than 0.5 and a dash (-) is a true zero. In some cases where the estimated take within a cell is equal to 1,
that value has been rounded up from a value that is less than 0.5 to avoid underestimating potential impacts to a species or stock based on the 7-year
rounding rules discussed in Section 2.4 of Appendix E (Acoustic and Explosive Impacts Analysis) of the 2024 AFTT Draft Supplemental EIS/OEIS.

[[Page 19972]]

Table 39--Annual and 7-Year Estimated Take of Marine Mammal Stocks From Sonar and Other Active Transducers During Navy Testing Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Maximum Maximum 7- Maximum 7-
Species Stock annual Maximum annual AUD year Maximum 7- year AUD
behavioral annual TTS INJ behavioral year TTS INJ
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale.................... Western......................... 71 236 1 471 1,511 6
Blue whale.................................... Western North Atlantic.......... 4 25 1 27 167 2
Bryde's whale................................. Primary......................... 1 - - 1 - -
Fin whale..................................... Western North Atlantic.......... 328 1,010 12 2,128 6,469 76
Humpback whale................................ Gulf of Maine................... 127 353 5 836 2,227 33
Minke whale................................... Canadian East Coast............. 401 1,575 37 2,631 10,399 253
Rice's whale.................................. Northern Gulf of America........ 79 204 1 536 1,387 4
Sei whale..................................... Nova Scotia..................... 75 305 4 489 2,003 27
Sperm whale................................... North Atlantic.................. 3,174 2,218 3 19,302 15,058 15
Sperm whale................................... Northern Gulf of America........ 214 21 - 1,281 116 -
Dwarf sperm whale............................. Northern Gulf of America........ 19 124 5 112 820 32
Pygmy sperm whale............................. Northern Gulf of America........ 20 106 4 122 693 23
Dwarf sperm whale............................. Western North Atlantic.......... 521 2,076 139 3,205 13,540 937
Pygmy sperm whale............................. Western North Atlantic.......... 525 2,095 132 3,226 13,665 892
Blainville's beaked whale..................... Northern Gulf of America........ 114 0 - 733 0 -
Goose-beaked whale............................ Northern Gulf of America........ 417 1 - 2,679 1 -
Gervais' beaked whale......................... Northern Gulf of America........ 110 0 - 709 0 -
Blainville's beaked whale..................... Western North Atlantic.......... 10,331 98 0 65,116 672 0
Goose-beaked whale............................ Western North Atlantic.......... 45,642 373 0 288,385 2,556 0
Gervais' beaked whale......................... Western North Atlantic.......... 9,485 191 - 60,788 1,306 -
Northern bottlenose whale..................... Western North Atlantic.......... 817 5 - 5,056 33 -
Sowerby's beaked whale........................ Western North Atlantic.......... 9,570 198 - 61,349 1,351 -
True's beaked whale........................... Western North Atlantic.......... 9,488 194 - 60,825 1,324 -
Atlantic spotted dolphin...................... Northern Gulf of America........ 6,523 5,425 18 42,782 35,096 113
Bottlenose dolphin............................ Gulf of America Eastern Coastal. 47 3 - 314 14 -
Bottlenose dolphin............................ Gulf of America Northern Coastal 4,346 503 - 30,370 3,519 -
Bottlenose dolphin............................ Gulf of America Oceanic......... 4,326 1,425 2 27,878 9,070 8
Bottlenose dolphin............................ Gulf of America Western Coastal. 1,412 1,125 - 8,760 6,977 -
Bottlenose dolphin............................ Mississippi Sound, Lake Borgne, 151 43 1 832 238 1
and Bay Boudreau.
Bottlenose dolphin............................ Northern Gulf of America 42,067 23,967 21 288,739 156,296 132
Continental Shelf.
Bottlenose dolphin............................ St. Andrew Bay.................. 30 0 0 209 0 0
Bottlenose dolphin............................ St. Joseph Bay.................. 35 - - 240 - -
Clymene dolphin............................... Northern Gulf of America........ 354 177 1 2,062 1,049 2
False killer whale............................ Northern Gulf of America........ 152 52 0 936 325 0
Fraser's dolphin.............................. Northern Gulf of America........ 150 66 0 911 417 0
Killer whale.................................. Northern Gulf of America........ 76 21 0 470 128 0
Melon-headed whale............................ Northern Gulf of America........ 525 163 1 3,233 1,008 1
Pygmy killer whale............................ Northern Gulf of America........ 185 69 0 1,137 436 0
Risso's dolphin............................... Northern Gulf of America........ 138 40 0 857 238 0
Rough-toothed dolphin......................... Northern Gulf of America........ 888 612 1 5,852 4,008 3
Short-finned pilot whale...................... Northern Gulf of America........ 574 357 2 3,391 2,176 12
Striped dolphin............................... Northern Gulf of America........ 1,541 580 0 9,961 3,725 0
Pantropical spotted dolphin................... Northern Gulf of America........ 4,088 1,495 2 25,521 9,358 12
Spinner dolphin............................... Northern Gulf of America........ 466 169 - 3,161 1,162 -
Atlantic white-sided dolphin.................. Western North Atlantic.......... 5,106 2,547 4 32,124 16,876 24
Common dolphin................................ Western North Atlantic.......... 52,543 50,344 100 334,319 321,736 634
Atlantic spotted dolphin...................... Western North Atlantic.......... 16,870 29,186 56 101,954 186,189 381
Bottlenose dolphin............................ Indian River Lagoon Estuarine 17 137 0 119 955 0
System.
Bottlenose dolphin............................ Jacksonville Estuarine System... 5 7 0 30 39 0
Bottlenose dolphin............................ Northern North Carolina 436 415 3 2,607 2,544 17
Estuarine System.
Bottlenose dolphin............................ Southern Georgia Estuarine 1 - - 1 - -
System.
Tamanend's bottlenose dolphin................. Western North Atlantic Central 1,377 1,403 0 8,277 8,253 0
Florida Coastal.
Tamanend's bottlenose dolphin................. Western North Atlantic Northern 1,761 2,616 2 10,598 15,617 8
Florida Coastal.
Bottlenose dolphin............................ Western North Atlantic Northern 2,442 3,790 25 14,480 23,416 147
Migratory Coastal.
Bottlenose dolphin............................ Western North Atlantic Offshore. 28,717 37,950 69 176,788 249,785 470
Tamanend's bottlenose dolphin................. Western North Atlantic South 239 841 2 1,483 4,817 8
Carolina/Georgia Coastal.
Bottlenose dolphin............................ Western North Atlantic Southern 269 734 1 1,664 4,137 6
Migratory Coastal.
Clymene dolphin............................... Western North Atlantic.......... 20,507 42,746 87 125,318 290,746 599
False killer whale............................ Western North Atlantic.......... 80 84 1 495 554 1
Fraser's dolphin.............................. Western North Atlantic.......... 359 638 1 2,249 4,345 6
Killer whale.................................. Western North Atlantic.......... 30 37 1 180 252 1
Long-finned pilot whale....................... Western North Atlantic.......... 4,220 3,929 6 25,633 25,706 41
Melon-headed whale............................ Western North Atlantic.......... 305 772 2 1,841 5,257 10
Pantropical spotted dolphin................... Western North Atlantic.......... 788 1,299 2 4,970 8,555 13
Pygmy killer whale............................ Western North Atlantic.......... 30 77 0 186 525 0
Risso's dolphin............................... Western North Atlantic.......... 7,772 7,293 16 46,827 47,956 103
Rough-toothed dolphin......................... Western North Atlantic.......... 425 959 3 2,546 6,351 15
Short-finned pilot whale...................... Western North Atlantic.......... 4,625 6,626 10 28,176 44,522 64
Spinner dolphin............................... Western North Atlantic.......... 410 757 1 2,487 5,047 7
Striped dolphin............................... Western North Atlantic.......... 37,593 49,900 134 218,185 330,534 918
White-beaked dolphin.......................... Western North Atlantic.......... 7 5 - 44 32 -
Harbor porpoise............................... Gulf of Maine/Bay of Fundy...... 46,821 3,627 48 307,933 23,099 297
Gray seal..................................... Western North Atlantic.......... 4,438 3,318 8 29,334 20,924 48

[[Page 19973]]

Harbor seal................................... Western North Atlantic.......... 5,878 4,858 11 38,909 30,640 67
Harp seal..................................... Western North Atlantic.......... 8,808 2,327 2 56,816 15,303 11
Hooded seal................................... Western North Atlantic.......... 735 527 1 4,337 3,432 4
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Zero (0) impacts indicate total less than 0.5 and a dash (-) is a true zero. In some cases where the estimated take within a cell is equal to 1,
that value has been rounded up from a value that is less than 0.5 to avoid underestimating potential impacts to a species or stock based on the 7-year
rounding rules discussed in Section 2.4 of Appendix E (Acoustic and Explosive Impacts Analysis) of the 2024 AFTT Draft Supplemental EIS/OEIS.

Table 40--Annual and 7-Year Estimated Take of Marine Mammal Stocks From Sonar and Other Active Transducers During Coast Guard Training Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Maximum Maximum 7- Maximum 7-
Species Stock annual Maximum annual AUD year Maximum 7- year AUD
behavioral annual TTS INJ behavioral year TTS INJ
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale.................... Western......................... 1 - - 4 - -
Fin whale..................................... Western North Atlantic.......... 1 - - 1 - -
Humpback whale................................ Gulf of Maine................... 1 - - 4 - -
Minke whale................................... Canadian East Coast............. 2 1 - 11 1 -
Rice's whale.................................. Northern Gulf of America........ 1 - - 1 - -
Sei whale..................................... Nova Scotia..................... 1 - - 1 - -
Sperm whale................................... North Atlantic.................. 5 - - 35 - -
Dwarf sperm whale............................. Western North Atlantic.......... 2 4 - 10 23 -
Pygmy sperm whale............................. Western North Atlantic.......... 2 2 - 10 11 -
Blainville's beaked whale..................... Western North Atlantic.......... 7 - - 46 - -
Goose-beaked whale............................ Western North Atlantic.......... 40 - - 275 - -
Gervais' beaked whale......................... Western North Atlantic.......... 7 - - 45 - -
Sowerby's beaked whale........................ Western North Atlantic.......... 6 - - 37 - -
True's beaked whale........................... Western North Atlantic.......... 6 - - 39 - -
Atlantic spotted dolphin...................... Northern Gulf of America........ 35 - - 239 - -
Bottlenose dolphin............................ Gulf of America Oceanic......... 1 - - 2 - -
Bottlenose dolphin............................ Northern Gulf of America 78 - - 542 - -
Continental Shelf.
Rough-toothed dolphin......................... Northern Gulf of America........ 4 - - 22 - -
Atlantic white-sided dolphin.................. Western North Atlantic.......... 3 - - 16 - -
Common dolphin................................ Western North Atlantic.......... 13 - - 91 - -
Atlantic spotted dolphin...................... Western North Atlantic.......... 29 1 - 200 2 -
Bottlenose dolphin............................ Northern North Carolina 489 11 - 3,423 71 -
Estuarine System.
Tamanend's bottlenose dolphin................. Western North Atlantic Central 5 - - 30 - -
Florida Coastal.
Bottlenose dolphin............................ Western North Atlantic Northern 2,712 60 - 18,984 416 -
Migratory Coastal.
Bottlenose dolphin............................ Western North Atlantic Offshore. 103 1 - 716 1 -
Tamanend's bottlenose dolphin................. Western North Atlantic South 1 - - 1 - -
Carolina/Georgia Coastal.
Bottlenose dolphin............................ Western North Atlantic Southern 294 3 - 2,056 20 -
Migratory Coastal.
Clymene dolphin............................... Western North Atlantic.......... 1 - - 1 - -
False killer whale............................ Western North Atlantic.......... 1 - - 1 - -
Fraser's dolphin.............................. Western North Atlantic.......... 1 - - 7 - -
Killer whale.................................. Western North Atlantic.......... 1 - - 1 - -
Melon-headed whale............................ Western North Atlantic.......... 3 - - 19 - -
Pantropical spotted dolphin................... Western North Atlantic.......... 5 - - 29 - -
Pygmy killer whale............................ Western North Atlantic.......... 1 - - 2 - -
Risso's dolphin............................... Western North Atlantic.......... 6 - - 41 - -
Rough-toothed dolphin......................... Western North Atlantic.......... 2 - - 14 - -
Short-finned pilot whale...................... Western North Atlantic.......... 13 0 - 91 0 -
Spinner dolphin............................... Western North Atlantic.......... 3 - - 15 - -
Harbor porpoise............................... Gulf of Maine/Bay of Fundy...... 46 6 - 321 40 -
Gray seal..................................... Western North Atlantic.......... 46 1 - 322 7 -
Harbor seal................................... Western North Atlantic.......... 68 2 - 474 8 -
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Zero (0) impacts indicate total less than 0.5 and a dash (-) is a true zero. In some cases where the estimated take within a cell is equal to 1,
that value has been rounded up from a value that is less than 0.5 to avoid underestimating potential impacts to a species or stock based on the 7-year
rounding rules discussed in Section 2.4 of Appendix E (Acoustic and Explosive Impacts Analysis) of the 2024 AFTT Draft Supplemental EIS/OEIS.

Estimated Take From Air Guns and Pile Driving
Table 41 provides estimated effects from air guns, including the
comparative amounts of TTS and behavioral disturbance for each species
and stock annually, noting that if a modeled marine mammal was
``taken'' through exposure to both TTS and behavioral disturbance in
the model, it was recorded as a TTS.

[[Page 19974]]

Table 41--Annual and 7-Year Estimated Take of Marine Mammal Stocks From Air Guns During Navy Testing Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Maximum Maximum 7- Maximum 7-
Species Stock annual Maximum annual AUD year Maximum 7- year AUD
behavioral annual TTS INJ behavioral year TTS INJ
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin whale.................................. Western North Atlantic....... 1 - - 1 - -
Dwarf sperm whale.......................... Northern Gulf of America..... 1 - - 1 - -
Dwarf sperm whale.......................... Western North Atlantic....... 1 1 0 3 2 0
Pygmy sperm whale.......................... Western North Atlantic....... 1 1 - 2 4 -
Bottlenose dolphin......................... Northern Gulf of America 1 0 - 1 0 -
Continental Shelf.
Common dolphin............................. Western North Atlantic....... 1 - - 4 - -
Bottlenose dolphin......................... Western North Atlantic 1 - - 1 - -
Offshore.
Striped dolphin............................ Western North Atlantic....... 1 - - 2 - -
Harbor porpoise............................ Gulf of Maine/Bay of Fundy... 2 3 1 12 15 1
Gray seal.................................. Western North Atlantic....... 1 0 - 7 0 -
Harbor seal................................ Western North Atlantic....... 1 0 - 5 0 -
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Zero (0) impacts indicate total less than 0.5 and a dash (-) is a true zero. In some cases where the estimated take within a cell is equal to 1,
that value has been rounded up from a value that is less than 0.5 to avoid underestimating potential impacts to a species or stock based on the 7-year
rounding rules discussed in Section 2.4 of Appendix E (Acoustic and Explosive Impacts Analysis) of the 2024 AFTT Draft Supplemental EIS/OEIS.

Table 42 provides the estimated effects from pile driving and
extraction, including the comparative amounts of TTS and behavioral
disturbance for each species and stock annually, noting that if a
modeled marine mammal was ``taken'' through exposure to both TTS and
behavioral disturbance in the model, it was recorded as a TTS.

Table 42--Annual and 7-Year Estimated Take of Marine Mammal Stocks From Pile Driving During Navy Training Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Maximum Maximum 7- Maximum 7-
Species Stock annual Maximum annual AUD year Maximum 7- year AUD
behavioral annual TTS INJ behavioral year TTS INJ
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bottlenose dolphin......................... Gulf of America Northern 1,894 0 - 13,255 0 -
Coastal.
Bottlenose dolphin......................... Mississippi Sound, Lake 1,564 0 - 10,944 0 -
Borgne, and Bay Boudreau.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Zero (0) impacts indicate total less than 0.5 and a dash (-) is a true zero.

Estimated Take From Explosives
Table 43 provides estimated effects from explosives during Navy
training activities and table 44 provides estimated effects from
explosives including small ship shock trials from Navy testing
activities. Table 45 provides estimated effects from small ship shock
trials over a maximum year (two events) of Navy testing activities,
which is a subset of the information included in table 44. Table 46
provides estimated effects from explosives during Coast Guard training
activities.

[[Page 19975]]

Table 43--Annual and 7-Year Estimated Take of Marine Mammal Stocks From Explosives During Navy Training Activities
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Maximum
Maximum Maximum Maximum annual Maximum Maximum 7- Maximum Maximum 7-year Maximum
Species Stock annual annual annual non- annual year 7-year 7-year non- 7-year
behavioral TTS AUD INJ auditory mortality behavioral TTS AUD INJ auditory mortality
injury injury
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale.................. Western....................... 14 10 0 - - 93 66 0 - -
Blue whale.................................. Western North Atlantic........ 1 1 - - - 2 1 - - -
Fin whale................................... Western North Atlantic........ 30 8 0 - - 205 50 0 - -
Humpback whale.............................. Gulf of Maine................. 14 7 1 - - 94 43 1 - -
Minke whale................................. Canadian East Coast........... 24 11 1 - - 167 73 7 - -
Rice's whale................................ Northern Gulf of America...... 0 1 - - - 0 1 - - -
Sei whale................................... Nova Scotia................... 4 1 0 - - 27 3 0 - -
Sperm whale................................. North Atlantic................ 4 6 1 1 - 26 36 3 1 -
Sperm whale................................. Northern Gulf of America...... 1 1 0 - - 1 1 0 - -
Dwarf sperm whale........................... Northern Gulf of America...... 2 2 1 0 - 8 10 1 0 -
Pygmy sperm whale........................... Northern Gulf of America...... 2 2 1 - - 9 12 1 - -
Dwarf sperm whale........................... Western North Atlantic........ 27 33 7 - - 188 227 47 - -
Pygmy sperm whale........................... Western North Atlantic........ 26 33 9 - - 182 225 60 - -
Blainville's beaked whale................... Western North Atlantic........ 1 2 1 - - 5 8 1 - -
Goose-beaked whale.......................... Western North Atlantic........ 6 4 1 - - 36 28 3 - -
Gervais' beaked whale....................... Western North Atlantic........ 1 1 - - - 1 3 - - -
Sowerby's beaked whale...................... Western North Atlantic........ 1 1 0 - - 7 5 0 - -
True's beaked whale......................... Western North Atlantic........ 1 1 0 - - 1 1 0 - -
Atlantic spotted dolphin.................... Northern Gulf of America...... 1 3 1 0 - 4 19 4 0 -
Bottlenose dolphin.......................... Gulf of America Eastern 1 1 - - - 4 7 - - -
Coastal.
Bottlenose dolphin.......................... Gulf of America Northern 1 2 1 - - 3 8 2 - -
Coastal.
Bottlenose dolphin.......................... Gulf of America Oceanic....... 1 1 0 - - 3 4 0 - -
Bottlenose dolphin.......................... Northern Gulf of America 14 19 2 1 0 95 132 12 1 0
Continental Shelf.
Fraser's dolphin............................ Northern Gulf of America...... 1 1 0 - - 1 1 0 - -
Rough-toothed dolphin....................... Northern Gulf of America...... 1 1 0 - - 1 3 0 - -
Short-finned pilot whale.................... Northern Gulf of America...... 0 1 - - - 0 3 - - -
Striped dolphin............................. Northern Gulf of America...... 0 1 1 0 - 0 2 1 0 -
Pantropical spotted dolphin................. Northern Gulf of America...... 1 1 1 1 0 5 7 2 2 0
Atlantic white-sided dolphin................ Western North Atlantic........ 4 6 1 1 - 26 41 7 3 -
Common dolphin.............................. Western North Atlantic........ 50 42 5 1 - 345 288 29 4 -
Atlantic spotted dolphin.................... Western North Atlantic........ 35 37 4 1 0 245 257 23 5 0
Bottlenose dolphin.......................... Northern North Carolina 1 - - - - 1 - - - -
Estuarine System.
Bottlenose dolphin.......................... Southern North Carolina 1 - - - - 1 - - - -
Estuarine System.
Tamanend's bottlenose dolphin............... Western North Atlantic Central 10 8 1 1 - 65 53 4 2 -
Florida Coastal.
Tamanend's bottlenose dolphin............... Western North Atlantic 2 3 1 0 - 8 17 1 0 -
Northern Florida Coastal.
Bottlenose dolphin.......................... Western North Atlantic 21 41 5 1 0 147 283 30 1 0
Northern Migratory Coastal.
Bottlenose dolphin.......................... Western North Atlantic 50 53 6 1 1 347 365 39 3 1
Offshore.
Tamanend's bottlenose dolphin............... Western North Atlantic South 5 5 1 0 1 32 35 3 0 1
Carolina/Georgia Coastal.
Bottlenose dolphin.......................... Western North Atlantic 19 29 4 1 0 133 202 26 4 0
Southern Migratory Coastal.
Clymene dolphin............................. Western North Atlantic........ 16 21 6 1 1 112 141 37 3 3
Fraser's dolphin............................ Western North Atlantic........ 1 1 1 0 - 4 2 2 0 -
Long-finned pilot whale..................... Western North Atlantic........ 4 3 2 1 - 28 21 9 1 -
Pantropical spotted dolphin................. Western North Atlantic........ 2 1 1 0 0 8 6 1 0 0
Pygmy killer whale.......................... Western North Atlantic........ 0 - 1 0 - 0 - 1 0 -
Risso's dolphin............................. Western North Atlantic........ 4 5 1 1 0 28 32 2 1 0
Rough-toothed dolphin....................... Western North Atlantic........ 2 2 1 0 - 8 9 1 0 -
Short-finned pilot whale.................... Western North Atlantic........ 7 5 1 0 0 45 32 7 0 0
Spinner dolphin............................. Western North Atlantic........ 0 1 0 - - 0 5 0 - -
Striped dolphin............................. Western North Atlantic........ 11 13 3 1 0 77 87 20 5 0
Harbor porpoise............................. Gulf of Maine/Bay of Fundy.... 74 235 67 0 - 515 1,644 464 0 -
Gray seal................................... Western North Atlantic........ 46 44 3 0 - 322 304 20 0 -
Harbor seal................................. Western North Atlantic........ 72 67 4 0 - 499 468 28 0 -
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Zero (0) impacts indicate total less than 0.5 and a dash (-) is a true zero. In some cases where the estimated take within a cell is equal to 1, that value has been rounded up from a
value that is less than 0.5 to avoid underestimating potential impacts to a species or stock based on the 7-year rounding rules discussed in Section 2.4 of Appendix E (Acoustic and Explosive
Impacts Analysis) of the 2024 AFTT Draft Supplemental EIS/OEIS.

[[Page 19976]]

Table 44--Annual and 7-Year Estimated Take of Marine Mammal Stocks From Explosives During Navy Training Activities
[Includes small ship shock trials]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Maximum
Maximum Maximum Maximum annual Maximum Maximum 7- Maximum Maximum 7-year Maximum
Species Stock annual annual annual non- annual year 7-year 7-year non- 7-year
behavioral TTS AUD INJ auditory mortality behavioral TTS AUD INJ auditory mortality
injury injury
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale.................. Western....................... 6 3 0 - - 34 20 0 - -
Blue whale.................................. Western North Atlantic........ 1 1 - - - 2 3 - - -
Fin whale................................... Western North Atlantic........ 110 75 3 - - 670 442 17 - -
Humpback whale.............................. Gulf of Maine................. 13 7 0 - - 81 42 0 - -
Minke whale................................. Canadian East Coast........... 26 30 1 - - 162 124 4 - -
Rice's whale................................ Northern Gulf of America...... 7 4 1 - - 49 25 1 - -
Sei whale................................... Nova Scotia................... 6 3 0 - - 40 17 0 - -
Sperm whale................................. North Atlantic................ 2 1 1 - - 8 5 1 - -
Sperm whale................................. Northern Gulf of America...... 1 1 0 0 0 1 1 0 0 0
Dwarf sperm whale........................... Northern Gulf of America...... 2 27 16 - - 12 78 40 - -
Dwarf sperm whale........................... Western North Atlantic........ 13 28 8 0 0 82 119 25 0 0
Pygmy sperm whale........................... Northern Gulf of America...... 3 29 16 - - 17 87 40 - -
Pygmy sperm whale........................... Western North Atlantic........ 12 29 9 0 - 73 126 33 0 -
Blainville's beaked whale................... Western North Atlantic........ 1 1 0 0 - 1 1 0 0 -
Goose-beaked whale.......................... Northern Gulf of America...... 0 1 0 - - 0 1 0 - -
Gervais' beaked whale....................... Northern Gulf of America...... 0 1 - - - 0 1 - - -
Goose-beaked whale.......................... Western North Atlantic........ 1 1 1 0 0 7 6 2 0 0
Gervais' beaked whale....................... Western North Atlantic........ 1 1 1 - - 1 1 1 - -
Northern bottlenose whale................... Western North Atlantic........ 1 0 1 - - 1 0 1 - -
Sowerby's beaked whale...................... Western North Atlantic........ 1 1 1 - - 1 4 1 - -
True's beaked whale......................... Western North Atlantic........ 1 1 0 - - 1 1 0 - -
Atlantic spotted dolphin.................... Northern Gulf of America...... 17 11 1 0 0 119 74 6 0 0
Bottlenose dolphin.......................... Gulf of America Eastern - 1 0 - - - 1 0 - -
Coastal.
Bottlenose dolphin.......................... Gulf of America Northern 86 117 16 - - 601 815 112 - -
Coastal.
Bottlenose dolphin.......................... Gulf of America Oceanic....... 3 1 1 0 0 15 7 2 0 0
Bottlenose dolphin.......................... Gulf of America Western 2 1 1 0 - 10 4 1 0 -
Coastal.
Bottlenose dolphin.......................... Northern Gulf of America 369 177 3 1 0 2,577 1,234 18 1 0
Continental Shelf.
Bottlenose dolphin.......................... St. Andrew Bay................ 1 1 - - - 1 1 - - -
Clymene dolphin............................. Northern Gulf of America...... 1 1 1 1 0 4 3 1 1 0
False killer whale.......................... Northern Gulf of America...... 1 1 0 - - 1 1 0 - -
Fraser's dolphin............................ Northern Gulf of America...... 0 0 0 0 - 0 0 0 0 -
Melon-headed whale.......................... Northern Gulf of America...... 1 1 0 0 0 1 3 0 0 0
Pygmy killer whale.......................... Northern Gulf of America...... 1 1 0 0 0 1 1 0 0 0
Risso's dolphin............................. Northern Gulf of America...... 1 1 0 0 0 1 1 0 0 0
Rough-toothed dolphin....................... Northern Gulf of America...... 6 4 1 1 0 39 21 1 1 0
Short-finned pilot whale.................... Northern Gulf of America...... 1 1 1 0 0 3 2 1 0 0
Striped dolphin............................. Northern Gulf of America...... 1 10 4 2 1 5 27 9 5 2
Pantropical spotted dolphin................. Northern Gulf of America...... 2 11 2 2 2 13 31 5 6 5
Spinner dolphin............................. Northern Gulf of America...... 0 1 0 0 - 0 1 0 0 -
Atlantic white-sided dolphin................ Western North Atlantic........ 6 3 1 0 0 37 15 1 0 0
Common dolphin.............................. Western North Atlantic........ 384 251 20 1 0 2,320 1,497 118 1 0
Atlantic spotted dolphin.................... Western North Atlantic........ 39 22 3 1 0 221 119 16 1 0
Tamanend's bottlenose dolphin............... Western North Atlantic Central 12 5 1 0 0 67 29 4 0 0
Florida Coastal.
Tamanend's bottlenose dolphin............... Western North Atlantic 4 1 1 - - 21 7 1 - -
Northern Florida Coastal.
Bottlenose dolphin.......................... Western North Atlantic 2 2 1 - - 10 11 1 - -
Northern Migratory Coastal.
Bottlenose dolphin.......................... Western North Atlantic 67 54 6 1 1 396 300 31 3 1
Offshore.
Tamanend's bottlenose dolphin............... Western North Atlantic South 9 3 1 0 0 55 17 3 0 0
Carolina/Georgia Coastal.
Bottlenose dolphin.......................... Western North Atlantic 9 3 1 0 - 55 18 2 0 -
Southern Migratory Coastal.
Clymene dolphin............................. Western North Atlantic........ 5 4 1 1 0 30 24 4 1 0
False killer whale.......................... Western North Atlantic........ - 1 - - - - 1 - - -
Fraser's dolphin............................ Western North Atlantic........ 1 2 0 0 - 3 5 0 0 -
Killer whale................................ Western North Atlantic........ 1 1 0 - 0 2 1 0 - 0
Long-finned pilot whale..................... Western North Atlantic........ 18 10 1 0 0 108 60 4 0 0
Melon-headed whale.......................... Western North Atlantic........ 1 0 0 0 0 1 0 0 0 0

[[Page 19977]]

Pantropical spotted dolphin................. Western North Atlantic........ 0 0 0 0 0 0 0 0 0 0
Pygmy killer whale.......................... Western North Atlantic........ 0 1 0 - - 0 1 0 - -
Risso's dolphin............................. Western North Atlantic........ 18 20 3 1 0 116 105 15 1 0
Rough-toothed dolphin....................... Western North Atlantic........ 1 1 0 0 - 2 2 0 0 -
Short-finned pilot whale.................... Western North Atlantic........ 13 11 2 0 0 78 58 9 0 0
Spinner dolphin............................. Western North Atlantic........ 1 0 0 0 - 2 0 0 0 -
Striped dolphin............................. Western North Atlantic........ 17 10 2 1 0 109 64 12 1 0
Harbor porpoise............................. Gulf of Maine/Bay of Fundy.... 75 97 21 0 0 493 604 123 0 0
Gray seal................................... Western North Atlantic........ 38 18 2 0 - 262 118 10 0 -
Harbor seal................................. Western North Atlantic........ 54 22 2 0 0 370 148 11 0 0
Harp seal................................... Western North Atlantic........ 13 8 1 0 - 88 50 4 0 -
Hooded seal................................. Western North Atlantic........ 1 1 0 - - 4 4 0 - -
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Zero (0) impacts indicate total less than 0.5 and a dash (-) is a true zero. In some cases where the estimated take within a cell is equal to 1, that value has been rounded up from a
value that is less than 0.5 to avoid underestimating potential impacts to a species or stock based on the 7-year rounding rules discussed in Section 2.4 of Appendix E (Acoustic and Explosive
Impacts Analysis) of the 2024 AFTT Draft Supplemental EIS/OEIS.

[[Page 19978]]

Table 45--Annual Estimated Effects to Marine Mammal Stocks From Small Ship Shock Trials Over a Maximum Year of
Navy Testing
[Two events]
----------------------------------------------------------------------------------------------------------------
Maximum
Maximum Maximum annual non- Maximum
Species Stock annual annual auditory annual
TTS AUD INJ injury mortality
----------------------------------------------------------------------------------------------------------------
North Atlantic right whale.......... Western............... 1 - - -
Blue whale.......................... Western North Atlantic 1 - - -
Fin whale........................... Western North Atlantic 2 0 - -
Humpback whale...................... Gulf of Maine......... 1 - - -
Minke whale......................... Canadian East Coast... 17 1 - -
Sei whale........................... Nova Scotia........... 1 0 - -
Dwarf sperm whale................... Northern Gulf of 24 15 - -
America.
Pygmy sperm whale................... Northern Gulf of 26 15 - -
America.
Dwarf sperm whale................... Western North Atlantic 14 5 - -
Pygmy sperm whale................... Western North Atlantic 14 6 - -
Goose-beaked whale.................. Northern Gulf of 1 0 - -
America.
Gervais' beaked whale............... Northern Gulf of 1 - - -
America.
Melon-headed whale.................. Northern Gulf of 1 0 0 0
America.
Pantropical spotted dolphin......... Northern Gulf of 9 1 2 2
America.
Rough-toothed dolphin............... Northern Gulf of 1 0 1 0
America.
Short-finned pilot whale............ Northern Gulf of 1 1 0 0
America.
Striped dolphin..................... Northern Gulf of 10 3 2 1
America.
Atlantic spotted dolphin............ Western North Atlantic 1 - 1 -
Bottlenose dolphin.................. Western North Atlantic 5 1 1 1
Offshore.
Fraser's dolphin.................... Western North Atlantic 2 0 0 -
Pygmy killer whale.................. Western North Atlantic 1 - - -
Risso's dolphin..................... Western North Atlantic 4 1 1 0
Rough-toothed dolphin............... Western North Atlantic 1 - 0 -
Short-finned pilot whale............ Western North Atlantic 1 1 0 0
----------------------------------------------------------------------------------------------------------------
Note: Zero (0) impacts indicate total less than 0.5 and a dash (-) is a true zero. In some cases where the
estimated take within a cell is equal to 1, that value has been rounded up from a value that is less than 0.5
to avoid underestimating potential impacts to a species or stock based on the 7-year rounding rules discussed
in Section 2.4 of Appendix E (Acoustic and Explosive Impacts Analysis) of the 2024 AFTT Draft Supplemental EIS/
OEIS.

[[Page 19979]]

Table 46--Annual and 7-Year Estimated Take of Marine Mammal Stocks From Explosives During Coast Guard Training Activities
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Maximum
Maximum Maximum Maximum annual Maximum Maximum 7- Maximum Maximum 7-year Maximum
Species Stock annual annual annual non- annual year 7-year 7-year non- 7-year
behavioral TTS AUD INJ auditory mortality behavioral TTS AUD INJ auditory mortality
injury injury
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Fin whale................................... Western North Atlantic........ 1 1 0 - - 1 1 0 - -
Humpback whale.............................. Gulf of Maine................. 1 1 0 - - 2 1 0 - -
Minke whale................................. Canadian East Coast........... 1 1 0 - - 1 1 0 - -
Sei whale................................... Nova Scotia................... 1 0 - - - 1 0 - - -
Sperm whale................................. North Atlantic................ 1 0 - - - 1 0 - - -
Dwarf sperm whale........................... Northern Gulf of America...... 1 1 - - - 1 1 - - -
Pygmy sperm whale........................... Northern Gulf of America...... 1 1 - - - 1 1 - - -
Dwarf sperm whale........................... Western North Atlantic........ 1 1 1 - - 7 5 1 - -
Pygmy sperm whale........................... Western North Atlantic........ 1 1 1 - - 5 5 1 - -
Goose-beaked whale.......................... Western North Atlantic........ 1 1 - - - 1 1 - - -
Atlantic spotted dolphin.................... Northern Gulf of America...... 1 0 - - - 2 0 - - -
Bottlenose dolphin.......................... Gulf of America Oceanic....... 1 0 - - - 1 0 - - -
Bottlenose dolphin.......................... Northern Gulf of America 4 3 1 - - 25 18 1 - -
Continental Shelf.
Atlantic white-sided dolphin................ Western North Atlantic........ 2 1 0 - - 8 3 0 - -
Common dolphin.............................. Western North Atlantic........ 3 3 1 - - 21 15 1 - -
Atlantic spotted dolphin.................... Western North Atlantic........ 1 1 - - - 2 1 - - -
Bottlenose dolphin.......................... Western North Atlantic 1 1 - 0 - 4 2 - 0 -
Offshore.
Long-finned pilot whale..................... Western North Atlantic........ 1 1 0 - - 2 1 0 - -
Risso's dolphin............................. Western North Atlantic........ 1 1 0 - - 1 1 0 - -
Short-finned pilot whale.................... Western North Atlantic........ 1 1 0 - - 1 1 0 - -
Striped dolphin............................. Western North Atlantic........ 1 1 0 - - 3 1 0 - -
Harbor porpoise............................. Gulf of Maine/Bay of Fundy.... 22 24 4 - - 150 166 28 - -
Gray seal................................... Western North Atlantic........ 1 1 0 - - 7 6 0 - -
Harbor seal................................. Western North Atlantic........ 2 2 1 - - 10 8 1 - -
Harp seal................................... Western North Atlantic........ 2 2 1 - - 14 13 1 - -
Hooded seal................................. Western North Atlantic........ 1 1 0 - - 2 1 0 - -
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Zero (0) impacts indicate total less than 0.5 and a dash (-) is a true zero. In some cases where the estimated take within a cell is equal to 1, that value has been rounded up from a
value that is less than 0.5 to avoid underestimating potential impacts to a species or stock based on the 7-year rounding rules discussed in Section 2.4 of Appendix E (Acoustic and Explosive
Impacts Analysis) of the 2024 AFTT Draft Supplemental EIS/OEIS.

[[Page 19980]]

Estimated Take From Vessel Strike by Serious Injury or Mortality

Vessel strikes from commercial, recreational, and military vessels
are known to affect large whales and have resulted in serious injury
and fatalities to cetaceans (Abramson et al., 2011; Berman-Kowalewski
et al., 2010a; Calambokidis, 2012; Douglas et al., 2008; Laggner, 2009;
Lammers et al., 2003; Van der Hoop et al., 2013; Van der Hoop et al.,
2012). Records of vessel strikes of large whales date back to the early
17th century, and the worldwide number of vessel strikes of large
whales appears to have increased steadily during recent decades (Laist
et al., 2001; Ritter 2012).
Numerous studies of interactions between surface vessels and marine
mammals have demonstrated that free-ranging marine mammals often, but
not always (e.g., McKenna et al., 2015), engage in avoidance behavior
when surface vessels move toward them. It is not clear whether these
responses are caused by the physical presence of a surface vessel, the
underwater noise generated by the vessel, or an interaction between the
two (Amaral and Carlson, 2005; Au and Green, 2000; Bain et al., 2006;
Bauer 1986; Bejder et al., 1999; Bejder and Lusseau, 2008; Bejder et
al., 2009; Bryant et al., 1984; Corkeron, 1995; Erbe, 2002;
F[eacute]lix, 2001; Goodwin and Cotton, 2004; Greig et al., 2020;
Guilpin et al., 2020; Keen et al., 2019; Lemon et al., 2006; Lusseau,
2003; Lusseau, 2006; Magalhaes et al., 2002; Nowacek et al., 2001;
Redfern et al., 2020; Richter et al., 2003; Scheidat et al., 2004;
Simmonds, 2005; Szesciorka et al., 2019; Watkins, 1986; Williams et
al., 2002; Wursig et al., 1998). Several authors suggest that the noise
generated during motion is probably an important factor (Blane and
Jaakson, 1994; Evans et al., 1992; Evans et al., 1994). These studies
suggest that the behavioral responses of marine mammals to surface
vessels are similar to their behavioral responses to predators.
Avoidance behavior is expected to be even stronger in the subset of
instances during which the Action Proponents are conducting military
readiness activities using active sonar or explosives.
The marine mammals most vulnerable to vessel strikes are those that
spend extended periods of time at the surface in order to restore
oxygen levels within their tissues after deep dives (e.g., sperm
whales). In addition, some baleen whales seem generally unresponsive to
vessel sound, making them more susceptible to vessel strikes (Nowacek
et al., 2004). These species are primarily large, slow moving whales.
There are nine species (15 stocks) of large whales that are known to
occur within the AFTT Study Area (table 14): blue whale, Bryde's whale,
fin whale, humpback whale, minke whale, NARW, Rice's whale, sei whale,
and sperm whale.
Some researchers have suggested the relative risk of a vessel
strike can be assessed as a function of animal density and the
magnitude of vessel traffic (e.g., Fonnesbeck et al., 2008; Vanderlaan
et al., 2008). Differences among vessel types also influence the
probability of a vessel strike. The ability of any vessel to detect a
marine mammal and avoid a collision depends on a variety of factors,
including environmental conditions, vessel design, size, speed, and
ability and number of personnel observing, as well as the behavior of
the animal. Vessel speed, size, and mass are all important factors in
determining if injury or death of a marine mammal is likely due to a
vessel strike. For large vessels, speed and angle of approach can
influence the severity of a strike. Large whales also do not have to be
at the water's surface to be struck. Silber et al. (2010) found that
when a whale is below the surface (about one to two times the vessel
draft), under certain circumstances (vessel speed and location of the
whale relative to the ship's centerline), there is likely to be a
pronounced propeller suction effect. This suction effect may draw the
whale into the hull of the ship, increasing the probability of
propeller strikes.
There are some key differences between the operation of military
and non-military vessels which make the likelihood of a military vessel
striking a whale lower than some other vessels (e.g., commercial
merchant vessels). Key differences include:
Military vessels have personnel assigned to stand watch at
all times, day and night, when moving through the water (i.e., when the
vessel is underway). Watch personnel undertake extensive training and
are certified to stand watch only after demonstrating competency in all
necessary skills. While on watch, personnel employ visual search and
reporting procedures in accordance with the U.S. Navy Lookout Training
Handbook, the Coast Guard's Shipboard Lookout Manual, or civilian
equivalent.
The bridges of many military vessels are positioned closer
to the bow, offering better visibility ahead of the vessel (compared to
a commercial merchant vessel);
Military readiness activities often involve aircraft
(which can serve as part of the Lookout team), that can more readily
detect cetaceans in the vicinity of a vessel or ahead of a vessel's
present course, often before crew on the vessel would be able to detect
them;
Military vessels are generally more maneuverable than
commercial merchant vessels, and are therefore capable of changing
course more quickly in the event cetaceans are spotted in the vessel's
path;
Military vessels operate at the slowest speed practical
consistent with operational requirements. While minimum speed is
intended as a fuel conservation measure particular to a certain ship
class, secondary benefits include a better ability to detect and avoid
objects in the water, including marine mammals;
Military ships often operate within a defined area for a
period of time, in contrast to point-to-point commercial shipping over
greater distances;
The crew size on military vessels is generally larger than
merchant vessels, allowing for stationing more trained Lookouts on the
bridge. At all times when the Action Proponents' vessels are underway,
trained Lookouts and bridge navigation teams are used to detect objects
on the surface of the water ahead of the ship, including cetaceans.
Some events may have additional personnel (beyond the minimum number of
required Lookouts) who are already standing watch in or on the platform
conducting the event or additional participating platforms and would
have eyes on the water for all or part of an event. These additional
personnel serve as members of the Lookout team; and
When submerged, submarines are generally slow moving (to
avoid detection); as a result, marine mammals at depth with a submarine
are likely able to avoid collision with the submarine. When a submarine
is transiting on the surface, the Navy posts Lookouts serving the same
function as they do on surface vessels.
Vessel strike to marine mammals is not associated with any specific
military readiness activity. Rather, vessel strike is a limited and
sporadic, but possible, accidental result of military vessel movement
within the AFTT Study Area or while in transit.
Prior to 2009, there is limited information on vessel strikes from
military readiness activities in the AFTT Study Area. One known
incident of vessel strike in the AFTT Study Area occurred in 2001, when
a 505 ft (154 m) Navy vessel struck and killed a sperm whale 20 mi
(32.2 km) south of Puerto Rico (Jensen and Silber, 2004). (Of note, at
the time of the strike, the Navy still used the Vieques Naval Training
Range; activities in this area ceased in 2003, and since then, vessel
traffic has significantly decreased, and there are

[[Page 19981]]

currently no plans to increase activity in that area.) A second known
incident of vessel strike occurred in VACAPES on May 15, 2005, when a
Navy vessel was involved in a strike with ``reasonable potential'' to
have been a sperm whale.
Since 2009, there have been six recorded vessel strikes of large
whales by the Action Proponents in the AFTT Study Area: three by the
Navy and three by the Coast Guard. The Navy struck one whale in 2011
(species unknown), two whales in 2012 (species unknown), and has not
struck a large whale in the AFTT Study Area since 2012. All strikes
during this timeframe occurred in the VACAPES OPAREA: one strike in the
VACAPES Range Complex in 2011, one strike in the VACAPES Range Complex
in 2012, and one strike in the Lower Chesapeake Bay in 2012. The Coast
Guard struck two whales in 2009 (both reported as NARW), and one whale
in May 2024 (species unknown). On December 14, 2009, an 87 ft (26.5 m)
Coast Guard patrol boat traveling at a speed of 9.2 kn (17 km/hr)
struck two whales (reported as NARW) at the same time near Cape Henry,
Virginia, and observed the animals swimming away without apparent
injuries, though it is important to note that not all injuries are
evident when a whale is struck and the fate of these two NARW is
unknown. It is also important to note that not all whale strikes result
in mortality, however, given the potential for non-visible injuries,
NMFS conservatively assumes that these strikes resulted in mortality of
both whales.
In light of the key differences between the operation of military
and non-military vessels discussed above, it is highly unlikely that a
military vessel would strike any type of marine mammal without
detecting it. Specifically, Lookouts posted on or near the ship's bow
can visually detect a strike in the absence of other indications that a
strike has occurred. The Action Proponents' internal procedures and
mitigation requirements include reporting of any vessel strikes of
marine mammals, and the Action Proponents' discipline, extensive
training (not only for detecting marine mammals, but for detecting and
reporting any potential navigational obstruction), and strict chain of
command give NMFS a high level of confidence that all strikes are
reported. Accordingly, NMFS is confident that the Navy and Coast
Guard's reported strikes are accurate and appropriate for use in the
analysis.
When generally compared to mysticetes, odontocetes are more capable
of physically avoiding a vessel strike and since some species occur in
large groups, they are more easily seen when they are closer to the
water surface. The smaller size and maneuverability of dolphins, small
whales (not including large whale calves), porpoises, and pinnipeds
generally make vessel strike very unlikely. For as long as records have
been kept, neither the Navy nor the Coast Guard have any record of any
small whales or pinnipeds being struck by a vessel as a result of
military readiness activities. Over the same time period, NMFS, the
Navy, and the Coast Guard have only one record of a dolphin being
struck by a vessel as a result of Navy or Coast Guard activities. The
dolphin was accidentally struck by a Navy small boat in fall 2021 in
Saint Andrew's Pass, Florida. Other than this one reported strike of a
dolphin in 2021, NMFS has never received any reports from other LOA or
Incidental Harassment Authorization holders indicating that these
species have been struck by vessels. Worldwide vessel strike records
show little evidence of strikes of these groups or marine mammals from
the shipping sector and larger vessels (though for many species,
records do exist, e.g., West et al. 2024, Waerebeek et al., 2007, Van
Waerebeek et al., 2007), and the majority of the Action Proponents'
activities involving faster-moving vessels (that could be considered
more likely to hit a marine mammal) are located in offshore areas where
smaller delphinid, porpoise, and pinniped densities are lower.
In order to account for the accidental nature of vessel strike to
large whales in general, and the potential risk from vessel movement
within the AFTT Study Area within the 7-year period of this proposed
authorization, the Action Proponents requested incidental takes based
on probabilities derived from a Poisson distribution. A Poisson
distribution is often used to describe random occurrences when the
probability of an occurrence is small. Count data, such as cetacean
sighting data, or in this case strike data, are often described as a
Poisson or over-dispersed Poisson distribution. The Poisson
distribution was calculated using vessel strike data between 2009-2024
in the AFTT Study Area, historical at-sea days in the AFTT Study Area
for the Navy and the Coast Guard (described in detail in section 6 of
the application), and estimated potential at-sea days for both Action
Proponents during the 7-year period from 2025-2032 covered by the
requested regulations. The Navy evaluated data beginning in 2009 as
that was the start of the Navy's Marine Species Awareness Training and
adoption of additional mitigation measures to address vessel strike,
which will remain in place along with additional and modified
mitigation measures during the 7 years of this rulemaking. Navy vessel
strike data only accounts for vessels larger than 65 ft (19.8 m) and
does not include USVs/UUVs as the Navy does not yet have data on their
use in the AFTT Study Area. The Poisson vessel strike calculations do
not include any specific number of at-sea days for USVs. Historically,
the USVs used in the AFTT Study Area were equivalent to small boats.
While it is anticipated that larger USVs will begin testing in the AFTT
Study Area during the 7-year period, it was assessed that the addition
of any at-sea days associated with the limited number of medium or
large USVs being tested in AFTT would not be large enough to change the
results of the analysis. In addition, there is no historical strike
data for USVs. The analysis for the period of 2025 to 2032 is described
in detail below and in section 6.3.2 (Probability of Vessel Strike of
Large Whale Species) of the application.
Between 2009 and early 2024, there were a total of 42,748 Navy at-
sea days and 26,756 Coast Guard at-sea days in the AFTT Study Area.
During that same time, there were three Navy vessel strikes of large
whales and three Coast Guard vessel strikes of large whales. From 2025
through 2032, the Navy anticipates 18,702 at-sea days, and the Coast
Guard anticipates 11,706 at-sea days.
To calculate a vessel strike rate for each Action Proponent for the
period of 2009 through 2024, the Action Proponents used the respective
number of past vessel strikes of large whales and the respective number
of at-sea days. Navy at-sea days (for vessels greater than 65 ft (19.8
m)) from 2009 through 2024 was estimated to be 42,748 days. Dividing
the three known Navy strikes during that period by the at-sea days
(i.e., 3 strikes/42,748 at-sea days) results in a strike rate of
0.000070 strikes per at-sea day. Coast Guard at-sea days (for vessels
greater than 65 ft (19.8 m)) from 2009 through 2024 was estimated to be
26,756 days. Dividing the three known Coast Guard strikes during that
period by the at-sea days (i.e., 3 strikes/26,756 at-sea days) results
in a strike rate of 0.000112 strikes per day.
Based on the average annual at-sea days from 2009 to early 2024,
the Action Proponents estimated that 18,702 Navy and 11,706 Coast Guard
at-sea days would occur over the 7-year period associated with the
requested authorization. Given a strike rate of

[[Page 19982]]

0.000070 Navy strikes per at-sea day, and 0.000112 Coast Guard strikes
per at-sea day, the predicted number of vessel strikes over a 7-year
period would be 1.31 strikes by the Navy and 1.31 strikes by the Coast
Guard.
Using this predicted number of strikes, the Poisson distribution
predicted the probabilities of a specific number of strikes (n = 0, 1,
2, etc.) from 2025 through 2032. The probability analysis concluded
that, for each Action Proponent, there is a 27 percent chance that zero
whales would be struck by the Action Proponents' vessels over the 7-
year period, and a 35, 23, 10, and 4 percent chance that one, two,
three, or four whales, respectively, would be struck by each Action
Proponent over the 7-year period (with a 73 percent chance that at
least one whale would be struck by each Action Proponent over the
entire 7-year period). Based on this analysis, the Navy is requesting
authorization to take three large whales by serious injury or mortality
by vessel strike incidental to Navy training and testing activities,
and the Coast Guard is requesting authorization to take three large
whales by serious injury or mortality by vessel strike incidental to
Coast Guard training activities. NMFS concurs that take by serious
injury or mortality by vessel strike of up to three large whales by
each action proponent (six whales total) could occur over the 7-year
regulations and, based on the information provided earlier in this
section, NMFS concurs with the Action Proponents' assessment and
recognizes the potential for incidental take by vessel strike of large
whales only (i.e., no dolphins, small whales (not including large whale
calves), porpoises, or pinnipeds) over the course of the 7-year
regulations from military readiness activities.
While the Poisson distribution allows the Action Proponents and
NMFS to determine the likelihood of vessel strike of all large whales,
it does not indicate the likelihood of each strike occurring to a
particular species or stock. As described above, the Action Proponents
have not always been able to identify the species of large whale struck
during previous known vessel strikes. Therefore, the Action Proponents
requested authorization for take by serious injury or mortality by
vessel strike of any combination of the following stocks in the AFTT
Study Area, with no more than two takes total from any single stock:
humpback whale (Gulf of Maine stock), fin whale (Western North Atlantic
stock), sei whale (Nova Scotia stock), minke whale (Canadian East Coast
stock), blue whale (Western North Atlantic stock), and sperm whale
(North Atlantic stock).
After concurring that take of up to six large whales could occur
(three takes by each Action Proponent), and in consideration of the
Navy's request, NMFS considered which species could be among the six
large whales struck. NMFS conducted an analysis that considered several
factors: (1) The relative likelihood of striking one stock versus
another based on available strike data from all vessel types as denoted
in the SARs, (2) whether each Action Proponent has ever struck an
individual from a particular species or stock in the AFTT Study Area,
and if so, how many times, and (3) whether implementation of the
proposed mitigation measures (i.e., specific measures to reduce the
potential for vessel strike) would be expected to successfully prevent
vessel strikes of certain species or stocks (noting that, for all
stocks, activity-based mitigation would reduce the potential of vessel
strike).
To address number (1) above, NMFS compiled information from the
SARs (Hayes et al., 2024) on detected annual rates of large whale M/SI
from vessel strike (table 47). The annual rates of large whale serious
injury or mortality from vessel strike reported in the SARs help inform
the relative susceptibility of large whale species to vessel strike in
AFTT Study Area as recorded systematically over the five-year period
used for the SARs. We summed the annual rates of serious injury or
mortality from vessel strikes as reported in the SARs and then divided
each species' annual rate by this sum to get the percentage of total
annual strikes for each species/stock (table 47).
To inform the likelihood of a single action proponent striking a
particular species of large whale, we multiplied the percent of total
annual strikes for a given species in table 47 by the total percent
likelihood of a single action proponent striking at least one whale
(i.e., 73 percent, as described by the probability analysis above). We
also calculated the percent likelihood of a single action proponent
striking a particular species of large whale two or three times by
squaring or cubing, respectively, the value estimated for the
probability of striking a particular species of whale once (i.e., to
calculate the probability of an event occurring twice, multiply the
probability of the first event by the second). The results of these
calculations are reflected in the last two columns of table 47. We note
that these probabilities vary from year to year as the average annual
mortality changes depending on the specific range of time considered;
however, over the years and through updated data in the SARs, stocks
tend to consistently maintain a relatively higher or relatively lower
likelihood of being struck.

Table 47--Annual Rates of Mortality and Serious Injury From Vessel Collisions and Percent Likelihood of Each Action Proponent Striking a Large Whale
Species in the AFTT Study Area Over a 7-Year Period
--------------------------------------------------------------------------------------------------------------------------------------------------------
Annual rate of Percentage Percent Percent Percent
M/SI from of total likelihood likelihood likelihood
Species Stock vessel strike annual of 1 strike of 2 strikes of 3 strikes
a strikes over 7 years over 7 years over 7 years
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale.................................... Western North Atlantic.......... 0 0 0 0 0
Fin whale..................................... Western North Atlantic.......... 0.6 8.2 6 0.36 0.02
Humpback whale................................ Gulf of Maine................... 4.4 60.3 44 19.36 8.52
Minke whale................................... Canadian East Coast............. 0.8 11 8 0.64 0.05
North Atlantic right whale b.................. Western......................... 1.5 20.5 15 2.25 0.34
Rice's whale.................................. Northern Gulf of America........ 0 0 0 0 0
Sei whale..................................... Nova Scotia..................... 0 0 0 0 0
Sperm whale................................... North Atlantic.................. 0 0 0 0 0
Sperm whale................................... Northern Gulf of America........ 0 0 0 0 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
a Values are from the most recent stock assessment report (Hayes et al., 2024).
b While these percentages suggest that NARW has a quantitatively higher likelihood of vessel strike in comparison with other stocks, this proposed
rulemaking includes extensive mitigation measures for NARW that would minimize the risk of vessel strike such that vessel strike of this stock is not
anticipated to occur. Please see the discussion in this section and the Proposed Mitigation Measures section for additional detail.

[[Page 19983]]

The percent likelihood calculated (as described above) are then
considered in combination with the information indicating the known
species that the Navy or Coast Guard has struck in the AFTT Study Area
since 2000 (table 48). We note that for the lethal take of species
specifically denoted in table 48 below, most of those struck by the
Navy or Coast Guard remained unidentified. However, given the
information on known stocks struck, the analysis below remains
appropriate.

