[Federal Register Volume 84, Number 41 (Friday, March 1, 2019)]
[Proposed Rules]
[Pages 7186-7259]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-03298]
[[Page 7185]]
Vol. 84
Friday,
No. 41
March 1, 2019
Part II
Department of Commerce
-----------------------------------------------------------------------
National Oceanic and Atmospheric Administration
-----------------------------------------------------------------------
50 CFR Part 218
Takes of Marine Mammals Incidental to Specified Activities: Taking
Marine Mammals Incidental to U.S. Navy Surveillance Towed Array Sensor
System Low Frequency Active Sonar Training and Testing in the Central
and Western North Pacific Ocean and Eastern Indian Ocean; Proposed Rule
Federal Register / Vol. 84 , No. 41 / Friday, March 1, 2019 /
Proposed Rules
[[Page 7186]]
-----------------------------------------------------------------------
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 218
[Docket No. 180809740-9103-01]
RIN 0648-BI42
Takes of Marine Mammals Incidental to Specified Activities:
Taking Marine Mammals Incidental to U.S. Navy Surveillance Towed Array
Sensor System Low Frequency Active Sonar Training and Testing in the
Central and Western North Pacific Ocean and Eastern Indian Ocean
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Proposed rule; request for comments.
-----------------------------------------------------------------------
SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for
authorization to take marine mammals incidental to the use of
Surveillance Towed Array Sensor System Low Frequency Active (SURTASS
LFA) sonar systems onboard U.S. Navy surveillance ships for training
and testing activities conducted under the authority of the Secretary
of the Navy in the western and central North Pacific Ocean and eastern
Indian Ocean (SURTASS LFA sonar activities) beginning August 2019.
Pursuant to section 101(a)(5)(A) of the MMPA, NMFS is requesting
comments on its proposal to issue regulations to govern the incidental
take of marine mammals by Level B harassment during SURTASS LFA sonar
activities. The Fiscal Year 2019 (FY19) National Defense Authorization
Act (NDAA), signed on August 13, 2018, amended the Marine Mammal
Protection Act to extend the maximum authorization period of permitted
incidental takings of marine mammals under section 101(a)(5)(A) in the
course of specified military readiness activities by the Department of
Defense from five to seven years. Therefore, the authorization, if
issued, would be in effect from August 2019 to August 2026. NMFS will
consider public comments prior to making any final decision on the
issuance of the requested MMPA authorization and agency responses will
be summarized in the final notice of our decision. The Navy's
activities are considered military readiness activities pursuant to the
Marine Mammal Protection Act (MMPA), as amended by the National Defense
Authorization Act for Fiscal Year 2004 (FY 2004 NDAA).
DATES: Comments and information must be received no later than April 1,
2019.
ADDRESSES: You may submit comments on this document, identified by
NOAA-NMFS-2019-0014, by any of the following methods:
Electronic submission: Submit all electronic public
comments via the Federal e-Rulemaking Portal. Go to
www.regulations.gov/#!docketDetail;D =NOAA-NMFS-2019-0014, click the
``Comment Now!'' icon, complete the required fields, and enter or
attach your comments.
Mail: Submit written comments to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service, 1315 East-West Highway, Silver
Spring, MD 20910.
Instructions: Comments sent by any other method, to any other
address or individual, or received after the end of the comment period,
may not be considered by NMFS. All comments received are a part of the
public record and will generally be posted for public viewing on
www.regulations.gov without change. All personal identifying
information (e.g., name, address), confidential business information,
or otherwise sensitive information submitted voluntarily by the sender
will be publicly accessible. NMFS will accept anonymous comments (enter
``N/A'' in the required fields if you wish to remain anonymous).
Attachments to electronic comments will be accepted in Microsoft Word,
Excel, or Adobe PDF file formats only.
FOR FURTHER INFORMATION CONTACT: Wendy Piniak, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Availability
A copy of the Navy's application and any supporting documents, as
well as a list of the references cited in this document, may be
obtained online at: https://www.fisheries.noaa.gov/national/marine-
mammal-protection/incidental-take-authorizations-military-readiness-
activities. In case of problems accessing these documents, please call
the contact listed above (see FOR FURTHER INFORMATION CONTACT).
Purpose and Need for Regulatory Action
NMFS received an application from the Navy requesting regulations
and a related letter or letters of authorization (LOA) to take multiple
species of marine mammals by Level B harassment incidental to SURTASS
LFA sonar activities. Please see ``Background'' below for definitions
of harassment. This proposed rule would establish a framework under the
authority of the MMPA (16 U.S.C. 1361 et seq.) to allow for the
authorization of take of marine mammals incidental to the Navy's
specified activities.
Legal Authority for the Proposed Action
Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A))
generally directs the Secretary of Commerce 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 for up to
five years if, after notice and public comment, the agency makes
certain findings and issues regulations that set forth permissible
methods of taking and other means of effecting the least practicable
adverse impact on the affected species or stocks and their habitat (see
the discussion below in the Proposed Mitigation section), 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 proposed rule and any associated LOAs.
As described in the next section, the MMPA has been amended in a number
of ways when the specified activity is a military readiness activity,
including most recently in 2018 to extend the maximum authorization
period under section 101(a)(5)(A) to seven years for Department of
Defense military readiness activities. As directed by this legal
authority, this proposed rule contains mitigation, monitoring, and
reporting requirements.
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are issued or, if the taking is limited to harassment, an incidental
harassment authorization may be issued following notice and opportunity
for public comment.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have
[[Page 7187]]
an unmitigable adverse impact on the availability of the species or
stock(s) for taking for subsistence uses (where relevant). Further,
NMFS must prescribe the permissible methods of taking 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 such species or stocks for taking for certain
subsistence uses (referred to in shorthand as ``mitigation''), and
requirements pertaining to the monitoring and reporting of such
takings.
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 it applies to a ``military
readiness activity'' to read as follows (Section 3(18)(B) of the MMPA):
(i) Any act that injures or has the significant potential to injure a
marine mammal or marine mammal stock in the 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 FY 2004 NDAA amended the MMPA as it
relates to military readiness activities and the incidental take
authorization (ITA) process such that ``least practicable adverse
impact'' shall include consideration of personnel safety, practicality
of implementation, and impact on the effectiveness of the military
readiness activity. As mentioned above, the NDAA for FY 2019 amended
the MMPA to extend the authorized period of permitted incidental
takings of marine mammals covered by section 101(a)(5)(A) in the course
of specified military readiness activities from five to seven years.
The allowance of incidental taking under section 101(a)(5)(A)
requires promulgation of activity-specific regulations. Under NMFS'
implementing regulations for section 101(a)(5)(A), a Letter of
Authorization (LOA) may be issued consistent with the activity-specific
regulations, provided that the level of taking will be consistent with
the findings made for the total taking allowable under the specific
regulations. The promulgation of activity-specific regulations (with
their associated prescribed mitigation, monitoring, and reporting)
requires notice and opportunity for public comment.
National Marine Sanctuaries Act
NMFS will work with NOAA's Office of National Marine Sanctuaries to
fulfill our responsibilities under the NMSA as warranted and will
complete any NMSA requirements prior to a determination on the issuance
of the final rule and LOAs.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must evaluate our proposed action (i.e., the promulgation of
regulations and issuance of the LOA) and alternatives with respect to
potential impacts on the human environment. NMFS is a cooperating
agency on the Navy's supplemental environmental impact statement/
supplemental overseas environmental impact statement (SEIS/SOEIS). NMFS
plans to adopt the Navy's SEIS/SOEIS for SURTASS LFA sonar training and
testing activities, provided our independent evaluation of the document
finds that it includes adequate information analyzing the effects on
the human environment of issuing the incidental take regulations and
LOA.
The Navy published a Notice of Availability of a DSEIS/SOEIS for
employment of SURTASS LFA sonar in the Federal Register on September 7,
2018 (83 FR 45442), which was available for public review and comment
until October 22, 2018. The public may view the DSEIS/SOEIS at: http://www.surtass-lfa-eis.com.
NMFS will evaluate the comments received on the DSEIS/SOEIS and
comments received as a result of this proposed rulemaking prior to
concluding our NEPA process or making a final decision on the request
for incidental take authorization.
Summary of Request
On June 4, 2018, NMFS received a request from the Navy for
authorization to take, by harassment, 46 species of marine mammals
incidental to the use of SURTASS LFA sonar onboard U.S. Navy
surveillance ships for training and testing activities conducted under
the authority of the Secretary of the Navy in the western and central
North Pacific Ocean and eastern Indian Ocean beginning in August 2019.
In light of the FY 2019 NDAA amending section 101(a)(5)(A), the period
for which the regulations would be effective for issuing the LOA under
this rulemaking would extend to August 2026. On July 13, 2018, NMFS
published a notice of receipt (NOR) of the Navy's application in the
Federal Register (83 FR 32615), and requested comments and information
related to the Navy's request. The review and comment period for the
NOR ended on August 13, 2018. We received one comment in response to
the NOR from a private citizen requesting that NMFS deny Navy's
incidental take authorization request to avoid harming or killing
marine mammals. This comment is available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-
take-authorizations-military-readiness-activities. We note that the
Navy has not requested, nor is NMFS anticipating or proposing to
authorize any mortality or any form of Level A harassment and, as
discussed in more detail below, impacts to marine mammals are
anticipated to be limited to Level B harassment only.
The Navy submitted a revised application on November 13, 2018. This
revision included a minor change to the mitigation measures provided in
the June 2018 application that was available for public review during
the review and comment period for the NOR. This revision does not
represent a significant change to the proposed mitigation measures for
this proposed rule; however, the revised application is available here:
https://www.fisheries .noaa.gov/action/incidental-take-authorization-
us-navy-operations-surveillance-towed-array-sensor-system-0 (also see
Proposed Mitigation section of this notice for more detail).
The Navy states, and NMFS concurs, that these SURTASS LFA sonar
activities, classified as military readiness activities, may
incidentally take marine mammals by exposing them to SURTASS LFA sonar
at levels that constitute Level B harassment as defined above. The Navy
requests authorization to take, by Level B Harassment, individuals from
139 stocks of 46 species of marine mammals (10 species of mysticete
(baleen) whales, 31 species of odontocete (toothed) whales, and 5
species of pinnipeds (seals and sea lions)). This rule may also cover
the authorization of take of animals from additional associated stocks
of marine mammals not listed here, should one or more of the stocks
identified in this rule be formally separated into multiple stocks,
provided NMFS is able to confirm the necessary findings for the newly
identified stocks. As discussed later in this document, incidental
takes due to SURTASS LFA sonar will be limited to Level B behavioral
harassment. No takes by
[[Page 7188]]
Level A harassment are proposed to be authorized as Level A harassment
is considered unlikely and will be avoided through the implementation
of the Navy's proposed mitigation measures, as discussed below.
In previous SURTASS LFA sonar rulemakings, NMFS authorized some
Level A harassment takes in an abundance of caution even though Level A
harassment takes were not anticipated. However, to the knowledge of the
Navy and NMFS, no Level A harassment takes have resulted over the 17-
year history of SURTASS LFA sonar activities. Additionally, the
exposure criteria and thresholds for assessing Level A harassment have
been modified since prior rules based on the best available science.
Under these new metrics, the zone for potential injury is substantially
reduced. Therefore, due to the small injury zones and the fact that
mitigation measures would ensure that marine mammals would not be
exposed to received levels associated with injury, the Navy has not
requested authorization for Level A harassment takes, and NMFS is not
proposing to authorize any takes by Level A harassment.
NMFS published the first incidental take rule for SURTASS LFA
sonar, effective from August 2002 through August 2007, on July 16, 2002
(67 FR 46712); the second rule, effective from August 2007 through
August 2012, on August 21, 2007 (72 FR 46846); and the third rule,
effective from August 2012 through August 2017, on August 20, 2012 (77
FR 50290).
In 2016, the Navy submitted an application for a fourth incidental
take regulation under the MMPA (DoN, 2016) for the taking of marine
mammals by harassment incidental to the deployment of up to four
SURTASS LFA sonar systems from August 15, 2017, through August 14,
2022. NMFS published a proposed rule on April 27, 2017 (82 FR 19460).
On August 10, 2017, the Deputy Secretary of Defense, after conferring
with the Secretary of Commerce, determined that it was necessary for
the national defense to exempt all military readiness activities that
use SURTASS LFA sonar from compliance with the requirements of the MMPA
for a period of up to two years beginning August 13, 2017, through
August 12, 2019, or until such time when NMFS issues regulations and an
LOA under MMPA section 101(a)(5)(A) for military readiness activities
associated with the use of SURTASS LFA sonar, whichever is earlier.
During the exemption period, all military readiness activities that
involve the use of SURTASS LFA sonar are required to comply with all
mitigation, monitoring, and reporting measures set forth in the 2017
National Defense Exemption (NDE) for SURTASS LFA sonar, which were
based on the measures included in NMFS' prior (2012) Final Rule (77 FR
50290; August 20, 2012) and 2017 Proposed Rule (82 FR 19460; April 27,
2017). As a result of the NDE (available at http://www.surtass-lfa-eis.com/wp-content/uploads/2018/01/SURTASS_LFA_NDE_10Aug17.pdf), NMFS
did not finalize its April 2017 proposed rule.
The NDE expires August 12, 2019. For this rulemaking, the Navy is
proposing to continue using SURTASS LFA sonar systems onboard United
States Naval Ship (USNS) surveillance ships for training and testing
activities conducted under the authority of the Secretary of the Navy
within the western and central North Pacific Ocean and eastern Indian
Ocean. The operating features of the LFA sonar have remained the same
since the 2001 FOEIS/EIS, except to note that the typical duty cycle of
LFA sonar, based on historical SURTASS LFA sonar use, is 7.5 to 10
percent (DoN, 2007). The maximum duty cycle remained the same at 20
percent.
For this rulemaking, the Navy scoped the geographic extent of the
area where the specified activity will occur (study area) to better
reflect the areas where the Navy anticipates conducting SURTASS LFA
sonar training and testing activities. Whereas the previous
authorizations included certain routine military operations among the
scope of actions analyzed, the Navy also has narrowed the scope of
activities in the current request for authorization to training and
testing activities only due to various statutory and practical
considerations, as described in the SURTASS 2018 DSEIS/OEIS (DoN,
2018), Chapter 1, and discussed further below.
Under the proposed rule, the Navy would transmit a total of up to
496 LFA sonar transmission hours per year for its specified activity,
as described below (see Description of the Specified Activities
section), pooled across all SURTASS LFA sonar-equipped vessels in the
first four years of the authorization, with an increase in usage to a
total of up to 592 LFA transmission hours in years five through seven.
Description of the Specified Activities
Overview
The Navy's primary mission is to organize, train, and equip combat-
ready naval forces capable of accomplishing American strategic
objectives, deterring maritime aggression, and assuring freedom of
navigation in ocean areas. This mission is mandated by Federal law in
Section 5062 of Title 10 of the United States Code, which directs the
Secretary of the Navy to ensure the readiness of the U.S. naval forces.
