[Federal Register Volume 88, Number 2 (Wednesday, January 4, 2023)]
[Rules and Regulations]
[Pages 604-697]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-27951]



[[Page 603]]

Vol. 88

Wednesday,

No. 2

January 4, 2023

Part III





Department of Commerce





-----------------------------------------------------------------------





 National Oceanic and Atmospheric Administration





-----------------------------------------------------------------------





50 CFR Part 218





Taking and Importing Marine Mammals; Taking Marine Mammals Incidental 
to the U.S. Navy Training Activities in the Gulf of Alaska Study Area; 
Final Rule

  Federal Register / Vol. 88 , No. 2 / Wednesday, January 4, 2023 / 
Rules and Regulations  

[[Page 604]]


-----------------------------------------------------------------------

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 218

[Docket No. 221219-0277]
RIN 0648-BK46


Taking and Importing Marine Mammals; Taking Marine Mammals 
Incidental to the U.S. Navy Training Activities in the Gulf of Alaska 
Study Area

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

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: NMFS, upon request from the U.S. Navy (Navy), issues these 
regulations pursuant to the Marine Mammal Protection Act (MMPA) to 
govern the taking of marine mammals incidental to the training 
activities conducted in the Gulf of Alaska (GOA) Study Area. The Navy's 
activities qualify as military readiness activities pursuant to the 
MMPA, as amended by the National Defense Authorization Act for Fiscal 
Year 2004 (2004 NDAA). These regulations, which allow for the issuance 
of Letters of Authorization (LOA) for the incidental take of marine 
mammals during the described activities and timeframes, prescribe the 
permissible methods of taking and other means of effecting the least 
practicable adverse impact on marine mammal species and their habitat, 
and establish requirements pertaining to the monitoring and reporting 
of such taking.

DATES: Effective February 3, 2023 through February 2, 2030.

ADDRESSES: A copy of the Navy's application, NMFS' proposed and final 
rules and subsequent LOAs for the existing regulations, and other 
supporting documents and documents cited herein may be obtained online 
at www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities. In case of problems 
accessing these documents, please use the contact listed here (see FOR 
FURTHER INFORMATION CONTACT).

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

SUPPLEMENTARY INFORMATION:

Purpose of Regulatory Action

    These regulations, issued under the authority of the MMPA (16 
U.S.C. 1361 et seq.), provide the framework for authorizing the take of 
marine mammals incidental to the Navy's training activities (which 
qualify as military readiness activities) including the use of sonar 
and other transducers, and in-air detonations at or near the surface 
(within 10 m above the water surface) in the GOA Study Area. The GOA 
Study Area is comprised of three areas: the Temporary Maritime 
Activities Area (TMAA), a warning area, and the Western Maneuver Area 
(WMA) (see Figure 1). The TMAA and WMA are temporary areas established 
within the GOA for ships, submarines, and aircraft to conduct training 
activities. The warning area overlaps and extends slightly beyond the 
northern corner of the TMAA. The WMA is located south and west of the 
TMAA and provides additional surface, sub-surface, and airspace in 
which to maneuver in support of activities occurring within the TMAA. 
The use of sonar and other transducers, and explosives would not occur 
within the WMA.
    NMFS received an application from the Navy requesting 7-year 
regulations and an authorization to incidentally take individuals of 
multiple species of marine mammals (Navy's rulemaking/LOA application 
or Navy's application). Take is anticipated to occur by Level A 
harassment and Level B harassment incidental to the Navy's training 
activities. No lethal take is anticipated or proposed for 
authorization.
    Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs 
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, after notice and public comment, the agency makes certain findings 
and issues regulations that set forth permissible methods of taking 
pursuant to that activity, as well as monitoring and reporting 
requirements. Section 101(a)(5)(A) of the MMPA and the implementing 
regulations at 50 CFR part 216, subpart I, provide the legal basis for 
issuing this final rule and the subsequent LOAs. As directed by this 
legal authority, this final rule contains mitigation, monitoring, and 
reporting requirements.
    The 2004 NDAA (Pub. L. 108-136) removed the ``small numbers'' and 
``specified geographical region'' limitations indicated above and 
amended the definition of ``harassment'' as applied to a ``military 
readiness activity.'' The activity for which incidental take of marine 
mammals is being requested addressed here qualifies as a military 
readiness activity.

Summary of Major Provisions Within the Final Rule

    The following is a summary of the primary provisions of this final 
rule regarding the Navy's activities. These provisions include, but are 
not limited to:
     The use of defined powerdown and shutdown zones (based on 
activity);
     Measures to reduce the likelihood of ship strikes;
     Activity limitations in certain areas and times that are 
biologically important (e.g., for foraging or migration) for marine 
mammals;
     Implementation of a Notification and Reporting Plan (for 
dead or live stranded marine mammals); and
     Implementation of a robust monitoring plan to improve our 
understanding of the environmental effects resulting from the Navy 
training activities.
    Additionally, the rule includes an adaptive management component 
that allows for timely modification of mitigation or monitoring 
measures based on new information, when appropriate.

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA 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 issued or, if the taking 
is limited to harassment, a notice of proposed authorization is 
provided to the public for review and the opportunity to submit 
comments.
    An authorization for incidental takings shall be granted if NMFS 
finds that the taking will have a negligible impact on the species or 
stocks and will not have an unmitigable adverse impact on the 
availability of the species or stocks for taking for subsistence uses 
where relevant, including by Alaska Natives. Further, NMFS must 
prescribe the permissible methods of taking and 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

[[Page 605]]

(referred to in this rule as ``mitigation measures''); and requirements 
pertaining to the monitoring and reporting of such 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 Analysis and 
Negligible Impact Determination section below discusses the definition 
of ``negligible impact.''
    The NDAA for Fiscal Year 2004 (2004 NDAA) (Pub. L. 108-136) amended 
section 101(a)(5) of the MMPA to remove the ``small numbers'' and 
``specified geographical region'' provisions indicated above and 
amended the definition of ``harassment'' as applied to a ``military 
readiness activity.'' The definition of harassment for military 
readiness activities (Section 3(18)(B) of the MMPA) is (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 such behavioral patterns are 
abandoned or significantly altered (Level B harassment). In addition, 
the 2004 NDAA amended the MMPA as it relates to military readiness 
activities such that the least practicable adverse impact analysis 
shall include consideration of personnel safety, practicality of 
implementation, and impact on the effectiveness of the military 
readiness activity.
    More recently, Section 316 of the NDAA for Fiscal Year 2019 (2019 
NDAA) (Pub. L. 115-232), signed on August 13, 2018, amended the MMPA to 
allow incidental take rules for military readiness activities under 
section 101(a)(5)(A) to be issued for up to 7 years. Prior to this 
amendment, all incidental take rules under section 101(a)(5)(A) were 
limited to 5 years.

Summary and Background of Request

    On October 9, 2020, NMFS received an adequate and complete 
application from the Navy requesting authorization for take of marine 
mammals, by Level A harassment and Level B harassment, incidental to 
training from the use of active sonar and other transducers and 
explosives (in-air, occurring at or above the water surface) in the 
TMAA over a 7-year period. On March 12, 2021, the Navy submitted an 
updated application that provided revisions to the Northern fur seal 
take estimate and incorporated additional best available science. In 
August 2021, the Navy communicated to NMFS that it was considering an 
expansion of the GOA Study Area and an expansion of the Portlock Bank 
Mitigation Area proposed in its previous applications. On February 2, 
2022, the Navy submitted a second updated application that described 
the addition of the WMA to the GOA Study Area (which previously just 
consisted of the TMAA) and the replacement of the Portlock Bank 
Mitigation Area with the Continental Shelf and Slope Mitigation Area. 
The GOA Study Area supports opportunistic experimentation and testing 
activities when conducted as part of training activities and when 
considered to be consistent with the proposed training activities. 
These activities could occur as part of large-scale exercises or as 
independent events. Therefore, there is no separate discussion or 
analysis for testing activities that may occur as part of the proposed 
military readiness activities in the GOA Study Area.
    On January 8, 2021 (86 FR 1483), we published a notice of receipt 
(NOR) of application in the Federal Register, requesting comments and 
information related to the Navy's request for 30 days. We received one 
comment on the NOR that was non-substantive in nature. On August 11, 
2022, we published a notice of proposed rulemaking (87 FR 49656) and 
requested comments and information related to the Navy's request for 45 
days. All substantive comments received during the NOR and the proposed 
rulemaking comment periods were considered in developing this final 
rule. Comments received on the proposed rule are addressed in this 
final rule in the Comments and Responses section.
    The following types of training, which are classified as military 
readiness activities pursuant to the MMPA, as amended by the 2004 NDAA, 
will be covered under the regulations and LOA, if issued: Surface 
Warfare (detonations at or above the water surface) and Anti-Submarine 
Warfare (sonar and other transducers). The Navy is also conducting Air 
Warfare, Electronic Warfare, Naval Special Warfare, Strike Warfare, and 
Support Operations, but these activities do not involve sonar and other 
transducers, detonations at or above the water surface, or any other 
stressors that could result in the take of marine mammals. (See the 
2022 GOA Final Supplemental Environmental Impact Statement (FSEIS)/
Overseas Environmental Impact Statement (OEIS) (2022 GOA FSEIS/OEIS) 
for more detail on those activities.) The activities will not include 
in-water explosives, pile driving/removal, or use of air guns.
    This is the third time NMFS has promulgated incidental take 
regulations pursuant to the MMPA relating to similar military readiness 
activities in the GOA, following regulations that were effective 
beginning May 4, 2011 (76 FR 25479; May 4, 2011) and April 26, 2017 (82 
FR 19530; April 27, 2017). For this third round of rulemaking, the 
activities the Navy is planning to conduct are largely a continuation 
of ongoing activities conducted for more than a decade. While the 
specified activities have not changed, there are changes in the 
platforms and systems used in those activities, as well as changes in 
the bins (source classifications) used to analyze the activities. For 
example, two new sonar bins were added (MF12 and ASW1) and another bin 
was eliminated (HF6). This was due to changes in platforms and systems. 
Further, the Navy expanded the GOA Study Area to include the WMA, 
though the vast majority of the training activities will still occur 
only in the TMAA.
    The Navy's mission is to organize, train, equip, and maintain 
combat-ready naval forces capable of winning wars, deterring 
aggression, and maintaining freedom of the seas. This mission is 
mandated by Federal law (10 U.S.C. 8062), which requires the readiness 
of the naval forces of the United States. The Navy executes this 
responsibility by establishing and executing training programs, 
including at-sea training and exercises, and ensuring naval forces have 
access to the ranges, operating areas (OPAREA), and airspace needed to 
develop and maintain skills for conducting naval activities.
    The Navy has conducted training activities in the TMAA portion of 
the GOA Study Area since the 1990s. Since the 1990s, the Department of 
Defense has conducted a major joint training exercise in Alaska and off 
the Alaskan coast that involves the Departments of the Navy, Army, Air 
Force, and Coast Guard participants reporting to a unified or joint 
commander who coordinates the activities. These activities are planned 
to demonstrate and evaluate the ability of the services to engage in a 
conflict and successfully carry out plans in response to a threat to 
national security. The Navy's planned activities for the period of 
these regulations would be a continuation of the types and level of 
training activities that have been ongoing for more than a decade.
    The Navy's rulemaking/LOA application reflects the most up-to-date 
compilation of training activities deemed necessary by senior Navy 
leadership to accomplish military readiness requirements. The types and

[[Page 606]]

numbers of activities included in the rule account for fluctuations in 
training in order to meet evolving or emergent military readiness 
requirements. These regulations cover training activities that will 
occur for a 7-year period beginning February 3, 2023.

Description of the Specified Activity

    A detailed description of the specified activity was provided in 
our Federal Register notice of proposed rulemaking (87 FR 49656; August 
11, 2022); please see that notice of proposed rulemaking or the Navy's 
application for more information. The Navy requested authorization to 
take marine mammals incidental to conducting training activities. The 
Navy has determined that acoustic and explosive (in-air, occurring at 
or above the water surface) stressors are most likely to result in 
impacts on marine mammals that could rise to the level of harassment, 
and NMFS concurs with this determination. Descriptions of these 
activities are provided in section 2 of the 2022 GOA FSEIS/OEIS (U.S. 
Department of the Navy, 2022) and in the Navy's rulemaking/LOA 
application (https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities) and are summarized here.

Dates and Duration

    Training activities will be conducted intermittently in the GOA 
Study Area over a maximum time period of up to 21 consecutive days 
annually from April to October to support a major joint training 
exercise in Alaska and off the Alaskan coast that involves the 
Departments of the Navy, Army, Air Force, and Coast Guard. The 
participants report to a unified or joint commander who coordinates the 
activities planned to demonstrate and evaluate the ability of the 
services to engage in a conflict and carry out plans in response to a 
threat to national security. The specified activities will occur over a 
maximum time period of up to 21 consecutive days each year during the 
7-year period of validity of the regulations. The planned number of 
training activities are described in the Detailed Description of 
Proposed Activities section (Table 3).

Geographical Region

    The GOA Study Area is entirely at sea and is comprised of the TMAA 
and a warning area in the Gulf of Alaska, and the WMA. The term ``at-
sea'' refers to training activities in the Study Area (both the TMAA 
and WMA) that occur (1) on the ocean surface, (2) beneath the ocean 
surface, and (3) in the air above the ocean surface. Navy training 
activities occurring on or over the land outside the GOA Study Area are 
not included in this rule, and are covered under separate environmental 
documentation prepared by the U.S. Air Force and the U.S. Army. As 
depicted in Figure 1 of the proposed rule (87 FR 49656; August 11, 
2022), the TMAA is a polygon roughly resembling a rectangle oriented 
from northwest to southeast, approximately 300 nmi (556 km) in length 
by 150 nmi (278 km) in width, located south of Montague Island and east 
of Kodiak Island. The GOA Study Area boundary was intentionally 
designed to avoid Endangered Species Act (ESA)-designated Steller sea 
lion critical habitat. The WMA is located south and west of the TMAA, 
and provides an additional 185,806 nmi\2\ (637,297 km\2\) of surface, 
sub-surface, and airspace to support training activities occurring 
within the TMAA. The boundary of the WMA follows the bottom of the 
slope at the 4,000 m contour line, and was configured to avoid overlap 
and impacts to ESA-designated critical habitat, biologically important 
areas (BIAs), migration routes, and primary fishing grounds. The WMA 
provides additional airspace and sea space for aircraft and vessels to 
maneuver during training activities for increased training complexity. 
The TMAA and WMA are temporary areas established within the GOA for 
ships, submarines, and aircraft to conduct training activities. 
Additional detail can be found in Chapter 2 of the Navy's rulemaking/
LOA application.

Primary Mission Areas

    The Navy categorizes many of its training activities into 
functional warfare areas called primary mission areas. The Navy's 
planned activities for the GOA Study Area generally fall into the 
following six primary mission areas: Air Warfare; Surface Warfare; 
Anti-Submarine Warfare; Electronic Warfare; Naval Special Warfare; and 
Strike Warfare. Most activities conducted in the GOA are categorized 
under one of these primary mission areas; activities that do not fall 
within one of these areas are listed as ``support operations'' or 
``other training activities.'' Each warfare community (aviation, 
surface, and subsurface) may train in some or all of these primary 
mission areas. A description of the sonar, munitions, targets, systems, 
and other materials used during training activities within these 
primary mission areas is provided in Appendix A (Navy Activities 
Descriptions) of the 2022 GOA FSEIS/OEIS.
    The Navy describes and analyzes the effects of its training 
activities within the 2022 GOA FSEIS/OEIS. In its assessment, the Navy 
concluded that of the activities to be conducted within the GOA Study 
Area, sonar use and in-air explosives occurring at or above the water 
surface were the stressors resulting in impacts on marine mammals that 
could rise to the level of harassment as defined under the MMPA. (The 
Navy is not proposing to conduct any activities that use in-water or 
underwater explosives.) These activities are limited to the TMAA. No 
activities involving sonar use or explosives would occur in the WMA or 
the portion of the warning area that extends beyond the TMAA. 
Therefore, the Navy's rulemaking/LOA application provides the Navy's 
assessment of potential effects from sonar use and explosives occurring 
at or above the water surface in terms of the various warfare mission 
areas they are associated with. Those mission areas include the 
following:
     Surface Warfare (in-air detonations at or above the water 
surface); \1\ and
---------------------------------------------------------------------------

    \1\ Defined herein as being within 10 meters of the ocean 
surface.
---------------------------------------------------------------------------

     Anti-Submarine warfare (sonar and other transducers).
    The Navy's activities in Air Warfare, Electronic Warfare, Naval 
Special Warfare, Strike Warfare, Support Operations, and Other Training 
Activities do not involve sonar and other transducers, detonations at 
or near the surface, or any other stressors that could result in 
harassment, serious injury, or mortality of marine mammals. Therefore, 
the activities in these warfare areas are not discussed further in this 
rule, but are analyzed fully in the 2022 GOA FSEIS/OEIS. Additional 
detail regarding the primary mission areas was provided in our Federal 
Register notice of proposed rulemaking (87 FR 49656; August 11, 2022); 
please see that notice of proposed rulemaking or the Navy's application 
for more information.

Overview of the Major Training Exercise Within the GOA Study Area

    The training activities in the GOA Study Area are considered to be 
a major training exercise (MTE). An MTE, for purposes of this 
rulemaking, is comprised of several unit-level activities conducted by 
several units operating together, commanded and controlled by a single 
Commander, and potentially generating more than 100 hours of active 
sonar. These exercises typically employ an exercise scenario developed 
to train and evaluate the exercise participants in tactical and 
operational

[[Page 607]]

tasks. In an MTE, most of the activities being directed and coordinated 
by the Commander in charge of the exercise are identical in nature to 
the activities conducted during individual, crew, and smaller unit-
level training events. In a MTE, however, these disparate training 
tasks are conducted in concert, rather than in isolation. At most, only 
one MTE will occur in the GOA Study Area per year (over a maximum of 21 
days).

Description of Stressors

    The Navy uses a variety of sensors, platforms, weapons, and other 
devices, including ones used to ensure the safety of Sailors and 
Marines, to meet its mission. Training with these systems may introduce 
sound and energy into the environment. The following subsections 
describe the acoustic and explosive stressors for marine mammals and 
their habitat (including prey species) within the GOA Study Area. 
Because of the complexity of analyzing sound propagation in the ocean 
environment, the Navy relied on acoustic models in its environmental 
analyses and rulemaking/LOA application that considered sound source 
characteristics and varying ocean conditions across the GOA Study Area. 
Stressor/resource interactions that were determined to have de minimis 
or no impacts (e.g., vessel noise, aircraft noise, weapons noise, and 
high-altitude (greater than 10 m above the water surface) explosions) 
were not carried forward for analysis in the Navy's rulemaking/LOA 
application. The Navy fully considered the possibility of vessel 
strike, conducted an analysis, and determined that requesting take of 
marine mammals by vessel strike was not warranted. Although the Navy 
did not request take for vessel strike, NMFS also fully analyzed the 
potential for vessel strike of marine mammals as part of this 
rulemaking. Therefore, this stressor is discussed in detail below. No 
Sinking Exercise (SINKEX) events are planned in the GOA Study Area for 
this rulemaking, nor is establishment and use of a Portable Undersea 
Tracking Range (PUTR) planned. NMFS reviewed the Navy's analysis and 
conclusions on de minimis and no-impact sources and finds them complete 
and supportable.
    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), incidental sources of broadband sound produced as a byproduct 
of vessel movement, aircraft transits, and use of weapons or other 
deployed objects. 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.
    In order to better organize and facilitate the analysis of 
approximately 300 sources of underwater sound used by the Navy, 
including sonar and other transducers and explosives, a series of 
source classifications, or source bins, were developed. The source 
classification bins do not include the broadband noise produced 
incidental to vessel movement, aircraft transits, and weapons firing. 
Noise produced from vessel movement, aircraft transits, and use of 
weapons or other deployed objects is not carried forward because those 
activities were found to have de minimis or no impacts, as described 
above.
    The use of source classification bins provides the following 
benefits:
     Provides the ability for new sensors or munitions to be 
covered under existing authorizations, as long as those sources fall 
within the parameters of a ``bin'';
     Improves efficiency of source utilization data collection 
and reporting requirements anticipated under the MMPA authorizations;
     Ensures a precautionary approach to all impact estimates, 
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;
     Allows analyses to be conducted in a more efficient 
manner, without any compromise of analytical results; and
     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 
Navy 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 rule, the terms sonar and 
other transducers will be used to indicate active sound sources unless 
otherwise specified.
    The Navy employs 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, 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.
    Additional detail regarding sound sources and platforms and 
categories of acoustic stressors was provided in our Federal Register 
notice of proposed rulemaking (87 FR 49656; August 11, 2022); please 
see that notice of proposed rulemaking or the Navy's application for 
more information.
    Sonars and other transducers are grouped into classes that share an 
attribute, such as frequency range or purpose of use. As detailed 
below, classes are further sorted by bins based on the frequency or 
bandwidth; source level; and, when warranted, the application in which 
the source would be used. Unless stated otherwise, a reference distance 
of 1 meter (m) is used for sonar and other transducers.
     Frequency of the non-impulsive acoustic source:
    [cir] Low-frequency sources operate below 1 kHz;
    [cir] Mid-frequency sources operate at and above 1 kHz, up to and 
including 10 kHz;
    [cir] High-frequency sources operate above 10 kHz, up to and 
including 100 kHz;
    [cir] Very-high-frequency sources operate above 100 kHz but below 
200 kHz;
     Sound pressure level of the non-impulsive source;
    [cir] Greater than 160 decibels (dB) re 1 micro Pascal ([micro]Pa), 
but less than 180 dB re: 1 [micro]Pa;
    [cir] Equal to 180 dB re: 1 [micro]Pa and up to 200 dB re: 1 
[micro]Pa;
    [cir] Greater than 200 dB re: 1 [micro]Pa;
     Application in which the source would be used:
    [cir] Sources with similar functions that have similar 
characteristics, such as pulse length (duration of each pulse), beam 
pattern, and duty cycle.

[[Page 608]]

    The bins used for classifying active sonars and transducers that 
are quantitatively analyzed for use in the TMAA are shown in Table 1 
below. While general parameters or source characteristics are shown in 
the table, the actual source parameters are classified. Acoustic source 
bins used in the planned activities will vary annually. The seven-year 
totals for the planned training activities take into account that 
annual variability.

                    Table 1--Sonar and Other Transducers Quantitatively Analyzed in the TMAA
----------------------------------------------------------------------------------------------------------------
                                         For annual training activities
-----------------------------------------------------------------------------------------------------------------
     Source class category           Bin          Description         Units           Annual       7-Year total
----------------------------------------------------------------------------------------------------------------
Mid-Frequency (MF) Tactical     MF1..........  Hull-mounted                   H              271           1,897
 and non-tactical sources that                  surface ship
 produce signals from 1 to 10                   sonars (e.g.,
 kHz.                                           AN/SQS-53C and
                                                AN/SQS-60).
                                MF3..........  Hull-mounted                   H               25             175
                                                submarine
                                                sonars (e.g.,
                                                AN/BQQ-10).
                                MF4..........  Helicopter-                    H               27             189
                                                deployed
                                                dipping sonars
                                                (e.g., AN/AQS-
                                                22).
                                MF5..........  Active acoustic                I              126             882
                                                sonobuoys.
                                               (e.g., DICASS)..
                                MF6..........  Active                         I               14              98
                                                underwater
                                                sound signal
                                                devices (e.g.,
                                                MK 84).
                                MF11.........  Hull-mounted                   H               42             294
                                                surface ship
                                                sonars with an
                                                active duty
                                                cycle greater
                                                than 80%.
                                MF12.........  Towed array                    H               14              98
                                                surface ship
                                                sonars with an
                                                active duty
                                                cycle greater
                                                than 80%.
High-Frequency (HF) Tactical    HF1..........  Hull-mounted                   H               12              84
 and non-tactical sources that                  submarine
 produce signals greater than                   sonars.
 10 kHz but less than 100 kHz.                 (e.g., AN/BQQ-
                                                10).
Anti-Submarine Warfare (ASW)    ASW1.........  MF systems                     H               14              98
 Tactical sources used during   ASW2.........   operating above               H               42             294
 ASW training activities.                       200 dB.
                                               MF Multistatic
                                                Active Coherent
                                                sonobuoy (e.g.,
                                                AN/SSQ-125).
                                ASW3.........  MF towed active                H              273           1,911
                                                acoustic
                                                countermeasure
                                                systems.
                                               (e.g., AN/SLQ-
                                                25).
                                ASW4.........  MF expendable                  I                7              49
                                                active acoustic
                                                device
                                                countermeasures
                                                (e.g., MK3).
----------------------------------------------------------------------------------------------------------------
Notes: H = hours, I = count (e.g., number of individual pings or individual sonobuoys), DICASS = Directional
  Command Activated Sonobuoy System.

Explosives
    This section describes the characteristics of explosions during 
naval training. The activities analyzed in the Navy's rulemaking/LOA 
application that use explosives are described in additional detail in 
Appendix A (Navy Activity Descriptions) of the 2022 GOA FSEIS/OEIS. 
Explanations of the terminology and metrics used when describing 
explosives in the Navy's rulemaking/LOA application are also in 
Appendix B (Acoustic and Explosive Concepts) of the 2022 GOA FSEIS/
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 in 
the warhead, the type of explosive material, the boundaries and 
characteristics of the propagation medium, the detonation depth, and 
the depth of the receiver (i.e., marine mammal). The net explosive 
weight, which is the explosive power of a charge expressed as the 
equivalent weight of trinitrotoluene (TNT), accounts for the first two 
parameters. The effects of these factors are explained in Appendix B 
(Acoustic and Explosive Concepts) of the 2022 GOA FSEIS/OEIS. The 
activities analyzed in the Navy's rulemaking/LOA application and this 
final rule that use explosives are described in further detail in 
Appendix A (Navy Activities Descriptions) of the 2022 GOA FSEIS/OEIS. 
Explanations of the terminology and metrics used when describing 
explosives are provided in Appendix B (Acoustic and Explosive Concepts) 
of the 2022 GOA FSEIS/OEIS.
    Explosive detonations during training activities are from the use 
of explosive bombs and naval gun shells; however, no in-water explosive 
detonations are included as part of the training activities. For 
purposes of the analysis in this rule, detonations occurring in air at 
a height of 33 ft (10 m) or less above the water surface, and 
detonations occurring directly on the water surface, were modeled to 
detonate at a depth of 0.3 ft (0.1 m) below the water surface since 
there is currently no other identified methodology for modeling 
potential effects to marine mammals that are underwater as a result of 
detonations occurring in-air at or above the surface of the ocean 
(within 10 m above the surface). This conservative approach over-
estimates the potential underwater impacts due to low-altitude and 
surface explosives by assuming that all explosive energy is released 
and remains under the water surface.
    Explosive stressors resulting from the detonation of some 
munitions, such as missiles and gun rounds used in air-air and surface-
air scenarios, occur at high altitude. The resulting sound energy from 
those detonations in air would not impact marine mammals. The explosive 
energy released by detonations in air has been well studied, and basic 
methods are available to estimate the explosive energy exposure with 
distance from the detonation (e.g., U.S. Department of the Navy 
(1975)). In air, the propagation of impulsive noise from an explosion 
is highly influenced by atmospheric conditions, including temperature 
and wind. While basic estimation methods do not consider the unique 
environmental conditions that may be present on a given day, they do 
allow for approximation of explosive energy propagation under neutral 
atmospheric conditions. Explosions that occur during Air Warfare will 
typically be at a sufficient altitude that a large portion of the sound 
will refract upward due to cooling temperatures with increased 
altitude. Based on an understanding of the explosive energy released by 
detonations in air, detonations occurring in air at altitudes greater 
than 10 m above the surface of the ocean are not likely to result in 
acoustic impacts on marine mammals; therefore, these types of explosive 
activities will not be discussed further

[[Page 609]]

in this document. (Note that most of these in-air detonations would 
occur at altitudes substantially greater than 10 m above the surface of 
the ocean, as described in further detail in section 3.0.4.2.2 
(Explosions in Air) of the 2022 GOA FSEIS/OEIS.) Activities such as 
air-surface bombing or surface-surface gunnery scenarios may involve 
the use of explosive munitions that detonate upon impact with targets 
at or above the water surface (within 10 m above the surface). For 
these activities, acoustic effects modeling was undertaken as described 
below.
    In order to organize and facilitate the analysis of explosives, 
explosive classification bins were developed. The use of explosive 
classification bins provides the same benefits as described for 
acoustic source classification bins discussed above and in Section 
1.4.1 (Acoustic Stressors) of the Navy's rulemaking/LOA application.
    The explosive bin types and the number of explosives detonating at 
or above the water surface in the TMAA are shown in Table 2.

   Table 2--Explosive Sources Quantitatively Analyzed That Detonate at or Above the Water Surface in the TMAA
----------------------------------------------------------------------------------------------------------------
                                                                                            Number of explosives
                                                                     Number of explosives    with the specified
 Explosives (source class and net explosive weight (NEW)) (lb.) *     with the specified      activity (7-year
                                                                     activity (annually)           total)
----------------------------------------------------------------------------------------------------------------
E5 (>5-10 lb. NEW)................................................                     56                    392
E9 (>100-250 lb. NEW).............................................                     64                    448
E10 (>250-500 lb. NEW)............................................                      6                     42
E12 (>650-1,000 lb. NEW)..........................................                      2                     14
----------------------------------------------------------------------------------------------------------------
* All of the E5, E9, E10, and E12 explosives would occur in-air, at or above the surface of the water, and would
  also occur offshore away from the continental shelf and slope beyond the 4,000-meter isobath.

    Propagation of explosive pressure waves in water is highly 
dependent on environmental characteristics such as bathymetry, bottom 
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 B (Acoustic and Explosive Concepts) of the 2022 GOA FSEIS/OEIS 
explains the characteristics of explosive detonations and how the above 
factors affect the propagation of explosive energy in the water.
    For in-air explosives detonating at or above the water surface, the 
model estimating acoustic impacts assumes that all acoustic energy from 
the detonation is underwater with no loss of sound or energy into the 
air. Important considerations must be factored into the analysis of 
results with these modeling assumptions, given that the peak pressure 
and sound from a detonation in air significantly decreases across the 
air-water interface as it is partially reflected by the water's surface 
and partially transmitted underwater, as detailed in the following 
paragraphs.
    Detonation of an explosive in air creates a supersonic high-
pressure shock wave that expands outward from the point of detonation 
(Kinney and Graham, 1985; Swisdak, 1975). The near-instantaneous rise 
from ambient to an extremely high peak pressure is what makes the 
explosive shock wave potentially injurious to an animal experiencing 
the rapid pressure change (U.S. Department of the Navy, 2017a). As the 
shock wave-front travels away from the point of detonation, it slows 
and begins to behave as an acoustic wave-front traveling at the speed 
of sound. Whereas a shock wave from a detonation in-air has an abrupt 
peak pressure, that same pressure disturbance when transmitted through 
the water surface results in an underwater pressure wave that begins 
and ends more gradually compared with the in-air shock wave, and 
diminishes with increasing depth and distance from the source (Bolghasi 
et al., 2017; Chapman and Godin, 2004; Cheng and Edwards, 2003; Moody, 
2006; Richardson et al., 1995; Sawyers, 1968; Sohn et al., 2000; 
Swisdak, 1975; Waters and Glass, 1970; Woods et al., 2015). The 
propagation of the shock wave in-air and then transitioning underwater 
is very different from a detonation occurring deep underwater where 
there is little interaction with the surface. In the case of an 
underwater detonation occurring just below the surface, a portion of 
the energy from the detonation would be released into the air (referred 
to as surface blow off), and at greater depths a pulsating, air-filled 
cavitation bubble would form, collapse, and reform around the 
detonation point (Urick, 1983). The Navy's acoustic effects model for 
analyzing underwater impacts on marine species does not account for the 
loss of energy due to surface blow-off or cavitation at depth. Both of 
these phenomena would diminish the magnitude of the acoustic energy 
received by an animal under real-world conditions (U.S. Department of 
the Navy, 2018b).
    To more completely analyze the results predicted by the Navy's 
acoustic effects model from detonations occurring in-air above the 
ocean surface, it is necessary to consider the transfer of energy 
across the air-water interface. Much of the scientific literature on 
the transferal of shock wave impulse across the air-water interface has 
focused on energy from sonic booms created by fast moving aircraft 
flying at low altitudes above the ocean (Chapman and Godin, 2004; Cheng 
and Edwards, 2003; Moody, 2006; Sawyers, 1968; Waters and Glass, 1970). 
The shock wave created by a sonic boom is similar to the propagation of 
a pressure wave generated by an explosion (although having a 
significantly slower rise in peak pressure) and investigations of sonic 
booms are somewhat informative. Waters and Glass (1970) were also 
investigating sonic booms, but their methodology involved actual in-air 
detonations. In those experiments, they detonated blasting caps 
elevated 30 ft (9 m) above the surface in a flooded quarry and measured 
the resulting pressure at and below the surface to determine the 
penetration of the shock wave across the air-water interface. 
Microphones above the water surface recorded the peak pressure in-air, 
and hydrophones at various shallow depths underwater recorded the 
unreflected remainder of the pressure wave after transition across the 
air-water interface. The peak pressure measurements were compared and 
the results supported the theoretical expectations for the penetration 
of a pressure wave from air into water,

[[Page 610]]

including the predicted exponential decay of energy with distance from 
the source underwater. In effect, the air-water interface acted as a 
low-pass filter eliminating the high-frequency components of the shock 
wave. At incident angles greater than 14 degrees perpendicular to the 
surface, most of the shock wave from the detonation was reflected off 
the water surface, which is consistent with results from similar 
research (Cheng and Edwards, 2003; Moody, 2006; Yagla and Stiegler, 
2003). Given that marine mammals spend, on average, up to 90 percent of 
their time underwater (Costa, 1993; Costa and Block, 2009), and the 
shock wave from a detonation is only a few milliseconds in duration, 
marine mammals are unlikely to be exposed in-air when surfaced.

Vessel Strike

    NMFS also considered the chance that a vessel utilized in training 
activities could strike a marine mammal in the GOA Study Area, 
including both the TMAA and WMA portions of the Study Area. Vessel 
strikes have the potential to result in incidental take from serious 
injury and/or mortality. Vessel strikes are not specific to any 
particular training activity, but rather are a limited, sporadic, and 
incidental result of Navy vessel movement within a study area. NMFS' 
detailed analysis of the likelihood of vessel strike was provided in 
the ``Potential Effects of Vessel Strike'' section of our proposed 
rulemaking (87 FR 49656; August 11, 2022); please see that notice of 
proposed rulemaking or the Navy's application for more information. No 
additional information has been received since publication of the 
proposed rule that substantively changes the agency's analysis or 
conclusions. Therefore, the information and analysis included in the 
proposed rule supports NMFS' concurrence with the Navy's conclusion and 
our final determination that vessel strikes of marine mammals, and 
associated serious injury or mortality, are not likely to result from 
the Navy's activities included in this seven-year rule, and vessel 
strikes are not discussed further.

Detailed Description of Specified Activities

Planned Training Activities

    The Navy's Operational Commands have identified activity levels 
that are needed in the GOA Study Area to ensure naval forces have 
sufficient training, maintenance, and new technology to meet Navy 
missions in the Gulf of Alaska. Training prepares Navy personnel to be 
proficient in safely operating and maintaining equipment, weapons, and 
systems to conduct assigned missions.
    The Navy plans to conduct a single carrier strike group (CSG) 
exercise, which will last for a maximum of 21 consecutive days in a 
year. The CSG exercise is comprised of several individual training 
activities. Table 3 lists and describes those individual activities 
that may result in takes of marine mammals. The events listed will 
occur intermittently during the 21 days and could be simultaneous and 
in the same general area within the TMAA or could be independent and 
spatially separate from other ongoing activities. The table is 
organized according to primary mission areas and includes the activity 
name, associated stressor(s), description and duration of the activity, 
sound source bin, the areas where the activities are conducted in the 
GOA Study Area, the maximum number of events per year in the 21-day 
period, and the maximum number of events over 7 years. For further 
information regarding the primary platform used (e.g., ship or aircraft 
type) see Appendix A (Navy Activities Descriptions) of the 2022 GOA 
FSEIS/OEIS.
    Not all sound sources are used with each activity. The ``Annual # 
of Events'' column indicates the maximum number of times that activity 
could occur during any single year. The ``7-Year # of Events'' is the 
maximum number of times an activity would occur over the 7-year period 
of the regulations if the training occurred each year and at the 
maximum levels requested. The events listed will occur intermittently 
during the exercise over a maximum of 21 days. The maximum number of 
activities may not occur in some years, and historically, training has 
occurred only every other year. However, to conduct a conservative 
analysis, NMFS analyzed the maximum times these activities could occur 
over one year and 7 years. (Note the Navy proposes no low-frequency 
active sonar (LFAS) use for the activities in this rulemaking.)

                Table 3--Training Activities Analyzed for the 7-Year Period in the GOA Study Area
----------------------------------------------------------------------------------------------------------------
   Stressor                                                                         Annual # of     7-Year # of
   category          Activity         Description             Source bin              events          events
----------------------------------------------------------------------------------------------------------------
                                                 Surface Warfare
----------------------------------------------------------------------------------------------------------------
Explosive.....  Gunnery Exercise,  Surface ship       E5........................               6              42
                 Surface-to-        crews fire inert
                 Surface.           small-caliber,
                (GUNEX-S-S)......   inert medium-
                                    caliber, or
                                    large-caliber
                                    explosive rounds
                                    at surface
                                    targets.
Explosive.....  Bombing Exercise.  Fixed-wing         E9, E10, E12..............              18             126
                (Air-to-Surface).   aircraft conduct
                (BOMBEX [A-S])...   bombing
                                    exercises
                                    against
                                    stationary
                                    floating
                                    targets, towed
                                    targets, or
                                    maneuvering
                                    targets.
----------------------------------------------------------------------------------------------------------------
                                          Anti-Submarine Warfare (ASW)
----------------------------------------------------------------------------------------------------------------
Acoustic......  Tracking           Helicopter crews   MF4, MF5, MF6.............              22             154
                 Exercise--Helico   search for,
                 pter.              track, and
                (TRACKEX--Helo)..   detect
                                    submarines.
Acoustic......  Tracking           Maritime patrol    MF5, MF6, ASW2............              13              91
                 Exercise--Mariti   aircraft crews
                 me Patrol          search for,
                 Aircraft.          track, and
                (TRACKEX--MPA)...   detect
                                    submarines.
Acoustic......  Tracking           Surface ship       ASW1, ASW3, MF1, MF11,                   2              14
                 Exercise--Ship.    crews search       MF12.
                (TRACKEX--Ship)..   for, track, and
                                    detect
                                    submarines.
Acoustic......  Tracking           Submarine crews    ASW4, HF1, MF3............               2              14
                 Exercise--Submar   search for,
                 ine.               track, and
                (TRACKEX--Sub)...   detect
                                    submarines.
----------------------------------------------------------------------------------------------------------------
Notes: S-S = Surface to Surface, A-S = Air to Surface.

Standard Operating Procedures

    For training to be effective, personnel must be able to safely use 
their sensors and weapon systems as they are intended to be used in 
military missions and combat operations and to their optimum 
capabilities. Standard operating procedures applicable to training have 
been developed through

[[Page 611]]

years of experience, and their primary purpose is to provide for safety 
(including public health and safety) and mission success. In many 
cases, there are benefits to natural and cultural resources resulting 
from standard operating procedures.
    Because standard operating procedures are essential to safety and 
mission success, the Navy considers them to be part of the planned 
specified activities, and has included them in the environmental 
analysis in the 2022 GOA FSEIS/OEIS. Additional details on standard 
operating procedures were provided in our Federal Register notice of 
proposed rulemaking (87 FR 49656; August 11, 2022); please see that 
notice of proposed rulemaking or the Navy's application for more 
information.

Comments and Responses

    We published the proposed rule in the Federal Register on August 
11, 2022 (87 FR 49656), with a 45-day comment period. With that 
proposed rule, we requested public input on our analyses, our 
preliminary findings, and the proposed regulations, and requested that 
interested persons submit relevant information and comments. During the 
45-day comment period, we received four comments. Of this total, one 
submission was from the Marine Mammal Commission (Commission), and the 
remaining comments were from a non-governmental organization (NGO) and 
private citizens. Additionally, 2 days after the public comment period 
ended, we received a comment letter from the Center for Biological 
Diversity (CBD).
    NMFS has reviewed and considered all public comments received on 
the proposed rule and issuance of the LOA, including comments received 
from CBD after the public comment period ended. All substantive 
comments and our responses are described below. We organize our comment 
responses by major categories.

Impact Analysis and Thresholds

    Comment 1: The Commission strongly recommended that NMFS refrain 
from using cutoff distances in conjunction with the Bayesian behavioral 
response functions (BRFs) and re-estimate the numbers of marine mammal 
takes based solely on the Bayesian BRFs in the final rule, as the use 
of cutoff distances could be perceived as an attempt to reduce the 
numbers of takes (85 FR 72326; November 12, 2020). The Commission 
stated that as such, providing better-substantiated, alternative cut-
off distances is unnecessary, as their use in conjunction with the 
Bayesian BRFs is redundant and potentially contradictory.
    Response: The consideration of proximity (cut-off distances) was 
part of the criteria developed in consultation between the Navy and 
NMFS, and is appropriate based on the best available science, which 
shows that marine mammal responses to sound vary based on both sound 
level and distance. Therefore, these cut-off distances were applied 
within the Navy's acoustic effects model. The derivation of the BRFs 
and associated cut-off distances is provided in the 2017 technical 
report titled ``Criteria and Thresholds for U.S. Navy Acoustic and 
Explosive Effects Analysis (Phase III).'' To account for non-applicable 
contextual factors, all available data on marine mammal reactions to 
actual Navy activities and other sound sources (or other large-scale 
activities such as seismic surveys when information on proximity to 
sonar sources was not available for a given species group) were 
reviewed to find the farthest distance to which significant behavioral 
reactions were observed. In applying the distance cut-offs in 
conjunction with the BRFs, these distances were rounded up to the 
nearest 5 or 10 km interval, and for moderate to large scale activities 
using multiple or louder sonar sources, these distances were greatly 
increased--doubled in most cases. The Navy's BRFs applied within these 
distances provide technically sound methods reflective of the best 
available science to estimate the impact and potential take for the 
actions analyzed within the 2022 GOA FSEIS/OEIS and included in this 
rule. NMFS has independently assessed the thresholds used by the Navy 
to identify Level B harassment by behavioral disturbance (referred to 
as ``behavioral harassment thresholds'' throughout the rest of the 
rule) and finds that they appropriately apply the best available 
science and it is not necessary to recalculate take estimates.
    Comment 2: The Commission recommended that NMFS explain why the 
constants and exponents for onset mortality and onset slight lung 
injury thresholds for the current phase of incidental take rulemaking 
for the Navy (Phase III) that consider lung compression with depth 
result in lower rather than higher absolute thresholds when animals 
occur at depths greater than 8 m in the preamble to the final rule.
    Response: The derivation of the explosive injury equations, 
including any assumptions, is provided in the 2017 technical report 
titled ``Criteria and Thresholds for U.S. Navy Acoustic and Explosive 
Effects Analysis (Phase III).'' The equations were modified for the 
current rulemaking period (Phase III) to fully incorporate the injury 
model in Goertner (1982), specifically to include lung compression with 
depth. NMFS independently reviewed and concurred with this approach.
    The impulse mortality/injury equations are depth dependent, with 
thresholds increasing with depth due to increasing hydrostatic pressure 
in the model for both the previous 2015-2020 phase of rulemaking (Phase 
II) and Phase III. The underlying experimental data used in Phase II 
and Phase III remain the same, and two aspects of the Phase III 
revisions explain the relationships the commenter notes:
    (1) The numeric coefficients in the equations are computed by 
inserting the Richmond et al. (1973) experimental data into the model 
equations. Because the Phase III model equation accounts for lung 
compression, the plugging of experimental exposure values into a 
different model results in different coefficients. The numeric 
coefficients are slightly larger in Phase III versus Phase II, 
resulting in a slightly greater threshold near the surface.
    (2) The rate of increase for the Phase II thresholds with depth is 
greater than the rate of increase for Phase III thresholds with depth 
because the Phase III equations take into account the corresponding 
reduction in lung size with depth (making an animal more vulnerable to 
injury per the Goertner model), as the commenter notes.
    Comment 3: The Commission recommended that NMFS use onset 
mortality, onset slight lung injury, and onset gastrointestinal (GI) 
tract injury thresholds rather than the 50-percent thresholds to 
estimate both the numbers of marine mammal takes and the respective 
ranges to effect for explosives for the final rule. The Commission 
stated that the current approach is inconsistent with the manner in 
which the Navy estimated the numbers of takes for Permanent Threshold 
Shift (PTS), Temporary Threshold Shift (TTS), and behavior for 
explosive activities, as all of those takes have been and continue to 
be based on onset, not 50 percent values.
    The Commission stated that in addition, the circumstances of the 
deaths of multiple common dolphins during one of the Navy's underwater 
detonation events in March 2011 (Danil and St. Leger, 2011) indicate 
that the Navy's mitigation measures are not fully effective, especially 
for explosive activities. Recently, Oedekoven and Thomas (2022) also 
confirmed the ineffectiveness of Navy lookouts to sight marine mammals 
at various distances

[[Page 612]]

during mid-frequency active (MFA) sonar exercises.
    If the Navy does not implement the Commission's recommendation, the 
Commission further recommended that NMFS (1) specify why it bases 
explosive thresholds for Level A harassment on onset PTS and Level B 
harassment on onset TTS and onset behavioral response, while the 
explosive thresholds for mortality and Level A harassment are based on 
the 50-percent criteria for mortality, slight lung injury, and GI tract 
injury, (2) provide scientific justification supporting the assumption 
that slight lung and GI tract injuries are less severe than PTS and 
thus the 50-percent rather than onset criteria are more appropriate for 
estimating Level A harassment for those types of injuries, and (3) 
justify why the number of estimated mortalities should be predicated on 
at least 50 percent rather than 1 percent of the animals dying, 
particularly given the ineffectiveness of lookouts.
    Response: For explosives, the type of data available are different 
from those available for hearing impairment, and this difference 
supports the use of different prediction methods. Nonetheless, as 
appropriate, and similar to take estimation methods for PTS, NMFS and 
the Navy have used a combination of exposure thresholds and 
consideration of mitigation to inform the take estimates. The Navy used 
the range to 1 percent risk of onset mortality and onset injury (also 
referred to as ``onset'' in the 2022 GOA FSEIS/OEIS) to inform the 
development of mitigation zones for explosives. Ranges to effect based 
on 1 percent risk criteria to onset injury and onset mortality were 
examined to ensure that explosive mitigation zones would encompass the 
range to any potential mortality or non-auditory injury, affording 
actual protection against these effects. In all cases, the mitigation 
zones for explosives extend beyond the range to 1 percent risk of onset 
non-auditory injury, even for a small animal (representative mass = 5 
kg). Given the implementation and expected effectiveness of this 
mitigation, the application of the 50 percent threshold is appropriate 
for the purposes of estimating take in consideration of the required 
mitigation. Using the 1 percent onset non-auditory injury risk criteria 
to estimate take would result in an over-estimate of take, and would 
not afford extra protection to any animal. Specifically, calculating 
take based on marine mammal density within the area where an animal 
might be exposed above the 1 percent risk to onset injury and onset 
mortality criteria would over-predict effects because a subset of those 
exposures will not happen because of the reduction provided by the 
mitigation. The Navy, in coordination with NMFS, has determined that 
the 50 percent incidence of onset injury and onset mortality occurrence 
is a reasonable representation of a potential effect and appropriate 
for take estimation, given the mitigation requirements at the 1 percent 
onset injury and onset mortality threshold, and the area ensonified 
above this threshold would capture the appropriate reduced number of 
likely injuries.
    While the approaches for evaluating non-auditory injury and 
mortality are based on different types of data and analyses from the 
evaluation of PTS and behavioral disturbance, and are not identical, 
NMFS disagrees with the commenter's assertion that the approaches are 
inconsistent, as both approaches consider a combination of thresholds 
and mitigation (where applicable) to inform take estimates. For the 
same reasons, it is not necessary for NMFS to ``provide scientific 
justification supporting the assumption that slight lung and GI tract 
injuries are less severe than PTS,'' as that assumption is not part of 
NMFS' rationale for the methods used. NMFS has explained in detail its 
justification for the number of estimated mortalities, which is based 
on both the 50 percent threshold and the mitigation applied at the one 
percent threshold. Further, we note that many years of Navy monitoring 
following explosive exercises has not detected evidence that any injury 
or mortality has resulted from Navy explosive exercises with the 
exception of one incident with dolphins in California, after which 
mitigation was adjusted to better account for explosives with delayed 
detonations (i.e., zones for events with time-delayed firing were 
enlarged).
    Furthermore, for these reasons, the methods used for estimating 
mortality and non-auditory injury are appropriate for estimating take, 
including determining the ``significant potential'' for non-auditory 
injury consistent with the statutory definition of Level A harassment 
for military readiness activities, within the limits of the best 
available science. Using the one percent threshold would be 
inappropriate and result in an overestimation of effects, whereas given 
the mitigation applied within this larger area, the 50 percent 
threshold results in an appropriate mechanism for estimating the 
significant potential for non-auditory injury.
    While the Lookout Effectiveness Study suggests that detection of 
marine mammals is less certain than previously assumed, given the 
modeling results, this does not affect whether use of the 50 percent 
threshold is appropriate for calculating mortality from explosives. For 
explosives in bin E12, the bin with the largest net explosive weight 
(NEW; >650-1,000 lb.) planned for use by the Navy in the GOA Study 
Area, the average range to 50 percent non-auditory injury for all 
marine mammal hearing groups (Table 30) is 190 m. The range to 50 
percent mortality risk for all marine mammal hearing groups (Table 31) 
for the same bin (E12) and the smallest (i.e., the most susceptible to 
mortality) modeled animal size (10 kg), is 55 m. The range to one 
percent onset mortality for the same bin (E12) and the smallest modeled 
animal size (10 kg) is 73 m (with a minimum and maximum of 65 m and 80 
m, respectively). Considering that zero takes by non-auditory injury 
were modeled without consideration of the planned mitigation measures, 
and with a zone almost 3.5 times larger than the 50 percent onset 
mortality zone for the highest NEW and most susceptible animal weight, 
mortality as a result of explosives is unlikely to occur, especially at 
larger distances than that which were modeled, regardless of lookout 
effectiveness. However, it is also important to note that the ranges to 
50 percent and one percent onset mortality for E12 explosives are both 
significantly smaller than the mitigation zones reported on in the 
Lookout Effectiveness Study (200, 500 and 1,000 yards; Oedekoven and 
Thomas, 2022).
    Comment 4: The Commission continues to maintain that NMFS has not 
provided adequate justification for dismissing the possibility that 
single underwater detonations can cause a behavioral response, and, 
therefore, again recommended that it estimate and authorize behavior 
takes of marine mammals during all explosive activities, including 
those that involve single detonations consistent with in-air explosive 
events.
    Response: NMFS acknowledges the possibility that single underwater 
detonations can cause a behavioral response. The current take estimate 
framework allows for the consideration of animals exhibiting behavioral 
disturbance during single explosions as they are counted as ``taken by 
Level B harassment'' if they are exposed above the TTS threshold, which 
is 5 decibels (dB) higher than the behavioral harassment threshold. We 
acknowledge in our analysis that individuals exposed above the TTS 
threshold may also be harassed by behavioral disruption and those 
potential impacts are considered

[[Page 613]]

in the negligible impact determination. Neither NMFS nor the Navy are 
aware of evidence to support the assertion that animals will have 
significant behavioral responses (i.e., those that would rise to the 
level of a take) to temporally and spatially isolated explosions at 
received levels below the TTS threshold. However, if any such responses 
were to occur, they would be expected to be few and to result from 
exposure to the somewhat higher received levels bounded by the TTS 
thresholds and would thereby be accounted for in the take estimates. 
The derivation of the explosive injury criteria is provided in the 2017 
technical report titled ``Criteria and Thresholds for U.S. Navy 
Acoustic and Explosive Effects Analysis (Phase III).''
    Regarding the assertion in the Commission's letter that the 
approaches for assessing the impacts from a single underwater 
detonation and a single in-air detonation are inconsistent, we 
disagree. Both approaches/thresholds are based on the best available 
data. As noted above, we are unaware of data suggesting that marine 
mammals will respond to single underwater explosive detonation below 
the TTS threshold in a manner that would qualify as a take. Conversely, 
for single in-air events such as missile launch noise and sonic booms, 
there are extensive data supporting the application of the lower 
behavioral thresholds, i.e., pinnipeds moving significant distances or 
flushing in response to these in-air levels of sounds.
    Comment 5: A commenter stated that the Navy must consider the risks 
of vessel noise on the species. Chronic stress in North Atlantic right 
whales is associated with exposure to low frequency noise from ship 
traffic. Specifically, ``the adverse consequences of chronic stress 
often include long-term reductions in fertility and decreases in 
reproductive behavior; increased rates of miscarriages; increased 
vulnerability to diseases and parasites; muscle wasting; disruptions in 
carbohydrate metabolism; circulatory diseases; and permanent cognitive 
impairment'' (Rolland et al., 2012). These findings have led 
researchers to conclude that ``over the long term, chronic stress 
itself can reduce reproduction, negatively affect health, and even kill 
outright'' (Rolland et al., 2007). North Pacific right whales likely 
suffer in the same ways.
    Response: NMFS did consider the risks of vessel noise on marine 
mammals. Navy vessels are designed to be quieter than civilian vessels, 
and the vessel noise associated with Navy activities is not expected to 
cause harassment of marine mammals (see the Potential Effects of 
Specified Activities on Marine Mammals and Their Habitat section in the 
proposed rule; 87 FR 49656; August 11, 2022). NMFS included an in-depth 
discussion of stress response in the Physiological Stress section of 
the proposed rule (87 FR 49656; August 11, 2022). There are currently 
neither adequate data nor mechanisms by which the impacts of stress 
from acoustic exposure can be reliably and independently quantified. 
However, stress effects that result from noise exposure likely often 
occur concurrently with behavioral harassment and many are likely 
captured and considered in the quantification of other takes by 
harassment that occur when individuals come within a certain distance 
of a sound source (behavioral harassment, PTS, and TTS).