Table 48--Number of Known Vessel Strikes by Each Action Proponent in the
AFTT Study Area by Year
------------------------------------------------------------------------
Coast Guard
Year U.S. Navy strikes strikes (species/
(species/stock) stock)
------------------------------------------------------------------------
2000....................... 1 (unknown)............ 0.
2001....................... 4 (3 unknown, one
probable Puerto Rico/
U.S. Virgin Islands
stock sperm whale).
2004....................... 3 (unknown)............
2005....................... 2 (1 unknown, 1
probable sperm whale).
2009....................... ....................... 2 (NARW).
2011....................... 1 (unknown, probable
humpback whale).
2012....................... 2 (1 unknown, 1
probable humpback).
2021....................... 1 (dolphin)............
2024....................... ....................... 1 (unknown,
probable humpback
whale).
------------------------------------------------------------------------

Accordingly, stocks that have no record of ever having been struck
by any vessel are considered to have a zero percent likelihood of being
struck by the Navy in the 7-year period of the rule. While the Western
North Atlantic stock of blue whales, Northern Gulf of America stock of
Rice's whale, Nova Scotia stock of sei whales, and North Atlantic stock
of sperm whales have a reported annual rate of M/SI from vessel strike
of 0, each of these stocks have records of strikes prior to the period
reported in the SAR (Hayes et al. 2024). There is record of a vessel
strike in 1996 of a Western North Atlantic blue whale (Hayes et al.
2024), two records of vessel strike of Rice's whale (one in 2009 and
one in 2019), several records of vessel strikes in the 1990s and early
2000s of North Atlantic sperm whales, and a record of a probable sperm
whale (Northern Gulf of America stock) strike in 1990. For the Nova
Scotia stock of sei whale, several sei whale strandings during the time
period analyzed for the SAR (i.e., 2017-2021) had an undetermined cause
of death (Garron, 2022), and M/SI by vessel strike for sei whales along
the U.S. East Coast were a more common occurrence in previous SAR 5-
year periods (i.e., four from 2012-2016, three from 2007-2011, and two
from 2002-2006). Therefore, NMFS included each of these stocks for
further analysis, and considered the historical strikes, but lack of
recent strikes to inform the relative likelihood that the Navy or Coast
Guard would strike these stocks.
While Bryde's whales in the Atlantic are not a NMFS-managed stock,
the low number of estimated takes by harassment (11 takes by Level B
harassment) indicate very low overlap of this stock with the Action
Proponents' activities. As such, and given that there are no records of
either action proponent having struck Bryde's whale in the Atlantic in
the past, NMFS neither anticipates, nor proposes to authorize, serious
injury or mortality by vessel strike of Bryde's whale.
To address number (2) above, the percent likelihoods of a certain
number of strikes of each stock are then considered in combination with
the information indicating the species that the Action Proponents have
definitively struck in the AFTT Study Area since 2009. As noted above,
since 2009, the U.S. Navy and Coast Guard have each struck three whales
in the AFTT Study Area. The Navy struck one unidentified species in
June 2011, one unidentified species (thought to likely be a humpback)
in February 2012, and one unidentified species in October 2012. The
Coast Guard struck two whales (reported as NARW) in December 2009, and
one unidentified large whale (thought to likely be a humpback) in 2024.
Stocks that have never been struck by the Navy, have rarely been
struck by other vessels, and have a low percent likelihood based on the
historical vessel strike calculation are also considered to have a zero
percent likelihood to be struck by the Navy during the 7-year rule. As
noted in table 48, in 2001, the Navy struck an unidentified whale in
the Gulf of America, and given the stocks that occur there, that this
strike was of either a sperm whale or Rice's whale. Given the relative
abundance of these two stocks, NMFS expects that this strike was likely
of a sperm whale (Northern Gulf of America stock). Therefore, this step
in the analysis rules out take by vessel strike of blue whale and
Rice's whale. Even if the 2001 strike had been of a Rice's whale,
consideration of the proposed geographic mitigation for Rice's whale
(see Proposed Mitigation Measures section below) and the low stock
abundance further supports the conclusion that vessel strike of Rice's
whale is unlikely. This leaves the following stocks for further
analysis: fin whale (Western North Atlantic stock), humpback whale
(Gulf of Maine stock), minke whale (Canadian Eastern Coastal stock),
NARW (Western stock), sei whale (Nova Scotia stock), and sperm whale
(North Atlantic and Northern Gulf of America stocks).
Based on the information summarized in table 47, and the fact that
there is potential for up to six large whales to be struck over the 7-
year duration of this rulemaking, NMFS anticipates that each action
proponent could strike one of each of the following stocks (two total
per stock across both action proponents): fin whales (Western North
Atlantic stock), minke whales (Canadian Eastern Coastal stock), sei
whales (Nova Scotia stock), and sperm whales (North Atlantic stock).
NMFS also anticipates that the Navy may strike up to one sperm whale
(Northern Gulf of America stock) given the 2001 likely sperm whale
strike. Given the already lower likelihood of striking this stock given
the relatively lower vessel activity in the Gulf of America portion of
the AFTT Study Area, and the relatively lower Coast Guard vessel
traffic compared to Navy vessel traffic, NMFS neither anticipates, nor
proposes to authorize, a Coast Guard strike of this stock. NMFS
anticipates that each Action Proponent could strike up to two humpback
whales (Gulf of Maine stock) given the higher relative strike
likelihood indicated in table 47, and the Action

[[Page 19984]]

Proponents' conclusion that several previous Navy and Coast Guard
strikes of unidentified species were likely humpback whales.
Following the conclusion for the stocks above, NARW is the only
remaining stock. NARW are known to be particularly susceptible to
vessel strike, and vessel strike is one of the greatest threats to this
stock. NMFS' quantitative analysis (table 47) indicates a 15 percent
likelihood of one strike of NARW over the 7-year duration of this
proposed rulemaking. However, for the reasons described below, NMFS
does not anticipate vessel strike of NARW by either action proponent.
As stated previously, in 2009, the Coast Guard struck two whales
(reported as NARW). Since 2009, the Navy has had no known strikes of
NARW, and it has been implementing extensive mitigation measures to
avoid vessel strike of NARW. The lack of known strikes of NARWs
indicates that the mitigation used by the Navy since 2009 and included
here for the Action Proponents has likely been successful. Given that
the Navy will continue to implement this mitigation for NARW, and the
Coast Guard will begin implementing it also, (e.g., funding of and
communication with sightings systems, awareness of slow zones and
dynamic management areas for NARW) we neither anticipate nor propose to
authorize take by serious injury or mortality by vessel strike of NARW.
Please see the Proposed Mitigation Measures section of this proposed
rulemaking and section 11 of the application for additional detail.
In conclusion, although it is generally unlikely that any whales
will be struck in a year, based on the information and analysis above,
NMFS anticipates that no more than six takes of large whales by serious
injury or mortality could occur over the 7-year period of the rule,
with no more than three by each Action Proponent. Of those six whales
over the 7 years, no more than four may come from the Gulf of Maine
stock of humpback whale; no more than two may come from the Western
North Atlantic stock of fin whale, the Canadian East Coast stock of
minke whale, the Nova Scotia stock of sei whale, and the North Atlantic
stock of sperm whale; no more than one strike by the Navy may come from
the Northern Gulf of America stock of sperm whale. Accordingly, NMFS
has evaluated under the negligible impact standard the M/SI of 0.14,
0.29 or 0.57 whales annually from each of these species or stocks
(i.e., 1, 2 or 4 takes, respectively, divided by 7 years to get the
annual value), along with the expected incidental takes by harassment.

Summary of Requested Take From Military Readiness Activities

Table 49 and table 50 summarize the Action Proponents' take
proposed by harassment type and effect type, respectively.

Table 49--Total Annual and 7-Year Incidental Take Proposed by Stock During All Activities by Harassment Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Maximum
annual annual Maximum 7-Year total 7-Year total 7-Year total
Species Stock Level B Level A annual Level B Level A mortality
harassment harassment mortality harassment harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale................ Western..................... 414 2 0 2,682 8 0
Blue whale................................ Western North Atlantic...... 71 1 0 464 2 0
Bryde's whale............................. Primary..................... 11 0 0 70 0 0
Fin whale................................. Western North Atlantic...... 2,616 21 0.29 17,298 131 2
Humpback whale............................ Gulf of Maine............... 844 12 0.57 5,544 74 4
Minke whale............................... Canadian East Coast......... 4,643 56 0.29 31,006 377 2
Rice's whale.............................. Northern Gulf of America.... 303 3 0 2,047 6 0
Sei whale................................. Nova Scotia................. 747 7 0.29 4,981 44 2
Sperm whale............................... North Atlantic.............. 12,590 7 0.29 84,675 21 2
Sperm whale............................... Northern Gulf of America.... 275 0 0.29 1,653 0 1
Dwarf sperm whale......................... Northern Gulf of America.... 189 22 0 1,112 73 0
Pygmy sperm whale......................... Northern Gulf of America.... 175 22 0 1,017 65 0
Dwarf sperm whale......................... Western North Atlantic...... 6,326 180 0 42,547 1,184 0
Pygmy sperm whale......................... Western North Atlantic...... 6,294 176 0 42,302 1,157 0
Blainville's beaked whale................. Northern Gulf of America.... 126 0 0 812 0 0
Goose-beaked whale........................ Northern Gulf of America.... 460 0 0 2,962 0 0
Gervais' beaked whale..................... Northern Gulf of America.... 125 0 0 800 0 0
Blainville's beaked whale................. Western North Atlantic...... 25,705 1 0 172,587 1 0
Goose-beaked whale........................ Western North Atlantic...... 112,070 2 0 752,587 5 0
Gervais' beaked whale..................... Western North Atlantic...... 25,446 1 0 172,339 1 0
Northern bottlenose whale................. Western North Atlantic...... 1651 1 0 10,879 1 0
Sowerby's beaked whale.................... Western North Atlantic...... 25,622 1 0 173,546 1 0
True's beaked whale....................... Western North Atlantic...... 25,582 0 0 173,301 0 0
Atlantic spotted dolphin.................. Northern Gulf of America.... 12,804 20 0 83,827 123 0
Bottlenose dolphin........................ Gulf of America Eastern 80 0 0 455 0 0
Coastal.
Bottlenose dolphin........................ Gulf of America Northern 7,146 17 0 49,950 114 0
Coastal.
Bottlenose dolphin........................ Gulf of America, Oceanic.... 6,274 4 0 40,584 11 0
Bottlenose dolphin........................ Gulf of America Western 3,331 1 0 18,123 1 0
Coastal.
Bottlenose dolphin........................ Mississippi Sound, Lake 1,758 1 0 12,014 1 0
Borgne, and Bay Boudreau.
Bottlenose dolphin........................ Northern Gulf of America 71,331 29 0 481,391 165 0
Continental Shelf.
Bottlenose dolphin........................ Nueces and Corpus Christi 4 0 0 11 0 0
Bays.
Bottlenose dolphin........................ Sabine Lake................. 1 0 0 2 0 0
Bottlenose dolphin........................ St. Andrew Bay.............. 46 0 0 303 0 0
Bottlenose dolphin........................ St. Joseph Bay.............. 42 0 0 287 0 0
Bottlenose dolphin........................ Tampa Bay................... 350 0 0 1,050 0 0
Clymene dolphin........................... Northern Gulf of America.... 599 3 0 3,577 4 0
False killer whale........................ Northern Gulf of America.... 230 0 0 1,423 0 0
Fraser's dolphin.......................... Northern Gulf of America.... 241 0 0 1,487 0 0
Killer whale.............................. Northern Gulf of America.... 110 0 0 680 0 0
Melon-headed whale........................ Northern Gulf of America.... 771 1 0 4,806 1 0
Pygmy killer whale........................ Northern Gulf of America.... 285 0 0 1,773 0 0
Risso's dolphin........................... Northern Gulf of America.... 203 0 0 1,252 0 0

[[Page 19985]]

Rough-toothed dolphin..................... Northern Gulf of America.... 1,642 3 0 10,808 5 0
Short-finned pilot whale.................. Northern Gulf of America.... 1,021 3 0 6,183 13 0
Striped dolphin........................... Northern Gulf of America.... 2,376 7 0.29 15,414 15 2
Pantropical spotted dolphin............... Northern Gulf of America.... 6,316 9 0.71 39,959 28 5
Spinner dolphin........................... Northern Gulf of America.... 656 0 0 4,459 0 0
Atlantic white-sided dolphin.............. Western North Atlantic...... 10,901 9 0 71,669 43 0
Common dolphin............................ Western North Atlantic...... 269,405 161 0 1,820,556 1,015 0
Atlantic spotted dolphin.................. Western North Atlantic...... 120,798 87 0 796,804 577 0
Bottlenose dolphin........................ Indian River Lagoon 1,576 0 0 10,675 0 0
Estuarine System.
Bottlenose dolphin........................ Jacksonville Estuarine 360 0 0 2,477 0 0
System.
Bottlenose dolphin........................ Northern Georgia/Southern 2 0 0 6 0 0
South Carolina Estuarine
System.
Bottlenose dolphin........................ Northern North Carolina 10,532 6 0 72,036 37 0
Estuarine System.
Bottlenose dolphin........................ Southern Georgia Estuarine 123 1 0 711 1 0
System.
Bottlenose dolphin........................ Southern North Carolina 162 0 0 535 0 0
Estuarine System.
Tamanend's bottlenose dolphin............. Western North Atlantic 10,494 3 0 66,392 10 0
Central Florida Coastal.
Tamanend's bottlenose dolphin............. Western North Atlantic 21,385 5 0 142,945 13 0
Northern Florida Coastal.
Bottlenose dolphin........................ Western North Atlantic 73,720 60 0 507,610 375 0
Northern Migratory Coastal.
Bottlenose dolphin........................ Western North Atlantic 187,046 103 0.29 1,246,451 677 2
Offshore.
Tamanend's Bottlenose dolphin............. Western North Atlantic South 4,960 6 0.14 30,781 22 1
Carolina/Georgia Coastal.
Bottlenose dolphin........................ Western North Atlantic 10,180 9 0 64,883 52 0
Southern Migratory Coastal.
Clymene dolphin........................... Western North Atlantic...... 132,723 104 0.43 902,324 698 3
False killer whale........................ Western North Atlantic...... 572 1 0 3,872 1 0
Fraser's dolphin.......................... Western North Atlantic...... 2,905 3 0 19,435 14 0
Killer whale.............................. Western North Atlantic...... 180 1 0 1,195 1 0
Long-finned pilot whale................... Western North Atlantic...... 21,680 12 0 146,009 63 0
Melon-headed whale........................ Western North Atlantic...... 4,598 3 0 31,086 12 0
Pantropical spotted dolphin............... Western North Atlantic...... 13,068 5 0 89,174 25 0
Pygmy killer whale........................ Western North Atlantic...... 477 1 0 3,226 1 0
Risso's dolphin........................... Western North Atlantic...... 37,239 25 0 245,877 143 0
Rough-toothed dolphin..................... Western North Atlantic...... 4,753 6 0 31,562 25 0
Short-finned pilot whale.................. Western North Atlantic...... 33,035 15 0 222,007 91 0
Spinner dolphin........................... Western North Atlantic...... 5,356 2 0 36,513 10 0
Striped dolphin........................... Western North Atlantic...... 208,802 163 0 1,397,838 1,109 0
White-beaked dolphin...................... Western North Atlantic...... 16 0 0 103 0 0
Harbor porpoise........................... Gulf of Maine/Bay of Fundy.. 87,119 147 0 586,732 954 0
Gray seal................................. Western North Atlantic...... 15,724 24 0 105,585 151 0
Harbor seal............................... Western North Atlantic...... 22,094 32 0 148,486 204 0
Harp seal................................. Western North Atlantic...... 25,792 6 0 174,649 28 0
Hooded seal............................... Western North Atlantic...... 1,726 2 0 10,985 5 0
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 19986]]

Table 50--Total Annual and 7-Year Incidental Take Proposed by Stock During All Activities by Effect Type
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum
Maximum Maximum Maximum annual Maximum Maximum 7- Maximum 7- Maximum 7- Maximum 7-
Species Stock annual annual annual non- annual year Maximum 7- year AUD year non- year
behavioral TTS AUD INJ auditory mortality behavioral year TTS INJ auditory mortality
injury injury
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale............... Western.............................. 109 305 2 0 0 715 1,967 8 0 0
Blue whale............................... Western North Atlantic............... 12 59 1 0 0 73 391 2 0 0
Bryde's whale............................ Primary.............................. 2 9 0 0 0 7 63 0 0 0
Fin whale................................ Western North Atlantic............... 689 1,927 21 0 0.29 4,526 12,772 131 0 2
Humpback whale........................... Gulf of Maine........................ 212 632 12 0 0.57 1,404 4,140 74 0 4
Minke whale.............................. Canadian East Coast.................. 693 3,950 56 0 0.29 4,637 26,369 377 0 2
Rice's whale............................. Northern Gulf of America............. 88 215 3 0 0 593 1,454 6 0 0
Sei whale................................ Nova Scotia.......................... 125 622 7 0 0.29 822 4,159 44 0 2
Sperm whale.............................. North Atlantic....................... 8,878 3,712 6 1 0.29 59,196 25,479 20 1 2
Sperm whale.............................. Northern Gulf of America............. 248 27 0 0 0.29 1,507 146 0 0 1
Dwarf sperm whale........................ Northern Gulf of America............. 27 162 22 0 0 148 964 73 0 0
Pygmy sperm whale........................ Northern Gulf of America............. 28 147 22 0 0 163 854 65 0 0
Dwarf sperm whale........................ Western North Atlantic............... 1,308 5,018 180 0 0 8,686 33,861 1,184 0 0
Pygmy sperm whale........................ Western North Atlantic............... 1,341 4,953 176 0 0 8,907 33,395 1,157 0 0
Blainville's beaked whale................ Northern Gulf of America............. 126 0 0 0 0 812 0 0 0 0
Blainville's beaked whale................ Western North Atlantic............... 25,551 154 1 0 0 171,535 1,052 1 0 0
Goose-beaked whale....................... Northern Gulf of America............. 457 3 0 0 0 2,959 3 0 0 0
Goose-beaked whale....................... Western North Atlantic............... 111,457 613 2 0 0 748,360 4,227 5 0 0
Gervais' beaked whale.................... Northern Gulf of America............. 123 2 0 0 0 798 2 0 0 0
Gervais' beaked whale.................... Western North Atlantic............... 25,110 336 1 0 0 170,030 2,309 1 0 0
Northern bottlenose whale................ Western North Atlantic............... 1,642 9 1 0 0 10,822 57 1 0 0
Sowerby's beaked whale................... Western North Atlantic............... 25,257 365 1 0 0 171,033 2,513 1 0 0
True's beaked whale...................... Western North Atlantic............... 25,217 365 0 0 0 170,797 2,504 0 0 0
Atlantic spotted dolphin................. Northern Gulf of America............. 7,085 5,719 20 0 0 46,690 37,137 123 0 0
Bottlenose dolphin....................... Gulf of America Eastern Coastal...... 75 5 0 0 0 433 22 0 0 0
Bottlenose dolphin....................... Gulf of America Northern Coastal..... 6,524 622 17 0 0 45,608 4,342 114 0 0
Bottlenose dolphin....................... Gulf of America Oceanic.............. 4,764 1,510 4 0 0 30,923 9,661 11 0 0
Bottlenose dolphin....................... Gulf of America Western Coastal...... 1,773 1,558 1 0 0 9,846 8,277 1 0 0
Bottlenose dolphin....................... Mississippi Sound, Lake Borgne, and 1,715 43 1 0 0 11,776 238 1 0 0
Bay Boudreau.
Bottlenose dolphin....................... Northern Gulf of America Continental 46,801 24,530 27 2 0 321,346 160,045 163 2 0
Shelf.
Bottlenose dolphin....................... Nueces and Corpus Christi Bays....... 4 0 0 0 0 11 0 0 0 0
Bottlenose dolphin....................... Sabine Lake.......................... 1 0 0 0 0 2 0 0 0 0
Bottlenose dolphin....................... St. Andrew Bay....................... 45 1 0 0 0 302 1 0 0 0
Bottlenose dolphin....................... St. Joseph Bay....................... 42 0 0 0 0 287 0 0 0 0
Bottlenose dolphin....................... Tampa Bay............................ 163 187 0 0 0 490 560 0 0 0
Clymene dolphin.......................... Northern Gulf of America............. 390 209 2 1 0 2,308 1,269 3 1 0
False killer whale....................... Northern Gulf of America............. 168 62 0 0 0 1,036 387 0 0 0
Fraser's dolphin......................... Northern Gulf of America............. 168 73 0 0 0 1,031 456 0 0 0
Killer whale............................. Northern Gulf of America............. 84 26 0 0 0 521 159 0 0 0
Melon-headed whale....................... Northern Gulf of America............. 579 192 1 0 0 3,600 1,206 1 0 0
Pygmy killer whale....................... Northern Gulf of America............. 204 81 0 0 0 1,263 510 0 0 0
Risso's dolphin.......................... Northern Gulf of America............. 155 48 0 0 0 967 285 0 0 0
Rough-toothed dolphin.................... Northern Gulf of America............. 988 654 2 1 0 6,531 4,277 4 1 0
Short-finned pilot whale................. Northern Gulf of America............. 629 392 3 0 0 3,771 2,412 13 0 0
Striped dolphin.......................... Northern Gulf of America............. 1,728 648 5 2 0.29 11,266 4,148 10 5 2
Pantropical spotted dolphin.............. Northern Gulf of America............. 4,589 1,727 6 3 0.71 29,025 10,934 20 8 5
Spinner dolphin.......................... Northern Gulf of America............. 478 178 0 0 0 3,241 1,218 0 0 0
Atlantic white-sided dolphin............. Western North Atlantic............... 7,172 3,729 8 1 0 46,544 25,125 40 3 0
Common dolphin........................... Western North Atlantic............... 136,920 132,485 159 2 0 924,362 896,194 1,010 5 0
Atlantic spotted dolphin................. Western North Atlantic............... 51,840 68,958 85 2 0 343,981 452,823 571 6 0
Bottlenose dolphin....................... Indian River Lagoon Estuarine System. 1,438 138 0 0 0 9,717 958 0 0 0
Bottlenose dolphin....................... Jacksonville Estuarine System........ 269 91 0 0 0 1,855 622 0 0 0
Bottlenose dolphin....................... Northern Georgia/Southern South 2 0 0 0 0 6 0 0 0 0
Carolina Estuarine System.
Bottlenose dolphin....................... Northern North Carolina Estuarine 8,579 1,953 6 0 0 59,058 12,978 37 0 0
System.
Bottlenose dolphin....................... Southern Georgia Estuarine System.... 85 38 1 0 0 499 212 1 0 0
Bottlenose dolphin....................... Southern North Carolina Estuarine 82 80 0 0 0 256 279 0 0 0
System.

[[Page 19987]]

Tamanend's bottlenose dolphin............ Western North Atlantic Central 7,921 2,573 2 1 0 52,787 13,605 8 2 0
Florida Coastal.
Tamanend's bottlenose dolphin............ Western North Atlantic Northern 17,054 4,331 5 0 0 116,843 26,102 13 0 0
Florida Coastal.
Bottlenose dolphin....................... Western North Atlantic Northern 57,217 16,503 59 1 0 397,269 110,341 374 1 0
Migratory Coastal.
Bottlenose dolphin....................... Western North Atlantic Offshore...... 91,255 95,791 101 2 0.29 609,321 637,130 671 6 2
Tamanend's bottlenose dolphin............ Western North Atlantic South Carolina/ 1,426 3,534 6 0 0.14 8,970 21,811 22 0 1
Georgia Coastal.
Bottlenose dolphin....................... Western North Atlantic Southern 2,936 7,244 8 1 0 18,993 45,890 48 4 0
Migratory Coastal.
Clymene dolphin.......................... Western North Atlantic............... 60,223 72,500 102 2 0.43 403,316 499,008 694 4 3
False killer whale....................... Western North Atlantic............... 317 255 1 0 0 2,143 1,729 1 0 0
Fraser's dolphin......................... Western North Atlantic............... 1,362 1,543 3 0 0 9,135 10,300 14 0 0
Killer whale............................. Western North Atlantic............... 100 80 1 0 0 659 536 1 0 0
Long-finned pilot whale.................. Western North Atlantic............... 12,783 8,897 11 1 0 85,545 60,464 62 1 0
Melon-headed whale....................... Western North Atlantic............... 1,993 2,605 3 0 0 13,543 17,543 12 0 0
Pantropical spotted dolphin.............. Western North Atlantic............... 6,436 6,632 5 0 0 44,269 44,905 25 0 0
Pygmy killer whale....................... Western North Atlantic............... 216 261 1 0 0 1,471 1,755 1 0 0
Risso's dolphin.......................... Western North Atlantic............... 20,226 17,013 23 2 0 133,055 112,822 141 2 0
Rough-toothed dolphin.................... Western North Atlantic............... 1,874 2,879 6 0 0 12,519 19,043 25 0 0
Short-finned pilot whale................. Western North Atlantic............... 16,978 16,057 15 0 0 113,894 108,113 91 0 0
Spinner dolphin.......................... Western North Atlantic............... 2,607 2,749 2 0 0 17,788 18,725 10 0 0
Striped dolphin.......................... Western North Atlantic............... 107,596 101,206 161 2 0 708,184 689,654 1,103 6 0
White-beaked dolphin..................... Western North Atlantic............... 10 6 0 0 0 64 39 0 0 0
Harbor porpoise.......................... Gulf of Maine/Bay of Fundy........... 81,105 6,014 147 0 0 547,161 39,571 954 0 0
Gray seal................................ Western North Atlantic............... 9,811 5,913 24 0 0 66,633 38,952 151 0 0
Harbor seal.............................. Western North Atlantic............... 13,406 8,688 32 0 0 91,406 57,080 204 0 0
Harp seal................................ Western North Atlantic............... 16,636 9,156 6 0 0 111,591 63,058 28 0 0
Hooded seal.............................. Western North Atlantic............... 1,080 646 2 0 0 6,740 4,245 5 0 0
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: This includes effects from sonar and other transducers, air guns, pile driving, explosives (including small ship shock trials), and vessel strike.

[[Page 19988]]

Proposed Mitigation Measures

Under section 101(a)(5)(A) of the MMPA, NMFS must set forth the
permissible methods of taking pursuant to the activity, and other means
of effecting the least practicable adverse impact on the species or
stocks and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance, and on the
availability of the species or stocks for subsistence uses (``least
practicable adverse impact''). NMFS does not have a regulatory
definition for least practicable adverse impact. The 2004 NDAA amended
the MMPA as it relates to military readiness activities and the
incidental take authorization process such that a determination of
``least practicable adverse impact'' shall include consideration of
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity. For additional
discussion of NMFS' interpretation of the least practicable adverse
impact standard, see the Mitigation Measures section of the Gulf of
Alaska Study Area final rule (88 FR 604, January 4, 2023).

Implementation of Least Practicable Adverse Impact Standard

Here, we discuss how we determine whether a measure or set of
measures meets the ``least practicable adverse impact'' standard. Our
separate analysis of whether the take anticipated to result from the
Action Proponents' activities meets the ``negligible impact'' standard
appears in the Preliminary Analysis and Negligible Impact Determination
section below.
Our evaluation of potential mitigation measures includes
consideration of two primary factors: (1) The manner in which, and the
degree to which, implementation of the potential measure(s) is expected
to reduce adverse impacts to marine mammal species or stocks, their
habitat, or their availability for subsistence uses (where relevant).
This analysis considers such things as the nature of the potential
adverse impact (such as likelihood, scope, and range), the likelihood
that the measure will be effective if implemented, and the likelihood
of successful implementation; and (2) The practicability of the
measure(s) for applicant implementation. Practicability of
implementation may consider such things as cost, impact on activities,
and, in the case of a military readiness activity, specifically
considers personnel safety, practicality of implementation, and impact
on the effectiveness of the military readiness activity.
While the language of the least practicable adverse impact standard
calls for minimizing impacts to affected species or stocks, we
recognize that the reduction of impacts to those species or stocks
accrues through the application of mitigation measures that limit
impacts to individual animals. Accordingly, NMFS' analysis focuses on
measures that are designed to avoid or minimize impacts on individual
marine mammals that are more likely to increase the probability or
severity of population-level effects.
While direct evidence of impacts to species or stocks from a
specified activity is rarely available, and additional study is still
needed to understand how specific disturbance events affect the fitness
of individuals of certain species, there have been improvements in
understanding the process by which disturbance effects are translated
to the population. With recent scientific advancements (both marine
mammal energetic research and the development of energetic frameworks),
the relative likelihood or degree of impacts on species or stocks may
often be inferred given a detailed understanding of the activity, the
environment, and the affected species or stocks--and the best available
science has been used here. This same information is used in the
development of mitigation measures and helps us understand how
mitigation measures contribute to lessening effects (or the risk
thereof) to species or stocks. We also acknowledge that there is always
the potential that new information, or a new recommendation, could
become available in the future and necessitate reevaluation of
mitigation measures (which may be addressed through adaptive
management) to see if further reductions of population impacts are
possible and practicable.
In the evaluation of specific measures, the details of the
specified activity will necessarily inform each of the two primary
factors discussed above (expected reduction of impacts and
practicability), and are carefully considered to determine the types of
mitigation that are appropriate under the least practicable adverse
impact standard. Analysis of how a potential mitigation measure may
reduce adverse impacts on a marine mammal stock or species,
consideration of personnel safety, practicality of implementation, and
consideration of the impact on effectiveness of military readiness
activities are not issues that can be meaningfully evaluated through a
yes/no lens. The manner in which, and the degree to which,
implementation of a measure is expected to reduce impacts, as well as
its practicability in terms of these considerations, can vary widely.
For example, a time/area restriction could be of very high value for
decreasing population-level impacts (e.g., avoiding disturbance of
feeding females in an area of established biological importance) or it
could be of lower value (e.g., decreased disturbance in an area of high
productivity but of less biological importance). Regarding
practicability, a measure might involve restrictions in an area or time
that impede the Navy's ability to certify a strike group (higher impact
on mission effectiveness), or it could mean delaying a small in-port
training event by 30 minutes to avoid exposure of a marine mammal to
injurious levels of sound (lower impact). A responsible evaluation of
``least practicable adverse impact'' will consider the factors along
these realistic scales. Accordingly, the greater the likelihood that a
measure will contribute to reducing the probability or severity of
adverse impacts to the species or stock or its habitat, the greater the
weight that measure is given when considered in combination with
practicability to determine the appropriateness of the mitigation
measure, and vice versa. We discuss consideration of these factors in
greater detail below.
1. Reduction of adverse impacts to marine mammal species or stocks
and their habitat. The emphasis given to a measure's ability to reduce
the impacts on a species or stock considers the degree, likelihood, and
context of the anticipated reduction of impacts to individuals (and how
many individuals) as well as the status of the species or stock.
The ultimate impact on any individual from a disturbance event
(which informs the likelihood of adverse species- or stock-level
effects) is dependent on the circumstances and associated contextual
factors, such as duration of exposure to stressors. Though any proposed
mitigation needs to be evaluated in the context of the specific
activity and the species or stocks affected, measures with the
following types of effects have greater value in reducing the
likelihood or severity of adverse species- or stock-level impacts:
avoiding or minimizing injury or mortality; limiting interruption of
known feeding, breeding, mother/young, or resting behaviors; minimizing
the abandonment of important habitat (temporally and spatially);
minimizing the number of individuals subjected to these types of
disruptions; and limiting degradation of habitat. Mitigating these

[[Page 19989]]

types of effects is intended to reduce the likelihood that the activity
will result in energetic or other types of impacts that are more likely
to result in reduced reproductive success or survivorship. It is also
important to consider the degree of impacts that are expected in the
absence of mitigation in order to assess the added value of any
potential measures. Finally, because the least practicable adverse
impact standard gives NMFS discretion to weigh a variety of factors
when determining appropriate mitigation measures and because the focus
of the standard is on reducing impacts at the species or stock level,
the least practicable adverse impact standard does not compel
mitigation for every kind of take, or every individual taken, if that
mitigation is unlikely to meaningfully contribute to the reduction of
adverse impacts on the species or stock and its habitat, even when
practicable for implementation by the applicant.
The status of the species or stock is also relevant in evaluating
the appropriateness of potential mitigation measures in the context of
least practicable adverse impact. The following are examples of factors
that may (either alone, or in combination) result in greater emphasis
on the importance of a mitigation measure in reducing impacts on a
species or stock: the stock is known to be decreasing or status is
unknown, but believed to be declining; the known annual mortality (from
any source) is approaching or exceeding the potential biological
removal (PBR) level (as defined in MMPA section 3(20)); the affected
species or stock is a small, resident population; or the stock is
involved in a UME or has other known vulnerabilities, such as
recovering from an oil spill.
Habitat mitigation, particularly as it relates to rookeries, mating
grounds, and areas of similar significance, is also relevant to
achieving the standard and can include measures such as reducing
impacts of the activity on known prey utilized in the activity area or
reducing impacts on physical habitat. As with species- or stock-related
mitigation, the emphasis given to a measure's ability to reduce impacts
on a species or stock's habitat considers the degree, likelihood, and
context of the anticipated reduction of impacts to habitat. Because
habitat value is informed by marine mammal presence and use, in some
cases there may be overlap in measures for the species or stock and for
use of habitat. We consider available information indicating the
likelihood of any measure to accomplish its objective. If evidence
shows that a measure has not typically been effective nor successful,
then either that measure should be modified or the potential value of
the measure to reduce effects should be lowered.
2. Practicability. Factors considered may include cost, impact on
activities, and, in the case of a military readiness activity, will
include personnel safety, practicality of implementation, and impact on
the effectiveness of the military readiness activity (see MMPA section
101(a)(5)(A)(ii)).

Assessment of Mitigation Measures for the AFTT Study Area

NMFS has fully reviewed the specified activities and the mitigation
measures included in the application and the 2024 AFTT Draft
Supplemental EIS/OEIS to determine if the mitigation measures would
result in the least practicable adverse impact on marine mammals and
their habitat. NMFS worked with the Action Proponents in the
development of their initially proposed measures, which are informed by
years of implementation and monitoring. A complete discussion of the
Action Proponents' evaluation process used to develop, assess, and
select mitigation measures, which was informed by input from NMFS, can
be found in chapter 5 (Mitigation) of the 2024 AFTT Draft Supplemental
EIS/OEIS. The process described in chapter 5 (Mitigation) and appendix
A (Activity Descriptions) of the 2024 AFTT Draft Supplemental EIS/OEIS
robustly supported NMFS' independent evaluation of whether the
mitigation measures would meet the least practicable adverse impact
standard. The Action Proponents would be required to implement the
mitigation measures identified in this rule for the full 7 years to
avoid or reduce potential impacts from acoustic, explosive, and
physical disturbance and strike stressors.
As a general matter, where an applicant proposes measures that are
likely to reduce impacts to marine mammals, the fact that they are
included in the application indicates that the measures are
practicable, and it is not necessary for NMFS to conduct a detailed
analysis of the measures the applicant proposed (rather, they are
simply included). However, it is still necessary for NMFS to consider
whether there are additional practicable measures that would
meaningfully reduce the probability or severity of impacts that could
affect reproductive success or survivorship.
Overall the Action Proponents have agreed to mitigation measures
that would reduce the probability and/or severity of impacts expected
to result from acute exposure to acoustic sources or explosives, vessel
strike, and impacts to marine mammal habitat. Specifically, the Action
Proponents would use a combination of delayed starts, powerdowns, and
shutdowns to avoid mortality or serious injury, minimize the likelihood
or severity of AUD INJ or non-auditory injury, and reduce instances of
TTS or more severe behavioral disturbance caused by acoustic sources or
explosives. The Action Proponents would also implement multiple time/
area restrictions that would reduce take of marine mammals in areas or
at times where they are known to engage in important behaviors, such as
calving, where the disruption of those behaviors would have a higher
probability of resulting in impacts on reproduction or survival of
individuals that could lead to population-level impacts.
The Action Proponents assessed the practicability of the proposed
measures in the context of personnel safety, practicality of
implementation, and their impacts on the Action Proponents' ability to
meet their Congressionally mandated requirements and found that the
measures are supportable. As described in more detail below, NMFS has
independently evaluated the measures the Action Proponents proposed in
the manner described earlier in this section (i.e., in consideration of
their ability to reduce adverse impacts on marine mammal species and
their habitat and their practicability for implementation). We have
determined that the measures would significantly reduce impacts on the
affected marine mammal species and stocks and their habitat and,
further, be practicable for implementation by the Action Proponents. We
have preliminarily determined that the mitigation measures assure that
the Action Proponents' activities would have the least practicable
adverse impact on the species or stocks and their habitat.
The Action Proponents also evaluated numerous measures in the 2024
AFTT Draft Supplemental EIS/OEIS that were not included in the
application, and NMFS independently reviewed and preliminarily concurs
with the Action Proponents' analysis that their inclusion was not
appropriate under the least practicable adverse impact standard based
on our assessment. The Action Proponents considered these additional
potential mitigation measures in the context of the potential benefits
to marine mammals and whether they are practical or impractical.
Section 5.9 (Measures Considered but Eliminated) of chapter 5
(Mitigation) of

[[Page 19990]]

the 2024 AFTT Draft Supplemental EIS/OEIS, includes an analysis of an
array of different types of mitigation that have been recommended over
the years by non-governmental organizations or the public, through
scoping or public comment on environmental compliance documents. These
recommendations generally fall into three categories, discussed below:
reduction of activity, activity-based operational measures, and time/
area limitations.
As described in section 5.9 (Measures Considered but Eliminated) of
the 2024 AFTT Draft Supplemental EIS/OEIS, the Action Proponents
considered reducing the overall amount of training, reducing explosive
use, modifying sound sources, completely replacing live training with
computer simulation, and including time of day restrictions. Many of
these mitigation measures could potentially reduce the number of marine
mammals taken via direct reduction of the activities or amount of sound
energy put in the water. However, as described in chapter 5
(Mitigation) of the 2024 AFTT Draft Supplemental EIS/OEIS, the Action
Proponents need to train in the conditions in which they fight--and
these types of modifications fundamentally change the activity in a
manner that would not support the purpose and need for the training
(i.e., are entirely impracticable) and therefore are not considered
further. NMFS finds the Action Proponents' explanation of why adoption
of these recommendations would unacceptably undermine the purpose of
the training persuasive. After independent review, NMFS finds the
Action Proponents' judgment on the impacts of these potential
mitigation measures to personnel safety, practicality of
implementation, and the effectiveness of training persuasive, and for
these reasons, NMFS finds that these measures do not meet the least
practicable adverse impact standard because they are not practicable.
Also in chapter 5 (Mitigation) of the 2024 AFTT Draft Supplemental
EIS/OEIS, the Action Proponents evaluated additional potential
activity-based mitigation measures, including increased mitigation
zones, ramp-up measures, additional passive acoustic and visual
monitoring, and decreased vessel speeds. Some of these measures have
the potential to incrementally reduce take to some degree in certain
circumstances, though the degree to which this would occur is typically
low or uncertain. However, as described in the Action Proponents'
analysis, the measures would have significant direct negative effects
on mission effectiveness and are considered impracticable (see chapter
5 of the 2024 AFTT Draft Supplemental EIS/OEIS). NMFS independently
reviewed the Action Proponents' evaluation and concurs with this
assessment, which supports NMFS' preliminary findings that the
impracticability of this additional mitigation would greatly outweigh
any potential minor reduction in marine mammal impacts that might
result; therefore, these additional mitigation measures are not
warranted.
Last, chapter 5 (Mitigation) of the 2024 AFTT Draft Supplemental
EIS/OEIS also describes a comprehensive analysis of potential
geographic mitigation that includes consideration of both a biological
assessment of how the potential time/area limitation would benefit the
species and its habitat (e.g., is a key area of biological importance
or would result in avoidance or reduction of impacts) in the context of
the stressors of concern in the specific area and an operational
assessment of the practicability of implementation (e.g., including an
assessment of the specific importance of an area for training,
considering proximity to training ranges and emergency landing fields
and other issues). In some cases potential benefits to marine mammals
were non-existent, while in others the consequences on mission
effectiveness were too great.
NMFS has reviewed the Action Proponents' analysis in chapter 5
(Mitigation) and appendix A (Activity Descriptions) of the 2024 AFTT
Draft Supplemental EIS/OEIS, which consider the same factors that NMFS
considers to satisfy the least practicable adverse impact standard, and
concurs with the analysis and conclusions. Therefore, NMFS is not
proposing to include any of the measures that the Action Proponents
ruled out in the 2024 AFTT Draft Supplemental EIS/OEIS. Below are the
mitigation measures that NMFS has preliminarily determined would ensure
the least practicable adverse impact on all affected species and their
habitat, including the specific considerations for military readiness
activities. Table 51 describes the information designed to aid Lookouts
and other applicable personnel with their observation, environmental
compliance, and reporting responsibilities. The following sections
describe the mitigation measures that would be implemented in
association with the activities analyzed in this document. The
mitigation measures are organized into two categories: activity-based
mitigation and geographic mitigation areas.
Of note, according to the U.S. Navy, consistent with customary
international law, when a foreign military vessel participates in a
U.S. Navy exercise within the U.S. territorial sea (i.e., 0 to 12 nmi
(0 to 22.2 km) from shore), the U.S. Navy will request that the foreign
vessel follow the U.S. Navy's mitigation measures for that particular
event. When a foreign military vessel participates in a U.S. Navy
exercise beyond the U.S. territorial sea but within the U.S. Exclusive
Economic Zone, the U.S. Navy will encourage the foreign vessel to
follow the U.S. Navy's mitigation measures for that particular event
(Navy 2022a; Navy 2022b). In either scenario (i.e., both within and
beyond the territorial sea), U.S. Navy personnel will provide the
foreign vessels participating with a description of the mitigation
measures to follow.

Table 51--Environmental Awareness and Education
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: All training and testing activities, as
applicable.
------------------------------------------------------------------------
Requirements: Navy personnel (including civilian personnel) involved in
mitigation and training or testing activity reporting under the
specified activities must complete one or more modules of the U.S. Navy
Afloat Environmental Compliance Training Series, as identified in their
career path training plan. Modules include:
Introduction to Afloat Environmental Compliance Training
Series. The introductory module provides information on
environmental laws (e.g., ESA, MMPA) and the corresponding
responsibilities that are relevant to military readiness
activities. The material explains why environmental compliance is
important in supporting the Action Proponents' commitment to
environmental stewardship.
Marine Species Awareness Training. All bridge watch
personnel, Commanding Officers, Executive Officers, maritime patrol
aircraft aircrews, anti-submarine warfare and mine warfare rotary-
wing aircrews, Lookouts, and equivalent civilian personnel must
successfully complete the Marine Species Awareness Training prior
to standing watch or serving as a Lookout. The Marine Species
Awareness Training provides information on sighting cues, visual
observation tools and techniques, and sighting notification
procedures. Navy biologists developed Marine Species Awareness
Training to improve the effectiveness of visual observations for
biological resources, focusing on marine mammals and sea turtles,
and including floating vegetation, jellyfish aggregations, and
flocks of seabirds.

[[Page 19991]]

Protective Measures Assessment Protocol. This module
provides the necessary instruction for accessing mitigation
requirements during the event planning phase using the Protective
Measures Assessment Protocol (PMAP) software tool.
Sonar Positional Reporting System and Marine Mammal
Incident Reporting. This module provides instruction on the
procedures and activity reporting requirements for the Sonar
Positional Reporting System and marine mammal incident reporting.
------------------------------------------------------------------------

Activity-Based Mitigation

Activity-based mitigation is mitigation that the Action Proponents
would implement whenever and wherever an applicable military readiness
activity takes place within the AFTT Study Area. Previously referred to
as ``Procedural Mitigation,'' the primary objective of activity-based
mitigation is to reduce overlap of marine mammals with stressors that
have the potential to cause injury or mortality in real time. Activity-
based mitigations are fundamentally consistent across stressor
activity, although specific variations account for differences in
platform configuration, event characteristics, and stressor types. The
Action Proponents customize mitigation for each applicable activity
category or stressor. Activity-based mitigation generally involves: (1)
The use of one or more trained Lookouts to diligently observe for
marine mammals and other specific biological resources (e.g., indicator
species like floating vegetation, jelly aggregations, large schools of
fish, and flocks of seabirds) within a mitigation zone, (2)
requirements for Lookouts to immediately communicate sightings of
marine mammals and other specific biological resources to the
appropriate watch station for information dissemination, and (3)
requirements for the watch station to implement mitigation (e.g., halt
an activity) until certain recommencement conditions have been met. The
remainder of the mitigation measures are activity-based mitigation
measures (table 52 through table 70) organized by stressor type and
activity category and include acoustic stressors (i.e., active sonar,
air guns, pile driving, weapons firing noise), explosive stressors
(i.e., sonobuoys, torpedoes, medium-caliber and large-caliber
projectiles, missiles and rockets, bombs, SINKEX, mine counter-measure
and neutralization activities, mine neutralization involving Navy
divers, line charge testing, ship shock trials), and physical
disturbance and strike stressors (i.e., vessel movement, towed in-water
devices, small-, medium-, and large-caliber non-explosive practice
munitions, non-explosive missiles and rockets, non-explosive bombs,
mine shapes).
The Action Proponents must implement the proposed mitigation
measures described in table 52 through table 70, as appropriate, in
response to an applicable sighting within, or entering into, the
relevant mitigation zone for acoustic stressors, explosives, and non-
explosive munitions. Each table describes the activities that the
requirements apply to, the required mitigation zones in which the
action proponents must take a mitigation action, the required number of
Lookouts and observation platform, the required mitigation actions that
the action proponents must take before, during, and/or after an
activity, and a required wait period prior to commencing or
recommencing an activity after a delay, power down, or shutdown of an
activity.
The Action Proponents proposed wait periods because events cannot
be delayed or ceased indefinitely for the purpose of mitigation due to
impacts on safety, sustainability, and the ability to meet mission
requirements. Wait periods are designed to allow animals the maximum
amount of time practical to resurface (i.e., become available to be
observed) before activities resume. The action proponents factored in
an assumption that mitigation may need to be implemented more than once
when developing wait period durations. Wait periods are 10 minutes, 15
minutes, or 30 minutes depending on the fuel constraints of the
platform and feasibility of implementation. NMFS concurs with these
proposed wait periods.
If an applicable species (identified in relevant mitigation table)
is observed within a required mitigation zone prior to the initial
start of the activity, the Action Proponents must: (1) relocate the
event to a location where applicable species are not observed, or (2)
delay the initial start of the event (or stressor use) until one of the
``Mitigation Zone All-Clear Conditions'' (defined below) has been met.
If an applicable stressor is observed within a required mitigation zone
during the event (i.e., during use of the indicated source) the Action
Proponents must take the action described in the ``Mitigation Zones''
section of the table until one of the Mitigation Zone All-Clear
Conditions has been met.
For all activities, an activity may not commence or recommence
until one of the following ``Mitigation Zone All-Clear Conditions''
have been met: (1) a Lookout observes the applicable species exiting
the mitigation zone, (2) a Lookout determines the applicable species
has exited the mitigation zone based on its observed course and speed
relative to the mitigation zone, (3) a Lookout affirms the mitigation
zone has been clear from additional sightings for a designated ``wait
period,'' or (4) for mobile events, the stressor has transited a
distance equal to double the mitigation zone size beyond the location
of the last sighting.
Activity-Based Mitigation for Active Acoustic Stressors
Mitigation measures for acoustic stressors are provided below and
include active acoustic sources (table 52), pile driving and extraction
(table 53), and weapons firing noise (table 54). Activity-based
mitigation for acoustic stressors does not apply to:
(i) sources not operated under positive control (i.e., sources not
actively controlled by a crewmember, e.g., unmanned platforms
performing predetermined operations);
(ii) sources used for safety of navigation;
(iii) sources used or deployed by aircraft operating at high
altitudes;
(iv) sources used, deployed, or towed by unmanned platforms except
when escort vessels are already participating in the event and have
positive control over the source;
(v) sources used by submerged submarines;
(vi) de minimis sources;
(vii) long-duration sources, including those used for acoustic and
oceanographic research; and
(viii) vessel-based, unmanned vehicle-based, or towed in-water
sources when marine mammals (e.g., dolphins) are determined to be
intentionally swimming at the bow or alongside or directly behind the
vessel, vehicle, or device (e.g., to bow-ride or wake-ride).

[[Page 19992]]

Table 52--Mitigation for Active Acoustic Sources
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: Active acoustic sources with power down and shut
down capabilities:
Low-frequency active sonar >=200 dB.
Mid-frequency active sonar sources that are hull mounted on
a surface ship (including surfaced submarines).
Broadband and other active acoustic sources >200 dB.
------------------------------------------------------------------------
Mitigation Zones:
[cir] 1,000 yd (914.4 m) from active acoustic sources (power
down of 6 dB total).
[cir] 500 yd (457.2 m) from active acoustic sources (power down
of 10 dB total).
[cir] 200 yd (182.9 m) from active acoustic sources (shut down).
Mitigation Requirements:
[cir] One Lookout in/on one of the following:
[ssquf] Aircraft.
[ssquf] Pierside, moored, or anchored vessel.
[ssquf] Underway vessel with space/crew restrictions
(including small boats).
[ssquf] Underway vessel already participating in the event
that is escorting (and has positive control over sources
used, deployed, or towed by) an unmanned platform.
[cir] Two Lookouts on an underway vessel without space/crew
restrictions.
[cir] Lookouts would use information from passive acoustic
detections to inform visual observations when passive acoustic
devices are already being used in the event.
Mitigation Requirement Timing:
[cir] Action Proponent personnel must observe the applicable
mitigation zone for marine mammals and floating vegetation
immediately prior to the initial start of using active acoustic
sources (e.g., while maneuvering on station).
[cir] Action Proponent personnel must observe the applicable
mitigation zone for marine mammals during use of active
acoustic sources.
Wait Period:
[cir] 10 or 30 minutes (depending on fuel constraints of the
platform).
------------------------------------------------------------------------
Stressor or Activity: Active acoustic sources with shut down (but not
power down) capabilities:
Low-frequency active sonar <200 dB.
Mid-frequency active sonar sources that are not hull
mounted on a surface ship (e.g., dipping sonar, towed arrays).
High-frequency active sonar.
Air guns.
Broadband and other active acoustic sources <200 dB.
------------------------------------------------------------------------
Mitigation Zone:
200 yd (182.9 m) from active acoustic sources (shut
down).
Mitigation Requirements:
One Lookout in/on one of the following:
Aircraft.
Pierside, moored, or anchored vessel.
Underway vessel with space/crew restrictions
(including small boats).
Underway vessel already participating in the event
that is escorting (and has positive control over sources
used, deployed, or towed by) an unmanned platform.
Two Lookouts on an underway vessel without space/crew
restrictions.
Lookouts would use information from passive acoustic
detections to inform visual observations when passive acoustic
devices are already being used in the event.
Mitigation Requirement Timing:
Action Proponent personnel must observe the mitigation
zone for marine mammals and floating vegetation immediately
prior to the initial start of using active acoustic sources
(e.g., while maneuvering on station).
Action Proponent personnel must observe the mitigation
zone for marine mammals during use of active acoustic sources.
Wait Period:
10 or 30 minutes (depending on fuel constraints of the
platform).
------------------------------------------------------------------------

Table 53--Mitigation for Pile Driving and Extraction
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: Vibratory and impact pile driving and extraction.
------------------------------------------------------------------------
Mitigation Zone:
100 yd (91.4 m) from piles being driven or extracted
(cease pile driving or extraction).
Mitigation Requirements
One Lookout on one of the following:
Shore.
Pier.
Small boat.
Mitigation Requirement Timing:
Action Proponent personnel must observe the mitigation
zone for marine mammals and floating vegetation for 15 minutes
prior to the initial start of pile driving or pile extraction.
Action Proponent personnel must observe the mitigation
zone for marine mammals during pile driving or extraction.
Wait Period:
15 minutes.
------------------------------------------------------------------------

[[Page 19993]]

Table 54--Mitigation for Weapons Firing Noise
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: Explosive and non-explosive large-caliber gunnery
firing noise (surface-to-surface and surface-to-air).
------------------------------------------------------------------------
Mitigation Zone:
30 degrees on either side of the firing line out to 70
yd (64 m) from the gun muzzle (cease fire).
Mitigation Requirements:
One Lookout on a vessel.
Mitigation Requirement Timing:
Action Proponent personnel must observe the mitigation
zone for marine mammals and floating vegetation immediately
prior to the initial start of large-caliber gun firing (e.g.,
during target deployment).
Action Proponent personnel must observe the mitigation
zone for marine mammals during large-caliber gun firing.
Wait Period:
30 minutes.
------------------------------------------------------------------------

Activity-Based Mitigation for Explosive Stressors
Mitigation measures for explosive stressors are provided below and
include explosive bombs (table 55), explosive gunnery (table 56),
explosive line charges (table 57), explosive mine countermeasure and
neutralization without divers (table 58), explosive mine neutralization
with divers (table 59), explosive missiles and rockets (table 60),
explosive sonobuoys and research-based sub-surface explosives (table
61), explosive torpedoes (table 62), ship shock trials (table 63), and
SINKEX (table 64). After the event, the Action Proponents must observe
the area for marine mammals. Post-event observations are intended to
aid incident reporting requirements for marine mammals. Practicality
and the duration of post-event observations will be determined on site
by fuel restrictions and mission-essential follow-on commitments. For
example, it is more challenging to remain on-site for extended periods
of time for some activities due to factors such as range from the
target or altitude of an aircraft. Activity-based mitigation for
explosive stressors does not apply to explosives:
(i) deployed by aircraft operating at high altitudes;
(ii) deployed by submerged submarines, except for explosive
torpedoes;
(iii) deployed against aerial targets;
(iv) during vessel-launched missile or rocket events;
(v) used at or below the de minimis threshold; and
(vi) deployed by unmanned platforms except when escort vessels are
already participating in the event and have positive control over the
explosive.

Table 55--Mitigation for Explosive Bombs
------------------------------------------------------------------------

Table 56--Mitigation for Explosive Gunnery
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: Air-to-surface medium-caliber, surface-to-surface
medium-caliber, surface-to-surface large-caliber.
------------------------------------------------------------------------
Mitigation Zones:
[cir] Air-to-surface medium-caliber:
[ssquf] 200 yd (182.9 m) from the intended impact location
(cease fire).
[cir] Surface-to-surface medium-caliber:
[ssquf] 600 yd (548.6 m) from the intended impact location
(cease fire).
[cir] Surface-to-surface large-caliber:
[ssquf] 1,000 yd (914.4 m) from the intended impact location
(cease fire).
Mitigation Requirements:
[cir] One Lookout on a vessel or in an aircraft.
Mitigation Requirement Timing:
[cir] Action Proponent personnel must observe the applicable
mitigation zone for marine mammals and floating vegetation
immediately prior to the initial start of gun firing (e.g.,
while maneuvering on station).
[cir] Action Proponent personnel must observe the applicable
mitigation zone for marine mammals during gunnery fire.
[cir] After the event, when practical, Action Proponent
personnel must observe the detonation vicinity for injured or
dead marine mammals. If any injured or dead marine mammals are
observed, Action Proponent personnel must follow established
incident reporting procedures.
Wait Period:

[[Page 19994]]

[cir] 10 or 30 minutes (depending on fuel constraints of the
platform).
------------------------------------------------------------------------

Table 57--Mitigation for Explosive Line Charges
------------------------------------------------------------------------

Table 58--Mitigation for Explosive Mine Countermeasure and
Neutralization (No Divers)
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: 0.1-5 lb (0.05-2.3 kg) NEW, >5 lb (2.3 kg) NEW.
------------------------------------------------------------------------
Mitigation Zones:
[cir] 0.1-5 lb (0.05-2.3 kg) NEW:
[ssquf] 600 yd (548.6 m) from the detonation site (cease
fire).
[cir] >5 lb (2.3 kg) NEW:
[ssquf] 2,100 yd (1,920.2 m) from the detonation site (cease
fire).
Mitigation Requirements:
[cir] 0.1-5 lb (0.05-2.3 kg) NEW:
[ssquf] One Lookout on a vessel or in an aircraft.
[cir] >5 lb (2.3 kg) NEW:
[ssquf] Two Lookouts: one on a small boat and one in an
aircraft.
Mitigation Requirement Timing:
[cir] Action Proponent personnel must observe the applicable
mitigation zone for marine mammals and floating vegetation
immediately prior to the initial start of detonations (e.g.,
while maneuvering on station; typically, 10 or 30 minutes
depending on fuel constraints).
[cir] Action Proponent personnel must observe the applicable
mitigation zone for marine mammals during detonations or fuse
initiation.
[cir] After the event, when practical, Action Proponent
personnel must observe the detonation vicinity for 10 or 30
minutes (depending on fuel constraints) for injured or dead
marine mammals. If any injured or dead marine mammals are
observed, Action Proponent personnel must follow established
incident reporting procedures.
Wait Period:
[cir] 10 or 30 minutes (depending on fuel constraints of the
platform).
------------------------------------------------------------------------

Table 59--Mitigation for Explosive Mine Neutralization (With Divers)
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: 0.1-20 lb (0.05-9.1 kg) NEW (positive control),
0.1-20 lb (0.05-9.1 kg) NEW (time-delay), >20-60 lb (9.1-27.2 kg) NEW
(positive control).
------------------------------------------------------------------------
Mitigation Zones:
[cir] 0.1-20 lb (0.05-9.1 kg) NEW (positive control):
[ssquf] 500 yd (457.2 m) from the detonation site (cease
fire).
[cir] 0.1-20 lb (0.05-9.1 kg) NEW (time-delay), >20-60 lb (9.1-
27.2 kg) NEW (positive control):
[ssquf] 1,000 yd (914.4 m) from the detonation site (cease
fire).
Mitigation Requirements:
[cir] 0.1-20 lb (0.05-9.1 kg) NEW (positive control):
[ssquf] Two Lookouts in two small boats (one Lookout per
boat) or one small boat and one rotary-wing aircraft (with
one Lookout each).
[cir] 0.1-20 lb (0.05-9.1 kg) NEW (time-delay), >20-60 lb (9.1-
27.2 kg) NEW (positive control):
[ssquf] Four Lookouts in two small boats (two Lookouts per
boat), and one additional Lookout in an aircraft if used in
the event.
Mitigation Requirement Timing:
[cir] Time-delay devices must be set not to exceed 10 minutes.
[cir] Action Proponent personnel must observe the applicable
mitigation zone for marine mammals and floating vegetation
immediately prior to the initial start of detonations or fuse
initiation for positive control events (e.g., while maneuvering
on station) or for 30 minutes prior for time-delay events.
[cir] Action Proponent personnel must observe the applicable
mitigation zone for marine mammals during detonations or fuse
initiation.
[cir] When practical based on mission, safety, and environmental
conditions:
[ssquf] Boats must observe from the mitigation zone radius
mid-point.
[ssquf] When two boats are used, boats must observe from
opposite sides of the mine location.
[ssquf] Platforms must travel a circular pattern around the
mine location.
[ssquf] Boats must have one Lookout observe inward toward
the mine location and one Lookout observe outward toward
the mitigation zone perimeter.