The Secretary of the Navy and the Chief of Navy Operations (CNO)
have established that anti-submarine warfare (ASW) is a critical
capability for achieving the Navy's mission, and it requires unfettered
access to both the high seas and littoral environments to be prepared
for all potential threats by maintaining ASW core competency. The Navy
is challenged by the increased difficulty in locating undersea threats
solely by using passive acoustic technologies due to the advancement
and use of quieting technologies in diesel-electric and nuclear
submarines. At the same time as the distance at which submarine threats
can be detected decreases due to quieting technologies, improvements in
torpedo and missile design have extended the effective range of these
weapons.
One of the ways the Navy has addressed the changing requirements
for ASW readiness was by developing SURTASS LFA sonar, which is able to
reliably detect quieter and harder-to-find submarines at long range
before these vessels can get within their effective weapons range to
launch against their targets. SURTASS LFA sonar systems have a passive
component (SURTASS), which is a towed line array of hydrophones used to
detect sound emitted or reflected from submerged targets, and an active
component (LFA), which is comprised of a set of acoustic transmitting
elements. The active component detects objects by creating a sound
pulse, or ``ping'' that is transmitted through the water and reflects
off the target, returning in the form of an echo similar to
echolocation used by some marine mammals to locate prey and navigate.
SURTASS LFA sonar systems are long-range sensors that operate in the
low-frequency (LF) band (i.e., 100-500 Hertz (Hz)). Because LF sound
travels in seawater for greater distances than higher frequency sound,
the SURTASS LFA sonar system would meet the need for improved detection
and tracking of new-generation submarines at a longer range and would
maximize the opportunity for U.S. armed forces to safely react to, and
defend against, potential submarine threats while remaining a safe
distance beyond a submarine's effective weapons range. Thus, the active
acoustic component in the SURTASS LFA sonar is an important
augmentation to its passive and tactical systems, as its long-range
detection capabilities can effectively
[[Page 7189]]
counter the threat to the Navy and national security interests posed by
quiet, diesel submarines.
The Navy's proposed specified activity for MMPA incidental take
coverage is the continued employment of SURTASS LFA sonar systems
onboard USNS surveillance ships for training and testing activities
conducted under the authority of the Secretary of the Navy in the
western and central Pacific Ocean and eastern Indian Ocean, which is
classified as a military readiness activity, beginning August 13, 2019.
The use of the SURTASS LFA sonar system would result in acoustic
stimuli from the generation of sound or pressure waves in the water at
or above levels that NMFS has determined would result in take of marine
mammals under the MMPA. This is the principal means of marine mammal
taking associated with these military readiness activities. In addition
to the use of active acoustic sources, the Navy's activities include
the movement of vessels. This document also analyzes the effects of
this aspect of the activities. NMFS does not anticipate takes of marine
mammals to result from ship strikes from any SURTASS LFA vessels
because each vessel moves at a relatively slow speed (10 to 12 knots
(kt) while transiting), especially when towing the SURTASS and LFA
sonar systems (moving at 3 to 4 kt), and for a relatively short period
of time. Combined with the use of mitigation measures as noted below,
it is likely that surveillance vessels would be able to avoid any
marine mammals.
The Navy will restrict SURTASS LFA sonar training and testing
activities to the central and western North Pacific Ocean and eastern
Indian Ocean. The Navy will not conduct training or testing utilizing
SURTASS LFA sonar within the foreign territorial seas of other nations
and will maintain SURTASS LFA sonar received levels below 180 decibels
(dB) re 1 [micro]Pa (root-mean-square (rms)) within 12 nautical miles
(nmi) (22 kilometers (km)) of any emerged land features or within the
boundaries of designated Offshore Biologically Important Areas (OBIAs)
during their effective periods (see Proposed Mitigation section below
for OBIA details). In addition to these geographic mitigation measures,
the Navy will implement procedural mitigation measures including
monitoring for the presence of marine mammals (including visual as well
as active and passive acoustic monitoring) and implementing shutdown
procedures for marine mammals within a mitigation/buffer zone around
the LFA sonar source (see Proposed Mitigation section below for further
details).
Dates and Duration
This proposed rule (if made final) and associated LOA would be
valid beginning August 13, 2019, through August 12, 2026. The Navy
currently conducts SURTASS LFA sonar activities from four vessels. The
Navy is planning to add new vessels to its ocean surveillance fleet. As
new vessels are developed, the onboard LFA and High Frequency Marine
Mammal Monitoring sonar (HF/M3 sonar) systems (discussed below) may
need to be updated, modified, or even re-designed. Current indications
are that future LFA sonar systems will have the same operational
characteristics and that updates and modifications are focused toward
miniaturizing the system components to reduce the weight and handling
of the systems. If system parameters are modified as a result of these
updates the Navy will determine if supplementary analysis would be
required to cover the deployment of these new systems. As the new
vessels and sonar system components are developed and constructed, at-
sea testing would eventually be necessary. The Navy anticipates that
new vessels, or new/updated sonar system components, would be ready for
at-sea testing beginning in the fifth year of the time period covered
by this proposed rule. Thus, the Navy's activity analysis included
consideration of the sonar hours associated with future testing of new
or updated LFA sonar system components and new ocean surveillance
vessels. This consideration resulted in two scenarios of annual sonar
transmit hours: Years 1 to 4 would entail 496 hours total per year
across all SURTASS LFA sonar vessels, while years 5 to 7 would include
an increase in LFA sonar transmit hours to 592 hours across all
vessels.
The SURTASS LFA sonar transmission hours represent a distribution
across six activities that include (with an approximate allocation of
hours indicated):
Contractor crew proficiency training (80 hours per year);
Military crew (MILCREW) proficiency training (96 hours per
year);
Participation in or support of naval exercises (96 hours
per year);
Vessel and equipment maintenance (64 hours per year);
Acoustic research testing (160 hours per year); and
New SURTASS LFA sonar system testing (96 hours per year;
would occur in years 5 to 7).
Each of these activities utilizes the SURTASS LFA sonar system within
the operating profile described above; therefore, the number of hours
designated for each activity is merely an estimate for planning
purposes.
As noted above, this rulemaking would result in the fourth such
regulation for the Navy's SURTASS LFA sonar activities. The Navy is
currently conducting the specified activities under an NDE that will
expire after August 12, 2019. Therefore, the Navy has requested MMPA
rulemaking and a LOA for its SURTASS LFA sonar activities effective
beginning August 13, 2019, to take marine mammals incidental to the
SURTASS LFA sonar activities for a seven year period.
Potential SURTASS LFA Sonar Training and Testing Areas
The potential geographic scope of the SURTASS LFA sonar activities
covered by this proposed rule are the western and central North Pacific
Ocean and eastern Indian Ocean outside of the territorial seas of
foreign nations (generally 12 nautical miles (nmi) (22 kilometers (km)
from most foreign nations). Figure 1 depicts the potential areas of
SURTASS LFA sonar activities. In areas within 12 nmi from any emergent
land (coastal exclusion areas) and in areas identified as OBIAs,
SURTASS LFA sonar training and testing would be conducted such that
received levels of LFA sonar are below 180 dB re 1 [mu]Pa rms sound
pressure level (SPL). This restriction would be observed year-round for
coastal standoff zones and during known periods of biological
importance for OBIAs.
BILLING CODE 3510-22-P
[[Page 7190]]
[GRAPHIC] [TIFF OMITTED] TP01MR19.000
BILLING CODE 3510-22-C
For this rulemaking, the Navy has scoped the geographic extent of
its specified activities to better reflect the areas where the Navy
anticipates conducting SURTASS LFA sonar training and testing
activities now and into the reasonably foreseeable future. Fifteen
representative model areas (shown in Figure 1 and listed in Table 1),
with nominal modeling sites in each region, provide geographic context
for the proposed SURTASS LFA sonar activities.
Table 1--Representative SURTASS LFA Sonar Modeling Areas That the Navy Modeled for the DSEIS/OEIS (DoN, 2018)
and the MMPA Rulemaking/LOA Application
----------------------------------------------------------------------------------------------------------------
Location (latitude/ longitude of
Modeled site center of modeling area) Notes
----------------------------------------------------------------------------------------------------------------
East of Japan............................ 38[deg] N, 148[deg] E
North Philippine Sea..................... 29[deg] N, 136[deg] E
West Philippine Sea...................... 22[deg] N, 124[deg] E
Offshore Guam............................ 11[deg] N, 145[deg] E Navy Mariana Islands Testing and
Training Area.
Sea of Japan............................. 39[deg] N, 132[deg] E
East China Sea........................... 26[deg] N, 125[deg] E
South China Sea.......................... 14[deg] N, 114[deg] E
Offshore Japan 25[deg] to 40[deg] N...... 30[deg] N, 165[deg] E
Offshore Japan 10[deg] to 25[deg] N...... 15[deg] N, 165[deg] E
Hawaii North............................. 25[deg] N, 158[deg] W Navy Hawaii-Southern California
Training and Testing Area.
Hawaii South............................. 19.5[deg] N, 158.5[deg] W Navy Hawaii-Southern California
Training and Testing Area.
Offshore Sri Lanka....................... 5[deg] N, 85[deg] E
[[Page 7191]]
Andaman Sea.............................. 7.5[deg] N, 96[deg] E
Northwest of Australia................... 18[deg] S, 110[deg] E
Northeast of Japan....................... 52[deg] N, 163[deg] E
----------------------------------------------------------------------------------------------------------------
Detailed Description of the Specified Activities
SURTASS LFA Sonar--SONAR is an acronym for Sound Navigation and
Ranging, and its definition includes any system (biological or
mechanical) that uses underwater sound, or acoustics, for detection,
monitoring, and/or communications. Active sonar is the transmission of
sound energy for the purpose of sensing the environment by interpreting
features of received signals. Active sonar detects objects by creating
a sound pulse, or ``ping'' that is transmitted through the water and
reflects off the target, returning in the form of an echo. Passive
sonar detects the transmission of sound waves created by an object.
As mentioned previously, the SURTASS LFA sonar system is a long-
range, all-weather LF sonar (operating between 100 and 500 Hertz (Hz))
system that has both active and passive components. LFA, the active
system component (which allows for the detection of an object that is
not generating noise), is comprised of source elements (called
projectors) suspended vertically on a cable beneath the surveillance
vessel. The projectors produce an active sound pulse by converting
electrical energy to mechanical energy by setting up vibrations or
pressure disturbances within the water to produce a ping. The Navy uses
LFA as an augmentation to the passive SURTASS operations when passive
system performance is inadequate. SURTASS, the passive part of the
system, uses hydrophones (i.e., underwater microphones) to detect sound
emitted or reflected from submerged targets, such as submarines. The
SURTASS hydrophones are mounted on a horizontal line array that is
towed behind the surveillance vessel. The Navy processes and evaluates
the returning signals or echoes, which are usually below background or
ambient sound level, to identify and classify potential underwater
targets.
LFA Active Component--The active component of the SURTASS LFA sonar
system consists of up to 18 projectors suspended beneath the
surveillance vessel in a vertical line array. The SURTASS LFA sonar
projectors transmit in the low-frequency band (between 100 and 500 Hz).
The source level of an individual projector in the SURTASS LFA sonar
array is approximately 215 dB re: 1 [micro]Pa at 1 m or less. Sound
pressure is the sound force per unit area and is usually measured in
micropascals ([mu]Pa), where one Pascal (Pa) is the pressure resulting
from a force of one newton exerted over an area of one square meter.
The commonly used reference pressure level in underwater acoustics is 1
[mu]Pa at 1 m, and the units for source level are decibels (dB) re: 1
[mu]Pa at 1 m). Because of the physics involved in acoustic beamforming
(i.e., a method of mapping noise sources by differentiating sound
levels based upon the direction from which they originate) and sound
transmission loss processes, the SURTASS LFA sonar array cannot have a
SPL higher than the SPL of an individual projector.
The SURTASS LFA sonar acoustic transmission is an omnidirectional
beam (a full 360 degrees ([deg])) in the horizontal plane. The LFA
sonar system also has a narrow vertical beam that the vessel's crew can
steer above or below the horizontal plane. The typical SURTASS LFA
sonar signal is not a constant tone, but rather is a transmission of
various signal types that vary in frequency and duration (including
continuous wave (CW) and frequency-modulated (FM) signals). A complete
sequence of sound transmissions, also referred to by the Navy as a
``ping'' or a wavetrain, can be as short as six seconds (sec) or last
as long as 100 sec, with an average length of 60 sec. Within each ping,
the duration of any continuous frequency sound transmission is no
longer than 10 sec and the time between pings is typically from six to
15 minutes (min). Based on the Navy's historical operating parameters,
the average duty cycle (i.e., the ratio of sound ``on'' time to total
time) for LFA sonar is normally 7.5 to 10 percent and will not exceed a
maximum duty cycle of 20 percent.
Compact LFA Active Component--In addition to the LFA sonar system
currently deployed on the USNS IMPECCABLE, the Navy developed a compact
LFA (CLFA) sonar system, which is now deployed on its three smaller
surveillance vessels (i.e., the USNS ABLE, EFFECTIVE, and VICTORIOUS).
The operational characteristics of the active component for CLFA sonar
are comparable to the LFA system and the potential impacts from CLFA
will be similar to the effects from the LFA sonar system. The CLFA
sonar system consists of smaller projectors that weigh 142,000 lbs
(64,410 kilograms (kg)), which is 182,000 lbs (82,554 kg) less than the
weight of the LFA projectors on the USNS IMPECCABLE. The CLFA sonar
system also consists of up to 18 projectors suspended beneath the
surveillance vessel in a vertical line array and the CLFA sonar
projectors transmit in the low-frequency band (also between 100 and 500
Hz) with the same duty cycle as described for LFA sonar. Similar to the
active component of the LFA sonar system, the source level of an
individual projector in the CLFA sonar array is approximately 215 dB
re: 1 [micro]Pa or less.
For the analysis in this rulemaking, NMFS will use the term LFA to
refer to both the LFA sonar system and/or the CLFA sonar system, unless
otherwise specified.
SURTASS Passive Component--The passive component of the SURTASS LFA
sonar system consists of a SURTASS Twin-line (TL-29A) horizontal line
array mounted with hydrophones. The Y-shaped array is 1,000 ft (305 m)
in length and has an operational depth of 500 to 1,500 ft (152.4 to
457.2 m).
High-Frequency Marine Mammal Monitoring Active Sonar (HF/M3)--
Although technically not part of the SURTASS LFA sonar system, the Navy
also proposes to use a high-frequency sonar system, called the HF/M3
sonar, to detect and locate marine mammals
[[Page 7192]]
within the SURTASS LFA sonar mitigation and buffer zones, as described
later in this proposed rule. This enhanced commercial fish-finding
sonar, mounted at the top of the SURTASS LFA sonar vertical line array,
has a source level of 220 dB re: 1 [micro]Pa at 1 m with a frequency
range from 30 to 40 kilohertz (kHz). The duty cycle is variable, but is
normally below three to four percent and the maximum pulse duration is
40 milliseconds. The HF/M3 sonar has four transducers with 8[deg]
horizontal and 10[deg] vertical beamwidths, which sweep a full 360[deg]
in the horizontal plane every 45 to 60 sec with a maximum range of
approximately 1.2 mi (2 km).