Density Estimates

    Comment 6: The Commission recommended that NMFS (1) clarify how and 
for which species uncertainty was incorporated in the density estimates 
and whether and how uncertainty was incorporated in the group size 
estimates and specify the distribution(s) used and, (2) if uncertainty 
was not incorporated, re-estimate the numbers of marine mammal takes in 
the final rule based on the uncertainty inherent in the density 
estimates provided in Department of the Navy (2021) or the abundance 
estimates in the underlying references (NMFS stock assessment reports 
(SARs), Fritz et al. 2016, etc.) and the group size estimates provided 
in Department of the Navy (2020a). Furthermore, if uncertainty is not 
incorporated in the group size estimates, the Commission recommends 
that NMFS specify why it did not do so.
    Response: Similar to other Navy Phase III training and testing 
impact analyses, uncertainty was incorporated in species density and 
group size estimates for those species with uncertainty values 
available, when distributing the animats in the Navy Acoustic Effects 
Model. Since 2016, the Navy Acoustics Effects Model has been refined; 
marine species density estimates have been updated; and NMFS has 
published new effects criteria, weighting functions, and thresholds for 
multiple species, that are incorporated into the model analysis. As 
discussed in the technical report titled ``Quantifying Acoustic Impacts 
on Marine Mammals and Sea Turtles: Methods and Analytical Approach for 
Phase III Training and Testing'' (U.S. Department of the Navy, 2018), 
available at www.goaeis.com, marine mammal density data are provided as 
a 10x10 km grid where each cell has a mean density and standard error. 
In the Navy Acoustic Effects Model, species densities are distributed 
into simulation areas. Sixty distributions that vary based on the 
standard deviation of the density estimates are run per season for each 
species to account for statistical uncertainty in the density 
estimates.
    Clarification on the incorporation of uncertainty in density 
estimates is provided in the Density Technical Report ``U.S. Navy 
Marine Species Density Database Phase III for the Gulf of Alaska 
Temporary Maritime Activities Area,'' as cited in the 2022 GOA FSEIS/
OEIS and available at www.goaeis.com. Uncertainty in the density 
estimates was incorporated into the estimation of take for all species 
with appropriate measures of uncertainty available, which is most 
species.
    Using a mean density estimate that incorporates appropriate 
measures of uncertainty, as was done for the species listed in the 
Commission's comment, is a commonly used and scientifically valid 
method of estimating a value (i.e., a density in this context). There 
is equal probability of underestimating and overestimating takes even 
with a large coefficient of variation (CV) associated with a mean 
density estimate. Therefore, using the mean density and incorporating 
the CV into the distribution of animats in the Navy Acoustic Effects 
Model is reasonable and representative of species distribution in the 
GOA Study Area.
    Regarding pinnipeds, NMFS and the Navy continue to seek appropriate 
methods for incorporating uncertainty into density estimates for 
pinnipeds, and by extension, into the Navy's estimates of exposures. As 
the Commission noted in its comment, of the six pinniped species for 
which the Navy calculates densities, only the northern fur seal 
incorporated a CV as a measure of uncertainty in the density estimate. 
The CV was provided in the SAR (Muto et al., 2020a) as a measure of 
uncertainty in the abundance of northern fur seals, and that abundance 
(620,660 northern fur seals) was the basis for the density calculation, 
making the CV directly applicable to the density estimate. Only limited 
data were available for calculating densities for California sea lions 
and ribbon seals in the GOA Study Area, as described in the Density 
Technical Report, and no estimate of uncertainty in either the 
abundance or the density was available or could be estimated. The SAR 
did not provide a CV or other measure of uncertainty in the abundance 
estimate

[[Page 614]]

for northern elephant seals, so none was available for use in the 
density calculation. The SAR provided a standard error in the abundance 
estimates for the four harbor seal stocks (Muto et al., 2020a) as a 
measure of uncertainty in the abundance; however, those abundance 
estimates were combined as described in the Density Technical Report 
and used to calculate an abundance over the continental shelf--the only 
part of the harbor seal distribution within the GOA Study Area. The 
stock abundances were not direct inputs into the density calculations; 
therefore, it would not have been statistically correct to manipulate 
(e.g., sum or average) four standard error values representing 
uncertainty in the separate abundance estimates to derive a standard 
error and apply it to a calculated continental shelf abundance. The 
abundance for Steller sea lions was taken from Fritz et al. (2016) 
Table 1A (pups) and Table 6 (non-pups for Eastern Gulf). The 
recommended formula of pup count x 3.5 was used to estimate the Central 
Gulf non-pup abundance. (Note that Table 6 only included the abundance 
for Rookery Cluster Area-9, a portion of the Central Gulf abundance.) 
No measure of uncertainty in the abundance is provided in either table 
(Fritz et al., 2016). The Navy intends to incorporate, and NMFS intends 
to consider, uncertainty in its density estimates for pinnipeds in the 
future, as data or statistically valid methodologies allow.
    NMFS concurs with the Navy's use of uncertainty, where available, 
in the densities applied through their model and reiterates that the 
best available science was used and applied appropriately to estimate 
marine mammal take.
    Comment 7: The Commission stated that in its January 4, 2021 letter 
on the 2020 GOA Draft Supplemental Environmental Impact Statement 
(DSEIS)/OEIS, it recommended that the Navy request a small number of 
gray whale takes in its rulemaking/LOA application regardless of 
whether its model estimated zero takes. Density estimates are not 
available for gray whales in the TMAA, but the whales could occur there 
within the timeframe that the Navy's activities would occur (Department 
of the Navy, 2020b and 2021; Ferguson et al., 2015; Palacios et al., 
2021). The Navy did not request any gray whale takes in its revised LOA 
application, but NMFS proposed to authorize four Level B harassment 
behavioral takes of the Eastern North Pacific (ENP) stock in the 
proposed rule (87 FR 49656; August 11, 2022) based on group size from 
Rone et al. (2017). The Commission supports that approach but is unsure 
why NMFS did not also propose to authorize takes of the Western North 
Pacific (WNP) stock of gray whales. Palacios et al. (2021) and Mate et 
al. (2015) have shown that gray whales tagged off eastern Russia have 
been tracked through the TMAA, similar to and in about equal proportion 
to ENP gray whales. Telemetry, photo-identification, and genetic 
studies have all shown movements and interchange between the WNP and 
ENP stocks of gray whales (Weller et al., 2012, Urb[aacute]n et al., 
2019, Lang et al., 2022). Therefore, the Commission recommends that 
NMFS include in the final rule four Level B harassment behavioral takes 
for the ENP and WNP stocks of gray whales, as well as its proposed 
Level B harassment behavioral takes for the WNP stock of humpback 
whales.
    Response: This final rule authorizes take of four Eastern North 
Pacific stock gray whales, as proposed. However, it does not authorize 
four takes of Western North Pacific gray whales as recommended by the 
Commission. As noted by the Commission, Palacios et al. (2021) and Mate 
et al. (2015) show that several gray whales tagged off of eastern 
Russia entered or came close to the TMAA. However, these occurrences 
were outside of the time period that the Navy plans to conduct its 
activity (April to October). Of the whales discussed in Palacios et al. 
(2021), one whale occurred in the TMAA on December 30 and 31, 2011, one 
whale occurred in the TMAA on March 29 and April 1, 2012, and later 
passed the TMAA approximately 600-700 km south of its boundary from 
December 26-31, 2011, and a third whale passed the TMAA approximately 
300-400 km south of its boundary from January 22-25, 2011. Of the 
whales tagged by Mate et al. (2015), three whales occurred within the 
Gulf of Alaska; however, like those tagged by Palacios et al. (2021), 
these whales mainly occurred in the Gulf of Alaska outside of the 
Navy's planned training period of April to October. Three of the 
whales' transits between Sakhalin Island, Russia and the Eastern North 
Pacific occurred during the fall and winter. A return trip to Russia 
from Baja California, Mexico by one of the three whales took place from 
February to May 2012. While it is not completely clear, based on Figure 
1 of Mate et al. (2015), it appears likely that the whale had crossed 
the Gulf of Alaska by April or in early April. While there are 
movements and interchange between the Eastern and Western North Pacific 
gray whales, as noted by the Commission, including migration of Western 
North Pacific gray whales through the Gulf of Alaska, as noted in Table 
4 of the proposed rule (87 FR 49656, August 11, 2022), their occurrence 
in the TMAA is rare. Given the occurrence information described above 
and the very low population estimate of Western North Pacific gray 
whales (290 whales in comparison to 26,960 Eastern North Pacific gray 
whales), NMFS has not added take of Western North Pacific gray whales 
to this final rule.
    Comment 8: For Baird's beaked whales, the Navy used a presumed 
density of 0.0005 whales/km\2\ from Waite (2003) based on a single 
sighting of four Baird's beaked whales. The Commission stated that this 
density estimate is of little value for reasons outlined in its January 
4, 2021 letter commenting on the 2020 GOA DSEIS/OEIS. In addition, the 
Navy specified that six visual sightings and 32 acoustic detections of 
Baird's beaked whales occurred during the 2013 survey in the TMAA 
(Department of the Navy 2021). Rone et al. (2014) also noted that 
Baird's beaked whales often travel in large groups. The Navy further 
specified average group size as 8.08 for Baird's beaked whales, 2.04 
for Cuvier's beaked whales, and 6 for Stejneger's beaked whales (see 
Table 26 in Department of the Navy, 2020a). As such, the Commission 
asserts that the density from Waite (2003) is a vast underestimate.
    The Commission further states that Rone et al. (2014) documented 
the first fine-scale habitat use of a tagged Baird's beaked whale in 
the region. The tagged individual showed the importance of seamount 
habitat, remaining approximately nine days, presumably foraging, within 
a relatively small geographic range inside the TMAA, with approximately 
six of those days spent in the vicinity of a single seamount (Rone et 
al., 2014). The greatest density of Cuvier's beaked whales also was 
attributed to the seamount stratum based on Yack et al. (2015). At a 
minimum, the stratum-specific densities for Cuvier's beaked whales 
should have been used as surrogates for Baird's beaked whales, with the 
understanding that the Cuvier's beaked whale densities may still be an 
underestimate based on the larger group size of Baird's beaked whales. 
The Commission recommended that NMFS use the three stratum-specific 
densities of Cuvier's beaked whales as surrogates for Baird's beaked 
whales and re-estimate the numbers of takes accordingly for the final 
rule.
    Response: The Navy developed a hierarchical system, described in 
each

[[Page 615]]

of the density technical reports, for identifying and selecting the 
best available density data. As described in Section 2.2.2 of the 
Density Technical Report for the GOA, the density value of a surrogate 
species can be used as a proxy value when species-specific density data 
are not available. A density estimate for Baird's beaked whale is 
available based on sighting data collected within the GOA; therefore, 
the use of density estimates for a surrogate species would not be 
consistent with the established hierarchy or the best scientific 
information available. NMFS and the Navy will update density estimates 
for Baird's beaked whale in the future if more recent survey data 
become available. Additionally, take estimates could be modified if 
other information supported it--however, no such information suggests 
that the estimated and authorized take are not appropriate, and 106 
annual takes continues to represent the best available science.
    Comment 9: The Commission stated that the Navy indicated that it 
used data derived from Hobbs and Waite (2010) to characterize harbor 
porpoise density in various strata based on published depth 
distributions (Department of Navy, 2021). The Navy did not stipulate 
where those depth strata delineations originated or what density from 
Hobbs and Waite (2010) was used. Hobbs and Waite (2010) provided an 
uncorrected density of 0.062 porpoises/km\2\ for GOA and a corrected 
abundance of 31,046 porpoises for the 158,733 km\2\ area surveyed (see 
Table 2), which would result in a corrected density of 0.198 porpoises/
km\2\. Both densities are greater than the 0.0473 porpoises/km\2\ that 
Navy used for the GOA (Department of the Navy, 2021). If NMFS considers 
the data in Hobbs and Waite (2010) to be the best available science, 
the Commission recommends that NMFS use the corrected density of 0.198 
porpoises/km\2\ from Hobbs and Waite (2010) for the 100 to 200-m 
isobath stratum and re-estimate the numbers of takes accordingly for 
harbor porpoises in the final rule.
    Response: Hobbs and Waite (2010) estimated the abundance of the GOA 
harbor porpoise stock based on aerial surveys conducted in the summer 
of 1998. The surveys were conducted along transect lines that ran from 
shore (including inlets, straits, and sounds) out to the 1,000 m depth 
contour, and were concentrated in nearshore areas where harbor porpoise 
are known to occur. Once corrected for perception and availability 
bias, Hobbs and Waite (2010) estimated a total of 31,046 harbor 
porpoise in the GOA stock (i.e., a density estimate of 0.1956 animal/
km\2\ based on a study region of 158,733 km\2\). Hobbs and Waite (2010) 
note that, despite the ranges of depth surveyed in the GOA, harbor 
porpoise were present primarily in waters less than 100 m in depth, 
which is consistent with aerial surveys off the U.S. West Coast where 
porpoise are mainly found in 20-60 m depth (Carretta et al., 2001). 
Based on these data, it was assumed 90 percent of the harbor porpoise 
are found in waters up to 100 m depth, 10 percent in waters from 100 
from 200 m depth, and few in waters from 200 to 1,000 m depth.
    Given their nearshore distribution, it would not be appropriate to 
use an overall harbor porpoise density estimate of 0.1956 animal/km\2\ 
for analysis in the GOA TMAA; density estimates need to be derived 
specific to the depth ranges where they are known to occur. To derive 
density estimates, depth strata were identified consistent with Hobbs 
and Waite (2010) and are shown below for waters within the GOA TMAA (to 
be consistent with the survey coverage of Hobbs and Waite (2010), the 
areas included nearshore regions within inlets, straits, and sounds). 
The total area within the 1,000 m depth contour = 101,588.64 km\2\.
    GOA TMAA depth distribution:

<100 m = 39,332.23 km\2\
100-200 m = 42,020.44 km\2\
200-1,000 m = 20,235.97 km\2\
TOTAL = 101,588.64 km\2\

    Based on the Hobbs and Waite (2010) density estimate of 0.1956 
animal/km\2\, approximately 19,871 harbor porpoise could occur within 
the TMAA. Based on these values, the following density estimates were 
calculated using the estimate of 19,871 harbor porpoises, the 
percentages noted above, and the area of each depth strata in the GOA 
TMAA.
GOA harbor porpoise density estimates:

<100 m = 0.4547 animals/km\2\
100-200 m = 0.0473 animals/km\2\
200-1,000 m = 0.00001 animals/km\2\

    Comment 10: The Commission stated that the Navy used abundance 
estimates divided by given areas to estimate densities, and the areas 
used were again inconsistent among species. For Northern fur seal, the 
Commission recommended that NMFS (1) specify why the Navy chose to use 
the GOA Large Marine Ecosystem (LME) area rather than the U.S. 
Geological Service (USGS) GOA area, (2) use the most recent northern 
fur seal abundance estimate of 626,618 rather than 620,660, (3) 
determine whether the information in the text or in Table 10-2 in 
Department of the Navy (2021) is correct regarding the assumed 
delineations of juvenile northern fur seals by sex and re-estimate the 
abundances provided in Table 10-3 based on the most recent abundance 
estimate and the correct delineation assumptions, (4) apply to 
September and October the same assumptions that were made regarding 
juveniles of both sexes for August, and (5) re-estimate the densities 
in Table 10-4 and the numbers of takes of northern fur seals in the 
final rule.
    Response: We first note that take estimation is not an exact 
science. There are many inputs that go into an estimate of marine 
mammal exposure, and the data upon which those inputs are based come 
with varying levels of uncertainty and precision. Also, differences in 
life histories, behaviors, and distributions of stocks can support 
different decisions regarding methods in different situations. Further, 
there may be more than one acceptable method to estimate take in a 
particular situation. Accordingly, while the applicant bears the 
responsibility of providing by species or stock the estimated number 
and type of takes (see 50 CFR 216.104(a)(6)) and NMFS always ensures 
that an applicant's methods are technically supportable and reflect the 
best available science, NMFS does not prescribe any one method for 
estimating take (or calculating some of the specific take estimate 
components that the commenter is concerned about). NMFS reviewed the 
areas, abundances, and correction factors used by the Navy to estimate 
take for the GOA Study Area and concurs that they are appropriate. 
While some of the suggestions the commenter makes could provide 
alternate valid ways to conduct the analyses, these modifications are 
not required in order to have equally valid and supportable analyses. 
In addition, we note that (1) some of the specific recommendations that 
the commenter makes in this comment and others are largely minor in 
nature within the context of our analysis (e.g., abundance estimate of 
626,618 rather than 620,660) and (2) even where the recommendation is 
somewhat larger in scale, given the ranges of the majority of these 
stocks, the size of the stocks, and the number and nature of pinniped 
takes, recalculating the estimated take for any of these pinniped 
stocks using the commenter's recommended changes would not change NMFS' 
assessment of impacts on the rates of recruitment or survival of any of 
these stocks, or the negligible impact determinations. Below, and in 
subsequent comment responses, we address the commenter's issues in more 
detail.
    The Navy adopted new methodologies and densities based on the best 
available science to improve the Navy's pinniped

[[Page 616]]

density estimates in the GOA and Northwest Training and Testing (NWTT) 
Study Areas. NMFS has reviewed the Navy's analysis and choices in 
relation to these comments and concurs that they are technically sound 
and reflect the best available science. The same approach taken for the 
pinniped density estimates in the NWTT Study Area was applied to 
density estimates in the GOA Study Area, including the use of haulout 
factors, telemetry data, and age and sex class distinctions (as data 
permitted). One difference was the application of a growth rate used to 
calculate abundances for some pinniped species in the NWTT Study Area. 
Applying an annual growth rate for pinniped species in the GOA was 
determined to be unnecessary or inappropriate based on discussions with 
pinniped subject matter experts at the NMFS Alaska Fisheries Science 
Center's Marine Mammal Lab. As was done in the NWTT Study Area, the 
Navy estimated seasonal in-water abundances for each species and 
divided those abundances by an area representing the distribution of 
each pinniped species. It would have been inappropriate and less 
accurate to assume all pinniped species were distributed equally over 
the same area (e.g., the GOA LME). For example, it would not have been 
representative of species occurrence to distribute harbor seals over 
the GOA LME to calculate density; however, the GOA LME was 
representative of the northern fur seal distribution.
    The percentages of northern fur seals occurring in the GOA LME 
presented in Table 10-2 are consistent with the information presented 
in the text of the Density Technical Report (U.S. Department of the 
Navy, 2021). The percentages for January through March were not shown 
in Table 10-2 because the Navy only presented densities for the period 
relevant to the planned training in the GOA Study Area (April through 
October). The percentages for January through April (equivalent to the 
data in Table 10-2) are provided in the table below.

                Table 4--Monthly Percentages of Age and Sex Classes of Northern Fur Seal in the Gulf of Alaska LME From January to April
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                            Eastern Pacific stock                             California
                                                                ----------------------------------------------------------------------------    stock
                                                                                           Juvenile     Juvenile                            ------------
                             Month                                  Adult       Adult     females (2    males (2
                                                                   females      males     and 3 year   and 3 year   Yearlings*      Pups         Pups
                                                                  (percent)   (percent)     olds;         old;       (percent)    (percent)   (percent)
                                                                                           percent)     percent)
--------------------------------------------------------------------------------------------------------------------------------------------------------
January........................................................          20          25           35           25            10          10           50
February.......................................................          20          20           20           20            10          10           50
March..........................................................          25          25           25           10            15          15           50
April..........................................................          15          15           35           10            15          15           50
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Assumes yearlings, which are not included in Zeppelin et al. (2019) and pups in the Eastern Pacific stock have the same month percentages through
  June.

    As described in the text of the Density Technical Report, the 
average percentage from January through April is 29 percent for 
juvenile females and 16 percent for juvenile males. Those averages were 
used for May and June for females and males, respectively. The process 
for estimating juvenile abundances, as presented in Table 10-2, is 
described in the text of the Density Technical Report. For example, the 
abundance of juvenile females is calculated as:
    Abundance = 620,660 x 0.085 x 0.35 = 18,456 juvenile female fur 
seals; where 8.5 percent is the class percentage of the stock (Density 
Technical Report Table 10-1, see footnote 2) and 35 percent is the 
portion of the class occurring in the Study Area in April (Table 10-2).
    The estimates of monthly abundances, including for juveniles, were 
validated by pinniped scientists at the Alaska Fisheries Science 
Center's Marine Mammal Lab, several of whom are co-authors on the paper 
by Zeppelin et al. (2019). The paper does not provide occurrence data 
for September, and, as shown in Figure 4 of the paper, the abundance of 
juveniles in the GOA in October is at or near zero.
    Comment 11: The Commission stated that it is unclear why the Navy 
did not forward-project the abundance estimates of Western Distinct 
Population Segment (wDPS) Steller sea lions to at least 2021, as trend 
data are available in NMFS' 2019 SAR and remain the same through 2021 
(Muto et al., 2022). They also request clarification as to why the Navy 
used Fritz et al. (2016) for the abundance estimates for western and 
eastern Steller sea lions. Those abundances were from surveys conducted 
in 2015 and have been updated by Sweeney et al. (2018 and 2019) as 
referenced in NMFS' 2019, 2020, and 2021 SARs. The Commission 
recommended that NMFS re-estimate (1) the Steller sea lion densities 
for the western DPS based on abundance data from Sweeney et al. (2018 
and 2019) rather than Fritz et al. (2016) and forward-project the 
abundance estimates into 2022 using the trend data provided in NMFS' 
2021 SAR, and (2) the number of Steller sea lion takes.
    Response: In the NWTT Study Area, the Navy used an annual growth 
rate to estimate densities for some pinniped species to account for 
abundance estimates reported in the SARs that were based on older 
survey data or when abundance estimates were no longer supported by the 
SAR. The intent of applying a growth rate was to estimate an abundance 
to the present time (i.e., at the time densities were being 
calculated). Growth rates were not used to ``forward project'' 
abundance estimates into the future, but to bring estimates up to the 
present if a reliable growth rate was available and appropriate to use 
for the species and location. A similar process was considered for 
estimating densities in the GOA Study Area; however, the Navy, 
following discussions with pinniped scientists at the NMFS Alaska 
Fisheries Science Center's Marine Mammal Lab, determined that applying 
a growth rate (including the trend data provided in NMFS' 2021 SAR) 
would not be appropriate for pinniped species occurring in the GOA, 
because available abundance estimates were considered accurate and 
representative.
    While the SARs do reference more recent surveys (Sweeney et al., 
2018, 2019), there is no substantial difference in the relevant 
abundance data reported

[[Page 617]]

by Sweeney et al. (2017, 2018, 2019) and Fritz et al. (2016). Sweeney 
et al. (2018) states that, ``there were no--or limited--new data 
collected for the GOA regions in 2018.'' Table 1 in Sweeney et al. 
(2018) shows that there were only two sites in the Central Gulf that 
were surveyed (and they were surveyed on a single day) and no sites in 
the Eastern Gulf that were surveyed. Figure 8 (pups) shows that the 
realized pup count is approximately the same as the pup count reported 
by Fritz et al. (2016) in Table 1. In both cases, the totals reported 
by Fritz et al. (2016) are higher. Given a lack of new data and that 
abundance estimates from both sources are similar, Sweeney et al. 
(2018) should not be considered a superior source of abundance data for 
Steller sea lions in the Eastern Gulf and Central Gulf regions. Sweeney 
et al. (2017) reports more extensive survey data for the Eastern Gulf 
and Central Gulf than Sweeney et al. (2018); however, Figure 7 of the 
2017 paper shows that realized pup counts are similar to those reported 
by Sweeney et al. (2018) and lower than those provided by Fritz et al. 
(2016). Lastly, the data, analysis, and discussion presented by Fritz 
et al. (2016) are more comprehensive than the abbreviated information 
presented by Sweeney et al. (2017, 2018) and include information 
specific to each sub-region (e.g., Central Gulf and Eastern Gulf) 
within the Western DPS. Given the similarity in abundances estimates, 
with the abundances in Fritz et al. (2016) more conservative for the 
Navy's analysis, no meaningful change in the density of Western DPS 
Steller sea lions would result from recalculating densities based on 
Sweeney et al. (2017, 2018, 2019).
    A small area east of the 144[deg] W longitude line, which defines 
the DPS boundary for Steller sea lions, overlapped with a 
conservatively sized area used by the Navy to delineate where species' 
densities were needed for modeling. The ``density area'' extended well 
beyond the TMAA and the Navy's area of potential effects; however, only 
densities inside the TMAA were reported in the Density Technical 
Report. The Navy estimated two seasonal densities for the Eastern DPS 
of Steller sea lions in the portion of the density area defined by the 
144[deg] W longitude line and the 500 m isobath (see table below).

      Table 5--Seasonal Densities for Eastern DPS Steller Sea Lions
------------------------------------------------------------------------
            Eastern DPS                         DPS area name
------------------------------------------------------------------------
34,196............................  Abundance.
63 percent........................  May-August percent in-water (haulout
                                     factor).
75 percent........................  April, September-October percent in-
                                     water (haulout factor).
21,543............................  May-August in-water abundance.
25,647............................  April, September-October in-water
                                     abundance.
90,796............................  Area (km\2\)
0.2373............................  May-August density (animals/km\2\)
0.2825............................  April, September-October density
                                     (animals/km\2\)
------------------------------------------------------------------------

    The portion of the Eastern DPS that overlaps with the density area 
and is in waters less than 500 m is approximately 100 km north of the 
TMAA. The portion of the Eastern DPS (east of the 144[deg] W longitude 
line) that overlaps with the TMAA is farther offshore and considerably 
deeper than 500 m and therefore has a zero density. Table 10-6 in the 
Density Technical Report specifically indicates densities are only 
provided inside the TMAA. Therefore, only a zero density for the 
Eastern DPS is reported in Table 10-6 for areas inside the TMAA. 
Additional text has been added to the Density Technical Report to 
explain this in greater detail. Prior to Navy analysis, NMFS reviewed 
and concurred with all densities used in the Density Technical Report.
    Comment 12: The Commission stated that in addition to the Navy's 
use of an inconsistent geographical area for elephant seals, the Navy 
used an outdated abundance estimate. The abundance estimate is from 12 
years ago, and the Commission asserted that it should have been 
forward-projected to at least 2021 based on the growth rate included in 
NMFS' 2019 SAR. Since then, NMFS has updated its elephant seal 
abundance estimate to 187,386 and its annual growth rate to 3.1 percent 
based on Lowry et al. (2020; Carretta et al., 2022). The Commission 
recommended that NMFS (1) specify why the Navy chose to use the USGS 
GOA area rather than the GOA LME area to estimate elephant seal 
densities in the preamble to the final rule, (2) use the most recent 
abundance estimate of 187,386 rather than 179,000 and forward-project 
it into 2022 using the trend data provided in NMFS' 2021 SAR, and (3) 
re-estimate the number of elephant seal takes in the final rule.
    Response: It is not clear what the Commission means by 
``inconsistent geographic areas for elephant seals.'' The USGS 
definition of the GOA represented the distribution information reported 
in Peterson et al. (2015) and Robinson et al. (2012), which were the 
primary sources used to define monthly elephant seal distributions, and 
was geographically more relevant to the TMAA than the GOA LME, which 
extends along the coast of southeast Alaska and British Columbia, 
Canada, far from the TMAA. Female northern elephant seals are primarily 
distributed throughout the eastern North Pacific following their post-
breeding and post-molting migrations. The GOA LME does not adequately 
represent their distribution, which begins with northward migrations 
from the Channel Islands off California and is concentrated with 
highest densities centered near the boundary between the sub-Arctic and 
subtropical gyres, south of the GOA LME (Robinson et al., 2012). Male 
elephant seals tend to forage and transit over the shelf closer to 
shore than females; however, they primarily migrate from the Channel 
Islands through the GOA to the Aleutian Islands. Unlike northern fur 
seals, which use much of the GOA LME during migration and their non-
breeding season, northern elephant seals occur outside of the GOA LME 
for a large portion of the year, making the GOA LME less relevant to 
their distribution and inadequate as an area representing their 
occurrence in a density calculation. Figure 1 in Peterson et al. (2015) 
illustrates how using the GOA LME as the density distribution area 
would be problematic. Telemetry data shows that some females migrated 
into the GOA LME off southeast Alaska and British Columbia, Canada 
following their post breeding (short) foraging trip; however, none of 
the tracks reached the GOA. Calculating densities in the southeast 
portion of the GOA LME was irrelevant to the Navy's analysis in the 
TMAA, and extrapolating densities from the southeast GOA LME into the 
TMAA would not have been accurate. The Navy searched for another 
geographic definition of the GOA that would encompass the entire TMAA 
but not extend as far south along the coast as the GOA LME. The USGS 
definition of the GOA met those requirements and allowed the Navy to 
more accurately estimate the proportion of elephant seals occurring in 
proximity to the TMAA based on the kernel density distribution data 
presented by Robinson et al. (2012). Based on these considerations, the 
Navy determined that the USGS definition of the GOA was more 
appropriate to use in calculating densities for northern elephant seals 
in the TMAA. NMFS reviewed and concurs with the Navy's determination. 
Please see Comment 10 for a response to the comment on the

[[Page 618]]

use of different geographic areas for different species.
    The Navy does not ``forward project'' abundances for any species, 
and NMFS concurs with this decision. A growth rate was applied to 
project an abundance to the present time (i.e., at the time densities 
were being calculated) for selected species in the NWTT Study Area. A 
similar process was considered for species in the GOA Study Area; 
however, the Navy, following discussions with pinniped scientists at 
the Alaska Fisheries Science Center's Marine Mammal Lab, determined 
that applying a growth rate would not be appropriate for pinniped 
species occurring in the GOA Study Area, because available abundance 
estimates were considered accurate and representative. NMFS concurs 
with this decision. Elephant seal researchers at the University of 
California Santa Cruz reviewed the Navy's elephant seal density 
estimates and confirmed the estimates as reasonable. The Navy is aware 
that the elephant seal abundance estimate in the SAR is older, and the 
Navy will continue to seek updated information on elephant seal 
abundance.
    Further, as explained in more detail in response to Comments 10 and 
14, take estimation is not an exact science, and updating the density 
using the most recent northern elephant seal abundance estimate of 
187,386 rather than 179,000 is not required in order to have an equally 
valid and supportable analysis. The change would be minor in nature 
within the context of our analysis, and recalculating the estimated 
take using the commenter's recommended changes would not change NMFS' 
assessment of impacts on the rates of recruitment or survival of any of 
these stocks, or the negligible impact determinations.
    Comment 13: The Commission stated that for harbor seals, the Navy 
indicated that it derived the proportion of the total population 
estimates in Table 10-10 of Department of the Navy (2021) from data 
provided by model A in Table 2 of Hastings et al. (2012). While 
Hastings et al. (2012) provided survival estimates of various age 
classes for seals on Tugidak Island in Table 2, they did not provide 
relative age-class proportions for the population. The Navy also used 
abundance estimates from 2015-2018 for the four stocks. As for other 
pinniped species, those estimates should have been forward-projected to 
at least 2021 based on the trend data available in NMFS' 2019 SAR. In 
addition, the Navy did not provide references regarding its assumption 
that harbor seals would be in the water for 50 percent of the time from 
June through September and for 60 percent of the time in April, May, 
and October. Boveng et al. (2012) indicated that the proportion of 
seals hauled out in Cook Inlet peaked at 43 percent in June compared to 
32 percent in October. Those haul-out proportions would equate to 57 
percent of seals in the water in June and 68 percent of the seals in 
the water in October--both of which are greater than the Navy's 
assumptions. For simplicity, the Navy could have used 60 and 70 percent 
rather than 50 and 60 percent. The Commission recommended that NMFS (1) 
re-estimate the densities of harbor seals based on the abundance data 
forward-projected to 2022 using the trend data provided in NMFS' 2021 
SAR and based on 60 percent of seals being in the water from June 
through September and 70 percent of the seals being in the water in 
April, May, and October as denoted in Boveng et al. (2012) and (2) re-
estimate the number of harbor seal takes in the final rule.
    Response: The Navy calculated relative age class proportions for 
harbor seal using survival rates and assuming an annual increase of 
1,234 harbor seals per year for the South Kodiak stock. The annual 
increase was based on the 8-year trend estimate from the SAR (Muto et 
al., 2019). Projections were made out to 35 years, and age class 
proportions were calculated based on the relative abundances in this 
hypothetical population after 35 years. This part of the process was 
not explained in detail in the Density Technical Report (November 
2020), but the approach was reviewed by pinniped scientists at the 
Alaska Fisheries Science Center's Marine Mammal Lab and deemed a 
reasonable approach for determining relative proportions of each age 
class represented in the four relevant harbor seal stocks. Additional 
text was added to the March 2021 Density Technical Report to outline 
this process in more detail.
    The abundances for the four stocks used in the density calculations 
are the abundances in the 2019 final SAR (Muto et al., 2020b) and were 
the most recent abundances available at the time the densities were 
derived. The abundance estimates were provided to the Navy by the 
Alaska Fisheries Science Center's Marine Mammal Lab in advance of being 
updated in the SAR. The Navy, following discussions with pinniped 
scientists at the Alaska Fisheries Science Center's Marine Mammal Lab, 
determined that applying a growth rate would not be appropriate for 
pinniped species occurring in the GOA Study Area because available 
abundance estimates are considered accurate and representative, and 
particularly in the case of harbor seals, very recent. NMFS reviewed 
and concurs with all densities used in the Density Technical Report.
    The haulout factors used to estimate the number of harbor seals in 
the water were adapted from Withrow and Loughlin (1995), who estimated 
that harbor seals were hauled out 58 percent of the time (42 percent in 
water) during molting season (August-September) on Grand Island in 
southeast Alaska; Pitcher and McAllister (1981), who estimated seals 
were in the water 50 percent of the time during pupping season and 59 
percent during molting season on Kodiak Island; and Withrow et al. 
(1999) in Withrow et al. (1999) who reported seals were hauled out 52 
percent of the time (48 percent in water) at Pedersen and Aialik 
glaciers on the Kenai Peninsula. These references report haulout data 
from the GOA region and are consistent in their estimates. After 
reviewing Boveng et al. (2012), it appears that the haulout correction 
factor for October may be 20 percent not 32 percent, as noted in the 
comment and the abstract (see Table 4 in Boveng et al. (2012)). While 
similar haulout percentages have been reported for harbor seals 
elsewhere for late fall or winter (Withrow and Loughlin, 1995; Yochem 
et al., 1987), this proportion (i.e., 20 percent hauled out and 80 
percent in the water) appears to be somewhat of an anomaly for the 
region based on the other studies cited above. Note that the Navy's 
proposed training activities would occur between April and October (not 
in late fall or winter) and have historically occurred in late spring 
or summer. For August, a timeframe more relevant to the Proposed 
Action, Boveng et al. (2012) qualify their results by noting that the 
number of seals hauled out in August (i.e., 35 percent) was expected to 
be higher, consistent with other survey results, and that the lower 
percentage was likely due to tags falling off during the molt in 
August, limiting available data and leading the authors to use 
mathematical functions to interpolate the August data and correct their 
abundance estimate (i.e., effectively discounting their tag-based 
haulout data). They conceded that the approach outlined in the paper 
likely underestimates the proportion of seals hauled out in August (see 
page 31 of Boveng et al. (2012)) and that the proportion of seals 
hauled out during molting season is often higher than during pupping 
season. Taking this reasoning into consideration, estimating that 50 
percent instead of 57 percent of

[[Page 619]]

seals would be in the water for June through September (pupping and 
molting seasons) is a reasonable approximation and is consistent with 
the references cited above (Pitcher and McAllister, 1981). Lastly, J. 
London, one of the co-authors of Boveng et al. (2012), reviewed the 
Navy's density calculations for harbor seals in the GOA and concurred 
that the density estimates were appropriate for the Navy's model. The 
Navy has updated the Density Technical Report to better explain the 
sources for the haulout factors that were used in the analysis. NMFS 
has reviewed the Navy's analysis and choices in relation to this 
comment and concurs that they are technically sound and reflect the 
best available science.
    Comment 14: The Commission stated that rather than use the older 
abundance estimates that informed the densities in Department of the 
Navy (2021), NMFS correctly used abundance estimates from the most 
recent SARs, including the 2021 SARs (Carretta et al., 2022, Muto et 
al., 2022), in its negligible impact determination analysis (Tables 41-
46 in the proposed rule; 87 FR 49656; August 11, 2022). NMFS specified 
in the preamble to the proposed rule that those 2021 SARs represent the 
best available science (85 FR 49666; August 11, 2022) and then used the 
associated abundances to inform its analysis. NMFS should not consider 
one abundance estimate the best available science for its density 
estimates (85 FR 49716; August 11, 2022) and another abundance estimate 
best available science for its negligible impact determination analysis 
for the same species (85 FR 49666; August 11, 2022). The Commission 
stated that this approach is inconsistent with the tack taken for other 
Navy rulemakings (e.g., Atlantic Fleet Training and Testing (AFTT)). 
For its negligible impact determinations in the AFTT rulemaking, NMFS 
indicated that it compared the predicted takes to abundance estimates 
generated from the same underlying density estimate instead of certain 
SARs, which are not based on the same underlying data and would not be 
appropriate for the analysis (e.g., Tables 72-77; 83 FR 57076 and 
57214). It is clear that the more recent SAR data represent best 
available science, further supporting the need for NMFS to correct the 
various pinniped density estimates using those data. The Commission 
recommends that NMFS use the same species-specific abundance estimates 
to both derive the densities and inform its negligible impact 
determinations for the various pinniped species in the final rule.
    Response: NMFS referenced the latest abundance estimates for all 
species and stocks, as included in the 2021 final SARs, in its 
negligible impact determinations. NMFS recognizes that mathematically, 
it is most appropriate to compare a density/take estimate to an 
abundance estimate that is derived from the same data. However, in the 
instances in this rule where a density/take estimate calculated using 
an older abundance estimate was compared to a newer abundance estimate, 
the result is very similar as if the take estimate were compared to the 
same abundance estimate that the corresponding density was derived 
from. As described above in responses to Comments 10 through 13, older 
abundance estimates were used to derive some densities given that those 
data were the best available at the time, and it is impractical to 
update the densities each time a new abundance estimate is generated 
(which could be up to two times per year, as an estimate could 
potentially be updated in both a draft and final SAR each year). 
Further, neither take estimation nor negligible impact determinations 
is an exact science. While NMFS does reference the abundance estimates 
of the stocks in the negligible impact analyses, the comparison between 
the authorized take and abundance for a given stock is meant to provide 
a relative sense of where a larger portion of a species or stock is 
being taken by Navy activities, where there is a higher likelihood that 
the same individuals are being taken on multiple days, and where that 
number of days might be higher or sequential. This comparison between 
authorized take and the stock abundance is not used for making a small 
numbers determination for this authorization, as authorizations for 
military readiness activities do not require a small numbers 
determination. Therefore, referencing an abundance estimate in a 
negligible impact determination that is more recent than the abundance 
estimate used to derive a density would not have an impact on the 
determination unless there is a vast difference in the two abundance 
estimates, and that is not the case here.
    Comment 15: A commenter asserted that, as explained in the 
Commission's letter, many of NMFS' density and take estimates are 
inaccurate and underestimated. The Commission specifically recommended 
that NMFS clarify and ``re-estimate the numbers of marine mammal 
takes.'' The commenter asserted that NMFS' underestimates are apparent 
in regard to many of the seal, sea lion, and porpoise species because 
NMFS estimates that there will be zero takes for those species when all 
other active LOAs in the area estimate large numbers of takes for those 
species. Authorizing the take of even more marine mammals will have a 
non-negligible impact on the species or stocks under the MMPA because 
it will likely adversely affect the annual rates of recruitment or 
survival. Thus, NMFS should deny the Navy's LOA application.
    Response: NMFS' responses to Comments 6 through 13 address the 
Commission's density and take estimate recommendations. Regarding take 
of seals, sea lions, and porpoises, NMFS and the Navy carefully 
considered the potential for take of all marine mammal species that may 
occur in the GOA Study Area and the TMAA portion of the GOA Study Area 
(the portion of the GOA Study Area in which the use of sonar and other 
transducers and explosives at or near the surface (within 10 m above 
the water surface) will occur) in particular. Numerous species are not 
expected to occur in the TMAA, as described in the Species Not Included 
in the Analysis section of this final rule. While harbor porpoise, 
Steller sea lion, California sea lion, harbor seal, and ribbon seal 
could occur in the GOA Study Area, modeling indicates that take of 
these species is unlikely to result from the use of sonar and other 
transducers or explosives at or near the surface (within 10 m above the 
water surface).
    Further, the comparison of the take estimate for the Navy's GOA 
training activities to take authorizations for other activities in 
Alaska is not appropriate given the differences in location among these 
activities and the likelihood of occurrence of various species at these 
project sites. The Navy's Gulf of Alaska activities are planned for the 
GOA Study Area, an offshore area in the Gulf of Alaska (see Figure 1 of 
the proposed rule; 87 FR 49656; August 11, 2022), while the projects 
that the commenter has referenced are occurring either at a location on 
the Alaska shoreline or in the Arctic Ocean. Given that occurrence of 
marine mammals at shoreline locations is site specific, and the 
distance of the Arctic Ocean from the GOA Study Area, it is incorrect 
to assume that occurrence of marine mammals would be similar at all 
project sites. For the reasons described above, including in the 
responses to Comments 6 through 13re, authorizing additional takes of 
marine mammals beyond that proposed for authorization in the proposed 
rule is not warranted, and the authorized takes will have a negligible 
impact on the relevant species and stocks as described in the Analysis 
and

[[Page 620]]

Negligible Impact Determination section of this final rule.

Mitigation

    Comment 16: A commenter stated that when the Navy's activity 
occurs, utmost caution should be exercised in the whereabouts of marine 
mammals. The commenter further suggested that the Navy should reduce 
the amount of incidental take of marine mammals.
    Response: As discussed in the Mitigation Measures section of this 
final rule, and in Chapter 5 (Mitigation) of the 2022 GOA FSEIS/OEIS, 
the Navy will implement extensive mitigation to avoid or reduce 
potential impacts from the GOA activities on marine mammals. The 
mitigation measures would reduce the probability and/or severity of 
impacts expected to result from acute exposure to acoustic sources or 
explosives, ship strike, and impacts to marine mammal habitat. 
Specifically, the Navy would use a combination of delayed starts, 
powerdowns, and shutdowns to avoid mortality or serious injury, 
minimize the likelihood or severity of PTS or other injury, and reduce 
instances of TTS or more severe behavioral disruption caused by 
acoustic sources or explosives. The Navy would also implement two 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 
foraging or migration, particularly for North Pacific right whales, 
humpback whales, and gray whales.
    Comment 17: A commenter stated that as part of the Navy's 
mitigation efforts, the Navy requires all bridge watch standers and 
other applicable personnel to complete Marine Species Awareness 
Training (MSAT) prior to standing watch or serving as a lookout. 
However, the commenter stated that absent is any mention of refresher 
training conducted prior to any major exercises such as the carrier 
strike group (CSG) exercise. The commenter states that given their 
experience as a former Surface Warfare Officer and Anti-Submarine 
Warfare Officer (ASWO), they know that MSAT training is generally 
required annually and that knowledge in this area among bridge watch 
standers and especially lookouts is low and quickly atrophies after 
training. The commenter states that while it would be unreasonable to 
suggest conducting training prior to every exercise, special 
consideration should be given to major CSG exercises. Major CSG 
exercises include multiple ships often testing various capabilities 
where the risk of taking marine mammals is elevated and can only 
properly be mitigated if the watch standers are freshly trained. 
Therefore, the commenter recommended MSAT training be reconducted and 
documented prior to any major CSG exercise.
    Additionally, given the increased use of active sonar during major 
CSG exercises, the commenter recommended the Combat Acoustics Division, 
ASWO, and Surface Ship Anti-Submarine Warfare Specialist conduct Sonar 
Positional Reporting System training prior to any major CSG exercises. 
The commenter asserted that this will ensure that active sonar use is 
properly documented and can be later reviewed if a marine mammal is 
significantly injured to determine if active sonar was a likely cause.
    Response: The Navy routinely refines its training modules to 
improve sailor professional knowledge and skills. It also seeks and 
provides lessons learned to units periodically on all the environmental 
compliance tools (Protective Measures Assessment Protocol (PMAP), Sonar 
POsitional ReporTing System (SPORTS), Marine Species Awareness Training 
(MSAT)). The Navy requires Lookouts and other personnel to complete 
their assigned environmental compliance responsibilities (e.g., 
mitigation, reporting requirements) before, during, and after training 
activities. MSAT was first developed in 2007 and has since undergone 
numerous updates to ensure that the content remains current. The MSAT 
product was approved by NMFS and most recently updated by the Navy in 
2018. In 2014, the Navy developed a series of educational training 
modules, known as the Afloat Environmental Compliance Training program, 
to ensure Navy-wide compliance with environmental requirements. The 
Afloat Environmental Compliance Training program, including the updated 
MSAT, helps Navy personnel from the most junior Sailors to Commanding 
Officers gain a better understanding of their personal environmental 
compliance roles and responsibilities.
    MSAT, PMAP, and SPORTS training are required for personnel both 
upon reporting aboard (e.g., newly assigned to a command) and annually 
thereafter as per Navy policy. Additional MSAT may be required again 
within an annual period for special circumstance (e.g., large crew 
transfers, regional ship strikes, as mandated by internal Navy exercise 
directions). In addition to the required use of PMAP to obtain the 
procedural and geographic mitigations prior to events in a CSG 
exercise, pre-exercise orders for exercises in the GOA and in other 
locations instruct review of MSAT at least once annually. Since each 
unit is on individual deployment and their own training schedule, 
additional training for individual units may occur as situations 
warrant (e.g., bridge team rotation). There are multiple tools for 
ships' personnel to utilize in support of these procedural 
requirements, including whale identification wheels. Navy has recently 
published a revised Lookout Training Handbook (NAVEDTRA 12968-E) to 
assist in the training of lookout skills and species identification. 
NMFS and the Navy continue to look for ways to improve lookout 
effectiveness through the adaptive management process. However, NMFS 
does not find it appropriate to include a requirement to conduct 
additional MSAT or SPORTS training prior to an exercise.
    Comment 18: A commenter stated that one of the most effective means 
to protect marine mammals from noise and disturbance is to impose time 
and area restrictions. The agency should consider additional mitigation 
and time and area restrictions, including but not limited to the 
specific recommendations outlined in its letter.
    Response: NMFS agrees that time and area restrictions are an 
effective tool for minimizing impacts of an activity on marine mammals. 
NMFS addressed the commenter's specific recommendations for additional 
mitigation in its responses to Comments 19 through 25 and Comments 27, 
28, and 30. Please see the Mitigation Measures section of this rule and 
Section 5.5 (Mitigation Measures Considered but Eliminated) of the 2022 
GOA FSEIS/OEIS for a full discussion of additional mitigation measures 
that were considered.
    Comment 19: A commenter recommended extending the mitigation areas 
to include a buffer zone to protect the biologically sensitive areas 
from received levels that are above the take threshold.
    Response: The mitigation areas included in the final rule and 
described in Chapter 5 (Mitigation) of the 2022 GOA FSEIS/OEIS 
represent the maximum mitigation within mitigation areas and the 
maximum size of mitigation areas that are practicable for the Navy to 
implement under their specified activity. Implementing additional 
mitigation (e.g., buffer zones that would extend the size of the 
mitigation areas) beyond what is included in the final rule is 
impracticable due to implications for safety, sustainability, and the 
Navy's ability to continue meeting its mission requirements. However, 
this Phase III rule includes a new mitigation area, the Continental 
Shelf and Slope Mitigation Area. Navy personnel will not detonate

[[Page 621]]

explosives below 10,000 ft altitude (including at the water surface) 
during training at all times in the Continental Shelf and Slope 
Mitigation Area (including in the portion that overlaps the North 
Pacific Right Whale Mitigation Area). Previously, the Navy's 
restriction on explosives applied seasonally within the North Pacific 
Right Whale Mitigation Area and within the Portlock Bank Mitigation 
Area. With the development of the Continental Shelf and Slope 
Mitigation Area, that restriction now applies across the entire 
continental shelf and slope out to the 4,000 m depth contour within the 
TMAA. Mitigation in the Continental Shelf and Slope Mitigation Area was 
initially designed to avoid or reduce potential impacts on fishery 
resources for Alaska Natives. However, the area includes highly 
productive waters where marine mammals (including humpback whales 
(Lagerquist et al., 2008) and North Pacific right whales) feed and 
overlaps with a small portion of the North Pacific right whale feeding 
BIA off of Kodiak Island. Additionally, the Continental Shelf and Slope 
Mitigation Area overlaps with a very small portion of the humpback 
whale critical habitat Unit 5, on the western side of the TMAA, and a 
small portion of humpback whale critical habitat Unit 8 on the north 
side of the TMAA. The Continental Shelf and Slope Mitigation Area also 
overlaps with a very small portion of the gray whale migration BIA. The 
remainder of the designated critical habitat and BIAs are located 
beyond the boundaries of the GOA Study Area. While the overlap of the 
mitigation area with critical habitat and feeding and migratory BIAs is 
limited, mitigation in the Continental Shelf and Slope Mitigation Area 
may reduce the probability, number, and/or severity of takes of 
humpback whales, North Pacific right whales, and gray whales in this 
important area (noting that the Navy's Acoustic Effects Model estimated 
zero takes for gray whales, though NMFS has conservatively authorized 
four takes by Level B harassment). Additionally, mitigation in this 
area will likely reduce the number and severity of potential impacts to 
marine mammals in general, by reducing the likelihood that feeding is 
interrupted, delayed, or precluded for some limited amount of time.
    When practicable, NMFS sometimes recommends the inclusion of 
buffers around areas specifically delineated to contain certain 
important habitat or high densities of certain species, to allow for 
further reduced effects on specifically identified features/species. 
However, buffers are not always considered necessary or appropriate in 
combination with more generalized and inclusive measures, such as 
coastal offsets or other areas that are intended to broadly contain 
important features for a multitude of species. In the case of this 
rulemaking, NMFS and the Navy have included two protective areas that 
will reduce impacts on multiple species and habitats and, as described 
above, limitations in additional areas is not practicable.
    Comment 20: A commenter recommended prohibiting active sonar in the 
Portlock Bank Mitigation Area.
    Response: Increasing the geographic mitigation requirements 
pertaining to the use of active sonar in the TMAA, either by adding a 
sonar restriction to Portlock Bank or expanding the size of the North 
Pacific Right Whale Mitigation Area is not practicable, for the reasons 
detailed in Section 5.5.1 (Active Sonar) of the 2022 GOA FSEIS/OEIS, 
which NMFS has reviewed and concurs with. However, mitigation for 
explosives was included in the 2020 GOA DSEIS/OEIS in a ``Portlock Bank 
Mitigation Area,'' and this area has since been expanded into the 
Continental Shelf and Slope Mitigation Area. (Please see the Mitigation 
Areas section of this final rule and Section 5.4 (Geographic Mitigation 
to be Implemented) of the 2022 GOA FSEIS/OEIS for additional details 
about the requirements in this area and the ecological benefits.)
    Comment 21: A commenter recommended moving the GOA Study Area 
activities to the fall, after September, which the commenter stated 
would avoid fishing seasons as well as primary whale feeding months. 
Alternatively, the Navy should adopt geographic mitigation shoreward of 
the continental shelf between June and September because that portion 
of the TMAA is near the biologically important feeding areas for North 
Pacific right whales, fin whale, humpback whales, and gray whales 
during those months.
    Response: As described in Section 5.4.3 (Operational Assessment) of 
the 2022 GOA FSEIS/OEIS, it would not be practical to shift the months 
of the Proposed Action due to impacts on safety, sustainability, and 
mission requirements. The exercise, Northern Edge, is a U.S. Indo-
Pacific Command (USINDOPACOM) sponsored exercise, led by Headquarters 
Pacific Air Forces. The joint service training exercise typically 
occurs every other year during odd number years for approximately a 
two-week period. The Navy has participated in this or its predecessor 
exercises for decades, and although naval warships and planes play a 
vital role in Northern Edge, the Navy does not determine the specific 
dates for conducting each exercise. USINDOPACOM determines exercise 
dates based on a number of factors, including weather conditions, 
safety of personnel and equipment, effectiveness of training, 
availability of forces, deployment schedules, maintenance periods, 
other exercise schedules within the Pacific region, and important 
environmental considerations. Although the Navy is unable to further 
restrict the months when training could be conducted in the GOA Study 
Area, the Navy is required to implement geographic mitigation in the 
North Pacific Right Whale Mitigation Area and the Continental Shelf and 
Slope Mitigation Area.
    Mitigation within the North Pacific Right Whale Mitigation Area is 
primarily designed to avoid or further reduce potential impacts to 
North Pacific right whales within important feeding habitat. The 
mitigation area fully encompasses the portion of the BIA identified by 
Ferguson et al. (2015) for North Pacific right whale feeding that 
overlaps the GOA Study Area (overlap between the GOA Study Area and the 
BIA occurs in the TMAA only) (see Figure 2 of the proposed rule; 87 FR 
49656; August 11, 2022). North Pacific right whales are thought to 
occur in the highest densities in the BIA from June to September. The 
Navy will not use surface ship hull-mounted MF1 mid-frequency active 
sonar in the mitigation area from June 1 to September 30, as was also 
required in the Phase II (2017-2022) rule (82 FR 19530; April 26, 
2017). The North Pacific Right Whale Mitigation Area is fully within 
the boundary of the Continental Shelf and Slope Mitigation Area, 
discussed below. Therefore, the mitigation requirements in that area 
also apply to the North Pacific Right Whale Mitigation Area. While the 
potential occurrence of North Pacific right whales in the GOA Study 
Area is expected to be rare due to the species' small population size, 
these mitigation requirements would help further avoid or further 
reduce the potential for impacts to occur within North Pacific right 
whale feeding habitat, thus likely reducing the number of takes of 
North Pacific right whales, as well as the severity of any disturbances 
by reducing the likelihood that feeding is interrupted, delayed, or 
precluded for some limited amount of time.
    Additionally, the North Pacific Right Whale Mitigation Area 
overlaps with a small portion of the humpback whale critical habitat 
Unit 5, in the southwest

[[Page 622]]

corner of the TMAA. While the overlap of the two areas is limited, 
mitigation in the North Pacific Right Whale Mitigation Area may reduce 
the number and/or severity of takes of humpback whales in this 
important area.
    The mitigation in this area would also help avoid or reduce 
potential impacts on fish and invertebrates that inhabit the mitigation 
area and which marine mammals prey upon. As described in Section 
5.4.1.5 (Fisheries Habitats) of the 2022 GOA FSEIS/OEIS, the productive 
waters off Kodiak Island support a strong trophic system from plankton, 
invertebrates, small fish, and higher-level predators, including large 
fish and marine mammals.
    As described in further detail in response to Comment 19, the 
Continental Shelf and Slope Mitigation Area is expected to reduce the 
probability, number, and/or severity of takes of humpback whales, North 
Pacific right whales, and gray whales in this important area (noting 
that no takes are predicted for gray whales). Additionally, mitigation 
in this area will likely reduce the number and severity of potential 
impacts to marine mammals in general, by reducing the likelihood that 
feeding is interrupted, delayed, or precluded for some limited amount 
of time.
    Comment 22: A commenter recommended capping the maximum level of 
activities conducted each year.
    Response: The commenters offer no rationale for why a cap is needed 
and nor do they suggest what an appropriate cap might be. The Navy is 
responsible under Title 10 of the U.S. Code for conducting the needed 
amount of testing and training to maintain military readiness, which is 
what they have proposed and NMFS has analyzed. Further, the MMPA states 
that NMFS shall issue MMPA authorizations if the necessary findings can 
be made, as they have been here. Importantly, as described in the 
Mitigation Areas section, the Navy will limit activities (active sonar, 
explosive use, etc.) to varying degrees in two areas that are important 
to sensitive species or for important behaviors in order to minimize 
impacts that are more likely to lead to adverse effects on rates of 
recruitment or survival.
    Comment 23: A commenter recommended increasing the exclusion zone 
because some animals are sensitive to sonar at low levels of exposure.
    Response: The commenter does not suggest what an appropriate 
exclusion zone size would be. The Navy, in coordination with NMFS, 
customized its mitigation zone sizes and mitigation requirements for 
each applicable training activity category or stressor. Each mitigation 
zone represents the largest area that (1) Lookouts can reasonably be 
expected to observe during typical activity conditions (i.e., most 
environmentally protective) and (2) the Navy can implement the 
mitigation without impacting safety or the ability to meet mission 
requirements. The current exclusion zones represent the maximum 
distance practicable for the Navy to implement during training within 
the TMAA, as described in Chapter 5 of the FSEIS/OEIS and, further, 
they encompass the area in which any marine mammal would be expected to 
potentially be injured. The active sonar mitigation zones also extend 
beyond the average ranges to temporary threshold shift for otariids and 
into a portion of the average ranges to temporary threshold shift for 
all other marine mammal hearing groups; therefore, mitigation would 
help avoid or reduce the potential for some exposure to higher levels 
of temporary threshold shift. This final rule includes procedural 
mitigation and mitigation areas to further avoid or reduce potential 
impacts from active sonar on marine mammals in areas where important 
behaviors such as feeding and migration occur.
    Comment 24: A commenter recommended imposing a 10-knot ship speed 
in Mitigation Areas to reduce the likelihood of vessel strikes.
    Response: Generally speaking, it is impracticable (because of 
impacts to mission effectiveness) to further reduce ship speeds for 
Navy activities, and, moreover, given the maneuverability of Navy ships 
at higher speeds and the presence of Lookouts, any further reduction in 
speed would be unlikely to reduce the already extremely low probability 
of a ship strike (which is not authorized, nor expected to occur in the 
GOA Study Area). The Navy is unable to impose a 10-knot ship speed 
limit because it would not be practical to implement and would not 
allow the Navy to continue meeting its training requirements due to 
diminished realism of training exercises, as detailed in Section 
5.3.4.1 (Vessel Movement) of the 2022 GOA FSEIS/OEIS. The Navy requires 
flexibility to use variable ship speeds for training, operational, 
safety, and engineering qualification requirements. Navy ships 
typically use the lowest speed practical given mission needs. NMFS has 
reviewed the Navy's analysis of additional restrictions and the impacts 
they would have on military readiness and concurs with the Navy's 
assessment that they are impracticable.
    The main driver for ship speed reduction is reducing the 
possibility and severity of ship strikes to large whales. However, even 
given the wide ranges of speeds from slow to fast that Navy ships have 
used in training in the GOA Study Area, there have been no documented 
vessel strikes of marine mammals by the Navy.
    As discussed in the 2016 GOA FSEIS/OEIS Section 5.1.2 (Vessel 
Safety), Navy standard operating procedures require that ships operated 
by or for the Navy have personnel assigned to stand watch at all times, 
day and night, when moving through the water (i.e., when the vessel is 
underway). A primary duty of watch personnel is to ensure safety of the 
ship, which includes the requirement to detect and report all objects 
and disturbances sighted in the water that may be indicative of a 
threat to the ship and its crew, such as debris, a periscope, surfaced 
submarine, or surface disturbance. Per safety requirements, watch 
personnel also report any marine mammals sighted that have the 
potential to be in the direct path of the ship, as a standard collision 
avoidance procedure. As described in Section 5.3.4.1 (Vessel Movement) 
of the 2022 GOA FSEIS/OEIS, Navy vessels are also required to operate 
in accordance with applicable navigation rules. Applicable rules 
include the Inland Navigation Rules (33 CFR part 83) and International 
Regulations for Preventing Collisions at Sea (72 Collision 
Regulations), which were formalized in the Convention on the 
International Regulations for Preventing Collisions at Sea, 1972. These 
rules require that vessels proceed at a safe speed so proper and 
effective action can be taken to avoid collision and so vessels can be 
stopped within a distance appropriate to the prevailing circumstances 
and conditions. In addition to standard operating procedures, the Navy 
implements mitigation to avoid vessel strikes, which includes requiring 
vessels to maneuver to maintain at least 500 yd distance from whales, 
and 200 yd or 100 yd distance away from other marine mammals (except 
those intentionally swimming alongside or choosing to swim alongside 
vessels, such as for bow-riding or wake-riding). Additionally, please 
see the Potential Effects of Vessel Strike section of the proposed rule 
(87 FR 49656; August 11, 2022) for discussion regarding the differences 
between Navy ships and commercial ships which make Navy ships less 
likely to affect marine mammals.
    When developing Phase III mitigation measures, the Navy analyzed 
the potential for implementing additional types of mitigation, such as 
vessel speed restrictions within the GOA Study Area.