[[Page 19995]]

[ssquf] Divers must be part of the Lookout Team.
[cir] After the event, when practical, Action Proponent
personnel must observe the detonation vicinity for 30 minutes
for injured or dead marine mammals. If any injured or dead
marine mammals are observed, Action Proponent personnel must
follow established incident reporting procedures.
Wait Period:
[cir] 10 or 30 minutes (depending on fuel constraints of the
platform).
------------------------------------------------------------------------

Table 60--Mitigation for Explosive Missiles and Rockets
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: 0.6-20 lb (0.3-9.1 kg) NEW (air-to-surface), >20-
500 lb (9.1-226.8 kg) NEW (air-to-surface).
------------------------------------------------------------------------
Mitigation Zones:
[cir] 0.6-20 lb (0.3-9.1 kg) NEW (air-to-surface):
[ssquf] 900 yd (823 m) from the intended impact location
(cease fire).
[cir] >20-500 lb (9.1-226.8 kg) NEW (air-to-surface):
[ssquf] 2,000 yd (1,828.8 m) from the intended impact
location (cease fire).
Mitigation Requirements:
[cir] One Lookout in an aircraft.
Mitigation Requirement Timing:
[cir] Action Proponent personnel must observe the applicable
mitigation zone for marine mammals and floating vegetation
immediately prior to the initial start of missile or rocket
delivery (e.g., during a fly-over of the mitigation zone).
[cir] Action Proponent personnel must observe the applicable
mitigation zone for marine mammals during missile or rocket
delivery.
[cir] After the event, when practical, Action Proponent
personnel must observe the detonation vicinity for injured or
dead marine mammals. If any injured or dead marine mammals are
observed, Action Proponent personnel must follow established
incident reporting procedures.
Wait Period:
[cir] 10 or 30 minutes (depending on fuel constraints of the
platform).
------------------------------------------------------------------------

Table 61--Mitigation for Explosive Sonobuoys and Research-Based Sub-
Surface Explosives
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: Any NEW of sonobuoys, 0.1-5 lb (0.05-2.3 kg) NEW
for other types of sub-surface explosives used in research
applications.
------------------------------------------------------------------------
Mitigation Zones:
[cir] 600 yd (548.6 m) from the device or detonation sites
(cease fire).
Mitigation Requirements:
[cir] One Lookout on a small boat or in an aircraft.
[cir] Conduct passive acoustic monitoring for marine mammals;
use information from detections to assist visual observations.
Mitigation Requirement Timing:
[cir] Action Proponent personnel must observe the mitigation
zone for marine mammals and floating vegetation immediately
prior to the initial start of detonations (e.g., during
sonobuoy deployment, which typically lasts 20-30 minutes).
[cir] Action Proponent personnel must observe the mitigation
zone for marine mammals during detonations.
[cir] After the event, when practical, Action Proponent
personnel must observe the detonation vicinity for injured or
dead marine mammals. If any injured or dead marine mammals are
observed, Action Proponent personnel must follow established
incident reporting procedures.
Wait Period:
[cir] 10 or 30 minutes (depending on fuel constraints of the
platform).
------------------------------------------------------------------------

Table 62--Mitigation for Explosive Torpedoes
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: Any NEW.
------------------------------------------------------------------------
Mitigation Zone:
[cir] 2,100 yd (1,920.2 m) from the intended impact location
(cease fire).
Mitigation Requirements:
[cir] One Lookout in an aircraft.
[cir] Conduct passive acoustic monitoring for marine mammals;
use information from detections to assist visual observations.
Mitigation Requirement Timing:
[cir] Action Proponent personnel must observe the mitigation
zone for marine mammals, floating vegetation, and jellyfish
aggregations immediately prior to the initial start of
detonations (e.g., during target deployment).
[cir] Action Proponent personnel must observe the mitigation
zone for marine mammals and jellyfish aggregations during
torpedo launches.
[cir] After the event, when practical, Action Proponent
personnel must observe the detonation vicinity for injured or
dead marine mammals. If any injured or dead marine mammals are
observed, Action Proponent personnel must follow established
incident reporting procedures.
Wait Period:
[cir] 10 or 30 minutes (depending on fuel constraints of the
platform).
------------------------------------------------------------------------

[[Page 19996]]

Table 63--Mitigation for Ship Shock Trials
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: Any NEW.
------------------------------------------------------------------------
Mitigation Zone:
[cir] 3.5 nmi (6.5 km) from the target ship hull (cease fire).
Mitigation Requirements:
[cir] On the day of the event, 10 observers (Lookouts and third-
party observers combined), spread between aircraft or multiple
vessels as specified in the event-specific mitigation plan.
Mitigation Requirement Timing:
[cir] Action Proponent personnel must develop a detailed, event-
specific monitoring and mitigation plan in the year prior to
the event and provide it to NMFS for review.
[cir] Beginning at first light on days of detonation, until the
moment of detonation (as allowed by safety measures) Action
Proponent personnel must observe the mitigation zone for marine
mammals, floating vegetation, jellyfish aggregations, large
schools of fish, and flocks of seabirds.
[cir] If any dead or injured marine mammals are observed after
an individual detonation, Action Proponent personnel must
follow established incident reporting procedures and halt any
remaining detonations until Action Proponent personnel or third-
party observers can consult with NMFS and review or adapt the
event-specific mitigation plan, if necessary.
[cir] During the 2 days following the event (minimum) and up to
7 days following the event (maximum), and as specified in the
event-specific mitigation plan, Action Proponent personnel must
observe the detonation vicinity for injured or dead marine
mammals.
Wait Period:
[cir] 30 minutes.
------------------------------------------------------------------------

Table 64--Mitigation for Sinking Exercises (SINKEX)
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: Any NEW.
------------------------------------------------------------------------
Mitigation Zone:
[cir] 2.5 nmi (4.6 km) from the target ship hull (cease fire).
Mitigation Requirements:
[cir] Two Lookouts: one on a vessel and one in an aircraft.
[cir] Conduct passive acoustic monitoring for marine mammals;
use information from detections to assist visual observations.
Mitigation Requirement Timing:
[cir] During aerial observations for 90 minutes prior to the
initial start of weapon firing, Action Proponent personnel must
observe the mitigation zone for marine mammals, floating
vegetation, and jellyfish aggregations.
[cir] From the vessel during weapon firing, and from the
aircraft and vessel immediately after planned or unplanned
breaks in weapon firing of more than 2 hours, Action Proponent
personnel must observe the mitigation zone for marine mammals.
[cir] Action Proponent personnel must observe the detonation
vicinity for injured or dead marine mammals for 2 hours after
sinking the vessel or until sunset, whichever comes first. If
any injured or dead marine mammals are observed, Action
Proponent personnel must follow established incident reporting
procedures.
Wait Period:
[cir] 30 minutes.
------------------------------------------------------------------------

Activity-Based Mitigation for Non-Explosive Ordnance
Mitigation measures for non-explosive ordnance are provided below
and include non-explosive aerial-deployed mines and bombs (table 65),
non-explosive gunnery (table 66), and non-explosive missiles and
rockets (table 67). Explosive aerial-deployed mines do not detonate
upon contact with the water surface and are therefore considered non-
explosive when mitigating the potential for a mine shape to strike a
marine mammal at the water surface. Activity-based mitigation for non-
explosive ordnance does not apply to non-explosive ordnance deployed:
(i) by aircraft operating at high altitudes;
(ii) against aerial targets;
(iii) during vessel-launched missile or rocket events; and
(iv) by unmanned platforms except when escort vessels are already
participating in the event and have positive control over ordnance
deployment.

Table 65--Mitigation for Non-Explosive Aerial-Deployed Mines and Bombs
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: Non-explosive aerial-deployed mines and non-
explosive bombs.
------------------------------------------------------------------------
Mitigation Zone:
[cir] 1,000 yd (914.4 m) from the intended target (cease fire).
Mitigation Requirements:
[cir] One Lookout in an aircraft.
Mitigation Requirement Timing:
[cir] Action Proponent personnel must observe the mitigation
zone for marine mammals and floating vegetation immediately
prior to the initial start of mine or bomb delivery (e.g., when
arriving on station).
[cir] Action Proponent personnel must observe the mitigation
zone for marine mammals during mine or bomb delivery.
Wait Period:
[cir] 10 minutes.
------------------------------------------------------------------------

[[Page 19997]]

Table 66--Mitigation for Non-Explosive Gunnery
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: Non-explosive surface-to-surface large-caliber
ordnance, non-explosive surface-to-surface and air-to-surface medium-
caliber ordnance, non-explosive surface-to-surface and air-to-surface
small-caliber ordnance.
------------------------------------------------------------------------
Mitigation Zone:
[cir] 200 yd (182.9 m) from the intended impact location (cease
fire).
Mitigation Requirements:
[cir] One Lookout on a vessel or in an aircraft.
Mitigation Requirement Timing:
[cir] Action Proponent personnel must observe the mitigation
zone for marine mammals and floating vegetation immediately
prior to the start of gun firing (e.g., while maneuvering on
station).
[cir] Action Proponent personnel must observe the mitigation
zone for marine mammals during gunnery firing.
Wait Period:
[cir] 10 or 30 minutes (depending on fuel constraints of the
platform).
------------------------------------------------------------------------

Table 67--Mitigation for Non-Explosive Missiles and Rockets
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: Non-explosives (air-to-surface).
------------------------------------------------------------------------
Mitigation Zone:
[cir] 900 yd (823 m) from the intended impact location (cease
fire).
Mitigation Requirements:
[cir] One Lookout in an aircraft.
Mitigation Requirement Timing:
[cir] Action Proponent personnel must observe the mitigation
zone for marine mammals and floating vegetation immediately
prior to the start of missile or rocket delivery (e.g., during
a fly-over of the mitigation zone).
[cir] Action Proponent personnel must observe the mitigation
zone for marine mammals during missile or rocket delivery.
Wait Period:
[cir] 10 or 30 minutes (depending on fuel constraints of the
platform).
------------------------------------------------------------------------

Activity-Based Mitigation for Physical Disturbance and Strike Stressors
Mitigation measures for physical disturbance and strike stressors
are provided below and include manned surface vessels (table 68),
unmanned vehicles (table 69), and towed in-water devices (table 70).

Table 68--Mitigation for Manned Surface Vessels
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: Manned surface vessels, including surfaced
submarines.
------------------------------------------------------------------------
Mitigation Zones:
[cir] Underway manned surface vessels must maneuver themselves
(which may include reducing speed) to maintain the following
distances as mission and circumstances allow:
[ssquf] 500 yd (457.2 m) from whales.
[ssquf] 200 yd (182.9 m) from other marine mammals.
Mitigation Requirements:
[cir] One or more Lookouts on manned underway surface vessels in
accordance with the most recent navigation safety instruction.
Mitigation Requirement Timing:
[cir] Action Proponent personnel must observe the mitigation
zone for marine mammals immediately prior to manned surface
vessels getting underway and while underway.
------------------------------------------------------------------------

Table 69--Mitigation for Unmanned Vehicles
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: Unmanned Surface Vehicles and Unmanned Underwater
Vehicles already being escorted (and operated under positive control)
by a manned surface support vessel.
------------------------------------------------------------------------
Mitigation Zones:
[cir] A surface support vessel that is already participating in
the event, and has positive control over the unmanned vehicle,
must maneuver the unmanned vehicle (which may include reducing
its speed) to ensure it maintains the following distances as
mission and circumstances allow:
[ssquf] 500 yd (457.2 m) from whales.
[ssquf] 200 yd (182.9 m) from other marine mammals.
Mitigation Requirements:
[cir] One Lookout on a surface support vessel that is already
participating in the event, and has positive control over the
unmanned vehicle.
Mitigation Requirement Timing:
[cir] Action Proponent personnel must observe the mitigation
zone for marine mammals immediately prior to unmanned vehicles
getting underway and while underway, the Lookout must observe.
------------------------------------------------------------------------

[[Page 19998]]

Table 70--Mitigation for Towed In-Water Devices
------------------------------------------------------------------------

-------------------------------------------------------------------------
Stressor or Activity: In-water devices towed by an aircraft, a manned
surface vessel, or an Unmanned Surface Vehicle or Unmanned Underwater
Vehicle already being escorted (and operated under positive control) by
a manned surface vessel.
------------------------------------------------------------------------
Mitigation Zone:
[cir] Manned towing platforms, or surface support vessels
already participating in the event that have positive control
over an unmanned vehicle that is towing an in-water device,
must maneuver itself or the unmanned vehicle (which may include
reducing speed) to ensure towed in-water devices maintain the
following distances as mission and circumstances allow:
[ssquf] 250 yd (228.6 m) from marine mammals.
Mitigation Requirements:
[cir] One Lookout on the manned towing vessel, or on a surface
support vessel that is already participating in the event and
has positive control over an unmanned vehicle that is towing an
in-water device.
Mitigation Requirement Timing:
[cir] Action Proponent personnel must observe the mitigation
zone for marine mammals immediately prior to and while in-water
devices are being towed.
------------------------------------------------------------------------

Geographic Mitigation Areas

In addition to activity-based mitigation, the Action Proponents
would implement mitigation measures within mitigation areas to avoid or
minimize potential impacts on marine mammals (see figure 11.6-1 of the
application). A full technical analysis of the mitigation areas that
the Action Proponents considered for marine mammals is provided in
section 5.7 (Geographic Mitigation) of the 2024 AFTT Draft Supplemental
EIS/OEIS. The Action Proponents took into account public comments
received on the 2018 AFTT Draft EIS/OEIS, the best available science,
and the practicability of implementing additional mitigation measures
and has enhanced its mitigation areas and mitigation measures beyond
those that were included in the 2018-2025 regulations to further reduce
impacts to marine mammals.
Information on the mitigation measures that the Action Proponents
propose to implement within mitigation areas are provided in table 71
through table 78. The mitigation applies year-round unless specified
otherwise in the tables.
NMFS conducted an independent analysis of the mitigation areas that
the Action Proponent proposed, which are described below. NMFS
preliminarily concurs with the Action Proponents' analysis, which
indicates that the measures in these mitigation areas are both
practicable and will reduce the likelihood, magnitude, or severity of
adverse impacts to marine mammals or their habitat in the manner
described in the Action Proponents' analysis and this rule. NMFS is
heavily reliant on the Action Proponents' description of operational
practicability, since the Action Proponents are best equipped to
describe the degree to which a given mitigation measure affects
personnel safety or mission effectiveness, and is practical to
implement. The Action Proponents consider the measures in this proposed
rule to be practicable, and NMFS concurs. We further discuss the manner
in which the Geographic Mitigation Areas in the proposed rule will
reduce the likelihood, magnitude, or severity of adverse impacts to
marine mammal species or their habitat in the Preliminary Analysis and
Negligible Impact Determination section.
Table 71 details geographic mitigation related to ship shock
trials, which involve the use of explosives. Ship shock trials are
conducted only within established ship shock trial boxes within the
Gulf of America and overlapping the Jacksonville OPAREA. The boundaries
of the mitigation areas match the boundaries of each ship shock trial
box. Mitigation is a continuation of existing measures, except for new
mitigation related to the location of the northern Gulf of America ship
shock trial box as described in table 71.

Table 71--Ship Shock Trial Mitigation Area
----------------------------------------------------------------------------------------------------------------
Category Mitigation requirements Mitigation benefits
----------------------------------------------------------------------------------------------------------------
Explosives........................... Navy personnel must not conduct ship shock Prior to being repositioned,
trials within the portion of the ship the northern Gulf of America
shock trial box that overlaps the ship shock trial box
Jacksonville OPAREA from November 15 overlapped the Rice's whale
through April 15. core distribution area.
Pre-event planning for ship shock trials Preliminary Navy Acoustic
must include the selection of one primary Effects Model data indicated
and two secondary sites (within one of that Rice's whales would
the ship shock trial boxes) where marine have potentially been
mammal abundance is expected to be the exposed to AUD INJ, TTS, and
lowest during an event, with the primary behavioral impacts from
and secondary locations located more than explosives if events were to
2 nmi (3.7 km) from the western boundary occur at that location. Navy
of the Gulf Stream for events planned personnel determined it
within the portion of the ship shock would be practicable to
trial box that overlaps the Jacksonville reposition the ship shock
OPAREA. trial box outside of the
If Navy personnel determine during pre- Rice's whale core
event visual observations that the distribution area, and into
primary site is environmentally a new location that would
unsuitable (e.g., continuous observations avoid potential exposure of
of marine mammals), they would evaluate Rice's whales to injurious
the potential to move the event to one of levels of sound. The
the secondary sites in accordance with repositioned ship shock
the event-specific mitigation and trial box is now located off
monitoring plan (see table 11.5-2 of the the Naval Surface Warfare
application for additional information). Center, Panama City Division
Testing Range's southern
boundary.
Mitigation to not conduct
ship shock trials in the
Jacksonville OPAREA from
November 15 through April 15
is designed to avoid
potential injurious and
behavioral impacts on NARW
during calving season.
Mitigation to consider marine
mammal abundance during pre-
event planning, to
prioritize locations that
are more than 2 nmi (3.7 km)
from the western boundary of
the Gulf Stream (where
marine mammals would be
expected in greater
concentrations for foraging
and migration) when
conducting ship shock trials
in the boxes that overlap
the Jacksonville OPAREA, and
to evaluate the
environmental suitability of
the selected site based on
pre-event observations, are
collectively designed to
reduce the number of
individual marine mammals
exposed, as well as the
level of impact that could
potentially be received by
each animal.

[[Page 19999]]

.......................................... The benefits of the
mitigation for Rice's
whales, NARW, and other
marine mammal species would
be substantial because ship
shock trials use the largest
NEW of any explosive
activity conducted under the
Proposed Action.
----------------------------------------------------------------------------------------------------------------

Table 72 details geographic mitigation related to MTEs (i.e.,
Composite Training Unit Exercises and Sustainment Exercises).
Mitigation is a continuation of existing measures.

Table 72--Major Training Exercise Planning Awareness Mitigation Area
----------------------------------------------------------------------------------------------------------------
Category Mitigation requirements Mitigation benefits
----------------------------------------------------------------------------------------------------------------
Acoustic, Explosives, Physical Northeast: Within Major Training Exercise Mitigation to prohibit or
disturbance and strike. Planning Awareness Mitigation Areas limit MTEs within regional
located in the Northeast (i.e., the planning mitigation areas is
combined areas within the Gulf of Maine, collectively designed to
over the continental shelves off Long reduce the number of marine
Island, Rhode Island, Massachusetts, and mammal species, and
Maine), the Action Proponents must not individuals within each
conduct any full or partial MTEs. species, that are exposed to
Mid-Atlantic: Within Major Training potential impacts from
Exercise Planning Awareness Mitigation active sonar during MTEs.
Areas located in the Mid-Atlantic (i.e., The mitigation areas are
the combined areas off Maryland, situated among highly
Delaware, and North Carolina), the Action productive environments and
Proponents must avoid conducting any full persistent oceanographic
or partial MTEs to the maximum extent features associated with
practical, and must not conduct more than upwelling, steep bathymetric
four full or partial MTEs per year. contours, and canyons. The
areas have high marine
mammal densities, abundance,
or concentrated use for
feeding, reproduction, or
migration. Mitigation
benefits would be
substantial because MTEs are
conducted on a larger scale
and with more hours of
active sonar use than other
types of active sonar
events.
Mitigation for the Northeast
planning areas (including in
the Gulf of Maine) is
designed to prevent MTEs
from occurring within NARW
foraging critical habitat,
across the shelf break in
the northeast, on Georges
Bank, and in areas that
contain underwater canyons
(e.g., Hydrographer Canyon).
These locations (including
within a portion of the
Northeast Canyons and
Seamounts National Marine
Monument) have been
associated with high
occurrences of marine mammal
feeding, abundance, or
mating for harbor porpoises
and humpback, minke, sei,
fin, and NARW.
.......................................... Mitigation for the Mid-
Atlantic planning areas is
designed to limit the number
of MTEs that could occur
within large swaths of shelf
break that contain
underwater canyons or other
habitats (e.g., Norfolk
Canyon, part of the Cape
Hatteras Special Research
Area) associated with high
marine mammal diversity in
this region, including blue,
fin, minke, sei, sperm,
beaked, dwarf sperm, pygmy
sperm, and humpback whales,
as well as Risso's dolphins
and other delphinid species.
The planning areas also
overlap NARW migration
habitats.
----------------------------------------------------------------------------------------------------------------

Table 73 details geographic mitigation related to active sonar and
explosives (and special reporting for their use), and physical
disturbance and strike stressors off the northeastern United States.
The mitigation area extent matches that of the NARW foraging critical
habitat designated in 2016 (81 FR 4838, February 26, 2016). Mitigation
is a continuation of existing measures, with clarification that
requirements pertain to in-water stressors (i.e., not activities with
no potential marine mammal impacts, such as air-to-air activities).
Mitigation is designed to protect individual NARW within their foraging
critical habitat. Mitigation will also protect individuals of other
species whose biologically significant habitats overlap the mitigation
area, including harbor porpoises and humpback, minke, sei, and fin
whales. Special reporting for the use of acoustics and explosives is
also required for this area (see Proposed Reporting section for
details).

Table 73--Northeast North Atlantic Right Whale Mitigation Area
----------------------------------------------------------------------------------------------------------------
Category Mitigation requirements Mitigation benefits
----------------------------------------------------------------------------------------------------------------
Acoustic............................. The Action Proponents must minimize the Mitigation is designed to
use of low-frequency active sonar, mid- minimize exposure of NARW to
frequency active sonar, and high- sounds with potential for
frequency active sonar in the mitigation injury or behavioral
area to the maximum extent practical. impacts.
Explosives........................... The Action Proponents must not detonate in- Mitigation is designed to
water explosives (including underwater prevent exposure of NARW to
explosives and explosives deployed explosives with potential
against surface targets) within the for injury, mortality, or
mitigation area. behavioral impacts.
The Action Proponents must not detonate Mitigation to prohibit
explosive sonobuoys within 3 nmi (5.6 km) explosive sonobuoys within 3
of the mitigation area. nmi (5.6 km) is designed to
further prevent exposure to
large and dispersed
explosive sonobuoy fields.

[[Page 20000]]

Physical disturbance and strike...... The Action Proponents must not use non- Mitigation to prohibit use of
explosive bombs within the mitigation non-explosive bombs is
area. designed to reduce the
During non-explosive torpedoes events potential for NARW to be
within the mitigation area: struck by non-explosive
--The Action Proponents must conduct ordnance.
activities during daylight hours in Mitigation to conduct non-
Beaufort sea state 3 or less. explosive torpedo activities
--In addition to Lookouts required as during daylight hours in
described in section 11.5 of the Beaufort sea state 3 or
application, the Action Proponents must less, and to post additional
post two Lookouts in an aircraft during Lookouts from aircraft (and
dedicated aerial surveys, and one Lookout submarines, when surfaced),
on the submarine participating in the is designed to improve
event (when surfaced). Lookouts must marine mammal sightability
begin conducting visual observations during visual observations.
immediately prior to the start of an Mitigation for vessels to
event. If floating vegetation or marine obtain sightings information
mammals are observed in the event from the North Atlantic
vicinity, the event must not commence Right Whale Sighting
until the vicinity is clear or the event Advisory System and
is relocated to an area where the implement speed reductions
vicinity is clear. Lookouts must continue in certain circumstances is
to conduct visual observations during the designed to reduce the
event. If marine mammals are observed in potential for vessels to
the vicinity, the event must cease until encounter NARW. The North
one of the Mitigation Zone All-Clear Atlantic Right Whale
Conditions has been met as described in Sighting Advisory System is
section 11.5 of the application. a NOAA Northeast Fisheries
--During transits and normal firing, Science Center program that
surface ships must maintain a speed of no collects sightings
more than 10 kn (18.5 km/hr); during information off the
submarine target firing, surface ships northeastern United States
must maintain speeds of no more than 18 from aerial surveys,
kn (33.3 km/hr); and during vessel target shipboard surveys, whale
firing, surface ship speeds may exceed 18 watching vessels, and
kn (33.3 km/hr) for brief periods of time opportunistic sources, such
(e.g., 10-15 minutes). as the Coast Guard,
commercial ships, fishing
vessels, and the public.
For vessel transits within the mitigation
area:
--The Action Proponents must conduct a web
query or e-mail inquiry to the North
Atlantic Right Whale Sighting Advisory
System or WhaleMap (https://whalemap.org/
) to obtain the latest NARW sightings
data prior to transiting the mitigation
area. The Action Proponents must provide
Lookouts the sightings data prior to
standing watch. Lookouts must use that
data to help inform visual observations
during vessel transits.
Surface ships must implement speed
reductions after observing a NARW, if
transiting within 5 nmi (9.3 km) of a
sighting reported to the North Atlantic
Right Whale Sighting Advisory System
within the past week, and when transiting
at night or during periods of reduced
visibility.
----------------------------------------------------------------------------------------------------------------

Table 74 details geographic mitigation related to active sonar and
special reporting for the use of active sonar and in-water explosives
within the Gulf of Maine. Mitigation is a continuation of existing
measures. Special reporting for the use of acoustics and explosives is
also required for this area (see Proposed Reporting section for
details).

Table 74--Gulf of Maine Marine Mammal Mitigation Area
----------------------------------------------------------------------------------------------------------------
Category Mitigation requirements Mitigation benefits
----------------------------------------------------------------------------------------------------------------
Acoustic............................. The Action Proponents must not use more Mitigation is designed to
than 200 hours of surface ship hull- reduce exposure of NARW to
mounted mid-frequency active sonar potentially injurious levels
annually within the mitigation area. of sound from the type of
active sonar with the
highest source power used in
the Study Area within
foraging critical habitat
designated by NMFS in 2016
(81 FR 4838, February 26,
2016) and additional sea
space southward over Georges
Bank.
----------------------------------------------------------------------------------------------------------------

Table 75 details geographic mitigation related to active sonar and
explosives (and special reporting for their use), and physical
disturbance and strike stressors in the Jacksonville OPAREA. Mitigation
is a continuation of existing measures, with clarification that
requirements pertain to in-water stressors (i.e., not activities with
no potential marine mammal impacts, such as air-to-air activities).

Table 75--Jacksonville Operating Area North Atlantic Right Whale Mitigation Area
----------------------------------------------------------------------------------------------------------------
Category Mitigation requirements Mitigation benefits
----------------------------------------------------------------------------------------------------------------
Acoustic, explosives, and physical From November 15 to April 15 within the Mitigation is designed to
disturbance and vessel strike. mitigation area, prior to vessel transits minimize potential NARW-
or military readiness activities vessel interactions and
involving active sonar, in-water exposure to stressors with
explosives (including underwater the potential for mortality,
explosives and explosives deployed injury, or behavioral
against surface targets), or non- disturbance within the
explosive ordnance deployed against portions of the reproduction
surface targets (including aerial- (calving) critical habitat
deployed mines), the Action Proponents designated by NMFS in 2016
must initiate communication with Fleet (81 FR 4838) and important
Area Control and Surveillance Facility, migration habitat that
Jacksonville to obtain Early Warning overlaps the Jacksonville
System data. The facility must advise of OPAREA.
all reported NARW sightings in the The benefits of the
vicinity of planned vessel transits and mitigation would be
military readiness activities. substantial because the
--Sightings data must be used when Jacksonville OPAREA is an
planning event details (e.g., timing, Action Proponent
location, duration) to minimize concentration area within
interactions with NARW to the maximum the southeastern region.
extent practical.

[[Page 20001]]

The Action Proponents must provide
Lookouts the sightings data prior to
standing watch to help inform visual
observations.
----------------------------------------------------------------------------------------------------------------

Table 76 details geographic mitigation related to active sonar and
explosives (and special reporting for their use), and physical
disturbance and strike stressors off the Southeastern U.S. Mitigation
is a continuation of existing measures, with clarification that
requirements pertain to the use of in-water stressors (i.e., not
activities with no potential marine mammal impacts, such as air-to-air
activities). The mitigation area is the largest area practical to
implement within the NARW reproduction critical habitat designated by
NMFS in 2016 (81 FR 4838). Mitigation is designed to protect
reproductive mothers, calves, and mother-calf pairs within the only
known NARW calving habitat. Mitigation benefits would be substantial
because the mitigation area encompasses the Georgia and northeastern
Florida coastlines (where the highest seasonal concentrations occur)
and coastal extent of the Jacksonville OPAREA (an Action Proponent
concentration area). Special reporting for the use of acoustics and
explosives is also required for this area (see Proposed Reporting
section for details).

Table 76--Southeast North Atlantic Right Whale Mitigation Area
----------------------------------------------------------------------------------------------------------------
Category Mitigation requirements Mitigation benefits
----------------------------------------------------------------------------------------------------------------
Acoustic............................. From November 15 to April 15 within the Mitigation is designed to
mitigation area, the Action Proponents minimize exposure to levels
must not use high-frequency active sonar; of sound that have the
or low-frequency or mid-frequency active potential to cause injurious
sonar except: or behavioral impacts.
--To the maximum extent practical, the
Action Proponents must minimize use of
(1) helicopter dipping sonar (a mid-
frequency active sonar source) and (2)
low-frequency or surface ship hull-
mounted mid-frequency active sonar during
navigation training or object detection.
Explosives........................... From November 15 to April 15 within the Mitigation is designed to
mitigation area, the Action Proponents prevent exposure to
must not detonate in-water explosives explosives with the
(including underwater explosives and potential for injury,
explosives deployed against surface mortality, or behavioral
targets). disturbance.
Physical disturbance and vessel From November 15 to April 15 within the Mitigation is designed to
strike. mitigation area, the Action Proponents prevent strikes by non-
must not deploy non-explosive ordnance explosive ordnance, and to
against surface targets (including aerial- decrease the potential for
deployed mines). vessel strikes. North-south
From November 15 to April 15 within the transit restrictions are
mitigation area, surface ships must designed to reduce the time
minimize north-south transits to the ships spend in the highest
maximum extent practical, and must seasonal occurrence areas to
implement speed reductions after they further decrease vessel
observe a NARW, if they are within 5 nmi strike risk.
(9.3 km) of an Early Warning System
sighting reported within the past 12
hours, and at night and in poor
visibility.
Acoustic, explosives, and physical From November 15 to April 15 within the Mitigation is designed to
disturbance and vessel strike. mitigation area, prior to vessel transits minimize potential vessel
or military readiness activities interactions and exposure to
involving active sonar, in-water stressors with the potential
explosives (including underwater for mortality, injury, or
explosives and explosives deployed behavioral disturbance.
against surface targets), or non-
explosive ordnance deployed against
surface targets (including aerial-
deployed mines), the Action Proponents
must initiate communication with Fleet
Area Control and Surveillance Facility,
Jacksonville to obtain Early Warning
System sightings data. The facility must
advise of all reported NARW sightings in
the vicinity of planned vessel transits
and military readiness activities.
The Action Proponents must provide
Lookouts the sightings data prior to
standing watch to help inform visual
observations.
----------------------------------------------------------------------------------------------------------------

Table 77 details geographic mitigation related to active sonar,
explosives, and physical disturbance and strike stressors off the U.S.
east coast to the boundary of the U.S. EEZ. Mitigation is a
continuation of existing measures, with clarification that requirements
pertain to the use of in-water stressors (i.e., not activities with no
potential marine mammal impacts, such as air-to-air activities).

Table 77--Dynamic North Atlantic Right Whale Mitigation Areas
----------------------------------------------------------------------------------------------------------------
Category Mitigation requirements Mitigation benefits
----------------------------------------------------------------------------------------------------------------
Acoustic, explosives, and physical The applicable dates and locations of this The mitigation area extent
disturbance and vessel strike. mitigation area must correspond with matches the boundary of the
NMFS' Dynamic Management Areas, which U.S. EEZ on the East Coast,
fluctuate throughout the year based on which is the full extent of
the locations and timing of confirmed where Dynamic Management
NARW detections. Areas could potentially be
The Action Proponents must provide NARW established year-round. NMFS
Dynamic Management Area information manages the Dynamic
(e.g., location and dates) to applicable Management Areas program off
assets transiting and training or testing the U.S. East Coast with the
in the vicinity of the Dynamic Management primary goal of reducing the
Area. likelihood of NARW vessel
--The broadcast awareness notification strikes from all mariners.
messages must alert assets (and their Mitigation is designed to
Lookouts) to the possible presence of minimize potential NARW
NARW in their vicinity. vessel interactions and
exposure to acoustic
stressors, explosives, and
physical disturbance and
strike stressors that have
the potential to cause
mortality, injury, or
behavioral disturbance.

[[Page 20002]]

Lookouts must use the information to help
inform visual observations during
military readiness activities that
involve vessel movements, active sonar,
in-water explosives (including underwater
explosives and explosives deployed
against surface targets), or non-
explosive ordnance deployed against
surface targets in the mitigation area.
----------------------------------------------------------------------------------------------------------------

Table 78 details geographic mitigation related to active sonar and
explosives (and special reporting for their use) in the northeastern
Gulf of America. Mitigation is a continuation of existing measures. The
mitigation area extent aligns with this species' small and resident
population area identified by NMFS in its 2016 status review (Rosel et
al., 2016). Special reporting for the use of acoustics and explosives
is also required for this area (see Proposed Reporting section for
details).

Table 78--Rice's Whale Mitigation Area
----------------------------------------------------------------------------------------------------------------
Category Mitigation requirements Mitigation benefits
----------------------------------------------------------------------------------------------------------------
Acoustic............................. The Action Proponents must not use more Mitigation is designed to
than 200 hours of surface ship hull- reduce exposure of
mounted mid-frequency active sonar individuals within the small
annually within the mitigation area. and resident population of
Rice's whales to potentially
injurious levels of sound by
the type of active sonar
with the highest source
power used in the Study
Area.
Explosives........................... Except during mine warfare activities, the Mitigation is designed to
Action Proponents must not detonate in- reduce exposure of
water explosives (including underwater individuals within the small
explosives and explosives deployed and resident population of
against surface targets) within the Rice's whales to explosives
mitigation area. that have the potential to
cause injury, mortality, or
behavioral disturbance.
----------------------------------------------------------------------------------------------------------------

Mitigation Conclusions

NMFS has carefully evaluated the Action Proponents' proposed
mitigation measures--many of which were developed with NMFS' input
during the previous phases of AFTT authorizations but several of which
are new since implementation of the 2018 to 2025 regulations--and
considered a broad range of other measures (i.e., the measures
considered but eliminated in the 2018 AFTT Final EIS/OEIS, which
reflect many of the comments that have arisen from public input or
through discussion with NMFS in past years) in the context of ensuring
that NMFS prescribes the means of effecting the least practicable
adverse impact on the affected marine mammal species and their habitat.
Our evaluation of potential measures included consideration of the
following factors in relation to one another: the manner in which, and
the degree to which, the successful implementation of the mitigation
measures is expected to reduce the likelihood and/or magnitude of
adverse impacts to marine mammal species and their habitat; the proven
or likely efficacy of the measures; and the practicability of the
measures for applicant implementation, including consideration of
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
Based on our evaluation of the Action Proponents' proposed
measures, as well as other measures considered by the Action Proponents
and NMFS (see section 5.9 (Measures Considered but Eliminated) of
chapter 5 (Mitigation) of the 2024 AFTT Draft Supplemental EIS/OEIS),
NMFS has preliminarily determined that these proposed mitigation
measures are appropriate means of effecting the least practicable
adverse impact on marine mammal species and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and considering specifically personnel safety,
practicality of implementation, and impact on the effectiveness of the
military readiness activity. Additionally, an adaptive management
component helps further ensure that mitigation is regularly assessed
and provides a mechanism to improve the mitigation, based on the
factors above, through modification as appropriate.
The proposed rule comment period provides the public an opportunity
to submit recommendations, views, and/or concerns regarding the Action
Proponents' activities and the proposed mitigation measures. While NMFS
has preliminarily determined that the Action Proponents' proposed
mitigation measures would effect the least practicable adverse impact
on the affected species and their habitat, NMFS will consider all
public comments to help inform our final determination. Consequently,
proposed mitigation measures may be refined, modified, removed, or
added prior to the issuance of the final rule based on public comments
received and, as appropriate, analysis of additional potential
mitigation measures.

Proposed Monitoring

Section 101(a)(5)(A) of the MMPA states that in order to authorize
incidental take for an activity, NMFS must set forth requirements
pertaining to the monitoring and reporting of such taking. The MMPA
implementing regulations at 50 CFR 216.104(a)(13) indicate that
requests for incidental take authorizations must include the suggested
means of accomplishing the necessary monitoring and reporting that will
result in increased knowledge of the species and of the level of taking
or impacts on populations of marine mammals that are expected to be
present.
Although the Navy has been conducting research and monitoring for
over 20 years in areas where it has been training, it developed a
formal marine species monitoring program in support of the AFTT Study
Area MMPA and ESA processes in 2009. Across all Navy training and
testing study areas, the robust marine species monitoring program has
resulted in hundreds of technical reports and publications on marine
mammals that have informed Navy and NMFS analyses in environmental
planning documents, rules, and Biological Opinions. The reports are
made available to the public on the Navy's marine species monitoring
website (www.navymarinespeciesmonitoring.us) and the data on the Ocean
Biogeographic Information System

[[Page 20003]]

Spatial Ecological Analysis of Megavertebrate Populations (OBIS-SEAMAP)
(https://seamap.env.duke.edu/).
The Navy would continue collecting monitoring data to inform our
understanding of the occurrence of marine mammals in the AFTT Study
Area; the likely exposure of marine mammals to stressors of concern in
the AFTT Study Area; the response of marine mammals to exposures to
stressors; the consequences of a particular marine mammal response to
their individual fitness and, ultimately, populations; and the
effectiveness of implemented mitigation measures. Taken together,
mitigation and monitoring comprise the Navy's integrated approach for
reducing environmental impacts from the specified activities. The
Navy's overall monitoring approach seeks to leverage and build on
existing research efforts whenever possible.
As agreed upon between the Action Proponents and NMFS, the
monitoring measures presented here, as well as the mitigation measures
described above, focus on the protection and management of potentially
affected marine mammals. A well-designed monitoring program can provide
important feedback for validating assumptions made in analyses and
allow for adaptive management of marine mammals and their habitat, and
other marine resources. Monitoring is required under the MMPA, and
details of the monitoring program for the specified activities have
been developed through coordination between NMFS and the Action
Proponents through the regulatory process for previous Navy at-sea
training and testing activities.

Navy Marine Species Research and Monitoring Strategic Framework

The initial structure for the U.S. Navy's marine species monitoring
efforts was developed in 2009 with the Integrated Comprehensive
Monitoring Program (ICMP). The intent of the ICMP was to provide an
overarching framework for coordination of the Navy's monitoring efforts
during the early years of the program's establishment. A Strategic
Planning Process (U.S. Department of the Navy, 2013) was subsequently
developed and together with the ICMP framework serves as a planning
tool to focus marine species monitoring priorities defined by ESA and
MMPA requirements, and to coordinate monitoring efforts across regions
based on a set of common objectives. Using an underlying conceptual
framework incorporating a progression of knowledge from occurrence to
exposure/response, and ultimately consequences, the Strategic Planning
Process was developed as a tool to help guide the investment of
resources to address top level objectives and goals of the monitoring
program most efficiently. The Strategic Planning Process identifies
Intermediate Scientific Objectives, which form the basis of evaluating,
prioritizing, and selecting new monitoring projects or investment
topics and serve as the basis for developing and executing new
monitoring projects across the Navy's training and testing ranges (both
Atlantic and Pacific).
Monitoring activities relating to the effects of military readiness
activities on marine species are generally designed address one or more
of the following top-level goals:
(i) An increase in the understanding of the likely occurrence of
marine mammals and ESA-listed marine species in the vicinity of the
action (i.e., presence, abundance, distribution, and density);
(ii) An increase in the understanding of the nature, scope, or
context of the likely exposure of marine mammals and ESA-listed species
to any of the potential stressors associated with the action (e.g.,
sound, explosive detonation, or military expended materials), through
better understanding of one or more of the following:
A. The nature of the action and its surrounding environment (e.g.,
sound-source characterization, propagation, and ambient noise levels),
B. The affected species (e.g., life history or dive patterns),
C. The likely co-occurrence of marine mammals and ESA-listed marine
species with the action (in whole or part), or
D. The likely biological or behavioral context of exposure to the
stressor for the marine mammal and ESA-listed marine species (e.g., age
class of exposed animals or known pupping, calving, or feeding areas).
(iii) An increase in the understanding of how individual marine
mammals or ESA-listed marine species respond (behaviorally or
physiologically) to the specific stressors associated with the action
(in specific contexts, where possible (e.g., at what distance or
received level)).
(iv) An increase in the understanding of how anticipated individual
responses, to individual stressors or anticipated combinations of
stressors, may impact either:
A. The long-term fitness and survival of an individual; or
B. The population, species, or stock (e.g., through impacts on
annual rates of recruitment or survival).
(v) An increase in the understanding of the effectiveness of
mitigation and monitoring measures.
(vi) A better understanding and record of the manner in which the
authorized entity complies with the Incidental Take Authorization and
Incidental Take Statement.
(vii) An increase in the probability of detecting marine mammals
(through improved technology or methods), both specifically within the
mitigation zone (thus allowing for more effective implementation of the
mitigation) and in general, to better achieve the above goals; and
(viii) Ensuring that adverse impact of activities remains at the
least practicable level.
The Navy's Marine Species Monitoring Program investments are
evaluated through the Adaptive Management Review process to (1) assess
overall progress, (2) review goals and objectives, and (3) make
recommendations for refinement and evolution of the monitoring
program's focus and direction. The Marine Species Monitoring Program
has developed and matured significantly since its inception and now
supports a portfolio of several dozen active projects across a range of
geographic areas and protected species taxa addressing both regional
priorities (i.e., particular species of concern), and Navy-wide needs
such as the behavioral response of beaked whales to training and
testing activities.
A Research and Monitoring Summit was held in early 2023 to evaluate
the current state of the Marine Species Monitoring Program in terms of
progress, objectives, priorities, and needs, and to solicit valuable
input from meeting participants including NMFS, Marine Mammal
Commission, Navy, and scientific experts. The overarching goal of the
summit was to facilitate updating the ICMP framework for guiding marine
species research and monitoring investments, and to identify data gaps
and priorities to be addressed over the next 5-10 years across a range
of basic research through applied monitoring. One of the outcomes of
this summit meeting is a refreshed strategic framework effectively
replacing the ICMP which will provide increased coordination and
synergy across the Navy's protected marine species investment programs
(see section 13.1 of the application). This will contribute to the
collective goal of supporting improved assessment of effects from
training and testing activities through

[[Page 20004]]

development of first in class science and data.

Past and Current Action Proponent Monitoring in the AFTT Study Area

The Navy's monitoring program has undergone significant changes
since the first rule was issued for the AFTT Study Area in 2008 through
the process of adaptive management. The monitoring program developed
for the first cycle of environmental compliance documents (e.g., U.S.
Department of the Navy, 2008a, 2008b) utilized effort-based compliance
metrics that were somewhat limiting. Through adaptive management
discussions, the Navy designed and conducted monitoring studies
according to scientific objectives and eliminated specific effort
requirements.
Progress has also been made on the conceptual framework categories
from the Scientific Advisory Group for Navy Marine Species Monitoring
(U.S. Department of the Navy, 2011), ranging from occurrence of
animals, to their exposure, response, and population consequences. The
Navy continues to manage the Atlantic and Pacific program as a whole,
with monitoring in each range complex taking a slightly different but
complementary approach. The Navy has continued to use the approach of
layering multiple simultaneous components in many of the range
complexes to leverage an increase in return of the progress toward
answering scientific monitoring questions. This includes in the AFTT
Study Area, for example, (a) Analysis of Acoustic Ecology of North
Atlantic Shelf Break Cetaceans and Effects of Anthropogenic Noise
Impacts; (b) Mid-Atlantic Nearshore and Mid-shelf Baleen Whale
Monitoring; (c) Atlantic Behavioral Response Study; and (d) Occurrence
of Rice's Whale in the Northeastern Gulf of America.
Numerous publications, dissertations, and conference presentations
have resulted from research conducted under the marine species
monitoring program (https://www.navymarinespeciesmonitoring.us/reading-room/), leading to a significant contribution to the body of marine
mammal science. Publications on occurrence, distribution, and density
have fed the modeling input, and publications on exposure and response
have informed Navy and NMFS analysis of behavioral response and
consideration of mitigation measures.
Furthermore, collaboration between the monitoring program and the
Navy's research and development (e.g., the ONR) and demonstration-
validation (e.g., Living Marine Resources (LMR)) programs has been
strengthened, leading to research tools and products that have already
transitioned to the monitoring program. These include Marine Mammal
Monitoring on Ranges, controlled exposure experiment behavioral
response studies, acoustic sea glider surveys, and global positioning
system-enabled satellite tags. Recent progress has been made with
better integration with monitoring across all Navy at-sea study areas,
including the AFTT Study Area and various other ranges. Publications
from the LMR and ONR programs have also resulted in significant
contributions to hearing, acoustic criteria used in effects modeling,
exposure, and response, as well as in developing tools to assess
biological significance (e.g., consequences).
NMFS and the Navy also consider data collected during mitigations
as monitoring. Data are collected by shipboard personnel on hours spent
training, hours of observation, hours of sonar, and marine mammals
observed within the mitigation zones when mitigations are implemented.
These data are provided to NMFS in both classified and unclassified
annual exercise reports, which would continue under this proposed rule.
NMFS has received multiple years' worth of annual exercise and
monitoring reports addressing active sonar use and explosive
detonations within the AFTT Study Area and other Navy range complexes.
The data and information contained in these reports have been
considered in developing mitigation and monitoring measures for the
proposed military readiness activities within the AFTT Study Area. The
Navy's annual exercise and monitoring reports may be viewed at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities and https://www.navymarinespeciesmonitoring.us/reporting/.
The Navy's marine species monitoring program supports several
monitoring projects in the AFTT Study Area at any given time.
Additional details on the scientific objectives for each project can be
found at: https://www.navymarinespeciesmonitoring.us/regions/atlantic/current-projects/. Projects can be either major multi-year efforts, or
1 to 2-year special studies. The emphasis on monitoring in the AFTT
Study Area is to improve understanding of the occurrence and
distribution of protected marine species within the AFTT Study Area,
improve understanding of their exposure and response to sonar and
explosives training and testing activities, and ultimately inform
decision makers of the consequences of that exposure.
Specific monitoring under the 2018-2025 regulations included the
following projects:
(i) Atlantic Behavioral Response Study;
(ii) Behavioral Response Analysis of Two Populations of Short-
Finned Pilot Whales to Mid-Frequency Active Sonar;
(iii) Behavioral Response of Humpback Whales to Vessel Traffic;
(iv) Analysis of Acoustic Ecology of North Atlantic Shelf Break
Cetaceans and Effects of Anthropogenic Noise Impacts;
(v) North Atlantic Right Whale Monitoring, Conservation, and
Protection;
(vi) Atlantic Marine Assessment Program for Protected Species
(AMAPPS);
(vii) Haul-Out Counts and Photo-Identification of Pinnipeds in
Virginia;
(viii) Time-lapse Camera Surveys of Pinnipeds in Southeastern
Virginia;
(ix) Pinniped Monitoring in the Northeast;
(x) Jacksonville Shallow Water Training Range Vessel Surveys;
(xi) Mid-Atlantic Autonomous Passive Acoustic Monitoring;
(xii) Mid-Atlantic Nearshore & Mid-shelf Baleen Whale Monitoring;
(xiii) Mid-Atlantic Offshore Cetacean Study; and
(xiv) Occurrence of Rice's Whale in the Northeastern Gulf of
America.
Future monitoring efforts by the Action Proponents in the AFTT
Study Area are anticipated to continue along the same objectives:
establish the baseline habitat uses and movement patterns; establish
the baseline behavior (foraging, dive patterns, etc.); evaluate
potential exposure and behavioral responses of marine mammals exposed
to training and testing activities, and support conservation and
management of NARWs.
Currently planned monitoring projects and their Intermediate
Scientific Objective for the 2025-2032 rule are listed below, many of
which are continuations of projects currently underway. Other than
those ongoing projects, monitoring projects are typically planned one
year in advance; therefore, this list does not include all projects
that will occur over the entire period of the rule.
(i) Atlantic Behavioral Response Study (ongoing)--The objective is
to evaluate behavioral responses of marine mammals exposed to Navy
training and testing activities.
(ii) Behavioral Response Analysis of Two Populations of Short-
Finned Pilot Whales to Mid-Frequency Active Sonar

[[Page 20005]]

(ongoing)--The objective is to evaluate behavioral responses of marine
mammals exposed to Navy training and testing activities.
(iii) Analysis of Acoustic Ecology of North Atlantic Shelf Break
Cetaceans and Effects of Anthropogenic Noise Impacts (ongoing)--The
objectives are to (1) establish the baseline vocalization behavior of
marine mammals where Navy training and testing activities occur; and
(2) evaluate trends in distribution and abundance of populations that
are regularly exposed to sonar and underwater explosives.
(iv) North Atlantic Right Whale Monitoring, Conservation, and
Protection (ongoing)--The objectives are to (1) Establish the baseline
habitat uses and movement patterns of marine mammals where Navy
training and testing activities occur; and (2) establish the baseline
behavior (foraging, dive patterns, etc.) of marine mammals where Navy
training and testing activities occur.
(v) Haul-Out Counts and Photo-Identification of Pinnipeds in
Virginia (ongoing)--The objectives are to (1) estimate the density of
marine mammals and sea turtles in Navy range complexes and in specific
training areas; (2) establish the baseline habitat uses and movement
patterns of marine mammals and sea turtles where Navy training and
testing activities occur; and (3) evaluate trends in distribution and
abundance of populations that are regularly exposed to sonar and
underwater explosives.
(vi) Time-lapse Camera Surveys of Pinnipeds in Southeastern
Virginia (ongoing)--The objectives are to (1) estimate the density of
marine mammals and sea turtles in Navy range complexes and in specific
training areas; (2) establish the baseline habitat uses and movement
patterns of marine mammals and sea turtles where Navy training and
testing activities occur; and (3) evaluate trends in distribution and
abundance of populations that are regularly exposed to sonar and
underwater explosives.
(vii) Jacksonville Shallow Water Training Range Vessel Surveys
(ongoing)--The objectives are to (1) establish the baseline habitat
uses and movement patterns of marine mammals and sea turtles where Navy
training and testing activities occur; (2) determine what populations
of marine mammals are exposed to Navy training and testing activities;
and (3) evaluate trends in distribution and abundance of populations
that are regularly exposed to Navy training and testing activities.
(viii) Mid-Atlantic Autonomous Passive Acoustic Monitoring
(ongoing)--The objectives are to (1) establish the baseline habitat
uses and movement patterns of marine mammals where Navy training and
testing activities occur; and (2) establish the baseline behavior
(foraging, dive patterns, etc.) of marine mammals where Navy training
and testing activities occur.
(ix) Mid-Atlantic Nearshore & Mid-shelf Baleen Whale Monitoring
(ongoing)--The objectives are to (1) establish the baseline habitat
uses and movement patterns of marine mammals where Navy training and
testing activities occur; (2) establish the baseline behavior
(foraging, dive patterns, etc.) of marine mammals where Navy training
and testing activities occur; and (3) support conservation and
management of North Atlantic right whales.
(x) Mid-Atlantic Offshore Cetacean Study (ongoing)--The objectives
are to (1) establish the baseline habitat uses and movement patterns of
marine mammals where Navy training and testing activities occur; and
(2) establish the baseline behavior (foraging, dive patterns, etc.) of
marine mammals where Navy training and testing activities occur.

Adaptive Management

The proposed regulations governing the take of marine mammals
incidental to military readiness activities in the AFTT Study Area
contain an adaptive management component. Our understanding of the
effects of military readiness activities (e.g., acoustic and explosive
stressors) on marine mammals continues to evolve, which makes the
inclusion of an adaptive management component both valuable and
necessary within the context of 7-year regulations.
The reporting requirements associated with this rule are designed
to provide NMFS with monitoring data from the previous year to allow
NMFS to consider whether any changes to existing mitigation and
monitoring requirements are appropriate. The use of adaptive management
allows NMFS to consider new information from different sources to
determine (with input from the Action Proponents regarding
practicability) on an annual or biennial basis if mitigation or
monitoring measures should be modified (including additions or
deletions). Mitigation measures could be modified if new data suggests
that such modifications would have a reasonable likelihood of more
effectively accomplishing the goals of the mitigation and monitoring
and if the measures are practicable. If the modifications to the
mitigation, monitoring, or reporting measures are substantial, NMFS
would publish a notice of the planned LOAs in the Federal Register and
solicit public comment.
The following are some of the possible sources of applicable data
to be considered through the adaptive management process: (1) Results
from monitoring and exercise reports, as required by MMPA
authorizations; (2) compiled results of Navy-funded research and
development studies; (3) results from specific stranding
investigations; (4) results from general marine mammal and sound
research; and (5) any information which reveals that marine mammals may
have been taken in a manner, extent, or number not authorized by these
regulations or subsequent LOAs. The results from monitoring reports and
other studies may be viewed at https://www.navymarinespeciesmonitoring.us.

Proposed Reporting

In order to issue incidental take authorization for an activity,
section 101(a)(5)(A) of the MMPA states that NMFS must set forth
requirements pertaining to the monitoring and reporting of such taking.
Effective reporting is critical both to compliance as well as ensuring
that the most value is obtained from the required monitoring. Reports
from individual monitoring events, results of analyses, publications,
and periodic progress reports for specific monitoring projects will be
posted to the Navy's Marine Species Monitoring web portal: https://www.navymarinespeciesmonitoring.us.
There are several different reporting requirements for the Navy
pursuant to the current regulations. All of these reporting
requirements would be continued for the Navy under this proposed rule
for the 7-year period.

Special Reporting for Geographic Mitigation Areas

The following sections describe special reporting for geographic
mitigation areas that the Action Proponents must include in the Annual
AFTT Training and Testing Reports. Special reporting for these areas is
designed to aid the Action Proponents and NMFS in continuing to analyze
potential impacts of training and testing in the mitigation areas. In
addition to the mitigation area-specific requirements described below,
for all mitigation areas, should national security require the Action
Proponents to exceed the activity restrictions in a given mitigation
area, Action Proponent personnel must provide NMFS with advance
notification and include the information (e.g., sonar hours, explosives
usage, or restricted area use)

[[Page 20006]]

in its annual activity reports submitted to NMFS.
Northeast North Atlantic Right Whale Mitigation Area
The Action Proponents must report the total annual hours and counts
of active sonar and in-water explosives (including underwater
explosives and explosives deployed against surface targets) used in the
mitigation area.
Gulf of Maine Marine Mammal Mitigation Area
The Action Proponents must report the total annual hours and counts
of active sonar and in-water explosives (including underwater
explosives and explosives deployed against surface targets) used in the
mitigation area.
Southeast North Atlantic Right Whale Mitigation Area
The Action Proponents must report the total annual hours and counts
of active sonar and in-water explosives (including underwater
explosives and explosives deployed against surface targets) used in the
mitigation area from November 15 to April 15.
Southeast North Atlantic Right Whale Special Reporting Mitigation Area
The Action Proponents must report the total annual hours and counts
of active sonar and in-water explosives (including underwater
explosives and explosives deployed against surface targets) used within
the mitigation area from November 15 to April 15. The mitigation area
extent aligns with the boundaries of the North Atlantic right whale
critical habitat for reproduction designated by NMFS in 2016 (81 FR
4838, January 27, 2016).
Rice's Whale Mitigation Area
The Action Proponents must report the total annual hours and counts
of active sonar and in-water explosives (including underwater
explosives and explosives deployed against surface targets) used in the
mitigation area.
Notification of Injured, Live Stranded, or Dead Marine Mammals
The Action Proponents would consult the Notification and Reporting
Plan, which sets out notification, reporting, and other requirements
when injured, live stranded, or dead marine mammals are detected. The
Notification and Reporting Plan is available for review at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.

Annual AFTT Study Area Marine Species Monitoring Report

The Action Proponents would submit an annual AFTT Study Area marine
species monitoring report describing the implementation and results
from the previous calendar year. Data collection methods will be
standardized across range complexes and the AFTT Study Area to allow
for comparison in different geographic locations. The draft report must
be submitted to the Director of the Office of Protected Resources of
NMFS annually as specified in the LOAs. NMFS will submit comments or
questions on the report, if any, within 3 months of receipt. The report
will be considered final after the Action Proponents have addressed
NMFS' comments, or 3 months after submittal of the draft if NMFS does
not provide comments on the draft report. The report would describe
progress of knowledge made with respect to intermediate scientific
objectives within the AFTT Study Area associated with the ICMP. Similar
study questions would be treated together so that progress on each
topic can be summarized across all Navy ranges. The report need not
include analyses and content that do not provide direct assessment of
cumulative progress on the monitoring plan study questions.