Vessel Specifications--The Navy currently deploys SURTASS LFA sonar
on four twin-hulled ocean surveillance vessels that are 235 to 282 ft
(72 to 86 m) in length, with twin-shafted diesel electric engines
capable of providing 3,200 to 5,000 horsepower. Each vessel has an
observation area on the bridge that is more than 30 ft above sea level
from where lookouts will monitor for marine mammals whenever SURTASS
LFA sonar is transmitting. As stated previously, the Navy may develop
and field additional SURTASS LFA equipped vessels, either to replace or
complement the Navy's current SURTASS LFA capable fleet, and these
vessels may be in use beginning in the fifth year of the time period
covered by this proposed rulemaking.
The operational speed of each vessel during sonar activities will
be approximately 3.4 miles per hour (mph) (5.6 km per hour (km/hr); 3
knots (kt)) and each vessel's cruising speed outside of sonar
activities would be a maximum of approximately 11.5 to 14.9 mph (18.5
to 24.1 km/hr; 10 to 13 kts). During sonar activities, the SURTASS LFA
sonar vessels will generally travel in straight lines or in oval-shaped
(i.e., racetrack) patterns depending on the training or testing
scenario.
Notice of Receipt Comments and Responses
On July 13, 2018, NMFS published a notice of receipt (NOR) of an
application for rulemaking in the Federal Register (83 FR 32615) and
invited comments and information from the interested public. During the
30-day comment period, which ended on August 13, 2018, NMFS received
one comment from a private individual. This comment requested NMFS deny
the request to authorize the incidental take of marine mammals and stop
the Navy from performing SURTASS LFA sonar training and testing
activities, citing concern for assault and mortality of marine mammals.
As described below, no mortality of marine mammals is anticipated to
occur due to SURTASS LFA sonar activities. Therefore, the Navy has not
requested and NMFS is not proposing to authorize any mortality of
marine mammals. In addition, no injury (Level A harassment) is
anticipated as a result of the SURTASS LFA sonar training and testing
activities, so Navy has not requested nor has NMFS proposed authorizing
takes due to Level A harassment. Therefore, the incidental take of
marine mammals associated with the proposed SURTASS LFA sonar
activities would be limited to behavioral effects (Level B harassment).
Description of Marine Mammals in the Area of the Specified Activities
Forty-six species of marine mammals, including 10 baleen whale
(mysticete); 31 toothed whale (odontocete); and 5 seal/sea lion
(pinniped) species that represent 139 stocks (as currently classified)
have confirmed or possible occurrence within potential SURTASS LFA
sonar activity areas in the central and western North Pacific Ocean and
eastern Indian Ocean. Multiple stocks of some species are affected, and
independent assessments are conducted to make the necessary findings
and determinations for each of these.
There are 11 marine mammal species under NMFS' jurisdiction listed
as endangered or threatened under the Endangered Species Act (ESA; 16
U.S.C. 1531 et seq.) with confirmed or possible occurrence in the study
area for SURTASS LFA sonar training and testing activities. Marine
mammal species under NMFS' jurisdiction in the study area listed as
endangered are: North Pacific right whale (Eubalaena japonica); gray
whale (Eschrichtius robustus); blue whale (Balaenoptera musculus); fin
whale (Balaenoptera physalus); Western North Pacific distinct
population segment (DPS) of humpback whale (Megaptera novaeangliae);
sei whale (Balaenoptera borealis); sperm whale (Physeter
macrocephalus); Main Hawaiian Islands Insular DPS of false killer whale
(Pseudorca crassidens); Western DPS of the Steller sea lion (Eumetopias
jubatus); and Hawaiian monk seal (Neomonachus schauinslandi). The
southern DPS of the spotted seal (Phoca largha) is listed as threatened
under the ESA and is within the study area for SURTASS LFA sonar
activities. The aforementioned threatened and endangered marine mammal
species also are depleted under the MMPA.
Chinese river dolphins (Lipotes vexillifer) do not have stocks
designated within the SURTASS LFA sonar study area (see Potential
SURTASS LFA Study Area section). The distribution of the Chinese river
dolphin is limited to the main channel of a river section between the
cities of Jingzhou and Jiangyin. Based on the extremely rare occurrence
of these species in the Navy's Study Area and due to the coastal
standoff range (i.e., distance of 22 km (13 mi; 12 nmi) from land),
take of Chinese river dolphins is not considered a reasonable
likelihood; therefore, this species is not addressed further in this
document. Similarly, the Taiwanese humpback dolphin, a subspecies of
the Indo-Pacific humpback dolphin, is found only in a small, narrow
stretch of estuarine waters off the western coast of Taiwan. Take of
this species is also not considered a reasonable likelihood and this
species is not addressed further in this document.
None of the marine mammal species which the U.S. Fish and Wildlife
Service (USFWS) is responsible for managing occur in geographic areas
that would overlap with the SURTASS LFA sonar Study Area. Therefore,
the Navy has determined that SURTASS LFA sonar activities would have no
effect on the endangered or threatened species or the critical habitat
of the ESA-listed species under the jurisdiction of the USFWS. These
species are not considered further in this notice.
To accurately assess the potential effects of SURTASS LFA sonar
activities, the Navy modeled 15 representative sites in the SURTASS LFA
sonar activity area. Tables 2 through 16 (below) summarize the
abundance, status under the ESA, and density estimates of the marine
mammal species and stocks that have confirmed or possible occurrence
within the 15 SURTASS LFA sonar modeling areas in the central and
western North Pacific Ocean and eastern Indian Ocean.
[[Page 7193]]
Table 2--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 1, the East of Japan
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km\2\) \3\
Species Stock name \1\ Stock ---------------------------------------------------- ESA status
abundance \2\ Winter Spring Summer Fall \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale................................ WNP......................... 9,250 0.00001 0.00001 ........... 0.00001 EN
Bryde's whale............................. WNP......................... 20,501 0.0006 0.0006 0.0006 0.0006 NL
Common minke whale........................ WNP ``OE''.................. 25,049 0.0022 0.0022 0.0022 0.0022 NL
Fin whale................................. WNP......................... 9,250 ........... ........... 0.0002 0.0002 EN
Humpback whale............................ WNP stock and DPS........... 1,328 ........... ........... 0.00036 0.00036 EN
North Pacific right whale................. WNP......................... 922 0.00001 0.00001 ........... ........... EN
Sei whale................................. NP.......................... 7,000 0.0006 0.0006 0.0006 0.0006 EN
Baird's beaked whale...................... WNP......................... 5,688 ........... ........... 0.0029 0.0029 NL
Common dolphin............................ WNP......................... 3,286,163 0.0761 0.0761 0.0761 0.0761 NL
Common bottlenose dolphin................. WNP Northern Offshore....... 100,281 0.0171 0.0171 0.0171 0.0171 NL
Cuvier's beaked whale..................... WNP......................... 90,725 0.0031 0.0031 0.0031 0.0031 NL
Dall's porpoise (truei)................... WNP truei................... 178,157 0.0390 0.0520 ........... 0.0520 NL
False killer whale........................ WNP......................... 16,668 0.0036 0.0036 0.0036 0.0036 NL
Ginkgo-toothed beaked whale............... NP.......................... 22,799 0.0005 0.0005 0.0005 0.0005 NL
Harbor porpoise........................... WNP......................... 31,046 0.0190 0.0190 0.0190 0.0190 NL
Hubbs beaked whale........................ NP.......................... 22,799 0.0005 0.0005 0.0005 0.0005 NL
Killer whale.............................. WNP......................... 12,256 0.0001 0.0001 0.0001 0.0001 NL
Kogia spp. \5\............................ WNP......................... 350,553 0.0031 0.0031 0.0031 0.0031 NL
Pacific white-sided dolphin............... NP.......................... 931,000 0.0082 0.0082 0.0082 0.0082 NL
Pantropical spotted dolphin............... WNP......................... 130,002 ........... ........... 0.0259 0.0259 NL
Pygmy killer whale........................ WNP......................... 30,214 0.0021 0.0021 0.0021 0.0021 NL
Risso's dolphin........................... WNP......................... 143,374 0.0097 0.0097 0.0097 0.0097 NL
Rough-toothed dolphin..................... WNP......................... 5,002 0.00224 0.00224 0.00224 0.00224 NL
Short-finned pilot whale.................. WNP Northern................ 20,884 0.0128 0.0128 0.0128 0.0128 NL
Sperm whale............................... NP.......................... 102,112 0.00123 0.00123 0.00123 0.00123 EN
Spinner dolphin........................... WNP......................... 1,015,059 ........... ........... 0.00083 0.00083 NL
Stejneger's beaked whale.................. WNP......................... 8,000 0.0005 0.0005 0.0005 0.0005 NL
Striped dolphin........................... WNP Northern Offshore....... 497,725 0.0111 0.0111 0.0111 0.0111 NL
Northern fur seal......................... WP.......................... 503,609 0.368 0.158 ........... ........... ..........
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ NP=north Pacific; OE=Offshore Japan; WP=western Pacific; WNP=western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the model area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
\5\ Pygmy and dwarf sperm whales are difficult to distinguish at sea, and abundance estimates are pooled for Kogia spp. as reported in Ferguson and
Barlow, 2001 and 2003.
Table 3--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 2, North Philippine Sea
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km\2\) \3\
Species Stock name \1\ Abundance \2\ ---------------------------------------------------- ESA status
Winter Spring Summer Fall \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale................................ WNP......................... 9,250 0.00001 0.00001 ........... 0.00001 EN
Bryde's whale............................. WNP......................... 20,501 0.0006 0.0006 0.0006 0.0006 NL
Common minke whale........................ WNP ``OE''.................. 25,049 0.0044 0.0044 0.0044 0.0044 NL
Fin whale................................. WNP......................... 9,250 0.0002 0.0002 ........... ........... EN
Humpback whale............................ WNP and DPS................. 1,328 0.00089 0.00089 ........... .00089 EN
North Pacific right whale................. WNP......................... 922 0.00001 0.00001 ........... ........... EN
Omura's whale............................. WNP......................... 1,800 0.00004 0.00004 0.00004 0.00004 NL
Blainville's beaked whale................. WNP......................... 8,032 0.0005 0.0005 0.0005 0.0005 NL
Common dolphin............................ WNP......................... 3,286,163 0.0562 0.0562 0.0562 0.0562 NL
Common bottlenose dolphin................. Japanese Coastal............ 3,516 0.0146 0.0146 0.0146 0.0146 NL
Cuvier's beaked whale..................... WNP......................... 90,725 0.0054 0.0054 0.0054 0.0054 NL
False killer whale........................ WNP......................... 16,668 0.0029 0.0029 0.0029 0.0029 NL
Fraser's dolphin.......................... WNP......................... 220,789 0.0069 0.0069 0.0069 0.0069 NL
Ginkgo-toothed beaked whale............... NP.......................... 22,799 0.0005 0.0005 0.0005 0.0005 NL
Killer whale.............................. WNP......................... 12,256 0.00009 0.00009 0.00009 0.00009 NL
Kogia spp. \5\............................ WNP......................... 350,553 0.0031 0.0031 0.0031 0.0031 NL
Longman's beaked whale.................... WNP......................... 7,619 0.00025 0.00025 0.00025 0.00025 NL
Melon-headed whale........................ WNP......................... 56,213 0.00428 0.00428 0.00428 0.00428 NL
Pacific white-sided dolphin............... NP.......................... 931,000 0.0119 0.0119 ........... ........... NL
Pantropical spotted dolphin............... WNP......................... 130,002 0.0137 0.0137 0.0137 0.0137 NL
Pygmy killer whale........................ WNP......................... 30,214 0.0021 0.0021 0.0021 0.0021 NL
Risso's dolphin........................... WNP......................... 143,374 0.0106 0.0106 0.0106 0.0106 NL
Rough-toothed dolphin..................... WNP......................... 5,002 0.00224 0.00224 0.00224 0.00224 NL
Short-finned pilot whale.................. WNP Southern................ 31,396 0.0153 0.0153 0.0153 0.0153 NL
Sperm whale............................... NP.......................... 102,112 0.00123 0.00123 0.00123 0.00123 EN
Spinner dolphin........................... WNP......................... 1,015,059 0.00083 0.00083 0.00083 0.00083 NL
Striped dolphin........................... Japanese Coastal............ 19,631 0.0329 0.0329 0.0329 0.0329 NL
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ NP=north Pacific; OE=Offshore Japan; WNP=western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the mission area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
[[Page 7194]]
\5\ Pygmy and dwarf sperm whales are difficult to distinguish at sea, and abundance estimates are pooled for Kogia spp. as reported in Ferguson and
Barlow, 2001 and 2003.
Table 4--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 3, West Philippine Sea
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km\2\) \3\
Species Stock name \1\ Abundance \2\ ---------------------------------------------------- ESA status
Winter Spring Summer Fall \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale................................ WNP......................... 9,250 0.00001 0.00001 ........... 0.00001 EN
Bryde's whale............................. WNP......................... 20,501 0.0006 0.0006 0.0006 0.0006 NL
Common minke whale........................ WNP ``OE''.................. 25,049 0.0033 0.0033 0.0033 0.0033 NL
Fin whale................................. WNP......................... 9,250 0.0002 0.0002 ........... ........... EN
Humpback whale............................ WNP and DPS................. 1,328 0.00089 0.00089 ........... 0.00089 EN
Omura's whale............................. WNP......................... 1,800 0.00004 0.00004 0.00004 0.00004 NL
Blainville's beaked whale................. WNP......................... 8,032 0.0005 0.0005 0.0005 0.0005 NL
Common dolphin............................ WNP......................... 3,286,163 0.1158 0.1158 0.1158 0.1158 NL
Common bottlenose dolphin................. WNP Southern Offshore....... 40,769 0.0146 0.0146 0.0146 0.0146 NL
Cuvier's beaked whale..................... WNP......................... 90,725 0.0003 0.0003 0.0003 0.0003 NL
Deraniyagala's beaked whale............... NP.......................... 22,799 0.0005 0.0005 0.0005 0.0005 NL
False killer whale........................ WNP......................... 16,668 0.0029 0.0029 0.0029 0.0029 NL
Fraser's dolphin.......................... WNP......................... 220,789 0.0069 0.0069 0.0069 0.0069 NL
Ginkgo-toothed beaked whale............... NP.......................... 22,799 0.0005 0.0005 0.0005 0.0005 NL
Killer whale.............................. WNP......................... 12,256 0.00009 0.00009 0.00009 0.00009 NL
Kogia spp. \5\............................ WNP......................... 350,553 0.0017 0.0017 0.0017 0.0017 *
Longman's beaked whale.................... WNP......................... 7,619 0.00025 0.00025 0.00025 0.00025 NL
Melon-headed whale........................ WNP......................... 56,213 0.00428 0.00428 0.00428 0.00428 NL
Pantropical spotted dolphin............... WNP......................... 130,002 0.0137 0.0137 0.0137 0.0137 NL
Pygmy killer whale........................ WNP......................... 30,214 0.0021 0.0021 0.0021 0.0021 NL
Risso's dolphin........................... WNP......................... 143,374 0.0106 0.0106 0.0106 0.0106 NL
Rough-toothed dolphin..................... WNP......................... 5,002 0.00224 0.00224 0.00224 0.00224 NL
Short-finned pilot whale.................. WNP Southern................ 31,396 0.0076 0.0076 0.0076 0.0076 NL
Sperm whale............................... NP.......................... 102,112 0.00123 0.00123 0.00123 0.00123 EN
Spinner dolphin........................... WNP......................... 1,015,059 0.00083 0.00083 0.00083 0.00083 NL
Striped dolphin........................... WNP Southern Offshore....... 52,682 0.0164 0.0164 0.0164 0.0164 NL
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ NP=north Pacific; OE=Offshore Japan; WNP=western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the model area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
\5\ Pygmy and dwarf sperm whales are difficult to distinguish at sea, and abundance estimates are pooled for Kogia spp. as reported in Ferguson and
Barlow, 2001 and 2003.