[[Page 623]]

The Navy determined that based on how the training activities will be 
conducted within the GOA Study Area, vessel speed restrictions would be 
incompatible with practicability criteria for safety, sustainability, 
and training missions, as described in Chapter 5 (Mitigation), Section 
5.3.4.1 (Vessel Movement) of the 2022 GOA FSEIS/OEIS. However, this 
rule includes mitigation to further reduce the already low potential 
for vessel strike as described in the Mitigation Measures section of 
this final rule and in Chapter 5 of the 2022 GOA FSEIS/OEIS. 
Occurrences of large whales may be higher over the continental shelf 
and slope relative to other areas of the TMAA. The Navy would issue 
pre-event awareness messages to alert ships and aircraft participating 
in training activities within the TMAA to the possible presence of 
concentrations of large whales on the continental shelf and slope. 
Large whale species in the TMAA include, but are not limited to, fin 
whale, blue whale, humpback whale, gray whale, North Pacific right 
whale, sei whale, and sperm whale. To maintain safety of navigation and 
to avoid interactions with these species, the Navy will instruct 
vessels to remain vigilant to the presence of large whales that may be 
vulnerable to vessel strikes or potential impacts from training 
activities. Additionally, ships and aircraft will use the information 
from the awareness messages to assist their visual observation of 
applicable mitigation zones during training activities and to aid in 
the implementation of procedural mitigation.
    Comment 25: A commenter recommended that NMFS add mitigation for 
other marine mammal stressors such as dipping sonar and contaminants.
    Response: The Navy implements mitigation for active sonar, 
including dipping sonar, as outlined in Table 34 of this rule, and in 
Section 5.3.2.1 (Active Sonar) of the 2022 GOA FSEIS/OEIS. Expanding 
active sonar mitigation requirements would be impractical for the 
reasons detailed in Section 5.5.1 (Active Sonar) of the 2022 GOA FSEIS/
OEIS, which NMFS has reviewed and concurs with. As described in Section 
3.8.3.3 (Secondary Stressors) of the 2022 GOA FSEIS/OEIS, potential 
impacts of secondary stressors (including contaminants), were 
determined to be discountable, negligible, or insignificant, and not 
expected to result in the take of any mammal; therefore, mitigation for 
contaminants is not warranted.

Least Practicable Adverse Impact Determination

    Comment 26: The Commission recommended that NMFS--
     clearly separate its application of the least practicable 
adverse impact requirement from its negligible impact determination;
     adopt a clear decision-making framework that recognizes 
the species and stock component and the marine mammal habitat component 
of the least practicable adverse impact provision and always consider 
whether there are potentially adverse impacts on marine mammal habitat 
and whether it is practicable to minimize them;
     rework its evaluation criteria for applying the least 
practicable adverse impact standard to separate the factors used to 
determine whether a potential impact on marine mammals or their habitat 
is adverse and whether possible mitigation measures would be effective;
     address these concerns by adopting a simple, two-step 
analysis that more closely tracks the statutory provisions being 
implemented and, if NMFS is using some other legal standard to 
implement the least practicable adverse impact requirements, provide a 
clear and concise description of that standard and explain why it 
believes it to be ``sufficient'' to meet the statutory legal 
requirements; and
     adopt general regulations to govern the process and set 
forth the basic steps and criteria that apply across least practicable 
adverse impact determinations.
    Response: NMFS has made clear in this and other rules that the 
agency separates its application of the least practicable adverse 
impact requirement in the Mitigation Measures section from its 
negligible impact analyses and determinations for each species or stock 
in a separate section. Further, NMFS has made this separation clear in 
practice for years by requiring mitigation measures to reduce impacts 
to marine mammal species and stocks and their habitat for all projects, 
even those for which the anticipated take would clearly have a 
negligible impact, even in the absence of mitigation.
    In the Mitigation Measures section of this rule, NMFS has explained 
in detail our interpretation of the least practicable adverse impact 
standard, the rationale for our interpretation, and how we implement 
the standard. The method the agency is using addresses all of the 
necessary components of the standard and produces effective mitigation 
measures that result in the least practicable adverse impact on both 
the species or stocks and their habitat. The commenter has failed to 
illustrate why NMFS' approach is inadequate or why the commenter's 
proposed approach would be better, and we therefore decline to accept 
the recommendation.
    Also, in the Mitigation Measures section, NMFS has explained in 
detail our interpretation and application of the least practicable 
adverse impact standard. The commenter has recommended an alternate way 
of interpreting and implementing the least practicable adverse impact 
standard, in which NMFS would consider the effectiveness of a measure 
in our evaluation of its practicability. The commenter erroneously 
asserts that NMFS currently considers the effectiveness of a measure in 
a determination of whether the potential effects of an activity are 
adverse, but the commenter has misunderstood NMFS' application of the 
standard--rather, NMFS appropriately considers the effectiveness of a 
measure in the evaluation of the degree to which a measure will reduce 
adverse impacts on marine mammal species or stocks and their habitat, 
as a less effective measure will less successfully reduce these impacts 
on marine mammals. Further, the commenter has not provided information 
that shows that their proposed approach would more successfully 
evaluate mitigation under the least practicable adverse impact 
standard, and we decline to accept it.
    Further, NMFS disagrees with the commenter's assertion that 
analysis of the rule's mitigation measures under the least practicable 
adverse impact standard remains unclear or that the suggested 
shortcomings exist. The commenter provides no rationale as to why the 
two-step process they describe is better than the process that NMFS 
uses to evaluate the least practicable adverse impact that is described 
in the rule, and therefore we decline to accept the recommendation.
    Regarding the assertion that the standard shifts on a case-by-case 
basis, the commenter misunderstands the agency's process. Neither the 
least practicable adverse impact standard nor NMFS' process for 
evaluating it shifts on a case-by-case basis. Rather, as the commenter 
suggests should be the case, the evaluation itself is case-specific to 
the proposed activity, the predicted impacts, and the mitigation under 
consideration.
    Regarding the recommendation to adopt general regulations, we 
appreciate the recommendation and may consider the recommended approach 
in the future. However, providing directly relevant explanations of 
programmatic

[[Page 624]]

approaches or interpretations related to the incidental take provisions 
of the MMPA in a proposed incidental take authorization is an effective 
and efficient way to provide information to and solicit focused input 
from the public. Further, this approach affords the same opportunities 
for public comment as a stand-alone rulemaking would.

Monitoring

    Comment 27: A commenter recommended that NMFS improve detection of 
marine mammals with restrictions on low-visibility activities and 
alternative detection such as thermal or acoustic methods.
    Response: As described in Section 5.5.1 (Active Sonar) of the 2022 
GOA FSEIS/OEIS, which NMFS has reviewed and concurs with, although the 
majority of sonar use occurs during the day, the Navy has a nighttime 
training requirement for some active sonar systems. Training in both 
good visibility (e.g., daylight, favorable weather conditions) and low 
visibility (e.g., nighttime, inclement weather conditions) is vital 
because environmental differences between day and night and varying 
weather conditions affect sound propagation and the detection 
capabilities of sonar. After sunset and prior to sunrise, Lookouts and 
other Navy watch personnel employ night visual search techniques, which 
could include the use of night vision devices. The Navy requires 
flexibility in the timing of its use of active sonar and explosives in 
order to meet individual training schedules. In June and July, there 
are approximately 19 hours of daylight per day in the GOA; therefore, 
there are naturally fewer hours of available nighttime to be used for 
sonar training. Due to the already limited timeframe of when the 
Proposed Action can occur in the GOA Study Area based on weather 
conditions (April through October), time-of-day restrictions on the use 
of active sonar would prevent the Navy from successfully completing its 
mission requirements within the necessary timeframes. As described in 
Section 5.5.4 (Thermal Detection Systems and Unmanned Aerial Vehicles) 
of the 2022 GOA FSEIS/OEIS, thermal detection systems have not been 
sufficiently studied in terms of their effectiveness and compatibility 
with Navy military readiness activities. The Navy plans to continue 
researching thermal detection systems and will provide information to 
NMFS about the status and findings of Navy-funded thermal detection 
studies and any associated practicality assessments at the annual 
adaptive management meetings described in the Adaptive Management 
section of this rule. Please see NMFS' response to Comment 28 regarding 
passive acoustic monitoring.
    Comment 28: The Commission asserted that Navy lookouts have been 
determined to be ineffective, therefore passive and/or active acoustic 
monitoring must be used to supplement visual monitoring, especially for 
activities that could injure or kill marine mammals. The Commission 
recommended that NMFS require the Navy to use passive (i.e., DIFAR and 
other types of passive sonobuoys, operational hydrophones) and active 
acoustic (i.e., tactical sonars that are in use during the actual 
activity and active sonobuoys or other sources similar to fish-finding 
sonars) monitoring, whenever practicable, to supplement visual 
monitoring during the implementation of its mitigation measures for all 
activities that could cause injury or mortality. The Commission stated 
that at a minimum, sonobuoys deployed (e.g., see Binder et al. (2021)) 
and active sources and hydrophones used during an activity should be 
monitored for marine mammals--ideally, the Navy should develop and 
refine new technologies to supplement its visual monitoring, similar to 
the Department of National Defence in Canada (Binder et al., 2021, 
Thomson and Binder, 2021). The Commission stated that if NMFS does not 
adopt this recommendation, it recommends that NMFS justify (1) how it 
concluded that the Navy's mitigation measures based on visual 
monitoring do not need to be supplemented for those activities 
involving injury when Oedekoven and Thomas (2022) have determined that 
Navy lookouts are ineffective at sighting numerous types of marine 
mammals at various distances and for those activities involving 
mortality when marine mammals have been killed previously and (2) how 
visual monitoring is sufficient for effecting the least practicable 
adverse impact on the numerous marine mammal species and stocks.
    In a related comment, a commenter recommended installing passive 
acoustic monitoring in the TMAA to inform mariners about the presence 
of marine mammals.
    Response: While we acknowledge that the Lookout Effectiveness Study 
suggests that detection of marine mammals is less certain than 
previously assumed at certain distances, we disagree with the assertion 
that the Lookouts have been shown to be wholly ineffective. Lookouts 
remain an important component of the Navy's mitigation strategy, 
especially as it relates to minimizing exposure to the more harmful 
impacts that may occur within closer proximity to the source, where 
Lookouts are most effective. Further, as described below, NMFS and the 
Navy are also considering, through the adaptive management process, 
whether there are additional measures that would be practicable to 
implement that would improve effectiveness of Lookouts, such as 
enhanced personnel training.
    The Navy does employ passive acoustic devices (e.g., remote 
acoustic sensors, expendable sonobuoys, passive acoustic sensors on 
submarines) to supplement visual monitoring when practicable to do so 
(i.e., when assets that have passive acoustic monitoring capabilities 
are already participating in the activity) as discussed in Section 
5.2.1 (Procedural Mitigation Development) and Section 5.3 (Procedural 
Mitigation to be Implemented) of the 2022 GOA FSEIS/OEIS. We note that 
sonobuoys have a narrow band that does not overlap with the 
vocalizations of all marine mammals, and there is no bearing or 
distance on detections based on the number (e.g., one or two) and type 
of devices typically used; therefore it is not typically possible to 
use these to implement mitigation shutdown procedures. As discussed in 
Section 5.5.3 (Active and Passive Acoustic Monitoring Devices) of the 
2022 GOA FSEIS/OEIS, which NMFS reviewed and concurs accurately 
assesses the practicability of utilizing additional passive or active 
acoustic systems for mitigation monitoring, there are significant 
manpower and logistical constraints that make constructing and 
maintaining additional passive acoustic monitoring systems or platforms 
for each training and testing activity, or instrumented ranges, 
impracticable. The Navy's existing passive acoustic monitoring devices 
(e.g., sonobuoys) are designed, maintained, and allocated to specific 
training units or testing programs for specific mission-essential 
purposes. Reallocating these assets to different training units or 
testing programs for the purpose of monitoring for marine mammals would 
prevent the Navy from using its equipment for its intended mission-
essential purpose. Additionally, diverting platforms that have passive 
acoustic monitoring capability would impact their ability to meet their 
Title 10 requirements (see Section 1.4, Purpose of and Need for 
Proposed Military Readiness Training Activities, of the 2022 GOA FSEIS/
OEIS) and reduce the service life of those systems.

[[Page 625]]

    Furthermore, adding a passive acoustic monitoring capability to 
additional explosive activities (either by adding a passive acoustic 
monitoring device to a platform already participating in the activity, 
or by adding an additional platform to the activity) for mitigation is 
not practical. For example, all platforms participating in an explosive 
bombing exercise (e.g., firing aircraft, safety aircraft) must focus on 
situational awareness of the activity area and continuous coordination 
between multiple training components for safety and mission success. 
Therefore, it is impractical for participating platforms to divert 
their attention to non-mission essential tasks, such as deploying 
sonobuoys and monitoring for acoustic detections during the event 
(e.g., setting up a computer station). The Navy does not have available 
manpower or resources to allocate additional aircraft for the purpose 
of deploying, monitoring, and retrieving passive acoustic monitoring 
equipment during a bombing exercise.
    As noted in the comment, the Navy conducted a Lookout Effectiveness 
Study in association with the University of St. Andrews for several 
years to assess the ability of shipboard Lookouts to observe marine 
mammals while conducting hull-mounted sonar training activities at sea. 
The University of St. Andrews' report was provided to NMFS on April 1, 
2022 as required by a Term and Condition in the Endangered Species Act 
(ESA) Incidental Take Statements for the Biological Opinions associated 
with NMFS' 2020 final rule for Navy training and testing activities in 
the NWTT and Mariana Islands Training and Testing (MITT) Study Areas. 
The Lookout Effectiveness Study is available at https://www.navymarinespeciesmonitoring.us. Overall, the report provides NMFS 
and the Navy with valuable contextual information, but requires some 
level of interpretation with regard to the numerical results. For 
instance, the study's statistical model assumed that Navy ships moved 
in a straight line at a set speed for the duration of the field trials, 
and that animals could not move in a direction perpendicular to a ship. 
Violation of this model assumption would underestimate Lookout 
effectiveness for some data points. The Navy and NMFS determined that 
the Lookout Effectiveness Study results would not alter the acoustic 
effects quantitative analysis of potential impacts on marine mammals 
from the specified activities, and that the acoustic effects 
quantitative analyses included in the 2022 GOA FSEIS/OEIS and in the 
GOA proposed rule (87 FR 49656; August 11, 2022) did not underestimate 
the number or extent of marine mammal takes due to the conservative 
approach already taken by the Navy in its quantitative analysis 
process. NMFS and the Navy are currently working to determine how and 
to what extent the Study's results should be incorporated into future 
environmental analyses. The Navy and NMFS are also considering, through 
the adaptive management process, whether there are additional measures 
that would be practicable to implement that would improve effectiveness 
of Lookouts, such as enhanced personnel training.
    Regarding how NMFS concluded that the Navy's mitigation measures 
based on visual monitoring do not need to be supplemented for those 
activities involving injury considering Oedekoven and Thomas (2022), 
NMFS implemented the least practicable adverse impact standard as 
described in the Implementation of Least Practicable Adverse Impact 
Standard section of the proposed rule and in this final rule. As stated 
in the Take Request section of the proposed rule (87 FR 49656; August 
11, 2022) and the Take Estimation section of this final rule, for 
training activities in the GOA Study Area, no mortality or non-auditory 
injury is anticipated, even without consideration of planned mitigation 
measures. For the reasons described above in this response, including 
cost, impact on the specified activities, practicality of 
implementation, and impact on the effectiveness of the military 
readiness activity, the Commission's recommendations are not 
practicable. Therefore, absent additional available techniques for 
mitigation monitoring, the procedural mitigation and mitigation areas 
described in this final rule are sufficient for effecting the least 
practicable adverse impact on the numerous marine mammal species and 
stocks.

Other Comments

    Comment 29: The Commission noted that the Navy recently published 
the 2022 GOA FSEIS/OEIS for conducting the proposed training activities 
in GOA (87 FR 54214; September 2, 2022) and requested any comments by 
October 3, 2022. The public comment period for NMFS' proposed rule 
closed September 26, 2022 (87 FR 49656; August 11, 2022). The 
Commission stated it is unclear whether and how any changes to the 
proposed rule would inform the 2022 GOA FSEIS/OEIS, as it has already 
been drafted and determinations apparently already made. Under the 
Administrative Procedure Act (APA), an agency is expected to provide a 
full and sufficient rationale supporting its action at the time any 
statutory decision is made. That rationale is comprised in part by the 
agency's responses to public comments, which in this case were included 
in Appendix G81 of the 2022 GOA FSEIS/OEIS. Since NMFS was a 
cooperating agency on the 2020 GOA DSEIS/OEIS and indicated that it 
plans to adopt the FSEIS that will underpin the final rule (87 FR 
49757; August 11, 2022), it can be perceived as though decisions have 
been made preemptively for the various statutory determinations. Such 
practice runs counter to the requirements of the APA and undermines the 
intent of the public process.
    Response: This rulemaking process provided notice and opportunity 
for the pubic to comment prior to final decision-making by NMFS on both 
the 2022 GOA FSEIS/OEIS and this MMPA rule. In the proposed rule (87 FR 
49656; August 11, 2022), NMFS stated its plan to adopt the GOA SEIS/
OEIS for the GOA Study Area provided our independent evaluation of the 
document found that it included adequate information analyzing the 
effects on the human environment of issuing regulations and an LOA 
under the MMPA. We further stated in the proposed rule that we would 
review all comments prior to concluding our National Environmental 
Policy Act (NEPA) process and making a final decision on the MMPA 
rulemaking and request for a LOA, which we have since done.
    Neither NMFS nor the Navy signed a Record of Decision (the decision 
document through which NMFS adopted the 2022 GOA FSEIS/OEIS) until the 
comments received in both the NEPA and MMPA processes were considered. 
During this rulemaking process, had comments been received on the 
proposed rule that warranted changes or additional analysis in the NEPA 
process, NMFS and the Navy would have addressed these comments through 
each agency's Record of Decision, or otherwise amended the analysis to 
address the issues raised by any such comments.
    Comment 30: A commenter stated that NMFS should consult with Alaska 
Native communities and add mitigation for environmental justice 
impacts.
    Response: NMFS invited Alaska Native federally-recognized Tribes in 
the Gulf of Alaska region to a presentation and opportunity to discuss 
the proposed rule. A member from one Tribe attended, and indicated that 
the Tribe would likely submit a letter with recommendations for 
consideration in

[[Page 626]]

the final rule. Further, the Navy has consulted and will continue to 
consult with Alaska Native Tribes through government-to-government 
consultations (see Appendix E (Agency Correspondence) of the 2022 GOA 
FSEIS/OEIS). One Tribe provided recommendations to the Navy as part of 
the GOA FSEIS/OEIS process, which NMFS reviewed and considered in 
preparing its proposed rule (87 FR 49656; August 11, 2022).
    It is unclear what the commenter means by ``add mitigation for 
environmental justice impacts,'' and the commenter did not provide 
sufficient information in order to incorporate such a recommendation. 
However, the Portlock Bank Mitigation Area that was included in the 
2020 Draft SEIS/OEIS was developed for the purpose of reducing 
potential impacts on fishery resources in a location important to 
Alaska Native Tribes. That mitigation area was expanded, as included in 
NMFS' proposed rule (87 FR 49656; August 11, 2022), this final rule, 
and in the 2022 GOA FSEIS/OEIS, to cover the entire continental shelf 
and slope in a new area called the Continental Shelf and Slope 
Mitigation Area. (Please see the Mitigation Areas section of this final 
rule and Section 5.4 (Geographic Mitigation to be Implemented) of the 
2022 GOA FSEIS/OEIS for additional details about the requirements in 
this area and the ecological benefits.)
    The MMPA requires that ITAs must not have an unmitigable adverse 
impact on subsistence uses (16 U.S.C. 1371(a)(5)(A)(i)), and NMFS has 
determined that the total taking of affected species or stocks will not 
have an unmitigable adverse impact on the availability of the species 
or stocks for taking for subsistence purposes. The Navy's training 
activities are not expected to impact the ability of Alaska Natives to 
conduct subsistence hunts or the availability of marine mammals to 
those hunts. There is no spatial and temporal overlap between the 
Navy's proposed activities and subsistence whaling or sealing areas. 
The GOA Study Area is located over 12 nautical miles offshore with the 
nearest inhabited land being the Kenai Peninsula (24 nautical miles 
from the GOA Study Area). Information provided by Tribes in harvest 
reports indicates that harvests tend to occur nearshore, and they do 
not use the GOA Study Area for subsistence hunting of marine mammals. 
Please see the Subsistence Harvest of Marine Mammals section for more 
information.
    Comment 31: A commenter stated that NMFS should deny the proposed 
LOA application because there are already several active LOAs in Alaska 
that allow the take of many of the same species as requested by the 
proposed LOA, and that the cumulative impacts of the proposed LOA 
combined with the active LOAs demonstrates that the proposed LOA will 
have a non-negligible impact on the impacted species or stocks. The 
commenter references the following authorizations and the number of 
authorized takes of marine mammals for each project: USGS Floating Dock 
Expansion; Hoonah Marine Industrial Center Cargo Dock; Alaska 
Department of Transportation and Public Facilities Ferry Berth 
Improvements; NOAA Port Facility Project in Ketchikan, AK; Reissuance 
of Alaska Department of Transportation and Public Facilities Metlakatla 
Facility; Hilcorp Alaska, LLC Oil and Gas; AGDC Liquefied Natural Gas 
Construction; NOAA Fisheries Research in the Arctic Ocean (see Friends 
of Animals' comment letter for additional detail). Further, the 
commenter stated that the actual total number of takes for these 
projects is even greater than the number included in these 
authorizations because these projects do not include all the active 
authorizations or the authorizations currently in progress in Alaska. 
The commenter stated that when considering the projects cumulatively, 
there is a large number of authorizations authorizing the take of vast 
numbers of marine mammals in Alaska.
    Response: The MMPA requires that NMFS issue an incidental take 
authorization, provided the necessary findings are made for the 
specified activity put forth in the application and appropriate 
mitigation and monitoring measures are set forth, as described in the 
Background section of this notice. Both the statute and the agency's 
implementing regulations call for analysis of the effects of the 
applicant's activities on the affected species and stocks, not analysis 
of other unrelated activities and their impacts on the species and 
stocks. That does not mean, however, that effects on the species and 
stocks caused by other activities are ignored. As described in the GOA 
Study Area proposed rule (87 FR 49656; August 11, 2022) and this final 
rule, the preamble for NMFS' implementing regulations under section 
101(a)(5) (54 FR 40338; September 29, 1989) explains in response to 
comments that the impacts from other past and ongoing anthropogenic 
activities are incorporated into the negligible impact analysis via 
their impacts on the environmental baseline. Consistent with that 
direction, NMFS has factored into its negligible impact analyses the 
impacts of other past and ongoing anthropogenic activities via their 
impacts on the baseline (e.g., as reflected in the density/distribution 
and status of the species, population size and growth rate, and other 
relevant stressors (such as Unusual Mortality Events (UMEs)). See the 
Analysis and Negligible Impact Determination section of this rule.
    Our 1989 final rule for the MMPA implementing regulations also 
addressed how cumulative effects from unrelated activities would be 
considered. There we stated that such effects are not separately 
considered in making findings under section 101(a)(5) concerning 
negligible impact, but that NMFS would consider cumulative effects that 
are reasonably foreseeable when preparing a NEPA analysis and also that 
reasonably foreseeable cumulative effects would be considered under 
section 7 of the ESA for ESA-listed species.
    The cumulative effects of the incremental impact of the proposed 
action when added to other past, present, and reasonably foreseeable 
future actions (as well as the effects of climate change) were 
evaluated against the appropriate resources and regulatory baselines in 
the 2022 GOA FSEIS/OIES. The best available science and a comprehensive 
review of past, present, and reasonably foreseeable actions (including 
construction and oil and gas activities) was used to develop the 
Cumulative Impacts analysis. This analysis is contained in Chapter 4 of 
the 2022 GOA FSEIS/OIES. As required under NEPA, the level and scope of 
the analysis is commensurate with the scope of potential impacts of the 
action and the extent and character of the potentially-impacted 
resources (e.g., the geographic boundaries for cumulative impacts 
analysis for some resources are expanded to include activities outside 
the GOA Study Area that might impact migratory or wide-ranging 
animals), as reflected in the resource-specific discussions in Chapter 
3 (Affected Environment and Environmental Consequences) of the 2022 GOA 
FSEIS/OEIS. The 2022 GOA FSEIS/OEIS considered the proposed training 
activities alongside other actions in the region whose impacts may be 
additive to those of the proposed training. Past and present actions 
are also included in the analytical process as part of the affected 
environmental baseline conditions presented in Chapter 3 of the 2022 
GOA FSEIS/OEIS. The 2022 GOA FSEIS/OEIS did so in accordance with 1997 
Council on Environmental Quality (CEQ) guidance. Per the guidance, a 
qualitative approach and best

[[Page 627]]

professional judgment are appropriate where precise measurements are 
not available. Where precise measurements and/or methodologies were 
available, they were used. Guidance from CEQ states it ``is not 
practical to analyze cumulative effects of an action on the universe; 
the list of environmental effects must focus on those that are truly 
meaningful.''
    Further, cumulative effects to listed species of the specified 
activity in combination with other activities are analyzed in the ESA 
biological opinion. This analysis is contained in section 9 (Cumulative 
Effects). The opinion states that it assumes effects in the future 
would be similar to those in the past and, therefore, are reflected in 
the anticipated trends described in the Species and Designated Critical 
that May be Affected and Environmental Baseline sections of the 
biological opinion (Sections 0 and 7, respectively).
    Comment 32: The Commission recommended that NMFS (1) specify the 
total numbers of model-estimated Level A harassment (PTS) takes in the 
preamble to the final rule and (2) authorize the model-estimated Level 
A harassment takes in the final rule, ensuring that those takes inform 
the negligible impact determination analyses. If NMFS does not adopt 
the Commission's recommendation, then the Commission recommended that 
in the preamble to the final rule NMFS (1) provide details on the 
specific mitigation effectiveness scores and how the model-estimated 
Level A harassment takes were reduced based on avoidance and the 
mitigation effectiveness scores and (2) justify how it can continue to 
allow the Navy to implement mitigation effectiveness scores to reduce 
Level A harassment takes when Navy lookouts have been determined to be 
ineffective at sighting marine mammals. At the very least, the 
estimated mitigation effectiveness scores from Oedekoven and Thomas 
(2022) should have been used to reduce any Level A harassment takes 
that were estimated to occur within 914 m of a surface vessel operating 
MFA or high-frequency active (HFA) sonar rather than arbitrary, 
presumed mitigation effectiveness scores that are not supported by best 
available science. Reducing model-estimated takes based on mitigation 
effectiveness for other activities remains unsubstantiated. As such, 
mitigation effectiveness should not be used to reduce the numbers of 
marine mammal takes for the final rule for GOA or any of the upcoming 
Phase IV rulemakings.
    Response: The consideration of marine mammal avoidance and 
mitigation effectiveness is an important part of NMFS' and the Navy's 
overall analysis of impacts from sonar and explosive sources. NMFS has 
independently evaluated the method and agrees that it is appropriately 
applied to augment the model in the prediction and authorization of 
injury and mortality as described in the rule, including after 
consideration of Oedekoven and Thomas (2022). Details of the analysis 
are provided in the Navy's 2018 technical report titled ``Quantifying 
Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and 
Analytical Approach for Phase III Training and Testing.'' Detailed 
information on the mitigation analysis was included in the proposed 
rule, including information about the technical report.
    As discussed in the proposed rule, this final rule, and the Navy's 
report, animats in the Navy's acoustic effects model do not move 
horizontally or ``react'' to sound in any way. Specifically, this means 
that the Navy's model does not take into account either the likelihood 
of avoidance or any consideration of mitigation effectiveness. 
Accordingly, NMFS and the Navy's analysis appropriately applies a 
quantitative adjustment to the exposure results calculated by the model 
to consider avoidance and mitigation.
    Regarding avoidance, sound levels diminish quickly below levels 
that could cause PTS. Specifically, behavioral response literature, 
including the recent 3S studies (multiple controlled sonar exposure 
experiments on cetaceans in Norwegian waters) and Southern California 
behavioral response studies (SOCAL BRS) (multiple cetacean behavioral 
response studies in Southern California), indicate that multiple 
species from different cetacean suborders do in fact avoid approaching 
sound sources by a few hundred meters or more, which would reduce 
received sound levels for individual marine mammals to levels below 
those that could cause PTS (see Appendix B of the ``Criteria and 
Thresholds for U.S. Navy Acoustic and Explosive Impacts to Marine 
Mammals and Sea Turtles Technical Report'' (U.S. Department of the 
Navy, 2017) and Southall et al. (2019a)). The ranges to PTS for most 
marine mammal groups are within a few tens of meters and the ranges for 
the most sensitive group, the HF cetaceans, average about 200 m, to a 
maximum of 270 m in limited cases. HF cetaceans such as harbor 
porpoises, however, have been observed reacting to anthropogenic sound 
at greater distances than other species and are likely to avoid their 
zones of hearing impacts (TTS and PTS) as well. Section 3.8.3.1.1.5 
(Behavioral Reactions--Behavioral Reactions to Sonar and Other 
Transducers) in Section 3.8 (Marine Mammals) of the 2022 GOA FSEIS/OEIS 
documents multiple studies in which marine mammals responded to sonar 
exposure with avoidance at exposures below which PTS would occur.
    As discussed in the Navy's report, the Navy's acoustic effects 
model does not consider procedural mitigations (i.e., power-down or 
shut-down of sonars, or pausing explosive activities when animals are 
detected in specific zones adjacent to the source), which necessitates 
consideration of these factors in the Navy's overall acoustic analysis. 
Credit taken for mitigation effectiveness is extremely conservative. 
For example, if Lookouts can see the whole area, they get credit for it 
in the calculation; if they can see more than half the area, they get 
half credit; if they can see less than half the area, they get no 
credit. Not considering animal avoidance and mitigation effectiveness 
would lead to a great overestimate of injurious impacts and not 
constitute the best available scientific information. NMFS concurs with 
the analytical approach used, i.e., we believe the estimated take by 
Level A harassment numbers represent the maximum number of these takes 
that are likely to occur and it would not be appropriate to authorize a 
higher number or consider a higher number in the negligible impact 
analysis.
    The Navy assumes that Lookouts will not be 100 percent effective at 
detecting all individual marine mammals within the mitigation zones for 
each activity. This is due to the inherent limitations of observing 
marine species and because the likelihood of sighting individual 
animals is largely dependent on observation conditions (e.g., time of 
day, sea state, mitigation zone size, observation platform) and animal 
behavior (e.g., the amount of time an animal spends at the surface of 
the water). The Navy quantitatively assessed the effectiveness of its 
mitigation measures on a per-scenario basis for four factors: (1) 
species sightability, (2) a Lookout's ability to observe the range to 
permanent threshold shift (for sonar and other transducers) and range 
to mortality (for explosives), (3) the portion of time when mitigation 
could potentially be conducted during periods of reduced daytime 
visibility (to include inclement weather and high sea-state) and the 
portion of time when mitigation could potentially be conducted at 
night, and (4) the ability for sound sources to be

[[Page 628]]

positively controlled (e.g., powered down).
    The adjustment made for mitigation effectiveness is small (no more 
than \1/3\ of the takes by PTS adjusted) to ensure that takes by PTS 
are not underestimated. The Navy's models predicted take by PTS for fin 
whale, Dall's porpoise, and northern elephant seal only. Takes by PTS 
from explosives were not adjusted to account for avoidance or 
mitigation for any species (i.e., the authorized take by PTS from 
explosives is equal to the model-estimated PTS from explosives). For 
fin whale, Navy Acoustic Effects Model (NAEMO) predicted 1.6 takes by 
PTS from sonar, which was reduced to 0 after consideration of both 
mitigation credit (-0.5 takes by PTS) and avoidance (-1.05 takes by 
PTS). For Dall's porpoise, NAEMO predicted 527 takes by PTS from sonar, 
which was reduced to 19 after consideration of both mitigation credit 
(-144 takes by PTS) and avoidance (-364 takes by PTS). (Given that the 
calculation for avoidance incorporates the adjustment made for 
mitigation effectiveness, for Dall's porpoise, even if no adjustment 
were made for mitigation effectiveness, the overall number of takes by 
PTS (from sonar and explosives) would increase by just 7 takes.) For 
elephant seal, NAEMO predicted 0 takes by PTS from sonar, and 
therefore, no adjustment was made for mitigation or avoidance.
    The g(0) values used by the Navy for their mitigation effectiveness 
adjustments take into account the differences in sightability with sea 
state, and utilize averaged g(0) values for sea states of 1-4 and 
weighted as suggested by Barlow (2015). Using g(0) values is an 
appropriate and conservative approach (i.e., it underestimates the 
protection afforded by the Navy's mitigation measures) for the reasons 
detailed in the technical report. For example, during line-transect 
surveys, there are typically two primary observers searching for 
animals. Each primary observer looks for marine species in the forward 
90-degree quadrant on their side of the survey platform and scans the 
water from the vessel out to the limit of the available optics (i.e., 
the horizon). Because Navy Lookouts focus their observations on 
established mitigation zones, their area of observation is typically 
much smaller than that observed during line-transect surveys. The 
mitigation zone size and distance to the observation platform varies by 
Navy activity. For example, during hull-mounted mid-frequency active 
sonar activities, the mitigation zone extends 1,000 yd from the ship 
hull. During the conduct of training 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 for and disseminate 
marine species sighting information amongst the units participating in 
the activity whenever possible as they conduct their primary mission 
responsibilities. However, as a conservative approach to assigning 
mitigation effectiveness factors, the Navy elected to account only for 
the minimum number of required Lookouts used for each activity; 
therefore, the mitigation effectiveness factors may underestimate the 
likelihood that some marine mammals may be detected during activities 
that are supported by additional personnel who may also be observing 
the mitigation zone, even considering the mitigation scores reported in 
Oedekoven and Thomas (2022).
    While use of the estimated mitigation effectiveness scores from 
Oedekoven and Thomas (2022) to reduce Level A harassment takes may be 
more conservative than the current scores, using the Oedekoven and 
Thomas (2022) scores would not necessarily be more accurate, given the 
assumptions made in the report. For small cetaceans in particular, as 
stated in the report, ``the [Oedekoven and Thomas (2022)] model assumed 
no horizontal movement, while some small cetaceans are attracted to 
ships and can move quickly'' or show avoidance behaviors, though, the 
report does note that despite that limitation, the probability of small 
cetaceans going undetected is still high. The Navy's mitigation 
effectiveness adjustments also assume a high probability that an animal 
would go undetected.
    In addition to the differences in assumptions highlighted above, 
the p(detection) in the Oedekoven and Thomas (2022) takes into account 
the portion of time an animal or pod is at the surface. For 
availability, Oedekoven and Thomas (2022) used assumptions about dive 
behavior based on several representative species (the most sighted 
species in the study) and applied these assumptions across entire 
animal groups (rorqual, sperm, and small cetacean). Alternatively, the 
Navy's analysis uses specific g(0) values for the species in the study 
area. Given the differences in assumptions between the Navy's methods 
and those outlined in Oedekoven and Thomas (2022), NMFS does not find 
it appropriate to modify the mitigation effectiveness adjustment based 
on the Oedekoven and Thomas (2022) results at this time. However, NMFS 
and the Navy are continuing to evaluate the report results in order to 
determine how to best apply mitigation effectiveness moving forward.
    Although NAEMO predicted PTS takes from the GOA activities, no 
mortality or non-auditory injuries were predicted by NAEMO. Therefore, 
as detailed in the Estimated Take of Marine Mammals section of this 
rule, and in Section 3.8.3.2.2.1 (Methods for Analyzing Impacts from 
Explosives) of the 2022 GOA FSEIS/OEIS, the Navy Acoustic Effects Model 
estimated zero takes by mortality for all marine mammal species in the 
TMAA. Therefore, mitigation for explosives is discussed qualitatively 
but was not factored into the quantitative analysis for marine mammals 
(i.e., mitigation effectiveness scores were not calculated, or used to 
reduce mortality exposures for explosives). For all of the reasons 
above, NMFS considers the estimated and authorized take (that was 
adjusted for aversion and mitigation) appropriate, and that is what has 
been analyzed in the negligible impact analysis. Accordingly, we 
decline the commenter's recommendation to analyze and authorize the 
model-estimated PTS, as it is neither expected to occur nor authorized.
    Comment 33: A commenter stated that the Navy could use modern 
technology in simulators for its training exercises, and that it could 
use computer simulation and other technological techniques to better 
train their personnel.
    Response: As described in Section 2.5.5 (Simulated Training) in the 
2022 GOA Final SEIS/OEIS, the Navy continues to use computer simulation 
and other types of simulation for training activities whenever 
possible; however, there are limits to the realism that current 
simulation technology can provide, and its use cannot substitute for 
live training. Training through simulated means cannot replicate the 
conditions in which Navy personnel and platforms are required to 
conduct military operations. While beneficial as a complementing medium 
to train and test personnel and platforms, simulation alone cannot 
accurately replicate both the conditions and the stresses that must be 
placed on personnel and platforms during actual training. These 
conditions and stresses are absolutely vital to adequately preparing 
Naval forces to conduct the broad spectrum of military operations 
required of them by operational Commanders. Therefore, simulation as an 
alternative that

[[Page 629]]

completely replaces training in the field does not meet the purpose of 
and need for the Navy's proposed action and was eliminated from further 
analysis.
    The commenter did not provide sufficient information regarding 
``other technological techniques to better training their personnel'' 
in order to incorporate such a recommendation.
    Comment 34: A commenter stated that the Navy should not increase 
the amount of incidental take of marine mammals in their quest to 
expand the size of the training zone in the Gulf of Alaska Study Area. 
The commenter stated that the Navy could better utilize the existing 
zone at its current size, and that the testing of real weapons should 
only occur within the existing training zone. Further, when exercises 
occur, utmost caution should be exercised in the whereabouts of marine 
mammals.
    Response: The inclusion of the WMA in the GOA Study Area is not 
expected to result in additional take of marine mammals beyond that 
which will occur in the TMAA portion of the GOA Study Area. As stated 
in the proposed rule (87 FR 49656; August 11, 2022), no activities 
involving sonar use or explosives will occur in the WMA or the portion 
of the warning area that extends beyond the TMAA. The WMA provides 
additional airspace and sea space for aircraft and vessels to maneuver 
during training activities for increased training complexity.
    Regarding caution around marine mammals, the Navy is required to 
implement mitigation measures, including procedural mitigation 
measures, such as required shutdowns and delays of activities if marine 
mammals are sighted within certain distances, and geographic area 
mitigation measures, including limitations on activities such as sonar 
in areas that are important for certain behaviors such as feeding. 
These mitigation measures were designed to lessen the frequency and 
severity of impacts from the Navy's activities on marine mammals and 
their habitat, and ensure that the Navy's activities have the least 
practicable adverse impact on species and stocks. See the Mitigation 
Measures section of this final rule for additional detail on specific 
procedural mitigation measures and measures in mitigation areas.

Changes From the Proposed Rule to the Final Rule

    This final rule includes no substantive changes from the proposed 
rule. However, this final rule includes a minor addition to reporting 
requirements. The new measure requires the Navy to coordinate with NMFS 
prior to conducting exercises within the GOA Study Area. This may occur 
as a part of coordination the Navy does with other local stakeholders.

Description of Marine Mammals and Their Habitat in the Area of the 
Specified Activities

    Marine mammal species and their associated stocks that have the 
potential to occur in the GOA Study Area are presented in Table 6. The 
Navy anticipates the take of individuals of 16 marine mammal species by 
Level A harassment and Level B harassment, and NMFS has conservatively 
analyzed and authorized incidental take of two additional species. The 
Navy does not request authorization for any serious injuries or 
mortalities of marine mammals, and NMFS agrees that serious injury and 
mortality is unlikely to occur from the Navy's activities. NMFS 
recently designated critical habitat under the Endangered Species Act 
(ESA) for humpback whales in the TMAA portion of the GOA Study Area, 
and this designated critical habitat is considered below (86 FR 21082; 
April 21, 2021). The WMA portion of the GOA Study Area does not overlap 
ESA-designated critical habitat for humpback whales or any other 
species.
    The GOA proposed rule included additional information about the 
species in this rule, all of which remains valid and applicable but has 
not been reprinted in this final rule, including a subsection entitled 
Marine Mammal Hearing that described the importance of sound to marine 
mammals and characterized the different groups of marine mammals based 
on their hearing sensitivity. Therefore, we refer the reader to our 
Federal Register notice of proposed rulemaking (87 FR 49656; August 11, 
2022) for more information.
    Information on the status, distribution, abundance, population 
trends, habitat, and ecology of marine mammals in the GOA Study Area 
may be found in Chapter 4 of the Navy's rulemaking/LOA application. 
NMFS reviewed this information and found it to be accurate and 
complete. Additional information on the general biology and ecology of 
marine mammals is included in the 2022 GOA FSEIS/OEIS. Table 6 
incorporates the best available science, including data from the 2021 
U.S. Pacific and the Alaska Marine Mammal Stock Assessment Reports 
(SARs; Carretta et al., 2022; Muto et al., 2022), as well as monitoring 
data from the Navy's marine mammal research efforts. NMFS has also 
reviewed new scientific literature since publication of the proposed 
rule and determined that none of these nor any other new information 
changes our determination of which species have the potential to be 
affected by the Navy's activities or the information pertinent to 
status, distribution, abundance, population trends, habitat, or ecology 
of the species in this final rulemaking, except as noted below.
    To better define marine mammal occurrence in the TMAA, the portion 
of the GOA Study Area where take of marine mammals is anticipated to 
occur, four regions within the TMAA were defined (and are depicted in 
Figure 3-1 of the Navy's rulemaking/LOA application), consistent with 
the survey strata used by Rone et al. (2017) during the most recent 
marine mammal surveys in the TMAA. The four regions are: inshore, 
slope, seamount, and offshore.

                                               Table 6--Marine Mammal Occurrence Within the GOA Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                              Stock abundance
                                                                              ESA status,   (CV, Nmin, year of
           Common name              Scientific name           Stock          MMPA status,       most recent        PBR     Annual M/   Occurrence in GOA
                                                                             strategic (Y/   abundance survey)               SI \3\     study area \4\
                                                                                N) \1\              \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Order Artiodactyla
                                                                   Infraorder Cetacea
                                                                Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae (right
 whales):
    North Pacific right whale...  Eubalaena japonica.  Eastern North        E, D, Y         31 (0.226, 26,       \5\ 0.05          0  Rare.
                                                        Pacific.                             2008).

[[Page 630]]

 
Family Balaenopteridae
 (rorquals):
    Humpback whale..............  Megaptera            Central North        -, -, Y         10,103 (0.3,               83         26  Seasonal; highest
                                   novaeangliae.        Pacific \6\.                         7,891, 2006).                             likelihood June
                                                                                                                                       to September.
                                                       California, Oregon,  -, -, Y         4,973 (0.05,             28.7     >=48.3  Seasonal; highest
                                                        and Washington \6\.                  4,776, 2018).                             likelihood June
                                                                                                                                       to September.
                                                       Western North        E, D, Y         1,107 (0.3, 865,            3        2.8  Seasonal; highest
                                                        Pacific.                             2006).                                    likelihood June
                                                                                                                                       to September.
    Blue whale..................  Balaenoptera         Eastern North        E, D, Y         1,898 (0.085,             4.1     >=19.5  Seasonal; highest
                                   musculus.            Pacific.                             1,767, 2018).                             likelihood June
                                                                                                                                       to December.
                                                       Central North        E, D, Y         133 (1.09, 63,            0.1          0  Seasonal; highest
                                                        Pacific.                             2010).                                    likelihood June
                                                                                                                                       to December.
    Fin whale...................  Balaenoptera         Northeast Pacific..  E, D, Y         3,168 (0.26,              5.1        0.6  Likely.
                                   physalus.                                                 2,554, 2013) \7\.
    Sei whale...................  Balaenoptera         Eastern North        E, D, Y         519 (0.4, 374,           0.75      >=0.2  Rare.
                                   borealis.            Pacific \8\.                         2014).
    Minke whale.................  Balaenoptera         Alaska.............  -, -, N         UNK...............        UND          0  Likely.
                                   acutorostrata.
Family Eschrichtiidae (gray
 whale):
    Gray whale..................  Eschrichtius         Eastern North        -, -, N         26,960 (0.05,             801        131  Likely: Highest
                                   robustus.            Pacific.                             25,849, 2016).                            numbers during
                                                                                                                                       seasonal
                                                                                                                                       migrations (fall,
                                                                                                                                       winter, spring).
                                                       Western North        E, D, Y         290 (N/A, 271,           0.12        UNK  Rare: Individuals
                                                        Pacific.                             2016).                                    migrate through
                                                                                                                                       GOA.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Odontoceti (toothed whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae (sperm
 whale):
    Sperm whale.................  Physeter             North Pacific......  E, D, Y         345 (0.43, 244,           UND        3.5  Likely; More
                                   macrocephalus.                                            2015) \9\.                                likely in waters
                                                                                                                                       >1,000 m depth,
                                                                                                                                       most often >2,000
                                                                                                                                       m.
Family Delphinidae (dolphins):
    Killer whale................  Orcinus orca.......  Eastern North        -, -, N         2,347 \10\ (N/A,           24          1  Likely.
                                                        Pacific Alaska                       2,347, 2012).
                                                        Resident.
                                                       Eastern North        -, -, N         300 (0.1, 276,            2.8          0  Likely.
                                                        Pacific Offshore.                    2012).
                                                       AT1 Transient......  -, D, Y         7 \10\ (N/A, 7,          0.01          0  Rare; more likely
                                                                                             2019).                                    inside Prince
                                                                                                                                       William Sound and
                                                                                                                                       Kenai Fjords.
                                                       Eastern North        -, -, N         587 \10\ (N/A,            5.9        0.8  Likely.
                                                        Pacific GOA,                         587, 2012).
                                                        Aleutian Island,
                                                        and Bering Sea
                                                        Transient.
    Pacific white-sided dolphin.  Lagenorhynchus       North Pacific......  -, -, N         26,880 (N/A, N/A,         UND          0  Likely.
                                   obliquidens.                                              1990).
Family Phocoenidae (porpoises):
    Harbor porpoise.............  Phocoena phocoena..  GOA................  -, -, Y         31,046 (0.21, N/A,        UND         72  Rare; Inshore and
                                                                                             1998).                                    Slope Regions, if
                                                                                                                                       present.
                                                       Southeast Alaska...  -, -, Y         1,302 (0.21,               11         34  Rare.
                                                                                             1,057, 2019).
    Dall's porpoise.............  Phocoenoides dalli.  Alaska.............  -, -, N         83,400 (0.097,            131         37  Likely.
                                                                                             13,110, 2015).
Family Ziphiidae (beaked
 whales):
    Cuvier's beaked whale.......  Ziphius cavirostris  Alaska.............  -, -, N         UNK...............        UND          0  Likely.
    Baird's beaked whale........  Berardius bairdii..  Alaska.............  -, -, N         UNK...............        UND          0  Likely.
    Stejneger's beaked whale....  Mesoplodon           Alaska.............  -, -, N         UNK...............        UND          0  Likely.
                                   stejnegeri.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Order Carnivora
                                                                       Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otarieidae (fur seals and
 sea lions):

[[Page 631]]

 
    Steller sea lion............  Eumetopias jubatus.  Eastern U.S........  -, -, N         43,201 \11\ (N/A,       2,592        112  Rare.
                                                                                             43,201, 2017).
                                                       Western U.S........  E, D, Y         52,932 \11\ (N/A,         318        254  Likely; Inshore
                                                                                             52,932, 2019).                            region.
    California sea lion.........  Zalophus             U.S................  -, -, N         257,606 (N/A,          14,011       >321  Rare (highest
                                   californianus.                                            233,515, 2014).                           likelihood April
                                                                                                                                       and May).
    Northern fur seal...........  Callorhinus ursinus  Eastern Pacific....  -, D, Y         626,618 (0.2,          11,403        373  Likely.
                                                                                             530,376, 2019).
                                                       California.........  -, -, N         14,050 (N/A,              451        1.8  Rare.
                                                                                             7,524, 2013).
Family Phocidae (true seals):
    Northern elephant seal......  Mirounga             California Breeding  -, -, N         187,386 (N/A,           5,122       13.7  Seasonal (highest
                                   angustirostris.                                           85,369, 2013).                            likelihood July-
                                                                                                                                       September).
Harbor seal.....................  Phoca vitulina.....  N Kodiak...........  -, -, N         8,677 (N/A, 7,609,        228         38  Likely; Inshore
                                                                                             2017).                                    region.
                                                       S Kodiak...........  -, -, N         26,448 (N/A,              939        127  Likely; Inshore
                                                                                             22,351, 2017).                            region.
                                                       Prince William       -, -, N         44,756 (N/A,            1,253        413  Likely; Inshore
                                                        Sound.                               41,776, 2015).                            region.
                                                       Cook Inlet/Shelikof  -, -, N         28,411 (N/A,              807        107  Likely; Inshore
                                                                                             26,907, 2018).                            region.
    Ribbon seal.................  Histriophoca         Unidentified.......  -, -, N         184,697 (N/A,           9,785        163  Rare.
                                   fasciata.                                                 163,086, 2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: CV = coefficient of variation, ESA = Endangered Species Act, GOA = Gulf of Alaska, m = meter(s), MMPA = Marine Mammal Protection Act, N/A = not
  available, U.S. = United States, M/SI = mortality and serious injury, UNK = unknown, UND = undetermined.
\1\ 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 potential biological removal (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.
\2\ The stocks and stock abundance number are as provided in Carretta et al., 2022 and Muto et al., 2022. Nmin is the minimum estimate of stock
  abundance. In some cases, CV is not applicable. NMFS marine mammal stock assessment reports online at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region.
\3\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality and serious injury (M/SI) from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual mortality and serious injury (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.
\4\ RARE: The distribution of the species is near enough to the GOA Study Area that the species could occur there, or there are a few confirmed
  sightings. LIKELY: Year-round sightings or acoustic detections of the species in the GOA Study Area, although there may be variation in local
  abundance over the year. SEASONAL: Species absence and presence as documented by surveys or acoustic monitoring. Regions within the GOA Study Area
  follow those presented in Rone et al. (2015); Rone et al. (2009); Rone et al. (2014); Rone et al. (2017): inshore, slope, seamount, and offshore.
\5\ See SAR for more details.
\6\ Humpback whales in the Central North Pacific stock and the California, Oregon, and Washington stock are from three DPSs based on animals identified
  in breeding areas in Hawaii, Mexico, and Central America (Carretta et al., 2022; Muto et al., 2022; National Marine Fisheries Service, 2016c).
\7\ The SAR reports this stock abundance assessment as provisional and notes that it is an underestimate for the entire stock because it is based on
  surveys which covered only a small portion of the stock's range.
\8\ This analysis assumes that these individuals are from the Eastern North Pacific stock.
\9\ The SAR reports that this is an underestimate for the entire stock because it is based on surveys of a small portion of the stock's extensive range
  and it does not account for animals missed on the trackline or for females and juveniles in tropical and subtropical waters.
\10\ Stock abundance is based on counts of individual animals identified from photo-identification catalogs. Surveys for abundance estimates of these
  stocks are conducted infrequently.
\11\ Stock abundance is the best estimate of pup and non-pup counts, which have not been corrected to account for animals at sea during abundance
  surveys.

    Below, we include 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

    On April 21, 2021 (86 FR 21082), NMFS published a final rule 
designating critical habitat for the endangered Western North Pacific 
DPS, the endangered Central America DPS, and the threatened Mexico DPS 
of humpback whales, including specific marine areas located off the 
coasts of California, Oregon, Washington, and Alaska. Based on 
consideration of national security, economic impacts, and data 
deficiency in some areas, NMFS excluded certain areas from the 
designation for each DPS.
    NMFS identified prey species, primarily euphausiids and small 
pelagic schooling fishes (see the final rule for particular prey 
species identified for each DPS; 86 FR 21082; April 21, 2021) of 
sufficient quality, abundance, and accessibility within humpback whale 
feeding areas to support feeding and population growth, as an essential 
habitat feature. NMFS, through a critical habitat review team (CHRT), 
also considered inclusion of migratory corridors and passage features, 
as well as sound and the soundscape, as essential habitat features. 
However, NMFS did not include either, as the CHRT concluded that the 
best available science did not allow for identification of any 
consistently used migratory corridors or definition of any physical, 
essential migratory or passage conditions for whales transiting between 
or within habitats of the three DPSs. The best available science also 
currently does not enable NMFS to identify a sound-related habitat 
feature that is essential to the conservation of humpback whales.
    NMFS considered the co-occurrence of this designated humpback whale 
critical habitat and the GOA Study Area. Figure 4-1 of the Navy's 
rulemaking/LOA application shows the overlap of the humpback whale 
critical habitat with the TMAA. As shown in the Navy's rulemaking/LOA 
application, the TMAA overlaps with humpback whale

[[Page 632]]

critical habitat Unit 5 (destination for whales from the Hawaii, 
Mexico, and Western North Pacific DPSs; Calambokidis et al., 2008) and 
Unit 8 (destination for whales from the Hawaii and Mexico DPSs (Baker 
et al., 1986, Calambokidis et al., 2008); Western North Pacific DPS 
whales have not been photo-identified in this specific area, but 
presence has been inferred based on available data indicating that 
humpback whales from Western North Pacific wintering areas occur in the 
Gulf of Alaska (NMFS 2020, Table C5)). Approximately 4 percent of the 
humpback whale critical habitat in the GOA region overlaps with the 
TMAA, and approximately 2 percent of critical habitat in both the GOA 
and U.S. west coast regions combined overlaps with the TMAA. The WMA 
portion of the GOA Study Area does not overlap ESA-designated critical 
habitat for humpback whales. As noted above in the Geographical Region 
section, the TMAA boundary was intentionally designed to avoid ESA-
designated western DPS (MMPA western U.S. stock) Steller sea lion 
critical habitat.