Annual AFTT Training and Testing Reports

In the event that the analyzed sound levels were exceeded, the
Action Proponents would submit a preliminary report(s) detailing the
exceedance within 21 days after the anniversary date of issuance of the
LOAs. Regardless of whether analyzed sound levels were exceeded, the
Navy would submit a detailed report (AFTT Annual Training Exercise
Report and Testing Activity Report) and Coast Guard would submit a
detailed report (AFTT Annual Training Exercise Report) to NMFS annually
as specified in the LOAs. NMFS will submit comments or questions on the
reports, if any, within 1 month of receipt. The reports will be
considered final after the Action Proponents have addressed NMFS'
comments, or 1 month after submittal of the drafts if NMFS does not
provide comments on the draft reports. The annual report shall contain
information on MTEs, ship shock trials, SINKEX events, and a summary of
all sound sources used (total hours or quantity (per the LOA)) of each
bin of sonar or other non-impulsive source; total annual number of each
type of explosive exercises; and total annual expended/detonated rounds
(missiles, bombs, sonobuoys, etc.) for each explosive bin). The annual
reports will also contain cumulative sonar and explosive use quantity
from previous years' reports through the current year. Additionally, if
there were any changes to the sound source allowance in the reporting
year, or cumulatively, the reports would include a discussion of why
the change was made and include analysis to support how the change did
or did not affect the analysis in the 2024 AFTT Draft Supplemental EIS/
OEIS and MMPA final rule. The annual reports would also include the
details regarding specific requirements associated with specific
mitigation areas. The analysis in the detailed report would be based on
the accumulation of data from the current year's report and data
collected from previous annual reports. The detailed reports shall also
contain special reporting for the Northeast North Atlantic Right Whale
Mitigation Area, Gulf of Maine Marine Mammal Mitigation Area, Southeast
North Atlantic Right Whale Mitigation Area, and Rice's Whale Mitigation
Area, as described in the LOAs.

Other Reporting and Coordination

The Action Proponents would continue to report and coordinate with
NMFS for the following:
(i) Annual marine species monitoring technical review meetings that
also include researchers and the Marine Mammal Commission; and
(ii) Annual Adaptive Management meetings that also include the
Marine Mammal Commission (and could occur in conjunction with the
annual marine species monitoring technical review meetings).

Preliminary Analysis and Negligible Impact Determination

General Negligible Impact Analysis

Introduction
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
taken by Level A harassment or Level B harassment (as presented in
table 35,

[[Page 20007]]

table 36, and table 37), NMFS considers other factors, such as the
likely nature of any responses (e.g., intensity, duration) and the
context of any responses (e.g., critical reproductive time or location,
migration), as well as effects on habitat and the likely effectiveness
of the mitigation. We also assess the number, intensity, and context of
estimated takes by evaluating this information relative to population
status. Consistent with the 1989 preamble for NMFS' implementing
regulations (54 FR 40338, September 29, 1989), the impacts from other
past and ongoing anthropogenic activities are incorporated into this
analysis via their impacts on the environmental baseline (e.g., as
reflected in the regulatory status of the species, population size and
growth rate where known, other ongoing sources of human-caused
mortality, and ambient noise levels).
In the Estimated Take of Marine Mammals section, we identified the
subset of potential effects that would be expected to rise to the level
of takes both annually and over the 7-year period covered by this
proposed rule, and then identified the maximum number of takes we
believe could occur (mortality) or are reasonably expected to occur
(harassment) based on the methods described. The impact that any given
take will have is dependent on many case-specific factors that need to
be considered in the negligible impact analysis (e.g., the context of
behavioral exposures such as duration or intensity of a disturbance,
the health of impacted animals, the status of a species that incurs
fitness-level impacts to individuals, etc.). For this proposed rule we
evaluated the likely impacts of the enumerated maximum number of
harassment takes that are proposed for authorization and reasonably
expected to occur, in the context of the specific circumstances
surrounding these predicted takes. We also include a specific
assessment of serious injury or mortality (hereafter referred to as M/
SI) takes that could occur, as well as consideration of the traits and
statuses of the affected species and stocks. Last, we collectively
evaluated this information, as well as other more taxa-specific
information and mitigation measure effectiveness, in group-specific
assessments that support our negligible impact conclusions for each
stock or species. Because all of the Action Proponents' specified
activities would occur within the ranges of the marine mammal stocks
identified in the rule, all negligible impact analyses and
determinations are at the stock level (i.e., additional species-level
determinations are not needed).
Harassment
The specified activities reflect representative levels of military
readiness activities. The Description of the Proposed Activity section
describes annual activities. There may be some flexibility in the exact
number of hours, items, or detonations that may vary from year to year,
but take totals would not exceed the maximum annual totals and 7-year
totals indicated in table 35, table 36, and table 37. We base our
analysis and negligible impact determination on the maximum number of
takes that would be reasonably expected to occur annually and are
proposed to be authorized, although, as stated before, the number of
takes are only one part of the analysis, which includes extensive
qualitative consideration of other contextual factors that influence
the degree of impact of the takes on the affected individuals. To avoid
repetition, we provide some general analysis immediately below that
applies to all the species listed in table 35, table 36, and table 37,
given that some of the anticipated effects of the Action Proponents'
military readiness activities on marine mammals are expected to be
relatively similar in nature. Below that, we provide additional
information specific to Mysticetes, Odontocetes, and Pinnipeds and,
finally, break our analysis into species (and/or stocks), or groups of
species (and the associated stocks) where relevant similarities exist,
to provide more specific information related to the anticipated effects
on individuals of a specific stock or where there is information about
the status or structure of any species that would lead to a differing
assessment of the effects on the species or stock. Organizing our
analysis by grouping species or stocks that share common traits or that
will respond similarly to effects of the Action Proponents' activities
and then providing species- or stock-specific information allows us to
avoid duplication while assuring that we have analyzed the effects of
the specified activities on each affected species or stock.
The Action Proponents' harassment take request is based on one
model for pile driving, and a second model (NAEMO) for all other
acoustic stressors, which NMFS reviewed and concurs appropriately
estimate the maximum amount of harassment that is reasonably likely to
occur. As described in more detail above, NAEMO calculates sound energy
propagation from sonar and other transducers, air guns, and explosives
during military readiness activities; the sound or impulse received by
animat dosimeters representing marine mammals distributed in the area
around the modeled activity; and whether the sound or impulse energy
received by a marine mammal exceeds the thresholds for effects.
Assumptions in the Navy models intentionally err on the side of
overestimation when there are unknowns. The effects of the specified
activities are modeled as though they would occur regardless of
proximity to marine mammals, meaning that no activity-based mitigation
is considered (e.g., no power down or shut down). However, the modeling
does quantitatively consider the possibility that marine mammals would
avoid continued or repeated sound exposures to some degree, based on a
species' sensitivity to behavioral disturbance. Additionally, the sonar
modeling reflects some, but not all, of the geographic mitigation
measures. NMFS provided input to, independently reviewed, and concurred
with the Action Proponents on this process and the Action Proponents'
analysis, which is described in detail in section 6 of the application,
was used to quantify harassment takes for this rule.
The Action Proponents and NMFS anticipate more severe effects from
takes resulting from exposure to higher received levels (though this is
in no way a strictly linear relationship for behavioral effects
throughout species, individuals, or circumstances) and less severe
effects from takes resulting from exposure to lower received levels.
However, there is also growing evidence of the importance of distance
in predicting marine mammal behavioral response to sound--i.e., sounds
of a similar level emanating from a more distant source have been shown
to be less likely to elicit a response of equal magnitude (DeRuiter
2012). The estimated number of takes by Level A harassment and Level B
harassment does not equate to the number of individual animals the
Action Proponents expect to harass (which is lower), but rather to the
instances of take (i.e., exposures above the Level A harassment and
Level B harassment threshold) that are anticipated to occur over the 7-
year period. These instances may represent either brief exposures
(seconds or minutes) or, in some cases, longer durations of exposure
within a day. In some cases, an animal that incurs a single take by AUD
INJ or TTS may also experience a direct behavioral harassment from the
same exposure. Some individuals may experience multiple instances of
take (meaning over multiple days) over the course of the

[[Page 20008]]

year, which means that the number of individuals taken is smaller than
the total estimated takes. Generally speaking, the higher the number of
takes as compared to the population abundance, the more repeated takes
of individuals are likely, and the higher the actual percentage of
individuals in the population that are likely taken at least once in a
year. We look at this comparative metric (number of takes to population
abundance) to give us a relative sense of where a larger portion of a
species is being taken by the specified activities, where there is a
likelihood that the same individuals are being taken across multiple
days, and whether the number of days might be higher or more likely
sequential. Where the number of instances of take is less than 100
percent of the abundance, and there is no information to specifically
suggest that some subset of animals is known to congregate in an area
in which activities are regularly occurring (e.g., a small resident
population, takes occurring in a known important area such as a BIA, or
a large portion of the takes occurring in a certain region and season),
the overall likelihood and number of repeated takes is generally
considered low, as it could, on one extreme, mean that every take
represents a separate individual in the population being taken on one
day (a minimal impact to an individual) or, more likely, that some
smaller number of individuals are taken on one day annually and some
are taken on a few, not likely sequential, days annually, and of course
some are not taken at all.
In the ocean, the use of sonar and other active acoustic sources is
often transient and is unlikely to repeatedly expose the same
individual animals within a short period, for example within one
specific exercise. However, for some individuals of some species,
repeated exposures across different activities could occur over the
year, especially where events occur in generally the same area with
more resident species. In short, for some species, we expect that the
total anticipated takes represent exposures of a smaller number of
individuals of which some would be exposed multiple times, but based on
the nature of the specified activities and the movement patterns of
marine mammals, it is unlikely that individuals from most stocks would
be taken over more than a few days within a given year. This means that
even where repeated takes of individuals are likely to occur, they are
more likely to result from non-sequential exposures from different
activities, and, even if sequential, individual animals are not
predicted to be taken for more than several days in a row, at most. As
described elsewhere, the nature of the majority of the exposures would
be expected to be of a less severe nature, and based on the numbers, it
is likely that any individual exposed multiple times is still only
taken on a small percentage of the days of the year. The greater
likelihood is that not every individual is taken, or perhaps a smaller
subset is taken with a slightly higher average and larger variability
of highs and lows, but still with no reason to think that, for most
species or stocks, any individuals would be taken a significant portion
of the days of the year.
Physiological Stress Response
Some of the lower level physiological stress responses (e.g.,
orientation or startle response, change in respiration, change in heart
rate) discussed earlier would likely co-occur with the predicted
harassments, although these responses are more difficult to detect and
fewer data exist relating these responses to specific received levels
of sound. Level B harassment takes, then, may have a stress-related
physiological component as well; however, we would not expect the
Action Proponents' generally short-term, intermittent, and (typically
in the case of sonar) transitory activities to create conditions of
long-term continuous noise leading to long-term physiological stress
responses in marine mammals that could affect reproduction or survival.
Behavioral Response
The estimates calculated using the BRF do not differentiate between
the different types of behavioral responses that rise to the level of
Level B harassment. As described in the application, the Action
Proponents identified (with NMFS' input) that moderate behavioral
responses, as characterized in Southall et al. (2021), would be
considered a take. The behavioral responses predicted by the BRFs are
assumed to be moderate severity exposures (e.g., altered migration
paths or dive profiles, interrupted nursing, breeding or feeding, or
avoidance) that may last for the duration of an exposure. The Action
Proponents then compiled the available data indicating at what received
levels and distances those responses have occurred, and used the
indicated literature to build biphasic behavioral response curves and
cut-off conditions that are used to predict how many instances of Level
B behavioral harassment occur in a day (see the ``Criteria and
Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase
4)'' technical report (U.S. Department of the Navy, 2024)). Take
estimates alone do not provide information regarding the potential
fitness or other biological consequences of the responses on the
affected individuals. We therefore consider the available activity-
specific, environmental, and species-specific information to determine
the likely nature of the modeled behavioral responses and the potential
fitness consequences for affected individuals.
Use of sonar and other transducers would typically be transient and
temporary. The majority of acoustic effects to individual animals from
sonar and other active sound sources during military readiness
activities would be primarily from anti-submarine warfare events. It is
important to note although anti-submarine warfare is one of the warfare
areas of focus during MTEs, there are significant periods when active
anti-submarine warfare sonars are not in use. Nevertheless, behavioral
responses are assumed more likely to be significant during MTEs than
during other anti-submarine warfare activities due to the duration
(i.e., multiple days), scale (i.e., multiple sonar platforms), and use
of high-power hull-mounted sonar in the MTEs. In other words, in the
range of potential behavioral effects that might be expected as part of
a response that qualifies as an instance of Level B behavioral
harassment (which by nature of the way it is modeled/counted, occurs
within 1 day), the less severe end might include exposure to
comparatively lower levels of a sound, at a detectably greater distance
from the animal, for a few or several minutes, and that could result in
a behavioral response such as avoiding an area that an animal would
otherwise have chosen to move through or feed in for some amount of
time or breaking off one or a few feeding bouts. More severe effects
could occur when the animal gets close enough to the source to receive
a comparatively higher level, is exposed continuously to one source for
a longer time, or is exposed intermittently to different sources
throughout a day. Such effects might result in an animal having a more
severe flight response and leaving a larger area for a day or more or
potentially losing feeding opportunities for a day. However, such
severe behavioral effects are expected to occur infrequently.
To help assess this, for sonar (LFAS/MFAS/HFAS) used in the AFTT
Study Area, the Action Proponents provided information estimating the
instances of take by Level B harassment by behavioral disturbance under
each BRF

[[Page 20009]]

that would occur within 6-dB increments (discussed below in the Group
and Species-Specific Analyses section), and by distance in 5-km bins in
section 2.3.3 of appendix A to the application. As mentioned above, all
else being equal, an animal's exposure to a higher received level is
more likely to result in a behavioral response that is more likely to
lead to adverse effects, which could more likely accumulate to impacts
on reproductive success or survivorship of the animal, but other
contextual factors (e.g., distance, duration of exposure, and
behavioral state of the animals) are also important (Di Clemente et
al., 2018; Ellison et al., 2012; Moore and Barlow, 2013, Southall et
al., 2019, Wensveen et al., 2017, etc.). The majority of takes by Level
B harassment are expected to be in the form of comparatively milder
responses (i.e., lower-level exposures that still rise to the level of
take, but would likely be less severe along the continuum of responses
that qualify as take) of a generally shorter duration. We anticipate
more severe effects from takes when animals are exposed to higher
received levels of sound or at closer proximity to the source. Because
species belonging to taxa that share common characteristics are likely
to respond and be affected in similar ways, these discussions are
presented within each species group below in the Group and Species-
Specific Analyses section. As noted previously in this proposed rule,
behavioral response is likely highly variable between species,
individuals within a species, and context of the exposure.
Specifically, given a range of behavioral responses that may be
classified as Level B harassment, to the degree that higher received
levels of sound are expected to result in more severe behavioral
responses, only a smaller percentage of the anticipated Level B
harassment from the specified activities might result in more severe
responses (see the Group and Species-Specific Analyses section below
for more detailed information).
Diel Cycle
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing on a diel cycle (24-hour cycle). Behavioral
responses to noise exposure, when taking place in a biologically
important context, such as disruption of critical life functions,
displacement, or avoidance of important habitat, are more likely to be
significant if they last more than one diel cycle or recur on
subsequent days (Southall et al., 2007). Henderson et al. (2016) found
that ongoing smaller scale events had little to no impact on foraging
dives for Blainville's beaked whale, while multi-day training events
may decrease foraging behavior for Blainville's beaked whale (Manzano-
Roth et al., 2016). Consequently, a behavioral response lasting less
than one day and not recurring on subsequent days is not considered
severe unless it could directly affect reproduction or survival
(Southall et al., 2007). Note that there is a difference between
multiple-day substantive behavioral responses and multiple-day
anthropogenic activities. For example, just because an at-sea exercise
lasts for multiple days does not necessarily mean that individual
animals are either exposed to those exercises for multiple days or,
further, exposed in a manner resulting in a sustained multiple day
substantive behavioral response. Large multi-day Navy exercises, such
as anti-submarine warfare activities, typically include vessels moving
faster than while in transit (typically 10-15 kn (18.5-27.8 km/hr) or
higher) and generally cover large areas that are relatively far from
shore (typically more than 3 nmi (5.6 km) from shore) and in waters
greater than 600 ft (182.9 m) deep. Marine mammals are moving as well,
which would make it unlikely that the same animal could remain in the
immediate vicinity of the ship for the entire duration of the exercise.
Further, the Action Proponents do not necessarily operate active sonar
the entire time during an exercise. While it is certainly possible that
these sorts of exercises could overlap with individual marine mammals
multiple days in a row at levels above those anticipated to result in a
take, because of the factors mentioned above, it is considered unlikely
for the majority of takes. However, it is also worth noting that the
Action Proponents conduct many different types of noise-producing
activities over the course of the year and it is likely that some
marine mammals will be exposed to more than one activity and taken on
multiple days, even if they are not sequential.
Durations of Navy activities utilizing tactical sonar sources and
explosives vary and are fully described in chapter 2 of the 2024 AFTT
Draft Supplemental EIS/OEIS. Sonar used during anti-submarine warfare
would impart the greatest amount of acoustic energy of any category of
sonar and other transducers analyzed in the application and include
hull-mounted, towed, line array, sonobuoy, helicopter dipping, and
torpedo sonars. Most anti-submarine warfare sonars are MFAS (1-10 kHz);
however, some sources may use higher or lower frequencies. Anti-
submarine warfare training activities using hull-mounted sonar proposed
for the AFTT Study Area generally last for only a few hours. However,
anti-submarine warfare testing activities range from several hours, to
days, to more than 10 days for large integrated anti-submarine warfare
MTEs (see table 4 and table 5). For these multi-day exercises there
will typically be extended intervals of non-activity in between active
sonar periods. Because of the need to train in a large variety of
situations, the Navy conducts anti-submarine warfare training exercises
in varying locations. Given the average length and dynamic nature of
anti-submarine warfare exercises (times of sonar use) and typical
vessel speed, combined with the fact that the majority of the cetaceans
would not likely remain in proximity to the sound source, it is
unlikely that an animal would be exposed to LFAS/MFAS/HFAS at levels or
durations likely to result in a substantive response that would then be
carried on for more than one day or on successive days.
Most planned explosive events are instantaneous or scheduled to
occur over a short duration (less than 2 hours) and the explosive
component of these activities only lasts for minutes. Although
explosive exercises may sometimes be conducted in the same general
areas repeatedly, because of their short duration and the fact that
they are in the open ocean and animals can easily move away, it is
similarly unlikely that animals would be exposed for long, continuous
amounts of time, or demonstrate sustained behavioral responses.
Although SINKEXs may last for up to 48 hours (4-8 hours typically,
possibly 1-2 days), they are almost always completed in a single day
and only one event is planned annually for the AFTT Study Area (see
table 6). They are stationary and conducted in deep, open water (where
fewer marine mammals would typically be expected to be randomly
encountered), and they have rigorous monitoring (see table 64) and
shutdown procedures all of which make it unlikely that individuals
would be exposed to the exercise for extended periods or on consecutive
days, though some individuals may be exposed on multiple days.
Assessing the Number of Individuals Taken and the Likelihood of
Repeated Takes
As described previously, Navy modeling uses the best available
science to predict the instances of exposure above certain acoustic
thresholds, which are equated, as appropriate, to harassment takes. As
further noted, for

[[Page 20010]]

active acoustics it is more challenging to parse out the number of
individuals taken by Level B harassment and the number of times those
individuals are taken from this larger number of instances, though
factors such as movement ecology (e.g., is the species resident and
more likely to remain in closer proximity to ongoing activities, versus
nomadic or migratory; Keen et al. 2021) or whether there are known BIAs
where animals are known to congregate can help inform this. One method
that NMFS uses to help better understand the overall scope of the
impacts is to compare these total instances of take against the
abundance of that species (or stock if applicable). For example, if
there are 100 harassment takes in a population of 100, one can assume
either that every individual was exposed above acoustic thresholds once
per year, or that some smaller number were exposed a few times per
year, and a few were not exposed at all. Where the instances of take
exceed 100 percent of the population, multiple takes of some
individuals are predicted and expected to occur within a year.
Generally speaking, the higher the number of takes as compared to the
population abundance, the more multiple takes of individuals are
likely, and the higher the actual percentage of individuals in the
population that are likely taken at least once in a year. We look at
this comparative metric to give us a relative sense of where larger
portions of the species are being taken by the Action Proponents'
activities and where there is a higher likelihood that the same
individuals are being taken across multiple days and where that number
of days might be higher. It also provides a relative picture of the
scale of impacts to each species.
In the ocean, unlike a modeling simulation with static animals, the
transient nature of sonar use makes it unlikely to repeatedly expose
the same individual animals within a short period, for example, within
one specific exercise. However, some repeated exposures across
different activities could occur over the year with more resident
species. In short, we expect the total anticipated takes represent
exposures of a smaller number of individuals of which some could be
exposed multiple times, but based on the nature of the Action
Proponents' activities and the movement patterns of marine mammals, it
is unlikely that any particular subset would be taken over more than
several sequential days (with a few possible exceptions discussed in
the species-specific conclusions). In other cases, such as during
pierside sonar testing at Naval Station Norfolk, repeated exposures of
the same individuals may be more likely given the concentrated area
within which the operations occur and the likelihood that a smaller
number of animals would routinely use the affected habitat.
When calculating the proportion of a population taken (e.g., the
number of takes divided by population abundance), which can also be
helpful in estimating the number of days over which some individuals
may be taken, it is important to choose an appropriate population
estimate against which to make the comparison. Herein, NMFS considers
two potential abundance estimates, the SARs and the NMSDD abundance
estimates. The SARs, where available, provide the official population
estimate for a given species or stock in U.S. waters in a given year.
These estimates are typically generated from the most recent shipboard
and/or aerial surveys conducted, and in some cases, the estimates show
substantial year-to-year variability. When the stock is known to range
well outside of U.S. EEZ boundaries, population estimates based on
surveys conducted only within the U.S. EEZ are known to be
underestimates. The NMSDD-derived abundance estimates are abundances
for within the U.S. EEZ boundaries only and, therefore, differ from
some SAR abundance estimates.
The SAR and NMSDD abundance estimates can differ substantially
because these estimates may be based on different methods and data
sources. For example, the SARs only consider data from the past 8 year
period, whereas the NMSDD considers a longer data history. Further, the
SARs estimate the number of animals in a population but not spatial
densities. NMSDD uses predictive density models to estimate species
presence, even where sighting data is limited or lacking altogether.
Thus, NMSDD density models beyond the U.S. EEZ have greater uncertainty
than those within the U.S. EEZ, where most proposed activities would
occur. Each density model is limited to the variables and assumptions
considered by the original data source provider. NMFS considered these
factors and others described in the Density Technical Report (U.S.
Department of the Navy, 2024) when comparing the estimated takes to
current population abundances for each species or stock.
In consideration of the factors described above, to estimate
repeated impacts across large areas relative to species geographic
distributions, comparing the impacts predicted in NAEMO to abundances
predicted using the NMSDD models is usually preferable. By comparing
estimated take to the NMSDD abundance estimates, impacts and abundance
estimates are based on the same underlying assumptions about a species'
presence. NMFS has compared the estimated take to the NMSDD abundance
estimates herein for all stocks, with the exception of stocks where the
abundance information fits into one of the following scenarios, in
which case NMFS concluded that comparison to the SAR abundance estimate
is more appropriate: (1) a species' or stocks' range extends beyond the
U.S. EEZ and the SAR abundance estimate is greater than the NMSDD
abundance. For highly migratory species (e.g., large whales) or those
whose geographic distribution extends beyond the boundaries of the AFTT
Study Area (e.g., populations with distribution along the entire
western Atlantic Ocean rather than just the AFTT Study Area),
comparisons to the SAR are appropriate. Many of the stocks present in
the AFTT Study Area have ranges significantly larger than the AFTT
Study Area, and that abundance is captured by the SAR. A good
descriptive example is migrating large whales, which occur seasonally
in the AFTT Study Area. Therefore, at any one time there may be a
stable number of animals, but over the course of the entire year the
entire population may pass through the AFTT Study Area. Therefore,
comparing the estimated takes to an abundance, in this case the SAR
abundance, which represents the total population, may be more
appropriate than modeled abundances for only the AFTT Study Area; and
(2) when the current minimum population estimate in the SAR is greater
than the NMSDD abundance, regardless of whether the stock range extends
beyond the EEZ. The NMSDD and SAR abundance estimates are both included
in table 81 (mysticetes), table 83 (sperm whales, dwarf sperm whales,
and pygmy sperm whales), table 85 (beaked whales), table 87 (dolphins
and small whales), table 89 (porpoises), and table 91 (pinnipeds), and
each table indicates which stock abundance estimate was selected for
comparison to the take estimate for each species or stock.
Temporary Threshold Shift
NMFS and the Navy have estimated that all species of marine mammals
may incur some level of TTS from active sonar. As mentioned previously,
in general, TTS can last from a few minutes to days, be of varying
degree, and occur across various frequency bandwidths, all of which
determine the severity of the impacts on the affected individual, which
can range from minor

[[Page 20011]]

to more severe. Table 38 through table 46 indicate the number of takes
by TTS that may be incurred by different species from exposure to
active sonar, air guns, pile driving, and explosives. The TTS incurred
by an animal is primarily characterized by three characteristics:
(i) Frequency--Available data suggest that most TTS occurs in the
frequency range of the source up to one octave higher than the source
(with the maximum TTS at \1/2\ octave above) (Finneran 2015, Southall
et al. 2019). The Navy's MF anti-submarine warfare sources, which are
the highest power and most numerous sources and the ones that cause the
most take by TTS, utilize the 1-10 kHz frequency band, which suggests
that if TTS were to be induced by any of these MF sources it would be
in a frequency band somewhere between approximately 1 and 20 kHz, which
is in the range of communication calls for many odontocetes, but below
the range of the echolocation signals used for foraging. There are
fewer hours of HF source use and the sounds would attenuate more
quickly, plus they have lower source levels, but if an animal were to
incur TTS from these sources, it would cover a higher frequency range
(sources are between 10 and 100 kHz, which means that TTS could range
up to the highest frequencies audible to VHF cetaceans, approaching 200
kHz), which could overlap with the range in which some odontocetes
communicate or echolocate. However, HF systems are typically used less
frequently and for shorter time periods than surface ship and aircraft
MF systems, so TTS from HF sources is less likely than from MF sources.
There are fewer LF sources and the majority are used in the more
readily mitigated testing environment, and TTS from LF sources would
most likely occur below 2 kHz, which is in the range where many
mysticetes communicate and also where other auditory cues are located
(waves, snapping shrimp, fish prey). Also of note, the majority of
sonar sources from which TTS may be incurred occupy a narrow frequency
band, which means that the TTS incurred would also be across a narrower
band (i.e., not affecting the majority of an animal's hearing range).
(ii) Degree of the shift (i.e., by how many dB the sensitivity of
the hearing is reduced)--Generally, both the degree of TTS and the
duration of TTS will be greater if the marine mammal is exposed to a
higher level of energy (which would occur when the peak SPL is higher
or the duration is longer). The threshold for the onset of TTS was
discussed previously in this rule. An animal would have to approach
closer to the source or remain in the vicinity of the sound source
appreciably longer to increase the received SEL, which would be
difficult considering the Lookouts and the nominal speed of an active
sonar vessel (10-15 kn (18.5-27.8 km/hr)) and the relative motion
between the sonar vessel and the animal. In the TTS studies discussed
in the Potential Effects of Specified Activities on Marine Mammals and
Their Habitat section, some using exposures of almost an hour in
duration or up to 217 SEL, most of the TTS induced was 15 dB or less,
though Finneran et al. (2007) induced 43 dB of TTS with a 64-second
exposure to a 20 kHz source. The SQS-53 (MFAS) hull-mounted sonar (MF1)
nominally emits a short (1-second) ping typically every 50 seconds,
incurring those levels of TTS due to this source is highly unlikely.
Sources with higher duty cycles produce longer ranges to effects and
contribute to auditory effects from this action. Since any hull-mounted
sonar, such as the SQS-53, engaged in anti-submarine warfare training
would be moving at between 10 and 15 kn (18.5 to 27.8 km/hr) and
nominally pinging every 50 seconds, the vessel will have traveled a
minimum distance of approximately 843.2 ft (257 m) during the time
between those pings. For a Navy vessel moving at a nominal 10 kn (18.5
km/hr), it is unlikely a marine mammal would track with the ship and
could maintain speed parallel to the ship to receive adequate energy
over successive pings to suffer TTS. In short, given the anticipated
duration and levels of sound exposure, we would not expect marine
mammals to incur more than relatively low levels of TTS in most cases
for sonar exposure. To add context to this degree of TTS, individual
marine mammals may regularly experience variations of 6 dB differences
in hearing sensitivity in their lifetime (Finneran et al., 2000,
Finneran et al., 2002, Schlundt et al., 2000).
(iii) Duration of TTS (recovery time)--In the TTS laboratory
studies (as discussed in the Potential Effects of Specified Activities
on Marine Mammals and Their Habitat section), some using exposures of
almost an hour in duration or up to 217 dB SEL, almost all individuals
recovered within 1 day (or less, often in minutes), although in one
study (Finneran et al., 2015; Southall et al. 2019), recovery took 4
days.
Compared to laboratory studies, marine mammals are likely to
experience lower SELs from sonar used in the AFTT Study Area due to
movement of the source and animals, and because of the lower duty
cycles typical of higher power sources (though some of the Navy MF1C
sources have higher duty cycles). Therefore, TTS resulting from MFAS
would likely be of lesser magnitude and duration compared to laboratory
studies. Also, for the same reasons discussed in the Preliminary
Analysis and Negligible Impact Determination--Diel Cycle section, and
because of the short distance between the source and animals needed to
reach high SELs, it is unlikely that animals would be exposed to the
levels necessary to induce TTS in subsequent time periods such that
hearing recovery is impeded. Additionally, though the frequency range
of TTS that marine mammals might incur would overlap with some of the
frequency ranges of their vocalization types, the frequency range of
TTS from MFAS would not usually span the entire frequency range of one
vocalization type, much less span all types of vocalizations or other
critical auditory cues.
As a general point, the majority of the TTS takes are the result of
exposure to hull-mounted MFAS (MF narrower band sources), with fewer
from explosives (broad-band lower frequency sources), and even fewer
from LFAS or HFAS sources (narrower band). As described above, we
expect the majority of these takes to be in the form of mild, short-
term (minutes to hours), narrower band (only affecting a portion of the
animal's hearing range) TTS. This means that for one to several times
per year, for several minutes, maybe a few hours, or at most in limited
circumstances a few days, a taken individual will have diminished
hearing sensitivity (more than natural variation, but nowhere near
total deafness). More often than not, such an exposure would occur
within a narrower mid- to higher frequency band that may overlap part
(but not all) of a communication, echolocation, or predator range, but
sometimes across a lower or broader bandwidth. The significance of TTS
is also related to the auditory cues that are germane within the time
period that the animal incurs the TTS. For example, if an odontocete
has TTS at echolocation frequencies, but incurs it at night when it is
resting and not feeding, it is not impactful. In short, the expected
results of any one of these small number of mild TTS occurrences could
be that (1) it does not overlap signals that are pertinent to that
animal in the given time period, (2) it overlaps parts of signals that
are important to the animal, but not in a manner that impairs
interpretation, or (3) it reduces

[[Page 20012]]

detectability of an important signal to a small degree for a short
amount of time--in which case the animal may be aware and be able to
compensate (but there may be slight energetic cost), or the animal may
have some reduced opportunities (e.g., to detect prey) or reduced
capabilities to react with maximum effectiveness (e.g., to detect a
predator or navigate optimally). However, it is unlikely that
individuals would experience repeated or high degree TTS overlapping in
frequency and time with signals critical for behaviors that would
impact overall fitness.
Auditory Masking or Communication Impairment
The ultimate potential impacts of masking on an individual (if it
were to occur) are similar to those discussed for TTS, but an important
difference is that masking only occurs during the time of the signal,
versus TTS, which continues beyond the duration of the signal.
Fundamentally, masking is referred to as a chronic effect because one
of the key harmful components of masking is its duration--the fact that
an animal would have reduced ability to hear or interpret critical cues
becomes much more likely to cause a problem the longer it is occurring.
Also inherent in the concept of masking is the fact that the potential
for the effect is only present during the times that the animal and the
source are in close enough proximity for the effect to occur (and
further, this time period would need to coincide with a time that the
animal was utilizing sounds at the masked frequency). As our analysis
has indicated, because of the relative movement of vessels and the
sound sources primarily involved in this rule, we do not expect the
exposures with the potential for masking to be of a long duration.
Masking is fundamentally more of a concern at lower frequencies,
because low frequency signals propagate significantly farther than
higher frequencies and because they are more likely to overlap both the
narrower LF calls of mysticetes, as well as many non-communication cues
such as fish and invertebrate prey, and geologic sounds that inform
navigation. Masking is also more of a concern from continuous sources
(versus intermittent sonar signals) where there is no quiet time
between pulses and detection and interpretation of auditory signals is
likely more challenging. For these reasons, dense aggregations of, and
long exposure to, continuous LF activity are much more of a concern for
masking, whereas comparatively short-term exposure to the predominantly
intermittent pulses of often narrow frequency range MFAS or HFAS, or
explosions are not expected to result in a meaningful amount of
masking. While the Action Proponents occasionally use LF and more
continuous sources, it is not in the contemporaneous aggregate amounts
that would be expected to accrue to degrees that would have the
potential to affect reproductive success or survival. Additional detail
is provided below.
Standard hull-mounted MFAS typically pings every 50 seconds. Some
hull-mounted anti-submarine sonars can also be used in an object
detection mode known as ``Kingfisher'' mode (e.g., used on vessels when
transiting to and from port) where pulse length is shorter but pings
are much closer together in both time and space since the vessel goes
slower when operating in this mode, and during which an increased
likelihood of masking in the vicinity of vessel could be expected. For
the majority of other sources, however, the pulse length is
significantly shorter than hull-mounted active sonar, on the order of
several microseconds to tens of milliseconds. Some of the vocalizations
that many marine mammals make are less than 1 second long, so, for
example with hull-mounted sonar, there would be a 1 in 50 chance (only
if the source was in close enough proximity for the sound to exceed the
signal that is being detected) that a single vocalization might be
masked by a ping. However, when vocalizations (or series of
vocalizations) are longer than the 1 second pulse of hull-mounted
sonar, or when the pulses are only several microseconds long, the
majority of most animals' vocalizations would not be masked.
Most anti-submarine warfare sonars and countermeasures use MF
frequencies and a few use LF and HF frequencies. Most of these sonar
signals are limited in the temporal, frequency, and spatial domains.
The duration of most individual sounds is short, lasting up to a few
seconds each. A few systems operate with higher duty cycles or nearly
continuously, but they typically use lower power, which means that an
animal would have to be closer, or in the vicinity for a longer time,
to be masked to the same degree as by a higher level source.
Nevertheless, masking could occasionally occur at closer ranges to
these high-duty cycle and continuous active sonar systems, but as
described previously, it would be expected to be of a short duration.
While data are lacking on behavioral responses of marine mammals to
continuously active sonars, mysticete species are known to habituate to
novel and continuous sounds (Nowacek et al., 2004), suggesting that
they are likely to have similar responses to high-duty cycle sonars.
Furthermore, most of these systems are hull-mounted on surface ships
with the ships moving at least 10 kn (18.5 km/hr), and it is unlikely
that the ship and the marine mammal would continue to move in the same
direction and the marine mammal subjected to the same exposure due to
that movement. Most anti-submarine warfare activities are
geographically dispersed and last for only a few hours, often with
intermittent sonar use even within this period. Most anti-submarine
warfare sonars also have a narrow frequency band (typically less than
one-third octave). These factors reduce the likelihood of sources
causing significant masking. HF signals (above 10 kHz) attenuate more
rapidly in the water due to absorption than do lower frequency signals,
thus producing only a very small zone of potential masking. If masking
or communication impairment were to occur briefly, it would more likely
be in the frequency range of MFAS (the more powerful source), which
overlaps with some odontocete vocalizations (but few mysticete
vocalizations); however, it would likely not mask the entirety of any
particular vocalization, communication series, or other critical
auditory cue, because the signal length, frequency, and duty cycle of
the MFAS/HFAS signal does not perfectly resemble the characteristics of
any single marine mammal species' vocalizations.
Other sources used in the Action Proponents' training and testing
that are not explicitly addressed above, many of either higher
frequencies (meaning that the sounds generated attenuate even closer to
the source) or used less frequently, would be expected to contribute to
masking over far smaller areas and/or times. For the reasons described
here, any limited masking that could potentially occur would be minor
and short-term.
In conclusion, masking is more likely to occur in the presence of
broadband, relatively continuous noise sources such as from vessels,
however, the duration of temporal and spatial overlap with any
individual animal and the spatially separated sources that the Action
Proponents use would not be expected to result in more than short-term,
low impact masking that would not affect reproduction or survival.

[[Page 20013]]

Auditory Injury From Sonar Acoustic Sources and Explosives and Non-
Auditory Injury From Explosives
Table 38 through table 46 indicate the number of takes of each
species by Level A harassment in the form of auditory injury resulting
from exposure to active sonar and/or explosives is estimated to occur,
and table 50 indicates the totals across all activities. The number of
takes estimated to result from auditory injury annually from sonar, air
guns, and explosives for each species/stock from all activities
combined ranges from 0 to 180 (the 180 is for the Western North
Atlantic stock of dwarf sperm whale). Nineteen stocks (all odontocetes)
have the potential to incur non-auditory injury from explosives, and
the number of individuals from any given stock from all activities
combined ranges from 1 to 3 (the 3 is for the Northern Gulf of America
stock of pantropical spotted dolphin). As described previously, the
Navy's model likely overestimates the number of injurious takes to some
degree. Nonetheless, these Level A harassment take numbers represent
the maximum number of instances in which marine mammals would be
reasonably expected to incur auditory and/or non-auditory injury, and
we have analyzed them accordingly.
If a marine mammal is able to approach a surface vessel within the
distance necessary to incur auditory injury in spite of the mitigation
measures, the likely speed of the vessel (nominally 10-15 kn (18.5-27.8
km/hr)) and relative motion of the vessel would make it very difficult
for the animal to remain in range long enough to accumulate enough
energy to result in more than a mild case of auditory injury. As
discussed previously in relation to TTS, the likely consequences to the
health of an individual that incurs auditory injury can range from mild
to more serious, and is dependent upon the degree of auditory injury
and the frequency band associated with auditory injury. The majority of
any auditory injury incurred as a result of exposure to Navy sources
would be expected to be in the 2-20 kHz range (resulting from the most
powerful hull-mounted sonar) and could overlap a small portion of the
communication frequency range of many odontocetes, whereas other marine
mammal groups have communication calls at lower frequencies. Because of
the broadband nature of explosives, auditory injury incurred from
exposure to explosives would occur over a lower, but wider, frequency
range. Regardless of the frequency band, the more important point in
this case is that any auditory injury accrued as a result of exposure
to Navy activities would be expected to be of a small amount (single
digits). Permanent loss of some degree of hearing is a normal
occurrence for older animals, and many animals are able to compensate
for the shift, both in old age or at younger ages as the result of
stressor exposure. While a small loss of hearing sensitivity may
include some degree of energetic costs for compensating or may mean
some small loss of opportunities or detection capabilities, at the
expected scale it would be unlikely to impact behaviors, opportunities,
or detection capabilities to a degree that would interfere with
reproductive success or survival.
The Action Proponents implement mitigation measures (described in
the Proposed Mitigation Measures section) during explosive activities,
including delaying detonations when a marine mammal is observed in the
mitigation zone. Nearly all explosive events would occur during
daylight hours thereby improving the sightability of marine mammals and
mitigation effectiveness. Observing for marine mammals during the
explosive activities would include visual and passive acoustic
detection methods (the latter when they are available and part of the
activity) before the activity begins, in order to cover the mitigation
zones that can range from 200 yd (183 m) to 2,500 yd (2,286 m)
depending on the source (e.g., explosive sonobuoy, explosive torpedo,
explosive bombs), and 2.5 nmi (4.6 km) for sinking exercises (see table
55 through table 64).
The type and amount of take by Level A harassment are indicated for
all species and species groups in table 81, table 83, table 85, table
87, table 89, and table 91. Generally speaking, non-auditory injuries
from explosives could range from minor lung injuries (the most
sensitive organ and first to be affected) that consist of some short-
term reduction of health and fitness immediately following the injury
that heals quickly and will not have any discernible long-term effects,
up to more impactful permanent injuries across multiple organs that may
cause health problems and negatively impact reproductive success (i.e.,
increase the time between pregnancies or even render reproduction
unlikely) but fall just short of a ``serious injury'' by virtue of the
fact that the animal is not expected to die. Nonetheless, due to the
Navy's mitigation and detection capabilities, we would not expect
marine mammals to typically be exposed to a more severe blast located
closer to the source--so the impacts likely would be less severe. In
addition, most non-auditory injuries and mortalities or serious
injuries are predicted for stocks with medium to large group sizes,
mostly delphinids, which increases sightability. It is still difficult
to evaluate how these injuries may or may not impact an animal's
fitness, however, these effects are only seen in very small numbers
(single digits for all stocks) and mostly in species of moderate, high,
and very high abundances. In short, it is unlikely that any, much less
all, of the small number of injuries accrued to any one stock would
result in reduced reproductive success of any individuals; even if a
few injuries did result in reduced reproductive success of individuals,
the status of the affected stocks are such that it would not be
expected to adversely impact rates of reproduction (and auditory injury
of the low severity anticipated here is not expected to affect the
survival of any individual marine mammals).
Serious Injury and Mortality
NMFS is authorizing a very small number of serious injuries or
mortalities that could occur in the event of a vessel strike or as a
result of marine mammal exposure to explosive detonations (mostly
during ship shock trials). We note here that the takes from potential
vessel strikes or explosive exposures enumerated below could result in
non-serious injury, but their worst potential outcome (mortality) is
analyzed for the purposes of the negligible impact determination.
The MMPA requires that PBR be estimated in SARs and that it be used
in applications related to the management of take incidental to
commercial fisheries (i.e., the take reduction planning process
described in section 118 of the MMPA and the determination of whether a
stock is ``strategic'' as defined in section 3). While nothing in the
statute requires the application of PBR outside the management of
commercial fisheries interactions with marine mammals, NMFS recognizes
that as a quantitative metric, PBR may be useful as a consideration
when evaluating the impacts of other human-caused activities on marine
mammal stocks. Outside the commercial fishing context, and in
consideration of all known human-caused mortality, PBR can help inform
the potential effects of M/SI requested to be authorized under section
101(a)(5)(A). As noted by NMFS and the U.S. FWS in our implementing
regulations for the 1986 amendments to the MMPA (54 FR 40341, September
29, 1989), the Services consider many factors, when available, in
making a negligible impact determination,

[[Page 20014]]

including, but not limited to, the status of the species or stock
relative to OSP (if known); whether the recruitment rate for the
species or stock is increasing, decreasing, stable, or unknown; the
size and distribution of the population; and existing impacts and
environmental conditions. In this multi-factor analysis, PBR can be a
useful indicator for when, and to what extent, the agency should take
an especially close look at the circumstances associated with the
potential mortality, along with any other factors that could influence
annual rates of recruitment or survival.
Below we describe how PBR is considered in NMFS M/SI analysis.
Please see the 2020 Northwest Training and Testing Final Rule (85 FR
72312, November 12, 2020) for a background discussion of PBR and how it
was adopted for use authorizing incidental take under section
101(a)(5)(A) for specified activities such as the Action Proponent's
training and testing in the AFTT Study Area.
When considering PBR during evaluation of effects of M/SI under
section 101(a)(5)(A), we utilize a two-tiered analysis for each stock
for which M/SI is proposed for authorization:
(i) Tier 1: Compare the total human-caused average annual M/SI
estimate from all sources, including the M/SI proposed for
authorization from the specific activity, to PBR. If the total M/SI
estimate is less than or equal to PBR, then the specific activity is
considered to have a negligible impact on that stock. If the total M/SI
estimate (including from the specific activity) exceeds PBR, conduct
the Tier 2 analysis.
(ii) Tier 2: Evaluate the estimated M/SI from the specified
activity relative to the stock's PBR. If the M/SI from the specified
activity is less than or equal to 10 percent of PBR and other major
sources of human-caused mortality have mitigation in place, then the
individual specified activity is considered to have a negligible impact
on that stock. If the estimate exceeds 10 percent of PBR, then, absent
other mitigating factors, the specified activity is considered likely
to have a non-negligible impact on that stock.
Additional detail regarding the two tiers of the evaluation are
provided below.
As indicated above, the goal of the Tier 1 assessment is to
determine whether total annual human-caused mortality, including from
the specified activity, would exceed PBR. To aid in the Tier 1
evaluation and get a clearer picture of the amount of annual M/SI that
remains without exceeding PBR, for each species or stock, we first
calculate a ``residual PBR,'' which equals PBR minus the ongoing annual
human-caused M/SI (i.e., Residual PBR = PBR - (annual M/SI estimate
from the SAR + other M/SI authorized under 101(a)(5)(A)). If the
ongoing human-caused M/SI from other sources does not exceed PBR, then
residual PBR is a positive number, and we consider how the proposed
authorized incidental M/SI from the specified activities being
evaluated compares to residual PBR using the Tier 1 framework in the
following paragraph. If the ongoing anthropogenic mortality from other
sources already exceeds PBR, then residual PBR is a negative number and
we move to the Tier 2 discussion further below to consider the M/SI
from the specific activities.
To reiterate the Tier 1 analysis overview in the context of
residual PBR, if the M/SI from the specified activity does not exceed
PBR, the impacts of the authorized M/SI on the species or stock are
generally considered to be negligible. As a simplifying analytical tool
in the Tier 1 evaluation, we first consider whether the M/SI from the
specified activities could cause incidental M/SI that is less than 10
percent of residual PBR, which we consider an ``insignificance
threshold.'' If so, we consider M/SI from the specified activities to
represent an insignificant incremental increase in ongoing
anthropogenic M/SI for the marine mammal stock in question that alone
will clearly not adversely affect annual rates of recruitment and
survival and for which additional analysis or discussion of the
anticipated M/SI is not required because the negligible impact standard
clearly will not be exceeded on that basis alone.
When the M/SI from the specified activity is above the
insignificance threshold in the Tier 1 evaluation, it does not indicate
that the M/SI associated with the specified activities is necessarily
approaching a level that would exceed negligible impact. Rather, it is
used a cue to look more closely if and when the M/SI for the specified
activity approaches residual PBR, as it becomes increasingly necessary
(the closer the M/SI from the specified activity is to 100 percent
residual PBR) to carefully consider whether there are other factors
that could affect reproduction or survival, such as take by Level A
and/or Level B harassment that has been predicted to impact
reproduction or survival of individuals, or other considerations such
as information that illustrates high uncertainty involved in the
calculation of PBR for some stocks. Recognizing that the impacts of
harassment of any authorized incidental take (by Level A or Level B
harassment from the specified activities) would not combine with the
effects of the authorized M/SI to adversely affect the stock through
effects on recruitment or survival, if the proposed authorized M/SI for
the specified activity is less than residual PBR, the M/SI, alone,
would be considered to have a negligible impact on the species or
stock. If the proposed authorized M/SI is greater than residual PBR,
then the assessment should proceed to Tier 2.
For the Tier 2 evaluation, recognizing that the total annual human-
caused M/SI exceeds PBR, we consider whether the incremental effects of
the proposed authorized M/SI for the specified activity, specifically,
would be expected to result in a negligible impact on the affected
species or stocks. For the Tier 2 assessment, consideration of other
factors (positive or negative), including those described above (e.g.,
the certainty in the data underlying PBR and the impacts of any
harassment authorized for the specified activity), as well as the
mitigation in place to reduce M/SI from other activities is especially
important to assessing the impacts of the M/SI from the specified
activity on the species or stock. PBR is a conservative metric and not
sufficiently precise to serve as an absolute predictor of population
effects upon which mortality caps would appropriately be based. For
example, in some cases stock abundance (which is one of three key
inputs into the PBR calculation) is underestimated because marine
mammal survey data within the U.S. EEZ are used to calculate the
abundance even when the stock range extends well beyond the U.S. EEZ.
An underestimate of abundance could result in an underestimate of PBR.
Alternatively, we sometimes may not have complete M/SI data beyond the
U.S. EEZ to compare to PBR, which could result in an overestimate of
residual PBR. The accuracy and certainty around the data that feed any
PBR calculation, such as the abundance estimates, must be carefully
considered to evaluate whether the calculated PBR accurately reflects
the circumstances of the particular stock.
Also, as referenced above, in some cases the ongoing human-caused
mortality from activities other than those being evaluated already
exceeds PBR and, therefore, residual PBR is negative. In these cases,
any additional mortality, no matter how small, and no matter how small
relative to the mortality caused by other human activities, would
result in greater exceedance of PBR. PBR is helpful in

[[Page 20015]]

informing the analysis of the effects of mortality on a species or
stock because it is important from a biological perspective to be able
to consider how the total mortality in a given year may affect the
population. However, section 101(a)(5)(A) of the MMPA indicates that
NMFS shall authorize the requested incidental take from a specified
activity if we find that ``the total of such taking [i.e., from the
specified activity] will have a negligible impact on such species or
stock.'' In other words, the task under the statute is to evaluate the
applicant's anticipated take in relation to their take's impact on the
species or stock, not other entities' impacts on the species or stock.
Neither the MMPA nor NMFS' implementing regulations call for
consideration of other unrelated activities and their impacts on the
species or stock.
Accordingly, we may find that the impacts of the taking from the
specified activity may (alone) be negligible even when total human-
caused mortality from all activities exceeds PBR if (in the context of
a particular species or stock). Specifically, where the authorized M/SI
would be less than or equal to 10 percent of PBR and management
measures are being taken to address M/SI from the other contributing
activities (i.e., other than the specified activities covered by the
incidental take authorization under consideration), the impacts of the
authorized M/SI would be considered negligible. In addition, we must
also still determine that any impacts on the species or stock from
other types of take (i.e., harassment) caused by the applicant do not
combine with the impacts from mortality or serious injury addressed
here to result in adverse effects on the species or stock through
effects on annual rates of recruitment or survival.
As noted above, while PBR is useful in informing the evaluation of
the effects of M/SI in section 101(a)(5)(A) determinations, it is one
consideration to be assessed in combination with other factors and is
not determinative. For example, as explained above, the accuracy and
certainty of the data used to calculate PBR for the species or stock
must be considered. And we reiterate the considerations discussed above
for why it is not appropriate to consider PBR an absolute cap in the
application of this guidance. Accordingly, we use PBR as a trigger for
concern while also considering other relevant factors to provide a
reasonable and appropriate means of evaluating the effects of potential
mortality on rates of recruitment and survival, while acknowledging
that it is possible for total human-caused M/SI to exceed PBR (or for
the M/SI from the specified activity to exceed 10 percent of PBR in the
case where other human-caused mortality is exceeding PBR, as described
in the last paragraph) by some small amount and still make a negligible
impact determination under section 101(a)(5)(A).
We note that on June 17, 2020, NMFS finalized new Criteria for
Determining Negligible Impact under MMPA section 101(a)(5)(E). The
guidance explicitly notes the differences in the negligible impact
determinations required under section 101(a)(5)(E), as compared to
sections 101(a)(5)(A) and 101(a)(5)(D), and specifies that the
procedure in that document is limited to how the agency conducts
negligible impact analyses for commercial fisheries under section
101(a)(5)(E). In this proposed rule, NMFS has described its method for
considering PBR to evaluate the effects of potential mortality in the
negligible impact analysis. NMFS has reviewed the 2020 guidance and
determined that our consideration of PBR in the evaluation of mortality
as described above and in the proposed rule remains appropriate for use
in the negligible impact analysis for the Action proponent's activities
under section 101(a)(5)(A).
Our evaluation of the M/SI for each of the species and stocks for
which mortality or serious injury could occur follows.
We first consider maximum potential incidental M/SI from the Action
Proponents' vessel strike analysis for the affected large whales (table
79) and from the Action Proponents' explosive detonations for the
affected small cetaceans (table 80) in consideration of NMFS' threshold
for identifying insignificant M/SI take. By considering the maximum
potential incidental M/SI in relation to PBR and ongoing sources of
anthropogenic mortality, as described above, we begin our evaluation of
whether the potential incremental addition of M/SI through vessel
strikes and explosive detonations may affect the species' or stocks'
annual rates of recruitment or survival. We also consider the
interaction of those mortalities with incidental taking of that species
or stock by harassment pursuant to the specified activity.
Based on the methods discussed previously, NMFS is proposing to
authorize six mortalities of large whales due to vessel strike over the
course of the 7-year rule, three by each Action Proponent. Across the
7-year duration of the rule, two takes by mortality (annual average of
0.29 takes) of fin whale (Western North Atlantic stock), minke whale
(Canadian East Coast stock), sei whale (Nova Scotia stock), and sperm
whale (North Atlantic stock) could occur and are proposed for
authorization table 79); one take by mortality (annual average of 0.14
takes) of the Northern Gulf of America stock of sperm whale could occur
and is proposed for authorization; four takes by mortality (annual
average of 0.57 takes) of humpback whale (Gulf of Maine stock) could
occur and are proposed for authorization (table 79). To calculate the
annual average of M/SI by vessel strike, we divided the 7-year proposed
take by serious injury or mortality by seven.

[[Page 20016]]

Table 79--Summary Information Related to Mortalities Requested for Vessel Strike
[2025-2032]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Annual 7-Year
proposed proposed
Fisheries NEFSC Residual take by take by
Total interactions (Y/N); Annual M/ authorized PBR (PBR Recent UME (Y/N); serious serious
Common name Stock Stock annual annual rate of M/SI SI due to take PBR minus number of injury or injury or
abundance M/SI from fisheries vessel (annual) annual M/ strandings, year mortality mortality
\a\ interactions collision \b\ SI) \c\ declared (all action (all action
proponents)
\d\ proponents)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Fin Whale......................... Western North 6,802 2.05 Y; 1.45 0.6 0 11 8.95 N 0.29 2
Atlantic.
Humpback Whale.................... Gulf of Maine....... 1,396 12.15 Y; 7.75 4.4 0 22 9.85 Y; 244, 2017 0.57 4
Minke Whale....................... Canadian Eastern 21,968 9.40 Y; 8.6 0.8 1 170 159.6 Y; 198, 2018 0.29 2
Coastal.
Sei Whale......................... Nova Scotia......... 6,292 0.60 Y; 0.4 0 0 6.2 5.6 N 0.29 2
Sperm Whale....................... North Atlantic...... 5,895 0.20 N 0 0 9.28 9.08 N 0.29 2
Sperm Whale *..................... Northern Gulf of 1,614 9.60 Y; 0.2 0 0 2 -7.6 N 0.14 \e\ 1
America.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Unk = Unknown; N/A = Not Applicable.
* Stock abundance from NMSDD (see table 2.4-1 in appendix A of the application).
\a\ This column represents the total number of incidents of M/SI that could potentially accrue to the specified species or stock.
\b\ This column represents the annual authorized take by mortality in the 2021 LOA for Northeast Fisheries Science Center Fisheries Research Activities. No take of large whales was authorized
in the 2020 LOA for Southeast Fisheries Science Center Fisheries Research Activities.
\c\ This value represents the calculated PBR less the average annual estimate of ongoing anthropogenic mortalities (i.e., total annual human-caused M/SI, which is presented in the SARs).
\d\ This column represents the annual take by serious injury or mortality during Navy training and testing activities and was calculated by the number of mortalities proposed for authorization
divided by 7 years.
\e\ Authorized for U.S. Navy only.

[[Page 20017]]

The Action Proponents also requested a small number of takes by M/
SI from explosives. Across the 7-year duration of the rule, NMFS is
proposing to authorize five takes by M/SI (annual average of 0.71
takes) of pantropical spotted dolphin (Northern Gulf of America stock),
two takes by M/SI (annual average of 0.29 takes) of striped dolphin
(Northern Gulf of America stock), two takes by M/SI (annual average of
0.29 takes) of bottlenose dolphin (Western North Atlantic Offshore
stock), one take by M/SI (annual average of 0.14 takes) of Tamanend's
bottlenose dolphin (Western North Atlantic South Carolina/Georgia
Coastal), and three takes by M/SI (annual average of 0.43 takes) of
Clymene dolphin (Western North Atlantic stock) (table 80). To calculate
the annual average of M/SI from explosives, we divided the 7-year
proposed take by serious injury or mortality by seven (table 80), the
same method described for vessel strikes.

[[Page 20018]]

Table 80--Summary Information Related to AFTT Serious Injury or Mortality From Explosives
[2025-2032]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Annual 7-Year
proposed proposed
Fisheries SEFSC NEFSC Residual Recent UME take by take by
Total interactions (Y/ authorized authorized PBR (PBR (Y/N); serious serious
Species Stock Stock annual N); annual rate take take PBR minus number of injury or injury or Population trend
abundance M/SI \a\ of M/SI from (annual) (annual) annual M/ strandings, mortality mortality
fisheries \b\ \b\ SI) \c\ year declared (all action (all action
interactions proponents)
\d\ proponents)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Pantropical spotted dolphin... Northern Gulf of 37,195 241 N 0.8 0 304 62.2 N 0.71 5 Potentially
America. increasing.
Striped dolphin *............. Northern Gulf of 7,782 13 N 0.6 0 12 -1.6 N 0.29 2 Unk.
America.
Bottlenose dolphin *.......... Western North 150,704 28 Y; 28 0.8 1.6 507 476.6 N 0.29 2 Stable,
Atlantic potentially
Offshore. decreasing.
Tamanend's bottlenose dolphin. Western North 9,121 0.2-0.6 Y; 0.2-0.6 0.6 0 73 71.8 N 0.14 1 Unk
Atlantic, South/ (insufficient
Carolina Georgia data).
Coastal.
Clymene dolphin............... Western North 21,778 0 N 0 0 126 126 N 0.43 3 Unk.
Atlantic.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Unk = Unknown, SEFSC = Southeast Fisheries Science Center, NEFSC = Northeast Fisheries Science Center.
* Stock abundance from NMSDD (see table 2.4-1 in appendix A of the application).
\a\ This column represents the total number of incidents of M/SI that could potentially accrue to the specified species or stock.
\b\ These columns represents the annual authorized take by mortality in the 2020 LOA for Southeast Fisheries Science Center Fisheries Research Activities and the 2021 LOA for Northeast
Fisheries Science Center Fisheries Research Activities.
\c\ This value represents the calculated PBR less the average annual estimate of ongoing anthropogenic mortalities (i.e., total annual human-caused M/SI, which is presented in the SARs).
\d\ This column represents the annual take by serious injury or mortality during training and testing activities and was calculated by the number of mortalities proposed for authorization
divided by 7 years.