Table 5--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 4, Offshore Guam
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km\2\) \3\
Species Stock name \1\ Abundance \2\ ---------------------------------------------------- ESA status
Winter Spring Summer Fall \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale................................ WNP......................... 9,250 0.00001 0.00001 ........... 0.00001 EN
Bryde's whale............................. WNP......................... 20,501 0.0004 0.0004 0.0004 0.0004 NL
Common minke whale........................ WNP ``OE''.................. 25,049 0.00015 0.00015 0.00015 0.00015 NL
Fin whale................................. WNP......................... 9,250 0.00001 0.00001 ........... 0.00001 EN
Humpback whale............................ WNP and DPS................. 1,328 0.00089 0.00089 ........... 0.00089 EN
Omura's whale............................. WNP......................... 1,800 0.00004 0.00004 0.00004 0.00004 NL
Sei whale................................. NP.......................... 7,000 0.00029 0.00029 ........... 0.00029 EN
Blainville's beaked whale................. WNP......................... 8,032 0.00086 0.00086 0.00086 0.00086 NL
Common bottlenose dolphin................. WNP Southern Offshore....... 40,769 0.00899 0.00899 0.00899 0.00899 NL
Cuvier's beaked whale..................... WNP......................... 90,725 0.0003 0.0003 0.0003 0.0003 NL
Deraniyagala's beaked whale............... NP.......................... 22,799 0.00093 0.00093 0.00093 0.00093 NL
Dwarf sperm whale......................... WNP......................... 350,553 0.00714 0.00714 0.00714 0.00714 NL
False killer whale........................ WNP......................... 16,668 0.00111 0.00111 0.00111 0.00111 NL
Fraser's dolphin.......................... CNP......................... 16,992 0.02104 0.02104 0.02104 0.02104 NL
Ginkgo-toothed beaked whale............... NP.......................... 22,799 0.00093 0.00093 0.00093 0.00093 NL
Killer whale.............................. WNP......................... 12,256 0.00006 0.00006 0.00006 0.00006 NL
Longman's beaked whale.................... WNP......................... 7,619 0.00311 0.00311 0.00311 0.00311 NL
Melon-headed whale........................ WNP......................... 56,213 0.00428 0.00428 0.00428 0.00428 NL
Pantropical spotted dolphin............... WNP......................... 130,002 0.0226 0.0226 0.0226 0.0226 NL
Pygmy killer whale........................ WNP......................... 30,214 0.00014 0.00014 0.00014 0.00014 NL
Pygmy sperm whale......................... WNP......................... 350,553 0.00291 0.00291 0.00291 0.00291 NL
Risso's dolphin........................... WNP......................... 143,374 0.00474 0.00474 0.00474 0.00474 NL
Rough-toothed dolphin..................... WNP......................... 5,002 0.00185 0.00185 0.00185 0.00185 NL
Short-finned pilot whale.................. WNP Southern................ 31,396 0.00797 0.00797 0.00797 0.00797 NL
Sperm whale............................... NP.......................... 102,112 0.00123 0.00123 0.00123 0.00123 EN
Spinner dolphin........................... WNP......................... 1,015,059 0.00083 0.00083 0.00083 0.00083 NL
Striped dolphin........................... WNP Southern Offshore....... 52,682 0.00616 0.00616 0.00616 0.00616 NL
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ CNP=central north Pacific; NP=north Pacific; OE=Offshore Japan; WNP=western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the mission area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
[[Page 7195]]
Table 6--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 5, Sea of Japan
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km\2\) \3\
Species Stock name \1\ Abundance ---------------------------------------------------- ESA Status \4\
\2\ Winter Spring Summer Fall
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bryde's whale........................... WNP....................... 20,501 0.0001 0.0001 0.0001 0.0001 NL
Common minke whale...................... WNP ``JW'' Stock.......... 2,611 0.00016 0.00016 0.00016 0.00016 NL
Fin whale............................... WNP....................... 9,250 0.0009 0.0009 ........... 0.0009 EN
North Pacific right whale............... WNP....................... 922 0.00001 0.00001 ........... ........... EN
Omura's whale........................... WNP....................... 1,800 0.00004 0.00004 0.00004 0.00004 NL
Western North Pacific gray whale........ WNP Western DPS........... 140 0.00001 0.00001 0.00001 0.00001 EN \5\
Baird's beaked whale.................... WNP....................... 5,688 0.0003 0.0003 ........... 0.0003 NL
Common dolphin.......................... WNP....................... 279,182 0.1158 0.1158 0.1158 0.1158 NL
Common bottlenose dolphin............... IA........................ 105,138 0.00077 0.00077 0.00077 0.00077 NL
Cuvier's beaked whale................... WNP....................... 90,725 0.0031 0.0031 0.0031 0.0031 NL
Dall's porpoise......................... SOJ dalli................. 173,638 0.0520 0.0520 ........... 0.0520 NL
False killer whale...................... IA........................ 9,777 0.0027 0.0027 0.0027 0.0027 NL
Harbor porpoise......................... WNP....................... 31,046 0.0190 0.0190 ........... 0.0190 NL
Killer whale............................ WNP....................... 12,256 0.00009 0.00009 0.00009 0.00009 NL
Kogia spp \6\........................... WNP....................... 350,553 0.0017 0.0017 0.0017 0.0017 *
Pacific white-sided dolphin............. NP........................ 931,000 0.0030 0.0030 ........... ........... NL
Risso's dolphin......................... IA........................ 143,374 0.0073 0.0073 0.0073 0.0073 NL
Rough-toothed dolphin................... WNP....................... 5,002 0.00224 0.00224 0.00224 0.00224 NL
Sperm whale............................. NP........................ 102,112 0.00123 0.00123 0.00123 0.00123 EN
Spinner dolphin......................... WNP....................... 1,015,059 ........... ........... 0.00083 0.00083 NL
Stejneger's beaked whale................ WNP....................... 8,000 0.0005 0.0005 0.0005 0.0005 NL
Northern fur seal....................... WP........................ 503,609 0.368 0.158 ........... ........... ...................
Spotted seal............................ Southern and DPS.......... 3,500 0.00001 0.00001 0.00001 0.00001 T
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ IA=Inshore Archipelago; JW=Sea of Japan (minke); NP=north Pacific; SOJ=Sea of Japan; WNP=western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the model area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
\5\ Only the western Pacific population of gray whale is endangered under the ESA.
\6\ Pygmy and dwarf sperm whales are difficult to distinguish at sea, and abundance estimates are pooled for Kogia spp as reported in Ferguson and
Barlow, 2001 and 2003.
Table 7--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 6, East China Sea
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km\2\) \3\
Species Stock name \1\ Abundance \2\ ---------------------------------------------------- ESA status \4\
Winter Spring Summer Fall
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bryde's whale......................... ECS...................... 137 0.0003 0.0003 0.0003 0.0003 NL
Common minke whale.................... YS....................... 4,492 0.0018 0.0018 0.0018 0.0018 NL
Fin whale............................. ECS...................... 500 0.0002 0.0002 0.0002 0.0002 EN
North Pacific right whale............. WNP...................... 922 0.00001 0.00001 ........... ........... EN
Omura's whale......................... WNP...................... 1,800 0.00004 0.00004 0.00004 0.00004 NL
Western North Pacific gray whale...... WNP and Western DPS...... 140 0.00001 0.00001 ........... 0.00001 EN \5\
Blainville's beaked whale............. WNP...................... 8,032 0.0005 0.0005 0.0005 0.0005 NL
Common dolphin........................ WNP...................... 279,182 0.1158 0.1158 0.1158 0.1158 NL
Common bottlenose dolphin............. IA....................... 105,138 0.00077 0.00077 0.00077 0.00077 NL
Cuvier's beaked whale................. WNP...................... 90,725 0.0003 0.0003 0.0003 0.0003 NL
False killer whale.................... IA....................... 9,777 0.00111 0.00111 0.00111 0.00111 NL
Fraser's dolphin...................... WNP...................... 220,789 0.00694 0.00694 0.00694 0.00694 NL
Ginkgo-toothed beaked whale........... NP....................... 22,799 0.0005 0.0005 0.0005 0.0005 NL
Killer whale.......................... WNP...................... 12,256 0.00009 0.00009 0.00009 0.00009 NL
Kogia spp \6\......................... WNP...................... 350,553 0.0017 0.0017 0.0017 0.0017 *
Longman's beaked whale................ WNP...................... 7,619 0.00025 0.00025 0.00025 0.00025 NL
Melon-headed whale.................... WNP...................... 56,213 0.00428 0.00428 0.00428 0.00428 NL
Pacific white-sided dolphin........... NP....................... 931,000 0.0028 0.0028 ........... ........... NL
Pantropical spotted dolphin........... WNP...................... 130,002 0.01374 0.01374 0.01374 0.01374 NL
Pygmy killer whale.................... WNP...................... 30,214 0.00014 0.00014 0.00014 0.00014 NL
Risso's dolphin....................... IA....................... 143,374 0.0106 0.0106 0.0106 0.0106 NL
Rough-toothed dolphin................. WNP...................... 5,002 0.00224 0.00224 0.00224 0.00224 NL
Sperm whale........................... NP....................... 102,112 0.00123 0.00123 0.00123 0.00123 EN
Spinner dolphin....................... WNP...................... 1,015,059 0.00083 0.00083 0.00083 0.00083 NL
Spotted seal.......................... Southern and DPS......... 1,000 0.00001 0.00001 0.00001 0.00001 T
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ECS=East China Sea; IA=Inshore Archipelago; NP=north Pacific; WNP=western north Pacific; YS=Yellow Sea.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the mission area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
\5\ Only the western Pacific population of gray whale is endangered under the ESA.
\6\ Pygmy and dwarf sperm whales are difficult to distinguish at sea, and abundance estimates are pooled for Kogia spp. as reported in Ferguson and
Barlow, 2001 and 2003.
[[Page 7196]]
Table 8--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 7, South China Sea
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km\2\) \3\
Species Stock name \1\ Abundance \2\ ---------------------------------------------------- ESA status \4\
Winter Springer Summer Fall
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bryde's whale......................... WNP...................... 20,501 0.0006 0.0006 0.0006 0.0006 NL
Common minke whale.................... YS....................... 4,492 0.0018 0.0018 0.0018 0.0018 NL
Fin whale............................. WNP...................... 9,250 0.0002 0.0002 ........... 0.0002 EN
Humpback whale........................ WNP and DPS.............. 1,328 0.00036 0.00036 ........... 0.00036 EN
North Pacific right whale............. WNP...................... 922 0.00001 0.00001 ........... ........... EN
Omura's whale......................... WNP...................... 1,800 0. 00004 0. 00004 0. 00004 0. 00004 NL
Western North Pacific gray whale...... WNP and Western DPS...... 140 0.00001 0.00001 ........... 0.00001 EN \5\
Blainville's beaked whale............. WNP...................... 8,032 0.0005 0.0005 0.0005 0.0005 NL
Common dolphin........................ WNP...................... 279,182 0.1158 0.1158 0.1158 0.1158 NL
Common bottlenose dolphin............. IA....................... 105,138 0.00077 0.00077 0.00077 0.00077 NL
Cuvier's beaked whale................. WNP...................... 90,725 0.0003 0.0003 0.0003 0.0003 NL
Deraniyagala's beaked whale........... NP....................... 22,799 0.0005 0.0005 0.0005 0.0005 NL
False killer whale.................... IA....................... 9,777 0.00111 0.00111 0.00111 0.00111 NL
Fraser's dolphin...................... WNP...................... 220,789 0.00694 0.00694 0.00694 0.00694 NL
Ginkgo-toothed beaked whale........... NP....................... 22,799 0.0005 0.0005 0.0005 0.0005 NL
Killer whale.......................... WNP...................... 12,256 0.00009 0.00009 0.00009 0.00009 NL
Kogia spp \6\......................... WNP...................... 350,553 0.0017 0.0017 0.0017 0.0017 *
Longman's beaked whale................ WNP...................... 7,619 0.00025 0.00025 0.00025 0.00025 NL
Melon-headed whale.................... WNP...................... 56,213 0.00428 0.00428 0.00428 0.00428 NL
Pantropical spotted dolphin........... WNP...................... 130,002 0.01374 0.01374 0.01374 0.01374 NL
Pygmy killer whale.................... WNP...................... 30,214 0.00014 0.00014 0.00014 0.00014 NL
Risso's dolphin....................... IA....................... 143,374 0.0106 0.0106 0.0106 0.0106 NL
Rough-toothed dolphin................. WNP...................... 5,002 0.00224 0.00224 0.00224 0.00224 NL
Short-finned pilot whale.............. WNP Southern............. 31,396 0.00159 0.00159 0.00159 0.00159 NL
Sperm whale........................... NP....................... 102,112 0.0012 0.0012 0.0012 0.0012 EN
Spinner dolphin....................... WNP...................... 1,015,059 0.00083 0.00083 0.00083 0.00083 NL
Striped dolphin....................... WNP Southern Offshore.... 52,682 0.00584 0.00584 0.00584 0.00584 NL
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ IA=Inshore Archipelago; NP=north Pacific; WNP=western north Pacific; YS=Yellow Sea.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the model area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
\5\ Only the western Pacific population of gray whale is endangered under the ESA.
\6\ Pygmy and dwarf sperm whales are difficult to distinguish at sea, and abundance estimates are pooled for Kogia spp. as reported in Ferguson and
Barlow, 2001 and 2003.
Table 9--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 8, Offshore Japan 25[deg]
to 40[deg] N
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km\2\) \3\
Species Stock name \1\ Abundance \2\ ---------------------------------------------------- ESA status
Winter Spring Summer Fall \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale................................ WNP......................... 9,250 0.00001 0.00001 ........... 0.00001 EN
Bryde's whale............................. WNP......................... 20,501 0.0003 0.0003 0.0003 0.0003 NL
Common minke whale........................ WNP ``OE''.................. 25,049 0.0003 0.0003 0.0003 0.0003 NL
Fin whale................................. WNP......................... 9,250 ........... ........... 0.0001 0.0001 EN
Humpback whale............................ WNP and DPS................. 1,328 ........... ........... 0.00036 0.00036 EN
Sei whale................................. NP.......................... 7,000 ........... 0.00029 0.00029 0.00029 EN
Baird's beaked whale...................... WNP......................... 5,688 0.0001 0.0001 0.0001 0.0001 NL
Blainville's beaked whale................. WNP......................... 8,032 0.0007 0.0007 0.0007 0.0007 NL
Common dolphin............................ WNP......................... 3,286,163 0.0863 0.0863 0.0863 0.0863 NL
Common bottlenose dolphin................. WNP Northern Offshore....... 100,281 0.00077 0.00077 0.00077 0.00077 NL
Cuvier's beaked whale..................... WNP......................... 90,725 0.00374 0.00374 0.00374 0.00374 NL
Dall's porpoise........................... WNP dalli................... 162,000 0.0390 0.0520 ........... 0.0520 ..........