Biologically Important Areas

    BIAs include areas of known importance for reproduction, feeding, 
or migration, or areas where small and resident populations are known 
to occur (Van Parijs, 2015). 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 BIAs may be found here: 
https://cetsound.noaa.gov/biologically-important-area-map.
    The WMA does not overlap with any known BIAs. BIAs in the GOA that 
overlap portions of the TMAA include the following feeding and 
migration areas: North Pacific right whale feeding BIA (June-
September); Gray whale migratory corridor BIA (November--January, 
southbound; March--May, northbound) (Ferguson et al., 2015). Fin whale 
feeding areas (east, west, and southwest of Kodiak Island) occur to the 
west of the TMAA and gray whale feeding areas occur both east 
(Southeast Alaska) and west (Kodiak Island) of the TMAA; however, these 
feeding areas are located well outside of (>20 nmi (37 km)) the TMAA 
and beyond the Navy's estimated range to effects for take by Level A 
harassment and Level B harassment.
    A portion of the North Pacific right whale feeding BIA overlaps 
with the western side of the TMAA by approximately 2,051 square 
kilometers (km\2\; approximately 1.4 percent of the TMAA, and 7 percent 
of the feeding BIA). A small portion of the gray whale migration 
corridor BIA also overlaps with the western side of the TMAA by 
approximately 1,582 km\2\ (approximately 1 percent of the TMAA, and 1 
percent of the migration corridor BIA). To mitigate impacts to marine 
mammals in these BIAs, the Navy will implement several procedural 
mitigation measures and mitigation areas (described in the Mitigation 
Measures section).

Unusual Mortality Events (UMEs)

    A 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. There is one UME that is 
applicable to our evaluation of the Navy's activities in the GOA Study 
Area. The gray whale UME along the west coast of North America is 
active and involves ongoing investigations in the GOA that inform our 
analysis are discussed below.
Gray Whale UME
    Since January 1, 2019, elevated gray whale strandings have occurred 
along the west coast of North America, from Mexico to Canada. As of 
September 21, 2022, there have been a total of 606 strandings along the 
coasts of the United States, Canada, and Mexico, with 300 of those 
strandings occurring along the U.S. coast. Of the strandings on the 
U.S. coast, 133 have occurred in Alaska, 70 in Washington, 16 in 
Oregon, and 81 in California. Full or partial necropsy examinations 
were conducted on a subset of the whales. Preliminary findings in 
several of the whales have shown evidence of emaciation. These findings 
are not consistent across all of the whales examined, so more research 
is needed. As part of the UME investigation process, NOAA has assembled 
an independent team of scientists to coordinate with the Working Group 
on Marine Mammal Unusual Mortality Events to review the data collected, 
sample stranded whales, consider possible causal-linkages between the 
mortality event and recent ocean and ecosystem perturbations, and 
determine the next steps for the investigation. Please refer to: 
https://www.fisheries.noaa.gov/national/marine-life-distress/2019-2022-gray-whale-unusual-mortality-event-along-west-coast-and for more 
information on this UME.

Species Not Included in the Analysis

    There has been no change in the species unlikely to be present in 
the GOA Study Area since the last MMPA rulemaking process (82 FR 19530; 
April 27, 2017). The species carried forward for analysis (and 
described in Table 6) are those likely to be found in the GOA 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 and stocks that may be present in the northeast Pacific Ocean 
generally have an extremely low probability of presence in the GOA 
Study Area. These species and stocks are considered extralimital (i.e., 
there may be sightings, acoustic detections, or stranding records, but 
the GOA Study Area is outside the species' range of normal occurrence) 
or rare (occur in the GOA Study Area sporadically, but sightings are 
rare). These species and stocks include the Eastern North Pacific 
Northern Resident and the West Coast Transient stocks of killer whale 
(Orcinus orca), beluga whale (Delphinapterus leucas), false killer 
whale (Pseudorca crassidens), short-finned pilot whale (Globicephala 
macrorhynchus), northern right whale dolphin (Lissodelphis borealis), 
and Risso's dolphin (Grampus griseus). These species are unlikely to 
occur in the GOA Study Area, and the reasons for not including each was 
explained in further detail in the proposed rule (87 FR 49656; August 
11, 2022).
    One species of marine mammal, the Northern sea otter, occurs in the 
Gulf of Alaska but is managed by the U.S. Fish and Wildlife Service and 
is not considered further in this document.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    We provided a detailed discussion of the potential effects of the 
specified activities on marine mammals and their habitat in our Federal 
Register notice of proposed rulemaking (87 FR 49656; August 11, 2022). 
In the Potential Effects of Specified Activities on Marine Mammals and 
Their Habitat section of the proposed rule, NMFS provided a description 
of the ways marine mammals may be affected by these activities in the 
form of, among other things, serious injury or mortality, physical 
trauma, sensory impairment (permanent and temporary threshold shift and 
acoustic masking), physiological responses (particularly stress 
responses), behavioral disturbance, or habitat effects. All of this 
information remains valid and applicable. Therefore, we do not reprint

[[Page 633]]

the information here, but refer the reader to that document.
    NMFS has also reviewed new relevant information from the scientific 
literature since publication of the proposed rule. Summaries of the new 
key scientific literature reviewed since publication of the proposed 
rule are presented below.
    Branstetter and Sills (2022) reviewed direct laboratory (i.e., 
psychoacoustic) studies of marine mammal hearing.
    Tougaard et al. (2022) reviewed the most recent temporary threshold 
shift (TTS) data from phocid seals and harbor porpoises, and compared 
empirical data to the predictive exposure functions put forth by 
Southall et al. (2019), which were based on data collected prior to 
2015. The authors concluded that more recent data supports the 
thresholds used for harbor porpoises (categorized as `very high 
frequency' (VHF) cetaceans), which over-estimated the hearing impact 
for sounds above 20 kHz in frequency. Similarly, the new data for 
phocid seals show TTS onset thresholds that are well-above the 
predicted levels for sounds below 5 kHz in frequency. However, phocid 
seals might be more sensitive to higher frequency sound exposures than 
predicted, as the TTS onset data for frequencies higher than 20 kHz was 
below the predicted levels. The interpretation of these data indicate 
that the criteria and thresholds used to estimate hearing impacts for 
VHF cetaceans and phocid seals have been conservative overall.
    Von Benda-Beckmann et al. (2022) assessed whether correcting for 
kurtosis, a measure of sound impulsiveness, improved the ability to 
predict temporary threshold shift (TTS) in a marine mammal. The 
conclusions from this study were that the kurtosis-corrected sound 
exposure levels (SELs) did not explain differences in TTS between 
intermittent and continuous sound exposures, likely because silent 
intervals provided an opportunity for hearing recovery that could not 
be accounted for by these models. Kurtosis might still be useful for 
evaluating sound exposure criteria for different types of sounds having 
various degrees of impulsiveness.
    Sweeney et al. (2022) examined the difference between noise impact 
analyses using unweighted broadband sound pressure levels (SPLs) and 
analyses using auditory weighting functions. The recordings used to 
conduct parallel analyses in three marine mammal species groups were 
from a shipping route in Canada. Since shipping noise was predominantly 
in the low-frequency spectrum, bowhead whales perceived similar 
weighted and unweighted SPLs while narwhals and ringed seals 
experienced lower SPLs when auditory weighting functions were used. The 
data provide a real-world example to support the use of weighting 
functions based on hearing sensitivity when estimating audibility and 
potential impact of vessel noise on marine mammals.
    An analysis subsequent to Varghese et al. (2020) suggested that the 
observed spatial shifts of Cuvier's beaked whales during multibeam 
echosounder activity on the Southern California Antisubmarine Warfare 
Range were most likely due to prey dynamics (Kates Varghese et al. 
2021).
    Manzano-Roth et al. (2022) found that cross seamount beaked whales 
reduced clusters of foraging pulses (Group Vocal Periods) during 
Submarine Command Course events and remained low for a minimum of three 
days after the MFA sonar activity. This is consistent with the findings 
of previous studies of beaked whale responses to sonar discussed in the 
proposed rule (87 FR 49656; August 11, 2022).
    K[ouml]nigson et al. (2021) tested the efficacy of Banana Pingers 
(300 ms, 59-130 kHz frequency modulated, 133-139 dBrms re 1 [mu]Pa at 1 
m source level) as a deterrent for harbor porpoise in Sweden. As 
described previously, these pingers were designed to avoid potential 
pinniped responses. Authors used recorded echolocation clicks with C-
PODs to measure the presence or absence of porpoise in the area. 
Porpoise were less likely to be detected at 0 m and within 100 m of an 
active pinger, but a pinger at 400 m appeared to have no effect.
    Pirotta et al. (2022) reviewed the development of bioenergetic 
models with a focus on applications to marine mammals.
    Having considered the new information, along with information 
provided in public comments on the proposed rule, we have determined 
that there is no new information that substantively affects our 
analysis of potential impacts on marine mammals and their habitat that 
appeared in the proposed rule, all of which remains applicable and 
valid for our assessment of the effects of the Navy's activities during 
the seven-year period of this rule.

Estimated Take of Marine Mammals

    This section indicates the number of takes that NMFS is 
authorizing, which is based on the amount of take that NMFS anticipates 
could occur or the maximum amount that is reasonably likely to occur, 
depending on the type of take and the methods used to estimate it, as 
described in detail below. NMFS coordinated closely with the Navy in 
the development of their incidental take application and agrees that 
the methods the Navy has 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 are in the form of harassment only. For a 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 such behavioral patterns are 
abandoned or significantly altered (Level B Harassment).
    Authorized takes will primarily be in the form of Level B 
harassment, as use of the acoustic and explosive sources (i.e., sonar 
and explosives) is more likely to result in behavioral disturbance 
(rising to the level of a take as described above) or temporary 
threshold shift (TTS) for marine mammals than other forms of take. 
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 training activities.
    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 
will be taken by behavioral disturbance (in this case, as defined in 
the military readiness definition of Level B harassment included above) 
or incur some degree of temporary or permanent hearing impairment; (2) 
the area or volume of water that will 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. Below, we describe these components in more detail and 
present the take estimates.

Acoustic Thresholds

    Using the best available science, NMFS, in coordination with the 
Navy, has established acoustic thresholds that identify the most 
appropriate received level of underwater sound above which marine 
mammals exposed to these sound sources could be reasonably

[[Page 634]]

expected to experience 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) or permanent threshold shift (PTS) 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 detonations (although no 
non-auditory injury from explosives is anticipated as part of this 
rulemaking).
    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 
thresholds 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 
conservative 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 thresholds are the 
most appropriate method for predicting Level B harassment by behavioral 
disturbance given the best available science and the associated 
uncertainty.
Hearing Impairment (TTS/PTS) and Non-Auditory Tissue Damage and 
Mortality
    NMFS' Acoustic Technical Guidance (NMFS, 2018) identifies dual 
criteria to assess auditory injury (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 Acoustic Technical Guidance also 
identifies criteria to predict TTS, which is not considered injury and 
falls into the Level B harassment category. The Navy's planned activity 
includes the use of non-impulsive (sonar) and impulsive (explosives) 
sources.
    These thresholds (Table 7 and Table 8) were developed by compiling 
and synthesizing the best available science and soliciting input 
multiple times from both the public and peer reviewers. The references, 
analysis, and methodology used in the development of the thresholds are 
described in the Acoustic Technical Guidance, which may be accessed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

  Table 7--Acoustic Thresholds Identifying the Onset of TTS and PTS for
        Non-Impulsive Sound Sources by Functional Hearing Groups
------------------------------------------------------------------------
                                                   Non-impulsive
                                         -------------------------------
        Functional hearing group           TTS Threshold   PTS Threshold
                                          SEL (weighted)  SEL (weighted)
------------------------------------------------------------------------
Low-Frequency Cetaceans.................             179             199
Mid-Frequency Cetaceans.................             178             198
High-Frequency Cetaceans................             153             173
Phocid Pinnipeds (Underwater)...........             181             201
Otarid Pinnipeds (Underwater)...........             199             219
------------------------------------------------------------------------
Note: SEL thresholds in dB re: 1 [mu]Pa\2\s accumulated over a 24-hr
  period.

    Based on the best available science, the Navy (in coordination with 
NMFS) used the acoustic and pressure thresholds indicated in Table 8 to 
predict the onset of TTS, PTS, non-auditory tissue damage, and 
mortality for explosives (impulsive) and other impulsive sound sources.

                       Table 8--Thresholds for TTS, PTS, Tissue Damage, and Mortality Thresholds for Marine Mammals for Explosives
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                        Weighted onset TTS                         Slight GI tract       Slight lung
    Functional hearing group            Species                \1\           Weighted onset PTS         injury             injury           Mortality
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans.........  All mysticetes.....  168 dB SEL or 213    183 dB SEL or 219    243 dB Peak SPL....  Equation 1.       Equation 2.
                                                        dB Peak SPL.         dB Peak SPL.
Mid-frequency cetaceans.........  Most delphinids,     170 dB SEL or 224    185 dB SEL or 230    243 dB Peak SPL....  ................  ................
                                   medium and large     dB Peak SPL.         dB Peak SPL.
                                   toothed whales.
High-frequency cetaceans........  Porpoises and Kogia  140 dB SEL or 196    155 dB SEL or 202    243 dB Peak SPL....
                                   spp.                 dB Peak SPL.         dB Peak SPL.
Phocidae........................  Harbor seal,         170 dB SEL or 212    185 dB SEL or 218    243 dB Peak SPL....
                                   Hawaiian monk        dB Peak SPL.         dB Peak SPL.
                                   seal, Northern
                                   elephant seal.

[[Page 635]]

 
Otariidae.......................  California sea       188 dB SEL or 226    203 dB SEL or 232    243 dB Peak SPL....
                                   lion, Guadalupe      dB Peak SPL.         dB Peak SPL.
                                   fur seal, Northern
                                   fur seal.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: (1) Equation 1: 65.8M\1/3\ (1+[DRm/10.1])\1/6\ Pa-sec (2) Equation 2: 144M\1/3\ (1+[DRm/10.1])\1/6\ Pa-sec (3) M = mass of the animals in kg (4)
  DRm = depth of the receiver (animal) in meters (5) SPL = sound pressure level (6) Weighted SEL thresholds in dB re: 1 [mu]Pa\2\-s accumulated over a
  24-h period.
\1\ Peak thresholds are unweighted.

    The criteria used to assess the onset of TTS and PTS due to 
exposure to sonars (non-impulsive, see Table 7 above) are discussed 
further in the Navy's rulemaking/LOA application (see Hearing Loss from 
Sonar and Other Transducers in Chapter 6, Section 6.4.2.1, Methods for 
Analyzing Impacts from Sonars and Other Transducers). Refer to the 
``Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects 
Analysis (Phase III)'' report (U.S. Department of the Navy, 2017c) for 
detailed information on how the criteria and thresholds were derived, 
and to Section 3.8.3.1.1.2 of the 2022 GOA FSEIS/OEIS for a review of 
TTS research published following development of the criteria and 
thresholds applied in the Navy's analysis and in NMFS' Acoustic 
Technical Guidance. NMFS is aware of more recent papers (e.g., 
Kastelein et al., 2020d; Kastelein et al., 2021a and 2021b; Sills et 
al., 2020) and is currently working with the Navy to update NMFS' 
Technical Guidance for Assessing the Effects of Anthropogenic Sound on 
Marine Mammal Hearing Version 2.0 (Acoustic Technical Guidance; NMFS, 
2018) to reflect relevant papers that have been published since the 
2018 update on our 3-5 year update schedule in the Acoustic Technical 
Guidance. We note that the recent peer-reviewed updated marine mammal 
noise exposure criteria by Southall et al. (2019a) provide identical 
PTS and TTS thresholds and weighting functions to those provided in 
NMFS' Acoustic Technical Guidance.
    NMFS will continue to review and evaluate new relevant data as it 
becomes available and consider the impacts of those studies on the 
Acoustic Technical Guidance to determine what revisions/updates may be 
appropriate. However, any such revisions must undergo peer and public 
review before being adopted, as described in the Acoustic Guidance 
methodology. While some of the relevant data may potentially suggest 
changes to TTS/PTS thresholds for some species, any such changes would 
not be expected to change the predicted take estimates in a manner that 
would change the necessary determinations supporting the issuance of 
these regulations, and the data and values used in this rule reflect 
the best available science.
    Non-auditory injury (i.e., other than PTS) and mortality from sonar 
and other transducers is so unlikely as to be discountable under normal 
conditions for the reasons explained in the proposed rule under the 
Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat section--Acoustically-Induced Bubble Formation Due to Sonars 
and Other Pressure-related Impacts and is therefore not considered 
further in this analysis.
Level B Harassment by Behavioral Disturbance
    Though significantly driven by received level, the onset of Level B 
harassment by behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source (e.g., frequency, predictability, duty cycle), the environment 
(e.g., bathymetry), and the receiving animals (hearing, motivation, 
experience, demography, behavioral context) and can be difficult to 
predict (Ellison et al., 2011; Southall et al., 2007). Based on what 
the available science indicates and the practical need to use 
thresholds based on a factor, or factors, that are both predictable and 
measurable for most activities, NMFS uses generalized acoustic 
thresholds based primarily on received level (and distance in some 
cases) to estimate the onset of Level B harassment by behavioral 
disturbance.

Sonar

    As noted above, the Navy coordinated with NMFS to develop, and 
propose for use in this rule, 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 thresholds are referred 
to as ``behavioral harassment thresholds'' throughout the rest of this 
rule. These behavioral harassment thresholds consist of BRFs and 
associated cutoff distances, 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 
III)'' report (U.S. Department of the Navy, 2017c). 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 tactical sonar and 
other transducers. NMFS has carefully reviewed the Navy's criteria, 
i.e., BRFs and cutoff distances for these species, and agrees that they 
are the best available science and 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 rule. As noted above, NMFS will continue to 
review and evaluate new relevant data as it becomes available and 
consider the impacts of those studies on the Acoustic Technical 
Guidance.
    As discussed above, 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 
that there is support for considering alternative approaches for 
estimating Level B harassment by behavioral disturbance. Although the 
statutory definition of Level B harassment for military readiness 
activities means that a natural behavioral pattern of a marine mammal 
is significantly altered or abandoned, the current state of science for

[[Page 636]]

determining those thresholds is somewhat unsettled.
    In its analysis of impacts associated with sonar acoustic sources 
(which was coordinated with NMFS), the Navy used an updated 
conservative approach that likely overestimates the number of takes by 
Level B harassment due to behavioral disturbance and response. Many of 
the behavioral responses identified using the Navy's quantitative 
analysis are most likely to be of moderate severity as described in the 
Southall et al. (2007) 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 
Navy's quantitative analysis, many reactions are predicted from 
exposure to sound that may exceed an animal's threshold for Level B 
harassment by behavioral disturbance 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.'' The Navy and NMFS have used the best 
available science to address the challenging differentiation between 
significant and non-significant behavioral reactions (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 reactions 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). 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 Analysis and Negligible Impact 
Determination section and are authorized.
    In the Navy's acoustic impact analyses during Phase II (the 
previous phase of Navy testing and training, 2017-2022; see also Navy's 
``Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects 
Analysis (Phase III)'' technical report, 2012), the likelihood of Level 
B harassment by behavioral disturbance in response to sonar and other 
transducers was based on a probabilistic function (BRF), that related 
the likelihood (i.e., probability) of a behavioral response (at the 
level of a Level B harassment) to the received SPL. The BRF was used to 
estimate the percentage of an exposed population that is likely to 
exhibit Level B harassment due to altered behaviors or behavioral 
disturbance at a given received SPL. This BRF relied on the assumption 
that sound poses a negligible risk to marine mammals if they are 
exposed to SPL below a certain ``basement'' value. Above the basement 
exposure SPL, the probability of a response increased with increasing 
SPL. Two BRFs were used in Navy acoustic impact analyses: BRF1 for 
mysticetes and BRF2 for other species. BRFs were not used for beaked 
whales during Phase II analyses. Instead, a step function at an SPL of 
140 dB re: 1 [mu]Pa was used for beaked whales as the threshold to 
predict Level B harassment by behavioral disturbance. Similarly, a 120 
dB re: 1 [mu]P step function was used during Phase II for harbor 
porpoises.
    Developing the behavioral harassment criteria for Phase III (the 
current phase of Navy training and testing activities) involved 
multiple steps. All available behavioral response studies conducted 
both in the field and on captive animals were examined to understand 
the breadth of behavioral responses of marine mammals to sonar and 
other transducers (see also Navy's ``Criteria and Thresholds for U.S. 
Navy Acoustic and Explosive Effects Analysis (Phase III)'' Technical 
Report, 2017). Six behavioral response field studies with observations 
of 14 different marine mammal species reactions to sonar or sonar-like 
signals and 6 captive animal behavioral studies with observations of 8 
different species reactions to sonar or sonar-like signals were used to 
provide a robust data set for the derivation of the Navy's Phase III 
marine mammal behavioral response criteria. The current criteria have 
been rigorously vetted within the Navy community, among scientists 
during expert elicitation, and then reviewed by the public before being 
applied. All behavioral response research that has been published since 
the derivation of the Navy's Phase III criteria (December 2016) has 
been considered, and NMFS will continue to review and evaluate new 
relevant data as it becomes available and consider the impacts of those 
studies on the Acoustic Technical Guidance to determine what revisions/
updates may be appropriate. However, any such revisions must undergo 
peer and public review before being adopted, as described in the 
Acoustic Guidance methodology. In consideration of the available data, 
any such changes would not be expected to change the predicted take 
estimates in a manner that would change the necessary determinations 
supporting the issuance of these regulations, and the data and values 
used in this rule reflect the best available science.
    Marine mammal species were placed into behavioral criteria groups 
based on their known or suspected behavioral sensitivities to sound. In 
most cases these divisions were driven by taxonomic classifications 
(e.g., mysticetes, pinnipeds). The data from the behavioral studies 
were analyzed by looking for significant responses, or lack thereof, 
for each experimental session. The resulting four Bayesian Biphasic 
Dose Response Functions (referred to as the BRFs) that were developed 
for odontocetes, pinnipeds, mysticetes, and beaked whales predict the 
probability of a behavioral response qualifying as Level B harassment 
given exposure to certain received levels of sound. These BRFs are then 
used in combination with the cutoff distances described below to 
estimate the number of takes by Level B harassment.
    The Navy used cutoff distances beyond which the potential of 
significant behavioral responses (and therefore Level B harassment) is 
considered to be unlikely (see Table 9 below). These distances were 
determined by examining all available published field observations of 
behavioral reactions to sonar or sonar-like signals that included the 
distance between the sound source and the marine mammal. The longest 
distance, rounded up to the nearest 5-km increment, was chosen as the 
cutoff distance for each behavioral criteria group (i.e., odontocetes, 
pinnipeds, mysticetes, beaked whales, and harbor porpoise). For animals 
within the cutoff distance, BRFs for each behavioral criteria group 
based on a received SPL as presented in Chapter 6, Section 6.4.2.1 
(Methods for Analyzing Impacts from Sonars and other Transducers) of 
the Navy's rulemaking/LOA application was used to predict the 
probability of a potential significant behavioral response. For 
training activities that contain multiple platforms or tactical sonar 
sources that exceed 215 dB re: 1 [mu]Pa at 1 m, this cutoff distance is 
substantially increased (i.e., doubled) from values derived from the 
literature. The use of multiple platforms and intense sound sources are 
factors that probably increase responsiveness in marine mammals overall 
(however, we note that helicopter dipping sonars were considered in the 
intense sound source group, despite lower source levels,

[[Page 637]]

because of data indicating that marine mammals are sometimes more 
responsive to the less predictable employment of this source). There 
are currently few behavioral observations under these circumstances; 
therefore, the Navy conservatively predicted significant behavioral 
responses that will rise to Level B harassment at farther ranges as 
shown in Table 9, versus less intense events.

  Table 9--Cutoff Distances for Moderate Source Level, Single Platform
   Training Events and for All Other Events With Multiple Platforms or
   Sonar With Source Levels at or Exceeding 215 dB re: 1 [mu]Pa at 1 m
------------------------------------------------------------------------
                                           Moderate SL/
                                              single      High SL/multi-
             Criteria group                  platform        platform
                                              cutoff          cutoff
                                           distance (km)   distance (km)
------------------------------------------------------------------------
Odontocetes.............................              10              20
Pinnipeds...............................               5              10
Mysticetes..............................              10              20
Beaked Whales...........................              25              50
Harbor Porpoise.........................              20             40
------------------------------------------------------------------------
Notes: dB re: 1 [mu]Pa at 1 m = decibels referenced to 1 micropascal at
  1 meter, km = kilometer, SL = source level.

    The range to received sound levels in 6-dB steps from three 
representative sonar bins and the percentage of animals that may be 
taken by Level B harassment under each BRF are shown in Table 10 
through Table 12. Cells are shaded if the mean range value for the 
specified received level exceeds the distance cutoff distance for a 
particular group and therefore are not included in the estimated take. 
See Chapter 6, Section 6.4.2.1 (Methods for Analyzing Impacts from 
Sonars and Other Transducers) of the Navy's rulemaking/LOA application 
for further details on the derivation and use of the BRFs, thresholds, 
and the cutoff distances to identify takes by Level B harassment, which 
were coordinated with NMFS. As noted previously, NMFS carefully 
reviewed, and contributed to, the Navy's behavioral harassment 
thresholds (i.e., the BRFs and the cutoff distances) for the species, 
and agrees that these methods represent the best available science at 
this time for determining impacts to marine mammals from sonar and 
other transducers.
    Table 10 through Table 12 identify the maximum likely percentage of 
exposed individuals taken at the indicated received level and 
associated range (in which marine mammals would be reasonably expected 
to experience a disruption in behavior patterns to a point where they 
are abandoned or significantly altered) for mid-frequency active sonar 
(MFAS).
BILLING CODE 3510-22-P

[[Page 638]]

[GRAPHIC] [TIFF OMITTED] TR04JA23.105


[[Page 639]]


[GRAPHIC] [TIFF OMITTED] TR04JA23.106


[[Page 640]]


[GRAPHIC] [TIFF OMITTED] TR04JA23.107

BILLING CODE 3510-22-C

Explosives

    Phase III explosive thresholds for Level B harassment by behavioral 
disturbance for marine mammals is the hearing groups' TTS threshold (in 
SEL) minus 5 dB (see Table 13 below and Table 8 for the TTS thresholds 
for explosives) for events that contain multiple impulses from 
explosives underwater. This was the same approach as taken in Phase II 
for explosive analysis. See the ``Criteria and Thresholds for U.S. Navy 
Acoustic and Explosive Effects Analysis (Phase III)'' report (U.S. 
Department of the Navy, 2017c) for detailed information on how the 
criteria and thresholds were derived. NMFS continues to concur that 
this approach represents the best available science for determining 
impacts to marine mammals from explosives. As noted previously, 
detonations occurring in air at a height of 33 ft (10 m) or less above 
the water surface, and detonations occurring directly on the water 
surface were modeled to detonate at a depth of 0.3 ft (0.1 m) below the 
water surface. There are no detonations of explosives occurring 
underwater as part of the planned activities.

  Table 13--Thresholds for Level B Harassment by Behavioral Disturbance
                    for Explosives for Marine Mammals
------------------------------------------------------------------------
                                     Functional hearing
              Medium                        group         SEL (weighted)
------------------------------------------------------------------------
Underwater........................  Low-frequency                    163
                                     cetaceans.
Underwater........................  Mid-frequency                    165
                                     cetaceans.
Underwater........................  High-frequency                   135
                                     cetaceans.
Underwater........................  Phocids.............             165

[[Page 641]]

 
Underwater........................  Otariids............             183
------------------------------------------------------------------------
Note: Weighted SEL thresholds in dB re: 1 [mu]Pa\2\s underwater.

Navy's Acoustic Effects Model

    The Navy's Acoustic Effects Model calculates sound energy 
propagation from sonar and other transducers and explosives during 
naval activities and the sound received by animat dosimeters. Animat 
dosimeters are virtual representations of marine mammals distributed in 
the area around the modeled naval activity and each dosimeter records 
its individual sound ``dose.'' The model bases the distribution of 
animats over the TMAA, the portion of the GOA Study Area where sonar 
and other transducers and explosives are planned for use, on the 
density values in the Navy Marine Species Density Database 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 the Navy model intentionally err on the side of 
overestimation when there are unknowns. Naval activities are modeled as 
though they would occur regardless of proximity to marine mammals, 
meaning that no mitigation is considered (i.e., no power down or shut 
down modeled) and without any avoidance of the activity by the animal. 
The final step of the quantitative analysis of acoustic effects is to 
consider the implementation of mitigation and the possibility that 
marine mammals would avoid continued or repeated sound exposures. For 
more information on this process, see the discussion in the Take 
Requests subsection below. All explosives used in the TMAA will 
detonate in the air at or above the water surface. However, for this 
analysis, detonations occurring in air at a height of 33 ft. (10 m) or 
less above the water surface, and detonations occurring directly on the 
water surface were modeled to detonate at a depth of 0.3 ft. (0.1 m) 
below the water surface since there is currently no other identified 
methodology for modeling potential effects to marine mammals that are 
underwater as a result of detonations occurring at or above the surface 
of the ocean. This overestimates the amount of explosive and acoustic 
energy entering the water.
    The model estimates the impacts caused by individual training 
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 III Training and Testing'' (U.S. 
Department of the Navy, 2018).

Range to Effects

    The following section provides range to effects for sonar and other 
active acoustic sources as well as explosives to specific acoustic 
thresholds determined using the Navy Acoustic Effects Model. 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
    The ranges to received sound levels in 6-dB steps from three 
representative sonar bins and the percentage of the total number of 
animals that may exhibit a significant behavioral response (and 
therefore Level B harassment) under each BRF are shown in Table 10 
through Table 12 above, respectively. See Chapter 6, Section 6.4.2.1 
(Methods for Analyzing Impacts from Sonars and Other Transducers) of 
the Navy's rulemaking/LOA application for additional details on the 
derivation and use of the BRFs, thresholds, and the cutoff distances 
that are used to identify Level B harassment by behavioral disturbance. 
NMFS has reviewed the range distance to effect data provided by the 
Navy and concurs with the analysis.
    The ranges to PTS for three representative sonar systems for an 
exposure of 30 seconds is shown in Table 14 relative to the marine 
mammal's functional hearing group. This period (30 seconds) was chosen 
based on examining the maximum amount of time a marine mammal would 
realistically be exposed to levels that could cause the onset of PTS 
based on platform (e.g., ship) speed and a nominal animal swim speed of 
approximately 1.5 m per second. The ranges provided in the table 
include the average range to PTS, as well as the range from the minimum 
to the maximum distance at which PTS is possible for each hearing 
group.

[[Page 642]]



          Table 14--Ranges to Permanent Threshold Shift (meters) for Three Representative Sonar Systems
----------------------------------------------------------------------------------------------------------------
                                            Approximate range in meters for PTS from 30 second exposure \1\
            Hearing group             --------------------------------------------------------------------------
                                            Sonar bin MF1            Sonar bin MF4            Sonar bin MF5
----------------------------------------------------------------------------------------------------------------
High-frequency cetaceans.............            180 (180-180)               31 (30-35)                 9 (8-10)
Low-frequency cetaceans..............               65 (65-65)                13 (0-15)                  0 (0-0)
Mid-frequency cetaceans..............               16 (16-16)                  3 (3-3)                  0 (0-0)
Otariids \2\.........................                  6 (6-6)                  0 (0-0)                  0 (0-0)
Phocids \2\..........................               45 (45-45)               11 (11-11)                  0 (0-0)
----------------------------------------------------------------------------------------------------------------
\1\ PTS ranges extend from the sonar or other transducer sound source to the indicated distance. The average
  range to PTS is provided as well as the range from the estimated minimum to the maximum range to PTS in
  parenthesis.
\2\ Otariids and phocids are separated because true seals (phocids) generally dive much deeper than sea lions
  and fur seals (otariids).
Notes: MF = mid-frequency, PTS = permanent threshold shift.

    The tables below illustrate the range to TTS for 1, 30, 60, and 120 
seconds from three representative sonar systems (see Table 15 through 
Table 17).

          Table 15--Ranges to Temporary Threshold Shift (meters) for Sonar Bin MF1 over a Representative Range of Environments Within the TMAA
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                      Approximate TTS ranges (meters) \1\
                                                     ---------------------------------------------------------------------------------------------------
                    Hearing group                                                                Sonar Bin MF1
                                                     ---------------------------------------------------------------------------------------------------
                                                              1 second                30 seconds               60 seconds              120 seconds
--------------------------------------------------------------------------------------------------------------------------------------------------------
High-frequency cetaceans............................      3,554 (1,525-6,775)      3,554 (1,525-6,775)      5,325 (2,275-9,525)     7,066 (2,525-13,025)
Low-frequency cetaceans.............................          920 (850-1,025)          920 (850-1,025)      1,415 (1,025-2,025)      2,394 (1,275-4,025)
Mid-frequency cetaceans.............................            209 (200-210)            209 (200-210)            301 (300-310)            376 (370-390)
Otariids............................................               65 (65-65)               65 (65-65)            100 (100-110)            132 (130-140)
Phocids.............................................            673 (650-725)            673 (650-725)          988 (900-1,025)      1,206 (1,025-1,525)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Ranges to TTS represent the model predictions in different areas and seasons within the TMAA. The zone in which animals are expected to incur TTS
  extends from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum
  range to TTS in parenthesis.
Notes: MF = mid-frequency, TTS = temporary threshold shift.


          Table 16--Ranges to Temporary Threshold Shift (meters) for Sonar Bin MF4 Over a Representative Range of Environments Within the TMAA
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                      Approximate TTS ranges (meters) \1\
                                                     ---------------------------------------------------------------------------------------------------
                    Hearing group                                                                Sonar Bin MF4
                                                     ---------------------------------------------------------------------------------------------------
                                                              1 second                30 seconds               60 seconds              120 seconds
--------------------------------------------------------------------------------------------------------------------------------------------------------
High-frequency cetaceans............................            318 (220-550)          686 (430-1,275)          867 (575-1,525)        1,225 (825-2,025)
Low-frequency cetaceans.............................               77 (0-100)            175 (130-340)            299 (190-550)          497 (280-1,000)
Mid-frequency cetaceans.............................               22 (22-22)               35 (35-35)               50 (50-50)               71 (70-75)
Otariids............................................                  8 (8-8)               15 (15-15)               19 (19-19)               25 (25-25)
Phocids.............................................               67 (65-70)            123 (110-150)            172 (150-210)            357 (240-675)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Ranges to TTS represent the model predictions in different areas and seasons within the TMAA. The zone in which animals are expected to incur TTS
  extends from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum
  range to TTS in parenthesis.
Notes: MF = mid-frequency, TTS = temporary threshold shift.


          Table 17--Ranges to Temporary Threshold Shift (meters) for Sonar Bin MF5 over a Representative Range of Environments Within the TMAA
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                      Approximate TTS Ranges (meters) \1\
                                                     ---------------------------------------------------------------------------------------------------
                    Hearing group                                                                Sonar Bin MF5
                                                     ---------------------------------------------------------------------------------------------------
                                                              1 second                30 seconds               60 seconds              120 seconds
--------------------------------------------------------------------------------------------------------------------------------------------------------
High-frequency cetaceans............................            117 (110-140)            117 (110-140)            176 (150-320)            306 (210-800)
Low-frequency cetaceans.............................                 9 (0-12)                 9 (0-12)                13 (0-17)                19 (0-24)
Mid-frequency cetaceans.............................                  5 (0-9)                  5 (0-9)               12 (11-13)               18 (17-18)
Otariids............................................                  0 (0-0)                  0 (0-0)                  0 (0-0)                  0 (0-0)

[[Page 643]]

 
Phocids.............................................                 9 (8-10)                 9 (8-10)               14 (14-15)               21 (21-22)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Ranges to TTS represent the model predictions in different areas and seasons within the TMAA. The zone in which animals are expected to incur TTS
  extends from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum
  range to TTS in parenthesis.
Notes: MF = mid-frequency, TTS = temporary threshold shift.

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 Chapter 6, Section 6.5.2 (Impacts 
from Explosives) of the Navy's rulemaking/LOA application and the 
``Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects 
Analysis (Phase III)'' report (U.S. Department of the Navy, 2017c)) and 
the explosive propagation calculations from the Navy Acoustic Effects 
Model (see Chapter 6, Section 6.5.2.2 (Impact Ranges for Explosives) of 
the Navy's rulemaking/LOA application). The range to effects are shown 
for a range of explosive bins, from E5 (greater than 5-10 lbs (2.3-4.5 
kg) net explosive weight) to E12 (greater than 650 lbs to 1,000 lbs 
(294.8-453.6 kg) net explosive weight) (Table 18 through Table 31). 
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 harassment), TTS, PTS, and non-auditory injury. 
NMFS has reviewed the range distance to effect data provided by the 
Navy 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 physiological effects 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 III Training and Testing'' (U.S. Navy, 2018).
    Table 18 through 29 show the minimum, average, and maximum ranges 
to onset of auditory and likely behavioral effects that rise to the 
level of Level B harassment 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. 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. Ranges to non-
auditory injury and mortality are shown in Table 30 and Table 31, 
respectively.
    No underwater detonations are planned as part of the Navy's 
activities, but marine mammals could be exposed to in-air detonations 
at or above the water surface. The Navy Acoustic Effects Model cannot 
account for the highly non-linear effects of cavitation and surface 
blow off for shallow underwater explosions, nor can it estimate the 
explosive energy entering the water from a low-altitude detonation. 
Thus, for this analysis, sources detonating in-air at or above (within 
10 m above) the water surface are modeled as if detonating completely 
underwater at a depth of 0.1 m, with all energy reflected into the 
water rather than released into the air. Therefore, the amount of 
explosive and acoustic energy entering the water, and consequently the 
estimated ranges to effects, are likely to be overestimated.
    Table 18 shows the minimum, average, and maximum ranges to onset of 
auditory and likely behavioral effects that rise to the level of Level 
B harassment for high-frequency cetaceans based on the developed 
thresholds.

      Table 18--SEL-Based Ranges to Onset PTS, Onset TTS, and Level B Harassment by Behavioral Disturbance (in meters) for High-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                              Range to effects for explosives: high-frequency cetaceans \1\
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Source depth
                   Bin \2\                           (m)        Cluster size             PTS                      TTS                   Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E5...........................................             0.1               1            910 (850-975)      1,761 (1,275-2,275)      2,449 (1,775-3,275)
                                               ..............               7      1,275 (1,025-1,525)      3,095 (2,025-4,525)      4,664 (2,275-7,775)
E9...........................................             0.1               1      1,348 (1,025-1,775)      3,615 (2,025-5,775)      5,365 (2,525-8,525)
E10..........................................             0.1               1      1,546 (1,025-2,025)      4,352 (2,275-7,275)      5,949 (2,525-9,275)
E12..........................................             0.1               1      1,713 (1,275-2,025)      5,115 (2,275-7,775)     6,831 (2,775-10,275)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses.
  Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive
  energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating ranges to effect. PTS = permanent
  threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).


[[Page 644]]

    Table 19 shows the minimum, average, and maximum ranges to onset of 
auditory effects for high-frequency cetaceans based on the developed 
thresholds.

    Table 19--Peak Pressure-Based Ranges to Onset PTS and Onset TTS (in meters) for High Frequency Cetaceans
----------------------------------------------------------------------------------------------------------------
                          Range to effects for explosives: high-frequency cetaceans \1\
-----------------------------------------------------------------------------------------------------------------
                                 Source depth
            Bin \2\                   (m)        Cluster size             PTS                      TTS
----------------------------------------------------------------------------------------------------------------
E5............................             0.1               1      1,161 (1,000-1,525)      1,789 (1,025-2,275)
                                ..............               7      1,161 (1,000-1,525)      1,789 (1,025-2,275)
E9............................             0.1               1      2,331 (1,525-2,775)      5,053 (2,025-9,275)
E10...........................             0.1               1      2,994 (1,775-4,525)     7,227 (2,025-14,775)
E12...........................             0.1               1      4,327 (2,025-7,275)    10,060 (2,025-22,275)
----------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation
  environments in parentheses. No underwater explosions are planned. The model assumes that all explosive energy
  from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
  ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).

    Table 20 shows the minimum, average, and maximum ranges to onset of 
auditory and likely behavioral effects that rise to the level of Level 
B harassment for low-frequency cetaceans based on the developed 
thresholds.

      Table 20--SEL-Based Ranges to Onset PTS, Onset TTS, and Level B Harassment by Behavioral Disturbance (in meters) for Low-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                              Range to effects for explosives: low-frequency cetaceans \1\
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Source depth
                   Bin \2\                           (m)        Cluster size             PTS                      TTS                   Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E5...........................................             0.1               1            171 (100-190)            633 (230-825)          934 (310-1,525)
                                               ..............               7            382 (170-450)        1,552 (380-5,775)       3,712 (600-13,025)
E9...........................................             0.1               1            453 (180-550)        3,119 (550-9,025)     6,462 (1,275-19,275)
E10..........................................             0.1               1            554 (210-700)       4,213 (600-13,025)     9,472 (1,775-27,275)
E12..........................................             0.1               1            643 (230-825)     6,402 (1,275-19,775)    13,562 (2,025-34,775)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses.
  Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive
  energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating ranges to effect. PTS = permanent
  threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).

    Table 21 shows the minimum, average, and maximum ranges to onset of 
auditory effects for low-frequency cetaceans based on the developed 
thresholds.

     Table 21--Peak Pressure-Based Ranges to Onset PTS and Onset TTS (in meters) for Low Frequency Cetaceans
----------------------------------------------------------------------------------------------------------------
                          Range to effects for explosives: low-frequency cetaceans \1\
-----------------------------------------------------------------------------------------------------------------
                                 Source depth
            Bin \2\                   (m)        Cluster size             PTS                      TTS
----------------------------------------------------------------------------------------------------------------
E5............................             0.1               1            419 (170-500)            690 (210-875)
                                ..............               7            419 (170-500)            690 (210-875)
E9............................             0.1               1          855 (270-1,275)        1,269 (400-1,775)
E10...........................             0.1               1          953 (300-1,525)        1,500 (450-2,525)
E12...........................             0.1               1        1,135 (360-1,525)        1,928 (525-4,775)
----------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation
  environments in parentheses. No underwater explosions are planned. The model assumes that all explosive energy
  from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
  ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).

    Table 22 shows the minimum, average, and maximum ranges to onset of 
auditory and likely behavioral effects that rise to the level of Level 
B harassment for mid-frequency cetaceans based on the developed 
thresholds.

[[Page 645]]



      Table 22--SEL-Based Ranges to Onset PTS, Onset TTS, and Level B Harassment by Behavioral Disturbance (in meters) for Mid-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                              Range to effects for explosives: mid-frequency cetaceans \1\
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Source depth
                   Bin \2\                           (m)        Cluster size             PTS                      TTS                   Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E5...........................................             0.1               1               79 (75-80)            363 (360-370)            581 (550-600)
                                               ..............               7            185 (180-190)            777 (650-825)        1,157 (800-1,275)
E9...........................................             0.1               1            215 (210-220)            890 (700-950)        1,190 (825-1,525)
E10..........................................             0.1               1            275 (270-280)          974 (750-1,025)        1,455 (875-1,775)
E12..........................................             0.1               1            340 (340-340)        1,164 (825-1,275)        1,746 (925-2,025)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses.
  Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive
  energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating ranges to effect. PTS = permanent
  threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).

    Table 23 shows the minimum, average, and maximum ranges to onset of 
auditory effects for mid-frequency cetaceans based on the developed 
thresholds.

     Table 23--Peak Pressure-Based Ranges to Onset PTS and Onset TTS (in meters) for Mid-Frequency Cetaceans
----------------------------------------------------------------------------------------------------------------
                          Range to effects for explosives: mid-frequency cetaceans \1\
-----------------------------------------------------------------------------------------------------------------
                                 Source depth
            Bin \2\                   (m)        Cluster size             PTS                      TTS
----------------------------------------------------------------------------------------------------------------
E5............................             0.1               1            158 (150-160)            295 (290-300)
                                ..............               7            158 (150-160)            295 (290-300)
E9............................             0.1               1            463 (430-470)            771 (575-850)
E10...........................             0.1               1            558 (490-575)          919 (625-1,025)
E12...........................             0.1               1            679 (550-725)        1,110 (675-1,275)
----------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation
  environments in parentheses. No underwater explosions are planned. The model assumes that all explosive energy
  from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
  ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).

    Table 24 shows the minimum, average, and maximum ranges to onset of 
auditory and likely behavioral effects that rise to the level of Level 
B harassment for otariid pinnipeds based on the developed thresholds.

              Table 24--SEL-Based Ranges to Onset PTS, Onset TTS, and Level B Harassment by Behavioral Disturbance (in meters) for Otariids
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      Range to effects for explosives: otariids \1\
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Source depth
                   Bin \2\                           (m)        Cluster size             PTS                      TTS                   Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E5...........................................             0.1               1               25 (24-25)            110 (110-110)            185 (180-190)
                                               ..............               7               58 (55-60)            265 (260-270)            443 (430-450)
E9...........................................             0.1               1               68 (65-70)            320 (310-330)            512 (490-525)
E10..........................................             0.1               1               88 (85-90)            400 (390-410)            619 (575-675)
E12..........................................             0.1               1            105 (100-110)            490 (470-500)            733 (650-825)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses.
  Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive
  energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating ranges to effect. PTS = permanent
  threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).

    Table 25 shows the minimum, average, and maximum ranges to onset of 
auditory effects for otariid pinnipeds based on the developed 
thresholds.

[[Page 646]]



            Table 25--Peak Pressure-Based Ranges to Onset PTS and Onset TTS (in meters) for Otariids
----------------------------------------------------------------------------------------------------------------
                                  Range to effects for explosives: otariids \1\
-----------------------------------------------------------------------------------------------------------------
                                 Source depth
            Bin \2\                   (m)        Cluster size             PTS                      TTS
----------------------------------------------------------------------------------------------------------------
E5............................             0.1               1            128 (120-130)            243 (240-250)
                                ..............               7            128 (120-130)            243 (240-250)
E9............................             0.1               1            383 (380-390)            656 (600-700)
E10...........................             0.1               1            478 (470-480)            775 (675-850)
E12...........................             0.1               1            583 (550-600)          896 (750-1,025)
----------------------------------------------------------------------------------------------------------------
\1\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation
  environments in parentheses. No underwater explosions are planned. The model assumes that all explosive energy
  from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
  ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\2\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).

    Table 26 shows the minimum, average, and maximum ranges to onset of 
auditory and likely behavioral effects that rise to the level of Level 
B harassment for phocid pinnipeds, excluding elephant seals, based on 
the developed thresholds.

 Table 26--SEL-Based Ranges to Onset PTS, Onset TTS, and Level B Harassment by Behavioral Disturbance (in meters) for Phocids, Excluding Elephant Seals
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      Range to effects for explosives: phocids \1\
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Source depth
                   Bin \2\                           (m)        Cluster size             PTS                      TTS                   Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E5...........................................             0.1               1            150 (150-150)            681 (675-700)        1,009 (975-1,025)
                                               ..............               7            360 (350-370)      1,306 (1,025-1,525)      1,779 (1,275-2,275)
E9...........................................             0.1               1            425 (420-430)      1,369 (1,025-1,525)      2,084 (1,525-2,775)
E10..........................................             0.1               1            525 (525-525)      1,716 (1,275-2,275)      2,723 (1,525-4,025)
E12..........................................             0.1               1            653 (650-675)      1,935 (1,275-2,775)      3,379 (1,775-5,775)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Excluding elephant seals.
\2\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation environments in parentheses. No underwater
  explosions are planned. The model assumes that all explosive energy from detonations at or above (within 10 m) the water surface is released
  underwater, likely over-estimating ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\3\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).

    Table 27 shows the minimum, average, and maximum ranges to onset of 
auditory effects for phocids pinnipeds, excluding elephant seals, based 
on the developed thresholds.

   Table 27--Peak Pressure-Based Ranges to Onset PTS and Onset TTS (in meters) for Phocids, Excluding Elephant
                                                      Seals
----------------------------------------------------------------------------------------------------------------
                                  Range to effects for explosives: phocids \1\
-----------------------------------------------------------------------------------------------------------------
                                 Source depth
            Bin \2\                   (m)        Cluster size             PTS                      TTS
----------------------------------------------------------------------------------------------------------------
E5............................             0.1               1            537 (525-550)            931 (875-975)
                                ..............               7            537 (525-550)            931 (875-975)
E9............................             0.1               1      1,150 (1,025-1,275)      1,845 (1,275-2,525)
E10...........................             0.1               1      1,400 (1,025-1,775)      2,067 (1,275-2,525)
E12...........................             0.1               1      1,713 (1,275-2,025)      2,306 (1,525-2,775)
----------------------------------------------------------------------------------------------------------------
\1\ Excluding elephant seals.
\2\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation
  environments in parentheses. No underwater explosions are planned. The model assumes that all explosive energy
  from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
  ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\3\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).

    Table 28 shows the minimum, average, and maximum ranges to onset of 
auditory and likely behavioral effects that rise to the level of Level 
B harassment for elephant seals based on the developed thresholds.

[[Page 647]]



         Table 28--SEL-Based Ranges to Onset PTS, Onset TTS, and Level B Harassment by Behavioral Disturbance (in meters) for Elephant Seals \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                              Range to effects for explosives: phocids (elephant seals) \2\
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Source depth
                   Bin \3\                           (m)        Cluster size             PTS                      TTS                   Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E5...........................................             0.1               1            150 (150-150)            688 (675-700)      1,025 (1,025-1,025)
                                               ..............               7            360 (350-370)      1,525 (1,525-1,525)      2,345 (2,275-2,525)
E9...........................................             0.1               1            425 (420-430)      1,775 (1,775-1,775)      2,858 (2,775-3,275)
E10..........................................             0.1               1            525 (525-525)      2,150 (2,025-2,525)      3,421 (3,025-4,025)
E12..........................................             0.1               1            656 (650-675)      2,609 (2,525-3,025)      4,178 (3,525-5,775)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Elephant seals are separated from other phocids due to their dive behavior, which far exceeds the dive depths of the other phocids analyzed.
\2\ Average distance (meters) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses.
  Values depict the range produced by SEL hearing threshold criteria levels. No underwater explosions are planned. The model assumes that all explosive
  energy from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating ranges to effect. PTS = permanent
  threshold shift, SEL = sound exposure level, TTS = temporary threshold shift.
\3\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).

    Table 29 shows the minimum, average, and maximum ranges to onset of 
auditory effects for elephant seals, based on the developed thresholds.

       Table 29--Peak Pressure-Based Ranges to Onset PTS and Onset TTS (in meters) for Elephant Seals \1\
----------------------------------------------------------------------------------------------------------------
                          Range to Effects for Explosives: phocids (elephant seals) \2\
-----------------------------------------------------------------------------------------------------------------
                                 Source depth
            Bin \3\                   (m)        Cluster size             PTS                      TTS
----------------------------------------------------------------------------------------------------------------
E5............................             0.1               1            537 (525-550)            963 (950-975)
                                ..............               7            537 (525-550)            963 (950-975)
E9............................             0.1               1      1,275 (1,275-1,275)      2,525 (2,525-2,525)
E10...........................             0.1               1      1,775 (1,775-1,775)      3,046 (3,025-3,275)
E12...........................             0.1               1      2,025 (2,025-2,025)      3,539 (3,525-3,775)
----------------------------------------------------------------------------------------------------------------
\1\ Elephant seals are separated from other phocids due to their dive behavior, which far exceeds the dive
  depths of the other phocids analyzed.
\2\ Average distance (meters) is shown with the minimum and maximum distances due to varying propagation
  environments in parentheses. No underwater explosions are planned. The model assumes that all explosive energy
  from detonations at or above (within 10 m) the water surface is released underwater, likely over-estimating
  ranges to effect. PTS = permanent threshold shift, TTS = temporary threshold shift.
\3\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).

    Table 30 shows the minimum, average, and maximum ranges due to 
varying propagation conditions to non-auditory injury as a function of 
animal mass and explosive bin (i.e., net explosive weight). Ranges to 
gastrointestinal tract injury typically exceed ranges to slight lung 
injury; therefore, the maximum range to effect is not mass-dependent. 
Animals within these water volumes 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 30--Ranges to 50 Percent Non-Auditory Injury for All Marine Mammal
                             Hearing Groups
------------------------------------------------------------------------
                                                        Range to non-
                      Bin \1\                          auditory injury
                                                        (meters) \2\
------------------------------------------------------------------------
E5................................................            40 (40-40)
E9................................................          121 (90-130)
E10...............................................         152 (100-160)
E12...............................................         190 (110-200)
------------------------------------------------------------------------
\1\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10
  (>250-500), E12 (>650-1,000).
\2\ Average distance (m) is shown with the minimum and maximum distances
  due to varying propagation environments in parentheses.
Notes: All ranges to non-auditory injury within this table are driven by
  gastrointestinal tract injury thresholds regardless of animal mass.

    Ranges to mortality, based on animal mass, are shown in Table 31 
below.

 Table 31--Ranges to 50 Percent Mortality Risk for All Marine Mammal Hearing Groups as a Function of Animal Mass
----------------------------------------------------------------------------------------------------------------
                                                             Animal mass intervals (kg) \2\
                Bin \1\                -------------------------------------------------------------------------
                                             10          250         1,000        5,000       25,000     72,000
----------------------------------------------------------------------------------------------------------------
E5....................................   13 (12-14)     7 (4-11)      3 (3-4)      2 (1-3)    1 (1-1)    1 (0-1)
E9....................................   35 (30-40)   20 (13-30)    10 (9-13)      7 (6-9)    4 (3-4)    3 (2-3)
E10...................................   43 (40-50)   25 (16-40)   13 (11-16)     9 (7-11)    5 (4-5)    4 (3-4)
E12...................................   55 (50-60)   30 (20-50)   17 (14-20)    11 (9-14)    6 (5-7)    5 (4-6)
----------------------------------------------------------------------------------------------------------------
\1\ Bin (net explosive weight, lb.): E5 (>5-10), E9 (>100-250), E10 (>250-500), E12 (>650-1,000).
\2\ Average distance (m) to mortality is depicted above the minimum and maximum distances, which are in
  parentheses for each animal mass interval.