[[Page 20019]]

Stocks With M/SI From the Specified Activity Below the Insignificance
Threshold--
As noted above, for a species or stock with M/SI proposed for
authorization less than 10 percent of residual PBR, we consider M/SI
from the specified activities to represent an insignificant incremental
increase in ongoing anthropogenic M/SI that alone (i.e., in the absence
of any other take and barring any other unusual circumstances) will
clearly not adversely affect annual rates of recruitment and survival.
In this case, as shown in table 79 and table 80, the following species
or stocks have potential or estimated take by M/SI from vessel strike
and explosives, respectively, and proposed for authorization below
their insignificance threshold: fin whale (Western North Atlantic
stock), humpback whale (Gulf of Maine stock), minke whale (Canadian
East Coast stock), sei whale (Nova Scotia stock), sperm whale (North
Atlantic stock), pantropical spotted dolphin (Northern Gulf of America
Stock), bottlenose dolphin (Western North Atlantic Offshore),
Tamanend's bottlenose dolphin (Western North Atlantic South Carolina/
Georgia Coastal Stock), Clymene dolphin (Western North Atlantic Stock).
While the authorized M/SI of humpback whales (Gulf of Maine stock) and
minke whales (Canadian East Coast stock) are each below the
insignificance threshold, because of the current UMEs, we further
address how the authorized M/SI and the UMEs inform the negligible
impact determinations immediately below. For the other seven stocks
with authorized M/SI below the insignificance threshold, there are no
other known factors, information, or unusual circumstances that
indicate anticipated M/SI below the insignificance threshold could have
adverse effects on annual rates of recruitment or survival and they are
not discussed further. For the remaining stocks with potential M/SI
above the insignificance threshold, how that M/SI compares to residual
PBR, as well as additional factors, are discussed below as well.
Humpback Whale (Gulf of Maine Stock)
For this stock, PBR is currently set at 22. The total annual M/SI
from other sources of anthropogenic mortality is estimated to be 12.15.
This yields a residual PBR of 9.85. The additional 0.57 annual
mortalities that are authorized in this rule are below the
insignificance threshold (10 percent of residual PBR, in this case
0.985). Nonetheless, since January 2016, elevated humpback whale
mortalities have occurred along the Atlantic coast from Maine to
Florida. As of February 6, 2025, there have been 244 known strandings,
and of the whales examined, about 40 percent had evidence of human
interaction either from vessel strike or entanglement. NOAA is
consulting with researchers that are conducting studies on the humpback
whale populations, and these efforts may provide information on changes
in whale distribution and habitat use that could provide additional
insight into how these vessel interactions occurred. However, even in
consideration of the UME, the incremental increase in annual mortality
from the Action Proponents' specified activities is not expected to
adversely affect annual rates of recruitment or survival.
Minke Whale (Canadian East Coast Stock)
For this stock, PBR is currently set at 170. The total annual M/SI
from other sources of anthropogenic mortality is estimated to be 9.4.
In addition, 1 annual mortality has been authorized for this same stock
in the current incidental take regulations for NMFS' Northeast
Fisheries Science Center (86 FR 58434, October 21, 2021). This yields a
residual PBR of 159.6. The additional 0.29 annual mortalities that are
authorized in this rule are well below the insignificance threshold (10
percent of residual PBR, in this case 16.0). Nonetheless, minke whale
mortalities detected along the Atlantic coast from Maine through South
Carolina resulted in the declaration of an on-going UME in 2017.
Preliminary findings show evidence of human interactions or infectious
disease, but these findings are not consistent across all of the minke
whales examined, so more research is needed. As of February 10, 2025, a
total of 198 minke whales have stranded during this UME, averaging
about 25 animals per year. However, even in consideration of the UME,
the incremental increase in annual mortality from the Action
Proponents' activities is not expected to adversely affect annual rates
of recruitment or survival.
Stocks With M/SI From the Specified Activity Above the Insignificance
Threshold (and, in This Case, Also Above Residual PBR)--
Sperm Whale (Northern Gulf of America Stock)
For the Northern Gulf of America stock of sperm whale, PBR is
currently set at 2 and the total annual M/SI is estimated at 9.6,
yielding a residual PBR of -7.6. NMFS is proposing to authorize one M/
SI (U.S. Navy only) over the 7-year duration of the rule (indicated as
0.14 annually for the purposes of comparing to PBR and evaluating
overall effects on annual rates of recruitment and survival), which
means that residual PBR is exceeded by 7.74. However, as described
above, given that the negligible impact determination is based on the
assessment of take of the activity being analyzed, when total annual
mortality from human activities is higher, but the impacts from the
specific activity being analyzed are very small, NMFS may still find
the impact of the authorized take from a specified activity to be
negligible even if total human-caused mortality exceeds PBR--
specifically if the authorized mortality is less than 10 percent of PBR
and management measures are being taken to address serious injuries and
mortalities from the other activities causing mortality (i.e., other
than the specified activities covered by the incidental take
authorization in consideration). When those considerations are applied
here, the authorized lethal take (0.14 annually) of Northern Gulf of
America stock of sperm whale is less than 10 percent of PBR (PBR is 2).
Additionally, there are management measures in place to address M/SI
from activities other than those the Action Proponents are conducting
(as discussed below). Immediately below, we explain the information
that supports our finding that the M/SI proposed for authorization
herein is not expected to result in more than a negligible impact on
this stock. As described previously, NMFS must also ensure that impacts
by the applicant on the species or stock from other types of take
(i.e., harassment) do not combine with the impacts from mortality to
adversely affect the species or stock via impacts on annual rates of
recruitment or survival, which we have done further below in the stock-
specific conclusion sections.
As discussed, we also take into consideration management measures
in place to address M/SI caused by other activities. As reported in the
SAR, of the total annual M/SI of this stock (9.6), 9.4 of those M/SI
are from the DWH oil spill. (The remaining 0.2 are fishery-related M/
SI.) Since the DWH spill, there have been numerous recovery efforts for
marine mammals. The DWH oil spill NRDA settlement allocated
$144,000,000 to marine mammal restoration, and as of 2021, $30,968,016
has been allocated (DWH NRDA Trustees, 2021). Projects have focused

[[Page 20020]]

on understanding and assessing Gulf cetacean populations, enhancing the
capacity of stranding and response programs, enhancing our
understanding of, and reducing, stressors on cetaceans, and developing
and implementing decision support tools for cetaceans. Recovery efforts
have included some efforts to minimize impacts to marine mammals from
ocean noise. Proposals and planning for additional pilot projects,
including projects to test existing alternatives to traditional airgun
seismic surveys, engineering solutions for vessel quieting, and
operational approaches for quieting commercial vessels while underway
(Southall et al. 2024).
In this case, 0.14 M/SI means one mortality in 1 of the 7 years and
zero mortalities in 6 of those 7 years. Therefore, the Action
Proponents would not be contributing to the total human-caused
mortality at all in 6 of the 7, or 85.7 percent, of the years covered
by this rulemaking. That means that even if a Northern Gulf of America
stock of sperm whale were to be taken by mortality from vessel strike,
in 6 of the 7 years there could be no effect on annual rates of
recruitment or survival from Action Proponent-caused M/SI.
Additionally, the loss of a male would have far less, if any, effect on
population rates and absent any information suggesting that one sex is
more likely to be struck than another, we can reasonably assume that
there is a 50 percent chance that the single strike authorized by this
rulemaking would be a male, thereby further decreasing the likelihood
of impacts on the population rate. In situations like this where
potential M/SI is fractional, consideration must be given to the
lessened impacts anticipated due to the absence of M/SI in 6 of the 7
years and the fact that the single strike could be a male. Lastly, we
reiterate that PBR is a conservative metric and also not sufficiently
precise to serve as an absolute predictor of population effects upon
which mortality caps would appropriately be based. This is especially
important given the minor difference between zero and one across the 7-
year period covered by this rulemaking, which is the smallest
distinction possible when considering mortality. As noted above, Wade
et al. (1998) (authors of the paper from which the current PBR equation
is derived) note, ``Estimating incidental mortality in 1 year to be
greater than the PBR calculated from a single abundance survey does not
prove the mortality will lead to depletion; it identifies a population
worthy of careful future monitoring and possibly indicates that
mortality-mitigation efforts should be initiated.'' Importantly, M/SI
proposed for authorization is below 10 percent of PBR, and management
actions are in place to support recovery of the stock following the DWH
oil spill impacts. Based on the presence of the factors described
above, we do not expect lethal take from Navy activities, alone, to
adversely affect Northern Gulf of America stock of sperm whales through
effects on annual rates of recruitment or survival. Nonetheless, the
fact that total human-caused mortality exceeds PBR necessitates close
attention to the remainder of the impacts (i.e., harassment) on the
Northern Gulf of America stock of sperm whale from the Action
Proponents' activities to ensure that the total authorized takes have a
negligible impact on the species or stock. Therefore, this information
will be considered in combination with our assessment of the impacts of
authorized harassment takes in the Group and Species-Specific Analyses
section that follows.
Striped Dolphin (Northern Gulf of America Stock)
For striped dolphin (Northern Gulf of America stock), PBR is
currently set at 12 and the total annual M/SI is estimated at greater
than or equal to 13. As described in the SAR, these 13 M/SI are
predicted M/SI from the DWH oil spill. In addition, 0.6 annual
mortalities have been authorized for this same stock in the current
incidental take regulations for NMFS' Southeast Fisheries Science
Center (85 FR 27028, May 6, 2020). This yields a residual PBR of -1.6.
NMFS is proposing to authorize two M/SI for the Navy over the 7-year
duration of the rule (indicated as 0.29 annually for the purposes of
comparing to PBR and evaluating overall effects on annual rates of
recruitment and survival), which means that residual PBR is exceeded by
1.74. However, as described above, given that the negligible impact
determination is based on the assessment of take of the activity being
analyzed, when total annual mortality from human activities is higher,
but the impacts from the specific activity being analyzed are very
small, NMFS may still find the impact of the authorized take from a
specified activity to be negligible even if total human-caused
mortality exceeds PBR--specifically if the authorized mortality is less
than 10 percent of PBR and management measures are being taken to
address serious injuries and mortalities from the other activities
causing mortality (i.e., other than the specified activities covered by
the incidental take authorization in consideration). When those
considerations are applied here, the authorized lethal take (0.29
annually) of Northern Gulf of America stock of striped dolphin is less
than 10 percent of PBR (PBR is 12). Additionally, there are management
measures in place to address M/SI from activities other than those the
Action Proponents are conducting (as discussed below). Immediately
below, we explain the information that supports our finding that the M/
SI proposed for authorization herein is not expected to result in more
than a negligible impact on this stock. As described previously, NMFS
must also ensure that impacts by the applicant on the species or stock
from other types of take (i.e., harassment) do not combine with the
impacts from mortality to adversely affect the species or stock via
impacts on annual rates of recruitment or survival, which we have done
further below in the stock-specific conclusion sections.
As discussed, we also take into consideration management measures
in place to address M/SI caused by other activities. As reported in the
SAR, all 13 of the total annual M/SI of this stock are from the DWH oil
spill. As described in the previous section in more detail, since the
DWH spill, there have been numerous recovery efforts for marine
mammals, including some efforts to minimize impacts to marine mammals
from ocean noise, such as pilot projects to test existing alternatives
to traditional airgun seismic surveys, engineering solutions for vessel
quieting, and operational approaches for quieting commercial vessels
while underway (Southall et al. 2024).
Additionally of note, in this case, 0.29 M/SI means one mortality
in 1 of the 7 years and zero mortalities in 6 of those 7 years.
Therefore, the Action Proponents would not be contributing to the total
human-caused mortality at all in 6 of the 7, or 85.7 percent, of the
years covered by this rulemaking. That means that even if a striped
dolphin were to be taken by mortality from explosives, in 6 of the 7
years there could be no effect on annual rates of recruitment or
survival from Action Proponent-caused M/SI. Additionally, the loss of a
male would have far less, if any, effect on population rates and absent
any information suggesting that one sex is more likely to be injured
than another, we can reasonably assume that there is a 50 percent
chance that the two mortalities authorized by this rulemaking would be
a male, thereby further decreasing the likelihood of impacts on the
population rate. In

[[Page 20021]]

situations like this where potential M/SI is fractional, consideration
must be given to the lessened impacts anticipated due to the absence of
M/SI in 6 of the 7 years and the fact that the single strike could be a
male. Lastly, we reiterate that PBR is a conservative metric and also
not sufficiently precise to serve as an absolute predictor of
population effects upon which mortality caps would appropriately be
based. This is especially important given the minor difference between
zero and one across the 7-year period covered by this rulemaking, which
is the smallest distinction possible when considering mortality. As
noted previously, Wade et al. (1998) state, ``Estimating incidental
mortality in 1 year to be greater than the PBR calculated from a single
abundance survey does not prove the mortality will lead to depletion;
it identifies a population worthy of careful future monitoring and
possibly indicates that mortality-mitigation efforts should be
initiated.'' Further, M/SI proposed for authorization is below 10
percent of PBR, and management actions are in place to support recovery
of the stock following the DWH oil spill impacts. Based on the presence
of the factors described above, we do not expect lethal take from Navy
activities, alone, to adversely affect Northern Gulf of America stock
of striped dolphins through effects on annual rates of recruitment or
survival. Nonetheless, the fact that total human-caused mortality
exceeds PBR necessitates close attention to the remainder of the
impacts (i.e., harassment) on the Northern Gulf of America stock of
striped dolphins from the Action Proponents' activities to ensure that
the total authorized takes have a negligible impact on the species or
stock. Therefore, this information will be considered in combination
with our assessment of the impacts of authorized harassment takes in
the Group and Species-Specific Analyses section that follows.

Deepwater Horizon Oil Spill

As discussed in the earlier Deepwater Horizon Oil Spill section,
the DWH oil spill caused a suite of adverse health effects to marine
mammals in the GOM. Coastal and estuarine bottlenose dolphin
populations were some of the most severely injured (Hohn et al., 2017;
Rosel et al., 2017; Thomas et al., 2017), but oceanic species were also
exposed and experienced increased mortality, increased reproductive
failure, and a higher likelihood of other adverse health effects.
Due to the scope of the spill, the magnitude of potentially injured
populations, and the difficulties and limitations of working with
marine mammals, it is impossible to quantify injury without
uncertainty. Wherever possible, the quantification results represent
ranges of values that encapsulate the uncertainty inherent in the
underlying datasets. The population model outputs shown in table 15
best represent the temporal magnitude of the injury and the potential
recovery time from the injury (DWH NRDA Trustees, 2016). The values in
the table inform the baseline levels of both individual health and
susceptibility to additional stressors, as well as stock status, with
which the effects of the Action Proponents' takes are considered in the
negligible impact analysis. Additionally, estimates of annual mortality
for many stocks now include mortality attributed to the effects of the
DWH oil spill (see table 15) (Hayes et al., 2024), and these mortality
estimates are considered as part of the environmental baseline.

Group and Species-Specific Analyses

In this section, we build on the general analysis that applies to
all marine mammals in the AFTT Study Area from the previous sections.
We first include information and analysis that applies to mysticetes
or, separately, odontocetes, or pinnipeds, and then within those three
sections, more specific information that applies to smaller groups,
where applicable, and the affected species or stocks. The specific
authorized take numbers are also included in the analyses below, and so
here we provide some additional context and discussion regarding how we
consider the authorized take numbers in those analyses.
The maximum amount and type of incidental take of marine mammals
reasonably likely to occur and therefore proposed to be authorized from
exposures to sonar and other active acoustic sources and explosions
during the 7-year activity period are shown in table 35, table 36, and
table 37, and the subset attributable to ship shock trials is included
in table 45.
In the discussions below, the estimated takes by Level B harassment
represent instances of take, not the number of individuals taken (the
much lower and less frequent Level A harassment takes are far more
likely to be associated with separate individuals), and in some cases
individuals may be taken more than one time. As part of our evaluation
of the magnitude and severity of impacts to marine mammal individuals
and the species, and specifically in an effort to better understand the
degree to which the modeled and estimated takes likely represent
repeated takes of the individuals of a given species/stock, we consider
the total annual numbers of take by harassment (auditory injury, non-
auditory injury, TTS, and behavioral disturbance) for species or stocks
as compared to their associated abundance estimates--specifically, take
numbers higher than the stock abundance clearly indicate that some
number of individuals are being taken on more than one day in the year,
and broadly higher or lower ratios of take to abundance may reasonably
be considered to equate to higher or lower likelihood of repeated
takes, respectively, other potentially influencing factors being equal.
In addition to the mathematical consideration of estimated take
compared to abundance, we also consider other factors or circumstances
that may influence the likelihood of repeated takes, where known, such
as circumstances where activities resulting in take are focused in an
area and time (e.g., instrumented ranges or a homeport, or long-
duration activities such as manor training exercises) and/or where the
same individual marine mammals are known to congregate over longer
periods of time (e.g., pinnipeds at a haulout, mysticetes in a known
foraging area, or resident odontocetes with smaller home ranges).
Similarly, and all else being equal, estimated takes that are largely
focused in one region and/or season (see table 81, table 83, table 85,
table 87, table 89, and table 91) may indicate a higher likelihood of
repeated takes of the same individuals.
Occasional, milder behavioral responses are unlikely to cause long-
term consequences for individual animals or populations, and even if
some smaller subset of the takes are in the form of a longer (several
hours or a day) and more severe response, if they are not expected to
be repeated over a comparatively longer duration of sequential days,
impacts to individual fitness are not anticipated. Nearly all studies
and experts agree that infrequent exposures of a single day or less are
unlikely to impact an individual's overall energy budget (Farmer et
al., 2018; Harris et al., 2017; King et al., 2015; NAS 2017; New et
al., 2014; Southall et al., 2007; Villegas-Amtmann et al., 2015;
Hoekendijk et al., 2018; Wisniewska et al., 2018; Czapanskiy et al.,
2021; Pirotta, 2022). Generally speaking, and in the case of most
species impacted by the proposed activities, in the cases where some
number of individuals may reasonably be expected to be taken on more
than one day within a year, that number of

[[Page 20022]]

days would be comparatively small and also with no reason to expect
that those takes would occur on sequential days. In the rarer cases of
species where individuals might be expected to be taken on a
comparatively higher number of days of the year and there are reasons
to think that these days might be sequential or clumped together, the
likely impacts of this situation are discussed explicitly in the
species discussions.
To assist in understanding what this analysis means, we clarify a
few issues related to estimated takes and the analysis here. An
individual that incurs AUD INJ or TTS may sometimes, for example, also
be subject to behavioral disturbance at the same time. As described
above in this section, the degree of auditory injury, and the degree
and duration of TTS, expected to be incurred from the Navy's activities
are not expected to impact marine mammals such that their reproduction
or survival could be affected. Similarly, data do not suggest that a
single instance in which an animal accrues auditory injury or TTS and
is also subjected to behavioral disturbance would result in impacts to
reproduction or survival. Alternately, we recognize that if an
individual is subjected to behavioral disturbance repeatedly for a
longer duration and on consecutive days, effects could accrue to the
point that reproductive success is impacted. Accordingly, in analyzing
the number of takes and the likelihood of repeated and sequential
takes, we consider the total takes, not just the takes by Level B
harassment by behavioral disturbance, so that individuals potentially
exposed to both threshold shift and behavioral disturbance are
appropriately considered. The number of takes by Level A harassment by
auditory injury are so low (and zero in some cases) compared to
abundance numbers that it is considered highly unlikely that any
individual would be taken at those levels more than once.
Use of sonar and other transducers would typically be transient and
temporary. The majority of acoustic effects to most marine mammal
stocks from sonar and other active sound sources during the specified
military readiness activities would be primarily from anti-submarine
warfare events. On the less severe end, exposure to comparatively lower
levels of sound at a detectably greater distance from the animal, for a
few or several minutes, could result in a behavioral response such as
avoiding an area that an animal would otherwise have moved through or
fed in, or breaking off one or a few feeding bouts. More severe
behavioral effects could occur when an animal gets close enough to the
source to receive a comparatively higher level of sound, is exposed
continuously to one source for a longer time, or is exposed
intermittently to different sources throughout a day. Such effects
might result in an animal having a more severe flight response and
leaving a larger area for a day or more, or potentially losing feeding
opportunities for a day. However, such severe behavioral effects are
expected to occur infrequently. In addition to the proximity to the
source, the type of activity and the season and location during which
an animal is exposed, can inform the impacts. These factors, including
the numbers and types of effects that are estimated in areas known to
be biologically important for certain species are discussed in the
group and species-specific sections, below.
Further, as described in the Proposed Mitigation Measures section,
this proposed rule includes mitigation measures that would reduce the
probability and/or severity of impacts expected to result from acute
exposure to acoustic sources or explosives, vessel strike, and impacts
to marine mammal habitat. Specifically, the Action Proponents would use
a combination of delayed starts, powerdowns, and shutdowns to avoid
mortality or serious injury, minimize the likelihood or severity of AUD
INJ or non-auditory injury, and reduce instances of TTS or more severe
behavioral disturbance caused by acoustic sources or explosives. The
Action Proponents would also implement multiple time/area restrictions
that would reduce take of marine mammals in areas or at times where
they are known to engage in important behaviors, such as calving, where
the disruption of those behaviors would have a higher probability of
resulting in impacts on reproduction or survival of individuals that
could lead to population-level impacts.
These time/area restrictions include ship shock trial mitigation
areas throughout the Study Area, MTE Planning Awareness Mitigation
Areas in the Northeast and Mid-Atlantic, a Gulf of Maine Marine Mammal
Mitigation Area, several mitigation areas specific to NARW, and a
Rice's Whale Mitigation Area. Mitigation areas for NARW and Rice's
whale specifically are discussed in those species-specific sections
below. However, it is important to note that measures in those areas,
while developed to protect those species, would also benefit other
marine mammals in those areas. Therefore, they are discussed here also.
Regarding ship shock trials, the Action Proponents will not conduct
ship shock trials within the Rice's whale core distribution area in the
northern Gulf of America or within the portion of the ship shock trial
box that overlaps the Jacksonville OPAREA from November 15 through
April 15. These mitigation measures would avoid potential exposure of
Rice's whales to injurious levels of sound and avoid potential
injurious and behavioral impacts to NARW during calving season.
Additionally, pre-event planning for ship shock trials will include the
selection of sites where marine mammal abundance is expected to be the
lowest during the planned event and prioritize sites more than 2 nmi
(3.7 km) from the western boundary of the Gulf Stream where marine
mammals would be expected in greater concentrations for foraging and
migration. Overall, the benefits of Ship Shock Trial Mitigation Areas
would be substantial for all marine mammal taxa because ship shock
trials use the largest NEW of any explosive activity conducted in the
AFTT Study Area.
Regarding MTEs, the Action Proponents will not conduct any MTEs or
any portion of any MTE in the Major Training Exercise Planning
Awareness Mitigation Areas in the northeast. This would restrict MTEs
from occurring within NARW foraging critical habitat, on Georges Bank,
and in areas that contain underwater canyons (e.g., Hydrographer
Canyon, and a portion of the Northeast Canyons and Seamounts National
Marine Monument), as these locations have been associated with high
marine mammal abundance, feeding, and mating. In the Major Training
Exercise Planning Awareness Mitigation Areas in the mid-Atlantic, the
Action Proponents will not conduct any MTEs or any portion of any MTE
to the maximum extent practicable, and would conduct no more than four
(or a portion of more than four) MTEs per year. This would restrict the
number of MTEs that could occur within large swaths of shelf break that
contain underwater canyons or other habitats (e.g., Norfolk Canyon,
part of the Cape Hatteras Special Research Area) associated with high
marine mammal diversity in this region.
In the Gulf of Maine Marine Mammal Mitigation Area, the Action
Proponents would use no more than 200 hours of surface ship hull-
mounted MFAS annually. This measure is designed to reduce exposure of
marine mammals to potentially injurious levels of sound from surface
ship hull-mounted MFAS, the type of active sonar with the highest power
source used in the Study Area.

[[Page 20023]]

Additionally, the action proponents would implement four mitigation
areas specifically designed to protect NARW. These include the
Northeast North Atlantic Right Whale Mitigation Area, Jacksonville
Operating Area North Atlantic Right Whale Mitigation Area, Southeast
North Atlantic Right Whale Mitigation Area, and the Dynamic North
Atlantic Right Whale Mitigation Areas. These areas are designed to
reduce exposure of NARWs to acoustic and explosive stressors as well as
vessel strike risk in foraging critical habitat, reproduction critical
habitat, and in areas and times when the species has a higher
occurrence in these areas. The Northeast North Atlantic Right Whale
Mitigation Area would also protect other marine mammal species,
including those with BIAs that overlap the mitigation area, including
fin whale, humpback whale, minke whale, sei whale, and harbor porpoise
(LaBrecque et al., 2015).
In addition to the nature and context of the disturbance, including
whether take occurs in a known BIA, species-specific factors affect the
severity of impacts to individual animals and population consequences
of disturbance. Keen et al. (2021) identifies three population
consequences of disturbance themes: life history traits, environmental
conditions, and disturbance source characteristics. Life history traits
considered in Keen et al. (2021) include movement ecology (whether
animals are resident, nomadic, or migratory), reproductive strategy
(capital breeders, income breeders, or mixed), body size (based on size
and life stage), and pace of life (slow or fast).
Regarding movement ecology, resident animals that have small home
ranges relative to the size and duration of an impact zone would have a
higher risk of repeated exposures to an ongoing activity. Animals that
are nomadic over a larger range may have less predictable risk of
repeated exposure. For resident and nomadic populations, overlap of a
stressor with feeding or reproduction depends more on time of year
rather than location in their habitat range. In contrast, migratory
animals may have higher or reduced potential for exposure during
feeding and reproduction based on both location, time of the year, and
duration of an activity. The risk of repeated exposure during
individual events may be lower during migration as animals maintain
directed transit through an area.
Reproduction is energetically expensive for female marine mammals,
and reproductive strategy can influence an animal's sensitivity to
disturbance. Mysticetes and phocids are capital breeders. Capital
breeders rely on their capital, or energy stores, to migrate, maintain
pregnancy, and nurse a calf. Capital breeders would be more resilient
to short-term foraging disruption due to their reliance on built-up
energy reserves, but are vulnerable to prolonged foraging impacts
during gestation. Otariids and most odontocetes are income breeders,
which rely on some level of income, or regular foraging, to give birth
and nurse a calf. Income breeders would be more sensitive to the
consequences of disturbances that impact foraging during lactation.
Some species exhibit traits of both, such as beaked whales.
Smaller animals require more food intake per unit body mass than
large animals. They must consume food on a regular basis and are likely
to be non-migratory and income breeders. The smallest odontocetes, the
porpoises, must maintain high metabolisms to maintain thermoregulation
and cannot rely on blubber stores for long periods of time, whereas
larger odontocetes can more easily thermoregulate. The larger size of
other odontocetes is an adaptation for deep diving that allows them to
access high quality mesopelagic and bathypelagic prey. Both small and
large odontocetes have lower foraging efficiency than the large whales.
The filter-feeding large whales (mysticetes) consume most of their food
within several months of the year and rely on extensive lipid reserves
for the remainder of the year. The metabolism of mysticetes allows for
fasting while seeking prey patches during foraging season and prolonged
periods of fasting outside of foraging season (Goldbogen et al., 2023).
Their energy stores support capital breeding and long migrations. The
effect of a temporary feeding disturbance is likely to have
inconsequential impacts to a mysticete but may be consequential for
small cetaceans. Despite their relatively smaller size, amphibious
pinnipeds have lower thermoregulatory requirements because they spend a
portion of time on land. For purposes of this assessment, marine
mammals were generally categorized as small (less than 10 ft (3.05 m)),
medium (10-30 ft (3.05-9.1 m)), or large (more than 30 ft (9.1 m))
based on length.
Populations with a fast pace of life are characterized by early age
of maturity, high birth rates, and short life spans, whereas
populations with a slow pace of life are characterized by later age of
maturity, low birth rates, and long life spans. The consequences of
disturbance in these populations differ. Although reproduction in
populations with a fast pace of life are more sensitive to foraging
disruption, these populations are quick to recover. Reproduction in
populations with a slow pace of life is resilient to foraging
disruption, but late maturity and low birth rates mean that long-term
impacts to breeding adults have a longer-term effect on population
growth rates. Pace of life was categorized for each species in this
analysis by comparing age at sexual maturity, birth rate interval, life
span, body size, and feeding and reproductive strategy.
Southall et al. (2023) also identified factors that inform a
population's vulnerability. The authors describe a framework to assess
risk to populations from specific industry impact scenarios at
different locations or times of year. While this approach may not be
suitable for many military readiness activities, for which alternate
spatial or seasonal scenarios are not usually feasible, the concepts
considered in that framework's population vulnerability assessment are
useful in this analysis, including population status (endangered or
threatened), population trend (decreasing, stable, or increasing),
population size, and chronic exposure to other anthropogenic or
environmental stressors (e.g., fisheries interactions, pollution,
climate change, etc.). These factors are also considered when assessing
the overall vulnerability of a stock to repeated effects from acoustic
and explosive stressors.
In consideration of the factors outlined above, if impacts to
individuals increase in magnitude or severity such that repeated and
sequential higher severity impacts occur (the probability of this goes
up for an individual the higher total number of takes it has) or the
total number of moderate to more severe impacts increases
substantially, especially if occurring across sequential days, then it
becomes more likely that the aggregate effects could potentially
interfere with feeding enough to reduce energy budgets in a manner that
could impact reproductive success via longer cow-calf intervals,
terminated pregnancies, or calf mortality. It is important to note that
these impacts only accrue to females, which only comprise approximately
50 percent of the population. Based on energetic models, it takes
energetic impacts of a significantly greater magnitude to cause the
death of an adult marine mammal, and females will always terminate a
pregnancy or stop lactating before allowing their health to
deteriorate. Also, the death of an adult female has significantly more
impact on population growth rates than reductions in reproductive
success, while the death of an adult male has very little effect on

[[Page 20024]]

population growth rates. However, as explained earlier, such severe
impacts from the specified activities would be very infrequent and not
considered likely to occur at all for most species and stocks. We note
that the negligible impact analysis is inherently a two-tiered
assessment that first evaluates the anticipated impacts of the
activities on marine mammals individuals, and then if impacts are
expected to reproduction or survival of any individuals further
evaluates the effects of those individual impacts on rates of
reproduction and survival of the species or stock, in the context of
the status of the species or stock. The analyses below in some cases
address species collectively if they occupy the same functional hearing
group (i.e., very-low, low, high, and very high-frequency cetaceans),
share similar life history strategies, and/or are known to behaviorally
respond similarly to acoustic stressors. Because some of these groups
or species share characteristics that inform the impact analysis
similarly, it would be duplicative to repeat the same analysis for each
species. In addition, similar species typically have the same hearing
capabilities and behaviorally respond in the same manner.
Thus, our analysis below considers the effects of the specified
activities on each affected species or stock even where discussion is
organized by functional hearing group and/or information is evaluated
at the group level. Where there are meaningful differences between a
species or stock that would further differentiate the analysis, they
are either described within the section or the discussion for those
species or stocks is included as a separate subsection. Specifically
below, we first give broad descriptions of the mysticete, odontocete,
and pinniped groups and then differentiate into further groups as
appropriate.
Mysticetes
This section builds on the broader discussion above and brings
together the discussion of the different types and amounts of take that
different stocks will incur, the applicable mitigation for each stock,
and the status and life history of the stocks to support the negligible
impact determinations for each stock. We have already described above
why we believe the incremental addition of the small number of low-
level auditory injury takes will not have any meaningful effect towards
inhibiting reproduction or survival. We have also described above in
this section the unlikelihood of any masking or habitat impacts having
effects that would impact the reproduction or survival of any of the
individual marine mammals affected by the Action Proponents'
activities. For mysticetes, there is no predicted non-auditory injury
from explosives for any stock. Regarding the severity of individual
takes by Level B harassment by behavioral disturbance for mysticetes,
the majority of these responses are anticipated to occur at received
levels below 172 dB, and last from a few minutes to a few hours, at
most, with associated responses most likely in the form of moving away
from the source, foraging interruptions, vocalization changes, or
disruption of other social behaviors, lasting from a few minutes to
several hours. Much of the discussion below focuses on the behavioral
effects and the mitigation measures that reduce the probability or
severity of effects in biologically important areas or other habitat.
Because there are multiple stock-specific factors in relation to the
status of the species, as well as mortality take for several stocks, at
the end of the section we break out stock-specific findings.
In table 81 below for mysticetes, we indicate the total annual
mortality, Level A harassment, and Level B harassment, and a number
indicating the instances of total take as a percentage of abundance.
In table 82 below, we indicate the status, life history traits,
important habitats, and threats that inform our analysis of the
potential impacts of the estimated take on the affected mysticete
stocks.

[[Page 20025]]

Table 81--Annual Estimated Take by Level B Harassment, Level A Harassment, and Mortality and Related Information for Mysticetes in the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum
annual
Maximum Maximum Maximum Maximum harassment Season(s) with 40 Region(s) with 40
Marine mammal species Stock NMFS stock NMSDD annual annual annual annual as percent of take or percent of take or
abundance abundance Level B Level A mortality take percentage greater greater
harassment harassment of stock
abundance
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale......... Western............... * 372 216 414 2 0 416 112 Spring (45 percent) Northeast (70
Winter (40 percent). percent).
Blue whale......................... Western North Atlantic * Unk 19 71 1 0 72 Und N/A................... Mid-Atlantic (48
percent).
Bryde's whale...................... Primary............... * N/A N/A 11 0 0 11 Und Winter (48 percent)... High Seas (100
percent).
Fin whale.......................... Western North Atlantic * 6,802 1,075 2,616 21 0.29 2,637 39 N/A................... Mid-Atlantic (62
percent).
Humpback whale..................... Gulf of Maine......... * 1,396 690 844 12 0.57 856.57 61 Spring (50 percent)... Mid-Atlantic (48
percent)
Northeast (43
percent).
Minke whale........................ Canadian East Coast... * 21,968 1,339 4,643 56 0.29 4,699 21 Winter (51 percent)... Southeast (47
percent).
Rice's whale....................... Northern Gulf of * 51 118 303 3 0 306 600 Winter (44 percent)... Gulf of America (100
America. percent).
Sei whale.......................... Nova Scotia........... * 6,292 316 747 7 0.29 754.29 12 Spring (41 percent)... N/A.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: N/A = Not Applicable. NMSDD abundances are averages only within the U.S. EEZ.
* Indicates which abundance estimate was used to calculate the maximum annual take as a percentage of abundance, either the NMFS SAR (Hayes et al., 2024) or the NMSDD (table 2.4-1 in appendix
A of the application). Please refer to the following section for details on which abundance estimate was selected.

Table 82--Life History Traits, Important Habitat, and Threats to Mysticetes in the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Annual
mortality/
Reproductive Chronic risk UME, oil spill, ESA- designated BIAs (LaBrecque Other important serious
Marine mammal species Stock ESA status MMPA status Movement ecology Movement ecology Body size strategy Pace of life factors other critical habitat et al. 2015) habitat Population trend PBR injury (from
other human
activities)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale.... Western.......... Endangered....... Depleted......... Migratory........ Migratory........ Large............ Capital.......... Slow............ Vessel strikes, UME (declared Critical Yes: Feeding Great South Decreasing...... 0.73 14.8
Strategic........ entanglement, 2017, active). Habitat: (n=3), Channel/Georges
habitat Northeastern US Migration Bank Shelf
degradation, Foraging Area (n=1), Break, Gulf of
pollution, Unit 1, Reproduction ME Mating,
vessel Southeastern US (n=2). Migratory
disturbance, Calving Area Corridor
ocean noise, Unit 2. Scotian Shelf,
climate change. Southeast
Atlantic
Calving,
Southern New
England.
Blue whale.................... Western North Endangered....... Depleted......... Migratory........ Migratory........ Large............ Capital.......... Slow............ Vessel strikes, No.............. No.............. No.............. None identified. Unk, but 0.8 0
Atlantic. Strategic........ entanglement, possibly
habitat increasing.
degradation,
pollution,
vessel
disturbance,
ocean noise,
climate change.

[[Page 20026]]

Bryde's whale................. Primary.......... Not Listed....... ................. Unknown, likely Unknown, likely Large............ Capital.......... Slow............ Vessel strikes, No.............. No.............. No.............. None identified. Unk............. N/A N/A
migratory. migratory. entanglement,
habitat
degradation,
pollution,
vessel
disturbance,
ocean noise,
climate change.
Fin whale..................... Western North Endangered....... Depleted......... Migratory........ Migratory........ Large............ Capital.......... Slow............ Vessel strikes, No.............. No.............. Yes: Feeding East of Montauk Unk............. 11 2.05
Atlantic. Strategic........ entanglement, (n=3). Point, Southern
habitat Gulf of ME.
degradation,
pollution,
vessel
disturbance,
ocean noise,
climate change.
Humpback whale................ Gulf of Maine.... Not Listed....... Not Depleted..... Migratory........ Migratory........ Large............ Capital.......... Slow............ Vessel strikes, UME (declared No.............. Yes: Feeding Gulf of ME Increasing...... 22 12.15
Not Strategic.... entanglement, 2017, active). (n=1). Child, Gulf of
habitat ME Parent, Mid-
degradation, Atlantic Shelf,
pollution, NY Bight
vessel Parent, South
disturbance, New England.
ocean noise,
climate change.
Minke whale................... Canadian East Not Listed....... Not Depleted..... Migratory........ Migratory........ Med/Large........ Capital.......... Slow............ Vessel strikes, UME (declared No.............. Yes: Feeding Central Gulf of Unk............. 170 9.4
Coast. Not Strategic.... entanglement, 2017, active). (n=2). ME/Parker Ridge/
habitat Cashes Ledge,
degradation, Southwestern
pollution, Gulf of ME/
vessel Georges Bank.
disturbance,
climate change,
disease.

[[Page 20027]]

Rice's whale.................. Northern Gulf of Endangered....... Depleted......... Nomadic.......... Nomadic.......... Large............ Capital.......... Slow............ Vessel strike, Small stock Proposed Yes: Small and Expanded Range, Decreasing...... 0.1 0.5
America. Strategic........ ocean noise, size, DWH. Critical resident Northeastern
energy Habitat: population. Gulf of America.
exploration and Proposed Gulf
development, of America 100-
oil spills, 400 m isobath.
fisheries and
aquaculture
interaction,
ocean debris,
small
population
size, limited
distribution,
climate change.
Sei whale..................... Nova Scotia...... Endangered....... Depleted......... Migratory........ Migratory........ Large............ Capital.......... Slow............ Vessel strike, No.............. No.............. Yes: Feeding Gulf of ME...... Unk............. 6.2 0.6
Strategic........ entanglement, (n=1).
ocean noise,
climate change.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Unk = Unknown; N/A = Not Applicable.

[[Page 20028]]

North Atlantic Right Whale (Western Stock)--
North Atlantic right whales are listed as endangered under the ESA
and as both a depleted and strategic stock under the MMPA. The current
stock abundance estimate is 372 animals. As described in the Unusual
Mortality Events section, a UME has been designated for NARW. North
Atlantic right whales are migratory, though they have been detected
across their range year-round. Detections in the mid-Atlantic are
occurring more frequently (Engelhaupt et al. 2023), and Navy's AFTT
Phase IV Density Technical Report predicts a NARW density in the Mid-
Atlantic Bight that is almost an order of magnitude higher from 2010-
2019 compared to 2003-2009, which is consistent with visual and
acoustic surveys showing an increase in the use of the region (Davis et
al., 2020; O'Brien et al., 2022).
As described in the Description of Marine Mammals and Their Habitat
in the Area of the Specified Activities section, the AFTT Study Area
overlaps the NARW migratory corridor BIA, which represent areas and
months within which a substantial portion of a species or population is
known to migrate (LeBrecque et al. 2015). The Study Area also overlaps
three seasonal feeding BIAs in the northeast Atlantic, a seasonal
mating BIA in the central Gulf of Maine, and a seasonal calving BIA in
the southeast Atlantic (LaBrecque et al. 2015), as well as important
feeding habitat in southern New England, primarily along the western
side of Nantucket Shoals (Estabrook et al., 2022; Kraus et al., 2016;
Leiter et al., 2017; O'Brien et al., 2022, Quintano-Rizzo et al.,
2021). Additionally, the AFTT Study Area overlaps ESA-designated
critical habitat for the NARW (Unit 1 and Unit 2) as described in the
Critical Habitat section of this proposed rule.
NARW are threatened due to a low population abundance, compromised
body condition, high mortality rates, and low reproductive rates. They
face several chronic anthropogenic and non-anthropogenic risk factors,
including vessel strike, entanglement, and climate change, among
others. Recent studies have reported individuals showing high stress
levels (e.g., Corkeron et al., 2017) and poor health, which has further
implications on reproductive success and calf survival (Christiansen et
al., 2020; Stewart et al., 2021; Stewart et al., 2022; Pirotta et al.
2024). Given these factors, the status of the NARW population is of
heightened concern and, therefore, additional analysis is warranted.
As shown in table 81, the maximum annual allowable instances of
take under this proposed rule by Level A Harassment and Level B
harassment is 2 and 414, respectively. Given the current status of the
NARW, the loss of even one individual could significantly impact the
population. However, no mortality is anticipated or proposed for
authorization, and nor is any non-auditory injury. The total take
allowable across all 7 years of the rule is indicated in table 49.
Regarding the potential takes associated with auditory impairment,
as described in the Auditory Injury from Sonar Acoustic Sources and
Explosives and Non-Auditory Injury from Explosives section above, any
takes in the form of TTS are expected to be lower-level, of short
duration (from minutes to, at most, several hours or less than a day),
and mostly not in a frequency band that would be expected to interfere
with NARW communication or other important low-frequency cues. Any
associated lost opportunities or capabilities individuals might
experience as a result of TTS would not be at a level or duration that
would be expected to impact reproductive success or survival. For
similar reasons, while auditory injury impacts last longer, the low
anticipated levels of AUD INJ that could be reasonably expected to
result from these activities are unlikely to have any effect on
fitness.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 172 dB SPL and last from a
few minutes to a few hours, at most, with associated responses most
likely in the form of moving away from the source, foraging
interruptions, vocalization changes, or disruption of other social
behaviors, lasting from a few minutes to several hours. NARWs are
large-bodied capital breeders with a slow pace of life, which would
generally be less susceptible to impacts from shorter duration foraging
disruptions.
Further, as described in the Group and Species-Specific Analyses
section above and the Proposed Mitigation Measures section, mitigation
measures, several of which are designed specifically to reduce impacts
to North Atlantic right whale, are expected to further reduce the
potential severity of impacts through real-time operational measures
that minimize higher level/longer duration exposures and time/area
measures that reduce impacts in high value habitat. Specifically, this
proposed rule includes several proposed geographic mitigation areas for
NARW: Northeast North Atlantic Right Whale Mitigation Area, Gulf of
Maine Mitigation Area, Jacksonville Operating Area North Atlantic Right
Whale Mitigation Area, Southeast North Atlantic Right Whale Mitigation
Area, Dynamic North Atlantic Right Whale Mitigation Areas, MTE Planning
Awareness Mitigation Areas in the northeast and mid-Atlantic, and ship
shock trial mitigation areas. The Northeast North Atlantic Right Whale
Mitigation Area and Southeast North Atlantic Right Whale Mitigation
Area in particular would reduce exposures in times and areas where
impacts would be more likely to affect feeding and energetics (note
that these mitigation areas are not quantitatively accounted for in the
modeling, which means that the mitigation may prevent some of the takes
predicted--though the analysis considers that they could all occur).
Also, because of the proposed mitigation measures, the estimated takes
would be less likely to occur in areas or at times where impacts would
be likely to affect feeding and energetics or important cow/calf
interactions that could lead to reduced reproductive success or
survival, including those in areas known to be biologically important,
and such impacts are not anticipated. Any impacts predicted in the east
coast migratory corridor are less likely to impact individuals during
feeding or breeding behaviors.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In this case, given the
number of takes by harassment as compared to the stock/species
abundance (see table 81), it is likely that some portion of the
individuals taken are taken repeatedly over a small number of days,
particularly in the Northeast (70 percent of the takes predicted are in
this region) during the winter and spring where and when a combined 58
percent of takes of this stock would occur and animals are likely
feeding. This is when North Atlantic right whales have a higher density
at feeding grounds located near and south of Cape Cod, including areas
overlapped by the Narragansett Bay OPAREA in the Northeast Range
Complexes, and in the migratory corridor through the northeast region.
However, given the variety of activity types that contribute to take
across separate exercises conducted at different times and in different
areas, the fact that

[[Page 20029]]

many result from transient activities conducted at sea, and fact that
the number of takes as compared to the abundance is just above 100
percent (112 percent), it is unlikely that takes would be in high
enough numbers for any one individual or occur clumped across
sequential days in a manner likely to impact foraging success and
energetics, or that other behaviors such that reproduction or survival
of any individuals is likely to be impacted.
Given the magnitude and severity of the impacts discussed above to
NARW (considering annual take maxima and the total across 7 years) and
their habitat, and in consideration of the required mitigation measures
and other information presented, the Action Proponents' activities are
unlikely to result in impacts on the reproduction or survival of any
individuals and, thereby, unlikely to affect annual rates of
recruitment or survival. Further, we have considered the UME for NARW
species described above, and even in consideration of the fact that
some of the affected individuals may have compromised health, given the
anticipated impacts of the activity, the proposed take is not expected
to exacerbate the effects of the UME or otherwise impact the
population. For these reasons, we have determined that the take by
harassment anticipated and proposed for authorization would have a
negligible impact on the Western stock of NARW.
Blue Whale (Western North Atlantic Stock)--
Blue whales are listed as endangered under the ESA and as both
depleted and strategic under the MMPA. The stock abundance is currently
unknown, though NMFS' SAR reports an Nmin (minimum
abundance) of 402. The stock's primary range is outside of the AFTT
Study Area. There are no UMEs or other factors that cause particular
concern for this stock, and there are no known biologically important
areas for blue whales in the AFTT Study Area. They are frequently
located in continental shelf waters near eastern Canada but have also
been sighted off the coast of Florida and along the mid-Atlantic ridge
(likely the southern portion of their feeding range). Blue whales face
several chronic anthropogenic and non-anthropogenic risk factors,
including vessel strike, entanglement, and climate change, among
others.
As shown in table 81, the maximum annual allowable instances of
take under this proposed rule by Level A Harassment and Level B
harassment is 1 and 71, respectively. No mortality is anticipated or
proposed for authorization, and nor is any non-auditory injury. The
total take allowable across all 7 years of the rule is indicated in
table 49.
Regarding the potential takes associated with auditory impairment,
as described in the Auditory Injury from Sonar Acoustic Sources and
Explosives and Non-Auditory Injury from Explosives section above, any
takes in the form of TTS are expected to be lower-level, of short
duration, and mostly not in a frequency band that would be expected to
interfere with blue whale communication or other important low-
frequency cues. Any associated lost opportunities or capabilities
individuals might experience as a result of TTS would not be at a level
or duration that would be expected to impact reproductive success or
survival. For similar reasons, while auditory injury impacts last
longer, the low anticipated levels of AUD INJ that could be reasonably
expected to result from these activities are unlikely to have any
effect on fitness.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 172 dB SPL and last from a
few minutes to a few hours, at most, with associated responses most
likely in the form of moving away from the source, foraging
interruptions, vocalization changes, or disruption of other social
behaviors, lasting from a few minutes to several hours. Blue whales are
large-bodied capital breeders with a slow pace of life, and are
therefore generally less susceptible to impacts from shorter duration
foraging disruptions. Further, as described in the Group and Species-
Specific Analyses section above and the Proposed Mitigation Measures
section, mitigation measures are expected to further reduce the
potential severity of impacts through real-time operational measures
that minimize higher level/longer duration exposures and time/area
measures that reduce impacts in high value habitat.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In this case, given the
lower number of takes by harassment as compared to the stock/species
abundance (see table 81), their migratory movement pattern, and the
absence of take concentrated in areas in which animals are known to
congregate, it is unlikely that any individual blue whales would be
taken on more than a small number of days within a year and, therefore,
the anticipated behavioral disturbance is not expected to affect
reproduction or survival.
Given the magnitude and severity of the impacts discussed above to
blue whales (considering annual take maxima and the total across 7
years) and their habitat, and in consideration of the required
mitigation measures and other information presented, the Action
Proponents' activities are not expected to result in impacts on the
reproduction or survival of any individuals, much less affect annual
rates of recruitment or survival. For these reasons, we have determined
that the take by harassment anticipated and proposed for authorization
would have a negligible impact on the Western North Atlantic stock of
blue whales.
Bryde's Whale (Primary)--
This population of Bryde's whales spans the mid- and southern
Atlantic. They have not been designated as a stock under the MMPA, are
not ESA-listed, and there is no current reported population trend.
There are no UMEs or other factors that cause particular concern for
this stock and no known biologically important areas for Bryde's whale
in the AFTT Study Area. Most Bryde's whales congregate in tropical
waters south of the AFTT Study Area, and only occasionally travel as
far north as Virginia. Bryde's whales generally face several chronic
anthropogenic and non-anthropogenic risk factors, including vessel
strike, entanglement, and climate change, among others.
As shown in table 81, the maximum annual allowable instances of
take under this proposed rule by Level B harassment is 11. No mortality
is anticipated or proposed for authorization, and nor is any auditory
or non-auditory injury (Level A harassment). The total take allowable
across all 7 years of the rule is indicated in table 49.
Regarding the potential takes associated with TTS, as described in
the Temporary Threshold Shift section above, any takes in the form of
TTS are expected to be lower-level, of short duration, and mostly not
in a frequency band that would be expected to interfere with Bryde's
whale communication or other important low-frequency cues. Any
associated lost opportunities or capabilities individuals might
experience as a result of TTS would not be at a level or duration that
would be expected to impact reproductive success or survival.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the

[[Page 20030]]

majority of the predicted exposures are expected to be below 172 dB SPL
and last from a few minutes to a few hours, at most, with associated
responses most likely in the form of moving away from the source,
foraging interruptions, vocalization changes, or disruption of other
social behaviors, lasting from a few minutes to several hours. Bryde's
whales are large-bodied capital breeders with a slow pace of life, and
are therefore generally less susceptible to impacts from shorter
duration foraging disruptions.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In this case, given the
low number of takes by harassment (see table 81), their migratory
movement pattern, and the absence of take concentrated in areas in
which animals are known to congregate, it is unlikely that any
individual Bryde's whales would be taken on more than a small number of
days within a year and, therefore, the anticipated behavioral
disturbance is not expected to affect reproduction or survival.
Given the magnitude and severity of the impacts discussed above to
this population of Bryde's whales (considering annual take maxima and
the total across 7 years) and their habitat, and in consideration of
the required mitigation measures and other information presented, the
Action Proponents' activities are not expected to result in impacts on
the reproduction or survival of any individuals, much less affect
annual rates of recruitment or survival. For these reasons, we have
determined that the take by harassment anticipated and proposed for
authorization would have a negligible impact on Bryde's whales.
Fin Whale (Western North Atlantic Stock)--
Fin whales are listed as endangered under the ESA throughout the
species' range and as both depleted and strategic under the MMPA. The
Western North Atlantic stock abundance is 6,802 animals. There are no
UMEs or other factors that cause particular concern for this stock. As
described in the Description of Marine Mammals and Their Habitat in the
Area of the Specified Activities section, the AFTT Study Area overlaps
three fin whale feeding BIAs: (1) June to October in the northern Gulf
of Maine; (2) year-round in the southern Gulf of Maine, and (3) March
to October east of Montauk Point (LeBrecque et al. 2015), and more
recent data supports that these areas remain biologically important
(King et al., 2021; Lomac-MacNair et al., 2022). There is no ESA-
designated critical habitat for fin whales in the AFTT Study Area. The
Western North Atlantic stock of fin whales may be present year-round in
the Atlantic with higher densities near the shelf break in the
Northeast and mid-Atlantic. Densities near feeding areas on the shelf
in the Northeast are higher in the summer. Fin whales face several
chronic anthropogenic and non-anthropogenic risk factors, including
vessel strike, entanglement, and climate change, among others.
As shown in table 81, the maximum annual allowable instances of
take under this proposed rule by Level A Harassment and Level B
harassment is 21 and 2,616, respectively. As indicated, the rule also
allows for up to 2 takes by serious injury or mortality over the course
of the 7-year rule, the impacts of which are discussed above in the
Serious Injury and Mortality section. No non-auditory injury is
anticipated or proposed for authorization. The total take allowable
across all 7 years of the rule is indicated in table 49.
Regarding the potential takes associated with auditory impairment,
as described in the Auditory Injury from Sonar Acoustic Sources and
Explosives and Non-Auditory Injury from Explosives section above, any
takes in the form of TTS are expected to be lower-level, of short
duration (even the longest recovering in less than a day), and mostly
not in a frequency band that would be expected to interfere with fin
whale communication or other important low-frequency cues. Any
associated lost opportunities or capabilities individuals might
experience as a result of TTS would not be at a level or duration that
would be expected to impact reproductive success or survival. For
similar reasons, while auditory injury impacts last longer, the low
anticipated levels of AUD INJ that could be reasonably expected to
result from these activities are unlikely to have any effect on
fitness.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 172 dB SPL and last from a
few minutes to a few hours, at most, with associated responses most
likely in the form of moving away from the source, foraging
interruptions, vocalization changes, or disruption of other social
behaviors, lasting from a few minutes to several hours. Of the takes by
Level B harassment, 5 would occur east of Montauk Point between March
and October, and 52 would occur in the southern Gulf of Maine, both
areas known to be biologically important for fin whale foraging. None
of the takes by Level A harassment would occur in areas known to be
biologically important. However, given that fin whales are large-bodied
capital breeders with a slow pace of life, and are therefore generally
less susceptible to impacts from shorter duration foraging disruptions,
as well as the small number of takes anticipated to occur in the BIA,
we do not anticipate that takes in this BIA would occur to any
individual fin whale on more than a small number of days within a year,
as described further below. Further, as described in the Group and
Species-Specific Analyses section above and the Proposed Mitigation
Measures section, mitigation measures are expected to further reduce
the potential severity of impacts through real-time operational
measures that minimize higher level/longer duration exposures and time/
area measures that reduce impacts in high value habitat.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In this case, given the
number of takes by harassment as compared to the stock/species
abundance (see table 81), it is likely that some portion of the
individuals taken are taken repeatedly over a small number of days.
However, given the variety of activity types that contribute to take
across separate exercises conducted at different times and in different
areas, and the fact that many result from transient activities
conducted at sea, it is unlikely that repeated takes would occur either
in numbers or clumped across sequential days in a manner likely to
impact foraging success and energetics or other behaviors such that
reproduction or survival of any individuals is are likely to be
impacted. Further, this stock is migratory, and the takes are not
concentrated within a specific season.
As analyzed and described in the Mortality section above, given the
status of the stock and in consideration of other ongoing human-caused
mortality, the M/SI proposed for authorization for the Western North
Atlantic stock of fin whales (2 over the course of the 7-year rule, or
0.29 annually) would not, alone, be expected to adversely affect the
stock through rates of recruitment or survival. Given the magnitude and
severity of the take by harassment discussed above and any anticipated
habitat impacts, and in consideration of the required mitigation