Dwarf sperm whale......................... WNP......................... 350,553 0.0043 0.0043 0.0043 0.0043 NL
False killer whale........................ WNP......................... 16,668 0.0036 0.0036 0.0036 0.0036 NL
Hubb's beaked whale....................... NP.......................... 22,799 0.0005 0.0005 0.0005 0.0005 NL
Killer whale.............................. WNP......................... 12,256 0.00009 0.00009 0.00009 0.00009 NL
Longman's beaked whale.................... WNP......................... 7,619 0.00025 0.00025 0.00025 0.00025 NL
Melon-headed whale........................ WNP......................... 56,213 0.0027 0.0027 0.0027 0.0027 NL
Mesoplodon spp \5\........................ WNP......................... 22,799 0.0005 0.0005 0.0005 0.0005 NL
Northern right whale dolphin.............. NP.......................... 68,000 0.00001 0.00001 ........... 0.00001 NL
Pacific white-sided dolphin............... NP.......................... 931,000 0.0048 0.0048 0.0048 0.0048 NL
Pantropical spotted dolphin............... WNP......................... 130,002 0.0113 0.0113 0.0113 0.0113 NL
Pygmy killer whale........................ WNP......................... 30,214 0.0001 0.0001 0.0001 0.0001 NL
Pygmy sperm whale......................... WNP......................... 350,553 0.0018 0.0018 0.0018 0.0018 NL
Risso's dolphin........................... WNP......................... 143,374 0.0005 0.0005 0.0005 0.0005 NL
Rough-toothed dolphin..................... WNP......................... 5,002 0.0019 0.0019 0.0019 0.0019 NL
Short-finned pilot whale.................. WNP Northern................ 20,884 0.0021 0.0021 0.0021 0.0021 NL
Sperm whale............................... NP.......................... 102,112 0.0022 0.0022 0.0022 0.0022 EN
Spinner dolphin........................... WNP......................... 1,015,059 0.0019 0.0019 0.0019 0.0019 NL
Stejneger's beaked whale.................. WNP......................... 8,000 0.0005 0.0005 0.0005 0.0005 NL
Striped dolphin........................... WNP Northern Offshore....... 497,725 0.0058 0.0058 0.0058 0.0058 NL
Hawaiian monk seal........................ Hawaii...................... 1,427 0.00001 0.00001 0.00001 0.00001 EN
[[Page 7197]]
Northern fur seal......................... WP.......................... 503,609 0.0123 ........... ........... ........... NL
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ NP=north Pacific; OE=Offshore Japan; WNP=western north Pacific; WP=Western Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the mission area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
\5\ No methods are available to distinguish between the species of Mesoplodon beaked whales in the WNP stocks (Blainville's beaked whale (M.
densirostris), Perrin's beaked whale (M. perrini), Lesser beaked whale (M. peruvianus), Stejneger's beaked whale (M. stejnegeri), Gingko-toothed
beaked whale (M. gingkodens), and Hubbs' beaked whale (M. carlhubbsi)) when observed during at-sea surveys (Carretta et al., 2018). As reported in
Ferguson and Barlow, 2001 and 2003, data on these species were pooled. These six species are managed as one unit.
Table 10--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 9, Offshore Japan 10[deg]
to 25[deg] N
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km \2\) \3\
Species Stock name \1\ Abundance \2\ ---------------------------------------------------- ESA status \4\
Winter Spring Summer Fall
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale............................ WNP...................... 9,250 0.00001 0.00001 ........... 0.00001 EN
Bryde's whale......................... WNP...................... 20,501 0.0003 0.0003 0.0003 0.0003 NL
Fin whale............................. WNP...................... 9,250 0.00001 0.00001 ........... ........... EN
Humpback whale........................ WNP and DPS.............. 1,328 0.00036 0.00036 ........... 0.00036 EN
Omura's whale......................... WNP...................... 1,800 0.00004 0.00004 0.00004 0.00004 NL
Sei whale............................. NP....................... 7,000 0.0029 ........... ........... 0.0029 EN
Blainville's beaked whale............. WNP...................... 8,032 0.0007 0.0007 0.0007 0.0007 NL
Common bottlenose dolphin............. WNP Southern Offshore.... 40,769 0.00077 0.00077 0.00077 0.00077 NL
Cuvier's beaked whale................. WNP...................... 90,725 0.00374 0.00374 0.00374 0.00374 NL
Deraniyagala's beaked whale........... NP....................... 22,799 0.00093 0.00093 0.00093 0.00093 NL
Dwarf sperm whale..................... WNP...................... 350,553 0.0043 0.0043 0.0043 0.0043 NL
False killer whale.................... WNP...................... 16,668 0.00057 0.00057 0.00057 0.00057 NL
Fraser's dolphin...................... CNP...................... 16,992 0.00251 0.00251 0.00251 0.00251 NL
Ginkgo-toothed beaked whale........... NP....................... 22,799 0.00093 0.00093 0.00093 0.00093 NL
Killer whale.......................... WNP...................... 12,256 0.00009 0.00009 0.00009 0.00009 NL
Longman's beaked whale................ WNP...................... 7,619 0.00025 0.00025 0.00025 0.00025 NL
Melon-headed whale.................... WNP...................... 56,213 0.00267 0.00267 0.00267 0.00267 NL
Pantropical spotted dolphin........... WNP...................... 130,002 0.01132 0.01132 0.01132 0.01132 NL
Pygmy killer whale.................... WNP...................... 30,214 0.00006 0.00006 0.00006 0.00006 NL
Pygmy sperm whale..................... WNP...................... 350,553 0.00176 0.00176 0.00176 0.00176 NL
Risso's dolphin....................... WNP...................... 143,374 0.00046 0.00046 0.00046 0.00046 NL
Rough-toothed dolphin................. WNP...................... 5,002 0.00185 0.00185 0.00185 0.00185 NL
Short-finned pilot whale.............. WNP Southern............. 31,396 0.00211 0.00211 0.00211 0.00211 NL
Sperm whale........................... NP....................... 102,112 0.00222 0.00222 0.00222 0.00222 EN
Spinner dolphin....................... WNP...................... 1,015,059 0.00187 0.00187 0.00187 0.00187 NL
Striped dolphin....................... WNP Southern Offshore.... 52,682 0.00584 0.00584 0.00584 0.00584 NL
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ NP=north Pacific; CNP=central north Pacific; WNP=western north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the model area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
Table 11--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 10, Northern Hawaii
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km \2\) \3\
Species Stock name \1\ Abundance \2\ ---------------------------------------------------- ESA status \4\
Winter Spring Summer Fall
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale............................ CNP...................... 133 0.00005 0.00005 ........... 0.00005 EN
Bryde's whale......................... Hawaii................... 1,751 0.000085 0.000085 0.000085 0.000085 NL
Common minke whale.................... Hawaii................... 25,049 0.00423 0.00423 ........... 0.00423 NL
Fin whale............................. Hawaii................... 154 0.00006 0.00006 ........... 0.00006 EN
Humpback whale........................ CNP and Hawaii DPS....... 10,103 0.00529 0.00529 ........... 0.00529 NL
Sei whale............................. Hawaii................... 391 0.00016 0.00016 ........... 0.00016 EN
Blainville's beaked whale............. Hawaii................... 2,105 0.00086 0.00086 0.00086 0.00086 NL
Common bottlenose dolphin............. Hawaii pelagic........... 21,815 0.00118 0.00118 0.00118 0.00118 NL
Kauai/Niihau............. 184 0.065 0.065 0.065 0.065 NL
4 Islands................ 191 0.017 0.017 0.017 0.017 NL
Oahu..................... 743 0.187 0.187 0.187 0.187 NL
Hawaii Island............ 128 0.028 0.028 0.028 0.028 NL
Cuvier's beaked whale................. Hawaii................... 723 0.0003 0.0003 0.0003 0.0003 NL
Dwarf sperm whale..................... Hawaii................... 17,519 0.00714 0.00714 0.00714 0.00714 NL
False killer whale.................... Hawaii-Pelagic........... 1,540 0.0006 0.0006 0.0006 0.0006 NL
Main HI Islands Insular 167 0.0008 0.0008 0.0008 0.0008 EN
and DPS.
NW HI Islands............ 617 0.0006 0.0006 0.0006 0.0006 NL
Fraser's dolphin...................... Hawaii................... 51,491 0.02104 0.02104 0.02104 0.02104 NL
[[Page 7198]]
Killer whale.......................... Hawaii................... 146 0.00006 0.00006 0.00006 0.00006 NL
Longman's beaked whale................ Hawaii................... 7,619 0.00311 0.00311 0.00311 0.00311 NL
Melon-headed whale.................... Hawaiian Islands......... 8,666 0.002 0.0020 0.0020 0.0020 NL
Kohala Resident.......... 447 0.1000 0.1000 0.1000 0.1000 NL
Pantropical spotted dolphin........... Hawaiian Pelagic......... 55,795 0.00369 0.00369 0.00369 0.00369 NL
Hawaiian Island.......... 220 0.061 0.061 0.061 0.061 NL
Oahu..................... 220 0.072 0.072 0.072 0.072 NL
4 Islands................ 220 0.061 0.061 0.061 0.061 NL
Pygmy killer whale.................... Hawaii................... 10,640 0.00435 0.00435 0.00435 0.00435 NL
Pygmy sperm........................... Hawaii................... 7,138 0.0029 0.0029 0.0029 0.0029 NL
Risso's dolphin....................... Hawaii................... 11,613 0.00474 0.00474 0.00474 0.00474 NL
Rough-toothed dolphin................. Hawaii................... 72,528 0.00224 0.00224 0.00224 0.00224 NL
Short-finned pilot whale.............. Hawaii................... 19,503 0.00459 0.00459 0.00459 0.00459 NL
Sperm whale........................... Hawaii................... 4,559 0.00158 0.00158 0.00158 0.00158 EN
Spinner dolphin....................... Hawaii Pelagic........... 3,351 0.00159 0.00159 0.00159 0.00159 NL
Kauai/Niihau............. 601 0.097 0.097 0.097 0.097 NL
Hawaiian Island.......... 631 0.066 0.066 0.066 0.066 NL
Oahu/4 Islands........... 355 0.023 0.023 0.023 0.023 NL
Kure/Midway Atoll........ 260 0.0070 0.0070 0.0070 0.0070 NL
Pearl and Hermes Reef.... 300 0.0070 0.0070 0.0070 0.0070 NL
Striped dolphin....................... Hawaii................... 61,201 0.00385 0.00385 0.00385 0.00385 NL
Hawaiian monk seal.................... Hawaii................... 1,427 0.00004 0.00004 0.00004 0.00004 EN
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ CNP=central north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the mission area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
Table 12--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 11, Southern Hawaii
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km \2\) \3\
Species Stock name \1\ Abundance \2\ ---------------------------------------------------- ESA status \4\
Winter Spring Summer Fall
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale............................ CNP...................... 133 0.00005 0.00005 ........... 0.00005 EN
Bryde's whale......................... Hawaii................... 798 0.00012 0.00012 0.00012 0.00012 NL
Common minke whale.................... Hawaii................... 25,049 0.00423 0.00423 ........... 0.00423 NL
Fin whale............................. Hawaii................... 154 0.00006 0.00006 ........... 0.00006 EN
Humpback whale........................ CNP/Hawaii DPS........... 10,103 0.00631 0.00631 ........... 0.00631 NL
Sei whale............................. Hawaii................... 391 0.00016 0.00016 ........... 0.00016 EN
Blainville's beaked whale............. Hawaii................... 2,105 0.00086 0.00086 0.00086 0.00086 NL
Common bottlenose dolphin............. Hawaii Pelagic........... 21,815 0.00126 0.00126 0.00126 0.00126 NL
Oahu..................... 743 0.187 0.187 0.187 0.187 NL
4 Islands................ 191 0.017 0.017 0.017 0.017 NL
Hawaii Island............ 128 0.028 0.028 0.028 0.028 NL
Kauai/Niihau............. 184 0.065 0.065 0.065 0.065 NL
Cuvier's beaked whale................. Hawaii................... 723 0.0003 0.0003 0.0003 0.0003 NL
Deraniyagala's beaked whale........... NP....................... 22,799 0.00093 0.00093 0.00093 0.00093 NL
Dwarf sperm whale..................... Hawaii................... 17,519 0.00714 0.00714 0.00714 0.00714 NL
False killer whale.................... Hawaii-Pelagic........... 1,540 0.00086 0.00086 0.00086 0.00086 NL
Main Hawaiian Island 167 0.0008 0.0008 0.0008 0.0008 EN
Insular.
Fraser's dolphin...................... Hawaii................... 51,491 0.02104 0.02104 0.02104 0.02104 NL
Killer whale.......................... Hawaii................... 146 0.00006 0.00006 0.00006 0.00006 NL
Longman's beaked whale................ Hawaii................... 7,619 0.00311 0.00311 0.00311 0.00311 NL
Melon-headed whale.................... Hawaiian Islands......... 8,666 0.0020 0.0020 0.0020 0.0020 NL
Kohala Resident.......... 447 0.1000 0.1000 0.1000 0.1000 NL
Pantropical spotted dolphin........... Hawaiian Pelagic......... 55,795 0.00541 0.00541 0.00541 0.00541 NL
Hawaii Island............ 220 0.061 0.061 0.061 0.061 NL
Oahu..................... 220 0.072 0.072 0.072 0.072 NL
4 Islands................ 220 0.061 0.061 0.061 0.061 NL
Pygmy killer whale.................... Hawaii................... 10,640 0.00435 0.00435 0.00435 0.00435 NL
Pygmy sperm whale..................... Hawaii................... 7,138 0.0029 0.0029 0.0029 0.0029 NL
Risso's dolphin....................... Hawaii................... 11,613 0.00474 0.00474 0.00474 0.00474 NL
Rough toothed dolphin................. Hawaii................... 75,528 0.00257 0.00257 0.00257 0.00257 NL
Short-finned pilot whale.............. Hawaii................... 19,503 0.00549 0.00549 0.00549 0.00549 NL
Sperm whale........................... Hawaii................... 4,559 0.00131 0.00131 0.00131 0.00131 EN
Spinner dolphin....................... Hawaii Pelagic........... 3,351 0.00348 0.00348 0.00348 0.00348 NL
Oahu/4-Islands........... 601 0.023 0.023 0.023 0.023 NL
Hawaii Island............ 631 0.066 0.066 0.066 0.066 NL
Kauai/Niihau............. 355 0.097 0.097 0.097 0.097 .................