[[Page 648]]

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). The result provides one 
single density estimate value for each species across broad geographic 
areas. 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 developed by NMFS' 
Southwest Fisheries Science Center has been used to estimate cetacean 
densities (Barlow et al., 2009; Becker et al., 2010, 2012a, b, c, 2014, 
2016, 2017, 2020; Ferguson et al., 2006a; Forney et al., 2012, 2015; 
Redfern et al., 2006). 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 
Navy activities on marine species. However, in many places, ship 
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 marine species density for large oceanic regions, 
the Navy reviews, critically assesses, and prioritizes 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 Navy Marine Species Density Database (NMSDD). NMFS 
vetted all cetacean densities by the Navy prior to use in the Navy's 
acoustic analysis for the current rulemaking process.
    A variety of density data and density models are needed in order to 
develop a density database that encompasses the entirety of the TMAA 
(densities beyond the TMAA were not considered because sonar and other 
transducers and explosives would not be used in the GOA Study Area 
beyond the TMAA). Because this data is collected using different 
methods with varying amounts of accuracy and uncertainty, the Navy has 
developed a hierarchy to ensure the most accurate data is used when 
available. The ``U.S. Navy Marine Species Density Database Phase III 
for the Gulf of Alaska Temporary Maritime Activities Area'' (U.S. 
Department of the Navy, 2021), hereafter referred to as the Density 
Technical Report, describes these models in detail and provides 
detailed explanations of the models applied to each species density 
estimate. The list below describes models in order of preference.
    1. Spatial density 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 Becker et al., 2016; Forney et al., 2015) predict spatial 
variability of animal presence as a function of habitat variables 
(e.g., sea surface temperature, seafloor depth, etc.). This model is 
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.
    2. Stratified design-based density estimates use line-transect 
survey data with the sampling area divided (stratified) into sub-
regions, and a density is predicted for each sub-region (see Barlow, 
2016; Becker et al., 2016; Bradford et al., 2017; Campbell et al., 
2014; Jefferson et al., 2014). While geographically stratified density 
estimates provide a better indication of a species' distribution within 
the study area, the uncertainty is typically high because each sub-
region estimate is based on a smaller stratified segment of the overall 
survey effort.
    3. Design-based density estimations use line-transect survey data 
from land and aerial surveys designed to cover a specific geographic 
area (see Carretta et al., 2015). These estimates use the same survey 
data as stratified design-based estimates, but are not segmented into 
sub-regions and instead provide one estimate for a large surveyed area.
    Relative environmental suitability (RES) models provide estimates 
for areas of the oceans that have not been surveyed using information 
on species occurrence and inferred habitat associations and have been 
used in past density databases, however, these models were not used in 
the current quantitative analysis.
    The Navy describes some of the challenges of interpreting the 
results of the quantitative analysis summarized above and described in 
the Density Technical Report: ``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

[[Page 649]]

to marine mammal 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 (U.S. Department of the Navy, 2017a).''
    Models may be based on different data sets or may generate 
different temporal predictions, and in this instance, the Navy's 
estimate of abundance (based on the density estimates used) in the TMAA 
may differ from population abundances estimated in NMFS' SARs in some 
cases for a variety of reasons. The SARs are often based on single 
years of NMFS surveys, whereas the models used by the Navy generally 
include multiple years of survey data from NMFS, the Navy, and other 
sources. To present a single, best estimate, the SARs often use a 
single season survey where they have the best spatial coverage 
(generally summer). Navy models often use predictions for multiple 
seasons, where appropriate for the species, even when survey coverage 
in non-summer seasons is limited, to characterize impacts over multiple 
seasons as Navy activities may occur outside of the summer months. 
Predictions may be made for different spatial extents. Many different, 
but equally valid, habitat and density modeling techniques exist and 
these can also be the cause of differences in population predictions. 
Differences in population estimates may be caused by a combination of 
these factors. Even similar estimates should be interpreted with 
caution and differences in models fully understood before drawing 
conclusions.
    In particular, the global population structure of humpback whales, 
with 14 DPSs all associated with multiple feeding areas at which 
individuals from multiple DPSs convene, is another reason that SAR 
abundance estimates can differ from other estimates and be somewhat 
confusing. 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 GOA Study Area or TMAA boundaries. 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.
    These factors and others described in the Density Technical Report 
should be considered when examining the estimated impact numbers in 
comparison to current population abundance information for any given 
species or stock. For a detailed description of the density and 
assumptions made for each species, see the Density Technical Report.
    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 
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.

Take Estimation

    The 2022 GOA FSEIS/OEIS considered all training activities planned 
to occur in the GOA Study Area. The Navy's rulemaking/LOA application 
described the activities that are reasonably likely to result in the 
MMPA-defined take of marine mammals, all of which will occur in the 
TMAA portion of the GOA Study Area. The Navy determined that the two 
stressors below could result in the incidental taking of marine 
mammals. NMFS has reviewed the Navy's 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 Navy's planned activities:
     Acoustics (sonar and other transducers);
     Explosives (explosive shock wave and sound, assumed to 
encompass the risk due to fragmentation).
    The quantitative analysis process used for the 2022 GOA FSEIS/OEIS 
and the Navy's take request in the rulemaking/LOA application to 
estimate potential exposures to marine mammals resulting from acoustic 
and explosive stressors is described above and further detailed in the 
technical report titled ``Quantifying Acoustic Impacts on Marine 
Mammals and Sea Turtles: Methods and Analytical Approach for Phase III 
Training and Testing'' (U.S. Department of the Navy, 2018). The Navy 
Acoustic Effects Model (NAEMO) brings together scenario simulations of 
the Navy's activities, sound propagation modeling, and marine mammal 
distribution (based on density and group size) by species to model and 
quantify the exposure of marine mammals above identified thresholds for 
behavioral harassment, TTS, PTS, non-auditory injury, and mortality.
    NAEMO estimates acoustic and explosive effects without taking 
mitigation into account; therefore, the model overestimates predicted 
impacts on marine mammals within mitigation zones. To account for 
mitigation for marine species in the take estimates, the Navy conducts 
a quantitative assessment of mitigation. The Navy conservatively 
quantifies the manner in which procedural mitigation is expected to 
reduce the risk for model-estimated PTS for exposures to sonars and for 
model-estimated mortality for exposures to explosives, based on species 
sightability, observation area, visibility, and the ability to exercise 
positive control over the sound source. See the proposed rule (87 FR 
49656; August 11, 2022) for a description of the process for assessing 
the effectiveness of procedural mitigation measures, along with the 
process for assessing the potential for animal avoidance. Where the 
analysis indicates mitigation would effectively reduce risk, the model-
estimated PTS takes are considered reduced to TTS and the model-
estimated mortalities are considered reduced to injury, though, for 
training activities in the GOA Study Area, no mortality or non-auditory 
injury is anticipated, even without consideration of planned mitigation 
measures. For a complete explanation of the process for assessing the 
effects of mitigation, see the Navy's rulemaking/LOA application 
(Section 6: Take Estimates for Marine Mammals, and Section 11: 
Mitigation Measures) and the technical report titled ``Quantifying 
Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and 
Analytical Approach for Phase III Training and Testing'' (U.S. 
Department of the Navy, 2018). The extent to which the mitigation areas 
reduce impacts on the affected species is addressed separately in the 
Analysis and Negligible Impact Determination section.
    NMFS coordinated with the Navy in the development of this 
quantitative method to address the effects of procedural mitigation on 
acoustic and explosive exposures and takes, and NMFS independently 
reviewed and concurs with the Navy that it is appropriate to 
incorporate the quantitative assessment of mitigation into the take 
estimates based on the best available science. We reiterate, however, 
that no mortality was modeled for the GOA TMAA activities, and, as 
stated above, the Navy does not propose the use of sonar and other 
transducers and explosives in the WMA. Therefore, this method was not 
applied here, as it

[[Page 650]]

relates to modeled mortality. This method was applied to potential 
takes by PTS resulting from sonar and other transducers in the TMAA, 
but not for the use of explosives.
    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 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 Navy's take estimation process have 
been used in Navy incidental take rules since 2009 and have 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, the NAEMO model 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 the NAEMO model (CASS/
GRAB) is accredited by the Oceanographic and Atmospheric Master Library 
(OAML), and many of the environmental variables used in the NAEMO model 
come from approved OAML databases and are based on in-situ data 
collection. The animal density components of the NAEMO model 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. Others like the 
Atlantic Marine Assessment Program for Protected Species, which was 
conducted by NMFS Science Centers, have undergone quality assurance and 
quality control (QA/QC) processes. Finally, the NAEMO model simulation 
components underwent 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 Navy's methods, including the underlying 
NAEMO modeling and the method for incorporating mitigation and 
avoidance, are the most appropriate methods for predicting non-auditory 
injury, PTS, TTS, and behavioral disturbance. But even with the 
consideration of mitigation and 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 non-auditory injury, PTS, TTS, or behavioral disturbance.
Summary of Estimated Take From Training Activities
    Based on the methods discussed in the previous sections and the 
Navy's model and quantitative assessment of mitigation, the Navy 
provided its take estimate and request for authorization of takes 
incidental to the use of acoustic and explosive sources for training 
activities both annually (based on the maximum number of activities 
that could occur per 12-month period) and over the 7-year period 
covered by the Navy's rulemaking/LOA application. The following 
species/stocks present in the TMAA were modeled by the Navy and 
estimated to have 0 takes of any type from any activity source: Western 
North Pacific stock of humpback whale; Eastern North Pacific and 
Western North Pacific stocks of gray whales; Eastern North Pacific 
Alaska Resident and AT1 Transient stocks of killer whales; Gulf of 
Alaska and Southeast Alaska stocks of harbor porpoises; U.S. stock of 
California sea lion; Eastern U.S. and Western U.S. stock of Steller sea 
lion; Cook Inlet/Shelikof Strait, North Kodiak, Prince William Sound, 
and South Kodiak stocks of harbor seals, and Alaska stock of Ribbon 
seals.
    The Phase II rule (82 FR 19530; April 26, 2017), valid from April 
2017 to April 2022, authorized Level B harassment take of the Eastern 
North Pacific Alaska Resident stock of killer whales, Gulf of Alaska 
and Southeast Alaska stocks of harbor porpoise, California sea lion, 
Eastern U.S. and Western U.S. stock of Steller sea lion, and South 
Kodiak and Prince William Sound stocks of harbor seal. Takes of these 
stocks in Phase II were all expected to occur as a result of exposure 
to sonar activity, rather than explosive use. Inclusion of new density/
distribution information and updated BRFs and corresponding cut-offs 
resulted in 0 estimated takes for these species and stocks in this 
rulemaking for Phase III.
    NMFS has reviewed the Navy's data, methodology, and analysis for 
the current phase of rulemaking (Phase III) and determined that it is 
complete and accurate. However, NMFS has conservatively authorized 
incidental take of the Western North Pacific stock of humpback whale 
and Eastern North Pacific stock of gray whale, for the following 
reasons. For the Western North Pacific stock of humpback whale, in 
calculating takes by Level B harassment from sonar in Phase III, the 
application of the Phase III BRFs with corresponding cut-offs (20 km 
for mysticetes), in addition to the stock guild breakout, which assigns 
0.05 percent of the take of humpback whales to the Western North 
Pacific stock, generated a near-zero result, which the Navy rounded to 
zero in its rulemaking/LOA application. However, NMFS authorized take 
of one Western North Pacific humpback whale in the Phase II LOA, and 
given that they do occur in the area, NMFS is conservatively 
authorizing take by Level B harassment of one group (3 animals) 
annually in this Phase III rulemaking. The annual take estimate of 3 
animals reflects the average group size of on and off-effort survey 
sightings of humpback whales reported in Rone et al. (2017). For the 
Eastern North Pacific stock of gray whales, application of the Phase 
III BRFs with corresponding cut-offs (20 km for mysticetes) resulted in 
true zero takes by Level B harassment for Phase III. However, Palacios 
et al. (2021) reported locations of three tagged gray whales within the 
TMAA as well as tracks of two additional gray whales that crossed the 
TMAA, and as noted previously, the TMAA overlaps with the gray whale 
migratory corridor BIA (November-January, southbound; March-May, 
northbound). As such, NMFS is conservatively authorizing take by Level 
B harassment of one group (4 animals) of Eastern North Pacific gray 
whales annually in this Phase III rulemaking. The annual take estimate 
of 4 animals reflects the average group sizes of on and off-effort 
survey sightings of gray whales (excluding an outlier of an estimated 
25 gray whales in one group) reported in Rone et al. (2017).

[[Page 651]]

    For all other species and stocks, 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 taken. NMFS also agrees that no 
mortality or serious injury is anticipated to occur, and no lethal take 
is authorized.
    For the Navy's training activities, Table 32 summarizes the Navy's 
take estimate and request and the maximum annual and 7-year total 
amount and type of Level A harassment and Level B harassment for the 7-
year period that NMFS anticipates is reasonably likely to occur 
(including the incidental take of Western North Pacific stock of 
humpback whale and Eastern North Pacific stock of gray whale, discussed 
above) by species and stock. Note that take by Level B harassment 
includes both behavioral disturbance and TTS. Tables 6-10 through 6-24 
(sonar and other transducers) and 6-41 through 6-49 (explosives) in 
Section 6 of the Navy's rulemaking/LOA application provide 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 32--Annual and 7-Year Total Species/Stock-Specific Take Estimates Authorized From Acoustic and Explosive
                          Sound Source Effects for All Training Activities in the TMAA
----------------------------------------------------------------------------------------------------------------
                                                                             Annual             7-Year total
                 Species                             Stock           -------------------------------------------
                                                                       Level B    Level A    Level B    Level A
----------------------------------------------------------------------------------------------------------------
                                                  Order Cetacea
                                       Suborder Mysticeti (baleen whales)
----------------------------------------------------------------------------------------------------------------
Family Balaenidae (right whales):
    North Pacific right whale *.........  Eastern North Pacific.....          3          0         21          0
Family Balaenopteridae (rorquals):
    Humpback whale......................  California, Oregon, &              10          0         70          0
                                           Washington *.
                                          Central North Pacific *...         79          0        553          0
                                          Western North Pacific *...      \a\ 3          0     \a\ 21          0
    Blue whale *........................  Central North Pacific.....          3          0         21          0
                                          Eastern North Pacific.....         36          0        252          0
    Fin whale *.........................  Northeast Pacific.........      1,242          2      8,694         14
    Sei whale *.........................  Eastern North Pacific.....         37          0        259          0
    Minke whale.........................  Alaska....................         50          0        350          0
Family Eschrichtiidae (gray whale):
    Gray whale..........................  Eastern North Pacific.....      \a\ 4          0     \a\ 28          0
----------------------------------------------------------------------------------------------------------------
                                      Suborder Odontoceti (toothed whales)
----------------------------------------------------------------------------------------------------------------
Family Delphinidae (dolphins):
    Killer whale........................  Eastern North Pacific,             81          0        567          0
                                           Offshore.
                                          Gulf of Alaska, Aleutian          143          0      1,003          0
                                           Island, & Bering Sea
                                           Transient.
    Pacific white-sided dolphin.........  North Pacific.............      1,574          0     11,018          0
Family Phocoenidae (porpoises):
    Dall's porpoise.....................  Alaska....................      9,287         64     65,009        448
Family Physeteridae (sperm whale):
    Sperm whale *.......................  North Pacific.............        112          0        784          0
Family Ziphiidae (beaked whales):
    Baird's beaked whale................  Alaska....................        106          0        742          0
    Cuvier's beaked whale...............  Alaska....................        433          0      3,031          0
    Stejneger's beaked whale............  Alaska....................        482          0      3,374          0
----------------------------------------------------------------------------------------------------------------
                                                 Order Carnivora
                                               Suborder Pinnipedia
----------------------------------------------------------------------------------------------------------------
Family Otarridae:
    Northern fur seal...................  Eastern Pacific...........      3,003          0     21,021          0
                                          California................         61          0        427          0
Family Phocidae (true seals):
    Northern elephant seal..............  California................      2,547          8     17,829         56
----------------------------------------------------------------------------------------------------------------
* ESA-listed species and stocks within the GOA Study Area.
\a\ The Navy's Acoustic Effects Model estimated zero takes for each of these stocks. However, NMFS
  conservatively authorized take by Level B harassment of one group of Western North Pacific humpback whale and
  one group of Eastern North Pacific gray whale. The annual take estimates reflect the average group sizes of on
  and off-effort survey sightings of humpback whale and gray whale (excluding an outlier of an estimated 25 gray
  whales in one group) reported in Rone et al. (2017).

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.
    In Conservation Council for Hawaii v. National Marine Fisheries 
Service, 97 F. Supp. 3d 1210, 1229 (D. Haw. 2015), the Court stated 
that NMFS ``appear[s] to think [it] satisf[ies] the statutory `least 
practicable adverse impact' requirement with a `negligible impact' 
finding.'' Expressing similar concerns in a challenge to a U.S. Navy 
Surveillance Towed Array Sensor System Low Frequency Active Sonar 
(SURTASS LFA) incidental take rule (77 FR 50290),

[[Page 652]]

the Ninth Circuit Court of Appeals in Natural Resources Defense Council 
(NRDC) v. Pritzker, 828 F.3d 1125, 1134 (9th Cir. 2016), stated, 
``[c]ompliance with the `negligible impact' requirement does not mean 
there [is] compliance with the `least practicable adverse impact' 
standard.'' As the Ninth Circuit noted in its opinion, however, the 
Court was interpreting the statute without the benefit of NMFS' formal 
interpretation. We state here explicitly that NMFS is in full agreement 
that the ``negligible impact'' and ``least practicable adverse impact'' 
requirements are distinct, even though both statutory standards refer 
to species and stocks. With that in mind, we provide further 
explanation of our interpretation of least practicable adverse impact, 
and explain what distinguishes it from the negligible impact standard. 
This discussion is consistent with previous rules we have issued, such 
as the Navy's Hawaii-Southern California Training and Testing (HSTT) 
rule (85 FR 41780; July 10, 2020), AFTT rule (84 FR 70712; December 23, 
2019), MITT rule (85 FR 46302; July 31, 2020), and NWTT rule (85 FR 
72312; November 12, 2020).
    Before NMFS can issue incidental take regulations under section 
101(a)(5)(A) of the MMPA, it must make a finding that the total taking 
will have a ``negligible impact'' on the affected ``species or stocks'' 
of marine mammals. NMFS' and U.S. Fish and Wildlife Service's 
implementing regulations for section 101(a)(5) both define ``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 and 50 CFR 18.27(c)). 
Recruitment (i.e., reproduction) and survival rates are used to 
determine population growth rates \2\ and, therefore are considered in 
evaluating population level impacts.
---------------------------------------------------------------------------

    \2\ A growth rate can be positive, negative, or flat.
---------------------------------------------------------------------------

    As stated in the preamble to the proposed rule for the MMPA 
incidental take implementing regulations, not every population-level 
impact violates the negligible impact requirement. The negligible 
impact standard does not require a finding that the anticipated take 
will have ``no effect'' on population numbers or growth rates: The 
statutory standard does not require that the same recovery rate be 
maintained, rather that no significant effect on annual rates of 
recruitment or survival occurs. The key factor is the significance of 
the level of impact on rates of recruitment or survival. (54 FR 40338, 
40341-42; September 29, 1989).
    While some level of impact on population numbers or growth rates of 
a species or stock may occur and still satisfy the negligible impact 
requirement--even without consideration of mitigation--the least 
practicable adverse impact provision separately requires NMFS to 
prescribe 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, 50 CFR 
216.102(b), which are typically identified as mitigation measures.\3\
---------------------------------------------------------------------------

    \3\ Separately, NMFS also must prescribe means of effecting the 
least practicable adverse impact on the availability of the species 
or stocks for subsistence uses, when applicable. See the Subsistence 
Harvest of Marine Mammals section for separate discussion of the 
effects of the specified activities on Alaska Native subsistence 
use.
---------------------------------------------------------------------------

    The negligible impact and least practicable adverse impact 
standards in the MMPA both call for evaluation at the level of the 
``species or stock.'' The MMPA does not define the term ``species.'' 
However, Merriam-Webster Dictionary defines ``species'' to include 
``related organisms or populations potentially capable of 
interbreeding.'' See www.merriam-webster.com/dictionary/species 
(emphasis added). Section 3(11) of the MMPA defines ``stock'' as a 
group of marine mammals of the same species or smaller taxa in a common 
spatial arrangement that interbreed when mature. The definition of 
``population'' is a group of interbreeding organisms that represents 
the level of organization at which speciation begins. www.merriam-webster.com/dictionary/population. The definition of ``population'' is 
strikingly similar to the MMPA's definition of ``stock,'' with both 
involving groups of individuals that belong to the same species and 
located in a manner that allows for interbreeding. In fact under MMPA 
section 3(11), the term ``stock'' in the MMPA is interchangeable with 
the statutory term ``population stock.'' Both the negligible impact 
standard and the least practicable adverse impact standard call for 
evaluation at the level of the species or stock, and the terms 
``species'' and ``stock'' both relate to populations; therefore, it is 
appropriate to view both the negligible impact standard and the least 
practicable adverse impact standard as having a population-level focus.
    This interpretation is consistent with Congress' statutory findings 
for enacting the MMPA, nearly all of which are most applicable at the 
species or stock (i.e., population) level. See MMPA section 2 (finding 
that it is species and population stocks that are or may be in danger 
of extinction or depletion; that it is species and population stocks 
that should not diminish beyond being significant functioning elements 
of their ecosystems; and that it is species and population stocks that 
should not be permitted to diminish below their optimum sustainable 
population level). Annual rates of recruitment (i.e., reproduction) and 
survival are the key biological metrics used in the evaluation of 
population-level impacts, and accordingly these same metrics are also 
used in the evaluation of population level impacts for the least 
practicable adverse impact standard.
    Recognizing this common focus of the least practicable adverse 
impact and negligible impact provisions on the ``species or stock'' 
does not mean we conflate the two standards; despite some common 
statutory language, we recognize the two provisions are different and 
have different functions. First, a negligible impact finding is 
required before NMFS can issue an incidental take authorization. 
Although it is acceptable to use the mitigation measures to reach a 
negligible impact finding (see 50 CFR 216.104(c)), no amount of 
mitigation can enable NMFS to issue an incidental take authorization 
for an activity that still would not meet the negligible impact 
standard. Moreover, even where NMFS can reach a negligible impact 
finding--which we emphasize does allow for the possibility of some 
``negligible'' population-level impact--the agency must still prescribe 
measures that will effect the least practicable amount of adverse 
impact upon the affected species or stocks.
    Section 101(a)(5)(A)(i)(II) requires NMFS to issue, in conjunction 
with its authorization, binding--and enforceable--restrictions (in the 
form of regulations) setting forth how the activity must be conducted, 
thus ensuring the activity has the ``least practicable adverse impact'' 
on the affected species or stocks. In situations where mitigation is 
specifically needed to reach a negligible impact determination, section 
101(a)(5)(A)(i)(II) also provides a mechanism for ensuring compliance 
with the ``negligible impact'' requirement. Finally, the least 
practicable adverse impact standard also requires consideration of 
measures for marine mammal habitat, with particular attention to 
rookeries, mating grounds, and other areas of similar significance, and 
for subsistence impacts, whereas the negligible impact standard is 
concerned solely with conclusions about the impact of an activity on 
annual rates of recruitment and

[[Page 653]]

survival.\4\ In NRDC v. Pritzker, the Court stated, ``[t]he statute is 
properly read to mean that even if population levels are not threatened 
significantly, still the agency must adopt mitigation measures aimed at 
protecting marine mammals to the greatest extent practicable in light 
of military readiness needs.'' Pritzker at 1134 (emphases added). This 
statement is consistent with our understanding stated above that even 
when the effects of an action satisfy the negligible impact standard 
(i.e., in the Court's words, ``population levels are not threatened 
significantly''), still the agency must prescribe mitigation under the 
least practicable adverse impact standard. However, as the statute 
indicates, the focus of both standards is ultimately the impact on the 
affected ``species or stock,'' and not solely focused on or directed at 
the impact on individual marine mammals.
---------------------------------------------------------------------------

    \4\ Outside of the military readiness context, mitigation may 
also be appropriate to ensure compliance with the ``small numbers'' 
language in MMPA sections 101(a)(5)(A) and (D).
---------------------------------------------------------------------------

    We have carefully reviewed and considered the Ninth Circuit's 
opinion in NRDC v. Pritzker in its entirety. While the Court's 
reference to ``marine mammals'' rather than ``marine mammal species or 
stocks'' in the italicized language above might be construed as holding 
that the least practicable adverse impact standard applies at the 
individual ``marine mammal'' level, i.e., that NMFS must require 
mitigation to minimize impacts to each individual marine mammal unless 
impracticable, we believe such an interpretation reflects an incomplete 
appreciation of the Court's holding. In our view, the opinion as a 
whole turned on the Court's determination that NMFS had not given 
separate and independent meaning to the least practicable adverse 
impact standard apart from the negligible impact standard, and further, 
that the Court's use of the term ``marine mammals'' was not addressing 
the question of whether the standard applies to individual animals as 
opposed to the species or stock as a whole. We recognize that while 
consideration of mitigation can play a role in a negligible impact 
determination, consideration of mitigation measures extends beyond that 
analysis. In evaluating what mitigation measures are appropriate, NMFS 
considers the potential impacts of the specified activities, the 
availability of measures to minimize those potential impacts, and the 
practicability of implementing those measures, as we describe below.

Implementation of Least Practicable Adverse Impact Standard

    Given the NRDC v. Pritzker decision, we discuss here 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 Navy's activities meets the 
``negligible impact'' standard appears in the 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, and 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 measures for applicant 
implementation. Practicability of implementation may consider such 
things as cost, impact on the specified 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 (when evaluating measures to reduce adverse 
impact on the species or stocks).
Evaluation of Measures for Least Practicable Adverse Impact on Species 
or Stocks
    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 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 and national security), 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

[[Page 654]]

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.\5\ 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.
---------------------------------------------------------------------------

    \5\ We recognize the least practicable adverse impact standard 
requires consideration of measures that will address minimizing 
impacts on the availability of the species or stocks for subsistence 
uses where relevant. Because subsistence uses are not implicated for 
this action, we do not discuss them. However, a similar framework 
would apply for evaluating such measures, taking into account the 
MMPA's directive that we also make a finding of no unmitigable 
adverse impact on the availability of the species or stocks for 
taking for subsistence, and the relevant implementing regulations.
---------------------------------------------------------------------------

    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 
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 or 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 GOA Study Area

    Section 216.104(a)(11) of NMFS' implementing regulations requires 
an applicant for incidental take authorization to include in its 
request, among other things, ``the availability and feasibility 
(economic and technological) of equipment, methods, and manner of 
conducting such activity or other means of effecting the least 
practicable adverse impact upon the affected species or stocks, their 
habitat, and [where applicable] on their availability for subsistence 
uses, paying particular attention to rookeries, mating grounds, and 
areas of similar significance.'' Thus NMFS' analysis of the sufficiency 
and appropriateness of an applicant's measures under the least 
practicable adverse impact standard will always begin with evaluation 
of the mitigation measures presented in the application.
    NMFS has fully reviewed the specified activities together with the 
mitigation measures included in the Navy's rulemaking/LOA application 
and the 2022 GOA FSEIS/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 Navy in the development of the 
Navy's initially proposed measures, which are informed by years of 
implementation and monitoring. A complete discussion of the Navy's 
evaluation process used to develop, assess, and select mitigation 
measures, which was informed by input from NMFS, can be found in 
Section 5 (Mitigation) of the 2022 GOA FSEIS/OEIS. The process 
described in Chapter 5 (Mitigation) of the 2022 GOA FSEIS/OEIS robustly 
supported NMFS' independent evaluation of whether the mitigation 
measures meet the least practicable adverse impact standard.
    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 Navy has agreed to procedural mitigation measures that 
will reduce the probability and/or severity of impacts expected to 
result

[[Page 655]]

from acute exposure to acoustic sources and explosives, such as hearing 
impairment, more severe behavioral disturbance, as well as the 
probability of vessel strike. Specifically, the Navy will use a 
combination of delayed starts, powerdowns, and shutdowns to avoid or 
minimize mortality or serious injury, minimize the likelihood or 
severity of PTS or other injury, and reduce instances of TTS or more 
severe behavioral disturbance caused by acoustic sources or explosives. 
The Navy will also implement multiple time/area restrictions that will 
reduce take of marine mammals (as well as impacts on marine mammal 
habitat) in areas where or at times when they are known to engage in 
important behaviors, such as feeding, 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 Navy assessed the practicability of these measures in the 
context of personnel safety, practicality of implementation, and their 
impacts on the Navy's ability to meet their Title 10 requirements and 
found that the measures are supportable. NMFS has independently 
evaluated the measures the Navy 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 will significantly and adequately reduce impacts on the 
affected marine mammal species and stocks and their habitat and, 
further, be practicable for Navy implementation. Therefore, the 
mitigation measures assure that the Navy's activities will have the 
least practicable adverse impact on the species or stocks and their 
habitat.

Measures Evaluated But Not Included

    The Navy also evaluated numerous measures in the 2022 GOA FSEIS/
OEIS that were not included in the Navy's rulemaking/LOA application, 
and NMFS independently reviewed and concurs with the Navy's analysis 
that their inclusion was not appropriate under the least practicable 
adverse impact standard based on our assessment. The Navy considered 
these additional potential mitigation measures in two groups. First, 
Section 5 (Mitigation) of the 2022 GOA FSEIS/OEIS, in the Measures 
Considered but Eliminated section, 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. As described in 
Chapter 5 (Mitigation) of the 2022 GOA FSEIS/OEIS, the Navy considered 
reducing its overall amount of training, reducing explosive use, 
modifying its 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 Section 5 
(Mitigation) of the 2022 GOA FSEIS/OEIS, the Navy needs to train and 
test in the conditions in which it fights--and these types of 
modifications fundamentally change the activity in a manner that will 
not support the purpose and need for the training (i.e., are entirely 
impracticable) and therefore are not considered further. NMFS finds the 
Navy's explanation for why adoption of these recommendations would 
unacceptably undermine the purpose of the training persuasive. After 
independent review, NMFS finds the Navy's judgment on the impacts of 
potential mitigation measures to personnel safety, practicality of 
implementation, and the effectiveness of training to be persuasive, and 
for these reasons, NMFS finds that these measures do not meet the least 
practicable adverse impact standard because they are not practicable 
for implementation in either the TMAA or the GOA Study Area overall.
    Second, in Chapter 5 (Mitigation) of the 2022 GOA FSEIS/OEIS, the 
Navy evaluated additional potential procedural 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 Navy's analysis, the measures would have significant direct 
negative effects on mission effectiveness and are considered 
impracticable (see Section 5 Mitigation of 2022 GOA FSEIS/OEIS). NMFS 
independently reviewed the Navy's evaluation and concurs with this 
assessment, which supports NMFS' 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 2022 GOA FSEIS/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 that area for training, considering proximity to 
training ranges and emergency landing fields and other issues). The 
Navy found that geographic mitigation beyond what is included in the 
2022 GOA FSEIS/OEIS was not warranted because the anticipated reduction 
of adverse impacts on marine mammal species and their habitat was not 
sufficient to offset the impracticability of implementation. 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 Navy's analysis in Chapter 5 (Mitigation) of 
the 2022 GOA FSEIS/OEIS, which considers 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 
including any of the measures that the Navy ruled out in the 2022 GOA 
FSEIS/OEIS.
    The following sections describe the mitigation measures that will 
be implemented in association with the training activities analyzed in 
this document. These are the mitigation measures that NMFS has 
determined will ensure the least practicable adverse impact on all 
affected species and their habitat, including the specific 
considerations for military readiness activities. The mitigation 
measures are organized into two categories: procedural mitigation and 
mitigation areas.

Procedural Mitigation

    Procedural mitigation is mitigation that the Navy will implement 
whenever and wherever an applicable training activity takes place 
within the GOA Study Area. Procedural mitigation is customized for each 
applicable activity category or stressor. Procedural mitigation 
generally involves: (1) the use of one or more trained Lookouts to 
diligently observe for specific biological resources (including marine 
mammals)

[[Page 656]]

within a mitigation zone, (2) requirements for Lookouts to immediately 
communicate sightings of these 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 
first procedural mitigation (Table 33) is designed to aid Lookouts and 
other applicable Navy personnel in their observation, environmental 
compliance, and reporting responsibilities. The remainder of the 
procedural mitigation measures (Table 34 through Table 41) are 
organized by stressor type and activity category and include acoustic 
stressors (i.e., active sonar, weapons firing noise), explosive 
stressors (i.e., large-caliber projectiles, bombs), 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 bombs).

     Table 33--Procedural Mitigation for Environmental Awareness and
                                Education
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
     All training activities, as applicable.
Mitigation Requirements:
     Appropriate Navy personnel (including civilian personnel)
     involved in mitigation and training activity reporting under the
     specified activities will 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 the U.S. Navy Afloat Environmental Compliance
         Training Series. The introductory module provides information
         on environmental laws (e.g., Endangered Species Act, Marine
         Mammal Protection Act) and the corresponding responsibilities
         that are relevant to Navy training activities. The material
         explains why environmental compliance is important in
         supporting the Navy's commitment to environmental stewardship.
        --Marine Species Awareness Training. All bridge watch personnel,
         Commanding Officers, Executive Officers, maritime patrol
         aircraft aircrews, anti[hyphen]submarine warfare 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.
        --U.S. Navy 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 software tool.
        --U.S. Navy 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.
------------------------------------------------------------------------

Procedural Mitigation for Acoustic Stressors
    Mitigation measures for acoustic stressors are provided in Table 34 
and Table 35.

            Table 34--Procedural Mitigation for Active Sonar
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
     Mid-frequency active sonar and high-frequency
     active sonar:
        --For vessel-based active sonar activities, mitigation applies
         only to sources that are positively controlled and deployed
         from manned surface vessels (e.g., sonar sources towed from
         manned surface platforms).
        --For aircraft-based active sonar activities, mitigation applies
         only to sources that are positively controlled and deployed
         from manned aircraft that do not operate at high altitudes
         (e.g., rotary-wing aircraft). Mitigation does not apply to
         active sonar sources deployed from unmanned aircraft or
         aircraft operating at high altitudes (e.g., maritime patrol
         aircraft).
Number of Lookouts and Observation Platform:
     Hull-mounted sources:
        --1 Lookout: Platforms with space or manning restrictions while
         underway (at the forward part of a small boat or ship) and
         platforms using active sonar while moored or at anchor.
        --2 Lookouts: Platforms without space or manning restrictions
         while underway (at the forward part of the ship).
     Sources that are not hull-mounted:
        --Lookout on the ship or aircraft conducting the activity.
Mitigation Requirements:
     Mitigation zones:
        --1,000 yd (914.4 m) power down, 500 yd (457.2 m) power down,
         and 200 yd (182.9 m) shut down for hull-mounted mid-frequency
         active sonar (see During the activity below).
        --200 yd (182.9 m) shut down for mid-frequency active sonar
         sources that are not hull-mounted, and high-frequency active
         sonar (see During the activity below).
     Prior to the initial start of the activity (e.g., when
     maneuvering on station):
        --Navy personnel will observe the mitigation zone for floating
         vegetation and marine mammals; if floating vegetation or a
         marine mammal is observed, Navy personnel will relocate or
         delay the start of active sonar transmission until the
         mitigation zone is clear of floating vegetation or the
         Commencement/recommencement conditions in this table are met
         for marine mammals.
     During the activity:

[[Page 657]]

 
        --Hull-mounted mid-frequency active sonar: Navy personnel will
         observe the mitigation zone for marine mammals; Navy personnel
         will power down active sonar transmission by 6 dB if a marine
         mammal is observed within 1,000 yd (914.4 m) of the sonar
         source; Navy personnel will power down active sonar
         transmission an additional 4 dB (10 dB total) if a marine
         mammal is observed within 500 yd (457.2 m) of the sonar source;
         Navy personnel will cease transmission if a marine mammal is
         observed within 200 yd (182.9 m) of the sonar source.
        --Mid-frequency active sonar sources that are not hull-mounted,
         and high-frequency active sonar: Navy personnel will observe
         the mitigation zone for marine mammals; Navy personnel will
         cease transmission if a marine mammal is observed within 200 yd
         (182.9 m) of the sonar source.
     Commencement/recommencement conditions after a marine
     mammal sighting before or during the activity:
        --Navy personnel will allow a sighted marine mammal to leave the
         mitigation zone 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) until one of the
         following conditions has been met: (1) the animal is observed
         exiting the mitigation zone; (2) the animal is thought to have
         exited the mitigation zone based on a determination of its
         course, speed, and movement relative to the sonar source; (3)
         the mitigation zone has been clear from any additional
         sightings for 10 minutes for aircraft-deployed sonar sources or
         30 minutes for vessel-deployed sonar sources; (4) for mobile
         activities, the active sonar source has transited a distance
         equal to double that of the mitigation zone size beyond the
         location of the last sighting; or (5) for activities using hull-
         mounted sonar, the Lookout concludes that dolphins are
         deliberately closing in on the ship to ride the ship's bow
         wave, and are therefore out of the main transmission axis of
         the sonar (and there are no other marine mammal sightings
         within the mitigation zone).
------------------------------------------------------------------------


        Table 35--Procedural Mitigation for Weapons Firing Noise
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
     Weapon firing noise associated with large-caliber gunnery
     activities.
Number of Lookouts and Observation Platform:
     1 Lookout positioned on the ship conducting the firing.
        --Depending on the activity, the Lookout could be the same one
         described in Procedural Mitigation for Explosive Large-Caliber
         Projectiles (Table 36) or Procedural Mitigation for Small-,
         Medium-, and Large-Caliber Non-Explosive Practice Munitions
         (Table 40).
Mitigation Requirements:
     Mitigation zone:
        --30[deg] on either side of the firing line out to 70 yd (64 m)
         from the muzzle of the weapon being fired.
     Prior to the initial start of the activity:
        --Navy personnel will observe the mitigation zone for floating
         vegetation and marine mammals; if floating vegetation or a
         marine mammal is observed, Navy personnel will relocate or
         delay the start of weapon firing until the mitigation zone is
         clear of floating vegetation or the Commencement/recommencement
         conditions in this table are met for marine mammals.
     During the activity:
        --Navy personnel will observe the mitigation zone for marine
         mammals; if a marine mammal is observed, Navy personnel will
         cease weapon firing.
     Commencement/recommencement conditions after a marine
     mammal sighting before or during the activity:
        --Navy personnel will allow a sighted marine mammal to leave the
         mitigation zone prior to the initial start of the activity (by
         delaying the start) or during the activity (by not recommencing
         weapon firing) until one of the following conditions has been
         met: (1) the animal is observed exiting the mitigation zone;
         (2) the animal is thought to have exited the mitigation zone
         based on a determination of its course, speed, and movement
         relative to the firing ship; (3) the mitigation zone has been
         clear from any additional sightings for 30 minutes; or (4) for
         mobile activities, the firing ship has transited a distance
         equal to double that of the mitigation zone size beyond the
         location of the last sighting.
------------------------------------------------------------------------

Procedural Mitigation for Explosive Stressors
    Mitigation measures for explosive stressors are provided in Table 
36 and Table 37.

 Table 36--Procedural Mitigation for Explosive Large-Caliber Projectiles
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
     Gunnery activities using explosive large-caliber
     projectiles.
        --Mitigation applies to activities using a surface target.
Number of Lookouts and Observation Platform:
     1 Lookout on the vessel or aircraft conducting the
     activity.
        --Depending on the activity, the Lookout could be the same as
         the one described for Procedural Mitigation for Weapons Firing
         Noise in Table 35.
     If additional platforms are participating in the activity,
     Navy personnel positioned in those assets (e.g., safety observers,
     evaluators) will support observing the mitigation zone for marine
     mammals while performing their regular duties.
Mitigation Requirements:
     Mitigation zones:

[[Page 658]]

 
        --1,000 yd (914.4 m) around the intended impact location.
     Prior to the initial start of the activity (e.g., when
     maneuvering on station):
        --Navy personnel will observe the mitigation zone for floating
         vegetation and marine mammals; if floating vegetation or a
         marine mammal is observed, Navy personnel will relocate or
         delay the start of firing until the mitigation zone is clear of
         floating vegetation or the Commencement/recommencement
         conditions in this table are met for marine mammals.
     During the activity:
        --Navy personnel will observe the mitigation zone for marine
         mammals; if a marine mammal is observed, Navy personnel will
         cease firing.
     Commencement/recommencement conditions after a marine
     mammal sighting before or during the activity:
        --Navy personnel will allow a sighted marine mammal to leave the
         mitigation zone prior to the initial start of the activity (by
         delaying the start) or during the activity (by not recommencing
         firing) until one of the following conditions has been met: (1)
         the animal is observed exiting the mitigation zone; (2) the
         animal is thought to have exited the mitigation zone based on a
         determination of its course, speed, and movement relative to
         the intended impact location; (3) the mitigation zone has been
         clear from any additional sightings for 30 minutes; or (4) for
         activities using mobile targets, the intended impact location
         has transited a distance equal to double that of the mitigation
         zone size beyond the location of the last sighting.
     After completion of the activity (e.g., prior to
     maneuvering off station):
        --Navy personnel will, when practical (e.g., when platforms are
         not constrained by fuel restrictions or mission-essential
         follow-on commitments), observe the vicinity of where
         detonations occurred; if any injured or dead marine mammals are
         observed, Navy personnel will follow established incident
         reporting procedures.
        --If additional platforms are supporting this activity (e.g.,
         providing range clearance), Navy personnel positioned on these
         assets will assist in the visual observation of the area where
         detonations occurred.
------------------------------------------------------------------------


           Table 37--Procedural Mitigation for Explosive Bombs
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
     Explosive bombs.
Number of Lookouts and Observation Platform:
     1 Lookout positioned in the aircraft conducting the
     activity.
     If additional platforms are participating in the activity,
     Navy personnel positioned in those assets (e.g., safety observers,
     evaluators) will support observing the mitigation zone for marine
     mammals while performing their regular duties.
Mitigation Requirements:
     Mitigation zone:
        --2,500 yd (2,286 m) around the intended target.
     Prior to the initial start of the activity (e.g., when
     arriving on station):
        --Navy personnel will observe the mitigation zone for floating
         vegetation and marine mammals; if floating vegetation or a
         marine mammal is observed, Navy personnel will relocate or
         delay the start of bomb deployment until the mitigation zone is
         clear of floating vegetation or the Commencement/recommencement
         conditions in this table are met for marine mammals.
     During the activity (e.g., during target approach):
        --Navy personnel will observe the mitigation zone for marine
         mammals; if a marine mammal is observed, Navy personnel will
         cease bomb deployment.
     Commencement/recommencement conditions after a marine
     mammal sighting before or during the activity:
        --Navy personnel will allow a sighted marine mammal to leave the
         mitigation zone prior to the initial start of the activity (by
         delaying the start) or during the activity (by not recommencing
         bomb deployment) until one of the following conditions has been
         met: (1) the animal is observed exiting the mitigation zone;
         (2) the animal is thought to have exited the mitigation zone
         based on a determination of its course, speed, and movement
         relative to the intended target; (3) the mitigation zone has
         been clear from any additional sightings for 10 minutes; or (4)
         for activities using mobile targets, the intended target has
         transited a distance equal to double that of the mitigation
         zone size beyond the location of the last sighting.
     After completion of the activity (e.g., prior to
     maneuvering off station):
        --Navy personnel will, when practical (e.g., when platforms are
         not constrained by fuel restrictions or mission-essential
         follow-on commitments), observe for marine mammals in the
         vicinity of where detonations occurred; if any injured or dead
         marine mammals are observed, Navy personnel will follow
         established incident reporting procedures.
        --If additional platforms are supporting this activity (e.g.,
         providing range clearance), Navy personnel positioned on these
         assets will assist in the visual observation of the area where
         detonations occurred.
------------------------------------------------------------------------

Procedural Mitigation for Physical Disturbance and Strike Stressors
    Mitigation measures for physical disturbance and strike stressors 
are provided in Table 38 through Table 41.

           Table 38--Procedural Mitigation for Vessel Movement
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
     Vessel movement:

[[Page 659]]

 
        --The mitigation will not be applied if (1) the vessel's safety
         is threatened, (2) the vessel is restricted in its ability to
         maneuver (e.g., during launching and recovery of aircraft or
         landing craft, during towing activities, when mooring), (3) the
         vessel is submerged or operated autonomously, or (4) when
         impractical based on mission requirements (e.g., during Vessel
         Visit, Board, Search, and Seizure activities as military
         personnel from ships or aircraft board suspect vessels).
Number of Lookouts and Observation Platform:
     1 or more Lookouts on the underway vessel \1\
     If additional watch personnel are positioned on underway
     vessels, those personnel (e.g., persons assisting with navigation
     or safety) will support observing for marine mammals while
     performing their regular duties.
Mitigation Requirements:
     Mitigation zones:
        --500 yd (457.2 m) around the vessel for whales.
        --200 yd (182.9 m) around the vessel for marine mammals other
         than whales (except those intentionally swimming alongside or
         closing in to swim alongside vessels, such as bow-riding or
         wake-riding dolphins).
     When Underway:
        --Navy personnel will observe the direct path of the vessel and
         waters surrounding the vessel for marine mammals.
        --If a marine mammal is observed in the direct path of the
         vessel, Navy personnel will maneuver the vessel as necessary to
         maintain the appropriate mitigation zone distance.
        --If a marine mammal is observed within waters surrounding the
         vessel, Navy personnel will maintain situational awareness of
         that animal's position. Based on the animal's course and speed
         relative to the vessel's path, Navy personnel will maneuver the
         vessel as necessary to ensure that the appropriate mitigation
         zone distance from the animal continues to be maintained.
     Additional requirements:
        --If a marine mammal vessel strike occurs, Navy personnel will
         follow established incident reporting procedures.
------------------------------------------------------------------------
\1\ Underway vessels will maintain at least one Lookout. Navy policy
  currently requires some ship classes to maintain more than one
  Lookout. The requirement to maintain additional Lookouts is subject to
  change over time in accordance with Navy navigation instruction.


       Table 39--Procedural Mitigation for Towed In-Water Devices
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
     Towed in-water devices:
        --Mitigation applies to devices that are towed from a manned
         surface platform or manned aircraft, or when a manned support
         craft is already participating in an activity involving in-
         water devices being towed by unmanned platforms.
        --The mitigation will not be applied if the safety of the towing
         platform or in-water device is threatened.
Number of Lookouts and Observation Platform:
     1 Lookout positioned on the towing platform or support
     craft.
Mitigation Requirements:
     Mitigation zones:
        --250 yd (228.6 m) around the towed in-water device for marine
         mammals (except those intentionally swimming alongside or
         choosing to swim alongside towing vessels, such as bow-riding
         or wake-riding dolphins).
     During the activity (i.e., when towing an in-water device):
        --Navy personnel will observe the mitigation zone for marine
         mammals; if a marine mammal is observed, Navy personnel will
         maneuver to maintain distance.
------------------------------------------------------------------------


 Table 40--Procedural Mitigation for Small-, Medium-, and Large-Caliber
                    Non-Explosive Practice Munitions
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
     Gunnery activities using small-, medium-, and large-caliber
     non-explosive practice munitions:
        --Mitigation applies to activities using a surface target.
Number of Lookouts and Observation Platform:
     1 Lookout positioned on the platform conducting the
     activity.
        --Depending on the activity, the Lookout could be the same as
         the one described in Procedural Mitigation for Weapons Firing
         Noise (Table 35).
Mitigation Requirements:
     Mitigation zone:
        --200 yd (182.9 m) around the intended impact location.
     Prior to the initial start of the activity (e.g., when
     maneuvering on station):
        --Navy personnel will observe the mitigation zone for floating
         vegetation and marine mammals; if floating vegetation or a
         marine mammal is observed, Navy personnel will relocate or
         delay the start of firing until the mitigation zone is clear of
         floating vegetation or the Commencement/recommencement
         conditions in this table are met for marine mammals.
     During the activity:
        --Navy personnel will observe the mitigation zone for marine
         mammals; if a marine mammal is observed, Navy personnel will
         cease firing.
     Commencement/recommencement conditions after a marine
     mammal, sighting before or during the activity:

[[Page 660]]

 
        --Navy personnel will allow a sighted marine mammal to leave the
         mitigation zone prior to the initial start of the activity (by
         delaying the start) or during the activity (by not recommencing
         firing) until one of the following conditions has been met: (1)
         the animal is observed exiting the mitigation zone; (2) the
         animal is thought to have exited the mitigation zone based on a
         determination of its course, speed, and movement relative to
         the intended impact location; (3) the mitigation zone has been
         clear from any additional sightings for 10 minutes for aircraft-
         based firing or 30 minutes for vessel-based firing; or (4) for
         activities using a mobile target, the intended impact location
         has transited a distance equal to double that of the mitigation
         zone size beyond the location of the last sighting.
------------------------------------------------------------------------


         Table 41--Procedural Mitigation for Non-Explosive Bombs
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
     Non-explosive bombs.
Number of Lookouts and Observation Platform:
     1 Lookout positioned in an aircraft.
Mitigation Requirements
     Mitigation zone:
        --1,000 yd (914.4 m) around the intended target.
     Prior to the initial start of the activity (e.g., when
     arriving on station):
        --Navy personnel will observe the mitigation zone for floating
         vegetation and marine mammals; if floating vegetation or a
         marine mammal is observed, Navy personnel will relocate or
         delay the start of bomb deployment until the mitigation zone is
         clear of floating vegetation or the Commencement/recommencement
         conditions in this table are met for marine mammals.
     During the activity (e.g., during approach of the target):
        --Navy personnel will observe the mitigation zone for marine
         mammals; if a marine mammal is observed, Navy personnel will
         cease bomb deployment.
     Commencement/recommencement conditions after a marine
     mammal sighting prior to or during the activity:
        --Navy personnel will allow a sighted marine mammal to leave the
         mitigation zone prior to the initial start of the activity (by
         delaying the start) or during the activity (by not recommencing
         bomb deployment) until one of the following conditions has been
         met: (1) the animal is observed exiting the mitigation zone;
         (2) the animal is thought to have exited the mitigation zone
         based on a determination of its course, speed, and movement
         relative to the intended target; (3) the mitigation zone has
         been clear from any additional sightings for 10 minutes; or (4)
         for activities using mobile targets, the intended target has
         transited a distance equal to double that of the mitigation
         zone size beyond the location of the last sighting.
------------------------------------------------------------------------

Mitigation Areas

    In addition to procedural mitigation, the Navy will implement 
mitigation measures within mitigation areas to avoid or minimize 
potential impacts on marine mammals. NMFS and the Navy took into 
account public comments received on the 2020 GOA DSEIS/OEIS, 2022 
Supplement to the 2020 GOA DSEIS/OEIS, and the 2022 GOA proposed rule, 
best available science, and the practicability of implementing 
additional mitigation measures and has enhanced the mitigation measures 
beyond the 2017-2022 regulations, to further reduce impacts to marine 
mammals. Of note specifically, as noted in the preamble to the 2017-
2022 regulations (82 FR 19530; April 27, 2017), the Navy committed 
during that rulemaking to mitigation that precluded the use of 
explosives in the Portlock Bank area. In this rule, this mitigation has 
been expanded into the Continental Shelf and Slope Mitigation Area, as 
described in further detail below.
    Descriptions of the mitigation measures that the Navy will 
implement within mitigation areas is provided in Table 42 (see below).
    NMFS conducted an independent analysis of the mitigation areas that 
the Navy will implement and that are included in this rule. NMFS' 
analysis indicates that the measures in these mitigation areas will 
reduce the likelihood or severity of adverse impacts to marine mammal 
species or their habitat in the manner described in this rule and are 
practicable for the Navy.
    Specifically, below we describe how certain activities are limited 
in feeding areas, migratory corridors, or other important habitat. To 
avoid repetition in those sections, we describe here how these measures 
reduce the likelihood or severity of effects on marine mammals and 
their habitat. As described previously, exposure to active sonar and 
explosive detonations (in-air, occurring at or above the water surface) 
has the potential to both disrupt behavioral patterns and reduce 
hearing sensitivity (temporarily or permanently, depending on the 
intensity and duration of the exposure). Disruption of feeding 
behaviors can have negative energetic consequences as a result of 
either obtaining less food in a given time or expending more energy (in 
the effort to avoid the stressor) to find the necessary food elsewhere, 
and extensive disruptions of this sort (especially over multiple 
sequential days) could accumulate in a manner that could negatively 
impact reproductive success or survival (though no impacts to 
reproductive success or survival are anticipated to occur as a result 
of the specified activity). By limiting impacts in known feeding areas, 
the overall severity of any take in those areas is reduced and the 
likelihood of impacts on reproduction or survival is further lessened. 
Similarly, reducing impacts on prey species, either by avoiding causing 
mortality or changing their expected distribution, can also lessen 
these sorts of detrimental energetic consequences. In migratory 
corridors, training activities can result in additional energetic 
expenditures to avoid the loud sources--lessening training in these 
areas also reduces the likelihood of detrimental energetic effects. In 
all of the mitigation areas, inasmuch as the density of certain species 
may be higher at certain times, a selective reduction of training 
activities in those higher-density areas

[[Page 661]]

and times is expected to lessen the magnitude of take overall, as well 
as the specific likelihood of hearing impairment.
    Regarding operational practicability, NMFS is heavily reliant on 
the Navy's description and conclusions, since the Navy is best equipped 
to describe the degree to which a given mitigation measure affects 
personnel safety or mission effectiveness and is practical to 
implement. The Navy considers the measures in this rule to be 
practicable, and NMFS concurs.

   Table 42--Geographic Mitigation Areas for Marine Mammals in the GOA
                               Study Area
------------------------------------------------------------------------
                       Mitigation area description
-------------------------------------------------------------------------
Stressor or Activity:
     Sonar.
     Explosives.
     Physical disturbance and strikes.
Mitigation Requirements \1\:
     North Pacific Right Whale Mitigation Area.
        --From June 1-September 30 within the North Pacific Right Whale
         Mitigation Area, Navy personnel will not use surface ship hull-
         mounted MF1 mid-frequency active sonar during training.
     Continental Shelf and Slope Mitigation Area.
        --During training, Navy personnel will not detonate explosives
         below 10,000 ft. altitude (including at the water surface) in
         the Continental Shelf and Slope Mitigation Area, which extends
         over the continental shelf and slope out to the 4,000 m depth
         contour within the TMAA.
     Pre-event Awareness Notifications in the Temporary Maritime
     Activities Area.
        --The Navy will issue pre-event awareness messages to alert
         vessels and aircraft participating in training activities
         within the TMAA to the possible presence of concentrations of
         large whales on the continental shelf and slope. Occurrences of
         large whales may be higher over the continental shelf and slope
         relative to other areas of the TMAA. Large whale species in the
         TMAA include, but are not limited to, fin whale, blue whale,
         humpback whale, gray whale, North Pacific right whale, sei
         whale, and sperm whale. To maintain safety of navigation and to
         avoid interactions with marine mammals, the Navy will instruct
         personnel to remain vigilant to the presence of large whales
         that may be vulnerable to vessel strikes or potential impacts
         from training activities. Additionally, Navy personnel will use
         the information from the awareness notification messages to
         assist their visual observation of applicable mitigation zones
         during training activities and to aid in the implementation of
         procedural mitigation.
------------------------------------------------------------------------
\1\ Should national security present a requirement to conduct training
  prohibited by the mitigation requirements specified in this table,
  naval units will obtain permission from the designated Command, U.S.
  Third Fleet Command Authority, prior to commencement of the activity.
  The Navy will provide NMFS with advance notification and include
  relevant information about the event (e.g., sonar hours, use of
  explosives detonated below 10,000 ft altitude (including at the water
  surface) in its annual activity reports to NMFS).

BILLING CODE 3510-22-P

[[Page 662]]

[GRAPHIC] [TIFF OMITTED] TR04JA23.108

BILLING CODE 3510-22-C

North Pacific Right Whale Mitigation Area

    Mitigation within the North Pacific Right Whale Mitigation Area is 
primarily designed to avoid or further reduce potential impacts to 
North Pacific right whales within important feeding habitat. The 
mitigation area fully encompasses the portion of the BIA identified by 
Ferguson et al. (2015) for North Pacific right whale feeding that 
overlaps the GOA Study Area (overlap between the GOA Study Area and the 
BIA occurs in the TMAA only) (see Figure 2 of the proposed rule; 87 FR 
49656; August 11, 2022). North Pacific right whales are thought to 
occur in the highest densities in the BIA from June to September. The 
Navy will not use surface ship hull-mounted MF1 mid-frequency active 
sonar in the mitigation area from June 1 to September 30, as was also 
required in the Phase II (2017-2022) rule. The North Pacific Right 
Whale Mitigation Area is fully within

[[Page 663]]

the boundary of the Continental Shelf and Slope Mitigation Area, 
discussed below. Therefore, the mitigation requirements in that area 
also apply to the North Pacific Right Whale Mitigation Area. While the 
potential occurrence of North Pacific right whales in the GOA Study 
Area is expected to be rare due to the species' extremely low 
population, these mitigation requirements would help further avoid or 
further reduce the potential for impacts to occur within North Pacific 
right whale feeding habitat, thus likely reducing the number of takes 
of North Pacific right whales, as well as the severity of any 
disturbances by reducing the likelihood that feeding is interrupted, 
delayed, or precluded for some limited amount of time.
    Additionally, the North Pacific Right Whale Mitigation Area 
overlaps with a small portion of the humpback whale critical habitat 
Unit 5, in the southwest corner of the TMAA. While the overlap of the 
two areas is limited, mitigation in the North Pacific Right Whale 
Mitigation Area may reduce the number and/or severity of takes of 
humpback whales in this important area.
    The mitigation in this area will also help avoid or reduce 
potential impacts on fish and invertebrates that inhabit the mitigation 
area and which marine mammals prey upon. As described in Section 
5.4.1.5 (Fisheries Habitats) of the 2022 GOA FSEIS/OEIS, the productive 
waters off Kodiak Island support a strong trophic system from plankton, 
invertebrates, small fish, and higher-level predators, including large 
fish and marine mammals.