[[Page 20031]]

measures and other information presented, the take by harassment
proposed for authorization is unlikely to result in impacts on the
reproduction or survival of any individuals and, thereby, unlikely to
affect annual rates of recruitment or survival either alone or in
combination with the M/SI proposed for authorization. For these
reasons, we have determined that the take anticipated and proposed for
authorization would have a negligible impact on the Western North
Atlantic stock of fin whales.
Humpback Whale (Gulf of Maine Stock)--
The West Indies DPS of humpback whales is not listed as threatened
or endangered under the ESA, and the Gulf of Maine stock, which
includes individuals from the West Indies DPS, is not considered
depleted or strategic under the MMPA. The stock abundance is 1,396
animals. As described in the Description of Marine Mammals and Their
Habitat in the Area of the Specified Activities section, humpback
whales along the Atlantic Coast have been experiencing an active UME as
elevated humpback whale mortalities have occurred along the Atlantic
coast from Maine through Florida since January 2016. Of the cases
examined, approximately 40 percent had evidence of human interaction
(vessel strike or entanglement). As also described in the Description
of Marine Mammals and Their Habitat in the Area of the Specified
Activities section, the AFTT Study Area overlaps a humpback whale
feeding BIA (LeBrecque et al. 2015). This BIA is further supported by
more recent information that suggests that the Gulf of Maine, Mid-
Atlantic Shelf, New York Bight, and south New England are all important
for humpback whale feeding (Brown et al., 2019; Hayes et al., 2019;
Aschettino et al., 2020; Davis et al., 2020; Zeh et al., 2020; King et
al., 2021; Pershing et al., 2021; Stepanuk et al., 2021; Zoidis et al.,
2021; Lomac-MacNair et al., 2022; Smith et al., 2022). There is no ESA-
designated critical habitat for the Gulf of Maine stock of humpback
whales given that the associated DPS is not ESA-listed. The Gulf of
Maine stock of humpback whales have particularly strong site fidelity
in the Gulf of Maine feeding grounds March to December and in the
Caribbean calving grounds from December to May. Humpback whales,
however, may occur in the AFTT Study Area, particularly in the mid-
Atlantic and Northeast, year-round. They occur near the Chesapeake Bay
mouth except in the summer. Humpback whales face several chronic
anthropogenic and non-anthropogenic risk factors, including vessel
strike, entanglement, and climate change, among others.
As shown in table 81, the maximum annual allowable instances of
take under this proposed rule by Level A Harassment and Level B
harassment is 12 and 844, respectively. As indicated, the rule also
allows for up to 4 takes by serious injury or mortality over the course
of the 7-year rule, the impacts of which are discussed above in the
Serious Injury and Mortality section. No non-auditory injury is
anticipated or proposed for authorization. The total take allowable
across all 7 years of the rule is indicated in table 49.
Regarding the potential takes associated with auditory impairment,
as described in the Auditory Injury from Sonar Acoustic Sources and
Explosives and Non-Auditory Injury from Explosives section above, any
takes in the form of TTS are expected to be lower-level, of short
duration (even the longest recovering in several hours or less than a
day), and mostly not in a frequency band that would be expected to
interfere with humpback whale communication or other important low-
frequency cues. Any associated lost opportunities or capabilities
individuals might experience as a result of TTS would not be at a level
or duration that would be expected to impact reproductive success or
survival. For similar reasons, while auditory injury impacts last
longer, the low anticipated levels of AUD INJ that could be reasonably
expected to result from these activities are unlikely to have any
effect on fitness.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 172 dB SPL and last from a
few minutes to a few hours, at most, with associated responses most
likely in the form of moving away from the source, foraging
interruptions, vocalization changes, or disruption of other social
behaviors, lasting from a few minutes to several hours. Humpback whales
are large-bodied capital breeders with a slow pace of life, and are
therefore generally less susceptible to impacts from shorter duration
foraging disruptions. Further, as described in the Group and Species-
Specific Analyses section above and the Proposed Mitigation Measures
section, mitigation measures are expected to further reduce the
potential severity of impacts through real-time operational measures
that minimize higher level/longer duration exposures and time/area
measures that reduce impacts in high value habitat.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In this case, given the
number of takes by harassment as compared to the stock/species
abundance (see table 81) and the fact that a portion of the takes occur
in BIAs, it is likely that some portion of the individuals taken are
taken repeatedly over a small number of days. However, given the
migratory nature of the stock, the variety of activity types that
contribute to take across separate exercises conducted at different
times and in different areas (i.e., not concentrated within a specific
region and season), and the fact that many result from transient
activities conducted at sea, it is unlikely that repeated takes would
occur either in numbers or clumped across sequential days in a manner
likely to impact foraging success and energetics or other behaviors
such that reproduction or survival of any individuals likely to be
impacted. Further, as noted above, humpback whales are large-bodied
capital breeders with a slow pace of life, and are therefore generally
less susceptible to impacts from shorter duration foraging disruptions.
As analyzed and described in the Mortality section above, given the
status of the stock and in consideration of other ongoing human-caused
mortality, the M/SI proposed for authorization for Gulf of Maine
humpback whales (4 over the course of the 7-year rule, or 0.57
annually) would not, alone, be expected to adversely affect the stock
through rates of recruitment or survival. Given the magnitude and
severity of the take by harassment discussed above and any anticipated
habitat impacts, and in consideration of the required mitigation
measures and other information presented, the take by harassment
proposed for authorization is unlikely to result in impacts on the
reproduction or survival of any individuals and, thereby, unlikely to
affect annual rates of recruitment or survival either alone or in
combination with the M/SI proposed for authorization. Last, we have
both considered the effects of the UME on this stock in our analysis
and findings regarding the impact of the activity on the stock, and,
also, determined that we do not expect the proposed take to exacerbate
the effects of the UME or otherwise impact the population. For these
reasons, we have determined that the take anticipated and proposed for
authorization would have a negligible

[[Page 20032]]

impact on the Gulf of Maine stock of humpback whales.
Minke Whale (Canadian East Coast Stock)--
Minke whales are not listed as threatened or endangered under the
ESA and are not considered depleted or strategic under the MMPA. The
stock abundance is 21,968 animals (Hayes et al., 2024). The stock's
range extends beyond the AFTT Study Area. There is an ongoing UME for
minke whales along the Atlantic Coast from Maine through South
Carolina, with the highest number of deaths in Massachusetts, Maine,
and New York. Preliminary findings in several of the whales have shown
evidence of human interactions or infectious diseases. However, we note
that the stock abundance is greater than 21,000 and the take proposed
for authorization is not expected to exacerbate the UME in any way. As
described in the Description of Marine Mammals and Their Habitat in the
Area of the Specified Activities section, the AFTT Study Area overlaps
two minke whale feeding BIAs (Labrecque et al., 2015; CeTAP, 1982;
Murphy, 1995). There is no ESA-designated critical habitat for minke
whales, as the species is not ESA-listed. Minke whales face several
chronic anthropogenic and non-anthropogenic risk factors, including
vessel strike, entanglement, and climate change, among others.
As shown in table 81, the maximum annual allowable instances of
take under this proposed rule by Level A Harassment and Level B
harassment is 56 and 4,643, respectively. As indicated, the rule also
allows for up to 2 takes by serious injury or mortality over the course
of the 7-year rule, the impacts of which are discussed above in the
Serious Injury and Mortality section. The total take allowable across
all 7 years of the rule is indicated in table 49.
Regarding the potential takes associated with auditory impairment,
as described in the Auditory Injury from Sonar Acoustic Sources and
Explosives and Non-Auditory Injury from Explosives section above, any
takes in the form of TTS are expected to be lower-level, of short
duration, and mostly not in a frequency band that would be expected to
interfere with minke whale communication or other important low-
frequency cues. Any associated lost opportunities or capabilities
individuals might experience as a result of TTS would not be at a level
or duration that would be expected to impact reproductive success or
survival. For similar reasons, while auditory injury impacts last
longer, the low anticipated levels of AUD INJ that could be reasonably
expected to result from these activities are unlikely to have any
effect on fitness.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 172 dB SPL and last from a
few minutes to a few hours, at most, with associated responses most
likely in the form of moving away from the source, foraging
interruptions, vocalization changes, or disruption of other social
behaviors, lasting from a few minutes to several hours. Minke whales
are medium-to-large-bodied capital breeders with a slow pace of life,
and are therefore generally less susceptible to impacts from shorter
duration foraging disruptions. Further, as described in the Group and
Species-Specific Analyses section above and the Proposed Mitigation
Measures section, mitigation measures are expected to further reduce
the potential severity of impacts through real-time operational
measures that minimize higher level/longer duration exposures and time/
area measures that reduce impacts in high value habitat.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In this case, given the
lower number of takes by harassment as compared to the stock/species
abundance (see table 81), their migratory movement pattern, and the
absence of take concentrated in areas in which animals are known to
congregate, it is unlikely that any individual minke whales would be
taken on more than a small number of days within a year and, therefore,
the anticipated behavioral disturbance is not expected to affect
reproduction or survival.
As analyzed and described in the Mortality section above, given the
status of the stock and in consideration of other ongoing human-caused
mortality, the M/SI proposed for authorization for Canadian East Coast
minke whales (2 over the course of the 7-year rule, or 0.29 annually)
would not, alone, be expected to adversely affect the stock through
rates of recruitment or survival. Given the magnitude and severity of
the take by harassment discussed above and any anticipated habitat
impacts, and in consideration of the required mitigation measures and
other information presented, the take by harassment proposed for
authorization is unlikely to result in impacts on the reproduction or
survival of any individuals and, thereby, unlikely to affect annual
rates of recruitment or survival either alone or in combination with
the M/SI proposed for authorization. Last, we have both considered the
effects of the UME on this stock in our analysis and findings regarding
the impact of the activity on the stock, and, also, determined that we
do not expect the proposed take to exacerbate the effects of the UME or
otherwise impact the population. For these reasons, we have determined
that the take anticipated and proposed for authorization would have a
negligible impact on the Canadian East Coast stock of minke whales.
Rice's Whale (Northern Gulf of America Stock)--
Rice's whales are listed as endangered under the ESA and as both
depleted and strategic under the MMPA. The stock abundance is 51
animals (Hayes et al., 2024). The AFTT Study Area overlaps the Rice's
whale small and resident population BIA (LaBrecque et al. 2015, further
supported by more recent information (e.g., Rosel et al. 2021, Garrison
et al. 2024)), as well as proposed ESA-designated critical habitat (88
FR 47453, July 24, 2023), as described in the Description of Marine
Mammals in the Area of Specified Activities section. Rice's whales face
several chronic anthropogenic and non-anthropogenic risk factors,
including vessel strike, energy exploration and development, climate
change, and a limited population size and distribution, among others.
Although this stock is not experiencing a UME, given the stock's
status, low abundance and vulnerability, constricted range, and
lingering effects of exposure to oil from the DWH oil spill (which
include adverse health effects on individuals, as well as population
effects), additional analysis is warranted.
Although there is new evidence of Rice's whale occurrence in the
central and western Gulf of America from passive acoustic detections
(Soldevilla et al., 2022; 2024), the highest densities of Rice's whales
remain confined to the northeastern Gulf of America core habitat, where
their occurrence would overlap activities conducted in the offshore
portions of the Naval Surface Warfare Center, Panama City Division
Testing Area. The number of individuals that occur in the central and
western Gulf of America and nature of their use of this area is poorly
understood. Soldevilla et al. (2022) suggest that more than one
individual was present on at least one occasion, as overlapping calls
of different call subtypes were recorded in that instance, but also
state that call detection rates suggest that either multiple
individuals

[[Page 20033]]

are typically calling or that individual whales are producing calls at
higher rates in the central/western Gulf of America. Soldevilla et al.
(2024) provide further evidence that Rice's whale habitat encompasses
all 100-400 m depth waters encircling the entire Gulf of America
(including Mexican waters), but they also note that further research is
needed to understand the density of whales in these areas, seasonal
changes in whale density, and other aspects of habitat usage.
As shown in table 81, the maximum annual allowable instances of
take under this proposed rule by Level A Harassment and Level B
harassment is 3 and 303, respectively. No mortality is anticipated or
proposed for authorization, and nor is any non-auditory injury. The
total take allowable across all 7 years of the rule is indicated in
table 49. Most impacts to Rice's whale are due to unmanned underwater
vehicle testing, which may use sonars at a variety of frequencies for
multiple hours most days of the year on the testing range. 44 percent
of takes of this stock would occur during the winter when Rice's whale
densities are predicted to be highest in the northeastern Gulf of
America.
Regarding the potential takes associated with auditory impairment,
as described in the Auditory Injury from Sonar Acoustic Sources and
Explosives and Non-Auditory Injury from Explosives section above, any
takes in the form of TTS are expected to be lower-level, of short
duration (from minutes to, at most, several hours or less than a day),
and mostly not in a frequency band that would be expected to interfere
with Rice's whale communication or other important low-frequency cues.
Any associated lost opportunities or capabilities individuals might
experience as a result of TTS would not be at a level or duration that
would be expected to impact reproductive success or survival. For
similar reasons, while auditory injury impacts last longer, the low
anticipated levels of AUD INJ that could be reasonably expected to
result from these activities are unlikely to have any effect on
fitness.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 172 dB SPL and last from a
few minutes to a few hours, at most, with associated responses most
likely in the form of moving away from the source, foraging
interruptions, vocalization changes, or disruption of other social
behaviors, lasting from a few minutes to several hours. Rice's whales
are large-bodied capital breeders with a slow pace of life, which would
generally be expected to be less susceptible to impacts from shorter-
term foraging disruption. Further, as described in the Group and
Species-Specific Analyses section above and the Proposed Mitigation
Measures section, mitigation measures are expected to further reduce
the potential severity of impacts through real-time operational
measures that minimize higher level/longer duration exposures and time/
area measures that reduce impacts in high value habitat. In particular,
this proposed rulemaking includes a Rice's Whale Mitigation Area that
overlaps the Rice's whale small and resident population area identified
by NMFS in its 2016 status review (Rosel et al., 2016). This area
encompasses the area where Rice's whales are most likely to occur as
well as most of the eastern portion of proposed critical habitat.
Within this area, the Action Proponents must not use more than 200
hours of surface ship hull-mounted mid-frequency active sonar annually
and must not detonate in-water explosives (including underwater
explosives and explosives deployed against surface targets) except
during mine warfare activities. Additionally, the Ship Shock Trial
Mitigation Area would ensure that the northern Gulf of America ship
shock trial box is situated outside of the Rice's whale core
distribution area. These restrictions would reduce the severity of
impacts to Rice's whales by reducing their exposure to levels of sound
from sonar or explosives that would have the potential to cause injury,
or mortality, thereby reducing the likelihood of those effects and,
further, minimizing the severity of behavioral disturbance.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In this case, given the
number of takes by harassment as compared to the stock/species
abundance (see table 81), it is likely that some portion of the
individuals taken are taken repeatedly over a moderate number of days.
However, unlike most large whales, Rice's whales are not migratory but
are nomadic, so the risk of repeated impacts on individuals is likely
similar within the population as animals move throughout their range.
Further, given the variety of activity types that contribute to take
across separate exercises conducted at different times and in different
areas, and the fact that many result from transient activities
conducted at sea, it is unlikely that takes would occur either in
numbers or clumped across sequential days in a manner likely to impact
foraging success and energetics or other behaviors such that
reproduction or survival are likely to be impacted. While Rice's whale
core habitat is in the northeastern portion of the Gulf of America
which has been identified as biologically important (LaBrecque et al.
2015), and a majority of takes would occur in that area, additional
important Rice's whale habitat occurs between the 100 m and 400 m (328
ft and 1,312 ft) isobath in the Gulf of America (Soldevilla et al.,
2024; 88 FR 47453, July 24, 2023).
Given the magnitude and severity of the impacts discussed above to
Rice's whale (considering annual take maxima and the total across 7
years) and their habitat, and in consideration of the required
mitigation measures and other information presented, the Action
Proponents' activities are unlikely to result in impacts on the
reproduction or survival of any individuals and, thereby, unlikely to
affect annual rates of recruitment or survival. Last, we are aware that
Rice's whales have experienced lower rates of reproduction and survival
since the DWH oil spill, however, those effects are reflected in the
SARs and other data considered in these analyses and do not change our
findings. For these reasons, we have determined that the take by
harassment anticipated and proposed for authorization would have a
negligible impact on Rice's whale.
Sei Whale (Nova Scotia Stock)--
Sei whales are listed as endangered under the ESA throughout its
range and are considered depleted and strategic under the MMPA. The
Nova Scotia stock abundance is 6,292 animals. There are no UMEs or
other factors that cause particular concern for this stock. As
described in the Description of Marine Mammals and Their Habitat in the
Area of the Specified Activities section, the AFTT Study Area overlaps
a sei whale feeding BIA. There is no ESA-designated critical habitat
for sei whales in the AFTT Study Area. The highest sei whale abundance
in U.S. waters occurs during spring, with sightings concentrated along
the eastern margin of Georges Bank, into the Northeast Channel area,
south of Nantucket, and along the southwestern edge of Georges Bank
(CETAP 1982; Hayes et al. 2024; Kraus et al. 2016; Roberts et al. 2016;
Palka et al. 2017; Cholewiak et al. 2018). Sei whales face several
chronic anthropogenic and non-anthropogenic risk factors, including
vessel strike,

[[Page 20034]]

entanglement, and climate change, among others.
As shown in table 81, the maximum annual allowable instances of
take under this proposed rule by Level A Harassment and Level B
harassment is 7 and 747, respectively. As indicated, the rule also
allows for up to 2 takes by serious injury or mortality over the course
of the 7-year rule, the impacts of which are discussed above in the
Serious Injury and Mortality section. The total take allowable across
all 7 years of the rule is indicated in table 49.
Regarding the potential takes associated with auditory impairment,
as described in the Auditory Injury from Sonar Acoustic Sources and
Explosives and Non-Auditory Injury from Explosives section above, any
takes in the form of TTS are expected to be lower-level, of short
duration, and mostly not in a frequency band that would be expected to
interfere with sei whale communication or other important low-frequency
cues. Any associated lost opportunities or capabilities individuals
might experience as a result of TTS would not be at a level or duration
that would be expected to impact reproductive success or survival. For
similar reasons, while auditory injury impacts last longer, the low
anticipated levels of AUD INJ that could be reasonably expected to
result from these activities are unlikely to have any effect on
fitness.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 172 dB SPL and last from a
few minutes to a few hours, at most, with associated responses most
likely in the form of moving away from the source, foraging
interruptions, vocalization changes, or disruption of other social
behaviors, lasting from a few minutes to several hours. Sei whales are
large-bodied capital breeders with a slow pace of life, and are
therefore generally less susceptible to impacts from shorter duration
foraging disruptions. Further, as described in the Group and Species-
Specific Analyses section above and the Proposed Mitigation Measures
section, mitigation measures are expected to further reduce the
potential severity of impacts through real-time operational measures
that minimize higher level/longer duration exposures and time/area
measures that reduce impacts in high value habitat.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In this case, given the
lower number of takes by harassment as compared to the stock/species
abundance (see table 81) and their migratory movement pattern, it is
unlikely that any individual sei whales would be taken on more than a
small number of days within a year and, therefore, the anticipated
behavioral disturbance is not expected to affect reproduction or
survival.
As analyzed and described in the Mortality section above, given the
status of the stock and in consideration of other ongoing human-caused
mortality, the M/SI proposed for authorization for the Nova Scotia
stock of sei whales (2 over the course of the 7-year rule, or 0.29
annually) would not, alone, be expected to adversely affect the stock
through rates of recruitment or survival. Given the magnitude and
severity of the take by harassment discussed above and any anticipated
habitat impacts, and in consideration of the required mitigation
measures and other information presented, the take by harassment
proposed for authorization is unlikely to result in impacts on the
reproduction or survival of any individuals and, thereby, unlikely to
affect annual rates of recruitment or survival either alone or in
combination with the M/SI proposed for authorization. For these
reasons, we have determined that the take anticipated and proposed for
authorization would have a negligible impact on the Nova Scotia stock
of sei whales.
Odontocetes
This section builds on the broader discussion above and brings
together the discussion of the different types and amounts of take that
different stocks will incur, the applicable mitigation for each stock,
and the status and life history of the stocks to support the negligible
impact determinations for each stock. We have already described above
why we believe the incremental addition of the small number of low-
level auditory injury takes will not have any meaningful effect towards
inhibiting reproduction or survival. We have also described above in
this section the unlikelihood of any masking or habitat impacts having
effects that would impact the reproduction or survival of any of the
individual marine mammals affected by the Action Proponents'
activities. Some odontocete stocks have predicted non-auditory injury
from explosives, discussed further below. Regarding the severity of
individual takes by Level B harassment by behavioral disturbance for
odontocetes, the majority of these responses are anticipated to occur
at received levels below below 178 dB for most odontocete species and
below 154 dB for sensitive species (i.e., beaked whales and harbor
porpoises, for which a lower behavioral disturbance threshold is
applied), and last from a few minutes to a few hours, at most, with
associated responses most likely in the form of moving away from the
source, foraging interruptions, vocalization changes, or disruption of
other social behaviors, lasting from a few minutes to several hours.
Much of the discussion below focuses on the behavioral effects and the
mitigation measures that reduce the probability or severity of effects
in biologically important areas or other habitat. Because there are
multiple stock-specific factors in relation to the status of the
species, as well as mortality take for several stocks, at the end of
the section we break out stock- or group-specific findings.
In table 83 (sperm whales, dwarf sperm whales, and pygmy sperm
whales), table 85 (beaked whales), table 87 (dolphins and small
whales), table 89 (porpoises), and table 91 (pinnipeds), we indicate
the total annual mortality, Level A harassment, and Level B harassment,
and a number indicating the instances of total take as a percentage of
abundance.
In table 84 (sperm whales, dwarf sperm whales, and pygmy sperm
whales), table 86 (beaked whales), table 88 (dolphins and small
whales), table 90 (porpoises), and table 92 (pinnipeds), below, we
indicate the status, life history traits, important habitats, and
threats that inform our analysis of the potential impacts of the
estimated take on the affected odontocete stocks.
Sperm Whales, Dwarf Sperm Whales, and Pygmy Sperm Whales--

[[Page 20035]]

Table 83--Annual Estimated Take by Level B harassment, Level A harassment, and Mortality and Related Information for Atlantic Stocks of Sperm Whale, Dwarf Sperm Whale, and Pygmy Sperm Whale in
the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum
Maximum Maximum annual take
NMFS stock NMSDD annual annual Maximum Maximum as Season(s) with 40 Region(s) with 40
Marine mammal species Stock abundance abundance Level B Level A annual annual percentage percent of take percent of take or
harassment harassment mortality take of stock or greater greater
abundance
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale.......................... Northern Gulf of 1,180 * 1,614 275 0 0.14 275 17 N/A Gulf of America (60
America. percent).
Dwarf sperm whales................... Northern Gulf of 336 * 510 189 22 0 211 41 N/A Gulf of America (96
America \a\. percent).
Pygmy sperm whales................... Northern Gulf of 336 * 510 175 22 0 197 39 N/A Gulf of America (95
America \a\. percent).
Sperm whale.......................... North Atlantic......... * 5,895 4,242 12,590 7 0.29 12,597 214 N/A Mid-Atlantic (80
percent).
Dwarf sperm whale.................... Western North Atlantic * 9,474 2,426 6,326 180 0 6,506 69 N/A Mid-Atlantic (73
\a\. percent).
Pygmy sperm whales................... Western North Atlantic * 9,474 2,426 6,294 176 0 6,470 68 N/A Mid-Atlantic (72
\a\. percent).
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: N/A = Not Applicable. NMSDD abundances are averages only within the U.S. EEZ.
* Indicates which abundance estimate was used to calculate the maximum annual take as a percentage of abundance, either the NMFS SAR (Hayes et al., 2024) or the NMSDD (table 2.4-1 in appendix
A of the application). Please refer to the following section for details on which abundance estimate was selected.
\a\ Because Kogia sima and K. breviceps are difficult to differentiate at sea, the reported abundance estimates for the Western North Atlantic stock are for both species of Kogia combined.

Table 84--Life History Traits, Important Habitat, and Threats to Sperm Whale, Dwarf Sperm Whale, and Pygmy Sperm Whale in the AFTT Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Annual
Reproductive Pace of Chronic risk UME, oil ESA- designated BIAs (Labrecque Other important mortality
Marine mammal species Stock ESA status MMPA status Movement ecology Body size strategy life factors spill, other critical et al. 2015) habitat Population trend PBR serious
habitat injury
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale.................... Northern Gulf of Endangered... Depleted.......... Resident-migratory Large..... Income......... Slow...... Vessel strike, ............ No............. No............. None identified.. Unk, but possibly 2 9.6
America. Strategic......... entanglement, stable.
ocean noise,
marine debris,
oil spills and
contaminants,
energy
exploration and
development,
climate change.
Dwarf sperm whales............. Northern Gulf of Not Listed... Not Depleted...... Unknown........... Small-Med. Income......... Fast...... Entanglement, ............ No............. No............. None identified.. Unk.............. 2.5 31
America. Not Strategic..... vessel strike,
marine debris,
ocean noise,
energy
exploration and
development, oil
spills, disease,
climate change.
Pygmy sperm whales............. Northern Gulf of Not Listed... Not Depleted...... Unknown........... Small-Med. Income......... Fast...... Entanglement, ............ No............. No............. None identified.. Unk.............. 2.5 31
America. Not Strategic..... vessel strike,
marine debris,
ocean noise,
energy
exploration and
development, oil
spills, disease,
climate change.
Sperm whale.................... North Atlantic.... Endangered... Depleted.......... Nomadic........... Large..... Income......... Slow...... Vessel strike, No.......... No............. No............. None identified.. Unk.............. 9.28 0.2
Strategic......... entanglement,
ocean noise,
marine debris,
oil spills and
contaminants,
climate change.

[[Page 20036]]

Dwarf sperm whale.............. Western North Not Listed... Not Depleted...... Unknown........... Small-Med. Income......... Fast...... Entanglement, No.......... No............. No............. None identified.. Increasing....... 57 Unk
Atlantic. Not Strategic..... vessel strike,
marine debris,
ocean noise,
hunting (Lesser
Antilles),
disease, climate
change.
Pygmy sperm whales............. Western North Not Listed... Not Depleted...... Unknown........... Small-Med. Income......... Fast...... Entanglement, No.......... No............. No............. None identified.. Increasing....... 57 Unk
Atlantic. Not Strategic..... vessel strike,
marine debris,
ocean noise,
hunting (Lesser
Antilles),
disease, climate
change.
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Unk = Unknown.

[[Page 20037]]

Sperm Whale (North Atlantic Stock), Dwarf Sperm Whale (Western North
Atlantic and Northern Gulf of America Stocks), Pygmy Sperm Whale
(Western North Atlantic and Northern Gulf of America Stocks)
Sperm whales are listed as endangered under the ESA and the North
Atlantic stock is considered depleted and strategic under the MMPA.
Neither dwarf sperm whale nor pygmy sperm whale is listed under the
ESA, and none of the stocks are considered depleted or strategic. The
stock abundances range from 510 (combined estimate for the Northern
Gulf of America stocks of dwarf and pygmy sperm whales from Navy's
NMSDD) to 5,895 for the North Atlantic stock of sperm whale. There are
no UMEs or other factors that cause particular concern for the stocks
in the Atlantic Ocean, and there are no known biologically important
areas for these stocks in the AFTT Study Area. These stocks face
several chronic anthropogenic and non-anthropogenic risk factors,
including entanglement and climate change, among others.
As shown in table 83, the maximum annual allowable instances of
take under this proposed rule by Level A Harassment and Level B
harassment range from 7 (North Atlantic stock of sperm whale) to 180
(Western North Atlantic stock of dwarf sperm whale) and 175 (Northern
Gulf of America stock of pygmy sperm whale) to 12,590 (North Atlantic
stock of sperm whale), respectively. As indicated, the rule also allows
for up to 2 takes by serious injury or mortality of North Atlantic
sperm whales over the course of the 7-year rule, the impacts of which
are discussed above in the Serious Injury and Mortality section. The
total take allowable for each stock across all 7 years of the rule is
indicated in table 49.
Regarding the potential takes associated with auditory impairment,
as described in the Auditory Injury from Sonar Acoustic Sources and
Explosives and Non-Auditory Injury from Explosives section above, any
takes in the form of TTS are expected to be lower-level, of short
duration (even the longest recovering in several hours or less than a
day), and mostly not in a frequency band that would be expected to
interfere with odontocete echolocation, overlap more than a relatively
narrow portion of the vocalization range of any single species or
stock, or preclude detection or interpretation of important low-
frequency cues. Any associated lost opportunities or capabilities
individuals might experience as a result of TTS would not be at a level
or duration that would be expected to impact reproductive success or
survival. For similar reasons, while auditory injury impacts last
longer, the low anticipated levels of AUD INJ that could be reasonably
expected to result from these activities are unlikely to have any
effect on fitness. The rule also allows for one take of North Atlantic
sperm whale by non-auditory injury (table 50). As described above,
given the small number of potential exposures and the anticipated
effectiveness of the mitigation measures in minimizing the pressure
levels to which any individuals are exposed, these injuries are
unlikely to impact reproduction or survival.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 178 dB SPL and last from a
few minutes to a few hours, at most, with associated responses most
likely in the form of moving away from the source, foraging
interruptions, vocalization changes, or disruption of other social
behaviors, lasting from a few minutes to several hours. Pygmy and dwarf
sperm whales are small-medium bodied income breeders with a fast pace
of life. They are generally more sensitive to missed foraging
opportunities, especially during lactation, but would be quick to
recover given their fast pace of life. Sperm whales are large-bodied
income breeders with a slow pace of life, and are likely more resilient
to missed foraging opportunities due to acoustic disturbance than
smaller odontocetes. However, they may be more susceptible to impacts
due to lost foraging opportunities during reproduction, especially if
they occur during lactation (Farmer et al., 2018). Further, as
described in the Group and Species-Specific Analyses section above and
the Proposed Mitigation Measures section, mitigation measures are
expected to further reduce the potential severity of impacts through
real-time operational measures that minimize higher level/longer
duration exposures and time/area measures that reduce impacts in high
value habitat.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In this case, given the
number of takes by harassment as compared to the stock/species
abundance (see table 83) and the fact that the majority of takes of the
Northern Gulf of America stock of pygmy and dwarf sperm whale occur in
the Gulf of America (95 and 96 percent, respectively), and the majority
of takes of the North Atlantic stock of sperm whale and Western North
Atlantic stock of pygmy and dwarf sperm whale occur in the mid-Atlantic
(80, 72, and 73 percent, respectively) it is likely that some portion
of the individuals taken are taken repeatedly over a small number of
days. However, given the variety of activity types that contribute to
take across separate exercises conducted at different times and in
different areas, and the fact that many result from transient
activities conducted at sea, it is unlikely that repeated takes would
occur either in numbers or clumped across sequential days in a manner
likely to impact foraging success and energetics or other behaviors
such that reproduction or survival are likely to be impacted. Further,
sperm whales are nomadic, and there are no known foraging areas or
other areas within which animals from any of these stocks are known to
congregate.
As analyzed and described in the Mortality section above, given the
status of the stock and in consideration of other ongoing human-caused
mortality, the M/SI proposed for authorization for the North Atlantic
stock of sperm whales (2 over the course of the 7-year rule, or 0.29
annually) would not, alone, be expected to adversely affect the stock
through rates of recruitment or survival. Given the magnitude and
severity of the take by harassment for each stock discussed above and
any anticipated habitat impacts, and in consideration of the required
mitigation measures and other information presented, the take by
harassment proposed for authorization is unlikely to result in impacts
on the reproduction or survival of any individuals and, thereby,
unlikely to affect annual rates of recruitment or survival of any of
these stocks either alone or, for the North Atlantic stock of sperm
whale, in combination with the M/SI proposed for authorization. Last,
we are aware that some Northern Gulf of America stocks have experienced
lower rates of reproduction and survival since the DWH oil spill,
however, those effects are reflected in the SARs and other data
considered in these analyses and do not change our findings. For these
reasons, we have determined that the take by harassment anticipated and
proposed for authorization would have a negligible impact on the North
Atlantic stock of sperm whale, Northern Gulf of America stocks of dwarf
and pygmy sperm whales, and Western

[[Page 20038]]

North Atlantic stocks of dwarf and pygmy sperm whales.
Sperm Whale (Northern Gulf of America stock)
Sperm whales are listed as endangered under the ESA and the
Northern Gulf of America stock is considered depleted and strategic
under the MMPA. The Navy's NMSDD estimates the stock abundance as 1,614
animals. Sperm whales aggregate at the mouth of the Mississippi River
and along the continental slope in or near cyclonic cold-core eddies
(counterclockwise water movements in the northern hemisphere with a
cold center) or anticyclone eddies (clockwise water movements in the
northern hemisphere) (Davis et al., 2007). Habitat models for sperm
whale occurrence indicate a high probability of suitable habitat along
the shelf break off the Mississippi delta, Desoto Canyon, and western
Florida (Best et al., 2012; Weller et al., 2000), and this area may be
important for feeding and reproduction (Baumgartner et al., 2001;
Jochens et al., 2008; NMFS, 2010), although the seasonality of breeding
in Northern Gulf of America stock of sperm whales is not known (Jochens
et al., 2008). This stock faces several chronic anthropogenic and non-
anthropogenic risk factors, including vessel strike, entanglement, oil
spills, and climate change, among others.
As shown in table 83, the maximum annual allowable instances of
take under this proposed rule by Level B harassment is 275. As
indicated, the rule also allows for up to 1 takes by serious injury or
mortality over the course of the 7-year rule, the impacts of which are
discussed above in the Serious Injury and Mortality section. No Level A
harassment (auditory or non-auditory injury) is proposed for
authorization. The total take allowable across all 7 years of the rule
is indicated in table 49.
Regarding the potential takes associated with TTS, as described in
the Temporary Threshold Shift section above, any takes in the form of
TTS are expected to be lower-level, of short duration (even the longest
recovering in several hours or less than a day), and mostly not in a
frequency band that would be expected to interfere with sperm whale
communication or other important low-frequency cues. Any associated
lost opportunities or capabilities individuals might experience as a
result of TTS would not be at a level or duration that would be
expected to impact reproductive success or survival.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 178 dB SPL and last from a
few minutes to a few hours, at most, with associated responses most
likely in the form of moving away from the source, foraging
interruptions, vocalization changes, or disruption of other social
behaviors, lasting from a few minutes to several hours. Sperm whales
are large-bodied income breeders with a slow pace of life, and are
likely more resilient to missed foraging opportunities due to acoustic
disturbance than smaller odontocetes. However, they may be more
susceptible to impacts due to lost foraging opportunities during
reproduction, especially if they occur during lactation (Farmer et al.,
2018).
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In this case, given the
lower number of takes by harassment as compared to the stock/species
abundance (see table 83), their migratory movement pattern, and the
absence of take concentrated in areas in which animals are known to
congregate, it is unlikely that any individual sperm whales would be
taken on more than a small number of days within a year and, therefore,
the anticipated behavioral disturbance is not expected to affect
reproduction or survival.
As analyzed and described in the Mortality section above, given the
status of the stock and in consideration of other ongoing human-caused
mortality, the M/SI proposed for authorization for the Northern Gulf of
America stock of sperm whales (one over the course of the 7-year rule,
or 0.14 annually) would not, alone, be expected to adversely affect the
stock through rates of recruitment or survival. Given the magnitude and
severity of the take by harassment discussed above and any anticipated
habitat impacts, and in consideration of the required mitigation
measures and other information presented, the take by harassment
proposed for authorization is unlikely to result in impacts on the
reproduction or survival of any individuals and, thereby, unlikely to
affect annual rates of recruitment or survival either alone or in
combination with the M/SI proposed for authorization. Last, we are
aware that some Northern Gulf of America stocks have experienced lower
rates of reproduction and survival since the DWH oil spill, however,
those effects are reflected in the SARs and other data considered in
these analyses and do not change our findings. For these reasons, we
have determined that the take anticipated and proposed for
authorization would have a negligible impact on the Northern Gulf of
America stock of sperm whales.
Beaked Whales--
This section builds on the broader odontocete discussion above
(i.e., that information applies to beaked whales as well), and brings
together the discussion of the different types and amounts of take that
different beaked whale species and stocks will likely incur, any
additional applicable mitigation, and the status of the species and
stocks to support the negligible impact determinations for each species
or stock.

Table 85--Annual Estimated Take by Level B Harassment, Level A Harassment, and Mortality and Related Information for Atlantic Stocks of Beaked Whales in the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum
Maximum Maximum annual take Season(s)
NMFS stock NMSDD annual annual Maximum Maximum as with 40 Region(s) with 40 percent
Marine mammal species Stock abundance abundance Level B Level A annual annual percentage percent of of take or greater
harassment harassment mortality take of stock take or
abundance greater
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Blainville's beaked whale.............. Northern Gulf of America.. 98 * 99 126 0 0 126 127 N/A Key West (64 percent).
Goose-beaked whale..................... Northern Gulf of America.. 18 * 368 460 0 0 460 125 N/A Key West (62 percent).
Gervais' beaked whale.................. Northern Gulf of America.. 20 * 386 125 0 0 125 32 N/A Key West (65 percent).
Blainville's beaked whale.............. Western North Atlantic.... * 2,936 1,279 25,705 1 0 25,706 876 N/A Mid-Atlantic (66
percent).

[[Page 20039]]

Goose-beaked whale..................... Western North Atlantic.... 4,260 * 4,901 112,070 2 0 112,072 2,287 N/A Mid-Atlantic (80
percent).
Gervais' beaked whale.................. Western North Atlantic.... * 8,595 991 25,446 1 0 25,447 296 N/A Mid-Atlantic (66
percent).
Northern bottlenose whale.............. Western North Atlantic.... * Unk 82 1,651 1 0 1,652 Unk N/A Northeast (47 percent)
Mid-Atlantic (52
percent).
Sowerby's beaked whale................. Western North Atlantic.... 492 * 1,279 25,622 1 0 25,623 2,003 N/A Mid-Atlantic (67
percent).
True's beaked whale.................... Western North Atlantic.... * 4,480 1,279 25,582 0 0 25,582 571 N/A Mid-Atlantic (68
percent).
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Unk = Unknown; N/A = Not Applicable. NMSDD abundances are averages only within the U.S. EEZ.
* Indicates which abundance estimate was used to calculate the maximum annual take as a percentage of abundance, either the NMFS SAR (Hayes et al., 2024) or the NMSDD (table 2.4-1 in appendix
A of the application). Please refer to the following section for details on which abundance estimate was selected.

[[Page 20040]]

Table 86--Life History Traits, Important Habitat, and Threats to Beaked Whales in the AFTT Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Annual
Body Reproductive Pace of Chronic risk UME, oil ESA- designated BIAs (Labrecque Other important mortality/
Marine mammal species Stock ESA status MMPA status Movement ecology size strategy life factors spill, other critical et al. 2015) habitat Population trend PBR serious
habitat injury
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Blainville's beaked whale...... Northern Gulf of Not Listed...... Not Depleted...... Nomadic-resident.. Med..... Mixed.......... Med....... Entanglement, N/A......... No............. No............. None identified.. Unk.............. 0.7 5.2
America. Not Strategic..... marine debris,
ocean noise,
energy
exploration and
development, oil
spills, climate
change.
Goose-beaked whale............. Northern Gulf of Not Listed...... Not Depleted...... Nomadic-resident.. Med..... Mixed.......... Med....... Ocean noise, N/A......... No............. No............. None identified.. Unk.............. 0.1 5.2
America. Not Strategic..... energy
exploration and
development, oil
spills, climate
change.
Gervais' beaked whale.......... Northern Gulf of Not Listed...... Not Depleted...... Nomadic-resident.. Med..... Mixed.......... Med....... Entanglement, N/A......... No............. No............. None identified.. Unk.............. 0.1 5.2
America. Not Strategic..... ocean noise,
energy
exploration and
development, oil
spills, climate
change.
Blainville's beaked whale...... Western North Not Listed...... Not Depleted...... Nomadic-resident.. Med..... Mixed.......... Med....... Entanglement, N/A......... No............. No............. None identified.. Unk.............. 24 0.2
Atlantic. Not Strategic..... marine debris,
ocean noise,
climate change.
Goose-beaked whale............. Western North Not Listed...... Not Depleted...... Nomadic-resident.. Med..... Mixed.......... Med....... Ocean noise, N/A......... No............. No............. Georges Bank and Unk, possibly 38 0.2
Atlantic. Not Strategic..... climate change. New England increasing.
Seamounts,
Canyons off New
Jersey and
Delmarva, Cape
Hatteras,
Southeast U.S..
Gervais' beaked whale.......... Western North Not Listed...... Not Depleted...... Nomadic-resident.. Med..... Mixed.......... Med....... Entanglement, N/A......... No............. No............. None identified.. Unk.............. 70 0
Atlantic. Not Strategic..... hunting, ocean
noise, climate
change.
Northern bottlenose whale...... Western North Not Listed...... Not Depleted...... Nomadic-resident.. Large... Mixed.......... Med....... Ocean noise, N/A......... No............. No............. None identified.. Unk.............. Unk 0
Atlantic. Not Strategic..... hunting, climate
change.
Sowerby's beaked whale......... Western North Not Listed...... Not Depleted...... Nomadic-resident.. Med..... Mixed.......... Med....... Ocean noise, N/A......... No............. No............. None identified.. Unk.............. 3.4 0
Atlantic. Not Strategic..... PCBs,
entanglement,
climate change.
True's beaked whale............ Western North Not Listed...... Not Depleted...... Nomadic-resident.. Med..... Mixed.......... Med....... Ocean noise, N/A......... No............. No............. None identified.. Unk, possibly 34 0.2
Atlantic. Not Strategic..... climate change. increasing.
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: N/A = Not Applicable; Und = Undetermined; Unk = Unknown.

[[Page 20041]]

Beaked Whales (Western North Atlantic Stocks)
These stocks are not listed as endangered or threatened under the
ESA, and they are not considered depleted or strategic under the MMPA.
The stock abundance estimates generally range from 1,279 (Sowerby's
beaked whale, NMSDD) to 8,595 (Gervais' beaked whale). The SAR states
that the abundance of Western North Atlantic northern bottlenose whale
is unknown, and the NMSDD estimates the stock abundance as 82 animals,
but reports that the estimate is from within the EEZ and is lower than
the overall population abundance given that the range of the stock
exceeds the EEZ boundary. See the Density Technical Report (U.S.
Department of the Navy, 2024) for additional information. There are no
UMEs or other factors that cause particular concern for this stock, and
there are no known biologically important areas for beaked whales in
the AFTT Study Area, though of note, these stocks generally occur in
higher densities year-round in deep waters over the Atlantic
continental shelf margins. The Western North Atlantic stocks of goose-
beaked whales and Blainville's beaked whales generally congregate over
continental shelf margins from Canada to North Carolina, with goose-
beaked whales reported as far south as the Caribbean and Blainville's
beaked whales as far south as the Bahamas. The Western North Atlantic
stock of Gervais' beaked whales generally congregate over continental
shelf margins from New York to North Carolina. The Western North
Atlantic stock of Sowerby's beaked whales is the most northerly
distributed stock of deep-diving mesoplodonts, and they generally
congregate over continental shelf margins from Labrador to
Massachusetts. The Western North Atlantic stock of True's beaked whales
generally congregate over continental shelf margins from Nova Scotia to
Cape Hatteras, with northern occurrence likely relating to the Gulf
Stream. The Western North Atlantic stock of Northern bottlenose whales
is uncommon in U.S. waters and generally congregates in areas of high
relief, including shelf breaks and submarine canyons from the Davis
Strait to New England, although strandings have occurred as far south
as North Carolina. Western North Atlantic beaked whales face several
chronic anthropogenic and non-anthropogenic risk factors, including
entanglement and climate change, among others.
As shown in table 85, the maximum annual allowable instances of
take under this proposed rule by Level A Harassment and Level B
harassment range from 0 to 2 and 1,651 to 112,070, respectively. No
mortality is anticipated or proposed for authorization, and nor is any
non-auditory injury. The total take allowable across all 7 years of the
rule is indicated in table 49.
Regarding the potential takes associated with auditory impairment
(for True's beaked whale, TTS only), as described in the Auditory
Injury from Sonar Acoustic Sources and Explosives and Non-Auditory
Injury from Explosives section above, any takes in the form of TTS are
expected to be lower-level, of short duration (from minutes to, at
most, several hours or less than a day), and mostly not in a frequency
band that would be expected to interfere with odontocete echolocation,
overlap more than a relatively narrow portion of the vocalization range
of any single species or stock, or preclude detection or interpretation
of important low-frequency cues. Any associated lost opportunities or
capabilities individuals might experience as a result of TTS would not
be at a level or duration that would be expected to impact reproductive
success or survival. For similar reasons, while auditory injury impacts
last longer, the low anticipated levels of AUD INJ that could be
reasonably expected to result from these activities (for all Western
North Atlantic beaked whales except True's beaked whales) are unlikely
to have any effect on fitness.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 154 dB SPL and last from a
few minutes to a few hours, at most, with associated responses most
likely in the form of moving away from the source, foraging
interruptions, vocalization changes, or disruption of other social
behaviors, lasting from a few minutes to several hours. Beaked whales
are medium-to-large-bodied odontocetes with a medium pace of life and
likely moderately resilient to missed foraging opportunities due to
acoustic disturbance. They are mixed breeders (i.e., behaviorally
income breeders), and they demonstrate capital breeding strategies
during gestation and lactation (Keen et al., 2021), so they may be more
vulnerable to prolonged loss of foraging opportunities during
gestation. Further, as described in the Group and Species-Specific
Analyses section above and the Proposed Mitigation Measures section,
mitigation measures are expected to further reduce the potential
severity of impacts through real-time operational measures that
minimize higher level/longer duration exposures and time/area measures
that reduce impacts in high value habitat.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In this case, given the
number of takes by harassment as compared to the stock/species
abundance (see table 85), it is likely that some portion of the
individuals taken are taken repeatedly over a small (Western North
Atlantic northern bottlenose whale and Gervais' beaked whale) to
moderate (all other stocks) number of days, with the exception of
Sowerby's beaked whales (discussed below). However, given the variety
of activity types that contribute to take across separate exercises
conducted at different times and in different areas, and the fact that
many result from transient activities conducted at sea, it is unlikely
that takes would occur clumped across sequential days in a manner
likely to impact foraging success and energetics or other behaviors
such that reproduction or survival are likely to be impacted. Further,
while there are several known high-density areas for goose-beaked
whales, around canyons, seamounts, and Cape Hatteras, which is common
for multiple species, there are no known foraging areas or other areas
within which animals are known to congregate for reproductive or other
important behaviors, and nor are the takes concentrated within a
specific region and season.
Regarding the magnitude of repeated takes for the Sowerby's beaked
whales, given the high number of takes by harassment as compared to the
stock abundance, it is more likely that some number of individuals
would experience a comparatively higher number of repeated takes over a
potentially fair number of sequential days. Due to the higher number of
repeated takes, it is more likely that a portion of the individuals
taken by harassment (approximately 50 percent of which would be female)
could be repeatedly interrupted during foraging in a manner and amount
such that impacts to the energy budgets of a small number of females
(from either losing feeding opportunities or expending considerable
energy moving away from sound sources or finding alternative feeding
options) could cause them to forego reproduction for a year (noting
that beaked whale calving intervals may be about 2 years) (New et al.,
2013)).

[[Page 20042]]

Energetic impacts to males are generally meaningless to population
rates unless they cause death, and it takes extreme energy deficits
beyond what would ever be likely to result from these activities to
cause the death of an adult marine mammal, male or female. While the
population trend of this stock is not known, it is not considered
depleted or strategic, and there are no known sources of human-caused
mortality indicated in the SARs. Importantly, the increase in a calving
interval by a year would have far less of an impact on a population
rate than a mortality would and, accordingly, a small number of
instances of foregone reproduction would not be expected to adversely
affect this stock through effects on annual rates of recruitment or
survival (noting also that no mortality is predicted or authorized for
this stock). The population trend of the Western North Atlantic stock
of goose-beaked whales is not known but possibly increasing, and, like
the Sowerby's beaked whale stock, it is not considered depleted or
strategic, and there are no known sources of human-caused mortality
indicated in the SARs. Importantly, the increase in a calving interval
by a year would have far less of an impact on a population rate than a
mortality would and, accordingly, a limited number of instances of
foregone reproduction would not be expected to adversely affect this
stock through effects on annual rates of recruitment or survival
(noting also that no mortality is predicted or authorized for this
stock).
Given the magnitude and severity of the take by harassment
discussed above and any anticipated habitat impacts, and in
consideration of the required mitigation measures and other information
presented, the Action Proponents' activities are unlikely to result in
impacts on the reproduction or survival of any individuals of the
Western North Atlantic stocks of beaked whales (Blainville's beaked
whale, goose-beaked whale, Gervais' beaked whale, northern bottlenose
dolphin, and True's beaked whale), with the exception of Sowerby's
beaked whales, and thereby unlikely to affect annual rates of
recruitment or survival. For Sowerby's beaked whales, as described
above, we do not anticipate the relatively small number of individuals
that might be taken over repeated days within the year in a manner that
results in a year of foregone reproduction to adversely affect either
stock through effects on rates of recruitment or survival, given the
statuses of these stocks. For these reasons, we have determined that
the total take (considering annual maxima and across seven years)
anticipated and proposed for authorization would have a negligible
impact on all Western North Atlantic beaked whales.
Beaked Whales (Northern Gulf of America Stocks)
These stocks are not listed as endangered or threatened under the
ESA, and they are not considered depleted or strategic under the MMPA.
The estimated abundances of these Blainville's beaked whale, goose-
beaked whale, and Gervais' beaked whale are 99, 368, and 386,
respectively, as indicated in the Navy's NMSDD estimates. There are no
known biologically important areas for beaked whales in the Gulf of
America. These stocks all occur year-round in deep water areas in the
Gulf of America and Key West. Beaked whales in the Gulf of America face
several chronic anthropogenic and non-anthropogenic risk factors,
including energy exploration and development, entanglement, and climate
change, among others.
As shown in table 85, the maximum annual allowable instances of
take under this proposed rule by Level B harassment is 126, 460, and
125 for Blainville's beaked whale, goose-beaked whale, and Gervais'
beaked whale, respectively. No mortality is anticipated or proposed for
authorization, and nor is any auditory or non-auditory injury (Level A
harassment). The total take allowable across all 7 years of the rule is
indicated in table 49.
Regarding the potential takes associated with TTS, as described in
the Temporary Threshold Shift section above, any takes in the form of
TTS are expected to be lower-level, of short duration (from minutes to,
at most, several hours or less than a day), and mostly not in a
frequency band that would be expected to interfere with odontocete
echolocation, overlap more than a relatively narrow portion of the
vocalization range of any single species or stock, or preclude
detection or interpretation of important low-frequency cues. Any
associated lost opportunities or capabilities individuals might
experience as a result of TTS would not be at a level or duration that
would be expected to impact reproductive success or survival.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 154 dB SPL and last from a
few minutes to a few hours, at most, with associated responses most
likely in the form of moving away from the source, foraging
interruptions, vocalization changes, or disruption of other social
behaviors, lasting from a few minutes to several hours. Beaked whales
are medium-bodied odontocetes with a medium pace of life and likely
moderately resilient to missed foraging opportunities due to acoustic
disturbance. They are mixed breeders (i.e., behaviorally income
breeders) and they demonstrate capital breeding strategies during
gestation and lactation (Keen et al., 2021), so they may be more
vulnerable to prolonged loss of foraging opportunities during
gestation.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In this case, given the
number of takes by harassment as compared to the stock/species
abundances (see table 85) and the fact that 60-65 percent of the takes
occur around Key West, it is likely that some portion of the
individuals taken are taken repeatedly over a small number of days.
However, given the variety of activity types that contribute to take
across separate exercises conducted at different times and in different
areas, and the fact that many result from transient activities
conducted at sea, it is unlikely that repeated takes would occur either
in numbers or clumped across sequential days in a manner likely to
impact foraging success and energetics or other behaviors such that
reproduction or survival are likely to be impacted.
Given the magnitude and severity of the impacts discussed above to
Northern Gulf of America stocks of beaked whales (considering annual
take maxima and the total across 7 years) and their habitat, and in
consideration of the other information presented, the Action
Proponents' activities are unlikely to result in impacts on the
reproduction or survival of any individuals and, thereby, unlikely to
affect annual rates of recruitment or survival. Last, we are aware that
some Northern Gulf of America stocks of beaked whales have experienced
lower rates of reproduction and survival since the DWH oil spill,
however, those effects are reflected in the SARs and other data
considered in these analyses and do not change our findings. For these
reasons, we have determined that the take by harassment anticipated and
proposed for authorization would have a negligible impact on the
Northern Gulf of America stocks of beaked whales.

[[Page 20043]]

Dolphins and Small Whales--
Of the 53 stocks of dolphins and small whales (Delphinidae) for
which incidental take is proposed for authorization (see table 87),
none are listed as endangered or threatened under the ESA. Only spinner
dolphins are listed as depleted under the MMPA, however, about a third
of the species are listed as strategic, including 14 stocks of
bottlenose dolphins, Northern Gulf of America stocks of Clymene,
striped, and spinner dolphins, and the Western Northern Atlantic stocks
of spinner dolphins and short-finned pilot whales. As shown in table 87
and table 88, these Delphinids vary in stock abundance, body size, and
movement ecology from, for example, the small-bodied, nomadic/migratory
Western North Atlantic white-beaked dolphins that range well beyond the
U.S. EEZ and outside the AFTT Study Area and have a SAR abundance over
500,000, to the medium-sized resident Bay stocks of bottlenose dolphins
with abundances under 200, to the large-bodied nomadic Western North
Atlantic killer whale, for which the abundance is unknown. While there
are several small and resident populations of bottlenose dolphins,
there are no other known biologically important areas (e.g., foraging,
reproduction) for any of these Delphinid stocks. Delphinids face a
number of chronic anthropogenic and non-anthropogenic risk factors
including biotoxins, chemical contaminants, fishery interaction,
habitat alteration, illegal feeding/harassment, ocean noise, oil spills
and energy exploration, vessel strikes, disease, climate change, the
impacts of which vary depending whether the stock is more coastal
(e.g., biotoxins and some fishing interactions more seen in bottlenose
dolphins), more or less deep-diving (e.g., entanglement more common in
deep divers like pygmy killer whales and pilot whales), in the Gulf of
America (e.g., lingering lower reproductive rates for some stocks
affected by DWH oil spill impacts), and other behavioral differences
(e.g., vessels strikes more concern for killer whales).

[[Page 20044]]

Table 87--Annual Estimated Take by Level B Harassment, Level A Harassment, and Mortality and Related Information for Dolphins in the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum
annual Greatest degree
Maximum Maximum Maximum Maximum harassment Season(s) with 40 Region(s) with 40 any individual
Marine mammal species Stock NMFS stock NMSDD annual annual annual annual as percent of take percent of take expected to be
abundance abundance Level B Level A mortality take percentage or greater or greater taken repeatedly
harassment harassment of stock across multiple
abundance days
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Atlantic spotted dolphin....... Northern Gulf of * 21,506 11,476 12,804 20 0 12,824 60 N/A.............. Gulf of America Zero to small
America. (100 percent). number of days.
Bottlenose dolphin............. Gulf of America * 16,407 13,382 80 0 0 80 0 N/A.............. Gulf of America Zero to small
Eastern Coastal. (63 percent). number of days.
Bottlenose dolphin............. Gulf of America * 11,543 7,031 7,146 17 0 7,163 62 N/A.............. Gulf of America Zero to small
Northern Coastal. (100 percent). number of days.
Bottlenose dolphin............. Northern Gulf of 7,462 * 21,997 6,274 4 0 6,278 29 N/A.............. Gulf of America Zero to small
America Oceanic. (70 percent). number of days.
Bottlenose dolphin............. Gulf of America 20,759 * 26,100 3,331 1 0 3,332 13 N/A.............. Gulf of America Zero to small
Western Coastal. (100 percent). number of days.
Bottlenose dolphin............. Mississippi 1,265 * 1,057 1,758 1 0 1,759 166 N/A.............. Gulf of America Small number of
Sound, Lake (100 percent). days.
Borgne, Bay
Boudreau.
Bottlenose dolphin............. Northern Gulf of 63,280 * 109,059 71,331 29 0 71,360 65 N/A.............. Gulf of America Zero to small
America (100 percent). number of days.
Continental
Shelf.
Bottlenose dolphin............. Nueces Bay/Corpus 58 * 41 4 0 0 4 10 N/A.............. Gulf of America Zero to small
Christi Bay. (100 percent). number of days.
Bottlenose dolphin............. Sabine Lake...... 122 * 148 1 0 0 1 1 N/A.............. Gulf of America Zero to small
(100 percent). number of days.
Bottlenose dolphin............. St. Andrew Bay... * 199 114 46 0 0 46 23 N/A.............. Gulf of America Small number of
(100 percent). days.
Bottlenose dolphin............. St. Joseph Bay... * 142 34 42 0 0 42 30 N/A.............. Gulf of America Small number of
(100 percent). days.
Bottlenose dolphin............. Tampa Bay........ Unk * 599 350 0 0 350 58 N/A.............. Gulf of America Small number of
(100 percent). days.
Clymene dolphin................ Northern Gulf of 513 * 3,126 599 3 0 602 19 N/A.............. Gulf of America Zero to small
America. (85 percent). number of days.
False killer whale............. Northern Gulf of 494 * 1,023 230 0 0 230 22 N/A.............. Gulf of America Zero to small
America. (84 percent). number of days.
Fraser's dolphin............... Northern Gulf of 213 * 1,081 241 0 0 241 22 N/A.............. Gulf of America Zero to small
America. (76 percent). number of days.
Killer whale................... Northern Gulf of 267 * 511 110 0 0 110 22 N/A.............. Gulf of America Zero to small
America. (85 percent). number of days.
Melon-headed whale............. Northern Gulf of 1,749 * 3,579 771 1 0 772 22 N/A.............. Gulf of America Zero to small
America. (84 percent). number of days.
Pygmy killer whale............. Northern Gulf of 613 * 1,278 285 0 0 285 22 N/A.............. Gulf of America Zero to small
America. (85 percent). number of days.
Risso's dolphin................ Northern Gulf of * 1,974 813 203 0 0 203 10 N/A.............. Gulf of America Zero to small
America. (72 percent). number of days.
Rough-toothed dolphin.......... Northern Gulf of Unk * 3.452 1,642 3 0 1,645 48 N/A.............. Gulf of America Small number of
America. (92 percent). days.
Short-finned pilot whale....... Northern Gulf of 1,321 * 1,835 1,021 3 0 1,024 56 N/A.............. Gulf of America Small number of
America. (90 percent). days.
Striped dolphin................ Northern Gulf of 1,817 * 7,782 2,376 7 0.29 2,384 31 Winter (40 Gulf of America Zero to small
America. percent). (70 percent). number of days.
Pantropical spotted dolphin.... Northern Gulf of * 37,195 35,057 6,316 9 0.71 6,327 17 N/A.............. Gulf of America Zero to small
America. (71 percent). number of days.
Spinner dolphin................ Northern Gulf of * 2,991 1,422 656 0 0 656 22 N/A.............. Gulf of America Zero to small
America. (99 percent). number of days.
Atlantic white-sided dolphin... Western North * 93,233 14,869 22,094 32 0 22,126 36 N/A.............. Northeast (69 Zero to small
Atlantic. percent) Mid- number of days.
Atlantic (31
percent).
Common dolphin................. Western North * 93,100 73,015 25,792 6 0 25,798 0 Winter (45 Mid-Atlantic (75 Small to moderate
Atlantic. percent). percent). number of days.