Striped dolphin....................... Hawaii................... 61,201 0.00475 0.00475 0.00475 0.00475 NL
Hawaiian monk seal.................... Hawaii................... 1,427 0.00004 0.00004 0.00004 0.00004 EN
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ CNP=central north Pacific; NP=north Pacific.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
[[Page 7199]]
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the model area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
Table 13--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 12, Offshore Sri Lanka
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km\2\) \3\
Species Stock name \1\ Abundance \2\ ---------------------------------------------------- ESA status \4\
Winter Spring Summer Fall
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale............................ NIND..................... 3,691 0.00004 0.00004 0.00004 0.00004 EN
Bryde's whale......................... NIND..................... 9,176 0.00041 0.00041 0.00041 0.00041 NL
Common minke whale.................... IND...................... 257,000 0.00001 0.00001 0.00001 0.00001 NL
Fin whale............................. IND...................... 1,846 0.00001 0.00001 0.00001 0.00001 EN
Omura's whale......................... NIND..................... 9,176 0.00041 0.00041 0.00041 0.00041 NL
Sei whale............................. NIND..................... 9,176 0.00041 0.00041 0.00041 0.00041 EN
Blainville's beaked whale............. IND...................... 16,867 0.00105 0.00105 0.00105 0.00105 NL
Common dolphin........................ IND...................... 1,819,982 0.00513 0.00516 0.00541 0.00538 NL
Common bottlenose dolphin............. NIND..................... 785,585 0.04839 0.04829 0.04725 0.04740 NL
Cuvier's beaked whale................. NIND..................... 27,272 0.00506 0.00508 0.00505 0.00505 NL
Deraniyagala's beaked whale........... IND...................... 16,867 0.00513 0.00516 0.00541 0.00538 NL
Dwarf sperm whale..................... IND...................... 10,541 0.00005 0.00005 0.00005 0.00005 NL
False killer whale.................... IND...................... 144,188 0.00024 0.00024 0.00024 0.00024 NL
Fraser's dolphin...................... IND...................... 151,554 0.00207 0.00207 0.00207 0.00207 NL
Indo-Pacific bottlenose dolphin....... IND...................... 7,850 0.00048 0.00048 0.00047 0.00047 NL
Killer whale.......................... IND...................... 12,593 0.00697 0.00155 0.00693 0.00694 NL
Longman's beaked whale................ IND...................... 16,867 0.00513 0.00516 0.00541 0.00538 NL
Melon-headed whale.................... IND...................... 64,600 0.00921 0.00920 0.00937 0.00936 NL
Pantropical spotted dolphin........... IND...................... 736,575 0.00904 0.00904 0.00904 0.00904 NL
Pygmy killer whale.................... IND...................... 22,029 0.00138 0.00137 0.00152 0.00153 NL
Pygmy sperm whale..................... IND...................... 10,541 0.00001 0.00001 0.00001 0.00001 NL
Risso's dolphin....................... IND...................... 452,125 0.08641 0.08651 0.08435 0.08466 NL
Rough-toothed dolphin................. IND...................... 156,690 0.00071 0.00071 0.00071 0.00071 NL
Short-finned pilot whale.............. IND...................... 268,751 0.03219 0.03228 0.03273 0.03279 NL
Sperm whale........................... NIND..................... 24,446 0.00129 0.00118 0.00126 0.00121 EN
Spinner dolphin....................... IND...................... 634,108 0.00678 0.00678 0.00678 0.00678 NL
Striped dolphin....................... IND...................... 674,578 0.14601 0.14629 0.14780 0.14788 NL
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ IND=Indian Ocean; NIND=northern Indian Ocean.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the mission area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
Table 14--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 13, Andaman Sea
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km\2\) \3\
Species Stock name \1\ Abundance \2\ ---------------------------------------------------- ESA status \4\
Winter Spring Summer Fall
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale............................ NIND..................... 3,691 0.00003 0.00003 0.00003 0.00003 EN
Bryde's whale......................... NIND..................... 9,176 0.00038 0.000036 0.00037 0.00037 NL
Common minke whale.................... IND...................... 257,000 ........... 0.00001 0.00968 0.00001 NL
Fin whale............................. IND...................... 1,846 0.00001 0.00001 ........... 0.00001 EN
Omura's whale......................... NIND..................... 9,176 0.00038 0.00036 0.00037 0.00037 NL
Blainville's beaked whale............. IND...................... 16,867 0.00094 0.00089 0.00094 0.00099 NL
Common bottlenose dolphin............. NIND..................... 785,585 0.07578 0.07781 0.07261 0.07212 NL
Cuvier's beaked whale................. NIND..................... 27,272 0.00466 0.00482 0.00480 0.00473 NL
Deraniyagala's beaked whale........... IND...................... 16,867 0.00094 0.00092 0.00097 0.00099 NL
Dwarf sperm whale..................... IND...................... 10,541 0.00005 0.00006 0.00006 0.00005 NL
False killer whale.................... IND...................... 144,188 0.00023 0.00023 0.00024 0.00023 NL
Fraser's dolphin...................... IND...................... 151,554 0.00176 0.00179 0.00180 0.00180 NL
Ginkgo-toothed beaked whale........... IND...................... 16,867 0.00094 0.00092 0.00097 0.00099 NL
Indo-Pacific bottlenose dolphin....... IND...................... 7,850 0.00076 0.00078 0.00073 0.00072 NL
Killer whale.......................... IND...................... 12,593 0.00744 0.00178 0.00730 0.00734 NL
Longman's beaked whale................ IND...................... 16,867 0.00444 0.00429 0.00459 0.00440 NL
Melon-headed whale.................... IND...................... 64,600 0.00884 0.00884 0.00878 0.00846 NL
Pantropical spotted dolphin........... IND...................... 736,575 0.00868 0.00841 0.00829 0.00873 NL
Pygmy killer whale.................... IND...................... 22,029 0.00121 0.00113 0.00125 0.00131 NL
Pygmy sperm whale..................... IND...................... 10,541 0.00001 0.00001 0.00001 0.00001 NL
Risso's dolphin....................... IND...................... 452,125 0.09197 0.09215 0.09173 0.09366 NL
Rough-toothed dolphin................. IND...................... 156,690 0.00077 0.00078 0.00077 0.00074 NL
Short-finned pilot whale.............. IND...................... 268,751 0.03354 0.03364 0.03543 0.03504 NL
Sperm whale........................... NIND..................... 24,446 0.00109 0.00099 0.00107 0.00105 EN
Spinner dolphin....................... IND...................... 634,108 0.00736 0.00711 0.00701 0.00726 NL
Striped dolphin....................... IND...................... 674,578 0.14413 0.14174 0.14123 0.14402 NL
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ IND=Indian Ocean; NIND=northern Indian Ocean.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the model area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
[[Page 7200]]
Table 15--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 14, Northwestern
Australia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km\2\) \3\
Species Stock name \1\ Abundance \2\ ---------------------------------------------------- ESA status \4\
Winter Spring Summer Fall
--------------------------------------------------------------------------------------------------------------------------------------------------------
Antarctic minke whale................. ANT...................... 90,000 ........... 0.00001 0.00001 0.00001 NL
Blue whale/Pygmy blue whale........... SIND..................... 1,657 ........... 0.00003 0.00003 0.00003 EN
Bryde's whale......................... SIND..................... 13,854 0.00032 0.00032 0.00032 0.00032 NL
Common minke whale.................... IND...................... 257,500 ........... 0.01227 0.01929 0.01947 NL
Fin whale............................. SIND..................... 38,185 0.00001 0.00099 0.00128 0.00121 EN
Humpback whale........................ Western Australia stock 13,640 ........... 0.00007 0.00007 0.00007 NL
and DPS.
Omura's whale......................... SIND..................... 13,854 0.00032 0.00032 0.00032 0.00032 NL
Sei whale............................. SIND..................... 13,854 0.00001 0.00001 0.00001 0.00001 EN
Blainville's beaked whale............. IND...................... 16,867 0.00083 0.00083 0.00082 0.00083 NL
Common bottlenose dolphin............. WAU...................... 3,000 0.03630 0.03652 0.03459 0.03725 NL
Cuvier's beaked whale................. SH....................... 76,500 0.00399 0.00406 0.00402 0.00405 NL
Dwarf sperm whale..................... IND...................... 10,541 0.00004 0.00004 0.00004 0.00004 NL
False killer whale.................... IND...................... 144,188 0.00020 0.00020 0.00019 0.00020 NL
Fraser's dolphin...................... IND...................... 151,554 0.00145 0.00148 0.00149 0.00147 NL
Killer whale.......................... IND...................... 12,593 0.00585 0.00435 0.00588 0.00580 NL
Longman's beaked whale................ IND...................... 16,867 0.00393 0.00393 0.00403 0.00412 NL
Melon-headed whale.................... IND...................... 64,600 0.00717 0.00717 0.00635 0.00637 NL
Pantropical spotted dolphin........... IND...................... 736,575 0.00727 0.00727 0.00715 0.00746 NL
Pygmy killer whale.................... IND...................... 22,029 0.00100 0.00104 0.00101 0.00097 NL
Risso's dolphin....................... IND...................... 452,125 0.07152 0.07214 0.06944 0.07173 NL
Rough-toothed dolphin................. IND...................... 156,690 0.00059 0.00060 0.00059 0.00059 NL
Short-finned pilot whale.............. IND...................... 268,751 0.02698 0.02759 0.02689 0.02716 NL
Southern bottlenose whale............. IND...................... 599,300 0.00083 0.00083 0.00082 0.00083 NL
Spade-toothed beaked whale............ IND...................... 16,867 0.00083 0.00083 0.00082 0.00083 NL
Sperm whale........................... SIND..................... 24,446 0.00096 0.00087 0.00097 0.00092 EN
Spinner dolphin....................... IND...................... 634,108 0.00561 0.00549 0.00568 0.00563 NL
Striped dolphin....................... IND...................... 674,578 0.12018 0.12041 0.11680 0.11727 NL
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ANT=Antarctic; SIND=southern Indian Ocean; IND=Indian Ocean; SH=Southern Hemisphere; WAU=Western Australia.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the mission area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
Table 16--Abundance and Density Estimates for the Marine Mammal Species, Species Groups, and Stocks Associated With Model Area 15, Northeast of Japan
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density (animals/km\2\) \3\
Species Stock name \1\ Abundance \2\ ---------------------------------------------------- ESA status \4\
Winter Spring Summer Fall
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale............................ WNP...................... 9,250 0.00001 0.00001 ........... 0.00001 EN
Common minke whale.................... WNP ``OE''............... 25,049 0.0022 0.0022 0.0022 0.0022 NL
Fin whale............................. WNP...................... 9,250 ........... 0.0002 0.0002 0.0002 EN
Humpback whale........................ WNP and DPS.............. 1,328 ........... 0.000498 0.000498 0.000498 EN
North Pacific right whale............. WNP...................... 922 ........... ........... 0.00001 0.00001 EN
Sei whale............................. NP....................... 7,000 ........... 0.00029 0.00029 ........... EN
Western North Pacific gray whale...... Western and DPS.......... 140 ........... ........... 0.00001 0.00001 EN
Baird's beaked whale.................. WNP...................... 5,688 ........... 0.0015 0.0029 0.0029 NL
Common dolphin........................ WNP...................... 3,286,163 0.0863 0.0863 0.0863 0.0863 NL
Cuvier's beaked whale................. WNP...................... 90,725 0.0054 0.0054 0.0054 0.0054 NL
Dall's porpoise....................... WNP dalli................ 162,000 0.0390 0.0520 0.0650 0.0520 NL
Killer whale.......................... WNP...................... 12,256 0.0036 0.0036 0.0036 0.0036 NL
Pacific white-sided dolphin........... NP....................... 931,000 0.0048 0.0048 0.0048 0.0048 NL
Sperm whale........................... NP....................... 102,112 0.0017 0.0022 0.0022 0.0022 EN
Stejneger's beaked whale.............. WNP...................... 8,000 0.0005 0.0005 0.0005 0.0005 NL
Northern fur seal..................... Western Pacific.......... 503,609 0.00689 0.01378 0.01378 0.01378 NL
Ribbon seal........................... NP....................... 365,000 0.0904 0.0904 0.0452 0.0452 NL
Spotted seal.......................... Alaska/Bering Sea DPS.... 461,625 ........... 0.2770 0.1385 ........... NL
Steller sea lion...................... West-Asian and Western 71,221 0.00001 0.00001 0.00001 0.00001 EN
DPS.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ IND=Indian Ocean; NP=northern Pacific; WNP=western north Pacific; OE=Offshore Japan.
\2\ Refer to Table 3-2 of the Navy's application for literature references associated with abundance estimates presented in this table.
\3\ Refer to Table 3-2 of the Navy's application for literature references associated with density estimates presented in this table. No value for
density indicates that species is not expected to occur in the model area during that season.
\4\ ESA Status: EN=Endangered; T=Threatened; NL=Not Listed.
Information on how the density and abundance stock estimates were
derived for the selected mission sites is in the Navy's application
(refer to section 3.2). These data are derived from the best available
published source documentation and provide general area information for
each model area with species-specific information on the animals that
could occur in that area, including estimates for their stock,
abundance, and density. The Navy developed the abundance and density
estimates by first using estimates from line-transect surveys that
occurred in or near each of the 15 model sites (e.g., Bradford et al.,
2017). When density estimates were not available from a survey in the
model area, the Navy extrapolated density estimates from a region with
similar oceanographic
[[Page 7201]]
characteristics to that model area. For example, the eastern tropical
Pacific has been extensively surveyed and provides a comprehensive
understanding of marine mammals in temperate oceanic waters (Ferguson
and Barlow, 2001, 2003). Density estimates for some model areas were
also derived from the Navy's Marine Species Density Database (DoN,
2018). In addition, density estimates are usually not available for
rare marine mammal species or for those that have been newly defined
(e.g., the Deraniyagala's beaked whale). For these species, the lowest
density estimate of 0.0001 animals/square kilometer (0.0001 animals/
km\2\) was used in the take analysis to reflect the low probability of
occurrence in a specific SURTASS LFA sonar model area. Further, the
Navy pooled density estimates for species of the same genus if
sufficient data were not available to compute a density for individual
species or the species are difficult to distinguish at sea, which is
often the case for beaked whales (e.g., Mesoplodon spp.), as well as
the pygmy and dwarf sperm whales (Kogia spp.). Density estimates are
available for species groups rather than the individual species for
Kogia spp. in model areas 1, 2, 3, 5, 6, and 7 and for Mesoplodon spp.
in model area 8, as the best available data (Ferguson and Barlow, 2001
and 2003) were reported as pooled data.
The Navy provides detailed descriptions of the distribution,
abundance, diving behavior, life history, and hearing vocalization
information for each affected marine mammal species with confirmed or
possible occurrence within SURTASS LFA sonar study areas in section 4
(pages 4-1 through 4-44) of the application, which is available online
at https://www.fisheries.noaa .gov/national/marine-mammal-protection/
incidental-take-authorizations-military-readiness-activities.
Although not repeated in this document, NMFS has reviewed these
data, determined them to be the best available scientific information
for the proposed rulemaking, and considers this information part of the
administrative record for this action. Additional information is
available in NMFS' Marine Mammal Stock Assessment Reports, which may be
viewed at https://www.fisheries.noaa .gov/national/marine-mammal-
protection/marine-mammal-stock-assessments. NMFS refers the public to
Table 3-2 (pages 3-6 through 3-25) of the Navy's application for
literature references associated with abundance and density estimates
presented in these tables.