Continental Shelf and Slope Mitigation Area

    The Continental Shelf and Slope Mitigation Area encompasses the 
portion of the continental shelf and slope that overlaps the TMAA (the 
entire continental shelf and slope out to the 4,000 m depth contour; 
see Figure 2 of the proposed rule; 87 FR 49656; August 11, 2022). Navy 
personnel will not detonate explosives below 10,000 ft. altitude 
(including at the water surface) in the Continental Shelf and Slope 
Mitigation Area during training. (As stated previously, the Navy does 
not plan to use in-water explosives anywhere in the GOA Study Area.) 
Mitigation in the Continental Shelf and Slope Mitigation Area was 
initially designed to avoid or reduce potential impacts on fishery 
resources for Alaska Natives. However, the area includes highly 
productive waters where marine mammals, including humpback whales 
(Lagerquist et al., 2008) and North Pacific right whales, feed, and 
overlaps with a small portion of the North Pacific right whale feeding 
BIA off of Kodiak Island. Additionally, the Continental Shelf and Slope 
Mitigation Area overlaps with a very small portion of the humpback 
whale critical habitat Unit 5, on the western side of the TMAA, and a 
small portion of humpback whale critical habitat Unit 8 on the north 
side of the TMAA. The Continental Shelf and Slope mitigation area also 
overlaps with a very small portion of the gray whale migration BIA. The 
remainder of the designated critical habitat and BIAs are located 
beyond the boundaries of the GOA Study Area. While the overlap of the 
mitigation area with critical habitat and feeding and migratory BIAs is 
limited, mitigation in the Continental Shelf and Slope Mitigation Area 
may reduce the probability, number, and/or severity of takes of 
humpback whales, North Pacific right whales, and gray whales in this 
important area (noting that the Navy's Acoustic Effects Model estimated 
zero takes for gray whales, though NMFS has conservatively authorized 
four takes by Level B harassment). Additionally, mitigation in this 
area will likely reduce the number and severity of potential impacts to 
marine mammals in general, by reducing the likelihood that feeding is 
interrupted, delayed, or precluded for some limited amount of time.

Pre-Event Awareness Notifications in the Temporary Maritime Activities 
Area

    The Navy will issue awareness messages prior to the start of TMAA 
training activities to alert vessels and aircraft operating within the 
TMAA to the possible presence of concentrations of large whales, 
including but not limited to, fin whale, blue whale, humpback whale, 
gray whales, North Pacific right whale, sei whale, minke whale, and 
sperm whale, especially when traversing on the continental shelf and 
slope where densities of these species may be higher. To maintain 
safety of navigation and to avoid interactions with marine mammals, the 
Navy will instruct vessels to remain vigilant to the presence of large 
whales that may be vulnerable to vessel strikes or potential impacts 
from training activities. Navy personnel will use the information from 
the awareness notification messages to assist their visual observation 
of applicable mitigation zones during training activities and to aid in 
the implementation of procedural mitigation.
    This mitigation will help avoid any potential impacts from vessel 
strikes and training activities on large whales within the TMAA.

Availability for Subsistence Uses

    The nature of subsistence activities by Alaska Natives in the GOA 
Study Area are discussed below, in the Subsistence Harvest of Marine 
Mammals section of this rule.

Mitigation Conclusions

    NMFS has carefully evaluated the mitigation measures--many of which 
were developed with NMFS' input during the previous phases of Navy 
training authorizations but several of which are new since 
implementation of the 2017 to 2022 regulations. NMFS has also 
considered a broad range of other measures (e.g., the measures 
considered but eliminated in the 2022 GOA FSEIS/OEIS, which reflect 
other comments that have arisen via NMFS or public input 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 or stocks 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 or stocks 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 Navy's proposed measures, as well as 
other measures considered by the Navy and NMFS, NMFS has determined 
that the mitigation measures included in this final rule are the 
appropriate means of effecting the least practicable adverse impact on 
marine mammal species or stocks 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 
provision ensures that mitigation is regularly assessed and provides a 
mechanism to improve the mitigation, based on the factors above, 
through modification as appropriate. Thus, NMFS concludes that the 
mitigation measures outlined in this final rule satisfy the statutory 
standard and that any adverse impacts that remain cannot be practicably 
further mitigated.

[[Page 664]]

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 GOA 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, MMPA rules, and ESA 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 Spatial Ecological Analysis 
of Megavertebrate Populations (OBIS-SEAMAP) site (https://seamap.env.duke.edu/).
    The Navy will continue collecting and reporting monitoring data to 
inform our understanding of the occurrence of marine mammals in the GOA 
Study Area; the likely exposure of marine mammals to stressors of 
concern in the GOA 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 Navy 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 resources.

Integrated Comprehensive Monitoring Program (ICMP)

    The Navy's ICMP is intended to coordinate marine species monitoring 
efforts across all regions and to allocate the most appropriate level 
and type of effort for each range complex based on a set of 
standardized objectives, and in acknowledgement of regional expertise 
and resource availability. The ICMP is designed to be flexible, 
scalable, and adaptable through the adaptive management and strategic 
planning processes to periodically assess progress and reevaluate 
objectives. This process includes conducting an annual adaptive 
management review meeting, at which the Navy and NMFS jointly consider 
the prior-year goals, monitoring results, and related scientific 
advances to determine if monitoring plan modifications are warranted to 
more effectively address program goals. Although the ICMP does not 
specify actual monitoring field work or individual projects, it does 
establish a matrix of goals and objectives that have been developed in 
coordination with NMFS. As the ICMP is implemented through the 
Strategic Planning Process (see the section below), detailed and 
specific studies that support the Navy's and NMFS' top-level monitoring 
goals will continue to be developed. In essence, the ICMP directs that 
monitoring activities relating to the effects of Navy training and 
testing activities on marine species should be designed to contribute 
towards one or more of the following top-level goals:
     An increase in the understanding of the likely occurrence 
of marine mammals and/or ESA-listed marine species in the vicinity of 
the action (i.e., presence, abundance, distribution, and density of 
species);
     An increase in the understanding of the nature, scope, or 
context of the likely exposure of marine mammals and/or 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: (1) the 
action and the environment in which it occurs (e.g., sound-source 
characterization, propagation, and ambient noise levels), (2) the 
affected species (e.g., life history or dive patterns), (3) the likely 
co-occurrence of marine mammals and/or ESA-listed marine species with 
the action (in whole or part), and (4) the likely biological or 
behavioral context of exposure to the stressor for the marine mammal 
and/or ESA-listed marine species (e.g., age class of exposed animals or 
known pupping, calving, or feeding areas);
     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);
     An increase in the understanding of how anticipated 
individual responses, to individual stressors or anticipated 
combinations of stressors, may impact either (1) the long-term fitness 
and survival of an individual; or (2) the population, species, or stock 
(e.g., through impacts on annual rates of recruitment or survival);
     An increase in the understanding of the effectiveness of 
mitigation and monitoring measures;
     A better understanding and record of the manner in which 
the Navy complies with the incidental take regulations and LOAs and the 
ESA Incidental Take Statement;
     An increase in the probability of detecting marine mammals 
(through improved technology or methods), both specifically within the 
mitigation zones (thus allowing for more effective implementation of 
the mitigation) and in general, to better achieve the above goals; and
     Ensuring that adverse impact of activities remains at the 
least practicable level.

Strategic Planning Process for Marine Species Monitoring

    The Navy also developed the Strategic Planning Process for Marine 
Species Monitoring, which establishes the guidelines and processes 
necessary to develop, evaluate, and fund individual projects based on 
objective scientific study questions. The process uses an underlying 
framework designed around intermediate scientific objectives and a 
conceptual framework incorporating a progression of knowledge spanning 
occurrence, exposure, response, and consequence. The Strategic Planning 
Process for Marine Species Monitoring is used to set overarching 
intermediate scientific objectives; develop individual monitoring 
project concepts; identify potential species of interest at a regional 
scale; evaluate, prioritize, and select specific monitoring projects to 
fund or continue supporting for a given fiscal year; execute and manage 
selected

[[Page 665]]

monitoring projects; and report and evaluate progress and results. This 
process addresses relative investments to different range complexes 
based on goals across all range complexes, and monitoring leverages 
multiple techniques for data acquisition and analysis whenever 
possible. The Strategic Planning Process for Marine Species Monitoring 
is also available online (https://www.navymarinespeciesmonitoring.us/).

Past and Current Monitoring in the GOA Study Area

    The monitoring program has undergone significant changes since the 
first rule was issued for the TMAA in 2011, which highlights the 
monitoring program's evolution 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, thereby eliminating the previous level-of-effort metrics. 
Furthermore, refinements of scientific objectives have continued 
through the latest authorization cycle.
    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, 
including what is now the GOA Study Area, 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. In the GOA, the Navy conducts three types of 
monitoring: (1) Passive acoustic monitoring (including technologies 
such as stationary moored high-frequency acoustic recording packages or 
non-stationary (i.e., mobile) gliders (e.g., Klinck et al., 2016, Rice 
et al., 2020), (2) visual surveys (e.g., Crance et al., 2022, and Rone 
et al., 2017), and (3) satellite tagging of marine mammals and fish 
(e.g., Palacios et al., 2021, and Seitz and Courtney, 2022).
    Numerous publications, dissertations, and conference presentations 
have resulted from research conducted under the marine species 
monitoring program, including research conducted in what is now the GOA 
Study Area (https://www.navymarinespeciesmonitoring.us/reading-room/publications/), resulting in 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 analyses of behavioral response 
and consideration of mitigation measures.
    Furthermore, collaboration between the monitoring program and the 
Navy's research and development (e.g., the Office of Naval Research) 
and demonstration-validation (e.g., Living Marine Resources) 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 (M3R), controlled exposure experiment 
behavioral response studies (CEE BRS), 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 study areas in the Pacific and the Atlantic 
Oceans, and various other testing ranges. Publications from the Living 
Marine Resources and Office of Naval Research programs have also 
resulted in significant contributions to information on hearing ranges 
and acoustic criteria used in effects modeling, exposure, and response, 
as well as in developing tools to assess biological significance (e.g., 
population-level consequences).
    NMFS and the Navy also consider data collected during procedural 
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 will continue under this 
rule.
    NMFS has received multiple years' worth of annual exercise and 
monitoring reports addressing active sonar use and explosive 
detonations within the TMAA and other Navy range complexes. The data 
and information contained in these reports have been considered in 
developing mitigation and monitoring measures for the training 
activities within the GOA Study Area. The Navy's annual training and 
monitoring reports may be viewed at https://www.navymarinespeciesmonitoring.us/reporting/.
    The Navy's marine species monitoring program typically supports 
monitoring projects in the GOA Study Area. Additional details on the 
scientific objectives for each project can be found at https://www.navymarinespeciesmonitoring.us/regions/pacific/current-projects/. 
Projects can be either major multi-year efforts, or one to 2-year 
special studies. The emphasis on monitoring in the GOA Study Area is 
directed towards passive acoustic monitoring and analysis, visual 
surveys, and marine mammal and salmonid telemetry. At least 15 GOA 
regional studies occurred under the marine species monitoring program 
during the previous GOA TMAA rule (effective April 2017 to April 2022), 
including 13 studies on marine mammals and two on salmonids.
    Specific monitoring under the previous regulations included the 
following projects:
     The continuation of the Navy's collaboration with NOAA on 
the Pacific Marine Assessment Program for Protected Species (PacMAPPS) 
survey. A systematic line transect survey in the Gulf of Alaska was 
completed in 2021 (Crance et al., 2022). A second PacMAPPS survey is 
planned for the Gulf of Alaska in 2023, pending ship availability. 
These surveys will increase knowledge of marine mammal occurrence, 
density, and population identity in the GOA Study Area (Crance et al., 
2022).
     A Characterizing the Distribution of ESA-Listed Salmonids 
in Washington and Alaska study. The goal of this study is to use a 
combination of acoustic and pop-up satellite tagging technology to 
provide critical information on spatial and temporal distribution of 
salmonids to inform salmon management, U.S. Navy training activities, 
and Southern Resident killer whale conservation. The study seeks to (1) 
determine the occurrence and timing of salmonids within the Navy 
training ranges; (2) describe the influence of environmental covariates 
on salmonid occurrence; and (3) describe the occurrence of salmonids in 
relation to Southern Resident killer whale distribution. Methods 
include acoustic telemetry (pinger tags) and pop-up satellite tagging. 
Reports include Smith and Huff (2019, 2020, 2021, 2022).
     A Telemetry and Genetic Identity of Chinook Salmon in 
Alaska study. The goal of this study is to provide critical information 
on the spatial and temporal distribution of Chinook salmon and to 
utilize genetic analysis techniques to inform salmon management. 
Tagging is

[[Page 666]]

occurring at several sites within the Gulf of Alaska. Reports include 
Seitz and Courtney (2021 and 2022).
     A North Pacific Humpback Whale Tagging study. This project 
combines tagging, biopsy sampling, and photo-identification efforts 
along the United States west coast and Hawaii to examine movement 
patterns and whale use of Navy training and testing areas and NMFS-
identified BIAs, examine migration routes, and analyze dive behavior 
and ecological relationships between whale locations and oceanographic 
conditions (Irvine et al., 2020; Mate et al., 2017a, 2017b, 2017c, 
2018a, 2018b, 2019a, 2019b, 2019c, 2020; Palacios et al., 2020a, 2020b, 
2020c, 2021).
     A Passive Acoustic Monitoring of Marine Mammals in the 
Gulf of Alaska study. The objective of this study was to determine the 
spatial distribution and occurrence of beaked whales, other 
odontocetes, and baleen whales in offshore areas using bottom-mounted 
passive acoustic recorders and deep-diving autonomous gliders (Rice et 
al., 2018, 2019, 2020, 2021; Wiggins et al., 2017 and 2018).
    Future monitoring efforts in the GOA Study Area are anticipated to 
continue along the same objectives: determining the species and 
populations of marine mammals present and potentially exposed to Navy 
training activities in the GOA Study Area, through tagging, passive 
acoustic monitoring, refined modeling, photo identification, biopsies, 
and visual monitoring, as well as characterizing spatial and temporal 
distribution of salmonids, including Chinook salmon.
    Projects that are currently under consideration for the 2022-2029 
rule are listed below. 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.
     PacMAPPS Survey--A second PacMAPPS survey is planned for 
the GOA in 2023, pending ship availability. These surveys will increase 
knowledge of marine mammal occurrence, density, and population identity 
in the GOA Study Area. The survey design would cover a portion of the 
WMA and the continental shelf where NMFS is currently considering 
revising the North Pacific Right Whale critical habitat.
     Analysis of Killer Whale Ecotypes in the Gulf of Alaska--
This study would use previously recorded passive acoustic monitoring 
data to analyze killer whale ecotypes in the Gulf of Alaska.
     Passive Acoustic Monitoring in the WMA--The objective of 
this study would be to determine the spatial distribution and 
occurrence of beaked whales, other odontocetes, and baleen whales in 
offshore areas using bottom-mounted passive acoustic recorders and 
deep-diving autonomous gliders.
     Telemetry of Chinook Salmon in Alaska--Efforts will 
continue to track active tags that were previously deployed on salmon.

Adaptive Management

    The regulations governing the take of marine mammals incidental to 
Navy training activities in the GOA Study Area contain an adaptive 
management component. Our understanding of the effects of Navy training 
and testing 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 Navy 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 will 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 will publish a notice of the planned LOA 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.

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 were several different reporting requirements pursuant to the 
2017-2022 regulations. All of these reporting requirements will 
continue under this rule for the 7-year period; however, the reporting 
schedule for the GOA Annual Training Report has been slightly changed 
to align the reporting schedule with the activity period (see the GOA 
Annual Training Report section, below).
    Notification of Injured, Live Stranded, or Dead Marine Mammals
    The Navy will 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 at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.

Annual GOA Marine Species Monitoring Report

    The Navy will submit an annual report to NMFS of the GOA Study Area 
monitoring, which will be included in a Pacific-wide monitoring report 
and include results specific to the GOA Study Area, describing the 
implementation and results of monitoring from the previous calendar 
year. Data collection methods will be standardized across Pacific Range 
Complexes including the MITT, HSTT, NWTT, and GOA Study Areas to the 
best extent practicable, to allow for comparison among different 
geographic locations. The report will be submitted to the Director, 
Office of Protected Resources, NMFS, either within 3 months after the 
end of the calendar year, or within 3 months after the conclusion of 
the monitoring year, to be determined by the Adaptive Management 
process. NMFS will submit comments or questions on the draft monitoring 
report, if any, within 3 months of receipt. The report will be

[[Page 667]]

considered final after the Navy has addressed NMFS' comments, or 3 
months after submittal if NMFS does not provide comments on the report. 
The report will describe progress of knowledge made with respect to 
monitoring study questions across multiple Navy ranges associated with 
the ICMP. Similar study questions will be treated together so that 
progress on each topic is summarized across all Navy ranges. The report 
need not include analyses and content that does not provide direct 
assessment of cumulative progress on the monitoring plan study 
questions. This will allow the Navy to provide a cohesive monitoring 
report covering multiple ranges (as per ICMP goals), rather than 
entirely separate reports for the MITT, HSTT, NWTT, and GOA Study 
Areas.

GOA Annual Training Report

    Each year in which training activities are conducted in the GOA 
Study Area, the Navy will submit one preliminary report (Quick Look 
Report) to NMFS detailing the status of applicable sound sources within 
21 days after the completion of the training activities in the GOA 
Study Area. Each year in which activities are conducted, the Navy will 
also submit a detailed report (GOA Annual Training Report) to the 
Director, Office of Protected Resources, NMFS within 3 months after 
completion of the training activities. The Phase II rule required the 
Navy to submit the GOA Annual Training Report within 3 months after the 
anniversary of the date of issuance of the LOA. NMFS will submit 
comments or questions on the report, if any, within one month of 
receipt. The report will be considered final after the Navy has 
addressed NMFS' comments, or one month after submittal if NMFS does not 
provide comments on the report. The annual reports will contain 
information about the MTE, (exercise designator, date that the exercise 
began and ended, location, number and types of active and passive sonar 
sources used in the exercise, number and types of vessels and aircraft 
that participated in the exercise, etc.), individual marine mammal 
sighting information for each sighting in each exercise where 
mitigation was implemented, a mitigation effectiveness evaluation, and 
a summary of all sound sources used (total hours or quantity of each 
bin of sonar or other non-impulsive source; total annual number of each 
type of explosive(s); and total annual expended/detonated rounds (bombs 
and large-caliber projectiles) for each explosive bin).
    The annual report (which, as stated above, will only be required 
during years in which activities are conducted) 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 report will 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 GOA SEIS/OEIS and MMPA final rule. The 
analysis in the detailed report will 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 seven) would also serve as the 
comprehensive close-out report and include both the final year annual 
use compared to annual authorization as well as a cumulative 7-year 
annual use compared to 7-year authorization. This report will also note 
any years in which training did not occur. NMFS will submit comments on 
the draft close-out report, if any, within 3 months of receipt. The 
report will be considered final after the Navy has addressed NMFS' 
comments, or 3 months after the submittal of the draft if NMFS does not 
provide comments. Information included in the annual reports may be 
used to inform future adaptive management of activities within the GOA 
Study Area. See the regulations below for more detail on the content of 
the annual report.

Other Reporting and Coordination

    The Navy will continue to report and coordinate with NMFS for the 
following:
     Annual marine species monitoring technical review meetings 
that also include researchers and the Marine Mammal Commission 
(currently, every two years a joint Pacific-Atlantic meeting is held); 
and
     Annual Adaptive Management meetings (in-person or remote, 
as circumstances allow and agreed upon by NMFS and the Navy) that also 
include the Marine Mammal Commission (and occur in conjunction with the 
annual monitoring technical review meetings).
    Further, the Navy will coordinate with NMFS prior to conducting 
exercises within the GOA Study Area. This may occur as a part of 
coordination the Navy does with other local stakeholders.

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 considering 
how Level A harassment or Level B harassment (as presented in Table 
32), factor into the negligible impact analysis, in addition to 
considering the number of estimated takes, 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).
    In the Estimated Take of Marine Mammals section, we identified the 
subset of potential effects that are expected to rise to the level of 
takes both annually and over the seven-year period covered by this 
rule, and then identified the maximum number of harassment takes that 
are reasonably expected to occur based on the methods described. The 
impact that any given take will have on an individual, and ultimately 
the species or stock, 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 rule 
we evaluated the likely impacts of the enumerated maximum number of 
harassment takes that are reasonably

[[Page 668]]

expected to occur, and are authorized, in the context of the specific 
circumstances surrounding these predicted takes. 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 Navy's specified activities will 
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).
    As explained in the Estimated Take of Marine Mammals section, no 
take by serious injury or mortality is authorized or anticipated to 
occur.
    The specified activities reflect representative levels of training 
activities. The Description of the Specified Activities 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 will not exceed the maximum annual totals and 7-year 
totals indicated in Table 32. (Further, as noted previously, the GOA 
Study Area training activities will not occur continuously throughout 
the year, but rather, for a maximum of 21 days once annually between 
April and October.) We base our analysis and negligible impact 
determination on the maximum number of takes that are reasonably 
expected to occur annually and are authorized, although, as stated 
before, the number of takes are only a 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 in this General Negligible Impact Analysis section that 
applies to all the species listed in Table 32, given that some of the 
anticipated effects of the Navy's training activities on marine mammals 
are expected to be relatively similar in nature. Then, in the Group and 
Species-Specific Analyses section, we subdivide into discussions of 
Mysticetes, Odontocetes, and pinnipeds, as there are broad life history 
traits that support an overarching discussion of some factors 
considered within the analysis for those groups (e.g., high-level 
differences in feeding strategies). Last, we 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 or stock 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 Navy's 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.
Harassment
    The Navy's harassment take request is based on a model and 
quantitative assessment of procedural mitigation, which NMFS reviewed 
and concurs appropriately predicts the maximum amount of harassment 
that is likely to occur, with the exception of the Eastern North 
Pacific stock of gray whale, and the Western North Pacific stock of 
humpback whale, for which NMFS has proposed authorizing 4 and 3 Level B 
harassment takes annually, respectively, as described in the Estimated 
Take of Marine Mammals section. The model calculates sound energy 
propagation from sonar, other active acoustic sources, and explosives 
during naval 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 model intentionally err on the side of overestimation when 
there are unknowns. Naval activities are modeled as though they would 
occur regardless of proximity to marine mammals, meaning that no 
mitigation is considered (e.g., no power down or shut down) and without 
any avoidance of the activity by the animal. As described above in the 
Estimated Take of Marine Mammals section, no mortality was modeled for 
any species for the TMAA activities, and therefore the quantitative 
post-modeling analysis that allows for the consideration of mitigation 
to prevent mortality, which has been applied in other Navy rules, was 
appropriately not applied here. (Though, as noted in the Estimated Take 
of Marine Mammals section, where the analysis indicates mitigation 
would effectively reduce risk, the model-estimated PTS are considered 
reduced to TTS.) NMFS provided input to, independently reviewed, and 
concurred with the Navy on this process and the Navy's analysis, which 
is described in detail in Section 6 of the Navy's rulemaking/LOA 
application that was used to quantify harassment takes for this rule.
    Generally speaking, the Navy 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 evoke a response of equal 
magnitude (DeRuiter, 2012, Falcone et al., 2017). The estimated number 
of takes by Level A harassment and Level B harassment does not equate 
to the number of individual animals the Navy expects 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 annually and 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. Some 
individuals may experience multiple instances of take (i.e., on 
multiple days) over the course of the 21-day exercise, 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 to give us a relative sense of where a larger 
portion of a species or stock is being taken by Navy activities, where 
there is a higher likelihood that the same individuals are being taken 
on multiple days, and where that number of days might be higher or more 
likely sequential. Where the number of instances of take is 100 percent 
or less of the abundance and there is no information to specifically 
suggest that a small subset of animals will be repeatedly taken over a 
high number of sequential days, the overall magnitude is generally 
considered low, as it could on one extreme mean that every individual 
taken will be taken on no more than one day annually (a very minimal 
impact) or, more likely, that some smaller portion of individuals are 
taken on one day annually, some are taken on more than one day, and 
some are not taken at all.

[[Page 669]]

    In the ocean, the Navy's 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 or 
stocks repeated exposures across different activities could occur over 
the 21-day period. In short, for some species or stocks we expect that 
the total anticipated takes represent exposures of a smaller number of 
individuals of which some will be exposed multiple times, but based on 
the nature of the Navy activities and the movement patterns of marine 
mammals, it is unlikely that individuals from most stocks will be taken 
over more than a few non-sequential days and, as described elsewhere, 
the nature of the majority of the exposures is expected to be of a less 
severe nature and based on the numbers and duration of the activity (no 
more than 21 days) any individual exposed multiple times is still only 
taken on a small percentage of the days of the year. We also note that, 
in the unlikely event that an individual is taken on two or three 
sequential days (and the total number of days in which the individual 
was taken in a year remained low), such takes would not be expected to 
impact an individual's (of any hearing sensitivity) reproduction or 
survival.
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 in the proposed rule 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. Takes by Level B harassment, then, may have a 
stress-related physiological component as well; however, we would not 
expect the Navy's 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 
take by Level B harassment. As described in the Navy's application, the 
Navy identified (with NMFS' input) the types of behaviors that would be 
considered a take: moderate behavioral responses as characterized in 
Southall et al. (2007) (e.g., altered migration paths or dive profiles; 
interrupted nursing, breeding, or feeding; or avoidance) that also 
would be expected to continue for the duration of an exposure. The Navy 
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 cutoff 
distances that are used to predict how many instances of Level B 
harassment by behavioral disturbance would occur in a day. Take 
estimates alone do not provide information regarding the potential 
fitness or other biological consequences of the reactions 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 training activities would 
be primarily from ASW events. It is important to note that although ASW 
is one of the warfare areas of focus during Navy training, there are 
significant periods when active ASW sonars are not in use. Behavioral 
reactions are assumed more likely to be significant during MTEs than 
during other ASW activities due to the use of high-powered ASW sources 
as well as the duration (i.e., multiple days) and scale (i.e., multiple 
sonar platforms) of the MTEs.
    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 effects could 
occur when the 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.
    To help assess this, for sonar (MFAS/high frequency active sonar 
(HFAS)) used in the TMAA, the Navy provided information estimating the 
percentage of animals that may be taken by Level B harassment under 
each BRF that would occur within 6-dB increments (percentages discussed 
below in the Group and Species-Specific Analyses section). 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 (such as distance) are also important. The 
majority of takes by Level B harassment are expected to be in the form 
of milder responses (i.e., lower-level exposures that still rise to the 
level of take, but would likely be less severe in the range 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. 
However, depending on the context of an exposure (e.g., depth, 
distance, if an animal is engaged in important behavior such as 
feeding), a behavioral response can vary between species and 
individuals within a species. Specifically, given a range of behavioral 
responses that may be classified as Level B harassment, to the degree 
that higher received levels are expected to result in more severe 
behavioral responses, only a smaller percentage of the anticipated 
Level B harassment from Navy activities might necessarily be expected 
to potentially result in more severe responses (see the Group and 
Species-Specific Analyses section below for more detailed information). 
To fully understand the likely impacts of the predicted/authorized take 
on an individual (i.e., what is the likelihood or degree of fitness 
impacts), one must look closely at the available contextual 
information, such as the duration of likely exposures and the likely 
severity of the exposures (e.g., whether they will occur for a longer 
duration over sequential days or the comparative sound level that will 
be received). Ellison et al. (2012) and Moore and Barlow (2013), among 
others, emphasize the importance of context (e.g., behavioral state of 
the animals, distance from the sound source) in evaluating behavioral 
responses of marine mammals to acoustic sources.
Diel Cycle
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing on a diel cycle (24-hour cycle). Behavioral 
reactions to noise exposure, when taking place in a

[[Page 670]]

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 day or recur on 
subsequent days (Southall et al., 2007) due to diel and lunar patterns 
in diving and foraging behaviors observed in many cetaceans, including 
beaked whales (Baird et al., 2008, Barlow et al., 2020, Henderson et 
al., 2016, Schorr et al., 2014). 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 reactions 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 ASW 
activities, typically include vessels that are continuously moving at 
speeds typically 10-15 kn (18.5-27.8 km/hr), or higher, and likely 
cover large areas that are relatively far from shore (typically more 
than 3 nmi (6 km) from shore) and in waters greater than 600 ft (183 m) 
deep. Additionally, 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 Navy 
does 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 Navy conducts many 
different types of noise-producing activities over the course of the 
21-day exercise, 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 Appendix A (Navy Activity 
Descriptions) of the 2020 GOA FSEIS/OEIS. Sonar used during ASW would 
impart the greatest amount of acoustic energy of any category of sonar 
and other transducers analyzed in the Navy's rulemaking/LOA application 
and include hull-mounted, towed array, sonobuoy, and helicopter dipping 
sonars. Most ASW sonars are MFAS (1-10 kHz); however, some sources may 
use higher frequencies. ASW training activities using hull mounted 
sonar planned for the TMAA generally last for only a few hours (see 
Appendix A (Navy Activity Descriptions) of the 2022 GOA FSEIS/OEIS). 
Some ASW training activities typically last about 8 hours. Because of 
the need to train in a large variety of situations, the Navy does not 
typically conduct successive ASW exercises in the same locations. Given 
the average length of ASW 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 MFAS/HFAS at levels or 
durations likely to result in a substantive response that would then be 
carried on for more than 1 day or on successive days (and as noted 
previously, no LFAS use is planned by the Navy).
    Most planned explosive events are scheduled to occur over a short 
duration (1-3 hours); however, 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. All of these factors 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 
(and, for PTS, further corrected to account for mitigation and 
avoidance). As further noted, for 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. 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 estimated harassment 
takes in a population of 100, one can assume either that every 
individual will be exposed above acoustic thresholds in no more than 
one day, or that some smaller number will be exposed in one day but a 
few of those individuals will be exposed multiple days within a year 
and a few not exposed at all. Where the instances of take exceed 100 
percent of the population (i.e., are over 100 percent), 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 a larger 
portion of a species or stock is being taken by Navy 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 or stock.
    In the ocean, unlike a modeling simulation with static animals, 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, some 
repeated exposures across different activities could occur over the 
year with more resident species. Nonetheless, the episodic nature of 
activities in the TMAA (21 days per year) will mean less frequent 
exposures as compared to some other ranges. In short, we expect that 
for some stocks, 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 Navy's activities and the 
movement patterns of marine mammals, it is unlikely that individuals of 
most species or stocks would be taken over more than a few non-
sequential days within a year.
    When comparing the number of takes to the population abundance, 
which can be helpful in estimating both the proportion of the 
population affected by

[[Page 671]]

takes and 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. The SARs, where available, provide the 
official population estimate for a given species or stock in U.S. 
waters in a given year (and are typically based solely on the most 
recent survey data). When the stock is known to range well outside of 
U.S. Exclusive Economic Zone (EEZ) boundaries, population estimates 
based on surveys conducted only within the U.S. EEZ are known to be 
underestimates. The information used to estimate take includes the best 
available survey abundance data to model density layers. Accordingly, 
in calculating the percentage of takes versus abundance for each 
species or stock in order to assist in understanding both the 
percentage of the species or stock affected, as well as how many days 
across a year individuals could be taken, we use the data most 
appropriate for the situation. For the GOA Study Area, for all species 
and stocks except for beaked whales for which SAR data are unavailable, 
the most recent NMFS SARs are used to calculate the proportion of a 
population affected by takes.
    The stock abundance estimates in NMFS' SARs are typically generated 
from the most recent shipboard and/or aerial surveys conducted. In some 
cases, NMFS' abundance estimates show substantial year-to-year 
variability. However, for highly migratory species (e.g., large whales) 
or those whose geographic distribution extends well beyond the 
boundaries of the GOA Study Area (e.g., populations with distribution 
along the entire eastern Pacific Ocean rather than just the GOA Study 
Area), comparisons to the SAR are appropriate. Many of the stocks 
present in the GOA Study Area have ranges significantly larger than the 
GOA Study Area and that abundance is captured by the SAR. A good 
descriptive example is migrating large whales, which occur seasonally 
in the GOA. Therefore, at any one time there may be a stable number of 
animals, but over the course of the potential activity period (April to 
October) the entire population may enter the GOA 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 GOA Study Area.
Temporary Threshold Shift
    NMFS and the Navy have estimated that multiple species and stocks 
of marine mammals in the TMAA may sustain some level of TTS from active 
sonar. As discussed in the proposed rule in the Potential Effects of 
Specified Activities on Marine Mammals and their Habitat section, 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 to more severe. Table 43 to Table 48 indicate the number of 
takes by TTS that may be incurred by different species and stocks from 
exposure to active sonar and explosives. The TTS sustained by an animal 
is primarily classified by three characteristics:
    1. Frequency--Available data (of mid-frequency hearing specialists 
exposed to mid- or high-frequency sounds; Southall et al., 2019) 
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). The Navy's MF sources, which are the highest power and most 
numerous sources and the ones that cause the most take, 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 2 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 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 these sources is unlikely. As noted previously, the Navy is 
not planning LFAS use for the activities in this rulemaking. The 
frequency provides information about the cues to which a marine mammal 
may be temporarily less sensitive, but not the degree or duration of 
sensitivity loss. 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). TTS from explosives would be 
broadband.
    2. 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 dB level 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; 19-28 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 of the proposed rule, 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. However, since hull-mounted sonar 
such as the SQS-53 (MFAS) emits a ping typically every 50 seconds, 
incurring those levels of TTS is highly unlikely for such sources 
(though higher duty cycle hull mounted systems (bin MF12) could be used 
in the TMAA). 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 (19-28 km/hr) and nominally pinging every 50 seconds, the vessel 
would have traveled a minimum distance of approximately 257 m during 
the time between those pings. A scenario could occur where an animal 
does not leave the vicinity of a ship or travels a course parallel to 
the ship, however, the close distances required make TTS exposure 
unlikely. For a Navy vessel moving at a nominal 10 kn (19 km/hr), it is 
unlikely a marine mammal could maintain speed parallel to the ship and 
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 (i.e., single digits of sensitivity loss). 
To add context to this degree of TTS, individual marine mammals may 
regularly experience variations of 6 dB differences in hearing 
sensitivity across time (Finneran et al., 2000, 2002; Schlundt et al., 
2000).
    3. Duration of TTS (recovery time)--In the TTS laboratory studies 
(as

[[Page 672]]

discussed in the Potential Effects of Specified Activities on Marine 
Mammals and their Habitat section of the proposed rule), some using 
exposures of almost an hour in duration or up to 217 SEL, almost all 
individuals recovered within 1 day (or less, often in minutes), 
although in one study (Finneran et al., 2007), recovery took 4 days.
    Based on the range of degree and duration of TTS reportedly induced 
by exposures to non-pulse sounds of energy higher than that to which 
free-swimming marine mammals in the field are likely to be exposed 
during MFAS/HFAS training exercises in the TMAA, it is unlikely that 
marine mammals would ever sustain a TTS from MFAS that alters their 
sensitivity by more than 20 dB for more than a few hours--and any 
incident of TTS would likely be far less severe due to the short 
duration of the majority of the events during the 21 days and the speed 
of a typical vessel, especially given the fact that the higher power 
sources resulting in TTS are predominantly intermittent, which have 
been shown to result in shorter durations of TTS. Also, for the same 
reasons discussed in the Analysis and Negligible Impact Determination--
- Diel Cycle section, and because of the short distance within which 
animals would need to approach the sound source, it is unlikely that 
animals would be exposed to the levels necessary to induce TTS in 
subsequent time periods such that their recovery is impeded. 
Additionally, though the frequency range of TTS that marine mammals 
might sustain 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 
for any given species.
    Tables 43 to 48 indicate the maximum number of incidental takes by 
TTS for each species or stock that are likely to result from the Navy's 
activities. As a general point, the majority of these 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 HFAS sources (narrower band). As described above, we 
expect the majority of these takes to be in the form of mild (single-
digit), 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 within the 21 days, for several minutes to maybe a few 
hours at most each, a taken individual will have slightly diminished 
hearing sensitivity (slightly 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 limited 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 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, given the small number of times that any individual might 
incur TTS, the low degree of TTS and the short anticipated duration, 
and the low likelihood that one of these instances would occur in a 
time period in which the specific TTS overlapped the entirety of a 
critical signal, it is unlikely that TTS of the nature expected to 
result from the Navy activities would result in behavioral changes or 
other impacts that would impact any individual's (of any hearing 
sensitivity) reproduction or survival.
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 potential 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 further than 
higher frequencies and because they are more likely to overlap both the 
narrower low-frequency (LF) calls of mysticetes, as well as many non-
communication cues such as fish and invertebrate prey, and geologic 
sounds that inform navigation (although the Navy is not planning to use 
LFAS for the activities in this rulemaking). Masking is also more of a 
concern from continuous sources (versus intermittent sonar signals) 
where there is no quiet time between pulses within which auditory 
signals can be detected and interpreted. 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 Navy occasionally uses LF 
and more continuous sources (although, as noted above, the Navy 
proposes no LFAS use for the activities in this rulemaking), it is not 
in the contemporaneous aggregate amounts that would accrue to a masking 
concern. Specifically, the nature of the activities and sound sources 
used by the Navy do not support the likelihood of a level of masking 
accruing 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 (note also that the duty cycle for 
MF11 and MF12 sources is greater than 80 percent). Kingfisher mode is 
typically operated for relatively shorter durations. For the majority 
of other sources, the pulse length is significantly shorter than

[[Page 673]]

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 one second long, so, for example with hull-mounted 
sonar, there would be a 1 in 50 chance (and 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 one-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 ASW sonars and countermeasures use MF frequencies and a few 
use 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 when the source and animal are in 
close proximity. While data are limited on behavioral responses of 
marine mammals to continuously active sonars (Isojunno et al., 2020), 
mysticete species are known to be able 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 
and ships are 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 with the marine mammal subjected to the same exposure due to 
that movement. Most ASW activities are geographically dispersed and 
last for only a few hours, often with intermittent sonar use even 
within this period. Most ASW 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 Navy training that are not explicitly 
addressed above, many of either higher frequencies (meaning that the 
sounds generated attenuate even closer to the source) or lower amounts 
of operation, are similarly not expected to result in masking. 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 Navy 
uses are not expected to result in more than short-term, low impact 
masking that will not affect reproduction or survival.
PTS From Sonar Acoustic Sources and Explosives and Non-Auditory Tissue 
Damage From Explosives
    Tables 43 to 48 indicate the number of individuals of each species 
or stock for which Level A harassment in the form of PTS resulting from 
exposure to active sonar and/or explosives is estimated to occur. The 
Northeast Pacific stock of fin whale, Alaska stock of Dall's porpoise, 
and California stock of Northern elephant seal are the only stocks 
which may incur PTS (from sonar and explosives). For all other species/
stocks only take by Level B harassment (behavioral disturbance and/or 
TTS) is anticipated. No species/stocks have the potential to incur non-
auditory tissue damage from training activities. No species/stocks have 
the potential to incur non-auditory tissue damage from training 
activities.
    Data suggest that many marine mammals would deliberately avoid 
exposing themselves to the received levels of active sonar necessary to 
induce injury by moving away from or at least modifying their path to 
avoid a close approach. Additionally, in the unlikely event that an 
animal approaches the sonar-emitting vessel at a close distance, NMFS 
has determined that the mitigation measures (i.e., shutdown/powerdown 
zones for active sonar) would typically ensure that animals would not 
be exposed to injurious levels of sound. As discussed previously, the 
Navy utilizes both aerial (when available) and passive acoustic 
monitoring (during ASW exercises, passive acoustic detections are used 
as a cue for Lookouts' visual observations when passive acoustic assets 
are already participating in an activity) in addition to Lookouts on 
vessels to detect marine mammals for mitigation implementation. As 
discussed previously, these Level A harassment take numbers represent 
the maximum number of instances in which marine mammals would be 
reasonably expected to incur PTS, and we have analyzed them 
accordingly.
    If a marine mammal is able to approach a surface vessel within the 
distance necessary to incur PTS in spite of the mitigation measures, 
the likely speed of the vessel (nominally 10-15 kn (19-28 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 PTS. As discussed previously in 
relation to TTS, the likely consequences to the health of an individual 
that incurs PTS can range from mild to more serious dependent upon the 
degree of PTS and the frequency band it is in. The majority of any PTS 
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. Regardless of the frequency 
band, the more important point in this case is that any PTS accrued as 
a result of exposure to Navy activities would be expected to be of a 
small amount (single digits of dB hearing loss). 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 Navy implements mitigation measures (described in the 
Mitigation

[[Page 674]]

Measures section) during explosive activities, including delaying 
detonations when a marine mammal is observed in the mitigation zone. 
Nearly all explosive events will occur during daylight hours to improve 
the sightability of marine mammals and thereby improve mitigation 
effectiveness. Observing for marine mammals during the explosive 
activities will include visual and passive acoustic detection methods 
(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 (182.9 m) to 2,500 yd (2,286 m) depending on the source (e.g., 
explosive bombs; see Table 36 and Table 37). For all of these reasons, 
the mitigation measures associated with explosives are expected to 
further ensure that no non-auditory tissue damage occurs to any 
potentially affected species or stocks, and no species or stocks are 
anticipated to incur tissue damage during the period of the rule.

Group and Species-Specific Analyses

    In this section, we build on the general analysis that applies to 
all marine mammals in the GOA Study Area from the previous section, and 
include first 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 authorized from exposures to 
sonar and other active acoustic sources and in-air explosions at or 
above the water surface during the 7-year training period are shown in 
Table 32. The vast majority of predicted exposures (greater than 99 
percent) are expected to be non-injurious Level B harassment (TTS and 
behavioral reactions) from acoustic and explosive sources during 
training activities at relatively low received levels. A small number 
of takes by Level A harassment (PTS only) are predicted for three 
species (Dall's porpoise, fin whales, and Northern elephant seals).
    In the discussions below, the estimated takes by Level B harassment 
represent instances of take, not the number of individuals taken (the 
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. Below, we compare the total take 
numbers (including PTS, TTS, and behavioral disturbance) for species or 
stocks to their associated abundance estimates to evaluate the 
magnitude of impacts across the species or stock and to individuals. 
Generally, when an abundance percentage comparison is below 100, it 
suggests the following: (1) that not all of the individuals will be 
taken; (2) that, barring specific circumstances suggesting repeated 
takes of individuals (such as in circumstances where all activities 
resulting in take are focused in one area and time where the same 
individual marine mammals are known to congregate, such as pinnipeds at 
a haulout), the average or expected number of days for those 
individuals taken is one per year; and (3) that we would not expect any 
individuals to be taken more than a few times in a year, or for those 
days to be sequential. When it is more than 100 percent, it means there 
will definitely be some number of repeated takes of individuals. For 
example, if the percentage is 300, the average would be each individual 
is taken on 3 days in a year if all were taken, but it is more likely 
that some number of individuals will be taken more than three times and 
some number of individuals fewer or not at all. While it is not 
possible to know the maximum number of days across which individuals of 
a stock might be taken, in acknowledgement of the fact that it is more 
than the average, for the purposes of this analysis, we assume a number 
approaching twice the average. For example, if the percentage of take 
compared to the abundance is 800, we estimate that some individuals 
might be taken as many as 16 times. Those comparisons are included in 
the sections below.
    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 a PTS or TTS take may sometimes, for example, 
also be subject to behavioral disturbance at the same time. As 
described above in this section, the degree of PTS, 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 PTS 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 jeopardized, although those sorts of 
impacts are generally not expected to result from these activities. 
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 Level A 
harassment takes by PTS are so low (and zero in most cases) compared to 
abundance numbers that it is considered highly unlikely that any 
individual would be taken at those levels more than once.
    Occasional, milder behavioral reactions 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 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).
    If impacts to individuals are of a magnitude or severity such that 
either 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 
occurs 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 a portion of the population (typically 
approximately 50 percent). 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,

[[Page 675]]

while the death of an adult male has very little effect on population 
growth rates. However, as will be explained further in the sections 
below, the severity and magnitude of takes expected to result from Navy 
activities in the TMAA are such that energetic impacts of a scale that 
might affect reproductive success are not expected to occur at all.
    The analyses below in some cases address species collectively if 
they occupy the same functional hearing group (i.e., low, mid, and 
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 Navy's 
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 provide broad discussion of the expected effects on the 
mysticete, odontocete, and pinniped groups generally, 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 species and stocks will likely incur, the applicable 
mitigation, and the status of the species and stocks to support the 
negligible impact determinations for each species or stock. We have 
described above (in the General Negligible Impact Analysis section) the 
unlikelihood of any masking having effects that will impact the 
reproduction or survival of any of the individual marine mammals 
affected by the Navy's activities. We have also described in the 
Potential Effects of Specified Activities on Marine Mammals and their 
Habitat section of the proposed rule that the specified activities 
would not have adverse or long-term impacts on marine mammal habitat, 
and therefore the unlikelihood of any habitat impacts affecting the 
reproduction or survival of any individual marine mammals affected by 
the Navy's activities. No new information has been received that 
affects that analysis and conclusion.
    For mysticetes, there is no predicted non-auditory tissue damage 
from explosives for any species, and only two fin whales could be taken 
by PTS by exposure to in-air explosions at or above the water surface. 
Much of the discussion below focuses on the behavioral effects and the 
mitigation measures that reduce the probability or severity of effects. 
Because there are species-specific and stock-specific considerations, 
at the end of the section we break out our findings on a species-
specific and, for one species, stock-specific basis.
    In Table 43 below for mysticetes, we indicate for each species and 
stock the total annual numbers of take by Level A harassment and Level 
B harassment, and a number indicating the instances of total take as a 
percentage of abundance.

   Table 43--Annual Estimated Takes by Level B Harassment and Level A Harassment for Mysticetes and Number Indicating the Instances of Total Take as a
                                                          Percentage of Species/Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                            Instances of indicated types of
                                                                                  incidental take \1\
                                                                       ----------------------------------------                            Instances of
                                                                            Level B harassment       Level A                  Abundance    total take as
                 Species                              Stock            ---------------------------  harassment  Total takes  (NMFS SARs)   percentage of
                                                                                       TTS (may   -------------                  \2\         abundance
                                                                         Behavioral  also include
                                                                        disturbance  disturbance)      PTS
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Pacific right whale................  Eastern North Pacific......            1             2            0            3           31             9.7
Humpback whale...........................  California, Oregon, &                  2             8            0           10        4,973              <1
                                            Washington.                          11            68            0           79       10,103              <1
                                           Central North Pacific......        \3\ 3             0            0        \3\ 3        1,107              <1
                                           Western North Pacific......
Blue whale...............................  Central North Pacific......            0             3            0            3          133             2.3
                                           Eastern North Pacific......            4            32            0           36        1,898             1.9
Fin whale................................  Northeast Pacific..........          115         1,127            2        1,244    \4\ 3,168            39.3
Sei whale................................  Eastern North Pacific......            3            34            0           37          519             7.1
Minke whale..............................  Alaska.....................            6            44            0           50      \5\ 389            12.9
Gray whale...............................  Eastern North Pacific......        \3\ 4             0            0        \3\ 4       26,960              <1
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate
  individuals, especially for behavioral disturbance.
\2\ Presented in the 2021 SARs or most recent SAR.
\3\ The Navy's Acoustic Effects Model estimated zero takes for each of these stocks. However, NMFS conservatively authorized take by Level B harassment
  of one group of Western North Pacific humpback whale and one group of Eastern North Pacific gray whale. The annual take estimates reflect the average
  group sizes of on- and off-effort survey sightings of humpback whale and gray whale (excluding an outlier of an estimated 25 gray whales in one group)
  reported in Rone et al. (2017).
\4\ The SAR reports this stock abundance assessment as provisional and notes that it is an underestimate for the entire stock because it is based on
  surveys which covered only a small portion of the stock's range.
\5\ The 2018 final SAR (most recent SAR) for the Alaska stock of minke whales reports the stock abundance as unknown because only a portion of the
  stock's range has been surveyed. To be conservative, for this stock we report the smallest estimated abundance produced during recent surveys.

    The majority of takes by harassment of mysticetes in the TMAA are 
caused by ASW activities. Anti-submarine activities include sources 
from the MFAS bin (which includes hull-mounted sonar). They are high 
level, narrowband sources in the 1-10 kHz range, which intersect what 
is estimated to be the most sensitive area of hearing for mysticetes. 
They also are used in a large portion of exercises (see Table 1 and 
Table 3). Most of the takes (88 percent) from the MF1 bin in the TMAA 
would result from received levels between 166 and 178 dB SPL, while 
another 11 percent would result from exposure between 160 and 166 dB 
SPL. For the remaining active sonar bin types, the percentages are as 
follows: MF4 = 97 percent between 142 and 154 dB SPL and MF5 = 97 
percent between 118 and 142 dB SPL. For mysticetes, exposure to 
explosives would result in comparatively smaller numbers of takes

[[Page 676]]

by Level B harassment by behavioral disturbance (0-11 per stock) and 
TTS takes (0-2 per stock). Based on this information, the majority of 
the takes by Level B harassment by behavioral disturbance are expected 
to be of low to sometimes moderate severity and of a relatively shorter 
duration. Exposure to explosives would also result in two takes by 
Level A harassment by PTS of the Northeast Pacific stock of fin whale. 
No mortality or serious injury and no Level A harassment from non-
auditory tissue damage from training activities is anticipated or 
authorized for any species or stock.
    Research and observations show that if mysticetes are exposed to 
sonar or other active acoustic sources they may react in a number of 
ways depending on the characteristics of the sound source, their 
experience with the sound source, and whether they are migrating or on 
seasonal feeding or breeding grounds. Behavioral reactions may include 
alerting, breaking off feeding dives and surfacing, diving or swimming 
away, or no response at all (Department of Defense, 2017; Nowacek, 
2007; Richardson, 1995; Southall et al., 2007). Overall, mysticetes 
have been observed to be more reactive to acoustic disturbance when a 
noise source is located directly on their migration route. Mysticetes 
disturbed while migrating could pause their migration or route around 
the disturbance, while males en route to breeding grounds have been 
shown to be less responsive to disturbances. Although some may pause 
temporarily, they will resume migration shortly after the exposure 
ends. Animals disturbed while engaged in other activities such as 
feeding or reproductive behaviors may be more likely to ignore or 
tolerate the disturbance and continue their natural behavior patterns. 
Alternately, adult females with calves may be more responsive to 
stressors.
    As noted in the Potential Effects of Specified Activities on Marine 
Mammals and Their Habitat section of the proposed rule, while there are 
multiple examples from behavioral response studies of odontocetes 
ceasing their feeding dives when exposed to sonar pulses at certain 
levels, blue whales were less likely to show a visible response to 
sonar exposures at certain levels when feeding than when traveling. 
However, Goldbogen et al. (2013) indicated some horizontal displacement 
of deep foraging blue whales in response to simulated MFAS. Southall et 
al. (2019b) observed that after exposure to simulated and operational 
mid-frequency active sonar, more than 50 percent of blue whales in 
deep-diving states responded to the sonar, while no behavioral response 
was observed in shallow-feeding blue whales. Southall et al. (2019b) 
noted that the behavioral responses they observed were generally brief, 
of low to moderate severity, and highly dependent on exposure context 
(behavioral state, source-to-whale horizontal range, and prey 
availability).
    Richardson et al. (1995) noted that avoidance (temporary 
displacement of an individual from an area) reactions are the most 
obvious manifestations of disturbance in marine mammals. Avoidance is 
qualitatively different from the startle or flight response, but also 
differs in the magnitude of the response (i.e., directed movement, rate 
of travel, etc.). Oftentimes avoidance is temporary, and animals return 
to the area once the noise has ceased. Some mysticetes may avoid larger 
activities as they move through an area, although the Navy's activities 
do not typically use the same training locations day-after-day during 
multi-day activities, except periodically in instrumented ranges, which 
are not present in the GOA Study Area. Therefore, displaced animals 
could return quickly after a large activity or MTE is completed.
    At most, only one MTE would occur per year (over a maximum of 21 
days), and additionally, MF1 mid-frequency active sonar is prohibited 
from June 1 to September 30 within the North Pacific Right Whale 
Mitigation Area. Explosives detonated below 10,000 ft. altitude 
(including at the water surface) are prohibited in the Continental 
Shelf and Slope Mitigation Area, including in the portion that overlaps 
the North Pacific Right Whale Mitigation Area. In the open waters of 
the Gulf of Alaska, the use of Navy sonar and other active acoustic 
sources is transient and is unlikely to expose the same population of 
animals repeatedly over a short period of time, especially given the 
broader-scale movements of mysticetes and the 21-day duration of the 
activities.
    The implementation of procedural mitigation and the sightability of 
mysticetes (especially given their large size) further reduces the 
potential for a significant behavioral reaction or a threshold shift to 
occur (i.e., shutdowns are expected to be successfully implemented), 
which is reflected in the amount and type of incidental take that is 
anticipated to occur and authorized.
    As noted previously, when an animal incurs a threshold shift, it 
occurs in the frequency from that of the source up to one octave above. 
This means that the vast majority of threshold shifts caused by Navy 
sonar sources will typically occur in the range of 2-20 kHz (from the 
1-10 kHz MF bin, though in a specific narrow band within this range as 
the sources are narrowband), and if resulting from hull-mounted sonar, 
will be in the range of 3.5-7 kHz. The majority of mysticete 
vocalizations occur in frequencies below 1 kHz, which means that TTS 
incurred by mysticetes will not interfere with conspecific 
communication. Additionally, many of the other critical sounds that 
serve as cues for navigation and prey (e.g., waves, fish, 
invertebrates) occur below a few kHz, which means that detection of 
these signals will not be inhibited by most threshold shift either. 
When we look in ocean areas where the Navy has been intensively 
training and testing with sonar and other active acoustic sources for 
decades, there is no data suggesting any long-term consequences to 
reproduction or survival rates of mysticetes from exposure to sonar and 
other active acoustic sources.
    All the mysticete species discussed in this section would benefit 
from the procedural mitigation measures described earlier in the 
Mitigation Measures section. Additionally, the Navy will issue 
awareness messages prior to the start of TMAA training activities to 
alert vessels and aircraft operating within the TMAA to the possible 
presence of concentrations of large whales, including mysticetes, 
especially when traversing on the continental shelf and slope where 
densities of these species may be higher. To maintain safety of 
navigation and to avoid interactions with marine mammals, the Navy will 
instruct vessels to remain vigilant to the presence of large whales 
that may be vulnerable to vessel strikes or potential impacts from 
training activities. Further, the Navy will limit activities and employ 
other measures in mitigation areas that would avoid or reduce impacts 
to mysticetes. Where these mitigation areas are expected to mitigate 
impacts to particular species or stocks (North Pacific right whale, 
humpback whale, gray whale), they are discussed in detail below.
    Below we compile and summarize the information that supports our 
determinations that the Navy's activities would not adversely affect 
any mysticete species or stock through effects on annual rates of 
recruitment or survival.