[[Page 20045]]

Atlantic spotted dolphin....... Western North * 31,506 28,226 120,798 87 0 120,885 384 N/A.............. Mid-Atlantic (59 Small to moderate
Atlantic. percent). number of days.
Bottlenose dolphin............. Indian River * 1,032 484 1,576 0 0 1,576 153 Fall (43 percent) Southeast (100 Small number of
Lagoon Estuarine percent). days.
System.
Bottlenose dolphin............. Jacksonville Unk 19 360 0 0 360 Und Fall (45 percent) Southeast (100 Moderate number
Estuarine System. percent). of days.
Bottlenose dolphin............. Northern Georgia/ Unk 19 2 0 0 2 Und N/A.............. Southeast (100 Zero to small
Southern South percent). number of days.
Carolina
Estuarine System.
Bottlenose dolphin............. Northern North 823 * 1,227 10,532 6 0 10,538 859 Summer (98 Mid-Atlantic (100 High number of
Carolina percent). percent). days.
Estuarine System.
Bottlenose dolphin............. Southern Georgia Unk * 619 123 1 0 124 20 N/A.............. Southeast (100 Small number of
Estuarine System. percent). days.
Bottlenose dolphin............. Southern North Unk * 486 162 0 0 162 33 Fall (60 percent) Mid-Atlantic (99 Small number of
Carolina percent). days.
Estuarine System.
Tamanend's Bottlenose Dolphin.. Western North 2,541 * 7,063 10,494 3 0 10,497 149 N/A.............. Southeast (100 Small number of
Atlantic, percent). days.
Central Florida
Coastal.
Tamanend's Bottlenose Dolphin.. Western North * 3,619 2,598 21,385 5 0 21,390 591 N/A.............. Southeast (100 Moderate number
Atlantic, percent). of days.
Northern Florida
Coastal.
Bottlenose dolphin............. Western North 6,639 * 10,325 73,720 60 0 73,780 715 N/A.............. Mid-Atlantic (100 Moderate number
Atlantic percent). of days.
Northern
Migratory
Coastal.
Bottlenose dolphin............. Western North 64,587 * 150,704 187,046 103 0.29 187,151 124 N/A.............. Mid-Atlantic (60 Small number of
Atlantic percent). days.
Offshore.
Tamanend's Bottlenose Dolphin.. Western North * 9,121 4,105 4,960 6 0.14 4,967 54 N/A.............. Southeast (95 Zero to small
Atlantic South percent). number of days.
Carolina/Georgia
Coastal.
Bottlenose dolphin............. Western North 3,751 * 7,911 10,180 9 0 10,189 1,549 N/A.............. Mid-Atlantic (60 Small number of
Atlantic percent) days.
Southern Southeast (40
Migratory percent).
Coastal.
Clymene dolphin................ Western North * 21,778 8,573 132,723 104 0.43 132,828 44 N/A.............. Mid-Atlantic (98 Moderate number
Atlantic. percent). of days.
False killer whale............. Western North * 1,298 97 572 1 0 573 Und Winter (40 Mid-Atlantic (48 Zero to small
Atlantic. percent). percent). number of days.
Fraser's dolphin............... Western North Unk * 518 2,905 3 0 2,908 561 N/A.............. Southeast (52 Moderate number
Atlantic. percent). of days.
Killer whale................... Western North Unk * 51 180 1 0 181 355 N/A.............. Mid-Atlantic (61 Small to moderate
Atlantic. percent). number of days.
Long-finned pilot whale........ Western North * 39,215 5,392 21,680 12 0 21,692 55 N/A.............. Mid-Atlantic (84 Zero to small
Atlantic. percent). number of days.
Melon-headed whale............. Western North Unk * 495 4,598 3 0 4,601 929 N/A.............. Southeast (43 Moderate number
Atlantic. percent). of days.
Pantropical spotted dolphin.... Western North * 2,757 1,147 13,068 5 0 13,073 474 N/A.............. High Seas (54 Moderate number
Atlantic. percent). of days.
Pygmy killer whale............. Western North Unk * 54 477 1 0 478 885 N/A.............. Southeast (45 Moderate number
Atlantic. percent). of days.
Risso's dolphin................ Western North * 44,067 12,845 37,239 25 0 37,264 85 N/A.............. Mid-Atlantic (40 Zero to small
Atlantic. percent). number of days.
Rough-toothed dolphin.......... Western North Unk * 824 4,753 6 0 4,759 578 N/A.............. Southeast (55 Moderate number
Atlantic. percent). of days.
Short-finned pilot whale....... Western North * 18,726 6,235 33,035 15 0 33,050 176 N/A.............. Mid-Atlantic (54 Small number of
Atlantic. percent). days.
Spinner dolphin................ Western North * 3,181 646 5,356 2 0 5,358 168 Winter (40 N/A.............. Small number of
Atlantic. percent). days.
Striped dolphin................ Western North * 48,274 43,044 208,802 163 0 208,965 433 N/A.............. Mid-Atlantic (89 Small to moderate
Atlantic. percent). number of days.
White-beaked dolphin........... Western North * 536,016 44 16 0 0 16 0 N/A.............. Northeast (92 Zero to small
Atlantic. percent). number of days.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Unk = Unknown; N/A = Not Applicable. NMSDD abundances are averages only within the U.S. EEZ.
* Indicates which abundance estimate was used to calculate the maximum annual take as a percentage of abundance, either the NMFS SAR (Hayes et al., 2024) or the NMSDD (table 2.4-1 in appendix
A of the application). Please refer to the following section for details on which abundance estimate was selected.

[[Page 20046]]

Table 88--Life History Traits, Important Habitat, and Threats to Dolphins in the AFTT Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Annual
Reproductive Pace of Chronic risk UME, oil ESA- designated BIAs (Labrecque Other important mortality/
Marine mammal species Stock ESA status MMPA status Movement ecology Body size strategy life factors spill, other critical et al. 2015) habitat Population trend PBR serious
habitat injury
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Atlantic spotted dolphin....... Northern Gulf of Not Listed. Not Depleted...... Migratory......... Small...... Income.......... Med....... Entanglement, No.......... No............. No............. None identified.. Unk.............. 166 36
America. Not Strategic..... fishery
interaction,
ocean noise,
illegal feeding/
harassment,
energy
exploration and
development, oil
spills, climate
change.
Bottlenose dolphin............. Gulf of America Not Listed. Not Depleted...... Nomadic-resident.. Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. None identified.. Unk, potentially 114 9.2
Eastern Coastal. Not Strategic..... chemical increasing.
contaminants,
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Bottlenose dolphin............. Gulf of America Not Listed. Not Depleted...... Nomadic-resident.. Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. None identified.. Unk, potentially 89 28
Northern Coastal. Not Strategic..... chemical increasing.
contaminants,
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Bottlenose dolphin............. Northern Gulf of Not Listed. Not Depleted...... Nomadic- resident. Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. None identified.. Stable........... 58 32
America Oceanic. Not Strategic..... chemical
contaminants,
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.

[[Page 20047]]

Bottlenose dolphin............. Gulf of America Not Listed. Not Depleted...... Nomadic- resident. Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. None identified.. Unk, potentially 167 36
Western Coastal. Not Strategic..... chemical stable.
contaminants,
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Bottlenose dolphin............. Mississippi Sound, Not Listed. Not Depleted...... Resident.......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. Mississippi Sound Unk, potentially 8.5 59
Lake Borgne, Bay Strategic......... chemical and associated stable.
Boudreau. contaminants, waters \a\.
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Bottlenose dolphin............. Northern Gulf of Not Listed. Not Depleted...... Nomadic-resident.. Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. None identified.. Unk, potentially 556 65
America Not Strategic..... chemical increasing.
Continental Shelf. contaminants,
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Bottlenose dolphin............. Nueces Bay/Corpus Not Listed. Not Depleted...... Resident.......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. Nueces Bay/Corpus Unk (insufficient Und 0.2
Christi Bay. Strategic......... chemical Christi Bay, data).
contaminants, Corpus Christi/
fishery Aransas Pass \b\.
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.

[[Page 20048]]

Bottlenose dolphin............. Sabine Lake....... Not Listed. Not Depleted...... Resident.......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. Sabine Pass Unk (insufficient 0.9 0
Not Strategic..... chemical Channel, lower data).
contaminants, Sabine Lake
fishery south of Blue
interaction, Buck Point,
habitat areal shipping
alteration, channels \c\.
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Bottlenose dolphin............. St. Andrew Bay.... Not Listed. Not Depleted...... Resident.......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. St. Andrew Bay, Unk (insufficient 1.5 0.2
Not Strategic..... chemical West Bay, East data).
contaminants, Bay, and North
fishery Bay \d\.
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Bottlenose dolphin............. St. Joseph Bay.... Not Listed. Not Depleted...... Resident.......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. St. Joseph Bay, Stable........... 1 Unk
Not Strategic..... chemical Crooked Island
contaminants, Sound \e\.
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.

[[Page 20049]]

Bottlenose dolphin............. Tampa Bay......... Not Listed. Not Depleted...... Nomadic-resident.. Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. Tampa Bay \f\.... Unk (Insufficient Und 3
Strategic......... chemical data).
contaminants,
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Clymene dolphin................ Northern Gulf of Not Listed. Not Depleted...... Nomadic........... Small...... Income.......... Fast...... Fishery No.......... No............. No............. None identified.. Likely increasing 2.5 8.4
America. Strategic......... interaction,
Deepwater
horizon, energy
exploration and
development, oil
spills, climate
change.
False killer whale............. Northern Gulf of Not Listed. Not Depleted...... Resident- nomadic. Med........ Income.......... Med....... Fishery No.......... No............. No............. None identified.. Decreasing....... 2.8 2.2
America. Not Strategic..... interaction,
contaminants,
hunting,
Deepwater
Horizon and
other oil
spills, disease,
climate change.
Fraser's dolphin............... Northern Gulf of Not Listed. Not Depleted...... Resident- nomadic. Small...... Income.......... Fast...... Fishery No.......... No............. No............. None identified.. Unk.............. 1 Unk
America. Not Strategic..... interaction,
energy
exploration and
development, oil
spills, climate
change.
Killer whale................... Northern Gulf of Not Listed. Not Depleted...... Resident.......... Large...... Income.......... Slow...... Chemical No.......... No............. No............. None identified.. Unk.............. 1.5 Unk
America. Not Strategic..... contaminants,
vessel traffic
and noise,
entanglement,
oil spills,
energy
exploration and
development,
climate change.
Melon-headed whale............. Northern Gulf of Not Listed. Not Depleted...... Resident- nomadic. Small...... Income.......... Med....... Fishery No.......... No............. No............. None identified.. Unk.............. 10 9.5
America. Not Strategic..... interaction,
ocean noise,
pollution,
energy
exploration and
development, oil
spills, climate
change.
Pygmy killer whale............. Northern Gulf of Not Listed. Not Depleted...... Resident-nomadic.. Small...... Income.......... Med....... Entanglement, No.......... No............. No............. None identified.. Unk.............. 2.8 1.6
America. Not Strategic..... ocean noise, oil
spill, oil and
gas exploration,
climate change.

[[Page 20050]]

Risso's dolphin................ Northern Gulf of Not Listed. Not Depleted...... Resident-nomadic.. Small-Med.. Income.......... Med....... Entanglement, No.......... No............. No............. None identified.. Unk (Insufficient 14 5.3
America. Not Strategic..... environmental data).
contamination,
hunting, ocean
noise, energy
exploration and
development, oil
spills, climate
change.
Rough-toothed dolphin.......... Northern Gulf of Not Listed. Not Depleted...... Resident-nomadic.. Small...... Income.......... Med....... Entanglement, No.......... No............. No............. None identified.. Unk.............. Und 39
America. Not Strategic..... ocean noise,
energy
exploration and
development, oil
spills, climate
change.
Short-finned pilot whale....... Northern Gulf of Not Listed. Not Depleted...... Resident.......... Med........ Income.......... Slow...... Entanglement, No.......... No............. No............. None identified.. Unk.............. 7.5 3.9
America. Not Strategic..... fishery
interaction,
vessel strikes,
energy
exploration and
development, oil
spills, climate
change.
Striped dolphin................ Northern Gulf of Not Listed. Not Depleted...... Nomadic........... Small...... Income.......... Med....... Entanglement, No.......... No............. No............. None identified.. Unk.............. 12 13
America. Strategic......... energy
exploration and
development, oil
spills, disease,
climate change.
Pantropical spotted dolphin.... Northern Gulf of Not Listed. Not Depleted...... Nomadic........... Small...... Income.......... Med....... Fishery No.......... No............. No............. None identified.. Unk (Insufficient Unk 0
America. Not Strategic..... interaction, data).
ocean noise,
pollution,
climate change.
Spinner dolphin................ Northern Gulf of Not Listed. Not Depleted...... Nomadic........... Small...... Income.......... Med....... Entanglement, No.......... No............. No............. None identified.. Stable, 19 0
America. Strategic......... Illegal feeding/ potentially
harassment, increasing.
climate change.
Atlantic white-sided dolphin... Western North Not Listed. Not Depleted...... Nomadic........... Small...... Income.......... Fast...... Entanglement, No.......... No............. No............. None identified.. Unk.............. 544 28
Atlantic. Not Strategic..... ocean noise,
fishery
interaction,
hunting
(Newfoundland,
Canada,
Greenland),
climate change.
Common dolphin................. Western North Not Listed. Not Depleted...... Nomadic........... Small...... Income.......... Med....... Entanglement, No.......... No............. No............. None identified.. Unk.............. 1,452 414
Atlantic. Not Strategic..... climate change.
Atlantic spotted dolphin....... Western North Not Listed. Not Depleted...... Unk, likely Small...... Income.......... Med....... Entanglement, No.......... No............. No............. None identified.. Decreasing....... 250 0
Atlantic. Not Strategic..... nomadic. ocean noise,
illegal feeding/
harassment,
climate change.

[[Page 20051]]

Bottlenose dolphin............. Indian River Not Listed. Not Depleted...... Resident.......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. Indian River Unk (insufficient 10 5.7
Lagoon Estuarine Strategic......... chemical Lagoon Estuarine data).
System. contaminants, System \g\.
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Bottlenose dolphin............. Jacksonville Not Listed. Not Depleted...... Resident.......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. Yes: Small and Jacksonville Unk (insufficient Unk 2
Estuarine System. Strategic......... chemical resident Estuarine System data).
contaminants, population. \h\.
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Bottlenose dolphin............. Northern Georgia/ Not Listed. Not Depleted...... Resident.......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. St. Helena Sound, Unk (insufficient Unk 59
Southern South Strategic......... chemical South Carolina data).
Carolina contaminants, to Ossabaw
Estuarine System. fishery Sound, Georgia
interaction, \i\.
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Bottlenose dolphin............. Northern North Not Listed. Not Depleted...... Resident.......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. Yes: Small and Northern North Unk (potentially 7.8 7.2-30
Carolina Strategic......... chemical resident Carolina stable).
Estuarine System. contaminants, population. Estuarine System
fishery \j\.
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.

[[Page 20052]]

Bottlenose dolphin............. Southern Georgia Not Listed. Not Depleted...... Resident.......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. Yes: Small and Southern Georgia Unk (insufficient Und 0.1
Estuarine System. Not Strategic..... chemical resident Estuarine System data).
contaminants, population. \k\.
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Bottlenose dolphin............. Southern North Not Listed. Not Depleted...... Resident.......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. Yes: Small and Southern North Unk.............. Und 0.4
Carolina Strategic......... chemical resident Carolina
Estuarine System. contaminants, population. Estuarine System
fishery \l\.
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Tamanend's Bottlenose Dolphin.. Western North Not Listed. Not Depleted...... Nomadic........... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. None identified.. Unk (insufficient 18 0.2
Atlantic, Central Strategic......... chemical data).
Florida Coastal. contaminants,
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.

[[Page 20053]]

Tamanend's Bottlenose Dolphin.. Western North Not Listed. Not Depleted...... Nomadic........... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. None identified.. Unk (insufficient 27 0.2
Atlantic, Strategic......... chemical data).
Northern Florida contaminants,
Coastal. fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Bottlenose dolphin............. Western North Not Listed. Not Depleted...... Migratory......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. None identified.. Decreasing....... 48 12.2-21.5
Atlantic Northern Strategic......... chemical
Migratory Coastal. contaminants,
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Bottlenose dolphin............. Western North Not Listed. Not Depleted...... Migratory......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. None identified.. Stable, 507 28
Atlantic Offshore. Not Strategic..... chemical potentially
contaminants, decreasing.
fishery
interaction,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Tamanend's Bottlenose Dolphin.. Western North Not Listed. Not Depleted...... Migratory......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. None identified.. Unk (insufficient 73 0.2-0.6
Atlantic South Strategic......... chemical data).
Carolina/Georgia contaminants,
Coastal. fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.

[[Page 20054]]

Bottlenose dolphin............. Western North Not Listed. Not Depleted...... Migratory......... Small-Med.. Income.......... Med....... Biotoxins, No.......... No............. No............. None identified.. Decreasing....... 24 0-18.3
Atlantic Southern Strategic......... chemical
Migratory Coastal. contaminants,
fishery
interaction,
habitat
alteration,
illegal feeding/
harassment,
ocean noise, oil
spills and
energy
exploration,
vessel strikes,
disease, climate
change.
Clymene dolphin................ Western North Not Listed. Not Depleted...... Nomadic........... Small...... Income.......... Fast...... Entanglement, No.......... No............. No............. None identified.. Unk.............. 126 0
Atlantic. Not Strategic..... fishery
interaction,
ocean noise,
PCBs, hunting
(Caribbean),
climate change.
False killer whale............. Western North Not Listed. Not Depleted...... Nomadic........... Med........ Income.......... Med....... Fishery No.......... No............. No............. None identified.. Unk (Insufficient 7.6 0
Atlantic. Not Strategic..... interaction, data).
contaminants,
hunting,
disease, climate
change.
Fraser's dolphin............... Western North Not Listed. Not Depleted...... Nomadic........... Small...... Income.......... Fast...... Fishery No.......... No............. No............. None identified.. Unk.............. Unk 0
Atlantic. Not Strategic..... interaction,
climate change.
Killer whale................... Western North Not Listed. Not Depleted...... Nomadic........... Large...... Income.......... Slow...... Chemical No.......... No............. No............. None identified.. Unk.............. Unk 0
Atlantic. Not Strategic..... contaminants,
vessel traffic
and noise,
entanglement,
oil spills,
climate change.
Long-finned pilot whale........ Western North Not Listed. Not Depleted...... Nomadic........... Med........ Income.......... Slow...... Entanglements, No.......... No............. No............. None identified.. Unk.............. 306 5.7
Atlantic. Not Strategic..... contaminants,
ocean noise,
disease, climate
change.
Melon-headed whale............. Western North Not Listed. Not Depleted...... Nomadic........... Small...... Income.......... Med....... Fishery No.......... No............. No............. None identified.. Unk (Insufficient Unk 0
Atlantic. Not Strategic..... interaction, data).
ocean noise,
pollution,
climate change.
Pantropical spotted dolphin.... Western North Not Listed. Depleted.......... Nomadic........... Small...... Income.......... Med....... Entanglement, No.......... No............. No............. None identified.. Stable, 19 0
Atlantic. Not Strategic..... Illegal feeding/ potentially
harassment, increasing.
climate change.
Pygmy killer whale............. Western North Not Listed. Not Depleted...... Nomadic........... Small...... Income.......... Med....... Entanglement, No.......... No............. No............. None identified.. Unk (Insufficient Unk 0
Atlantic. Not Strategic..... ocean noise, data).
climate change.

[[Page 20055]]

Risso's dolphin................ Western North Not Listed. Not Depleted...... Nomadic........... Small-Med.. Income.......... Med....... Entanglement, No.......... No............. No............. None identified.. Unk (Insufficient 307 18
Atlantic. Not Strategic..... environmental data).
contamination,
hunting, ocean
noise, climate
change.
Rough-toothed dolphin.......... Western North Not Listed. Not Depleted...... Nomadic........... Small...... Income.......... Med....... Entanglement, No.......... No............. No............. None identified.. Unk (Insufficient Und 0
Atlantic. Not Strategic..... ocean noise, data).
climate change.
Short-finned pilot whale....... Western North Not Listed. Not Depleted...... Resident-nomadic.. Med........ Income.......... Slow...... Entanglement, No.......... No............. No............. Mid-Atlantic Stable........... 143 218
Atlantic. Strategic......... fishery Bight Canyons
interaction, \m\.
vessel strikes,
climate change.
Spinner dolphin................ Western North Not Listed. Depleted.......... Nomadic........... Small...... Income.......... Fast...... Marine debris, No.......... No............. No............. None identified.. Unk.............. 19 0
Atlantic. Not Strategic..... ocean noise,
disease.
Striped dolphin................ Western North Not Listed. Not Depleted...... Nomadic........... Small...... Income.......... Med....... Entanglement, No.......... No............. No............. None identified.. Unk.............. 529 0
Atlantic. Not Strategic..... disease, climate
change.
White-beaked dolphin........... Western North Not Listed. Not Depleted...... Nomadic-migratory. Small...... Income.......... Fast...... Entanglement, No.......... No............. No............. None identified.. Unk.............. 4,153 0
Atlantic. Not Strategic..... climate change.
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Unk = Unknown, Und = Undetermined.
\a\ See Hubard et al. (2004), Mackey (2010), Arick et al. (2024), McBride (2013), Miller et al. (2013), Mullin et al. (2017), and Vollmer et al. (2021) for more information.
\b\ See Ronje et al. (2022), Shane (1980, Weller (1998), and W[uuml]rsig et al. (2022) for more information.
\c\ See Ronje et al. (2020), Ronje et al. (2021), Ronje et al. (2022), Wells (2014), and W[uuml]rsig et al. (2022) for more information.
\d\ See Balmer et al. (2008), Balmer et al. (2010), Balmer et al. (2018), Balmer et al. (2019a), Balmer et al. (2019b), Blaylock and Hoggard (1994), Bouveroux et al. (2014), Colborn (1999), Hayes et al. (2020), Kendall et al. (1997), Pollock (1982), Pollock et al. (1990),
Powell et al. (2018), Samuels and Bejder (2004), and Samuels and Spradlin (1995) for more information.
\e\ See Balmer et al. (2008), Balmer et al. (2010), Balmer et al. (2016), Balmer et al. (2018), Balmer et al. (2019a), Balmer et al. (2019b), Bouveroux et al. (2014), Burnham and Overton (1978), Burnham and Overton (1979), Chapman (1951), Cush (2016), Cush et al. (2019),
Darroch (1958), Hayes et al. (2020), Hubard et al. (2004), Kendall et al. (1997), Rosel et al. (2011), Schwacke et al (2010), and Toms (2019) for more information.
\f\ See Bassos (1993), Bassos-Hull et al. (2013), Boyd et al. (2021), Duffield and Wells (2002), Irvine and Wells (1972), Irvine et al. (1981), Leatherwood and Show (1980), Mate et al. (1995), McCallister (2011), Odell and Reynolds (1980), Scott et al. (1989), Sellas et
al. (2005), Simard et al. (2011), Thompson (1981), Urian et al. (2009), van Ginkel et al. (2018), Weigle (1990), Wells (1986), Wells (2014), Wells et al. (1998), Wells et al. (1996), Wells et al. (1987), and Wells et al. (2013) for more information.
\g\ See Durden et al. (2017), Durden et al. (2021), Odell and Asper (1990), Mazzoil et al. (2005), Mazzoil et al. (2008a), Mazzoil et al. (2008b), and Mazzoil et al. (2020) for more information.
\h\ See Caldwell (2001), and Mazzoil et al. (2020) for more information.
\i\ See Gubbins (2000a), Gubbins (2000b), Gubbins (2000c), and Waring et al. (2014) for more information.
\j\ See Garrison et al. (2017) and Gorgone et al. (2014) for more information.
\k\ See Pulster and Maruya (2008) and Balmer et al. (2013) for more information.
\l\ See Urian et al. (1999), Read et al. (2003), Waring et al. (2014), and Silva et al. (2020) for more information.
\m\ See Thorne et al. (2017) for more information.

[[Page 20056]]

As shown in table 87, the maximum annual allowable instances of
take by Level B harassment for Delphinid stocks ranges from 1 (Sabine
Lake bottlenose dolphin stock) to 269,405 for the Western North
Atlantic common dolphin, with 24 stocks below 2,000, seven stocks above
70,000, and the remainder between 2,000 and 38,000. Take by Level A
harassment is 0 for 17 of the 53 stocks, above 15 for 11 stocks, and 11
or fewer for the remaining stocks. As indicated, the rule also allows
for 1-2 takes annually by serious M/SI for five stocks (the Northern
Gulf of America stocks of striped and pantropical dolphins, the Western
North Atlantic offshore stock of bottlenose dolphins, the Western North
Atlantic South Carolina/Georgia Coastal stock of Tamanend's bottlenose
dolphin, and the Western North Atlantic stock of Clymene dolphins), the
impacts of which are discussed above in the Mortality section. The
total take allowable across all 7 years of the rule is indicated in
table 49.
All but two Delphinid stocks are expected to incur some number of
takes in the form of TTS. As described in the Auditory Injury from
Sonar Acoustic Sources and Explosives and Non-Auditory Injury from
Explosives section above, these temporary hearing impacts are expected
to be lower-level, of short duration (from minutes to at most several
hours or less than a day), and mostly not in a frequency band that
would be expected to interfere with delphinid echolocation, overlap
more than a relatively narrow portion of the vocalization range of any
single species or stock, or preclude detection or interpretation of
important low-frequency cues. Any associated lost opportunities or
capabilities individuals might experience as a result of TTS would not
be at a level or duration that would be expected to impact reproductive
success or survival. About two-thirds of the affected Delphinid stocks
will incur some number of takes by AUD INJ, the majority of single
digits, with higher numbers exceding 50 and up to 161 for several
stocks. For reasons similar to those discussed for TTS, while AUD INJ
impacts are permanent, given the anticipated effectiveness of the
mitigation and the likelihood that individuals are expected to avoid
higher levels associated with more severe impacts, the lower
anticipated levels of PTS that could be reasonably expected to result
from these activities are unlikely to affect the fitness of any
individuals. Five stocks are projected to incur notably higher numbers
of take by AUD INJ (85-161, the Western North Atlantic stocks of
Atlantic spotted dolphins, common dolphins, Clymene dolphins, striped
dolphins, and offshore bottlenose dolphins) and while the conclusions
above are still applicable, it is further worth noting that these five
stocks have relatively large abundances and limited annual mortality as
compared to PBR. The rule also allows for a limited number of takes by
non-auditory injury (1-3) for 15 stocks. As described above in the
Auditory Injury from Sonar Acoustic Sources and Explosives and Non-
Auditory Injury from Explosives section, given the small number of
potential exposures and the anticipated effectiveness of the mitigation
measures in minimizing the pressure levels to which any individuals are
exposed, these non-auditory injuries are unlikely to be of a nature or
level that would impact reproduction or survival.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 178 dB SPL and last from a
few minutes to a few hours, at most, with associated responses most
likely in the form of moving away from the source, foraging
interruptions, vocalization changes, or disruption of other social
behaviors, lasting from a few minutes to several hours. Delphinids are
income breeders with a medium pace of life, meaning that while they can
be sensitive to the consequences of disturbances that impact foraging
during lactation, from a population standpoint, they can be moderately
quick to recover. Further, as described in the Group and Species-
Specific Analyses section above and the Proposed Mitigation Measures
section, mitigation measures are expected to further reduce the
potential severity of impacts through real-time operational measures
that minimize higher level/longer duration exposures and time/area
measures that reduce impacts in higher value habitat.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In the case of just over
half of the delphinid stocks (see the Maximum Annual Harassment As
Percentage of Stock Abundance column in table 87), given the low number
of takes by harassment as compared to the stock/species abundance
alone, and also in consideration of their migratory movement pattern
and whether take is concentrated in areas in which animals are known to
congregate, it is unlikely that these individual Delphinids would be
taken on more than a small number of days within a year and, therefore,
the anticipated behavioral disturbance is not expected to affect
reproduction or survival. In the case of the rest of the stocks, with
the exception of the Northern North Carolina Estuarine System stock of
bottlenose dolphins (addressed below), given the number of takes by
harassment as compared to the stock/species abundance, it is likely
that some portion of the individuals taken are taken repeatedly over a
small to moderate number of days (as indicated in the Greatest Degree
Any Individual Expected to be Taken Repeatedly Across Multiple days
column of table 87). However, given the variety of activity types that
contribute to take across separate exercises conducted at different
times and in different areas, and the fact that many result from
transient activities conducted at sea, for all but one of the stocks
(addressed below), it is unlikely that the anticipated small to
moderate number of repeated takes for a given individual would occur
clumped across sequential days in a manner likely to impact foraging
success and energetics or other behaviors such that reproduction or
survival of any individuals are likely to be impacted. Further, many of
these stocks are nomadic or migratory and apart from the few small
resident dolphin populations, there are no known foraging areas or
other areas within which animals are known to congregate for important
behaviors, and nor are the takes concentrated within a specific region
and season.
Regarding the magnitude of repeated takes for the Northern North
Carolina Estuarine System stock of bottlenose dolphins, given the
number of takes by harassment as compared to the stock/species
abundance, the small resident population, the fact that the predicted
takes all occur in summer and are primarily from hull-mounted sonar
pierside or navigating out of Norfolk (see appendix A to the
application), it is more likely that some number of individuals
occupying that area during the summer months would experience a
comparatively higher number of repeated takes over a potentially fair
number of sequential days. Due to the higher number of repeated takes
focused within a limited time period, it is thereby more likely that a
portion of the individuals occupying the area near Norfolk in the
summer (approximately 50 percent of which would be female) could be
repeatedly interrupted during foraging in a manner and amount such that
impacts to the energy budgets of a

[[Page 20057]]

small number of females (from either losing feeding opportunities or
expending considerable energy moving away from sound sources or finding
alternative feeding options) could cause them to forego reproduction
for a year (noting that bottlenose dolphin calving intervals are
typically three or more years). Energetic impacts to males are
generally meaningless to population rates unless they cause death, and
it takes extreme energy deficits beyond what would ever be likely to
result from these activities to cause the death of an adult marine
mammal, male or female. This stock is considered potentially stable
and, while strategic, is not depleted. Importantly, the increase in a
calving interval by a year would have far less of an impact on a
population rate than a mortality would and, accordingly, a small number
of instances of foregone reproduction would not be expected to
adversely affect this stock through effects on annual rates of
recruitment or survival (noting also that no mortality is predicted or
authorized for this stock).
Given the magnitude and severity of the take by harassment
discussed above and any anticipated habitat impacts, and in
consideration of the required mitigation measures and other information
presented, the Action Proponents' activities are unlikely to result in
impacts on the reproduction or survival of any individuals of Delphinid
stocks, with the exception of the five stocks for which 1-2 takes by M/
SI are predicted and the one stock for which an increased calving
interval could potentially occur. Regarding the Northern North Carolina
Estuarine System stock of bottlenose dolphins, as described above, we
do not anticipate the relatively small number of individuals that might
be taken over repeated days within the year in a manner that results in
a year of foregone reproduction to adversely affect the stock through
effects on rates of recruitment or survival, given the status of the
stock. Regarding the Northern Gulf of America stocks of striped and
pantropical dolphins, the Western North Atlantic offshore stock of
bottlenose dolphins, the Western North Atlantic offshore South
Carolina/Georgia stock of Tamanend's bottlenose dolphins, and the
Western North Atlantic Clymene dolphins, as described in the Mortality
section, given the status of the stocks and in consideration of other
ongoing anthropogenic mortality, the amount of allowed M/SI take
proposed here would not, alone, nor in combination with the impacts of
the take by harassment discussed above (which are not expected to
impact the reproduction or survival of any individuals for those
stocks), be expected to adversely affect rates of recruitment and
survival. Last, we are aware that some Northern Gulf of America stocks
of delphinids have experienced lower rates of reproduction and survival
since the DWH oil spill, however, those effects are reflected in the
SARs and other data considered in these analyses and do not change our
findings. For these reasons, we have determined that the total take
(considering annual maxima and across seven years) anticipated and
proposed for authorization would have a negligible impact on all
Delphinid species and stocks.
Porpoises--
Harbor porpoise are not listed as endangered or threatened under
the ESA, and the Gulf of Maine/Bay of Fundy stock is not considered
depleted or strategic under the MMPA. The stock abundance is 85,765
animals. There are no UMEs or other factors that cause particular
concern for this stock. A small and resident population BIA has been
identified for this stock (LeBrecque et al., 2015). There is no ESA-
designated critical habitat for harbor porpoise, as the species is not
ESA-listed. While the Gulf of Maine/Bay of Fundy stock of harbor
porpoises can be found from Greenland to North Carolina, they are
primarily concentrated in the southern Bay of Fundy and northern Gulf
of Maine during warmer months (summer), and from Maine to New Jersey
during colder months (fall and spring). Harbor porpoises face several
chronic anthropogenic and non-anthropogenic risk factors, including
fishery interaction, ocean noise, and climate change.

[[Page 20058]]

Table 89--Annual Estimated Take by Level B Harassment, Level A Harassment, and Mortality and Related Information for Porpoises in the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum
annual
Maximum Maximum Maximum Maximum harassment Season(s) with 40 Region(s) with 40
Marine mammal species Stock NMFS stock NMSDD annual annual annual annual as percent of take or percent of take or
abundance abundance Level B Level A mortality take percentage greater greater
harassment harassment of stock
abundance
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor porpoise.................... Gulf of Maine/Bay of * 85,765 10,270 87,119 147 0 87,266 102 Winter (48 percent). Northeast (85
Fundy. Spring (45 percent). percent).
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: NMSDD abundances are averages only within the U.S. EEZ.
* Indicates which abundance estimate was used to calculate the maximum annual take as a percentage of abundance, either the NMFS SAR (Hayes et al., 2024) or the NMSDD (table 2.4-1 in appendix
A of the application). Please refer to the following section for details on which abundance estimate was selected.

Table 90--Life History Traits, Important Habitat, and Threats to Porpoises in the AFTT Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Annual
Movement Reproductive Chronic risk UME, oil spill, ESA-designated BIAs (LaBrecque Other important Population mortality/
Marine mammal species Stock ESA status MMPA status ecology Body size strategy Pace of life factors other critical et al. 2015) habitat trend PBR serious
habitat injury
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor porpoise.............. Gulf of Maine/ Not Listed..... Not depleted; Resident- Small.......... Income......... Fast........... Fishery No............. No............. Yes: Small and N/A............ Unk............ 649 142.4
Bay of Fundy. Not strategic. nomadic. interaction, resident
ocean noise, population
climate change. (n=1).
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: N/A = Not Applicable; Unk = Unknown.

[[Page 20059]]

As shown in table 89, the maximum annual allowable instances of
take under this proposed rule by Level A Harassment and Level B
harassment is 147 and 87,119, respectively. No mortality is anticipated
or proposed for authorization, and nor is any non-auditory injury. The
total take allowable across all 7 years of the rule is indicated in
table 49.
Regarding the potential takes associated with auditory impairment,
as VHF cetaceans, harbor porpoises are more susceptible to auditory
impacts in mid- to high frequencies and from explosives than other
species. As described in the Temporary Threshold Shift section above,
any takes in the form of TTS are expected to be lower-level, of short
duration (even the longest recovering in less than a day), and mostly
not in a frequency band that would be expected to interfere with
porpoise communication or other important auditory cues. Any associated
lost opportunities or capabilities individuals might experience as a
result of TTS would not be at a level or duration that would be
expected to impact reproductive success or survival. For similar
reasons, while auditory injury impacts last longer, the low anticipated
levels of AUD INJ that could be reasonably expected to result from
these activities are unlikely to have any effect on fitness.
Harbor porpoises are more susceptible to behavioral disturbance
than other species. They are highly sensitive to many sound sources and
generally demonstrate strong avoidance of most types of acoustic
stressors. The information currently available regarding harbor
porpoises suggests a very low threshold level of response for both
captive (Kastelein et al., 2000; Kastelein et al., 2005) and wild
(Johnston, 2002) animals. Southall et al. (2007) concluded that harbor
porpoises are likely sensitive to a wide range of anthropogenic sounds
at low received levels (approximately 90 to 120 dB). Research and
observations of harbor porpoises for other locations show that this
species is wary of human activity and will display profound avoidance
behavior for anthropogenic sound sources in many situations at levels
down to 120 dB re: 1 [micro]Pa (Southall, 2007). Harbor porpoises
routinely avoid and swim away from large motorized vessels (Barlow et
al., 1988; Evans et al., 1994; Palka and Hammond, 2001; Polacheck and
Thorpe, 1990). Accordingly, and as described in the Estimated Take of
Marine Mammals section, the threshold for behavioral disturbance is
lower for harbor porpoises, and the number of estimated takes is
higher, with many occurring at lower received levels than other taxa.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 154 dB SPL and last from a
few minutes to a few hours, at most. Associated responses would likely
include avoidance, foraging interruptions, vocalization changes, or
disruption of other social behaviors, lasting from a few minutes to
several hours and not likely to exceed 24 hours.
As small odontocetes and income breeders with a fast pace of life,
harbor porpoises are less resilient to missed foraging opportunities
than larger odontocetes. Although reproduction in populations with a
fast pace of life are more sensitive to foraging disruption, these
populations are quick to recover. Further, as described in the Group
and Species-Specific Analyses section above and the Proposed Mitigation
Measures section, mitigation measures are expected to further reduce
the potential severity of impacts through real-time operational
measures that minimize higher level/longer duration exposures and time/
area measures that reduce impacts in high value habitat.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. In this case, given the
number of takes by harassment as compared to the stock/species
abundance (see table 89), the small resident population and
concentration of takes (85 percent) in the Northeast, it is likely that
some portion of the individuals taken are taken repeatedly over a small
number of days. However, given the variety of activity types that
contribute to take across separate exercises conducted at different
times and in different areas, and the fact that many result from
transient activities conducted at sea, it is unlikely that repeated
takes would occur either in numbers or clumped across sequential days
in a manner likely to impact foraging success and energetics or other
behaviors such that reproduction or survival of any individuals is are
likely to be impacted.
Given the magnitude and severity of the impacts discussed above to
harbor porpoises (considering annual take maxima and the total across
seven years) and their habitat, and in consideration of the required
mitigation measures and other information presented, the Action
Proponents' activities are unlikely to result in impacts on the
reproduction or survival of any individuals and, thereby, unlikely to
affect annual rates of recruitment or survival. For these reasons, we
have determined that the take by harassment anticipated and proposed
for authorization would have a negligible impact on the Gulf of Maine/
Bay of Fundy stock of harbor porpoises.
Pinnipeds
This section builds on the broader discussion above and brings
together the discussion of the different types and amounts of take that
different stocks will incur, the applicable mitigation for each stock,
and the status and life history of the stocks to support the negligible
impact determinations for each stock. We have already described above
why we believe the incremental addition of the small number of low-
level auditory injury takes will not have any meaningful effect towards
inhibiting reproduction or survival. We have also described above in
this section the unlikelihood of any masking or habitat impacts having
effects that would impact the reproduction or survival of any of the
individual marine mammals affected by the Action Proponents'
activities. For pinnipeds, there is no predicted non-auditory injury
from explosives for any stock, and no predicted mortality for any
stock. Regarding the severity of individual takes by Level B harassment
by behavioral disturbance for pinnipeds, the majority of these
responses are anticipated to occur at received levels below 172 dB, and
last from a few minutes to a few hours, at most, with associated
responses most likely in the form of moving away from the source,
foraging interruptions, vocalization changes, or disruption of other
social behaviors, lasting from a few minutes to several hours. Because
of the small magnitude and severity of effects for all of the species,
it is not necessary to break out the findings by species or stock.
In table 91 below for pinnipeds, we indicate the total annual
mortality, Level A harassment, and Level B harassment, and a number
indicating the instances of total take as a percentage of abundance. In
table 92 below, we indicate the status, life history traits, important
habitats, and threats that inform our analysis of the potential impacts
of the estimated take on the affected pinniped stocks.
Gray seal, harbor seal, harp seal, and hooded seal are not listed
as endangered or threatened under the ESA, and these stocks are not
considered depleted or strategic under the MMPA. The

[[Page 20060]]

abundance estimates for both Western North Atlantic gray seals and
harbor seals are 27,911 and 61,336, but both of those estimates are for
the U.S. portion of the stock only, while each stock's range extends
into Canada. The estimated abundance of Western North Atlantic harp
seals is 7,600,600, and a current abundance estimate for hooded seals
is not available, though the most recent SAR (2018; Hayes et al., 2019)
estimated an abundance of 593,500 individuals. The range of both harp
seals and hooded seals also extends into Canada. In 2018, NMFS declared
a UME affecting both gray seals and harbor seals (Northeast Pinniped
UME, see Unusual Mortality Events section), but the UME is currently
non-active and pending closure, with infectious disease determined to
be the cause of the UME. The only known important areas for pinnipeds
in the AFTT Study Area are known gray whale pupping areas on Green
Island, Maine; Seal Island, Maine; and Muskeget Island, Maine.
Pinnipeds in the AFTT Study Area face several chronic anthropogenic and
non-anthropogenic risk factors, including entanglement, disease, and
climate change, among others.

[[Page 20061]]

Table 91--Annual Estimated Take by Level B Harassment, Level A Harassment, and Mortality and Related Information for Pinnipeds in the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum
annual
Maximum Maximum Maximum Maximum harassment Season(s) with 40 Region(s) with 40
Marine mammal species Stock NMFS stock NMSDD annual annual annual annual as Take in percent of take percent of take
abundance abundance Level B Level A mortality take percentage important areas or greater or greater
harassment harassment of stock
abundance
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Gray seal...................... Western North * 27,911 24,717 15,724 24 0 15,748 56 No............. Winter (44 Northeast (72
Atlantic. percent). percent).
Harbor seal.................... Western North * 61,336 10,184 22,094 32 0 22,126 36 No............. Winter (47 Northeast (69
Atlantic. percent). percent).
Harp seal...................... Western North * 10,007 25,792 6 0 25,798 0 No............. N/A.............. Northeast (100
Atlantic. 7,600,000 percent).
Hooded seal.................... Western North * Unk 1,097 1,726 2 0 1,728 Unk No............. N/A.............. Northeast (100
Atlantic. percent).
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Unk = Unknown, N/A = Not Applicable. NMSDD abundances are averages only within the U.S. EEZ.
* Indicates which abundance estimate was used to calculate the maximum annual take as a percentage of abundance, either the NMFS SAR (Hayes et al., 2024) or the NMSDD (table 2.4-1 in appendix
A of the application). Please refer to the following section for details on which abundance estimate was selected.

Table 92--Life History Traits, Important Habitat, and Threats to Pinnipeds in the AFTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Annual
Reproductive Chronic risk UME, oil spill, ESA-designated BIAs (LaBrecque Other important mortality/
Marine mammal species Stock ESA status MMPA status Movement ecology Body size strategy Pace of life factors other critical habitat et al. 2015) habitat Population trend PBR serious
injury
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Gray seal...................... Western North Not Listed........ Not Depleted...... Nomadic-migratory. Small............. Capital........... Fast.............. Entanglement, UME (declared No................ No............... Pupping: Green Increasing....... 756 4,491
Atlantic. Not Strategic..... illegal take/ 2018, pending Island, ME; Seal
killing, chemical closure). Island, ME;
contaminants, oil Muskeget Island,
spills and energy MA.
exploration,
vessel strike/
interaction,
disease, climate
change.
Harbor seal.................... Western North Not Listed........ Not Depleted...... Nomadic-migratory. Small............. Capital........... Fast.............. Entanglement, UME (declared No................ No............... None identified.. Stable/decline... 1,729 339
Atlantic. Not Strategic..... illegal feeding/ 2018, pending
harassment, closure).
habitat
degradation,
vessel strike,
chemical
contaminants,
disease, climate
change.
Harp seal...................... Western North Not Listed........ Not Depleted...... Migratory......... Small............. Capital........... Fast.............. Hunting, vessel No................ No................ No............... None identified.. Increasing....... 426,000 178,573
Atlantic. Not Strategic..... strike,
entanglement,
pollution, oil
spills/energy
exploration,
climate change,
prey limitations.

[[Page 20062]]

Hooded seal.................... Western North Not Listed........ Not Depleted...... Migratory......... Small............. Capital........... Fast.............. Vessel strike, No................ No................ No............... Three breeding Increasing....... Unk 1,680
Atlantic. Not Strategic..... habitat loss, areas in Canada.
entanglement,
harassment,
harmful algal
blooms, climate
change.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Unk = Unknown.

[[Page 20063]]

As shown in table 91, the maximum annual allowable instances of
take under this proposed rule by Level A Harassment and Level B
harassment range from 2 (hooded seal) to 32 (harbor seal) and 1,726
(hooded seal) to 25,792 (harp seal), respectively. No mortality is
anticipated or proposed for authorization, and nor is any non-auditory
injury. The total take allowable across all 7 years of the rule for
each stock is indicated in table 49.
Regarding the potential takes associated with auditory impairment,
as described above, any takes in the form of TTS are expected to be
lower-level, of short duration, and mostly not in a frequency band that
would be expected to interfere with pinniped communication or other
important low-frequency cues. Any associated lost opportunities or
capabilities individuals might experience as a result of TTS would not
be at a level or duration that would be expected to impact reproductive
success or survival. For similar reasons, while auditory injury impacts
last longer, the low anticipated levels of AUD INJ that could be
reasonably expected to result from these activities are unlikely to
have any effect on fitness.
Regarding the likely severity of any single instance of take by
behavioral disturbance, as described above, the majority of the
predicted exposures are expected to be below 172 dB SPL and last from a
few minutes to a few hours, at most, with associated responses most
likely in the form of moving away from the source, increased swimming
speeds, increased surfacing time, or foraging interruptions, lasting
from a few minutes to several hours. Pinnipeds have a fast pace of
life, but have a relatively lower energy requirement for their body
size, which may moderate any impact due to foraging disruption.
However, of note, harp seals have a large inter-annual variability in
reproductive rates due to variations in prey abundance (rely primarily
on capelin as their preferred prey) and mid-winter ice coverage and may
not reproduce as quickly as other pinnipeds. Also of note, gray seals
are likely to be exposed to Navy noise sources when in their more
southern habitats in the northeast region, especially in colder months
when they breed and give birth.
As described above, in addition to evaluating the anticipated
impacts of the single instances of takes, it is important to understand
the degree to which individual marine mammals may be disturbed
repeatedly across multiple days of the year. For gray seals and harbor
seals the SARs do not provide stock abundances that reflect the full
ranges of the stocks. For hooded seals, the SAR does not provide an up-
to-date abundance estimate for any portion of the stock's range. The
Navy's NMSDD abundance estimate for hooded seals was 1,097; however,
this estimate appears to be underestimated by several orders of
magnitude, as the most recent SAR estimate (2018 SAR; Hayes et al.
2019) was 593,500 animals. For all pinniped species, given the lower
number of takes by harassment as compared to the stock/species
abundance (accounting for the factors described above regarding
abundance estimates; see table 91), and their migratory or nomadic-
migratory movement patterns, it is unlikely that any individual
pinnipeds would be taken on more than a small number of days within a
year and, therefore, the anticipated behavioral disturbance is not
expected to affect reproduction or survival.
Given the magnitude and severity of the impacts discussed above
(considering annual maxima and across 7 years) and in consideration of
the required mitigation measures and other information presented, for
each pinniped stock, the Action Proponents' activities are not expected
to result in impacts on the reproduction or survival of any
individuals, much less affect annual rates of recruitment or survival.
Last, we have both considered the effects of the Northeast Pinniped
UME, pending closure, in our analysis and findings regarding the impact
of the activity on these stocks and also determined that we do not
expect the proposed take to exacerbate the effects of the UME or
otherwise impact the populations. For these reasons, we have determined
that the take by harassment anticipated and to be authorized would have
a negligible impact on all pinniped stocks.

Preliminary Determination

Based on the analysis contained herein of the likely effects of the
specified activities on marine mammals and their habitat, and taking
into consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the specified activity will have a negligible impact
on all affected marine mammal species or stocks.

Unmitigable Adverse Impact Analysis and Determination

There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.

Classification

Endangered Species Act

There are six marine mammal species under NMFS jurisdiction that
are listed as endangered or threatened under the ESA with confirmed or
possible occurrence in the AFTT Study Area: blue whale, fin whale,
NARW, Rice's whale, sei whale, and sperm whale. The NARW has critical
habitat designated under the ESA in the AFTT Study Area (81 FR 4837,
February 26, 2016) and the Rice's whale has proposed critical habitat
in the AFTT Study Area (88 FR 47453, July 24, 2023).
The Action Proponents will consult with NMFS pursuant to section 7
of the ESA for the AFTT Study Area activities. NMFS will also consult
internally on the issuance of the regulations and three LOAs under
section 101(a)(5)(A) of the MMPA.

National Marine Sanctuaries Act

The Action Proponents and NMFS will work with NOAA's Office of
National Marine Sanctuaries to fulfill our responsibilities under the
National Marine Sanctuaries Act as warranted and will complete any NMSA
requirements prior to a determination on the issuance of the final rule
and LOAs.

National Environmental Policy Act

To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed actions with respect to potential impacts
on the human environment. Accordingly, NMFS plans to adopt the 2024
AFTT Draft Supplemental EIS/OEIS for the AFTT Study Area, provided our
independent evaluation of the document finds that it includes adequate
information analyzing the effects on the human environment of issuing
regulations and LOAs under the MMPA. NMFS is a cooperating agency on
the 2024 AFTT Draft Supplemental EIS/OEIS and has worked extensively
with the Navy in developing the document. The 2024 AFTT Draft
Supplemental EIS/OEIS was made available for public comment at https://www.nepa.navy.mil/aftteis/, which also provides additional information
about the NEPA process, from September 20, 2024, to November 21, 2024.
We will review all comments

[[Page 20064]]

prior to concluding our NEPA process and making a final decision on the
MMPA rulemaking and request for LOAs.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
MMPA rule and request for LOAs.

Regulatory Flexibility Act

The Office of Management and Budget has determined that this
proposed rule is not significant for purposes of Executive Order 12866.
Pursuant to the Regulatory Flexibility Act (RFA), the Chief Counsel for
Regulation of the Department of Commerce has certified to the Chief
Counsel for Advocacy of the Small Business Administration that this
proposed rule, if adopted, would not have a significant economic impact
on a substantial number of small entities. The RFA requires Federal
agencies to prepare an analysis of a rule's impact on small entities
whenever the agency is required to publish a notice of proposed
rulemaking. However, a Federal agency may certify, pursuant to 5 U.S.C.
605(b), that the action will not have a significant economic impact on
a substantial number of small entities. The Action Proponents are the
only entities that would be affected by this rulemaking, and the Action
Proponents are not a small governmental jurisdiction, small
organization, or small business, as defined by the RFA. Any
requirements imposed by an LOA issued pursuant to these regulations,
and any monitoring or reporting requirements imposed by these
regulations, would be applicable only to the Action Proponents. NMFS
does not expect the issuance of these regulations or the associated
LOAs to result in any impacts to small entities pursuant to the RFA.
Because this action, if adopted, would directly affect only the Action
Proponents and not any small entities, NMFS concludes that the action
would not result in a significant economic impact on a substantial
number of small entities.

List of Subjects in 50 CFR Part 218

Administrative practice and procedure, Endangered and threatened
species, Fish, Fisheries, Marine mammals, Penalties, Reporting and
recordkeeping requirements, Transportation, Wildlife.

Dated: April 30, 2025.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, National Marine
Fisheries Service.

For reasons set forth in the preamble, NMFS proposes to amend 50
CFR part 218 as follows:

PART 218--REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE
MAMMALS

0
1. The authority citation for part 218 continues to read as follows:

Authority: 16 U.S.C. 1361 et seq.

0
2. Revise subpart I of part 218 to read as follows:

Subpart I--Taking and Importing Marine Mammals; Military Readiness
Activities in the Atlantic Fleet Training and Testing Study Area

Sec.
218.80 Specified activity and geographical region.
218.81 Effective dates.
218.82 Permissible methods of taking.
218.83 Prohibitions.
218.84 Mitigation requirements.
218.85 Requirements for monitoring and reporting.
218.86 Letters of Authorization.
218.87 Modifications of Letters of Authorization. 218.88-218.89
[Reserved]

Subpart I--Taking and Importing Marine Mammals; Military Readiness
Activities in the Atlantic Fleet Training and Testing Study Area

Sec. 218.80 Specified activity and geographical region.

(a) Regulations in this subpart apply only to the U.S. Navy (Navy)
and U.S. Coast Guard (Coast Guard) (collectively referred to as the
``Action Proponents'') for the taking of marine mammals that occurs in
the area described in paragraph (b) of this section and that occurs
incidental to the activities listed in paragraph (c) of this section.
(b) The taking of marine mammals by the Action Proponents under
this subpart may be authorized in Letters of Authorization (LOAs) only
if it occurs within the Atlantic Fleet Training and Testing (AFTT)
Study Area. The AFTT Study Area includes areas of the western Atlantic
Ocean along the east coast of North America, the Gulf of America, and
portions of the Caribbean Sea, covering approximately 2.6 million
nmi\2\ (8.9 million km\2\) of ocean, oriented from the mean high tide
line along the U.S. coast and extending east to 45[deg] W longitude
line, north to 65[deg] N latitude line, and south to approximately the
20[deg] N latitude line. It also includes Navy and Coast Guard pierside
locations, port transit channels, bays, harbors, inshore waterways
(e.g., channels, rivers), civilian ports where military readiness
activities occur, and vessel and aircraft transit routes among
homeports, designated operating areas (OPAREAs), and testing and
training ranges.
(c) The taking of marine mammals by the Action Proponents is only
authorized if it occurs incidental to the Action Proponents conducting
training and testing activities, including the following:
(1) Amphibious warfare;
(2) Anti-submarine warfare;
(3) Expeditionary warfare;
(4) Mine warfare;
(5) Surface warfare;
(6) Vessel evaluation;
(7) Unmanned systems;
(8) Acoustic and oceanographic science and technology;
(9) Vessel movement; and
(10) Other training and testing activities.

Sec. 218.81 Effective dates.

Regulations in this subpart are effective from November 14, 2025,
through November 13, 2032.

Sec. 218.82 Permissible methods of taking.