Brief Background on Sound, Marine Mammal Hearing, and Vocalization
Underwater Sound
An understanding of the basic properties of underwater sound is
necessary to comprehend many of the concepts and analyses presented in
this document. Sound travels in waves, the basic components of which
are frequency, wavelength, velocity, and amplitude. Sound frequency is
measured in cycles per second, referred to as Hertz (Hz), and is
analogous to musical pitch; high-pitched sounds contain high
frequencies and low-pitched sounds contain low frequencies. Frequency,
or the ``pitch'' of a sound, is the number of pressure waves that pass
by a reference point per unit of time and is measured in Hz or cycles
per second. Wavelength is the distance between two peaks or
corresponding points of a sound wave (length of one cycle). Higher
frequency sounds have shorter wavelengths than lower frequency sounds,
and typically attenuate (decrease) more rapidly, except in certain
cases in shallower water. Amplitude is the height of the sound pressure
wave or the ``loudness'' of a sound and is typically described using
the relative unit of the dB. A sound pressure level (SPL) in dB is
described as the ratio between a measured pressure and a reference
pressure (for underwater sound, this is 1 microPascal ([mu]Pa)) and is
a logarithmic unit that accounts for large variations in amplitude;
therefore, a relatively small change in dB corresponds to large changes
in sound pressure. The source level (SL) represents the SPL referenced
at a distance of 1 m from the source (referenced to 1 [mu]Pa), while
the received level is the SPL at the listener's position (referenced to
1 [mu]Pa).
Natural sounds in the ocean span a large range of frequencies: From
earthquake noise at five Hz to harbor porpoise clicks at 150,000 Hz
(150 kilohertz (kHz)). These sounds are so low or so high in pitch that
humans cannot even hear them; acousticians call these infrasonic
(typically below 20 Hz, which is considered the low frequency bound of
human hearing) and ultrasonic (typically above 20,000 Hz, which is
considered the upper bound of human hearing) sounds, respectively. A
single sound may be made up of multiple frequencies. Sounds made up of
only a small range of frequencies are called narrowband, and sounds
with a broad range of frequencies are called broadband. Explosives are
an example of a broadband sound source and tactical military sonars are
an example of a narrowband sound source.
When underwater objects vibrate or activity occurs, sound-pressure
waves are created. These waves alternately compress and decompress the
water as the sound wave travels. Underwater sound waves radiate in a
manner similar to ripples on the surface of a pond and may be either
directed in a beam or beams or may radiate in all directions
(omnidirectional sources), as is the case for sound produced by LFA
sonar. The compressions and decompressions associated with sound waves
are detected as changes in pressure by aquatic life and man-made sound
receptors such as hydrophones.
Sounds are often considered to fall into one of two general types:
Impulsive and non-impulsive (described below). The distinction between
these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward, 1997 in Southall et al., 2007). Please see
Southall et al. (2007) for an in-depth discussion of these concepts.
The distinction between these two sound types is not always obvious, as
certain signals share properties of both pulsed and non-pulsed sounds.
A signal near a source could be categorized as a pulse, but due to
propagation effects as it moves farther from the source, the signal
duration becomes longer (e.g., Greene and Richardson, 1988).
Impulsive sound sources (e.g., airguns, explosions, gunshots, sonic
booms, impact pile driving) produce signals that are brief (typically
considered to be less than one second), broadband, atonal transients
(ANSI, 1986, 2005; Harris, 1998; NIOSH, 1998; ISO, 2003) and occur
either as isolated events or repeated in some succession. Impulsive
sounds are all characterized by a relatively rapid rise from ambient
pressure to a maximal pressure value followed by a rapid decay period
that may include a period of diminishing, oscillating maximal and
minimal pressures, and generally have an increased capacity to induce
physical injury as compared with sounds that lack these features.
Non-impulsive sounds can be tonal, narrowband, or broadband, brief
or prolonged, and may be either continuous or intermittent (ANSI, 1995;
NIOSH, 1998). Some of these non-impulsive sounds can be transient
signals of short duration but without the essential properties of
pulses (e.g., rapid rise time). Examples of non-impulsive sounds
include those produced by vessels, aircraft, machinery operations such
as drilling or dredging, and vibratory pile driving. The duration of
such sounds, as received at a distance,
[[Page 7202]]
can be greatly extended in a highly reverberant environment. Given the
non-pulsed nature of the LFA sonar source, it is appropriate to
consider it a non-impulsive source for estimation of permanent and
temporary threshold shifts (PTS and TTS, respectively). The Navy
derived the potential for Level B harassment directly from data
obtained during experiments exposing marine mammals (mysticetes) to low
frequency sonar. Refer to the ``Estimated Take'' section for more
information regarding the estimation of take by harassment.
Metrics Used in This Document
This section includes a brief explanation of the sound measurement
metrics frequently used in the discussions of acoustic effects in this
document.
Sound Pressure Level
Sound pressure level (SPL) is expressed as the ratio of a measured
sound pressure and a reference level. The commonly used reference
pressure level in underwater acoustics is 1 [mu]Pa, and the units for
SPLs are decibels (dB) re: 1 [mu]Pa. SPL (in dB) = 20 log (pressure/
reference pressure). SPL is an instantaneous measurement and can be
expressed as the peak (pk), the peak-peak (p-p), or the root mean
square (RMS). SPL does not directly take the duration of exposure to a
sound into account, though the duration over which the root mean square
pressure is averaged should be noted since it influences the result.
Root mean square pressure, which is the square root of the arithmetic
average of the squared instantaneous pressure values (Urick, 1983), is
typically used in discussions of behavioral effects of sounds on
vertebrates in part because behavioral effects, which often result from
auditory cues, may be better expressed through averaged units than by
peak pressures. SPLpk is applicable to impulsive, or pulsed,
noise (such as airguns, explosions, gunshots, sonic booms, and impact
pile driving); as such it is not applicable to SURTASS LFA sonar and
therefore is not used for estimation of PTS (Level A harassment) in
this rulemaking. All references to SPL in this document refer to the
RMS unless otherwise noted. In addition, the Navy uses a Single Ping
Equivalent (SPE) metric for the estimation of Level B harassment, as
described below.
Cumulative Sound Exposure Level
Sound exposure level (SEL; represented as dB re 1 [mu]Pa\2\-s)
represents the total energy contained within a pulse, and considers
both exposure level and duration of exposure.
To assess potential for auditory injury of marine mammals from
sound exposure, NMFS' 2018 Revision to Technical Guidance for Assessing
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Acoustic
Technical Guidance) identifies specific injury thresholds for impulsive
and non-impulsive sources, and divides marine mammals into hearing
groups based on measured or estimated generalized hearing ranges. The
Acoustic Technical Guidance uses a dual metric approach for impulsive
sounds (i.e., peak SPL (SPLpk) and cumulative SEL
(SELcum)), but since SURTASS LFA sonar is a non-impulsive
source, only the cumulative SELcum metric is used to account
for the total energy received over the specified duration of sound
exposure (i.e., the metric accounts for both received level and
duration of exposure) (Southall et al., 2007; NMFS, 2018). NMFS'
Acoustic Technical Guidance builds upon the foundation provided by
Southall et al. (2007), while incorporating updated information that
since became available on marine mammal hearing and impacts of noise on
hearing (e.g., DoN, 2017). NMFS (2018) recommends 24 hours as the
default maximum accumulation period relative to SELcum
thresholds.
Note that NMFS' SELcum acoustic thresholds also
incorporate marine mammal auditory weighting functions, which take into
account what is known about marine mammal hearing sensitivity and
susceptibility to noise-induced hearing loss, and can be applied to a
sound-level measurement to account for frequency-dependent hearing
(NMFS, 2018). See Houser (2017) for a review of the development of
auditory weighting functions for marine mammals. For further discussion
of auditory weighting functions and their application or metrics
associated with evaluating noise-induced hearing loss, see also NMFS
(2018).
Table 17 displays auditory impact thresholds for onset of temporary
and permanent threshold shifts (TTS and PTS, respectively) in hearing
(from NMFS (2018)).
Table 17--TTS and PTS Onset Thresholds for Non-Impulsive Sounds \1\
------------------------------------------------------------------------
Cumulative sound Cumulative sound
Hearing group exposure level exposure level
for TTS \1\ (dB) for PTS \1\ (dB)
------------------------------------------------------------------------
Low-frequency cetaceans........... 179 199
Mid-frequency cetaceans........... 178 198
High-frequency cetaceans.......... 153 173
Phoicid pinnipeds (PW) 181 201
(Underwater).....................
Otariid pinnipeds (OW) 199 219
(Underwater).....................
------------------------------------------------------------------------
\1\ Referenced to 1 [mu]Pa\2\s; weighted according to appropriate
auditory weighting function.
Single Ping Equivalent (SPE)
To model potential behavioral impacts to marine animals from
exposure to SURTASS LFA sonar sound, the Navy has developed a
methodology to estimate the total exposure of modeled animals exposed
to multiple pings over an extended period of time. The Navy's acoustic
model analyzes the following components: (1) The LFA sonar source
modeled as a point source, with an effective source level (SL) of
approximately 240 dB re: 1 [mu]Pa at 1 m (SPL); (2) a 60-sec duration
signal; and (3) a beam pattern that is correct for the number and
spacing of the individual projectors (source elements). This source
model, when combined with the three-dimensional transmission loss (TL)
field generated by the Parabolic Equation (PE) acoustic propagation
model, defines the received level (RL) (in SPL) sound field surrounding
the source for a 60-sec LFA sonar signal (i.e., the SPE metric accounts
for received level and exposure from multiple pings). To estimate the
total exposure of animals exposed to multiple pings, the Navy models
the RLs for each modeled location and any computer-simulated marine
mammals (animats) within the location, records the exposure history of
each animat, and generates a SPE value. Thus, the Navy can model the
SURTASS LFA sound
[[Page 7203]]
field, providing a four-dimensional (position and time) representation
of a sound pressure field within the marine environment and estimates
of an animal's exposure to sound over a period of 24 hours.
Figure 2 shows the Navy calculation that converts SPL values to SPE
values in order to estimate impacts to marine mammals from SURTASS LFA
sonar transmissions. For a more detailed explanation of the SPE
calculations, NMFS refers the public to Appendix B of the SURTASS 2018
DSEIS/SOEIS.
[GRAPHIC] [TIFF OMITTED] TP01MR19.001
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Current data indicate that not all marine
mammal species have equal hearing capabilities (e.g., Richardson et
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect
this, Southall et al. (2007) recommended that marine mammals be divided
into functional hearing groups based on directly measured or estimated
hearing ranges on the basis of available behavioral response data,
audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. Note that no direct measurements
of hearing ability have been successfully completed for mysticetes
(i.e., low-frequency cetaceans).
Subsequently, NMFS (2018) described generalized hearing ranges for
these marine mammal hearing groups. Generalized hearing ranges were
chosen based on the approximately 65 dB threshold from the normalized
composite audiograms, with an exception for lower limits for low-
frequency cetaceans where the result was deemed to be biologically
implausible, and the lower bound from Southall et al. (2007) was
retained while the lower frequency range for phocid pinnipeds was
approximated. The generalized hearing groups and the associated
frequencies are indicated below (note that these frequency ranges
correspond to the range for the composite group, with the entire range
not necessarily reflecting the capabilities of every species within
that group):
Low-frequency (LF) cetaceans (mysticetes): Generalized
hearing is estimated to occur between approximately 7 Hz and 35 kHz;
Mid-frequency (MF) cetaceans (larger toothed whales,
beaked whales, and most delphinids): Generalized hearing is estimated
to occur between approximately 150 Hz and 160 kHz;
High-frequency (HF) cetaceans (porpoises, river dolphins,
and members of the genera Kogia and Cephalorhynchus; including two
members of the genus Lagenorhynchus, on the basis of recent
echolocation data and genetic data): Generalized hearing is estimated
to occur between approximately 275 Hz and 160 kHz;
Pinnipeds in water; Phocidae (true seals): Generalized
hearing is estimated to occur between approximately 50 Hz to 86 kHz;
Pinnipeds in water; Otariidae (eared seals): Generalized
hearing is estimated to occur between 60 Hz and 39 kHz for Otariidae.
Marine Mammal Hearing Groups and LFA Sonar
Baleen (mysticete) whales (members of the LF hearing group) have
inner ears that appear to be specialized for low-frequency hearing.
Conversely, most odontocetes (i.e., dolphins and porpoises) have inner
ears that are specialized to hear mid and high frequencies. Pinnipeds,
which lack the highly specialized active biosonar systems of
odontocetes, have inner ears that are specialized to hear a broad range
of frequencies in water (Southall et al., 2007 and NMFS, 2018). Based
on measured hearing thresholds, the LFA sound source is below the range
of known highest hearing sensitivity for MF and HF odontocetes and
pinnipeds in water (Au, 1993; Au and Hastings, 2008; Gentry, 2009; Hall
and Johnson, 1972; Houser et al., 2008; Kastelein et al., 2009, 2005,
2003, and 2002; Montie et al., 2011; Mooney et al., 2015; Mulsow and
Reichmuth, 2010; Nedwell et al., 2004; Richardson et al., 1995;
Ridgeway and Carder, 2001; Pacini et al., 2011; Schlundt et al., 2011;
Sills et al., 2014; Southall et al., 2007; Szymanski et al., 1999;
Thomas et al., 1990; Yuen et al., 2005).
Marine Mammal Vocalization
Marine mammal vocalizations often extend both above and below the
range of human hearing (higher than 20 kHz and lower than 20 Hz;
Research Council, 2003). Measured data on the hearing abilities of
cetaceans are sparse or non-existent, particularly for the larger
cetaceans such as the baleen whales (mysticetes). The auditory
thresholds of some of the smaller odontocetes have been determined in
captivity. It is generally believed that cetaceans should at least be
sensitive to the frequencies of their own vocalizations and those of
conspecifics (i.e., an organism of the same or similar species).
Comparisons of the anatomy of cetacean inner ears and models of the
structural properties and the response to vibrations of the ear's
components in different species provide an indication of likely
sensitivity to various sound frequencies. Thus, the ears of small
toothed whales are optimized for receiving high-frequency sound, while
baleen whale inner ears are best suited for low frequencies, including
to infrasonic frequencies (Ketten, 1992; 1994; 1997; 1998).
Baleen whale (i.e., mysticete) vocalizations are composed primarily
of frequencies below one kHz, and some contain fundamental frequencies
as low as 16 Hz (Watkins et al., 1987; Richardson et al., 1995; Rivers,
1997;
[[Page 7204]]
Moore et al., 1998; Stafford et al., 1999; Wartzok and Ketten, 1999)
but can be as high as 24 kHz (humpback whale; Au et al., 2006). Clark
and Ellison (2004) suggested that baleen whales use low frequency
sounds not only for long-range communication, but also as a simple form
of echo ranging, using echoes to navigate and orient relative to
physical features of the ocean. Information on auditory function in
mysticetes is limited. Sensitivity to low frequency sound by baleen
whales has been inferred from observed vocalization frequencies,
observed reactions to playback of sounds, and anatomical analyses of
the auditory system. Although there is apparently much variation, the
source levels of most baleen whale vocalizations lie in the range of
150-190 dB re: 1 [mu]Pa at 1 m. Low-frequency vocalizations made by
baleen whales and their corresponding auditory anatomy suggest that
they have good low-frequency hearing (Ketten, 2000), although specific
data on sensitivity, frequency or intensity discrimination, or
localization abilities are lacking. Marine mammals, like all mammals,
have typical U-shaped audiograms that begin with relatively low
sensitivity (high threshold) at some specified low frequency with
increased sensitivity (low threshold) to a species-specific optimum
followed by a generally steep rise at higher frequencies (high
threshold) (Fay, 1988).