North Pacific Right Whale (Eastern North Pacific Stock)

    North Pacific right whales are listed as endangered under the ESA, 
and this species is currently one of the most endangered whales in the 
world

[[Page 677]]

(Clapham, 2016; NMFS, 2013, 2017; Wade et al., 2010). The current 
population trend is unknown. ESA-designated critical habitat for the 
North Pacific right whale is located in the western Gulf of Alaska off 
Kodiak Island and in the southeastern Bering Sea/Bristol Bay area (Muto 
et al., 2017; Muto et al., 2018b; Muto et al., 2020a); there is no 
designated critical habitat for this species within the GOA Study Area. 
North Pacific right whales are anticipated to be present in the GOA 
Study Area year round, but are considered rare, with a potentially 
higher density between June and September. A BIA for feeding (June 
through September; Ferguson et al., 2015b) overlaps with the TMAA 
portion of the GOA Study Area by approximately 2,051 km\2\ 
(approximately 7 percent of the feeding BIA and 1.4 percent of the 
TMAA). This BIA does not overlap with any portion of the WMA. This rule 
includes a North Pacific Right Whale Mitigation Area and Continental 
Shelf and Slope Mitigation Area, which both overlap with the portion of 
the North Pacific right whale feeding BIA that overlaps with the TMAA. 
From June 1 to September 30, Navy personnel will not use surface ship 
hull-mounted MF1 mid-frequency active sonar during training activities 
within the North Pacific Right Whale Mitigation Area. Further, Navy 
personnel will not detonate explosives below 10,000 ft altitude 
(including at the water surface) during training at all times in the 
Continental Shelf and Slope Mitigation Area (including in the portion 
that overlaps the North Pacific Right Whale Mitigation Area). These 
restrictions will reduce the severity of impacts to North Pacific right 
whales by reducing interference in feeding that could result in lost 
feeding opportunities or necessitate additional energy expenditure to 
find other good foraging opportunities.
    Regarding the magnitude of takes by Level B harassment (TTS and 
behavioral disturbance), only 3 instances of take by Level B harassment 
(2 TTS, and 1 behavioral disturbance) are estimated, which equate to 
about 10 percent of the very small estimated abundance. Given this very 
small estimate, repeated exposures of individuals are not anticipated. 
Regarding the severity of individual takes by Level B harassment by 
behavioral disturbance, we have explained that the duration of any 
exposure is expected to be between minutes and hours (i.e., relatively 
short) and the received sound levels largely below 172 dB with a small 
portion up to 184 dB (i.e., of a moderate or sometimes lower level). 
Regarding the severity of TTS takes, they are expected to be low-level, 
of short duration, and mostly not in a frequency band that would be 
expected to interfere with North Pacific right whale communication or 
other important low-frequency cues. Therefore, the associated lost 
opportunities and capabilities are not at a level that would impact 
reproduction or survival.
    Altogether, North Pacific right whales are listed as endangered 
under the ESA, and the current population trend is unknown. Only three 
instances of take are estimated to occur (a small portion of the 
stock), and any individual North Pacific right whale is likely to be 
disturbed at a low-moderate level. This low magnitude and severity of 
harassment effects is not expected to result in impacts on the 
reproduction or survival of any individuals, let alone have impacts on 
annual rates of recruitment or survival of this stock. No mortality or 
Level A harassment is anticipated or authorized. For these reasons, we 
have determined, in consideration of all of the effects of the Navy's 
activities combined, that the authorized take will have a negligible 
impact on the Eastern North Pacific stock of North Pacific right 
whales.

Humpback Whale (California/Oregon/Washington Stock)

    The California/Oregon/Washington (CA/OR/WA) stock of humpback 
whales includes individuals from three ESA DPSs: Central America 
(endangered), Mexico (threatened), and Hawaii (not listed). A small 
portion of ESA-designated critical habitat overlaps with the TMAA 
portion of the GOA Study Area (see Figure 4-1 of the Navy's rulemaking/
LOA application). The ESA-designated critical habitat does not overlap 
with any portion of the WMA. No other BIAs are identified for this 
species in the GOA Study Area. The SAR identifies this stock as stable 
(having shown a long-term increase from 1990 and then leveling off 
between 2008 and 2014). Navy personnel will not use surface ship hull-
mounted MF1 mid-frequency active sonar from June 1 to September 30 
within the North Pacific Right Whale Mitigation Area, which overlaps 18 
percent of the humpback whale critical habitat in the TMAA. Further, 
Navy personnel will not detonate explosives below 10,000 ft altitude 
(including at the water surface) during training at all times in the 
Continental Shelf and Slope Mitigation Area (including in the portion 
that overlaps the North Pacific Right Whale Mitigation Area), which 
fully overlaps the portion of the humpback whale critical habitat in 
the TMAA. These measures will reduce the severity of impacts to 
humpback whales by reducing interference in feeding that could result 
in lost feeding opportunities or necessitate additional energy 
expenditure to find other good opportunities.
    Regarding the magnitude of takes by Level B harassment (TTS and 
behavioral disturbance), the number of estimated total instances of 
take is 10 (8 TTS and 2 behavioral disturbance), which is less than 1 
percent of the abundance. Given the very low number of anticipated 
instances of take, only a very small portion of individuals in the 
stock are likely impacted and repeated exposures of individuals are not 
anticipated. Regarding the severity of those individual takes by Level 
B harassment by behavioral disturbance, we have explained that the 
duration of any exposure is expected to be between minutes and hours 
(i.e., relatively short) and the received sound levels largely below 
172 dB with a small portion up to 184 dB (i.e., of a moderate or 
sometimes lower level). Regarding the severity of TTS takes, they are 
expected to be low-level, of short duration, and mostly not in a 
frequency band that would be expected to interfere with humpback whale 
communication or other important low-frequency cues. Therefore, the 
associated lost opportunities and capabilities are not at a level that 
will impact reproduction or survival.
    Altogether, this population is stable (even though two of the three 
associated DPSs are listed as endangered or threatened under the ESA), 
only a very small portion of the stock is anticipated to be impacted, 
and any individual humpback whale is likely to be disturbed at a low-
moderate level. No mortality or serious injury and no Level A 
harassment is anticipated or authorized. This low magnitude and 
severity of harassment effects is not expected to result in impacts on 
the reproduction or survival of any individuals, let alone have impacts 
on annual rates of recruitment or survival of this stock. For these 
reasons, we have determined, in consideration of all of the effects of 
the Navy's activities combined, that the authorized take will have a 
negligible impact on the California/Oregon/Washington stock of humpback 
whales.

Humpback Whale (Central North Pacific Stock)

    The Central North Pacific stock of humpback whales consists of 
winter/spring humpback whale populations of the Hawaiian Islands which 
migrate

[[Page 678]]

primarily to foraging habitat in northern British Columbia/Southeast 
Alaska, the Gulf of Alaska, and the Bering Sea/Aleutian Islands. The 
population is increasing (Muto et al., 2020), the Hawaii DPS is not 
ESA-listed, and no BIAs have been identified for this species in the 
GOA Study Area. Navy personnel will not use surface ship hull-mounted 
MF1 mid-frequency active sonar from June 1 to September 30 within the 
North Pacific Right Whale Mitigation Area, which overlaps 18 percent of 
the humpback whale critical habitat within the TMAA. As noted above, 
the Hawaii DPS is not ESA-listed; however, this ESA-designated critical 
habitat still indicates the likely value of habitat in this area to 
non-listed humpback whales. Further, Navy personnel will not detonate 
explosives below 10,000 ft altitude (including at the water surface) 
during training at all times in the Continental Shelf and Slope 
Mitigation Area (including in the portion that overlaps the North 
Pacific Right Whale Mitigation Area), which fully overlaps the portion 
of the humpback whale critical habitat in the TMAA. These measures will 
reduce the severity of impacts to humpback whales by reducing 
interference in feeding that could result in lost feeding opportunities 
or necessitate additional energy expenditure to find other good 
opportunities.
    Regarding the magnitude of takes by Level B harassment (TTS and 
behavioral disturbance), the number of estimated instances of take 
compared to the abundance is less than 1 percent. This information and 
the complicated far-ranging nature of the stock structure indicates 
that only a very small portion of the stock is likely impacted. While 
no BIAs have been identified in the GOA Study Area, highest densities 
in the nearby Kodiak Island feeding BIA (July to September) and Prince 
William Sound feeding BIA (September to December) overlap with much of 
the potential window for the Navy's exercise in the GOA Study Area 
(April to October). Given that some whales may remain in the area 
surrounding these BIAs for some time to feed during the Navy's 
exercise, there may be a few repeated exposures of a few individuals, 
most likely on non-sequential days. Regarding the severity of those 
individual takes by Level B harassment by behavioral disturbance, we 
have explained that the duration of any exposure is expected to be 
between minutes and hours (i.e., relatively short) and the received 
sound levels largely below 172 dB with a small portion up to 184 dB 
(i.e., of a moderate or sometimes lower level). Regarding the severity 
of TTS takes, they are expected to be low-level, of short duration, and 
mostly not in a frequency band that would be expected to interfere with 
humpback whale communication or other important low-frequency cues. 
Therefore, the associated lost opportunities and capabilities are not 
at a level that will impact reproduction or survival.
    Altogether, this population is increasing and the associated DPS is 
not listed as endangered or threatened under the ESA. Only a very small 
portion of the stock is anticipated to be impacted and any individual 
humpback whale is likely to be disturbed at a low-moderate level. This 
low magnitude and severity of harassment effects is not expected to 
result in impacts on individual reproduction or survival, let alone 
have impacts on annual rates of recruitment or survival of this stock. 
No mortality or Level A harassment is anticipated or authorized. For 
these reasons, we have determined, in consideration of all of the 
effects of the Navy's activities combined, that the authorized take 
will have a negligible impact on the Central North Pacific stock of 
humpback whales.

Humpback Whale (Western North Pacific Stock)

    The Western North Pacific stock of humpback whales includes 
individuals from the Western North Pacific DPS, which is ESA-listed as 
endangered. A relatively small portion of ESA-designated critical 
habitat overlaps with the TMAA (2,708 km\2\ (1,046 mi\2\) of critical 
habitat Unit 5, 5,991 km\2\ (2,313 mi\2\) of critical habitat Unit 8; 
see Figure 4-1 of the Navy's rulemaking/LOA application). The ESA-
designated critical habitat does not overlap with any portion of the 
WMA. No other BIAs are identified for this species in the GOA Study 
Area. The current population trend for this stock is unknown. Navy 
personnel will not use surface ship hull-mounted MF1 mid-frequency 
active sonar from June 1 to September 30 within the North Pacific Right 
Whale Mitigation Area, which overlaps 18 percent of the humpback whale 
critical habitat within the TMAA. Further, Navy personnel will not 
detonate explosives below 10,000 ft altitude (including at the water 
surface) during training at all times in the Continental Shelf and 
Slope Mitigation Area (including in the portion that overlaps the North 
Pacific Right Whale Mitigation Area), which fully overlaps the portion 
of the humpback whale critical habitat in the TMAA. These measures will 
reduce the severity of impacts to humpback whales by reducing 
interference in feeding that could result in lost feeding opportunities 
or necessitate additional energy expenditure to find other good 
opportunities.
    Regarding the magnitude of takes by Level B harassment (behavioral 
disturbance only), the number of estimated total instances of take is 
three, which is less than 1 percent of the abundance. Given the very 
low number of anticipated instances of take, only a very small portion 
of individuals in the stock are likely impacted and repeated exposures 
of individuals are not anticipated. Regarding the severity of those 
individual takes by Level B harassment by behavioral disturbance, we 
have explained that the duration of any exposure is expected to be 
between minutes and hours (i.e., relatively short) and the received 
sound levels largely below 172 dB with a small portion up to 184 dB 
(i.e., of a moderate or sometimes lower level).
    Altogether, the status of this stock is unknown, only a very small 
portion of the stock is anticipated to be impacted (3 individuals), and 
any individual humpback whale is likely to be disturbed at a low-
moderate level. No mortality, serious injury, Level A harassment, or 
TTS is anticipated or authorized. This low magnitude and severity of 
harassment effects is not expected to result in impacts on the 
reproduction or survival of any individuals, let alone have impacts on 
annual rates of recruitment or survival of this stock. For these 
reasons, we have determined, in consideration of all of the effects of 
the Navy's activities combined, that the authorized take will have a 
negligible impact on the Western North Pacific stock of humpback 
whales.

Blue Whale (Central North Pacific Stock and Eastern North Pacific 
Stock)

    Blue whales are listed as endangered under the ESA throughout their 
range, but there is no ESA designated critical habitat and no BIAs have 
been identified for this species in the GOA Study Area. The current 
population trend for the Central North Pacific stock is unknown, and 
the Eastern North Pacific stock is stable.
    Regarding the magnitude of takes by Level B harassment (TTS and 
behavioral disturbance), the number of estimated total instances of 
take compared to the abundance is 2 percent for both the Central North 
Pacific stock, and the Eastern North Pacific stock. For the Central 
North Pacific stock, only 3 instances of take (TTS) are anticipated.

[[Page 679]]

    Given the range of both blue whale stocks, the absence of any known 
feeding or aggregation areas, and the very low number of anticipated 
instances of take of the Central North Pacific stock, this information 
indicates that only a small portion of individuals in the stock are 
likely impacted and repeated exposures of individuals are not 
anticipated. Regarding the severity of those individual takes by Level 
B harassment by behavioral disturbance, we have explained that the 
duration of any exposure is expected to be between minutes and hours 
(i.e., relatively short) and the received sound levels largely below 
172 dB with a small portion up to 184 dB (i.e., of a moderate or 
sometimes lower level). Regarding the severity of TTS takes, we have 
explained that they are expected to be low-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. 
Therefore, the associated lost opportunities and capabilities are not 
at a level that would impact reproduction or survival.
    Altogether, blue whales are listed as endangered under the ESA 
throughout their range, the current population trend for the Central 
North Pacific stock is unknown, and the Eastern North Pacific stock is 
stable. Only a small portion of the stocks are anticipated to be 
impacted, and any individual blue whale is likely to be disturbed at a 
low-moderate level. The low magnitude and severity of harassment 
effects is not expected to result in impacts on the reproduction or 
survival of any individuals, let alone have impacts on annual rates of 
recruitment or survival of this stock. No mortality and no Level A 
harassment is anticipated or authorized. For these reasons, we have 
determined, in consideration of all of the effects of the Navy's 
activities combined, that the authorized take will have a negligible 
impact on the Central North Pacific stock and the Eastern North Pacific 
stock of blue whales.

Fin Whale (Northeast Pacific Stock)

    Fin whales are listed as endangered under the ESA throughout their 
range, but there is no ESA designated critical habitat and no BIAs have 
been identified for this species in the GOA Study Area. The SAR 
identifies this stock as increasing.
    Regarding the magnitude of takes by Level B harassment (TTS and 
behavioral disturbance), the number of estimated total instances of 
take compared to the abundance is 39 percent (though, as noted in Table 
43, the SAR reports the stock abundance assessment as provisional and 
notes that it is an underestimate for the entire stock because it is 
based on surveys which covered only a small portion of the stock's 
range, and therefore 39 percent is likely an overestimate). Given the 
large range of the stock and short duration of the Navy's activities in 
the GOA Study Area, this information suggests that notably fewer than 
half of the individuals of the stock will likely be impacted, and that 
most affected individuals will likely be disturbed on a few days within 
the 21-day exercise, with the days most likely being non-sequential. 
Regarding the severity of those individual takes by Level B harassment 
by behavioral disturbance, we have explained that the duration of any 
exposure is expected to be between minutes and hours (i.e., relatively 
short) and the received sound levels largely below 172 dB with a small 
portion up to 184 dB (i.e., of a moderate or sometimes lower level). 
Regarding the severity of TTS takes, they are expected to be low-level, 
of short duration, and mostly not in a frequency band that would be 
expected to interfere with fin whale communication or other important 
low-frequency cues. Therefore, the associated lost opportunities and 
capabilities are not at a level that will impact reproduction or 
survival.
    For these same reasons (low level and frequency band), while a 
small permanent loss of hearing sensitivity (PTS) may include some 
degree of energetic costs for compensating or may mean some small loss 
of opportunities or detection capabilities, at the expected scale the 
estimated two takes by Level A harassment by PTS will be unlikely to 
impact behaviors, opportunities, or detection capabilities to a degree 
that would interfere with reproductive success or survival of those 
individuals. Thus, the two takes by Level A harassment by PTS are 
unlikely to affect rates of recruitment and survival for the stock.
    Altogether, fin whales are listed as endangered under the ESA, 
though this population is increasing. Only a small portion of the stock 
is anticipated to be impacted, and any individual fin whale is likely 
to be disturbed at a low-moderate level. This low magnitude and 
severity of harassment effects is not expected to result in impacts on 
reproduction or survival of any individuals, let alone have impacts on 
annual rates of recruitment or survival of this stock. No mortality or 
serious injury and no Level A harassment from non-auditory tissue 
damage is anticipated or authorized. For these reasons, we have 
determined, in consideration of all of the effects of the Navy's 
activities combined, that the authorized take will have a negligible 
impact on the Northeast Pacific stock of fin whales.

Sei Whale (Eastern North Pacific Stock)

    The population trend of this stock is unknown, however sei whales 
are listed as endangered under the ESA throughout their range. There is 
no ESA designated critical habitat and no BIAs have been identified for 
this species in the GOA Study Area.
    Regarding the magnitude of takes by Level B harassment (TTS and 
behavioral disturbance), the number of estimated total instances of 
take compared to the abundance is 7 percent. This information and the 
rare occurrence of sei whales in the TMAA suggests that only a small 
portion of individuals in the stock will likely be impacted and 
repeated exposures of individuals are not anticipated. Regarding the 
severity of those individual takes by Level B harassment by behavioral 
disturbance, we have explained that the duration of any exposure is 
expected to be between minutes and hours (i.e., relatively short) and 
the received sound levels largely below 172 dB with a small portion up 
to 184 dB (i.e., of a moderate or sometimes lower level). Regarding the 
severity of TTS takes, they are expected to be low-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. Therefore, the associated lost opportunities and capabilities are 
not at a level that will impact reproduction or survival.
    Altogether, the status of the stock is unknown and the species is 
listed as endangered, only a small portion of the stock is anticipated 
to be impacted, and any individual sei whale is likely to be disturbed 
at a low-moderate level. This low magnitude and severity of harassment 
effects is not expected to result in impacts on individual reproduction 
or survival, much less annual rates of recruitment or survival. No 
mortality and no Level A harassment is anticipated or authorized. For 
these reasons, we have determined, in consideration of all of the 
effects of the Navy's activities combined, that the authorized take 
will have a negligible impact on the Eastern North Pacific stock of sei 
whales.

Minke Whale (Alaska Stock)

    The status of this stock is unknown and the species is not listed 
under the ESA. No BIAs have been identified for this species in the GOA 
Study Area.

[[Page 680]]

    Regarding the magnitude of takes by Level B harassment (TTS and 
behavioral disturbance), the number of estimated total instances of 
take compared to the abundance is 13 percent for the Alaska stock 
(based on, to be conservative, the smallest available provisional 
estimate in the SAR, which is derived from surveys that cover only a 
portion of the stock's range). Given the range of the Alaska stock of 
minke whales, this information indicates that only a small portion of 
individuals in this stock are likely to be impacted and repeated 
exposures of individuals are not anticipated. Regarding the severity of 
those individual takes by Level B harassment by behavioral disturbance, 
we have explained that the duration of any exposure is expected to be 
between minutes and hours (i.e., relatively short) and the received 
sound levels largely below 172 dB with a small portion up to 184 dB 
(i.e., of a moderate or sometimes lower level). Regarding the severity 
of TTS takes, they are expected to be low-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. 
Therefore, the associated lost opportunities and capabilities are not 
at a level that will impact reproduction or survival.
    Altogether, although the status of the stock is unknown, the 
species is not listed under the ESA as endangered or threatened, only a 
small portion of the stock is anticipated to be impacted, and any 
individual minke whale is likely to be disturbed at a low-moderate 
level. This low magnitude and severity of harassment effects is not 
expected to result in impacts on individual reproduction or survival, 
let alone have impacts on annual rates of recruitment or survival of 
this stock. No mortality, serious injury, or Level A harassment is 
anticipated or authorized. For these reasons, we have determined, in 
consideration of all of the effects of the Navy's activities combined, 
that the authorized take will have a negligible impact on the Alaska 
stock of minke whales.

Gray Whale (Eastern North Pacific Stock)

    The Eastern North Pacific stock of gray whale is not ESA-listed, 
and the SAR indicates that the stock is increasing. However, recent 
(2021-2022) surveys conducted by NMFS' Southwest Fisheries Science 
Center estimated that the population has declined to 16,650 whales, 
though the authors note that this stock has historically shown a 
pattern of population growth and decline that has not impacted the 
population in the long term (Eguchi et al., 2022). The TMAA portion of 
the GOA Study Area overlaps with a gray whale migration corridor that 
has been identified as a BIA (November-January (outside of the 
potential training window), southbound; March-May, northbound; Ferguson 
et al., 2015). The WMA portion of the GOA Study Area does not overlap 
with any known important areas for gray whales.
    Regarding the magnitude of takes by Level B harassment (behavioral 
disturbance only), the number of estimated total instances of take is 
four, which is less than 1 percent of the abundance, regardless of 
whether the number of takes is compared to the abundance in the SAR or 
Eguchi et al. (2022). Given the very low number of anticipated 
instances of take, only a very small portion of individuals in the 
stock are likely impacted and repeated exposures of individuals are not 
anticipated. Regarding the severity of those individual takes by Level 
B harassment by behavioral disturbance, we have explained that the 
duration of any exposure is expected to be between minutes and hours 
(i.e., relatively short) and the received sound levels largely below 
172 dB with a small portion up to 184 dB (i.e., of a moderate or 
sometimes lower level).
    Altogether, while we have considered the impacts of the gray whale 
UME, this population of gray whales is not endangered or threatened 
under the ESA. No mortality, Level A harassment, or TTS is anticipated 
or authorized. Only a very small portion of the stock is anticipated to 
be impacted, and any individual gray whale is likely to be disturbed at 
a low-moderate level. This low magnitude and severity of harassment 
effects is not expected to result in impacts on the reproduction or 
survival of any individuals, let alone have impacts on annual rates of 
recruitment or survival of this stock. For these reasons, we have 
determined, in consideration of all of the effects of the Navy's 
activities combined, that the authorized take will have a negligible 
impact on the Eastern North Pacific stock of gray 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 species and stocks will likely incur, the applicable 
mitigation, and the status of the species and stocks to support the 
negligible impact determinations for each species or stock. We have 
described (above in the General Negligible Impact Analysis section) the 
unlikelihood of any masking having effects that will impact the 
reproduction or survival of any of the individual marine mammals 
affected by the Navy's activities. We have also described above in the 
Potential Effects of Specified Activities on Marine Mammals and their 
Habitat section of the proposed rule that the specified activities 
would not have adverse or long-term impacts on marine mammal habitat, 
and therefore the unlikelihood of any habitat impacts affecting the 
reproduction or survival of any of the individual marine mammals 
affected by the Navy's activities. No new information has been received 
that affects this analysis and conclusion. There is no anticipated PTS 
from sonar or explosives for most odontocetes, with the exception of 
Dall's porpoise, which is discussed below. There is no anticipated M/SI 
or non-auditory tissue damage from sonar or explosives for any species. 
Here, we include information that applies to all of the odontocete 
species, which are then further divided and discussed in more detail in 
the following subsections: sperm whales; beaked whales; dolphins and 
small whales; and porpoises. These subsections include more specific 
information about the groups, as well as conclusions for each species 
or stock represented.
    The majority of takes by harassment of odontocetes in the TMAA are 
caused by sources from the MFAS bin (which includes hull-mounted sonar) 
because they are high level, typically narrowband sources at a 
frequency (in the 1-10 kHz range) that overlaps a more sensitive 
portion (though not the most sensitive) of the MF hearing range and 
they are used in a large portion of exercises (see Table 1 and Table 
3). For odontocetes other than beaked whales (for which these 
percentages are indicated separately in that section), most of the 
takes (95 percent) from the MF1 bin in the TMAA will result from 
received levels between 160 and 172 dB SPL. For the remaining active 
sonar bin types, the percentages are as follows: MF4 = 98 percent 
between 142 and 160 dB SPL and MF5 = 94 percent between 118 and 142 dB 
SPL. Based on this information, the majority of the takes by Level B 
harassment by behavioral disturbance are expected to be low to 
sometimes moderate in nature, but still of a generally shorter 
duration.
    For all odontocetes, takes from explosives (Level B harassment by 
behavioral disturbance, TTS, or PTS) comprise a very small fraction 
(and low number) of those caused by exposure to active sonar. For the 
following

[[Page 681]]

odontocetes, zero takes from explosives are expected to occur: sperm 
whale, killer whale, Pacific white-sided dolphin, Baird's beaked whale, 
and Stejneger's beaked whale. For Level B harassment by behavioral 
disturbance from explosives, one take is anticipated for Cuvier's 
beaked whale and 38 takes are anticipated for Dall's porpoise. No TTS 
or PTS is expected to occur from explosives for any stocks except 
Dall's porpoise. Because of the lower TTS and PTS thresholds for HF 
odontocetes, the Alaska stock of Dall's porpoise is expected to have 
229 takes by TTS and 45 takes by PTS from explosives.
    Because the majority of harassment takes of odontocetes result from 
the sources in the MFAS bin, the vast majority of threshold shift would 
occur upon receipt of a single frequency within the 1-10 kHz range and, 
therefore, the vast majority of threshold shift caused by Navy sonar 
sources would be at a single frequency within the range of 2-20 kHz. 
The frequency range within which any of the anticipated narrowband 
threshold shift would occur would fall directly within the range of 
most odontocete vocalizations (2-20 kHz) (though phocoenids generally 
communicate at higher frequencies (Soerensen et al., 2018; Clausen et 
al., 2010), which would not be impacted by this threshold shift). For 
example, the most commonly used hull-mounted sonar has a frequency 
around 3.5 kHz, and any associated threshold shift would be expected to 
be at around 7 kHz. However, odontocete vocalizations typically span a 
much wider range than this, and alternately, threshold shift from 
active sonar will often be in a narrower band (reflecting the narrower 
band source that caused it), which means that TTS incurred by 
odontocetes would typically only interfere with communication within a 
portion of their hearing range (if it occurred during a time when 
communication with conspecifics was occurring) and, as discussed 
earlier, it would only be expected to be of a short duration and 
relatively small degree. Odontocete echolocation occurs predominantly 
at frequencies significantly higher than 20 kHz (though there may be 
some small overlap at the lower part of their echolocating range for 
some species), which means that there is little likelihood that 
threshold shift, either temporary or permanent, would interfere with 
feeding behaviors. Many of the other critical sounds that serve as cues 
for navigation and prey (e.g., waves, fish, invertebrates) occur below 
a few kHz, which means that detection of these signals will not be 
inhibited by most threshold shift either. The low number of takes by 
threshold shift that might be incurred by individuals exposed to 
explosives would likely be lower frequency (5 kHz or less) and spanning 
a wider frequency range, which could slightly lower an individual's 
sensitivity to navigational or prey cues, or a small portion of 
communication calls, for several minutes to hours (if temporary) or 
permanently. There is no reason to think that the vast majority of the 
individual odontocetes taken by TTS would incur TTS on more than one 
day, although a small number could incur TTS on a few days at most. 
Therefore, odontocetes are unlikely to incur impacts on reproduction or 
survival as a result of TTS. The number of PTS takes from these sources 
are very low (0 for all species other than Dall's porpoise), and while 
spanning a wider frequency band, are still expected to be of a low 
degree (i.e., low amount of hearing sensitivity loss) and unlikely to 
affect reproduction or survival.
    The range of potential behavioral effects of sound exposure on 
marine mammals generally, and odontocetes specifically, has been 
discussed in detail previously. There are behavioral patterns that 
differentiate the likely impacts on odontocetes as compared to 
mysticetes. First, odontocetes echolocate to find prey, which means 
that they actively send out sounds to detect their prey. While there 
are many strategies for hunting, one common pattern, especially for 
deeper diving species, is many repeated deep dives within a bout, and 
multiple bouts within a day, to find and catch prey. As discussed 
above, studies demonstrate that odontocetes may cease their foraging 
dives in response to sound exposure. If enough foraging interruptions 
occur over multiple sequential days, and the individual either does not 
take in the necessary food, or must exert significant effort to find 
necessary food elsewhere, energy budget deficits can occur that could 
potentially result in impacts to reproductive success, such as 
increased cow/calf intervals (the time between successive calving). 
However, the relatively low impact of the Navy's activities on 
odontocetes in the TMAA indicate this is not likely to occur. Second, 
while many mysticetes rely on seasonal migratory patterns that position 
them in a geographic location at a specific time of the year to take 
advantage of ephemeral large abundances of prey (i.e., invertebrates or 
small fish, which they eat by the thousands), odontocetes forage more 
homogeneously on one fish or squid at a time. Therefore, if odontocetes 
are interrupted while feeding, it is often possible to find more prey 
relatively nearby.
    All the odontocete species and stocks discussed in this section 
would benefit from the procedural mitigation measures described earlier 
in the Mitigation Measures section.

Sperm Whale (North Pacific Stock)

    This section builds on the broader odontocete discussion above and 
brings together the discussion of the different types and amounts of 
take that sperm whales would likely incur, the applicable mitigation, 
and the status of the species/stock to support the negligible impact 
determination for the stock.
    Sperm whales are listed as endangered under the ESA. No critical 
habitat has been designated for sperm whales under the ESA and no BIAs 
for sperm whales have been identified in the GOA Study Area. The 
stock's current population trend is unknown. The Navy will issue 
awareness messages prior to the start of TMAA training activities to 
alert Navy ships and aircraft operating within the TMAA to the possible 
presence of increased concentrations of large whales, including sperm 
whales. This measure would further reduce any possibility of ship 
strike of sperm whales.
    In Table 44 below for sperm whales, we indicate the total annual 
numbers of take by Level A harassment and Level B harassment, and a 
number indicating the instances of total take as a percentage of 
abundance.

[[Page 682]]



 Table 44--Annual Estimated Takes by Level B Harassment and Level A Harassment for Sperm Whales in the TMAA and Number Indicating the Instances of Total
                                                     Take as a Percentage of Species/Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      Instances of indicated types of incidental take \1\
                                                     -----------------------------------------------------
                                                            Level B harassment         Level A harassment                                 Instances of
             Species                     Stock       -----------------------------------------------------   Total     Abundance (NMFS    total take as
                                                                       TTS (may also                         takes        SARs) \2\       percentage of
                                                        Behavioral        include             PTS                                           abundance
                                                        disturbance    disturbance)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale.....................  North Pacific.....             107               5                    0        112           \3\ 345              32.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate
  individuals, especially for disturbance.
\2\ Presented in the 2021 SARs or most recent SAR.
\3\ The SAR reports that this is an underestimate for the entire stock because it is based on surveys of a small portion of the stock's extensive range
  and it does not account for animals missed on the trackline or for females and juveniles in tropical and subtropical waters.

    Regarding the magnitude of takes by Level B harassment (TTS and 
behavioral disturbance), the number of estimated total instances of 
take compared to the abundance is 33 percent. Given the range of this 
stock, and the fact that the abundance estimate is an underestimate for 
the entire stock given that it is based on surveys of a small portion 
of the stock's extensive range and does not account for animals missed 
on the trackline or for females and juveniles in tropical and 
subtropical waters, this information indicates that fewer than half of 
the individuals in the stock are likely to be impacted, with those 
individuals disturbed on likely one, but not more than a few non-
sequential days within the 21 days per year. Additionally, while 
interrupted feeding bouts are a known response and concern for 
odontocetes, we also know that there are often viable alternative 
habitat options in the relative vicinity. Regarding the severity of 
those individual takes by Level B harassment by behavioral disturbance, 
we have explained that the duration of any exposure is expected to be 
between minutes and hours (i.e., relatively short) and the received 
sound levels largely below 172 dB (i.e., of a lower, to occasionally 
moderate, level and less likely to evoke a severe response). As 
discussed earlier in the Analysis and Negligible Impact Determination 
section, we anticipate more severe effects from takes when animals are 
exposed to higher received levels or for longer durations. Occasional 
milder Level B harassment by behavioral disturbance, as is expected 
here, is unlikely to cause long-term consequences for either individual 
animals or populations, even if some smaller subset of the takes are in 
the form of a longer (several hours or a day) and more moderate 
response. Regarding the severity of TTS takes, they are expected to be 
low-level, of short duration, and mostly not in a frequency band that 
would be expected to interfere with sperm whale communication or other 
important low-frequency cues. Therefore, the associated lost 
opportunities and capabilities are not at a level that will impact 
reproduction or survival.
    Altogether, sperm whales are listed as endangered under the ESA, 
and the current population trend is unknown. Fewer than half of the 
individuals of the stock are anticipated to be impacted, and any 
individual sperm whale is likely to be disturbed at a low-moderate 
level. This low magnitude and severity of harassment effects is not 
expected to result in impacts on reproduction or survival for any 
individuals, let alone have impacts on annual rates of recruitment or 
survival of this stock. No mortality, serious injury, or Level A 
harassment is anticipated or authorized. For these reasons, we have 
determined, in consideration of all of the effects of the Navy's 
activities combined, that the authorized take will have a negligible 
impact on the North Pacific stock of sperm whales.

Beaked Whales

    This section builds on the broader odontocete discussion above and 
brings together the discussion of the different types and amounts of 
take that different beaked whale species and stocks would likely incur, 
the applicable mitigation, and the status of the species and stocks to 
support the negligible impact determinations for each species or stock. 
For beaked whales, no mortality or Level A harassment is anticipated or 
authorized.
    In Table 45 below for beaked whales, we indicate the total annual 
numbers of take by Level A harassment and Level B harassment, and a 
number indicating the instances of total take as a percentage of 
abundance.

Table 45--Annual Estimated Takes by Level B Harassment and Level A Harassment for Beaked Whales in the TMAA and Number Indicating the Instances of Total
                                                     Take as a Percentage of Species/Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      Instances of indicated types of incidental take \1\
                                                     -----------------------------------------------------
                                                            Level B harassment         Level A harassment                                 Instances of
             Species                     Stock       -----------------------------------------------------   Total     Abundance (NMFS    total take as
                                                                       TTS (may also                         takes        SARs) \2\       percentage of
                                                        Behavioral        include             PTS                                           abundance
                                                        disturbance    disturbance)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baird's beaked whale............  Alaska............             106               0                    0        106                NA                NA
Cuvier's beaked whale...........  Alaska............             430               3                    0        433                NA                NA
Stejneger's beaked whale........  Alaska............             467              15                    0        482                NA                NA
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate
  individuals, especially for disturbance.
\2\ Reliable estimates of abundance for these stocks are currently unavailable.

    This first paragraph provides specific information that is in lieu 
of the parallel information provided for odontocetes as a whole. The 
majority of takes by harassment of beaked whales in the TMAA will be 
caused by sources from

[[Page 683]]

the MFAS bin (which includes hull-mounted sonar) because they are high 
level narrowband sources that fall within the 1-10 kHz range, which 
overlap a more sensitive portion (though not the most sensitive) of the 
MF hearing range. Also, of the sources expected to result in take, they 
are used in a large portion of exercises (see Table 1 and Table 3). 
Most of the takes (98 percent) from the MF1 bin in the TMAA will result 
from received levels between 148 and 166 dB SPL. For the remaining 
active sonar bin types, the percentages are as follows: MF4 = 97 
percent between 130 and 148 dB SPL and MF5 = 99 percent between 100 and 
148 dB SPL. Given the levels they are exposed to and beaked whale 
sensitivity, some responses will be of a lower severity, but many will 
likely be considered moderate, but still of generally short duration.
    Research has shown that beaked whales are especially sensitive to 
the presence of human activity (Pirotta et al., 2012; Tyack et al., 
2011) and therefore have been assigned a lower harassment threshold, 
with lower received levels resulting in a higher percentage of 
individuals being harassed and a more distant distance cutoff (50 km 
for high source level, 25 km for moderate source level).
    Beaked whales have been documented to exhibit avoidance of human 
activity or respond to vessel presence (Pirotta et al., 2012). Beaked 
whales were observed to react negatively to survey vessels or low 
altitude aircraft by quick diving and other avoidance maneuvers, and 
none were observed to approach vessels (Wursig et al., 1998). Available 
information suggests that beaked whales likely have enhanced 
sensitivity to sonar sound, given documented incidents of stranding in 
conjunction with specific circumstances of MFAS use, although few 
definitive causal relationships between MFAS use and strandings have 
been documented (see Potential Effects of Specified Activities on 
Marine Mammals and their Habitat section). NMFS did not authorize 
mortality of beaked whales (or any other species or stocks) resulting 
from exposure to active sonar, as mortality is not anticipated for the 
reasons described in the Potential Effects of Specified Activities on 
Marine Mammals and Their Habitat section of the proposed rule (87 FR 
49656; August 11, 2022).
    Research and observations show that if beaked whales are exposed to 
sonar or other active acoustic sources, they may startle, break off 
feeding dives, and avoid the area of the sound source to levels of 157 
dB re: 1 [micro]Pa, or below (McCarthy et al., 2011). For example, 
after being exposed to 1-2 kHz upsweep naval sonar signals at a 
received SPL of 107 dB re 1 [mu]Pa, Northern bottlenose whales began 
moving in an unusually straight course, made a near 180[deg] turn away 
from the source, and performed the longest and deepest dive (94 min, 
2,339 m) recorded for this species (Miller et al., 2015). Wensveen et 
al. (2019) also documented avoidance behaviors in Northern bottlenose 
whales exposed to 1-2 kHz tonal sonar signals with SPLs ranging between 
117-126 dB re: 1 [micro]Pa, including interrupted diving behaviors, 
elevated swim speeds, directed movements away from the sound source, 
and cessation of acoustic signals throughout exposure periods. Acoustic 
monitoring during actual sonar exercises revealed some beaked whales 
continuing to forage at levels up to 157 dB re: 1 [micro]Pa (Tyack et 
al., 2011). Stimpert et al. (2014) tagged a Baird's beaked whale, which 
was subsequently exposed to simulated MFAS. Changes in the animal's 
dive behavior and locomotion were observed when received level reached 
127 dB re: 1 [mu]Pa. However, Manzano-Roth et al. (2013) found that for 
beaked whale dives that continued to occur during MFAS activity, 
differences from normal dive profiles and click rates were not detected 
with estimated received levels up to 137 dB re: 1 [micro]Pa while the 
animals were at depth during their dives. In research done at the 
Navy's fixed tracking range in the Bahamas, animals were observed to 
leave the immediate area of the Anti-Submarine Warfare training 
exercise (avoiding the sonar acoustic footprint at a distance where the 
received level was ``around 140 dB SPL,'' according to Tyack et al. 
(2011)), but return within a few days after the event ended (Claridge 
and Durban, 2009; McCarthy et al., 2011; Moretti et al., 2009, 2010; 
Tyack et al., 2010, 2011). Joyce et al. (2019) found that Blainville's 
beaked whales moved up to 68 km away from an Atlantic Undersea Test and 
Evaluation Center site and reduced time spent on deep dives after the 
onset of mid-frequency active sonar exposure; whales did not return to 
the site until 2-4 days after the exercises ended. Changes in acoustic 
activity have also been documented. For example, Blainville's beaked 
whales showed decreased group vocal periods after biannual multi-day 
Navy training activities (Henderson et al., 2016). Tyack et al. (2011) 
reported that, in reaction to sonar playbacks, most beaked whales 
stopped echolocating, made long slow ascent to the surface, and moved 
away from the sound. A similar behavioral response study conducted in 
Southern California waters during the 2010-2011 field season found that 
Cuvier's beaked whales exposed to MFAS displayed behavior ranging from 
initial orientation changes to avoidance responses characterized by 
energetic fluking and swimming away from the source (DeRuiter et al., 
2013b). However, the authors did not detect similar responses to 
incidental exposure to distant naval sonar exercises at comparable 
received levels, indicating that context of the exposures (e.g., source 
proximity, controlled source ramp-up) may have been a significant 
factor. The study itself found the results inconclusive and meriting 
further investigation. Falcone et al. (2017) however, documented that 
Cuvier's beaked whales had longer dives and surface durations after 
exposure to mid-frequency active sonar, with the longer surface 
intervals contributing to a longer interval between deep dives, a proxy 
for foraging disruption in this species. Cuvier's beaked whale 
responses suggested particular sensitivity to sound exposure consistent 
with results for Blainville's beaked whale.
    Populations of beaked whales and other odontocetes on the Bahamas 
and other Navy fixed ranges that have been operating for decades appear 
to be stable. Behavioral reactions (avoidance of the area of Navy 
activity) seem most likely in cases where beaked whales are exposed to 
anti-submarine sonar within a few tens of kilometers, especially for 
prolonged periods (a few hours or more) since this is one of the most 
sensitive marine mammal groups to anthropogenic sound of any species or 
group studied to date and research indicates beaked whales will leave 
an area where anthropogenic sound is present (De Ruiter et al., 2013; 
Manzano-Roth et al., 2013; Moretti et al., 2014; Tyack et al., 2011). 
Research involving tagged Cuvier's beaked whales in the SOCAL Range 
Complex reported on by Schorr et al. (2022) indicates year-round 
prolonged use of the Navy's training and testing area by these beaked 
whales and has documented movements in excess of hundreds of kilometers 
by some of those animals. Given that some of these animals may 
routinely move hundreds of kilometers as part of their normal pattern, 
leaving an area where sonar or other anthropogenic sound is present may 
have little, if any, cost to such an animal. Photo identification 
studies in the SOCAL Range Complex, have identified approximately 100 
Cuvier's beaked whale individuals with 40 percent having been seen in 
one or more prior years, with re-sightings up to

[[Page 684]]

7 years apart (Falcone and Schorr, 2014). These results indicate long-
term residency by individuals in an intensively used Navy training and 
testing area, which may also suggest a lack of long-term consequences 
as a result of exposure to Navy training and testing activities. More 
than 8 years of passive acoustic monitoring on the Navy's instrumented 
range west of San Clemente Island documented no significant changes in 
annual and monthly beaked whale echolocation clicks, with the exception 
of repeated fall declines likely driven by natural beaked whale life 
history functions (DiMarzio et al., 2018). Finally, results from 
passive acoustic monitoring estimated that regional Cuvier's beaked 
whale densities were higher than indicated by NMFS' broad scale visual 
surveys for the United States West Coast (Hildebrand and McDonald, 
2009).
    Below we compile and summarize the information that supports our 
determinations that the Navy's activities would not adversely affect 
any of the beaked whale stocks through effects on annual rates of 
recruitment or survival.
Baird's, Cuvier's, and Stejneger's Beaked Whales (Alaska Stocks)
    Baird's beaked whale, Cuvier's beaked whale, and Stejneger's beaked 
whale are not listed as endangered or threatened species under the ESA, 
and the 2019 Alaska SARs indicate that trend information is not 
available for any of the Alaska stocks. No BIAs for beaked whales have 
been identified in the GOA Study Area.
    As indicated in Table 45, no abundance estimates are available for 
any of the stocks. However, the ranges of all three stocks are large 
compared to the GOA Study Area (Cuvier's is the smallest, occupying all 
of the Gulf of Alaska, south of the Canadian border and west along the 
Aleutian Islands. Baird's range even farther south and Baird's and 
Stejneger's also cross north over the Aleutian Islands).
    Regarding abundance and distribution of these species in the 
vicinity of the TMAA, passive acoustic data indicate spatial overlap of 
all three beaked whales; however, detections are spatially offset, 
suggesting some level of habitat portioning in the Gulf of Alaska (Rice 
et al., 2019, 2020, 2021). Peaks in detections by Rice et al. (2021) 
were also temporally offset, with detections of Baird's beaked whale 
clicks peaking in winter at the slope and in spring at the seamounts. 
Rice et al. (2021) indicates Baird's beaked whales were highest in 
number at Quinn seamount, which overlaps with the southern edge of the 
TMAA, and therefore, a portion of this habitat is outside of the TMAA. 
Baumann Pickering et al. (2012b) did not acoustically detect Baird's 
beaked whales from July-October in the northern Gulf of Alaska 
(overlapping with the majority of the Navy's potential training 
period), while acoustic detections from November-January suggest that 
Baird's beaked whales may winter in this area. Rice et al. (2021) 
reported the highest detections of Baird's beaked whales within the 
TMAA during the spring in the portion of the TMAA that is farther 
offshore, with lowest detections in the summer and an increase in 
detections on the continental slope in the winter, indicating that the 
whales are either not producing clicks in the summer or they are 
migrating farther north or south to feed or mate during this time.
    Data from a satellite-tagged Baird's beaked whale off Southern 
California recently documented movement north along the shelf-edge for 
more than 400 nmi over a six-and-a-half-day period (Schorr et al., 
Unpublished). If that example is reflective of more general behavior, 
Baird's beaked whales present in the TMAA may have much larger home 
ranges than the waters bounded by the TMAA, reducing the potential for 
repeated takes of individuals.
    Regarding Stejneger's beaked whale, passive acoustic monitoring 
detected the whales most commonly at the slope and offshore in the TMAA 
(Rice et al., 2021; Rice et al., 2018b; Rice et al., 2020). At the 
slope, Stejneger's beaked whale detections peaked in fall (Rice et al., 
2021). Rice et al. (2021) notes that to date, there have been no 
documented sightings of Stejneger's beaked whales that were 
simultaneous with recording of vocalizations, which is necessary to 
confirm the vocalizations were produced by the species, and therefore, 
detections should be interpreted with caution. Baumann-Pickering et al. 
(2012b) recorded acoustic signals believed to be produced by 
Stejneger's beaked whales (based on frequency characteristics, 
interpulse interval, and geographic location; Baumann-Pickering et al., 
2012a) almost weekly from July 2011 to February 2012 in the northern 
Gulf of Alaska.
    Regarding Cuvier's beaked whale, passive acoustic monitoring at 
five sites in the TMAA (Rice et al., 2015, 2018b, 2019, 2020, 2021) has 
intermittently detected Cuvier's beaked whale vocalizations in low 
numbers in every month except April, although there are generally 
multiple months in any given year where no detections are made.
    Regarding the magnitude of takes by Level B harassment (TTS and 
behavioral disturbance), the anticipated takes would occur within a 
small portion of the stocks' ranges (including that none of the stocks 
are expected to occur in the far western edge of the TMAA; U.S. 
Department of the Navy, 2021) and will occur within the 21-day window 
of the annual activities. In consideration of these factors and the 
passive acoustic monitoring data described in this section, which 
indicates relatively low beaked whale presence in the TMAA during the 
Navy's planned training period, it is likely that a portion of the 
stocks would be taken, and a subset of them may be taken on a few days, 
with no indication that these days will be sequential.
    Regarding the severity of those individual takes by Level B 
harassment by behavioral disturbance, we have explained that the 
duration of any exposure is expected to be between minutes and hours 
(i.e., relatively short) and the received sound levels largely below 
166 dB, though with beaked whales, which are considered somewhat more 
sensitive, this could mean that some individuals would leave preferred 
habitat for a day (i.e., moderate level takes). However, while 
interrupted feeding bouts are a known response and concern for 
odontocetes, we also know that there are often viable alternative 
habitat options nearby. Regarding the severity of TTS takes 
(anticipated for Cuvier's and Stejneger's beaked whales only), they are 
expected to be low-level, of short duration, and mostly not in a 
frequency band that would be expected to interfere with beaked whale 
communication or other important low-frequency cues. Therefore, the 
associated lost opportunities and capabilities are not at a level that 
will impact reproduction or survival. As mentioned earlier in the 
odontocete overview, we anticipate more severe effects from takes when 
animals are exposed to higher received levels or sequential days of 
impacts.
    Altogether, none of these species are ESA-listed, only a portion of 
the stocks are anticipated to be impacted, and any individual beaked 
whale is likely to be disturbed at a moderate or sometimes low level. 
This low magnitude and moderate to lower severity of harassment effects 
is not expected to result in impacts on individual reproduction or 
survival, let alone have impacts on annual rates of recruitment or 
survival of this stock. No mortality, serious injury, or Level A 
harassment is anticipated or authorized. For these reasons, we have 
determined, in consideration of all of the effects of the Navy's 
activities combined, that the authorized take will have a negligible

[[Page 685]]

impact on the Alaska stocks of beaked whales.

Dolphins and Small Whales

    This section builds on the broader odontocete discussion above and 
brings together the discussion of the different types and amounts of 
take that different dolphin and small whale species and stocks are 
likely to incur, the applicable mitigation, and the status of the 
species and stocks to support the negligible impact determinations for 
each species or stock. For all dolphin and small whale stocks discussed 
here, no mortality or Level A harassment is anticipated or authorized.
    In Table 46 below for dolphins and small whales, we indicate the 
total annual numbers of take by Level A harassment and Level B 
harassment, and a number indicating the instances of total take as a 
percentage of abundance.

    Table 46--Annual Estimated Takes by Level B Harassment and Level A Harassment for Dolphins and Small Whales in the TMAA and Number Indicating the
                                           Instances of Total Take as a Percentage of Species/Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Instances of indicated types of incidental
                                                                              take \1\
                                                          ------------------------------------------------                                Instances of
                                                                 Level B harassment            Level A       Total     Abundance (NMFS    total take as
              Species                       Stock         --------------------------------   harassment      takes        SARs) \2\       percentage of
                                                                            TTS (may also ----------------                                  abundance
                                                             Behavioral        include
                                                             disturbance    disturbance)         PTS
--------------------------------------------------------------------------------------------------------------------------------------------------------
Killer whale......................  Eastern North Pacific              64              17               0         81               300              27.0
                                     Offshore.
                                    Eastern North Pacific             119              24               0        143               587              24.4
                                     Gulf of Alaska,
                                     Aleutian Islands,
                                     and Bering Sea
                                     Transient.
Pacific white-sided dolphins......  North Pacific........           1,102             472               0      1,574            26,880               5.9
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate
  individuals, especially for disturbance.
\2\ Presented in the 2021 SARs or most recent SAR.

    As described above, the large majority of Level B harassment by 
behavioral disturbance to odontocetes, and thereby dolphins and small 
whales, from hull-mounted sonar (MFAS) in the TMAA will result from 
received levels between 160 and 172 dB SPL. Therefore, the majority of 
takes by Level B harassment are expected to be in the form of low to 
occasionally moderate responses of a generally shorter duration. As 
mentioned earlier in this section, we anticipate more severe effects 
from takes when animals are exposed to higher received levels or for 
longer durations. Occasional milder occurrences of Level B harassment 
by behavioral disturbance are unlikely to cause long-term consequences 
for individual animals, much less have any effect on annual rates of 
recruitment or survival. No mortality, serious injury, or Level A 
harassment is expected or authorized.
    Research and observations show that if delphinids are exposed to 
sonar or other active acoustic sources they may react in a number of 
ways depending on their experience with the sound source and what 
activity they are engaged in at the time of the acoustic exposure. 
Delphinids may not react at all until the sound source is approaching 
within a few hundred meters to within a few kilometers depending on the 
environmental conditions and species. Some dolphin species (the more 
surface-dwelling taxa--typically those with ``dolphin'' in the common 
name, such as bottlenose dolphins, spotted dolphins, spinner dolphins, 
rough-toothed dolphins, etc., but not Risso's dolphin), especially 
those residing in more industrialized or busy areas, have demonstrated 
more tolerance for disturbance and loud sounds and many of these 
species are known to approach vessels to bow-ride. These species are 
often considered generally less sensitive to disturbance. Dolphins and 
small whales that reside in deeper waters and generally have fewer 
interactions with human activities are more likely to demonstrate more 
typical avoidance reactions and foraging interruptions as described 
above in the odontocete overview.
    Below we compile and summarize the information that supports our 
determinations that the Navy's activities will not adversely affect any 
of the dolphins and small whales through effects on annual rates of 
recruitment or survival.
Killer Whales (Eastern North Pacific Offshore; Eastern North Pacific 
Gulf of Alaska, Aleutian Islands, and Bering Sea Transient)
    No killer whale stocks in the TMAA are listed as DPSs under the 
ESA, and no BIAs for killer whales have been identified in the GOA 
Study Area. The Eastern North Pacific Offshore stock is reported as 
``stable,'' and the population trend of the Eastern North Pacific Gulf 
of Alaska, Aleutian Islands, and Bering Sea Transient stock is unknown.
    Regarding the magnitude of takes by Level B harassment (TTS and 
behavioral disturbance), the number of estimated total instances of 
take compared to the abundance is 27 percent for the Eastern North 
Pacific Offshore stock and 24 percent for the Eastern North Pacific 
Gulf of Alaska, Aleutian Islands, and Bering Sea Transient stock. This 
information indicates that only a portion of each stock is likely 
impacted, with those individuals disturbed on likely one, but not more 
than a few non-sequential days within the 21 days per year. Regarding 
the severity of those individual takes by Level B harassment by 
behavioral disturbance, we have explained that the duration of any 
exposure is expected to be between minutes and hours (i.e., relatively 
short) and the received sound levels largely below 172 dB (i.e., of a 
lower, to occasionally moderate, level and less likely to evoke a 
severe response). Regarding the severity of TTS takes, they are 
expected to be low-level, of short duration, and mostly not in a 
frequency band that would be expected to interfere with killer whale 
communication or other important low-frequency cues. Therefore, the 
associated lost opportunities and capabilities are not at a level that 
will impact reproduction or survival.
    Altogether, these killer whale stocks are not listed under the ESA. 
The Eastern North Pacific Offshore stock is reported as ``stable,'' and 
the population trend of the Eastern North Pacific Gulf

[[Page 686]]

of Alaska, Aleutian Islands, and Bering Sea Transient stock is unknown. 
Only a portion of these killer whale stocks is anticipated to be 
impacted, and any individual is likely to be disturbed at a low-
moderate level, with the taken individuals likely exposed on one day 
but not more than a few non-sequential days within a year. This low 
magnitude and severity of harassment effects is unlikely to result in 
impacts on individual reproduction or survival, let alone have impacts 
on annual rates of recruitment or survival of either of the stocks. No 
mortality or Level A harassment is anticipated or authorized for either 
of the stocks. For these reasons, we have determined, in consideration 
of all of the effects of the Navy's activities combined, that the 
authorized take will have a negligible impact on these killer whale 
stocks.
Pacific White-Sided Dolphins (North Pacific Stock)
    Pacific white-sided dolphins are not listed under the ESA and the 
current population trend of the North Pacific stock is unknown. No BIAs 
for this stock have been identified in the GOA Study Area.
    Regarding the magnitude of takes by Level B harassment (TTS and 
behavioral disturbance), the number of estimated total instances of 
take compared to the abundance is 6 percent. Given the number of takes, 
only a small portion of the stock is likely impacted, and individuals 
are likely disturbed between one and a few days, most likely non-
sequential, within a year. Regarding the severity of those individual 
takes by Level B harassment by behavioral disturbance, we have 
explained that the duration of any exposure is expected to be between 
minutes and hours (i.e., relatively short) and the received sound 
levels largely below 172 dB (i.e., of a lower, to occasionally 
moderate, level and less likely to evoke a severe response). However, 
while interrupted feeding bouts are a known response and concern for 
odontocetes, we also know that there are often viable alternative 
habitat options nearby. Regarding the severity of TTS takes, they are 
expected to be low-level, of short duration, and mostly not in a 
frequency band that would be expected to interfere with dolphin 
communication or other important low-frequency cues. Therefore, the 
associated lost opportunities and capabilities are not at a level that 
will impact reproduction or survival.
    Altogether, though the status of this stock is unknown, this stock 
is not listed under the ESA. Any individual is likely to be disturbed 
at a low-moderate level, and those individuals likely disturbed on one 
to a few non-sequential days within a year. This low magnitude and 
severity of harassment effects is not expected to result in impacts on 
individual reproduction or survival, let alone have impacts on annual 
rates of recruitment or survival of this stock. No mortality, serious 
injury, or Level A harassment is anticipated or authorized. For these 
reasons, we have determined, in consideration of all of the effects of 
the Navy's activities combined, that the authorized take will have a 
negligible impact on the North Pacific stock of Pacific white-sided 
dolphins.

Dall's Porpoise (Alaska Stock)

    This section builds on the broader odontocete discussion above and 
brings together the discussion of the different types and amounts of 
take that this porpoise stock would likely incur, the applicable 
mitigation, and the status of the stock to support the negligible 
impact determination.
    In Table 47 below for Dall's porpoise, we indicate the total annual 
numbers of take by Level A harassment and Level B harassment, and a 
number indicating the instances of total take as a percentage of 
abundance.

  Table 47--Annual Estimated Takes by Level B Harassment and Level A Harassment for Dall's Porpoise in the TMAA and Number Indicating the Instances of
                                                  Total Take as a Percentage of Species/Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Instances of indicated types of incidental
                                                                              take \1\
                                                          ------------------------------------------------                                Instances of
                                                                 Level B harassment            Level A       Total     Abundance (NMFS    total take as
              Species                       Stock         --------------------------------   harassment      takes        SARs) \2\       percentage of
                                                                            TTS (may also ----------------                                  abundance
                                                             Behavioral        include
                                                             disturbance    disturbance)         PTS
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dall's porpoise...................  Alaska...............             348           8,939              64      9,351            83,400              11.2
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated impacts are based on the maximum number of activities in a given year under the Specified Activity. Not all takes represent separate
  individuals, especially for disturbance.
\2\ Presented in the 2021 SARs or most recent SAR.