(a) Under LOAs issued pursuant to Sec. Sec. 216.106 of this
chapter and 218.87, the Holder of the LOAs (hereinafter ``Action
Proponents'') may incidentally, but not intentionally, take marine
mammals within the area described in Sec. 218.80(b) by Level A
harassment and Level B harassment associated with the use of active
sonar and other acoustic sources and explosives, as well as serious
injury or mortality associated with vessel strikes and explosives,
provided the activity is in compliance with all terms, conditions, and
requirements of this subpart and the applicable LOAs.
(b) The incidental take of marine mammals by the activities listed
in Sec. 218.80(c) is limited to the following species:

[[Page 20065]]

Table 1 to Paragraph (b)
------------------------------------------------------------------------
Species Stock
------------------------------------------------------------------------
North Atlantic right whale............. Western.
Blue whale............................. Western North Atlantic.
Bryde's whale.......................... Primary.
Fin whale.............................. Western North Atlantic.
Humpback whale......................... Gulf of Maine.
Minke whale............................ Canadian Eastern Coast.
Rice's whale........................... Northern Gulf of America.
Sei whale.............................. Nova Scotia.
Sperm whale............................ North Atlantic.
Sperm whale............................ Northern Gulf of America.
Dwarf sperm whale...................... Northern Gulf of America.
Pygmy sperm whale...................... Northern Gulf of America.
Dwarf sperm whale...................... Western North Atlantic.
Pygmy sperm whale...................... Western North Atlantic.
Blainville's beaked whale.............. Northern Gulf of America.
Goose-beaked whale..................... Northern Gulf of America.
Gervais' beaked whale.................. Northern Gulf of America.
Blainville's beaked whale.............. Western North Atlantic.
Goose-beaked whale..................... Western North Atlantic.
Gervais' beaked whale.................. Western North Atlantic.
Northern bottlenose whale.............. Western North Atlantic.
Sowerby's beaked whale................. Western North Atlantic.
True's beaked whale.................... Western North Atlantic.
Atlantic spotted dolphin............... Northern Gulf of America.
Bottlenose dolphin..................... Gulf of America Eastern
Coastal.
Bottlenose dolphin..................... Gulf of America Northern
Coastal.
Bottlenose dolphin..................... Gulf of America, Oceanic.
Bottlenose dolphin..................... Gulf of America Western
Coastal.
Bottlenose dolphin..................... Mississippi Sound, Lake Borgne,
and Bay Boudreau.
Bottlenose dolphin..................... Northern Gulf of America
Continental Shelf.
Bottlenose dolphin..................... Nueces and Corpus Christi Bays.
Bottlenose dolphin..................... Sabine Lake.
Bottlenose dolphin..................... St. Andrew Bay.
Bottlenose dolphin..................... St. Joseph Bay.
Bottlenose dolphin..................... Tampa Bay.
Clymene dolphin........................ Northern Gulf of America.
False killer whale..................... Northern Gulf of America.
Fraser's dolphin....................... Northern Gulf of America.
Killer whale........................... Northern Gulf of America.
Melon-headed whale..................... Northern Gulf of America.
Pygmy killer whale..................... Northern Gulf of America.
Risso's dolphin........................ Northern Gulf of America.
Rough-toothed dolphin.................. Northern Gulf of America.
Short-finned pilot whale............... Northern Gulf of America.
Striped dolphin........................ Northern Gulf of America.
Pantropical spotted dolphin............ Northern Gulf of America.
Spinner dolphin........................ Northern Gulf of America.
Atlantic white-sided dolphin........... Western North Atlantic.
Common dolphin......................... Western North Atlantic.
Atlantic spotted dolphin............... Western North Atlantic.
Bottlenose dolphin..................... Indian River Lagoon Estuarine
System.
Bottlenose dolphin..................... Jacksonville Estuarine System.
Bottlenose dolphin..................... Northern Georgia/Southern South
Carolina Estuarine System.
Bottlenose dolphin..................... Northern North Carolina
Estuarine System.
Bottlenose dolphin..................... Southern Georgia Estuarine
System.
Bottlenose dolphin..................... Southern North Carolina
Estuarine System.
Tamanend's bottlenose dolphin.......... Western North Atlantic Central
Florida Coastal.
Tamanend's bottlenose dolphin.......... Western North Atlantic Northern
Florida Coastal.
Bottlenose dolphin..................... Western North Atlantic Northern
Migratory Coastal.
Bottlenose dolphin..................... Western North Atlantic
Offshore.
Tamanend's bottlenose dolphin.......... Western North Atlantic South
Carolina/Georgia Coastal.
Bottlenose dolphin..................... Western North Atlantic Southern
Migratory Coastal.
Clymene dolphin........................ Western North Atlantic.
False killer whale..................... Western North Atlantic.
Fraser's dolphin....................... Western North Atlantic.
Killer whale........................... Western North Atlantic.
Long-finned pilot whale................ Western North Atlantic.
Melon-headed whale..................... Western North Atlantic.
Pantropical spotted dolphin............ Western North Atlantic.
Pygmy killer whale..................... Western North Atlantic.
Risso's dolphin........................ Western North Atlantic.
Rough-toothed dolphin.................. Western North Atlantic.

[[Page 20066]]

Short-finned pilot whale............... Western North Atlantic.
Spinner dolphin........................ Western North Atlantic.
Striped dolphin........................ Western North Atlantic.
White-beaked dolphin................... Western North Atlantic.
Harbor porpoise........................ Gulf of Maine/Bay of Fundy.
Gray seal.............................. Western North Atlantic.
Harbor seal............................ Western North Atlantic.
Harp seal.............................. Western North Atlantic.
Hooded seal............................ Western North Atlantic.
------------------------------------------------------------------------

Sec. 218.83 Prohibitions.

(a) Except incidental take described in Sec. 218.82 and authorized
by a LOA issued under this subpart, it shall be unlawful for any person
to do the following in connection with the activities described in this
subpart:
(1) Violate, or fail to comply with, the terms, conditions, and
requirements of this subpart or a LOA issued under Sec. Sec. 216.106
of this chapter, 218.86, or 218.87;
(2) Take any marine mammal not specified in Sec. 218.82(b);
(3) Take any marine mammal specified in Sec. 218.82(b) in any
manner other than as specified in the LOAs; or
(4) Take a marine mammal specified in Sec. 218.82(b) after NMFS
determines such taking results in more than a negligible impact on the
species or stock of such marine mammal.
(b) [Reserved]

Sec. 218.84 Mitigation requirements.

(a) When conducting the activities identified in Sec. 218.80(c),
the mitigation measures contained in this section and any LOA issued
under Sec. Sec. 218.86 or 218.87 must be implemented by Action
Proponent personnel or contractors who are trained according to the
requirements in the LOA. If Action Proponent contractors are serving in
a role similar to Action Proponent personnel, Action Proponent
contractors must follow the mitigation applicable to Action Proponent
personnel. These mitigation measures include, but are not limited to:
(1) Activity-based mitigation. Activity-based mitigation is
mitigation that the Action Proponents must implement whenever and
wherever an applicable training or testing activity takes place within
the AFTT Study Area. The Action Proponents must implement the
mitigation described in paragraphs (a)(1)(i) through (a)(1)(xxi) of
this section, except as provided in paragraph (a)(1)(xxii).
(i) Active acoustic sources with power down and shut down
capabilities. For active acoustic sources with power down and shutdown
capabilities (low-frequency active sonar >=200 dB, mid-frequency active
sonar sources that are hull mounted on a surface ship (including
surfaced submarines), and broadband and other active acoustic sources
>200 dB):
(A) Mitigation zones and requirements. During active acoustic
sources with power down and shutdown capabilities, the following
mitigation zone requirements apply:
(1) At 1,000 yd (914.4 m) from a marine mammal, Action Proponent
personnel must power down active acoustic sources by 6 decibels (dB)
total.
(2) At 500 yd (457.2 m) from a marine mammal, Action Proponent
personnel must power down active acoustic sources by 10 dB total.
(3) At 200 yd (182.9 m) from a marine mammal, Action Proponent
personnel must shut down active acoustic sources.
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout in or on one of the following: aircraft; pierside,
moored, or anchored vessel; underway vessel with space/crew
restrictions (including small boats); or underway vessel already
participating in the event that is escorting (and has positive control
over sources used, deployed, or towed by) an unmanned platform.
(2) Two Lookouts on an underway vessel without space or crew
restrictions.
(3) Lookouts must use information from passive acoustic detections
to inform visual observations when passive acoustic devices are already
being used in the event.
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals and floating vegetation immediately
prior to the initial start of using active acoustic sources (e.g.,
while maneuvering on station).
(2) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals during use of active acoustic
sources.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing or powering up active sonar transmission). The wait period
for this activity is 30 minutes for activities conducted from vessels
and for activities conducted by aircraft that are not fuel constrained
and 10 minutes for activities involving aircraft that are fuel
constrained (e.g., rotary-wing aircraft, fighter aircraft).
(ii) Active acoustic sources with shut down capabilities only (no
power down capability). For active acoustic sources with shut down
capabilities only (no power down capability) (low-frequency active
sonar <200 dB, mid-frequency active sonar sources that are not hull
mounted on a surface ship (e.g., dipping sonar, towed arrays), high-
frequency active sonar, air guns, and broadband and other active
acoustic sources <200 dB):
(A) Mitigation zones and requirements. During use of active
acoustic sources with shut down capabilities only, the following
mitigation zone requirements apply:
(1) At 200 yd (182.9 m) from a marine mammal, Action Proponent
personnel must shut down active acoustic sources.
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout in or on one of the following: aircraft; pierside,
moored, or anchored vessel; underway vessel with space/crew
restrictions (including small boats); or underway vessel already
participating in the event that is escorting (and has positive control
over sources used, deployed, or towed by) an unmanned platform.
(2) Two Lookouts on an underway vessel without space or crew
restrictions.
(3) Lookouts must use information from passive acoustic detections
to

[[Page 20067]]

inform visual observations when passive acoustic devices are already
being used in the event.
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals and floating vegetation immediately
prior to the initial start of using active acoustic sources (e.g.,
while maneuvering on station).
(2) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals during use of active acoustic
sources.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing or powering up active sonar transmission. The wait period
for this activity is 30 minutes for activities conducted from vessels
and for activities conducted by aircraft that are not fuel constrained
and 10 minutes for activities involving aircraft that are fuel
constrained (e.g., rotary-wing aircraft, fighter aircraft).
(iii) Pile driving and extraction. For pile driving and extraction:
(A) Mitigation zones and requirements. During vibratory and impact
pile driving and extraction, the following mitigation zone requirements
apply:
(1) Action Proponent personnel must cease pile driving or
extraction if a marine mammal is sighted within 100 yd (91.4 m) of a
pile being driven or extracted.
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout in or on one of the following: shore, pier, or
small boat.
(2) [Reserved]
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the mitigation zone for
marine mammals and floating vegetation for 15 minutes prior to the
initial start of pile driving or pile extraction.
(2) Action Proponent personnel must observe the mitigation zone for
marine mammals during pile driving or extraction.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing vibratory and impact pile driving and extraction). The
wait period for this activity is 15 minutes.
(iv) Weapons firing noise. For weapons firing noise:
(A) Mitigation zones and requirements. During explosive and non-
explosive large-caliber gunnery firing noise (surface-to-surface and
surface-to-air), the following mitigation zone requirements apply:
(1) Action Proponent personnel must cease weapons firing if a
marine mammal is sighted within 30 degrees on either side of the firing
line out to 70 yd (64 m) from the gun muzzle (cease fire).
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout on a vessel.
(2) [Reserved]
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the mitigation zone for
marine mammals and floating vegetation immediately prior to the initial
start of large-caliber gun firing (e.g., during target deployment).
(2) Action Proponent personnel must observe the mitigation zone for
marine mammals during large-caliber gun firing.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing explosive and non-explosive large-caliber gunnery firing
noise (surface-to-surface and surface-to-air)). The wait period for
this activity is 30 minutes.
(v) Explosive bombs. For explosive bombs:
(A) Mitigation zones and requirements. During the use of explosive
bombs of any net explosive weight (NEW), the following mitigation zone
requirements apply:
(1) Action Proponent personnel must cease explosive bomb use if a
marine mammal is sighted within 2,500 yd (2,286 m) from the intended
target.
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout in an aircraft.
(2) [Reserved]
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals and floating vegetation immediately
prior to the initial start of bomb delivery (e.g., when arriving on
station).
(2) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals during bomb delivery.
(3) After the event, when practical, Action Proponent personnel
must observe the detonation vicinity for injured or dead marine
mammals. If any injured or dead marine mammals are observed, Action
Proponent personnel must follow established incident reporting
procedures.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing use of explosive bombs of any NEW). The wait period for
this activity is 10 minutes.
(vi) Explosive gunnery. For explosive gunnery:
(A) Mitigation zones and requirements. During air-to-surface
medium-caliber, surface-to-surface medium-caliber, surface-to-surface
large-caliber explosive gunnery, the following mitigation zone
requirements apply:
(1) Action Proponent personnel must cease air-to-surface medium-
caliber use if a marine mammal is sighted within 200 yd (182.9 m) of
the intended impact location.
(2) Action Proponent personnel must cease surface-to-surface
medium-caliber use if a marine mammal is sighted within 600 yd (548.6
m) of the intended impact location.
(3) Action Proponent personnel must cease surface-to-surface large-
caliber use if a marine mammal is sighted within 1,000 yd (914.4 m) of
the intended impact location.
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout on a vessel or in an aircraft.
(2) [Reserved]
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals and floating vegetation immediately
prior to the initial start of gun firing (e.g., while maneuvering on
station).

[[Page 20068]]

(2) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals during gunnery fire.
(3) After the event, when practical, Action Proponent personnel
must observe the detonation vicinity for injured or dead marine
mammals. If any injured or dead marine mammals are observed, Action
Proponent personnel must follow established incident reporting
procedures.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing air-to-surface medium-caliber, surface-to-surface medium-
caliber, surface-to-surface large-caliber explosive gunnery). The wait
period for this activity is 30 minutes for activities conducted from
vessels and for activities conducted by aircraft that are not fuel
constrained and 10 minutes for activities involving aircraft that are
fuel constrained (e.g., rotary-wing aircraft, fighter aircraft).
(vii) Explosive line charges. For explosive line charges:
(A) Mitigation zones and requirements. During the use of explosive
line charges of any NEW, the following mitigation zone requirements
apply:
(1) Action Proponent personnel must cease explosive line charges if
a marine mammal is sighted within 900 yd (823 m) of the detonation
site.
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout on a vessel.
(2) [Reserved]
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the mitigation zone for
marine mammals and floating vegetation immediately prior to the initial
start of detonations (e.g., while maneuvering on station).
(2) Action Proponent personnel must observe the mitigation zone for
marine mammals during detonations.
(3) After the event, when practical, Action Proponent personnel
must observe the detonation vicinity for injured or dead marine
mammals. If any injured or dead marine mammals are observed, Action
Proponent personnel must follow established incident reporting
procedures.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing use of explosive line charges of any NEW). The wait period
for this activity is 30 minutes.
(viii) Explosive mine countermeasure and neutralization (no
divers). For explosive mine countermeasure neutralization (no divers):
(A) Mitigation zones and requirements. During explosive mine
countermeasure and neutralization using 0.1-5 pound (lb) (0.05-2.3
kilogram (kg)) NEW and >5 lb (2.3 kg) NEW, the following mitigation
zone requirements apply:
(1) Action Proponent personnel must cease 0.1-5 lb (0.05-2.3 kg)
NEW use if a marine mammal is sighted within 600 yd (548.6 m) of
detonation site.
(2) Action Proponent personnel must cease >5 lb (2.3 kg) NEW use if
a marine mammal is sighted within 2,100 yd (1,920.2 m) of the
detonation site.
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout on a vessel or in an aircraft during 0.1-5 lb
(0.05-2.3 kg) NEW use.
(2) Two Lookouts: one on a small boat and one in an aircraft during
>5 lb (2.3 kg) NEW use.
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals and floating vegetation immediately
prior to the initial start of detonations (e.g., while maneuvering on
station; typically, 10 or 30 minutes depending on fuel constraints).
(2) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals during detonations or fuse
initiation.
(3) After the event, when practical, Action Proponent personnel
must observe the detonation vicinity for 10 or 30 minutes (depending on
fuel constraints) for injured or dead marine mammals. If any injured or
dead marine mammals are observed, Action Proponent personnel must
follow established incident reporting procedures.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing explosive mine countermeasure and neutralization using
0.1-5 pound (lb) (0.05-2.3 kilogram (kg)) NEW and >5 lb (2.3 kg) NEW).
The wait period for this activity is 30 minutes for activities
conducted from vessels and for activities conducted by aircraft that
are not fuel constrained and 10 minutes for activities involving
aircraft that are fuel constrained (e.g., rotary-wing aircraft, fighter
aircraft).
(ix) Explosive mine neutralization (with divers). For explosive
mine neutralization (with divers):
(A) Mitigation zones and requirements. During explosive mine
neutralization (with divers) using 0.1-20 lb (0.05-9.1 kg) NEW
(positive control), 0.1-20 lb (0.05-9.1 kg) NEW (time-delay), and >20-
60 lb (9.1-27.2 kg) NEW (positive control), the following mitigation
zone requirements apply:
(1) Action Proponent personnel must cease 0.1-20 lb (0.05-9.1 kg)
NEW (positive control) use if a marine mammal is sighted within 500 yd
(457.2 m) of the detonation site (cease fire).
(2) Action Proponent personnel must cease 0.1-20 lb (0.05-9.1 kg)
NEW (time-delay) and >20-60 lb (9.1-27.2 kg) NEW (positive control) use
if a marine mammal is sighted within 1,000 yd (914.4 m) of the
detonation site (cease fire).
(B) Lookout requirements. The following Lookout requirements apply:
(1) Two Lookouts in two small boats (one Lookout per boat) or one
small boat and one rotary-wing aircraft (with one Lookout each) during
0.1-20 lb (0.05-9.1 kg) NEW (positive control) use.
(2) Four Lookouts in two small boats (two Lookouts per boat) and
one additional Lookout in an aircraft if used in the event during 0.1-
20 lb (0.05-9.1 kg) NEW (time-delay) and >20-60 lb (9.1-27.2 kg) NEW
(positive control) use.
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Time-delay devices must be set not to exceed 10 minutes.
(2) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals and floating vegetation immediately
prior to the initial start of detonations or fuse initiation for
positive control events (e.g., while maneuvering on station) or for 30
minutes prior for time-delay events.
(3) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals during detonations or fuse
initiation.

[[Page 20069]]

(4) When practical based on mission, safety, and environmental
conditions:
(i) Boats must observe from the mitigation zone radius mid-point.
(ii) When two boats are used, boats must observe from opposite
sides of the mine location.
(iii) Platforms must travel a circular pattern around the mine
location.
(iv) Boats must have one Lookout observe inward toward the mine
location and one Lookout observe outward toward the mitigation zone
perimeter.
(v) Divers must be part of the Lookout Team.
(5) After the event, when practical, Action Proponent personnel
must observe the detonation vicinity for 30 minutes for injured or dead
marine mammals. If any injured or dead marine mammals are observed,
Action Proponent personnel must follow established incident reporting
procedures.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing explosive mine neutralization (with divers) using 0.1-20
lb (0.05-9.1 kg) NEW (positive control), 0.1-20 lb (0.05-9.1 kg) NEW
(time-delay), and >20-60 lb (9.1-27.2 kg) NEW (positive control)). The
wait period for this activity is 30 minutes for activities conducted
from vessels and for activities conducted by aircraft that are not fuel
constrained and 10 minutes for activities involving aircraft that are
fuel constrained (e.g., rotary-wing aircraft, fighter aircraft).
(x) Explosive missiles and rockets. For explosive missiles and
rockets:
(A) Mitigation zones and requirements. During the use of explosive
missiles and rockets using 0.6-20 lb (0.3-9.1 kg) NEW (air-to-surface)
and >20-500 lb (9.1-226.8 kg) NEW (air-to-surface), the following
mitigation zone requirements apply:
(1) Action Proponent personnel must cease 0.6-20 lb (0.3-9.1 kg)
NEW (air-to-surface) use if a marine mammal is sighted within 900 yd
(823 m) of the intended impact location (cease fire).
(2) Action Proponent personnel must cease >20-500 lb (9.1-226.8 kg)
NEW (air-to-surface) use if a marine mammal is sighted within 2,000 yd
(1,828.8 m) of the intended impact location (cease fire).
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout in an aircraft.
(2) [Reserved]
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals and floating vegetation immediately
prior to the initial start of missile or rocket delivery (e.g., during
a fly-over of the mitigation zone).
(2) Action Proponent personnel must observe the applicable
mitigation zone for marine mammals during missile or rocket delivery.
(3) After the event, when practical, Action Proponent personnel
must observe the detonation vicinity for injured or dead marine
mammals. If any injured or dead marine mammals are observed, Action
Proponent personnel must follow established incident reporting
procedures.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing use of explosive missiles and rockets using 0.6-20 lb
(0.3-9.1 kg) NEW (air-to-surface) and >20-500 lb (9.1-226.8 kg) NEW
(air-to-surface)). The wait period for this activity is 30 minutes for
activities conducted from vessels and for activities conducted by
aircraft that are not fuel constrained and 10 minutes for activities
involving aircraft that are fuel constrained (e.g., rotary-wing
aircraft, fighter aircraft).
(xi) Explosive sonobuoys and research-based sub-surface explosives.
For explosive sonobuoys and research-based sub-surface explosives:
(A) Mitigation zones and requirements. During the use of explosive
sonobuoys and research-based sub-surface explosives using any NEW of
sonobuoys and 0.1-5 lb (0.05-2.3 kg) NEW for other types of sub-surface
explosives used in research applications, the following mitigation zone
requirements apply:
(1) Action Proponent personnel must cease use of explosive
sonobuoys and research-based sub-surface explosives using any NEW of
sonobuoys and 0.1-5 lb (0.05-2.3 kg) NEW for other types of sub-surface
explosives used in research applications if a marine mammal is sighted
within 600 yd (548.6 m) of the device or detonation sites (cease fire).
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout on a small boat or in an aircraft.
(2) Conduct passive acoustic monitoring for marine mammals; use
information from detections to assist visual observations.
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the mitigation zone for
marine mammals and floating vegetation immediately prior to the initial
start of detonations (e.g., during sonobuoy deployment, which typically
lasts 20-30 minutes).
(2) Action Proponent personnel must observe the mitigation zone for
marine mammals during detonations.
(3) After the event, when practical, Action Proponent personnel
must observe the detonation vicinity for injured or dead marine
mammals. If any injured or dead marine mammals are observed, Action
Proponent personnel must follow established incident reporting
procedures.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing use of explosive sonobuoys and research-based sub-surface
explosives using any NEW of sonobuoys and 0.1-5 lb (0.05-2.3 kg) NEW
for other types of sub-surface explosives used in research
applications). The wait period for this activity is 30 minutes for
activities conducted from vessels and for activities conducted by
aircraft that are not fuel constrained and 10 minutes for activities
involving aircraft that are fuel constrained (e.g., rotary-wing
aircraft, fighter aircraft).
(xii) Explosive torpedoes. For explosive torpedoes:
(A) Mitigation zones and requirements. During the use of explosive
torpedoes of any NEW, the following mitigation zone requirements apply:
(1) Action Proponent personnel must cease use of explosive
torpedoes of any NEW if a marine mammal is sighted within 2,100 yd
(1,920.2 m) of the intended impact location.
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout in an aircraft.
(2) Conduct passive acoustic monitoring for marine mammals; use
information from detections to assist visual observations.

[[Page 20070]]

(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the mitigation zone for
marine mammals, floating vegetation, and jellyfish aggregations
immediately prior to the initial start of detonations (e.g., during
target deployment).
(2) Action Proponent personnel must observe the mitigation zone for
marine mammals and jellyfish aggregations during torpedo launches.
(3) After the event, when practical, Action Proponent personnel
must observe the detonation vicinity for injured or dead marine
mammals. If any injured or dead marine mammals are observed, Action
Proponent personnel must follow established incident reporting
procedures.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing use of explosive torpedoes of any NEW). The wait period
for this activity is 30 minutes for activities conducted from vessels
and for activities conducted by aircraft that are not fuel constrained
and 10 minutes for activities involving aircraft that are fuel
constrained (e.g., rotary-wing aircraft, fighter aircraft).
(xiii) Ship shock trials. For ship shock trials:
(A) Mitigation zones and requirements. During ship shock trials
using any NEW, the following mitigation zone requirements apply:
(1) Action Proponent personnel must cease ship shock trials of any
NEW if a marine mammal is sighted within 3.5 nmi (6.5 km) of the target
ship hull (cease fire).
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) On the day of the event, 10 observers (Lookouts and third-party
observers combined), spread between aircraft or multiple vessels as
specified in the event-specific mitigation plan.
(2) [Reserved]
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must develop a detailed, event-
specific monitoring and mitigation plan in the year prior to the event
and provide it to NMFS for review.
(2) Beginning at first light on days of detonation, until the
moment of detonation (as allowed by safety measures) Action Proponent
personnel must observe the mitigation zone for marine mammals, floating
vegetation, jellyfish aggregations, large schools of fish, and flocks
of seabirds.
(3) If any dead or injured marine mammals are observed after an
individual detonation, Action Proponent personnel must follow
established incident reporting procedures and halt any remaining
detonations until Action Proponent personnel or third-party observers
can consult with NMFS and review or adapt the event-specific mitigation
plan, if necessary.
(4) During the 2 days following the event (minimum) and up to 7
days following the event (maximum), and as specified in the event-
specific mitigation plan, Action Proponent personnel must observe the
detonation vicinity for injured or dead marine mammals.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing ship shock trials). The wait period for this activity is
30 minutes.
(xiv) Sinking Exercises. For Sinking Exercises (SINKEX):
(A) Mitigation zones and requirements. During SINKEX using any NEW,
the following mitigation zone requirements apply:
(1) Action Proponent personnel must cease SINKEX of any NEW if a
marine mammal is sighted within 2.5 nmi (4.6 km) of the target ship
hull (cease fire).
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) Two Lookouts: one on a vessel and one in an aircraft.
(2) Conduct passive acoustic monitoring for marine mammals; use
information from detections to assist visual observations.
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) During aerial observations for 90 minutes prior to the initial
start of weapon firing, Action Proponent personnel must observe the
mitigation zone for marine mammals, floating vegetation, and jellyfish
aggregations.
(2) From the vessel during weapon firing, and from the aircraft and
vessel immediately after planned or unplanned breaks in weapon firing
of more than 2 hours, Action Proponent personnel must observe the
mitigation zone for marine mammals.
(3) Action Proponent personnel must observe the detonation vicinity
for injured or dead marine mammals for 2 hours after sinking the vessel
or until sunset, whichever comes first. If any injured or dead marine
mammals are observed, Action Proponent personnel must follow
established incident reporting procedures.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing SINKEX). The wait period for this activity is 30 minutes.
(xv) Non-explosive aerial-deployed mines and bombs. For non-
explosive aerial-deployed mines and bombs:
(A) Mitigation zones and requirements. During the use of non-
explosive aerial-deployed mines and non-explosive bombs, the following
mitigation zone requirements apply:
(1) Action Proponent personnel must cease using non-explosive
aerial-deployed mines and non-explosive bombs use if a marine mammal is
sighted within 1,000 yd (914.4 m) of the intended target (cease fire).
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout in an aircraft.
(2) [Reserved]
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the mitigation zone for
marine mammals and floating vegetation immediately prior to the initial
start of mine or bomb delivery (e.g., when arriving on station).
(2) Action Proponent personnel must observe the mitigation zone for
marine mammals during mine or bomb delivery.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing use of non-explosive aerial-deployed mines and non-
explosive bombs). The wait period for this activity is 10 minutes.
(xvi) Non-explosive gunnery. For non-explosive gunnery:
(A) Mitigation zones and requirements. During the use of non-

[[Page 20071]]

explosive surface-to-surface large-caliber ordnance, non-explosive
surface-to-surface and air-to-surface medium-caliber ordnance, and non-
explosive surface-to-surface and air-to-surface small-caliber ordnance,
the following mitigation zone requirements apply:
(1) Action Proponent personnel must cease non-explosive surface-to-
surface large-caliber ordnance, non-explosive surface-to-surface and
air-to-surface medium-caliber ordnance, and non-explosive surface-to-
surface and air-to-surface small-caliber ordnance use if a marine
mammal is sighted within 200 yd (182.9 m) of the intended impact
location (cease fire).
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout on a vessel or in an aircraft.
(2) [Reserved]
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the mitigation zone for
marine mammals and floating vegetation immediately prior to the start
of gun firing (e.g., while maneuvering on station).
(2) Action Proponent personnel must observe the mitigation zone for
marine mammals during gunnery firing.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing use of non-explosive surface-to-surface large-caliber
ordnance, non-explosive surface-to-surface and air-to-surface medium-
caliber ordnance, and non-explosive surface-to-surface and air-to-
surface small-caliber ordnance). The wait period for this activity is
30 minutes for activities conducted from vessels and for activities
conducted by aircraft that are not fuel constrained and 10 minutes for
activities involving aircraft that are fuel constrained (e.g., rotary-
wing aircraft, fighter aircraft).
(xvii) Non-explosive missiles and rockets. For non-explosive
missiles and rockets:
(A) Mitigation zones and requirements. During the use of non-
explosive missiles and rockets (air-to-surface), the following
mitigation zone requirements apply:
(1) Action Proponent personnel must cease non-explosive missile and
rocket (air-to-surface) use if a marine mammal is sighted within 900 yd
(823 m) of the intended impact location.
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout in an aircraft.
(2) [Reserved]
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the mitigation zone for
marine mammals and floating vegetation immediately prior to the start
of missile or rocket delivery (e.g., during a fly-over of the
mitigation zone).
(2) Action Proponent personnel must observe the mitigation zone for
marine mammals during missile or rocket delivery.
(D) Commencement or recommencement conditions. Action Proponent
personnel must ensure one of the commencement or recommencement
conditions in Sec. 218.84(a)(1)(xxi) is met prior to the initial start
of the activity (by delaying the start) or during the activity (by not
recommencing use of non-explosive missiles and rockets (air-to-
surface)). The wait period for this activity is 30 minutes for
activities conducted from vessels and for activities conducted by
aircraft that are not fuel constrained and 10 minutes for activities
involving aircraft that are fuel constrained (e.g., rotary-wing
aircraft, fighter aircraft).
(xviii) Manned surface vessels. For manned surface vessels:
(A) Mitigation zones and requirements. During the use of manned
surface vessels, including surfaced submarines, the following
mitigation zone requirements apply:
(1) Underway manned surface vessels must maneuver themselves (which
may include reducing speed) to maintain the following distances as
mission and circumstances allow:
(i) 500 yd (457.2 m) from whales.
(ii) 200 yd (182.9 m) from other marine mammals.
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) One or more Lookouts on manned underway surface vessels in
accordance with the most recent navigation safety instruction.
(2) [Reserved]
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the mitigation zone for
marine mammals immediately prior to manned surface vessels getting
underway and while underway.
(2) [Reserved]
(xix) Unmanned vehicles. For unmanned vehicles:
(A) Mitigation zones and requirements. During the use of unmanned
surface vehicles and unmanned underwater vehicles already being
escorted (and operated under positive control) by a manned surface
support vessel, the following mitigation zone requirements apply:
(1) A surface support vessel that is already participating in the
event, and has positive control over the unmanned vehicle, must
maneuver the unmanned vehicle (which may include reducing its speed) to
ensure it maintains the following distances as mission and
circumstances allow:
(i) 500 yd (457.2 m) from whales.
(ii) 200 yd (182.9 m) from other marine mammals.
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout on a surface support vessel that is already
participating in the event, and has positive control over the unmanned
vehicle.
(2) [Reserved]
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the mitigation zone for
marine mammals immediately prior to unmanned vehicles getting underway
and while underway.
(2) [Reserved]
(xx) Towed in-water devices. For towed in-water devices:
(A) Mitigation zones and requirements. During the use of in-water
devices towed by an aircraft, a manned surface vessel, or an Unmanned
Surface Vehicle or Unmanned Underwater Vehicle already being escorted
(and operated under positive control) by a crewed surface vessel, the
following mitigation zone requirements apply:
(1) Manned towing platforms, or surface support vessels already
participating in the event that have positive control over an unmanned
vehicle that is towing an in-water device, must maneuver itself or the
unmanned vehicle (which may include reducing speed) to ensure towed in-
water devices maintain the following distances as mission and
circumstances allow:
(i) 250 yd (228.6 m) from marine mammals.
(ii) [Reserved]
(2) [Reserved]
(B) Lookout requirements. The following Lookout requirements apply:
(1) One Lookout on the manned towing vessel, or on a surface
support

[[Page 20072]]

vessel that is already participating in the event and has positive
control over an unmanned vehicle that is towing an in-water device.
(2) [Reserved]
(C) Mitigation zone observation. Action Proponent personnel must
observe the mitigation zones in accordance with the following:
(1) Action Proponent personnel must observe the mitigation zone for
marine mammals immediately prior to and while in-water devices are
being towed.
(2) [Reserved]
(xxi) Commencement or recommencement conditions. Action Proponents
must not commence or recommence an activity after a marine mammal is
observed within a relevant mitigation zone until one of the following
conditions has been met:
(A) Observed exiting. A Lookout observes the animal exiting the
mitigation zone;
(B) Concluded to have exited. A Lookout concludes that the animal
has exited the mitigation zone based on its observed course, speed, and
movement relative to the mitigation zone;
(C) Clear from additional sightings. A Lookout affirms the
mitigation zone has been clear from additional sightings for the
activity-specific wait period; or
(D) Stressor transit. For mobile events, the stressor has transited
a distance equal to double the mitigation zone size beyond the location
of the last sighting.
(xxii) Exceptions to activity-based mitigation. Activity-based
mitigation for acoustic stressors will not apply to:
(A) Sources not operated under positive control (e.g., moored
oceanographic sources);
(B) Sources used for safety of navigation (e.g., fathometers);
(C) Sources used or deployed by aircraft operating at high
altitudes (e.g., bombs deployed from high altitude (since personnel
cannot effectively observe the surface of the water));
(D) Sources used, deployed, or towed by unmanned platforms except
when escort vessels are already participating in the event and have
positive control over the source;
(E) Sources used by submerged submarines (e.g., sonar (since they
cannot conduct visual observation));
(F) De minimis sources (e.g., those >200 kHz);
(G) Long-duration sources, including those used for acoustic and
oceanographic research; and
(H) Vessel-based, unmanned vehicle-based, or towed in-water sources
when marine mammals (e.g., dolphins) are determined to be intentionally
swimming at the bow or alongside or directly behind the vessel,
vehicle, or device (e.g., to bow-ride or wake-ride).
(2) Geographic mitigation areas. The Action Proponents must
implement the geographic mitigation requirements described in
paragraphs (a)(2)(i) through (a)(2)(viii) of this section.
(i) Ship shock trial mitigation area. Figure 1 to this paragraph
(a)(2) shows the location of the mitigation areas. Within the ship
shock trial mitigation areas, the following requirements apply:
(A) Jacksonville Operating Area. Navy personnel must not conduct
ship shock trials within the portion of the ship shock trial box that
overlaps the Jacksonville Operating Area from November 15 through April
15.
(B) Pre-event planning. Pre-event planning for ship shock trials
must include the selection of one primary and two secondary sites
(within one of the ship shock trial boxes) where marine mammal
abundance is expected to be the lowest during an event, with the
primary and secondary locations located more than 2 nmi (3.7 km) from
the western boundary of the Gulf Stream for events planned within the
portion of the ship shock trial box that overlaps the Jacksonville
Operating Area.
(C) Environmentally unsuitable site. If Action Proponent personnel
determine during pre-event visual observations that the primary site is
environmentally unsuitable (e.g., continuous observations of marine
mammals), personnel must evaluate the potential to move the event to
one of the secondary sites as described in the LOAs.
(ii) Major training exercise planning awareness mitigation areas.
Figure 1 to this paragraph (a)(2) shows the location of the mitigation
area. Within the major training exercise planning awareness mitigation
areas, the following requirements apply:
(A) Northeast. Within Major Training Exercise Planning Awareness
Mitigation Areas located in the Northeast (i.e., the combined areas
within the Gulf of Maine, over the continental shelves off Long Island,
Rhode Island, Massachusetts, and Maine), the Action Proponents must not
conduct any full or partial Major Training Exercises (MTEs).
(B) Mid-Atlantic. Within Major Training Exercise Planning Awareness
Mitigation Areas located in the Mid-Atlantic (i.e., the combined areas
off Maryland, Delaware, and North Carolina), the Action Proponents must
not conduct any full or partial MTEs to the maximum extent practical,
and must not conduct more than four full or partial MTEs per year.
(iii) Northeast North Atlantic right whale mitigation area. Figure
1 to this paragraph (a)(2) shows the location of the mitigation area.
Within the northeast North Atlantic right whale mitigation area, the
following requirements apply:
(A) Active sonar. The Action Proponents must minimize the use of
low-frequency active sonar, mid-frequency active sonar, and high-
frequency active sonar in the mitigation area to the maximum extent
practical.
(B) In-water explosives. The Action Proponents must not detonate
in-water explosives (including underwater explosives and explosives
deployed against surface targets) within the mitigation area.
(C) Explosive sonobuoys. The Action Proponents must not detonate
explosive sonobuoys within 3 nmi (5.6 km) of the mitigation area.
(D) Non-explosive bombs. The Action Proponents must not use non-
explosive bombs within the mitigation area.
(E) Non-explosive torpedoes. During non-explosive torpedoes events
within the mitigation area:
(1) The Action Proponents must conduct activities during daylight
hours in Beaufort sea state 3 or less;
(2) The Action Proponents must post two Lookouts in an aircraft
during dedicated aerial surveys, and one Lookout on the submarine
participating in the event (when surfaced), in addition to Lookouts
required as described in Sec. 218.84(a)(1)(xvii).
(i) Lookouts must begin conducting visual observations immediately
prior to the start of an event.
(ii) If floating vegetation or marine mammals are observed in the
event vicinity, the event must not commence until the vicinity is clear
or the event is relocated to an area where the vicinity is clear.
(iii) Lookouts must continue to conduct visual observations during
the event.
(iv) If marine mammals are observed in the vicinity, the event must
cease until one of the commencement or recommencement conditions in
Sec. 218.84(a)(1)(xxi) is met.
(3) During transits and normal firing, surface ships must maintain
a speed of no more than 10 knots (kn; 18.5 kilometer/hour (km/hr));
during submarine target firing, surface ships must maintain speeds of
no more than 18 kn (33.3 km/hr); and during vessel target firing,
surface ship speeds may exceed 18 kn (33.3 km/hr) for brief periods of
time (e.g., 10-15 minutes).
(F) Vessel transits. For vessel transits within the mitigation
area:
(1) The Action Proponents must conduct a web query or email inquiry
to the North Atlantic Right Whale Sighting Advisory System or WhaleMap
(https://whalemap.org/) to obtain the latest North Atlantic right whale
sightings

[[Page 20073]]

data prior to transiting the mitigation area.
(2) The Action Proponents must provide Lookouts the sightings data
prior to standing watch. Lookouts must use that data to help inform
visual observations during vessel transits.
(G) Speed reductions. Surface ships must implement speed reductions
after observing a North Atlantic right whale, if transiting within 5
nmi (9.3 km) of a sighting reported to the North Atlantic Right Whale
Sighting Advisory System within the past week, and when transiting at
night or during periods of reduced visibility.
(iv) Gulf of Maine marine mammal mitigation area. Figure 1 to this
paragraph (a)(2) shows the location of the mitigation area. Within the
Gulf of Maine marine mammal mitigation area, the following requirements
apply:
(A) Surface ship hull-mounted mid-frequency active sonar. The
Action Proponents must not use more than 200 hours of surface ship
hull-mounted mid-frequency active sonar annually within the mitigation
area.
(B) [Reserved]
(v) Jacksonville Operating Area North Atlantic right whale
mitigation area. Figure 1 to this paragraph (a)(2) shows the location
of the mitigation area. Within the Jacksonville Operating Area North
Atlantic right whale mitigation area, the following requirements apply:
(A) November 15 to April 15. From November 15 to April 15 within
the mitigation area, prior to vessel transits or military readiness
activities involving active sonar, in-water explosives (including
underwater explosives and explosives deployed against surface targets),
or non-explosive ordnance deployed against surface targets (including
aerial-deployed mines), the Action Proponents must initiate
communication with Fleet Area Control and Surveillance Facility,
Jacksonville to obtain Early Warning System data. The facility must
advise of all reported North Atlantic right whale sightings in the
vicinity of planned vessel transits and military readiness activities.
Sightings data must be used when planning event details (e.g., timing,
location, duration) to minimize impacts to North Atlantic right whale
to the maximum extent practical.
(B) Sightings data to Lookouts. Action Proponent personnel must
provide the sightings data to Lookouts prior to standing watch to help
inform visual observations.
(vi) Southeast North Atlantic right whale mitigation area. Figure 1
to this paragraph (a)(2) shows the location of the mitigation area.
Within the Southeast North Atlantic right whale mitigation area, the
following requirements apply:
(A) Helicopter dipping sonar and low-frequency or surface ship
hull-mounted mid-frequency active sonar during navigation training or
object detection. From November 15 to April 15 within the mitigation
area, to the maximum extent practical, the Action Proponents must
minimize use of helicopter dipping sonar (a mid-frequency active sonar
source) and low-frequency or surface ship hull-mounted mid-frequency
active sonar during navigation training or object detection.
(B) All other high-frequency, mid-frequency, or low-frequency
active sonars. From November 15 to April 15 within the mitigation area,
the Action Proponents must not use high-frequency active sonar; or low-
frequency or mid-frequency active sonar with the exception of the
sources listed in paragraph (a)(2)(vi)(A) of this section in accordance
with that paragraph.
(C) Explosives. From November 15 to April 15 within the mitigation
area, the Action Proponents must not detonate in-water explosives
(including underwater explosives and explosives deployed against
surface targets).
(D) Physical disturbance. From November 15 to April 15 within the
mitigation area, the Action Proponents must not deploy non-explosive
ordnance against surface targets (including aerial-deployed mines).
(E) Vessel strike. From November 15 to April 15 within the
mitigation area, surface ships must minimize north-south transits to
the maximum extent practical, and must implement speed reductions to
the maximum extent practicable after they observe a North Atlantic
right whale, if they are within 5 nmi (9.3 km) of an Early Warning
System sighting reported within the past 12 hours, and at night and in
poor visibility.
(F) Acoustic, explosives, and physical disturbance and vessel
strike. From November 15 to April 15 within the mitigation area, prior
to vessel transits or military readiness activities involving active
sonar, in-water explosives (including underwater explosives and
explosives deployed against surface targets), or non-explosive ordnance
deployed against surface targets (including aerial-deployed mines), the
Action Proponents must initiate communication with Fleet Area Control
and Surveillance Facility, Jacksonville to obtain Early Warning System
sightings data. The facility must advise of all reported North Atlantic
right whale sightings in the vicinity of planned vessel transits and
military readiness activities. The Action Proponents must provide
Lookouts the sightings data prior to standing watch to help inform
visual observations.
(vii) Dynamic North Atlantic right whale mitigation areas. The
applicable dates and locations of this mitigation area must correspond
with NMFS' Dynamic Management Areas, which vary throughout the year
based on the locations and timing of confirmed North Atlantic right
whale detections. Within the Dynamic North Atlantic right whale
mitigation areas, the following requirements apply:
(A) North Atlantic right whale Dynamic Management Area
notifications. The Action Proponents must provide North Atlantic right
whale Dynamic Management Area information (e.g., location and dates) to
applicable assets transiting and training or testing in the vicinity of
the Dynamic Management Area. The broadcast awareness notification
messages must alert assets (and their Lookouts) to the possible
presence of North Atlantic right whale in their vicinity.
(B) Visual observations. Lookouts must use the information to help
inform visual observations during military readiness activities that
involve vessel movements, active sonar, in-water explosives (including
underwater explosives and explosives deployed against surface targets),
or non-explosive ordnance deployed against surface targets in the
mitigation area.
(viii) Rice's whale mitigation area. Figure 1 to this paragraph
(a)(2) shows the location of the mitigation area. Within the Rice's
whale mitigation area, the following requirements apply:
(A) Surface ship mid-frequency active sonar. The Action Proponents
must not use more than 200 hours of surface ship hull-mounted mid-
frequency active sonar annually within the mitigation area.
(B) Explosives. The Action Proponents must not detonate in-water
explosives (including underwater explosives and explosives deployed
against surface targets) within the mitigation area, except during mine
warfare activities.
(ix) National Security Requirement. Should national security
require the Action Proponents to exceed a requirement in paragraphs
(a)(2)(i) through (a)(2)(viii) of this section, Action Proponent
personnel must provide NMFS with advance notification and include the
information (e.g., sonar hours, explosives usage, or restricted area
use) in its annual activity reports submitted to NMFS
BILLING CODE 3510-22-P

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(b) [Reserved]

Sec. 218.85 Requirements for monitoring and reporting.

The Action Proponents must implement the following monitoring and
reporting requirements when conducting the specified activities:
(a) Notification of take. Action proponent personnel must notify
NMFS immediately (or as soon as operational security considerations
allow) if the specified activity identified in Sec. 218.80 is thought
to have resulted in the mortality or serious injury of any marine
mammals, or in any Level A harassment or Level B harassment of marine
mammals not identified in this subpart.
(b) Monitoring and reporting under the LOAs. The Action Proponents
must conduct all monitoring and reporting required under the LOAs.
(c) Notification of injured, live stranded, or dead marine mammals.
Action Proponent personnel must abide by the Notification and Reporting
Plan, which sets out notification, reporting, and other requirements
when dead, injured, or live stranded marine mammals are detected. The
Notification and Reporting Plan is available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.
(d) Annual AFTT Study Area marine species monitoring report. The
Action Proponents must submit an annual AFTT Study Area marine species
monitoring report describing the implementation and results from the
previous calendar year. Data collection methods will be standardized
across range complexes and the AFTT Study Area to allow for comparison
in different geographic locations. The draft report must be submitted
to the Director, Office of Protected Resources, NMFS, annually. NMFS
will submit comments or questions on the report, if any, within 3
months of receipt. The report will be considered final after the Action
Proponents have addressed NMFS' comments, or 3 months after submittal
of the draft if NMFS does not provide comments on the draft report. The
report must describe progress of knowledge made with respect to
intermediate scientific objectives within the AFTT Study Area
associated with the Integrated Comprehensive Monitoring Program (ICMP).
Similar study questions must be treated together so that progress on
each topic can be summarized across all Navy ranges. The report need
not include analyses and content that do not provide direct assessment
of cumulative progress on the monitoring plan study questions.
(e) Quick look reports. In the event that the sound levels analyzed
in promulgation of these regulations were exceeded within a given
reporting year, the Action Proponents must submit a preliminary
report(s) detailing the exceedance within 21 days after the anniversary
date of issuance of the LOAs.
(f) Annual AFTT Training and Testing Reports. Regardless of whether
analyzed sound levels were exceeded, the Navy must submit a detailed
report (AFTT Annual Training Exercise Report and Testing Activity
Report) and the Coast Guard must submit a detailed report (AFTT Annual
Training Exercise Report) to the Director, Office of Protected
Resources, NMFS annually. NMFS will submit comments or questions on the
reports, if any, within 1 month of receipt. The reports will be
considered final after the Action Proponents have addressed NMFS'
comments, or 1 month after submittal of the drafts if NMFS does not
provide comments on the draft reports. The annual reports must contain
a summary of all sound sources used (total hours or quantity (per the
LOAs) of each bin of sonar or other non-impulsive source; total annual
number of each type of explosive exercises; and total annual expended/
detonated rounds (missiles, bombs, sonobuoys, etc.) for each explosive
bin). The annual reports must also contain cumulative sonar and
explosive use quantity from previous years' reports through the current
year. Additionally, if there were any changes to the sound source
allowance in the reporting year, or cumulatively, the reports would
include a discussion of why the change was made and include analysis to
support how the change did or did not affect the analysis in the 2024
AFTT Draft Supplemental EIS/OEIS and MMPA final rule. The annual
reports must also include the details regarding specific requirements
associated with the mitigation areas listed in paragraph (f)(4) of this
section. The analysis in the detailed report must be based on the
accumulation of data from the current year's report and data collected
from previous annual reports. The final annual/close-out report at the
conclusion of the authorization period (year 7) will also serve as the
comprehensive close-out report and include both the final year annual
incidental take compared to annual authorized incidental take as well
as a cumulative 7-year incidental take compared to 7-year authorized
incidental take. The AFTT Annual Training and Testing Reports must
include the specific information described in the LOAs.
(1) MTEs. This section of the report must contain the following
information for MTEs conducted in the AFTT Study Area.
(i) Exercise information (for each MTE). For exercise information
(for each MTE):
(A) Exercise designator.
(B) Date that exercise began and ended.
(C) Location.
(D) Number and types of active sonar sources used in the exercise.
(E) Number and types of passive acoustic sources used in exercise.
(F) Number and types of vessels, aircraft, and other platforms
participating in each exercise.
(G) Total hours of all active sonar source operation.
(H) Total hours of each active sonar source bin.
(I) Wave height (high, low, and average) during exercise.
(ii) Individual marine mammal sighting information for each
sighting in each exercise where mitigation was implemented. For
individual marine mammal sighting information for each sighting in each
exercise where mitigation was implemented:
(A) Date, time, and location of sighting.
(B) Species (if not possible, indication of whale/dolphin/
pinniped).
(C) Number of individuals.
(D) Initial Detection Sensor (e.g., passive sonar, Lookout).
(E) Indication of specific type of platform observation was made
from (including, for example, what type of surface vessel or testing
platform).
(F) Length of time observers maintained visual contact with marine
mammal.
(G) Sea state.
(H) Visibility.
(I) Sound source in use at the time of sighting.
(J) Indication of whether animal was less than 200 yd (182.9 m),
200 to 500 yd (182.9 to 457.2 m), 500 to 1,000 yd (457.2 m to 914.4 m),
1,000 to 2,000 yd (914.4 m to 1,828.8 m), or greater than 2,000 yd
(1,828.8 m) from sonar source.
(K) Whether operation of sonar sensor was delayed, or sonar was
powered or shut down, and the length of the delay.
(L) If source in use was hull-mounted, true bearing of animal from
the vessel, true direction of vessel's travel, and estimation of
animal's motion relative to vessel (opening, closing, parallel).
(M) Lookouts must report, in plain language and without trying to
categorize in any way, the observed behavior of the animal(s) (such as

[[Page 20076]]

animal closing to bow ride, paralleling course/speed, floating on
surface and not swimming, etc.) and if any calves were present.
(iii) An evaluation (based on data gathered during all of the MTEs)
of the effectiveness of mitigation measures designed to minimize the
received level to which marine mammals may be exposed. For an
evaluation (based on data gathered during all of the MTEs) of the
effectiveness of mitigation measures designed to minimize the received
level to which marine mammals may be exposed:
(A) This evaluation must identify the specific observations that
support any conclusions the Navy reaches about the effectiveness of the
mitigation.
(B) [Reserved]
(2) Sinking Exercises. This section of the report must include the
following information for each SINKEX completed that year in the AFTT
Study Area:
(i) Exercise information. For exercise information:
(A) Location.
(B) Date and time exercise began and ended.
(C) Total hours of observation by Lookouts before, during, and
after exercise.
(D) Total number and types of explosive source bins detonated.
(E) Number and types of passive acoustic sources used in exercise.
(F) Total hours of passive acoustic search time.
(G) Number and types of vessels, aircraft, and other platforms
participating in exercise.
(H) Wave height in feet (high, low, and average) during exercise.
(I) Narrative description of sensors and platforms utilized for
marine mammal detection and timeline illustrating how marine mammal
detection was conducted.
(ii) Individual marine mammal observation (by Action Proponent
Lookouts) information for each sighting where mitigation was
implemented. For individual marine mammal observation (by Action
Proponent Lookouts) information for each sighting where mitigation was
implemented:
(A) Date/Time/Location of sighting.
(B) Species (if not possible, indicate whale, dolphin, or
pinniped).
(C) Number of individuals.
(D) Initial detection sensor (e.g., sonar or Lookout).
(E) Length of time observers maintained visual contact with marine
mammal.
(F) Sea state.
(G) Visibility.
(H) Whether sighting was before, during, or after detonations/
exercise, and how many minutes before or after.
(I) Distance of marine mammal from actual detonations (or target
spot if not yet detonated): Less than 200 yd (182.9 m), 200 to 500 yd
(182.9 to 457.2 m), 500 to 1,000 yd (457.2 m to 914.4 m), 1,000 to
2,000 yd (914.4 m to 1,828.8 m), or greater than 2,000 yd (1,828.8 m).
(J) Lookouts must report, in plain language and without trying to
categorize in any way, the observed behavior of the animal(s) (such as
animal closing to bow ride, paralleling course/speed, floating on
surface and not swimming etc.), including speed and direction and if
any calves were present.
(K) The report must indicate whether explosive detonations were
delayed, ceased, modified, or not modified due to marine mammal
presence and for how long.
(L) If observation occurred while explosives were detonating in the
water, indicate munition type in use at time of marine mammal
detection.
(3) Summary of sources used. This section of the report must
include the following information summarized from the authorized sound
sources used in all training and testing events:
(i) Totals for sonar or other acoustic source bins. Total annual
hours or quantity (per the LOA) of each bin of sonar or other acoustic
sources (e.g., pile driving and air gun activities); and
(ii) Total for explosive bins. Total annual expended/detonated
ordnance (missiles, bombs, sonobuoys, etc.) for each explosive bin.
(4) Special reporting for geographic mitigation areas. This section
of the report must contain the following information for activities
conducted in geographic mitigation areas in the AFTT Study Area:
(i) Northeast North Atlantic Right Whale Mitigation Area. The
Action Proponents must report the total annual hours and counts of
active sonar and in-water explosives (including underwater explosives
and explosives deployed against surface targets) used in the mitigation
area.
(ii) Gulf of Maine Marine Mammal Mitigation Area. The Action
Proponents must report the total annual hours and counts of active
sonar and in-water explosives (including underwater explosives and
explosives deployed against surface targets) used in the mitigation
area.
(iii) Southeast North Atlantic Right Whale Mitigation Area. The
Action Proponents must report the total annual hours and counts of
active sonar and in-water explosives (including underwater explosives
and explosives deployed against surface targets) used in the mitigation
area from November 15 to April 15.
(iv) Southeast North Atlantic Right Whale Special Reporting
Mitigation Area. The Action Proponents must report the total annual
hours and counts of active sonar and in-water explosives (including
underwater explosives and explosives deployed against surface targets)
used within the mitigation area from November 15 to April 15.
(v) Rice's Whale Mitigation Area. The Action Proponents must report
the total annual hours and counts of active sonar and in-water
explosives (including underwater explosives and explosives deployed
against surface targets) used in the mitigation area.
(vi) National security requirement. If an Action Proponent(s)
evokes the national security requirement described in Sec.
218.84(a)(2)(ix), the Action Proponent personnel must include
information about the event in its Annual AFTT Training and Testing
Report.
(g) MTE sonar exercise notification. The Action Proponents must
submit to NMFS (contact as specified in the LOAs) an electronic report
within 15 calendar days after the completion of any MTE indicating:
(1) Location. Location of the exercise;
(2) Dates. Beginning and end dates of the exercise; and
(3) Type. Type of exercise.

Sec. 218.86 Letters of Authorization.

(a) To incidentally take marine mammals pursuant to this subpart,
the Action Proponents must apply for and obtain LOAs.
(b) An LOA, unless suspended or revoked, may be effective for a
period of time not to exceed the expiration date of this subpart.
(c) In the event of projected changes to the activity or to
mitigation, monitoring, or reporting measures (excluding changes made
pursuant to the adaptive management provision of Sec. 218.87(c)(1))
required by an LOA, the Action Proponent must apply for and obtain a
modification of the LOA as described in Sec. 218.87.
(d) Each LOA will set forth:
(1) Permissible methods of incidental taking;
(2) Geographic areas for incidental taking;
(3) Means of effecting the least practicable adverse impact (i.e.,
mitigation) on the species and stocks of marine mammals and their
habitat; and
(4) Requirements for monitoring and reporting.
(e) Issuance of the LOA(s) must be based on a determination that
the level of taking is consistent with the findings

[[Page 20077]]

made for the total taking allowable under the regulations of this
subpart.
(f) Notice of issuance or denial of the LOA(s) will be published in
the Federal Register within 30 days of a determination.

Sec. 218.87 Modifications of Letters of Authorization.

(a) An LOA issued under Sec. Sec. 216.106 of this chapter and
218.86 for the activity identified in Sec. 218.80(c) shall be
modified, upon request by the LOA Holder, provided that:
(1) The specified activity and mitigation, monitoring, and
reporting measures, as well as the anticipated impacts, are the same as
those described and analyzed for the regulations in this subpart
(excluding changes made pursuant to the adaptive management provision
in paragraph (c)(1) of this section); and
(2) NMFS determines that the mitigation, monitoring, and reporting
measures required by the previous LOAs under this subpart were
implemented.
(b) For LOA modification requests by the applicants that include
changes to the activity or to the mitigation, monitoring, or reporting
measures (excluding changes made pursuant to the adaptive management
provision in paragraph (c)(1) of this section), the LOA should be
modified provided that:
(1) NMFS determines that the change(s) to the activity or the
mitigation, monitoring or reporting do not change the findings made for
the regulations and do not result in more than a minor change in the
total estimated number of takes (or distribution by species or stock or
years), and
(2) NMFS may publish a notice of proposed modified LOA in the
Federal Register, including the associated analysis of the change, and
solicit public comment before issuing the LOA.
(c) An LOA issued under Sec. Sec. 216.106 and 218.86 of this
chapter for the activities identified in Sec. 218.80(c) may be
modified by NMFS Office of Protected Resources under the following
circumstances:
(1) After consulting with the Action Proponents regarding the
practicability of the modifications, through adaptive management, NMFS
may modify (including remove, revise or add to) the existing
mitigation, monitoring, or reporting measures if doing so creates a
reasonable likelihood of more effectively accomplishing the goals of
the mitigation and monitoring measures set forth in this subpart.
(i) Possible sources of data that could contribute to the decision
to modify the mitigation, monitoring, or reporting measures in an LOA
include, but are not limited to:
(A) Results from the Action Proponents' monitoring report and
annual exercise reports from the previous year(s);
(B) Results from other marine mammal and/or sound research or
studies; or
(C) Any information that reveals marine mammals may have been taken
in a manner, extent, or number not authorized by this subpart or
subsequent LOAs.
(ii) If, through adaptive management, the modifications to the
mitigation, monitoring, or reporting measures are substantial, NMFS
shall publish a notice of proposed LOA(s) in the Federal Register and
solicit public comment.
(2) If the NMFS Office of Protected Resources determines that an
emergency exists that poses a significant risk to the well-being of the
species or stocks of marine mammals specified in LOAs issued pursuant
to Sec. Sec. 216.106 of this chapter and 218.86, a LOA may be modified
without prior notice or opportunity for public comment. Notice would be
published in the Federal Register within 30 days of the action.

Sec. Sec. 218.88-218.89 [Reserved]

[FR Doc. 2025-07780 Filed 5-8-25; 8:45 am]
BILLING CODE 3510-22-P