    Dall's porpoise is not listed under the ESA and the current 
population trend for the Alaska stock is unknown. No BIAs for Dall's 
porpoise have been identified in the GOA Study Area.
    While harbor porpoises have been observed to be especially 
sensitive to human activity, the same types of responses have not been 
observed in Dall's porpoises. Dall's porpoises are typically notably 
longer than, and weigh more than twice as much as harbor porpoises, 
making them generally less likely to be preyed upon and likely 
differentiating their behavioral repertoire somewhat from harbor 
porpoises. Further, they are typically seen in large groups and feeding 
aggregations, or exhibiting bow-riding behaviors, which is very 
different from the group dynamics observed in the more typically 
solitary, cryptic harbor porpoises, which are not often seen bow-
riding. For these reasons, Dall's porpoises are not treated as an 
especially sensitive species (versus harbor porpoises which have a 
lower behavioral harassment threshold and more distant cutoff) but, 
rather, are analyzed similarly to other odontocetes (with takes from 
the sonar bin in the TMAA resulting from the same received levels 
reported in the Odontocete section above). Therefore, the majority of 
Level B harassment by behavioral disturbance is expected to be in the 
form of milder responses compared to higher level exposures. As 
mentioned earlier in this section, we anticipate more severe effects 
from takes when animals are exposed to higher received levels.
    We note that Dall's porpoise, as a HF-sensitive species, has a 
lower PTS threshold than other groups and therefore is generally more 
likely to experience TTS and PTS, and potentially occasionally to a 
greater degree, and NMFS accordingly has evaluated and authorized 
higher numbers. Also, however, regarding PTS from sonar exposure, 
porpoises are still likely to avoid sound levels that would cause 
higher levels of TTS (greater than 20 dB) or PTS. Therefore, even 
though the number of TTS takes are higher than for other odontocetes, 
any PTS is

[[Page 687]]

expected to be at a lower to occasionally moderate level and for all of 
the reasons described above, TTS and PTS takes are not expected to 
impact reproduction or survival of any individual.
    Regarding the magnitude of takes by Level B harassment (TTS and 
behavioral disturbance), the number of estimated total instances of 
take compared to the abundance is 11 percent. This indicates that only 
a small portion of this stock is likely to be impacted, and a subset of 
those individuals will likely be taken on no more than a few non-
sequential days within a year. Regarding the severity of those 
individual takes by Level B harassment by behavioral disturbance, we 
have explained that the duration of any exposure is expected to be 
between minutes and hours (i.e., relatively short) and the received 
sound levels largely below 172 dB (i.e., of a lower, to occasionally 
moderate, level and less likely to evoke a severe response). Regarding 
the severity of TTS takes, they are expected to be low-level, of short 
duration, and mostly not in a frequency band that would be expected to 
interfere with communication or other important low-frequency cues. 
Therefore, the associated lost opportunities and capabilities are not 
at a level that will impact reproduction or survival.
    For the same reasons explained above for TTS (low to occasionally 
moderate level and the likely frequency band), while a small permanent 
loss of hearing sensitivity may include some degree of energetic costs 
for compensating or may mean some small loss of opportunities or 
detection capabilities, the estimated annual takes by Level A 
harassment by PTS for this stock (64 takes) are unlikely to impact 
behaviors, opportunities, or detection capabilities to a degree that 
will interfere with reproductive success or survival of any 
individuals.
    Altogether, the status of the Alaska stock of Dall's porpoise is 
unknown, however Dall's porpoise are not listed as endangered or 
threatened under the ESA. Only a small portion of this stock is likely 
to be impacted, any individual is likely to be disturbed at a low-
moderate level, and a subset of taken individuals will likely be taken 
on a few non-sequential days within a year. This low magnitude and 
severity of Level B harassment effects is not expected to result in 
impacts on individual reproduction or survival, much less annual rates 
of recruitment or survival. Some individuals (64 annually) could be 
taken by PTS of likely low to occasionally moderate severity. A small 
permanent loss of hearing sensitivity (PTS) may include some degree of 
energetic costs for compensating or may mean some small loss of 
opportunities or detection capabilities, but at the expected scale the 
estimated takes by Level A harassment by PTS for this stock are 
unlikely, alone or in combination with the Level B harassment take by 
behavioral disturbance and TTS, to impact behaviors, opportunities, or 
detection capabilities to a degree that will interfere with 
reproductive success or survival of any individuals, let alone have 
impacts on annual rates of recruitment or survival of this stock. No 
mortality or serious injury and no Level A harassment from non-auditory 
tissue damage is anticipated or authorized. For these reasons, we have 
determined, in consideration of all of the effects of the Navy's 
activities combined, that the authorized take will have a negligible 
impact on the Alaska stock of Dall's porpoise.
Pinnipeds
    This section builds on the broader discussion above and brings 
together the discussion of the different types and amounts of take that 
different species and stocks will likely incur, the applicable 
mitigation, and the status of the species and stocks to support the 
negligible impact determinations for each species or stock. We have 
described (earlier in this section) the unlikelihood of any masking 
having effects that will impact the reproduction or survival of any of 
the individual marine mammals affected by the Navy's activities. We 
have also described above in the Potential Effects of Specified 
Activities on Marine Mammals and their Habitat section of the proposed 
rule that the specified activities would not have adverse or long-term 
impacts on marine mammal habitat, and therefore the unlikelihood of any 
habitat impacts affecting the reproduction or survival of any of the 
individual marine mammals affected by the Navy's activities. For 
pinnipeds, there is no mortality or serious injury and no Level A 
harassment from non-auditory tissue damage from sonar or explosives 
anticipated or authorized for any species.
    Regarding behavioral disturbance, research and observations show 
that pinnipeds in the water may be tolerant of anthropogenic noise and 
activity (a review of behavioral reactions by pinnipeds to impulsive 
and non-impulsive noise can be found in Richardson et al. (1995) and 
Southall et al. (2007)). Available data, though limited, suggest that 
exposures between approximately 90 and 140 dB SPL do not appear to 
induce strong behavioral responses in pinnipeds exposed to non-pulse 
sounds in water (Costa et al., 2003; Jacobs and Terhune, 2002; 
Kastelein et al., 2006c). Based on the limited data on pinnipeds in the 
water exposed to multiple pulses (small explosives, impact pile 
driving, and seismic sources), exposures in the approximately 150 to 
180 dB SPL range generally have limited potential to induce avoidance 
behavior in pinnipeds (Blackwell et al., 2004; Harris et al., 2001; 
Miller et al., 2004). If pinnipeds are exposed to sonar or other active 
acoustic sources they may react in a number of ways depending on their 
experience with the sound source and what activity they are engaged in 
at the time of the acoustic exposure. Pinnipeds may not react at all 
until the sound source is approaching within a few hundred meters and 
then may alert, ignore the stimulus, change their behaviors, or avoid 
the immediate area by swimming away or diving. Effects on pinnipeds 
that are taken by Level B harassment in the TMAA, on the basis of 
reports in the literature as well as Navy monitoring from past 
activities, will likely be limited to reactions such as increased 
swimming speeds, increased surfacing time, or decreased foraging (if 
such activity were occurring). Most likely, individuals will simply 
move away from the sound source and be temporarily displaced from those 
areas, or not respond at all, which will have no effect on reproduction 
or survival. While some animals may not return to an area, or may begin 
using an area differently due to training activities, most animals are 
expected to return to their usual locations and behavior. Given their 
documented tolerance of anthropogenic sound (Richardson et al., 1995 
and Southall et al., 2007), repeated exposures of individuals of any of 
these species to levels of sound that may cause Level B harassment are 
unlikely to result in hearing impairment or to significantly disrupt 
(through direct disturbance or opportunities lost during TTS) foraging 
or resting behaviors in a manner that would reduce reproductive success 
or health. Thus, even repeated Level B harassment of some small subset 
of individuals of an overall stock is unlikely to result in any 
significant realized decrease in fitness to those individuals that 
would result in any adverse impact on rates of recruitment or survival 
for the stock as a whole.
    While no take of Steller sea lion is anticipated or authorized, we 
note that the GOA Study Area boundary was intentionally designed to 
avoid ESA-designated Steller sea lion critical habitat.

[[Page 688]]

    All the pinniped species discussed in this section will benefit 
from the procedural mitigation measures described earlier in the 
Proposed Mitigation Measures section.
    In Table 48 below for pinnipeds, we indicate the total annual 
numbers of take by Level A harassment and Level B harassment, and a 
number indicating the instances of total take as a percentage of 
abundance.

  Table 48--Annual Estimated Takes by Level B Harassment and Level A Harassment for Pinnipeds in the TMAA and Number Indicating the Instances of Total
                                                     Take as a Percentage of Species/Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Instances of indicated types of incidental
                                                                              take \1\
                                                          ------------------------------------------------                                Instances of
                                                                 Level B harassment            Level A       Total     Abundance (NMFS    total take as
              Species                       Stock         --------------------------------   harassment      takes        SARs) \2\       percentage of
                                                                            TTS (may also ----------------                                  abundance
                                                             Behavioral        include
                                                             disturbance    disturbance)         PTS
--------------------------------------------------------------------------------------------------------------------------------------------------------
Northern fur seal.................  Eastern Pacific......           2,972              31               0      3,003           626,618                <1
                                    California...........              60               1               0         61            14,050                <1
Northern elephant seal............  California...........             904           1,643               8      2,555           187,386               1.3
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated impacts are based on the maximum number of activities in a given year under the specified activity. Not all takes represent separate
  individuals, especially for disturbance.
\2\ Presented in the 2021 SARs or most recent SAR.

    The majority of takes by harassment of pinnipeds in the TMAA are 
caused by sources from the MFAS bin (which includes hull-mounted sonar) 
because they are high level sources at a frequency (1-10 kHz) which 
overlaps the most sensitive portion of the pinniped hearing range, and 
of the sources expected to result in take, they are used in a large 
portion of exercises (see Table 1 and Table 3). Most of the takes (>99 
percent) from the MF1 bin in the TMAA would result from received levels 
between 166 and 178 dB SPL. For the remaining active sonar bin types, 
the percentages are as follows: MF4 = 97 percent between 148 and 172 dB 
SPL and MF5 = 99 percent between 130 and 160 dB SPL. Given the levels 
they are exposed to and pinniped sensitivity, most responses would be 
of a lower severity, with only occasional responses likely to be 
considered moderate, but still of generally short duration.
    As mentioned earlier in this section, we anticipate more severe 
effects from takes when animals are exposed to higher received levels. 
Occasional milder takes by Level B harassment by behavioral disturbance 
are unlikely to cause long-term consequences for individual animals or 
populations, especially when they are not expected to be repeated over 
sequential multiple days. For all pinnipeds except Northern elephant 
seals, no take is expected to occur from explosives. For Northern 
elephant seals, harassment takes from explosives (behavioral 
disturbance, TTS, and PTS) comprise a very small fraction of those 
caused by exposure to active sonar.
    Because the majority of harassment takes of pinnipeds result from 
narrowband sources in the range of 1-10 kHz, the vast majority of 
threshold shift caused by Navy sonar sources will typically occur in 
the range of 2-20 kHz. This frequency range falls within the range of 
pinniped hearing, however, pinniped vocalizations typically span a 
somewhat lower range than this (<0.2 to 10 kHz) and threshold shift 
from active sonar will often be in a narrower band (reflecting the 
narrower band source that caused it), which means that TTS incurred by 
pinnipeds will typically only interfere with communication within a 
portion of a pinniped's range (if it occurred during a time when 
communication with conspecifics was occurring). As discussed earlier, 
it would only be expected to be of a short duration and relatively 
small degree. Many of the other critical sounds that serve as cues for 
navigation and prey (e.g., waves, fish, invertebrates) occur below a 
few kHz, which means that detection of these signals will not be 
inhibited by most threshold shifts either. The very low number of takes 
by threshold shifts that might be incurred by individuals exposed to 
explosives would likely be lower frequency (5 kHz or less) and spanning 
a wider frequency range, which could slightly lower an individual's 
sensitivity to navigational or prey cues, or a small portion of 
communication calls, for several minutes to hours (if temporary) or 
permanently.
    Neither of these species are ESA-listed and the SAR indicates that 
the status of the Eastern Pacific stock of Northern fur seal is stable, 
the California stock of Northern fur seal is increasing, and the 
California stock of Northern elephant seal is increasing. BIAs have not 
been identified for pinnipeds.
    Regarding the magnitude of takes by Level B harassment (TTS and 
behavioral disturbance) for the Eastern Pacific and California stocks 
of Northern fur seals, the estimated instances of takes as compared to 
the stock abundance is <1 percent for each stock. For the California 
stock of Northern elephant seal, the number of estimated total 
instances of take compared to the abundance is 1 percent. This 
information indicates that only a very small portion of individuals in 
these stocks are likely impacted, particularly given the large ranges 
of the stocks. Impacted individuals would be disturbed on likely one, 
but not more than a few non-sequential days within a year.
    Regarding the severity of those individual takes by Level B 
harassment by behavioral disturbance for all pinniped stocks, we have 
explained that the duration of any exposure is expected to be between 
minutes and hours (i.e., relatively short) and the received sound 
levels largely below 178 dB, which is considered a relatively low to 
occasionally moderate level for pinnipeds.
    Regarding the severity of TTS takes, they are expected to be low-
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. Therefore, the associated lost opportunities and 
capabilities are not at a level that will impact reproduction or 
survival. For these same reasons (low level and frequency band), while 
a small permanent loss of hearing sensitivity may include some degree 
of energetic costs for compensating or may mean some small loss of 
opportunities or detection capabilities, the 8 estimated Level A 
harassment takes by PTS for the California stock of Northern elephant 
seal would be unlikely to impact behaviors, opportunities, or detection 
capabilities to a degree that will

[[Page 689]]

interfere with reproductive success or survival of any individuals.
    Altogether, none of these species are listed under the ESA, and the 
SARs indicate that the status of the Eastern Pacific stock of Northern 
fur seal is stable, the California stock of Northern fur seal is 
increasing, and the California stock of Northern elephant seal is 
increasing. No mortality or serious injury and no Level A harassment 
from non-auditory tissue damage for pinnipeds is anticipated or 
authorized. Level A harassment by PTS is only anticipated for the 
California stock of Northern elephant seal (8 takes by Level A 
harassment). For all three pinniped stocks, only a small portion of the 
stocks are anticipated to be impacted and any individual is likely to 
be disturbed at a low-moderate level. This low magnitude and severity 
of harassment effects is not expected to result in impacts on 
individual reproduction or survival, let alone have impacts on annual 
rates of recruitment or survival of these stocks. For these reasons, in 
consideration of all of the effects of the Navy's activities combined, 
we have determined that the authorized take would have a negligible 
impact on all three stocks of pinnipeds.

Determination

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

Subsistence Harvest of Marine Mammals

    In order to issue an incidental take authorization, NMFS must find 
that the specified activity will not have an ``unmitigable adverse 
impact'' on the subsistence uses by Alaska Natives. NMFS has defined 
``unmitigable adverse impact'' in 50 CFR 216.103 as an impact resulting 
from the specified activity: (1) That is likely to reduce the 
availability of the species to a level insufficient for a harvest to 
meet subsistence needs by: (i) Causing the marine mammals to abandon or 
avoid hunting areas; (ii) Directly displacing subsistence users; or 
(iii) Placing physical barriers between the marine mammals and the 
subsistence hunters; and (2) That cannot be sufficiently mitigated by 
other measures to increase the availability of marine mammals to allow 
subsistence needs to be met.
    When applicable, NMFS must prescribe means of effecting the least 
practicable adverse impact on the availability of the species or stocks 
for subsistence uses. As discussed in the Mitigation Measures section, 
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 on the availability of species or stocks for 
subsistence uses, and (2) the practicability of the measure(s) for 
applicant implementation.
    The Navy has met with and will continue to engage in meaningful 
consultation and communication with several federally recognized Alaska 
Native tribes that have traditional marine mammal harvest areas in the 
GOA (though, as noted below, these areas do not overlap directly with 
the GOA Study Area). Further, the Navy will continue to keep the Tribes 
informed of the timeframes of future joint training exercises.
    To our knowledge, subsistence hunting of marine mammals does not 
occur in the GOA Study Area where training activities would occur. To 
date, neither the Navy nor NMFS have received correspondence from 
Alaska Native groups regarding subsistence use, or any other concern 
with the MMPA rulemaking and authorizations. As described below in the 
Tribal Engagement section, NMFS requested input from Tribes on its 
proposed regulations to govern the take of marine mammals incidental to 
the U.S. Navy Training Activities in the Gulf of Alaska Study Area (87 
FR 49656; August 11, 2022), and as part of that request, NMFS 
specifically requested feedback on whether the proposed rule raised any 
concerns regarding effects on the Tribe or potential impacts to the 
Tribe's subsistence uses of marine mammals.
    The TMAA portion of the GOA Study Area is located over 12 nmi from 
shore with the nearest inhabited land being the Kenai Peninsula (24 nmi 
from the TMAA portion of the GOA Study Area). The landward border of 
the WMA portion of the GOA Study Area is generally farther offshore 
than the TMAA. The WMA is approximately 45 nmi (84 km) from Kodiak (the 
border's closest point to land), and approximately 117 nmi (216 km) 
from Chignik on the Alaska Peninsula (the border's farthest point from 
land). Information provided by Tribes in previous conversations with 
the Navy, and according to Alaska Department of Fish and Game (1995), 
indicates that harvest of pinnipeds occurs nearshore, and the Tribes do 
not use the GOA Study Area for subsistence hunting of marine mammals. 
The TMAA portion of the GOA Study Area is the closest to the area of 
nearshore subsistence harvest conducted by the Sun'aq Tribe of Kodiak, 
the Native Village of Eyak, and the Yakutat Tlingit Tribe (Alaska 
Department of Fish and Game, 1995). The WMA is offshore of subsistence 
harvest areas that occur in Unalaska, Akutan, False Pass, Sand Point, 
and King Cove (Alaska Department of Fish and Game, 1997). The Tribes 
listed above harvest harbor seals and sea lions (Alaska Department of 
Fish and Game, 1995, 1997).
    In addition to the distance between subsistence hunting areas and 
the GOA Study Area, which will ensure that the Navy's activities do not 
displace subsistence users or place physical barriers between the 
marine mammals and the subsistence hunters, there is no reason to 
believe that any behavioral disturbance or limited TTS or PTS of 
pinnipeds that occurs offshore in the GOA Study Area would affect their 
subsequent behavior in a manner that would interfere with subsistence 
uses should those pinnipeds later interact with hunters, particularly 
given that neither harbor seals, Steller sea lions, or California sea 
lions are expected to be taken by the Navy's training activities. The 
specified activity will be a continuation of the types of training 
activities that have been ongoing for more than a decade, and as 
discussed in the 2011 GOA FEIS/OEIS and 2016 GOA FSEIS/OEIS, no impacts 
on traditional subsistence practices or resources are predicted to 
result from the specified activity.
    Based on the information above, NMFS has determined that the total 
taking of affected species or stocks will not have an unmitigable 
adverse impact on the availability of the species or stocks for taking 
for subsistence purposes.

Tribal Engagement

    NMFS invited Tribes in the Gulf of Alaska region to a virtual 
Tribal engagement meeting on September 20, 2022 to seek Tribal input on 
the proposed regulations to govern the take of marine mammals 
incidental to the U.S. Navy Training Activities in the Gulf of Alaska 
Study Area (87 FR 49656; August 11, 2022). One Tribe attended the 
meeting. NMFS gave a presentation on the proposed regulations and 
invited the Tribe to ask questions and provide recommendations. NMFS 
specifically requested feedback on whether the proposed rule raised any 
concerns regarding effects on the Tribe or

[[Page 690]]

potential impacts to the Tribe's subsistence uses of marine mammals, 
whether the Tribe had any recommendations for modifications to NMFS' 
action, and whether the Tribe had any additional feedback on the 
proposed rule. The Tribe did not have questions or provide 
recommendations or feedback during the meeting. NMFS invited the Tribe 
to provide written comments following the meeting, but did not receive 
written comments.

Classification

Endangered Species Act

    There are eight marine mammal species under NMFS jurisdiction that 
are listed as endangered or threatened under the ESA (16 U.S.C. 1531 et 
seq.) with confirmed or possible occurrence in the GOA Study Area: 
North Pacific right whale, humpback whale (Mexico, Western North 
Pacific, and Central America DPSs), blue whale, fin whale, sei whale, 
gray whale (Western North Pacific DPS), sperm whale, and Steller sea 
lion (Western DPS). The humpback whale has critical habitat recently 
designated under the ESA in the TMAA portion of the GOA Study Area (86 
FR 21082; April 21, 2021). As discussed previously, the GOA Study Area 
boundaries were intentionally designed to avoid ESA-designated critical 
habitat for Steller sea lions.
    The Navy consulted with NMFS pursuant to section 7 of the ESA for 
GOA Study Area activities, and NMFS also consulted internally on the 
promulgation of this rule and the issuance of an LOA under section 
101(a)(5)(A) of the MMPA. NMFS issued a biological opinion concluding 
that the promulgation of the rule and issuance of a subsequent LOA are 
not likely to jeopardize the continued existence of threatened and 
endangered species under NMFS' jurisdiction and are not likely to 
result in the destruction or adverse modification of designated or 
proposed critical habitat in the GOA Study Area. The biological opinion 
is available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.

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 evaluate our proposed actions and alternatives with respect 
to potential impacts on the human environment. NMFS participated as a 
cooperating agency on the 2022 GOA FSEIS/OEIS, which was published on 
September 2, 2022 (87 FR 54213), and is available at https://www.goaeis.com/. In accordance with 40 CFR 1506.3, NMFS independently 
reviewed and evaluated the 2022 GOA FSEIS/OEIS and determined that it 
is adequate and sufficient to meet our responsibilities under NEPA for 
the issuance of this rule and associated LOA. NMFS therefore, has 
adopted the 2022 GOA FSEIS/OEIS. NMFS has prepared a separate Record of 
Decision. NMFS' Record of Decision for adoption of the 2022 GOA FSEIS/
OEIS and issuance of this final rule and subsequent LOAs can be found 
at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.

Executive Order 12866

    The Office of Management and Budget has determined that this rule 
is not significant for purposes of Executive Order 12866.

Regulatory Flexibility Act

    Pursuant to the Regulatory Flexibility Act (RFA; 5 U.S.C. 601 et 
seq.), the Chief Counsel for Regulation of the Department of Commerce 
has certified to the Chief Counsel for Advocacy of the Small Business 
Administration during the proposed rule stage that this action would 
not have a significant economic impact on a substantial number of small 
entities. The factual basis for the certification was published in the 
proposed rule and is not repeated here. No comments were received 
regarding this certification. As a result, a regulatory flexibility 
analysis was not required and none was prepared.

List of Subjects in 50 CFR Part 218

    Exports, Fish, Imports, Incidental take, Indians, Labeling, Marine 
mammals, Navy, Penalties, Reporting and recordkeeping requirements, 
Seafood, Sonar, Transportation.

    Dated: December 19, 2022.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, National Marine 
Fisheries Service.

    For reasons set forth in the preamble, 50 CFR part 218 is amended 
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., unless otherwise noted.

0
2. Add subpart P to read as follows:
Subpart P--Taking and Importing Marine Mammals; U.S. Navy Training 
Activities in the Gulf of Alaska Study Area
Sec.
218.150 Specified activity and geographical region.
218.151 Effective dates and definitions.
218.152 Permissible methods of taking.
218.153 Prohibitions.
218.154 Mitigation requirements.
218.155 Requirements for monitoring and reporting.
218.156 Letters of Authorization.
218.157 Renewals and modifications of Letters of Authorization.
218.158 [Reserved]

Subpart P--Taking and Importing Marine Mammals; U.S. Navy Training 
Activities in the Gulf of Alaska Study Area


Sec.  218.150   Specified activity and geographical region.

    (a) Regulations in this subpart apply only to the U.S. Navy (Navy) 
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 Gulf of Alaska (GOA) Study Area is entirely at sea and is 
comprised of three areas: a TMAA, a warning area, and the WMA located 
south and west of the TMAA. The TMAA and WMA are temporary areas 
established within the GOA for ships, submarines, and aircraft to 
conduct training activities. The TMAA is a polygon roughly resembling a 
rectangle oriented from northwest to southeast, approximately 300 
nautical miles (nmi; 556 km) in length by 150 nmi (278 km) in width, 
located south of Montague Island and east of Kodiak Island. The warning 
area overlaps and extends slightly beyond the northern corner of the 
TMAA. The WMA provides an additional 185,806 nmi\2\ of surface, sub-
surface, and airspace training area to support activities occurring 
within the TMAA. The boundary of the WMA follows the bottom of the 
slope at the 4,000 m contour line.
    (c) The taking of marine mammals by the Navy is only authorized if 
it occurs incidental to the Navy conducting training activities, 
including:
    (1) Anti-Submarine Warfare; and
    (2) Surface Warfare.


Sec.  218.151   Effective dates and definitions.

    (a) Regulations in this subpart are effective February 3, 2023 
through February 2, 2030.

[[Page 691]]

    (b) In additions to the definitions contained in section 2 of the 
Marine Mammal Protection Act (MMPA), 16 U.S.C. 1362, and Sec.  218.103, 
the following definitions apply to this subpart:
    (1) GOA Study Area means the area described in Sec.  218.150(b).
    (2) TMAA means Temporary Maritime Activities Area, as described in 
Sec.  218.150(b).
    (3) WMA means Western Maneuver Area, as described in Sec.  
218.150(b).
    (4) LOA means a Letter of Authorization issued under Sec. Sec.  
216.106 of this chapter and 218.156.
    (5) MTE means major training exercise.
    (6) Navy means United States Department of the Navy.
    (7) Navy personnel means active-duty and reserve uniformed Navy 
personnel and Navy civil servants.
    (8) Navy contractor means any individual, firm, corporation, 
partnership, association, or other legal non-Federal entity that enters 
into a contract directly with the Navy to furnish services, supplies, 
or construction and is performing or acting in furtherance of those 
duties.
    (9) Lookout means an individual designated the responsibility of 
visually observing mitigation zones.
    (10) Training activities means military readiness activities 
described in Sec.  218.150.


Sec.  218.152   Permissible methods of taking.

    (a) Under an LOA issued pursuant to Sec. Sec.  216.106 of this 
chapter and 218.156, the Navy may incidentally, but not intentionally, 
take marine mammals within the TMAA only, by Level A harassment and 
Level B harassment associated with the use of active sonar and other 
acoustic sources and explosives, provided the activity is in compliance 
with all terms, conditions, and requirements of this subpart and the 
applicable LOA.
    (b) The incidental take of marine mammals by the activities listed 
in Sec.  218.150(c) is limited to the following species:

                      Table 1 to Sec.   218.152(b)
------------------------------------------------------------------------
           Species                               Stock
------------------------------------------------------------------------
Blue whale...................  Central North Pacific.
Blue whale...................  Eastern North Pacific.
Fin whale....................  Northeast Pacific.
Humpback whale...............  Western North Pacific.
Humpback whale...............  Central North Pacific.
Humpback whale...............  California/Oregon/Washington.
Minke whale..................  Alaska.
North Pacific right whale....  Eastern North Pacific.
Sei whale....................  Eastern North Pacific.
Gray whale...................  Eastern North Pacific.
Killer whale.................  Eastern North Pacific Offshore.
Killer whale.................  Eastern North Pacific Gulf of Alaska,
                                Aleutian Islands, and Bering Sea
                                Transient.
Pacific white-sided dolphin..  North Pacific.
Dall's porpoise..............  Alaska.
Sperm whale..................  North Pacific.
Baird's beaked whale.........  Alaska.
Cuvier's beaked whale........  Alaska.
Stejneger's beaked whale.....  Alaska.
Northern fur seal............  Eastern Pacific.
Northern fur seal............  California.
Northern elephant seal.......  California.
------------------------------------------------------------------------

Sec.  218.153  Prohibitions.

    (a) Except for incidental takings contemplated in Sec.  218.152(a) 
and authorized by an LOA issued under Sec. Sec.  216.106 of this 
chapter and 218.156, it shall be unlawful for any person to do any of 
the following in connection with the activities listed in Sec.  
218.150(c):
    (1) Violate, or fail to comply with, the terms, conditions, and 
requirements of this subpart or an LOA issued under Sec. Sec.  216.106 
of this chapter and 218.156;
    (2) Take any marine mammal not specified in Sec.  218.152(b);
    (3) Take any marine mammal specified in Sec.  218.152(b) in any 
manner other than as specified in the LOA; or
    (4) Take a marine mammal specified in Sec.  218.152(b) if the 
National Marine Fisheries Service (NMFS) determines such taking results 
in more than a negligible impact on the species or stocks of such 
marine mammal.
    (b) [Reserved]


Sec.  218.154   Mitigation requirements.

    (a) When conducting the activities identified in Sec.  218.150(c), 
the mitigation measures contained in any LOA issued under Sec. Sec.  
216.106 of this chapter and 218.156 must be implemented. If Navy 
contractors are serving in a role similar to Navy personnel, Navy 
contractors will follow the mitigation applicable to Navy personnel. 
These mitigation measures include, but are not limited to:
    (1) Procedural mitigation. Procedural mitigation is mitigation that 
the Navy must implement whenever and wherever an applicable training 
activity takes place within the GOA Study Area for acoustic stressors 
(i.e., active sonar, weapons firing noise), explosive stressors (i.e., 
large-caliber projectiles, bombs), 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 bombs).
    (i) Environmental awareness and education. Appropriate Navy 
personnel (including civilian personnel) involved in mitigation and 
training activity reporting under the specified activities must 
complete the environmental compliance training modules identified in 
their career path training plan, as specified in the LOA.
    (ii) Active sonar. Active sonar includes mid-frequency active sonar 
and high-frequency active sonar. For vessel-based active sonar 
activities, mitigation applies only to sources that are positively 
controlled and deployed from manned surface vessels (e.g., sonar 
sources towed from manned surface platforms). For aircraft-based active 
sonar activities, mitigation applies only to sources that are 
positively controlled and deployed from manned aircraft that do not 
operate at high altitudes (e.g.,

[[Page 692]]

rotary-wing aircraft). Mitigation does not apply to active sonar 
sources deployed from unmanned aircraft or aircraft operating at high 
altitudes (e.g., maritime patrol aircraft).
    (A) Number of Lookouts and observation platform for hull-mounted 
sources. For hull-mounted sources, the Navy must have one Lookout for 
platforms with space or manning restrictions while underway (at the 
forward part of a small boat or ship) and platforms using active sonar 
while moored or at anchor; and two Lookouts for platforms without space 
or manning restrictions while underway (at the forward part of the 
ship).
    (B) Number of Lookouts and observation platform for sources not 
hull-mounted. For sources that are not hull-mounted, the Navy must have 
one Lookout on the ship or aircraft conducting the activity.
    (C) Prior to activity. Prior to the initial start of the activity 
(e.g., when maneuvering on station), Navy personnel must observe the 
mitigation zone for floating vegetation and marine mammals; if floating 
vegetation or a marine mammal is observed, Navy personnel must relocate 
or delay the start of active sonar transmission until the mitigation 
zone is clear of floating vegetation or until the conditions in 
paragraph (a)(1)(ii)(F) of this section are met for marine mammals.
    (D) During the activity for hull-mounted mid-frequency active 
sonar. During the activity, for hull-mounted mid-frequency active 
sonar, Navy personnel must observe the following mitigation zones for 
marine mammals.
    (1) Powerdowns for marine mammals. Navy personnel must power down 
active sonar transmission by 6 dB if a marine mammal is observed within 
1,000 yd (914.4 m) of the sonar source; Navy personnel must power down 
active sonar transmission an additional 4 dB (10 dB total) if a marine 
mammal is observed within 500 yd (457.2 m) of the sonar source.
    (2) Shutdowns for marine mammals. Navy personnel must cease 
transmission if a marine mammal is observed within 200 yd (182.9 m) of 
the sonar source.
    (E) During the activity, for mid-frequency active sonar sources 
that are not hull-mounted, and high-frequency active sonar. During the 
activity, for mid-frequency active sonar (MFAS) sources that are not 
hull-mounted and high-frequency active sonar (HFAS), Navy personnel 
must observe the mitigation zone for marine mammals. Navy personnel 
must cease transmission if a marine mammal is observed within 200 yd 
(182.9 m) of the sonar source.
    (F) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone 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) until 
one of the following conditions has been met:
    (1) Observed exiting. The animal is observed exiting the mitigation 
zone;
    (2) Thought to have exited. The animal is thought to have exited 
the mitigation zone based on a determination of its course, speed, and 
movement relative to the sonar source;
    (3) Clear from additional sightings. The mitigation zone has been 
clear from any additional sightings for 10 minutes (min) for aircraft-
deployed sonar sources or 30 minutes for vessel-deployed sonar sources;
    (4) Sonar source transit. For mobile activities, the active sonar 
source has transited a distance equal to double that of the mitigation 
zone size beyond the location of the last sighting; or
    (5) Bow-riding dolphins. For activities using hull-mounted sonar, 
the Lookout concludes that dolphins are deliberately closing in on the 
ship to ride the ship's bow wave, and are therefore out of the main 
transmission axis of the sonar (and there are no other marine mammal 
sightings within the mitigation zone).
    (iii) Weapons firing noise. Weapons firing noise associated with 
large-caliber gunnery activities.
    (A) Number of Lookouts and observation platform. One Lookout must 
be positioned on the ship conducting the firing. Depending on the 
activity, the Lookout could be the same as the one provided for in 
paragraphs (a)(1)(iv)(A) and (a)(1)(viii)(A) of this section.
    (B) Mitigation zone. Thirty degrees on either side of the firing 
line out to 70 yd (64 m) from the muzzle of the weapon being fired.
    (C) Prior to activity. Prior to the initial start of the activity, 
Navy personnel must observe the mitigation zone for floating vegetation 
and marine mammals; if floating vegetation or a marine mammal is 
observed, Navy personnel must relocate or delay the start of weapons 
firing until the mitigation zone is clear of floating vegetation or 
until the conditions in paragraph (a)(1)(iii)(E) of this section are 
met for marine mammals.
    (D) During activity. During the activity, Navy personnel must 
observe the mitigation zone for marine mammals; if a marine mammal is 
observed, Navy personnel must cease weapons firing.
    (E) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing weapons firing) until one of the following 
conditions has been met:
    (1) Observed exiting. The animal is observed exiting the mitigation 
zone;
    (2) Thought to have exited. The animal is thought to have exited 
the mitigation zone based on a determination of its course, speed, and 
movement relative to the firing ship;
    (3) Clear from additional sightings. The mitigation zone has been 
clear from any additional sightings for 30 min; or
    (4) Firing ship transit. For mobile activities, the firing ship has 
transited a distance equal to double that of the mitigation zone size 
beyond the location of the last sighting.
    (iv) Explosive large-caliber projectiles. Gunnery activities using 
explosive large-caliber projectiles. Mitigation applies to activities 
using a surface target.
    (A) Number of Lookouts and observation platform. One Lookout must 
be on the vessel or aircraft conducting the activity. Depending on the 
activity, the Lookout could be the same as the one described in 
paragraph (a)(1)(iii)(A) of this section. If additional platforms are 
participating in the activity, Navy personnel positioned in those 
assets (e.g., safety observers, evaluators) must support observing the 
mitigation zone for marine mammals while performing their regular 
duties.
    (B) Mitigation zones. 1,000 yd (914.4 m) around the intended impact 
location.
    (C) Prior to activity. Prior to the initial start of the activity 
(e.g., when maneuvering on station), Navy personnel must observe the 
mitigation zone for floating vegetation and marine mammals; if floating 
vegetation or a marine mammal is observed, Navy personnel must relocate 
or delay the start of firing until the mitigation zone is clear of 
floating vegetation or until the conditions in paragraph (a)(1)(iv)(E) 
of this section are met for marine mammals.
    (D) During activity. During the activity, Navy personnel must 
observe the mitigation zone for marine mammals; if a marine mammal is 
observed, Navy personnel must cease firing.
    (E) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation

[[Page 693]]

zone prior to the initial start of the activity (by delaying the start) 
or during the activity (by not recommencing firing) until one of the 
following conditions has been met:
    (1) Observed exiting. The animal is observed exiting the mitigation 
zone;
    (2) Thought to have exited. The animal is thought to have exited 
the mitigation zone based on a determination of its course, speed, and 
movement relative to the intended impact location;
    (3) Clear of additional sightings. The mitigation zone has been 
clear from any additional sightings for 30 minutes; or,
    (4) Impact location transit. For activities using mobile targets, 
the intended impact location has transited a distance equal to double 
that of the mitigation zone size beyond the location of the last 
sighting.
    (F) After activity. After completion of the activity (e.g., prior 
to maneuvering off station), Navy personnel must, when practical (e.g., 
when platforms are not constrained by fuel restrictions or mission-
essential follow-on commitments), observe for marine mammals in the 
vicinity of where detonations occurred; if any injured or dead marine 
mammals are observed, Navy personnel must follow established incident 
reporting procedures. If additional platforms are supporting this 
activity (e.g., providing range clearance), Navy personnel positioned 
on these Navy assets must assist in the visual observation of the area 
where detonations occurred.
    (v) Explosive bombs--(A) Number of Lookouts and observation 
platform. One Lookout must be positioned in an aircraft conducting the 
activity. If additional platforms are participating in the activity, 
Navy personnel positioned in those assets (e.g., safety observers, 
evaluators) must support observing the mitigation zone for marine 
mammals while performing their regular duties.
    (B) Mitigation zone. 2,500 yd (2,286 m) around the intended target.
    (C) Prior to activity. Prior to the initial start of the activity 
(e.g., when arriving on station), Navy personnel must observe the 
mitigation zone for floating vegetation and marine mammals; if floating 
vegetation or a marine mammal is observed, Navy personnel must relocate 
or delay the start of bomb deployment until the mitigation zone is 
clear of floating vegetation or until the conditions in paragraph 
(a)(1)(v)(E) of this section are met for marine mammals.
    (D) During activity. During the activity (e.g., during target 
approach), Navy personnel must observe the mitigation zone for marine 
mammals; if a marine mammal is observed, Navy personnel must cease bomb 
deployment.
    (E) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing bomb deployment) until one of the following 
conditions has been met:
    (1) Observed exiting. The animal is observed exiting the mitigation 
zone;
    (2) Thought to have exited. The animal is thought to have exited 
the mitigation zone based on a determination of its course, speed, and 
movement relative to the intended target;
    (3) Clear from additional sightings. The mitigation zone has been 
clear from any additional sightings for 10 min; or
    (4) Intended target transit. For activities using mobile targets, 
the intended target has transited a distance equal to double that of 
the mitigation zone size beyond the location of the last sighting.
    (F) After activity. After completion of the activity (e.g., prior 
to maneuvering off station), Navy personnel must, when practical (e.g., 
when platforms are not constrained by fuel restrictions or mission-
essential follow-on commitments), observe for marine mammals in the 
vicinity of where detonations occurred; if any injured or dead marine 
mammals are observed, Navy personnel must follow established incident 
reporting procedures. If additional platforms are supporting this 
activity (e.g., providing range clearance), Navy personnel positioned 
on these Navy assets must assist in the visual observation of the area 
where detonations occurred.
    (vi) Vessel movement. The mitigation will not be applied if: the 
vessel's safety is threatened; the vessel is restricted in its ability 
to maneuver (e.g., during launching and recovery of aircraft or landing 
craft, during towing activities, when mooring); the vessel is submerged 
or operated autonomously; or when impractical based on mission 
requirements (e.g., during Vessel Visit, Board, Search, and Seizure 
activities as military personnel from ships or aircraft board suspect 
vessels).
    (A) Number of Lookouts and observation platform. One or more 
Lookouts must be on the underway vessel. If additional watch personnel 
are positioned on the underway vessel, those personnel (e.g., persons 
assisting with navigation or safety) must support observing for marine 
mammals while performing their regular duties.
    (B) Mitigation zone--(1) Whales. 500 yd (457.2 m) around the vessel 
for whales.
    (2) Marine mammals other than whales. 200 yd (182.9 m) around the 
vessel for all marine mammals other than whales (except those 
intentionally swimming alongside or closing in to swim alongside 
vessels, such as bow-riding or wake-riding dolphins).
    (C) When underway. Navy personnel must observe the direct path of 
the vessel and waters surrounding the vessel for marine mammals. If a 
marine mammal is observed in the direct path of the vessel, Navy 
personnel must maneuver the vessel as necessary to maintain the 
appropriate mitigation zone distance. If a marine mammal is observed 
within waters surrounding the vessel, Navy personnel must maintain 
situational awareness of that animal's position. Based on the animal's 
course and speed relative to the vessel's path, Navy personnel must 
maneuver the vessel as necessary to ensure that the appropriate 
mitigation zone distance from the animal continues to be maintained.
    (D) Incident reporting procedures. If a marine mammal vessel strike 
occurs, Navy personnel must follow the established incident reporting 
procedures.
    (vii) Towed in-water devices. Mitigation applies to devices that 
are towed from a manned surface platform or manned aircraft, or when a 
manned support craft is already participating in an activity involving 
in-water devices being towed by unmanned platforms. The mitigation will 
not be applied if the safety of the towing platform or in-water device 
is threatened.
    (A) Number of Lookouts and observation platform. One Lookout must 
be positioned on a manned towing platform or support craft.
    (B) Mitigation zone. 250 yd (228.6 m) around the towed in-water 
device for marine mammals (except those intentionally swimming 
alongside or choosing to swim alongside towing vessels, such as bow-
riding or wake-riding dolphins).
    (C) During activity. During the activity (i.e., when towing an in-
water device), Navy personnel must observe the mitigation zone for 
marine mammals; if a marine mammal is observed, Navy personnel must 
maneuver to maintain distance.
    (viii) Small-, medium-, and large-caliber non-explosive practice 
munitions. Gunnery activities using small-, medium-, and large-caliber 
non-explosive practice munitions. Mitigation applies to activities 
using a surface target.

[[Page 694]]

    (A) Number of Lookouts and observation platform. One Lookout must 
be positioned on the platform conducting the activity. Depending on the 
activity, the Lookout could be the same as the one described in 
paragraph (a)(1)(iii)(A) of this section.
    (B) Mitigation zone. 200 yd (182.9 m) around the intended impact 
location.
    (C) Prior to activity. Prior to the initial start of the activity 
(e.g., when maneuvering on station), Navy personnel must observe the 
mitigation zone for floating vegetation and marine mammals; if floating 
vegetation or a marine mammal is observed, Navy personnel must relocate 
or delay the start of firing until the mitigation zone is clear of 
floating vegetation or until the conditions in paragraph 
(a)(1)(viii)(E) of this section are met for marine mammals.
    (D) During activity. During the activity, Navy personnel must 
observe the mitigation zone for marine mammals; if a marine mammal is 
observed, Navy personnel must cease firing.
    (E) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing firing) until one of the following conditions has 
been met:
    (1) Observed exiting. The animal is observed exiting the mitigation 
zone;
    (2) Thought to have exited. The animal is thought to have exited 
the mitigation zone based on a determination of its course, speed, and 
movement relative to the intended impact location;
    (3) Clear of additional sightings. The mitigation zone has been 
clear from any additional sightings for 10 minutes for aircraft-based 
firing or 30 minutes for vessel-based firing; or
    (4) Impact location transit. For activities using a mobile target, 
the intended impact location has transited a distance equal to double 
that of the mitigation zone size beyond the location of the last 
sighting.
    (ix) Non-explosive bombs--(A) Number of Lookouts and observation 
platform. One Lookout must be positioned in an aircraft.
    (B) Mitigation zone. 1,000 yd (914.4 m) around the intended target.
    (C) Prior to activity. Prior to the initial start of the activity 
(e.g., when arriving on station), Navy personnel must observe the 
mitigation zone for floating vegetation and marine mammals; if floating 
vegetation or a marine mammal is observed, Navy personnel must relocate 
or delay the start of bomb deployment until the mitigation zone is 
clear of floating vegetation or until the conditions in paragraph 
(a)(1)(ix)(E) of this section are met for marine mammals.
    (D) During activity. During the activity (e.g., during approach of 
the target), Navy personnel must observe the mitigation zone for marine 
mammals and, if a marine mammal is observed, Navy personnel must cease 
bomb deployment.
    (E) Commencement/recommencement conditions after a marine mammal 
sighting prior to or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing bomb deployment) until one of the following 
conditions has been met:
    (1) Observed exiting. The animal is observed exiting the mitigation 
zone;
    (2) Thought to have exited. The animal is thought to have exited 
the mitigation zone based on a determination of its course, speed, and 
movement relative to the intended target;
    (3) Clear from additional sightings. The mitigation zone has been 
clear from any additional sightings for 10 min; or
    (4) Intended target transit. For activities using mobile targets, 
the intended target has transited a distance equal to double that of 
the mitigation zone size beyond the location of the last sighting.
    (2) Mitigation areas. In addition to procedural mitigation, Navy 
personnel must implement mitigation measures within mitigation areas to 
avoid or reduce potential impacts on marine mammals.
    (i) North Pacific Right Whale Mitigation Area. Figure 1 to this 
paragraph (a)(2) shows the location of the mitigation area.
    (A) Surface ship hull-mounted MF1 mid-frequency active sonar. From 
June 1-September 30 within the North Pacific Right Whale Mitigation 
Area, Navy personnel must not use surface ship hull-mounted MF1 mid-
frequency active sonar during training.
    (B) National security exception. Should national security require 
that the Navy cannot comply with the restrictions in paragraph 
(a)(2)(i)(A) of this section, Navy personnel must obtain permission 
from the designated Command, U.S. Third Fleet Command Authority, prior 
to commencement of the activity. Navy personnel must provide NMFS with 
advance notification and include information about the event in its 
annual activity reports to NMFS.
    (ii) Continental Shelf and Slope Mitigation Area. Figure 1 to this 
paragraph (a)(2) shows the location of the mitigation area.
    (A) Explosives. During training, Navy personnel must not detonate 
explosives below 10,000 ft. altitude (including at the water surface) 
in the Continental Shelf and Slope Mitigation Area, which extends over 
the continental shelf and slope out to the 4,000 m depth contour within 
the TMAA.
    (B) National security exception. Should national security require 
that the Navy cannot comply with the restrictions in paragraph 
(a)(2)(ii)(A) of this section, Navy personnel must obtain permission 
from the designated Command, U.S. Third Fleet Command Authority, prior 
to commencement of the activity. Navy personnel must provide NMFS with 
advance notification and include information about the event in its 
annual activity reports to NMFS.
    (iii) Pre-event awareness notifications in the Temporary Maritime 
Activities Area. The Navy must issue pre-event awareness messages to 
alert vessels and aircraft participating in training activities within 
the TMAA to the possible presence of concentrations of large whales on 
the continental shelf and slope. Occurrences of large whales may be 
higher over the continental shelf and slope relative to other areas of 
the TMAA. Large whale species in the TMAA include, but are not limited 
to, fin whale, blue whale, humpback whale, gray whale, North Pacific 
right whale, sei whale, and sperm whale. To maintain safety of 
navigation and to avoid interactions with marine mammals, the Navy must 
instruct personnel to remain vigilant to the presence of large whales 
that may be vulnerable to vessel strikes or potential impacts from 
training activities. Additionally, Navy personnel must use the 
information from the awareness notification messages to assist their 
visual observation of applicable mitigation zones during training 
activities and to aid in the implementation of procedural mitigation.

Figure 1 to Paragraph (a)(2)--Geographic Mitigation Areas for Marine 
Mammals in the GOA Study Area

BILLING CODE 3510-22-P

[[Page 695]]

[GRAPHIC] [TIFF OMITTED] TR04JA23.109

BILLING CODE 3510-22-C
    (b) [Reserved]


Sec.  218.155  Requirements for monitoring and reporting.

    (a) Unauthorized take. Navy personnel must notify NMFS immediately 
(or as soon as operational security considerations allow) if the 
specified activity identified in Sec.  218.150 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 
authorized under this subpart.
    (b) Monitoring and reporting under the LOA. The Navy must conduct 
all monitoring and reporting required under the LOA, including abiding 
by the U.S. Navy's Marine Species Monitoring Program. Details on 
program goals, objectives, project selection process, and current 
projects are available at www.navymarinespeciesmonitoring.us.
    (c) Notification of injured, live stranded, or dead marine mammals. 
Navy personnel must consult 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.

[[Page 696]]

    (d) Annual GOA Marine Species Monitoring Report. The Navy must 
submit an annual report of the GOA Study Area monitoring, which will be 
included in a Pacific-wide monitoring report and include results 
specific to the GOA Study Area, describing the implementation and 
results from the previous calendar year. Data collection methods must 
be standardized across Pacific Range Complexes including the Mariana 
Islands Training and Testing (MITT), Hawaii-Southern California 
Training and Testing (HSTT), Northwest Training and Testing (NWTT), and 
Gulf of Alaska (GOA) Study Areas to allow for comparison among 
different geographic locations. The report must be submitted to the 
Director, Office of Protected Resources, NMFS, either within 3 months 
after the end of the calendar year, or within 3 months after the 
conclusion of the monitoring year, to be determined by the adaptive 
management process. NMFS will submit comments or questions on the 
report, if any, within 3 months of receipt. The report will be 
considered final after the Navy has addressed NMFS' comments, or 3 
months after submittal if NMFS does not provide comments on the report. 
This report will describe progress of knowledge made with respect to 
intermediate scientific objectives within the GOA Study Area associated 
with the Integrated Comprehensive Monitoring Program. 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 does not provide direct assessment of 
cumulative progress on the monitoring plan study questions. This will 
continue to allow the Navy to provide a cohesive monitoring report 
covering multiple ranges (as per Integrated Comprehensive Monitoring 
Program goals), rather than entirely separate reports for the GOA, 
NWTT, HSTT, and MITT Study Areas.
    (e) GOA Annual Training Report. Each year in which training 
activities are conducted in the GOA Study Area, the Navy must submit 
one preliminary report (Quick Look Report) to NMFS detailing the status 
of applicable sound sources within 21 days after the completion of the 
training activities in the GOA Study Area. Each year in which 
activities are conducted, the Navy must also submit a detailed report 
(GOA Annual Training Report) to the Director, Office of Protected 
Resources, NMFS, within 3 months after completion of the training 
activities. NMFS must submit comments or questions on the report, if 
any, within one month of receipt. The report will be considered final 
after the Navy has addressed NMFS' comments, or one month after 
submittal if NMFS does not provide comments on the report. The annual 
reports must contain information about the major training exercise 
(MTE), including the information listed in paragraphs (e)(1) and (2) of 
this section. The annual report, which is only required during years in 
which activities are conducted, 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 report must 
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 GOA 
Final Supplemental Environmental Impact Statement/Overseas 
Environmental Impact Statement (FSEIS/OEIS) (https://www.goaeis.com/) 
and MMPA final rule (87 FR [INSERT FR PAGE NUMBER], [January 4, 2023). 
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 seven) will also serve as the 
comprehensive close-out report and include both the final year annual 
use compared to annual authorization as well as a cumulative 7-year 
annual use compared to 7-year authorization. This report must also note 
any years in which training did not occur. NMFS must submit comments on 
the draft close-out report, if any, within 3 months of receipt. The 
report will be considered final after the Navy has addressed NMFS' 
comments, or 3 months after the submittal if NMFS does not provide 
comments. Information included in the annual reports may be used to 
inform future adaptive management of activities within the GOA Study 
Area. In addition to the information discussed above, the GOA Annual 
Training Report must include the following information.
    (1) MFAS/HFAS. The Navy must submit the following information for 
the MTE conducted in the GOA Study Area.
    (i) Exercise information (for each MTE). (A) Exercise designator.
    (B) Date that exercise began and ended.
    (C) Location.
    (D) Number and types of active sources used in the exercise.
    (E) Number and types of passive acoustic sources used in exercise.
    (F) Number and types of vessels, aircraft, etc., participating in 
exercise.
    (G) Total hours of observation by Lookouts.
    (H) Total hours of all active sonar source operation.
    (I) Total hours of each active sonar source bin.
    (J) Wave height (high, low, and average during exercise).
    (ii) Individual marine mammal sighting information for each 
sighting in each exercise where mitigation was implemented. (A) Date/
time/location of sighting.
    (B) Species (if not possible, indication of whale/dolphin/
pinniped).
    (C) Number of individuals.
    (D) Initial detection sensor (e.g., sonar or Lookout).
    (E) Indication of specific type of platform observation 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 to 914.4 m), 
1,000 to 2,000 yd (914.4 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 how long the delay was.
    (L) If source in use is hull-mounted, true bearing of animal from 
ship, true direction of ship's travel, and estimation of animal's 
motion relative to ship (opening, closing, parallel).
    (M) Lookouts shall report, in plain language and without trying to 
categorize in any way, the observed behavior of the animals (such as 
animal closing to bow ride, paralleling course/speed, floating on 
surface and not swimming, etc.) and if any calves 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. This evaluation 
shall identify the specific observations that support any conclusions 
the Navy reaches about the effectiveness of the mitigation.
    (2) Summary of sources used. (i) This section shall include the 
following information summarized from the authorized sound sources used 
in all training events:
    (A) Total hours. Total annual hours or quantity (per the LOA) of 
each bin of sonar or other non-impulsive source; and

[[Page 697]]

    (B) Number of explosives. Total annual number of each type of 
explosive exercises and total annual expended/detonated rounds (bombs, 
large-caliber projectiles) for each explosive bin.
    (f) Pre-event notification. The Navy must coordinate with NMFS 
prior to conducting exercises within the GOA Study Area. This may occur 
as a part of coordination the Navy does with other local stakeholders.


Sec.  218.156  Letters of Authorization.

    (a) To incidentally take marine mammals pursuant to this subpart, 
the Navy must apply for and obtain an LOA in accordance with Sec.  
216.106 of this chapter.
    (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) If an LOA expires prior to the expiration date of this subpart, 
the Navy may apply for and obtain a renewal of the LOA.
    (d) In the event of projected changes to the activity or to 
mitigation, monitoring, or reporting (excluding changes made pursuant 
to the adaptive management provision of Sec.  218.157(c)(1)) required 
by an LOA issued under this subpart, the Navy must apply for and obtain 
a modification of the LOA as described in Sec.  218.157.
    (e) 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.
    (f) Issuance of the LOA will be based on a determination that the 
level of taking is consistent with the findings made for the total 
taking allowable under this subpart.
    (g) Notice of issuance or denial of the LOA will be published in 
the Federal Register within 30 days of a determination.


Sec.  218.157   Renewals and modifications of Letters of Authorization.

    (a) An LOA issued under Sec. Sec.  216.106 of this chapter and 
218.156 for the activity identified in Sec.  218.150(c) may be renewed 
or modified upon request by the applicant, provided that:
    (1) The planned specified activity and mitigation, monitoring, and 
reporting measures, as well as the anticipated impacts, are the same as 
those described and analyzed for 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 LOA were implemented.
    (b) For LOA modification or renewal requests by the applicant 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) that do not 
change the findings made for this subpart or result in no more than a 
minor change in the total estimated number of takes (or distribution by 
species or stock or years), NMFS may publish a notice of the proposed 
changes to the 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 of this chapter and 
218.156 may be modified by NMFS under the following circumstances:
    (1) After consulting with the Navy regarding the practicability of 
the modifications, NMFS may modify (including adding or removing 
measures) 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.
    (i) Possible sources of data that could contribute to the decision 
to modify the mitigation, monitoring, or reporting measures in an LOA 
include:
    (A) Results from the Navy's monitoring 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 a 
subsequent LOA.
    (ii) If, through adaptive management, the modifications to the 
mitigation, monitoring, or reporting measures are more than minor, NMFS 
will publish a notice of the proposed changes to the LOA in the Federal 
Register and solicit public comment.
    (2) If NMFS 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 218.156, an 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.  218.158  [Reserved]

[FR Doc. 2022-27951 Filed 1-3-23; 8:45 am]
BILLING CODE 3510-22-P