Toothed whales (i.e., odontocetes) produce a wide variety of
sounds, which include species-specific broadband ``clicks'' with peak
energy between 10 and 200 kHz, individually variable ``burst pulse''
click trains, and constant frequency or frequency-modulated (FM)
whistles ranging from 4 to 16 kHz (Wartzok and Ketten, 1999). The
general consensus is that the tonal vocalizations (whistles) produced
by toothed whales play an important role in maintaining contact between
dispersed individuals, while broadband clicks are used during
echolocation (Wartzok and Ketten, 1999). Burst pulses have also been
strongly implicated in communication, with some scientists suggesting
that they play an important role in agonistic encounters (McCowan and
Reiss, 1995), while others have proposed that they represent
``emotive'' signals in a broader sense, possibly representing graded
communication signals (Herzing, 1996). Sperm whales, however, are known
to produce only clicks, which are used for both communication and
echolocation (Whitehead, 2003). Most of the energy of toothed whales'
(i.e., odontocetes) social vocalizations is concentrated near 10 kHz,
with source levels for whistles as high as 100-180 dB re 1 [mu]Pa at 1
m (Richardson et al., 1995). No odontocete has been shown
audiometrically to have acute hearing (less than 80 dB re 1 [mu]Pa at 1
m) below 500 Hz (DoN, 2001; Ketten, 1998). Sperm whales produce clicks,
which may be used to echolocate (Mullins et al., 1988), with a
frequency range from less than 100 Hz to 30 kHz and source levels up to
230 dB re 1 [mu]Pa at 1 m or greater (Mohl et al., 2000).
Potential Effects of the Specified Activity on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activities (e.g., use of acoustic sources)
may impact marine mammals and their habitat. The ``Estimated Take''
section later in this document includes a quantitative analysis of the
number of individuals that are expected to be taken by this activity.
The ``Negligible Impact Analysis and Determination'' section considers
the content of this section and the material it references, the
``Estimated Take'' section, and the ``Proposed Mitigation'' section to
draw conclusions regarding the likely impacts of these activities on
the reproductive success or survivorship of individuals and how those
impacts on individuals are likely to impact marine mammal species or
stocks.
The Navy has requested authorization for the incidental take of
marine mammals that may result from upcoming use of SURTASS LFA sonar
during training and testing activities on U.S. Naval ships in certain
areas of the central and western North Pacific Ocean and eastern Indian
Ocean. In addition to the use of LFA and HF/M3 sonar, the Navy has
analyzed the potential impact of ship strike to marine mammals from
SURTASS LFA sonar activities and, in consultation with NMFS as a
cooperating agency for the SURTASS LFA sonar 2018 DSEIS/SOEIS, has
determined that take of marine mammals incidental to this non-acoustic
component of the Navy's training and testing activities is not
reasonably likely to occur. This is due to the low speed at which the
SURTASS LFA sonar vessels test and train (10 to 12 knots (kt)) and the
suite of mitigation and monitoring efforts employed, including a three-
pronged monitoring effort that involves visual and passive acoustic
monitoring for marine mammals as well as use of the HF/M3 sonar (please
see the Proposed Mitigation section below for more detail), which has
been shown to be highly effective at detecting marine mammals. The Navy
has not requested authorization for take of marine mammals that might
occur incidental to vessel ship strike. In this document, NMFS analyzes
the potential effects on marine mammals from exposure to LFA and HF/M3
sonar, but also includes some additional analysis of the potential
impacts from vessel operations.
Overview of Potential Effects of Exposure to SURTASS LFA Sonar
Activities
The potential effects of sound from the proposed SURTASS LFA sonar
training and testing activities might include one or more of the
following: Behavioral changes, masking, non-auditory injury (i.e., gas
bubble formation/rectified diffusion), and noise-induced loss of
hearing sensitivity (more commonly called threshold shift). NMFS
discusses these potential effects in more detail below.
The effects of underwater noise on marine mammals are highly
variable, and one can categorize the effects as follows (Richardson et
al., 1995; Nowacek et al., 2007; Southall et al., 2007):
(1) The noise may be too weak to be heard at the location of the
animal (i.e., lower than the prevailing ambient noise level, the
hearing threshold of the animal at relevant frequencies, or both);
(2) The noise may be audible but not strong enough to elicit any
overt behavioral response;
(3) The noise may elicit behavioral reactions of variable
conspicuousness and relevance to the well-being of the animal. These
can range from temporary alert responses to active avoidance reactions
such as vacating an area at least until the noise event ceases, but
potentially for longer periods of time. Depending on the nature and
duration of these the disturbances, they could have effects on the
well-being or reproduction of the animals involved;
(4) Upon repeated exposure, a marine mammal may exhibit diminishing
responsiveness (habituation), disturbance effects may persist, or
disturbance effects could increase (sensitization, or becoming more
sensitive to exposure). Persistent disturbance and sensitization are
more likely with sounds that are highly variable in characteristics,
infrequent, and unpredictable in occurrence, and associated with
situations that the animal perceives as a threat. Marine mammals are
not likely to be exposed enough to SURTASS LFA sonar to exhibit
habituation or increased sensitization, due to the fact that SURTASS
LFA sonar is a mobile source
[[Page 7205]]
operating in open water, and animals are likely to move away and/or
would not be receiving pings in the way that small resident populations
would receive with a stationary source;
(5) Any anthropogenic (human-made) noise that is strong enough to
be heard has the potential to reduce the ability of a marine mammal to
hear natural sounds at similar frequencies (masking), including calls
from conspecifics, and underwater environmental sounds such as surf
noise;
(6) If mammals remain in an area because it is important for
feeding, breeding, or some other biologically important purpose even
though there is a chronic exposure to noise, it is possible that there
could be noise-induced physiological stress. This might in turn have
negative effects on the well-being or reproduction of the animals
involved; and
(7) Very strong sounds have the potential to cause temporary or
permanent reduction in hearing sensitivity, also known as threshold
shift. In terrestrial mammals and presumably marine mammals, received
sound levels must far exceed the animal's hearing threshold for there
to be any temporary threshold shift (TTS) in its hearing ability. For
transient sounds, the sound level necessary to cause TTS is inversely
related to the duration of the sound. Received sound levels must be
even higher for there to be the possibility of permanent hearing
impairment. In addition, intense acoustic events may cause trauma to
tissues associated with organs vital for hearing, sound production,
respiration and other functions. This trauma may include minor to
severe hemorrhage.
Direct Physiological Effects
Below we discuss the potential direct physiological effects of
exposure to SURTASS LFA sonar, which include threshold shift (permanent
and temporary) and acoustically mediated bubble growth.
Threshold Shift (Noise-Induced Loss of Hearing in Certain Frequencies)
When animals exhibit reduced hearing sensitivity within their
auditory range (i.e., sounds must be louder for an animal to detect
them) following exposure to a sufficiently intense sound, or a less
intense sound for a sufficient duration, it is referred to as a noise-
induced threshold shift (TS). An animal can experience a TTS and/or
permanent threshold shift (PTS). TTS can last from minutes or hours to
days (i.e., there is recovery back to baseline/pre-exposure levels),
can occur within a specific frequency range (i.e., an animal might only
have a temporary loss of hearing sensitivity within a limited frequency
band of its auditory range), and can be of varying amounts (for
example, an animal's hearing sensitivity might be reduced by only six
dB or reduced by 30 dB). PTS is permanent (i.e., there is incomplete
recovery back to baseline/pre-exposure levels), but also can occur in a
specific frequency range and amount as mentioned above for TTS.
The following physiological mechanisms are thought to play a role
in inducing auditory TS: Effects to sensory hair cells in the inner ear
that reduce their sensitivity; modification of the chemical environment
within the sensory cells; residual muscular activity in the middle ear;
displacement of certain inner ear membranes; increased blood flow; and
post-stimulatory reduction in both efferent and sensory neural output
(Southall et al., 2007). The amplitude, duration, frequency, temporal
pattern, and energy distribution of sound exposure all can affect the
amount of associated TS and the frequency range in which it occurs.
Generally, the amount of TS, and the time needed to recover from the
effect, increase as amplitude and duration of sound exposure increases.
Human non-impulsive noise exposure guidelines are based on the
assumption that exposures of equal energy (the same SEL) produce equal
amounts of hearing impairment regardless of how the sound energy is
distributed in time (NIOSH, 1998). Previous marine mammal TTS studies
have also generally supported this equal energy relationship (Southall
et al., 2007). However, some more recent studies concluded that for all
noise exposure situations the equal energy relationship may not be the
best indicator to predict TTS onset levels (Mooney et al., 2009a and
2009b; Kastak et al., 2007). These studies highlight the inherent
complexity of predicting TTS onset in marine mammals, as well as the
importance of considering exposure duration when assessing potential
impacts. Generally, with sound exposures of equal energy, those that
were quieter (lower sound pressure level (SPL)) with longer duration
were found to induce TTS onset at lower levels than those of louder
(higher SPL) and shorter duration. Less TS will occur from intermittent
sounds than from a continuous exposure with the same energy (some
recovery can occur between intermittent exposures) (Kryter et al.,
1966; Ward, 1997; Mooney et al., 2009a, 2009b; Finneran et al., 2010).
For example, one short but loud (higher SPL) sound exposure may induce
the same impairment as one longer but softer (lower SPL) sound, which
in turn may cause more impairment than a series of several intermittent
softer sounds with the same total energy (Ward, 1997). Additionally,
though TTS is temporary, very prolonged or repeated exposure to sound
strong enough to elicit TTS, or shorter-term exposure to sound levels
well above the TTS threshold can cause PTS, at least in terrestrial
mammals (Kryter, 1985; Lonsbury-Martin et al., 1987). However, in the
case of the proposed SURTASS LFA sonar activities, animals are not
expected to be exposed to levels high enough or durations long enough
to result in PTS due to the nature of the activities. The potential for
PTS becomes even more unlikely when mitigation measures are considered.
PTS is considered auditory injury (Southall et al., 2007). Irreparable
damage to the inner or outer cochlear hair cells may cause PTS;
however, other mechanisms are also involved, such as exceeding the
elastic limits of certain tissues and membranes in the middle and inner
ears and resultant changes in the chemical composition of the inner ear
fluids (Southall et al., 2007).
Although the published body of scientific literature contains
numerous theoretical studies and discussion papers on hearing
impairments that can occur with exposure to a loud sound, only a few
studies provide empirical information on the levels at which noise-
induced loss in hearing sensitivity occurs in nonhuman animals. The
NMFS 2018 Acoustic Technical Guidance, which was used in the assessment
of effects for this action, compiled, interpreted, and synthesized the
best available scientific information for noise-induced hearing effects
for marine mammals to derive updated thresholds for assessing the
impacts of noise on marine mammal hearing, as noted above. For
cetaceans, published data on the onset of TTS are limited to the
captive bottlenose dolphin, beluga, harbor porpoise, and Yangtze
finless porpoise (summarized in DoN, 2017). TTS studies involving
exposure to SURTASS LFA or other low-frequency sonar (below 1 kHz) have
never been conducted due to logistical difficulties of conducting
experiments with low frequency sound sources. However, there are TTS
measurements for exposures to other LF sources, such as seismic
airguns. Finneran et al. (2015) suggest that the potential for airguns
to cause hearing loss in dolphins is lower than previously predicted,
perhaps as a result of the low-frequency content of airgun impulses
compared to the high-
[[Page 7206]]
frequency hearing ability of dolphins. For pinnipeds in water,
measurements of TTS are limited to harbor seals, elephant seals, and
California sea lions (summarized in Finneran, 2015).
Marine mammal hearing plays a critical role in communication with
conspecifics and in interpretation of environmental cues for purposes
such as predator avoidance and prey capture. Depending on the degree
(elevation of threshold in dB), duration (i.e., recovery time), and
frequency range of TTS, and the context in which it is experienced, TTS
can have effects on marine mammals ranging from discountable to
serious, similar to those discussed in auditory masking, below.
Available data (of mid-frequency hearing specialists exposed to mid- or
high-frequency sounds; Southall et al., 2007) 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 SURTASS LFA source utilizes the 100-500 Hz frequency band, which
suggests that if TTS were to be induced it would be in a frequency band
somewhere between approximately 200 Hz and 1 kHz (but likely more in
the middle of that range), which is in the range of most communication
calls for mysticetes, some for pinnipeds, but below the range of most
communication calls for odontocetes. While there are some broadband
clicks in this range, most echolocation calls used by odontocetes for
foraging are also below this frequency. Also, a marine mammal may be
able to readily compensate for a brief, relatively small amount of TTS
in a non-critical frequency range that takes place during a time when
the animal is traveling through the open ocean, where ambient noise is
lower and there are not as many competing sounds present.
Alternatively, a larger amount and longer duration of TTS sustained
during a time when communication is critical for successful mother/calf
interactions could have more serious impacts if it were in the same
frequency band as the necessary vocalizations and of a severity that
impeded communication. The fact that animals exposed to high levels of
sound that would be expected to result in this physiological response
would also be expected to have behavioral responses of a comparatively
more severe or sustained nature is potentially more significant than
simple existence of a TTS. However, it is important to note that TTS
can result from longer exposures to sound at lower levels where a
behavioral response may not be elicited.
Depending on the degree and frequency range, the effects of PTS on
an animal could also range in severity, although PTS is considered
generally more serious than TTS because it is a permanent condition. Of
note, reduced hearing sensitivity as a simple function of aging has
been observed in marine mammals, as well as humans and other taxa
(Southall et al., 2007), so we can infer that strategies exist for
coping with this condition to some degree, though likely not without
some cost to the animal. There is no empirical evidence that exposure
to SURTASS LFA sonar can cause PTS in any marine mammals, especially
given the proximity to and duration that an animal would need to be
exposed; instead the possibility of PTS has been inferred from studies
of TTS on captive marine mammals.
As stated in the SURTASS DSEIS/SOEIS (section 4.5.2.1.3), modeling
results show that all hearing groups except LF cetaceans would need to
be within 22 feet (ft) (7 meters (m)) for an entire LFA transmission
(60 seconds) to potentially experience PTS. A LF cetacean would need to
be within 135 ft (41 m) for an entire LFA transmission to potentially
experience PTS. Based on the mitigation procedures used during SURTASS
LFA sonar activities, and the fact that animals reasonably can be
expected to move away from disturbances, the chances of this occurring
are negligible. This conclusion is supported by the fact that a marine
mammal would have to match its swim speed with that of the SURTASS LFA
sonar vessel while also remaining undetected by the HF/M3 mitigation
system as it moved through the 2,000-yard LFA Mitigation Zone, and
remain close to the source for a 60-second ping.
Acoustically Mediated Bubble Growth
One theoretical cause of injury to marine mammals is rectified
diffusion (Crum and Mao, 1996), the process of increasing the size of a
bubble by exposing it to a sound field. This process could be
facilitated if the environment in which the ensonified bubbles exist is
supersaturated with gas. Repetitive diving by marine mammals can cause
the blood and some tissues to accumulate gas to a greater degree than
is supported by the surrounding environmental pressure (Ridgway and
Howard, 1979). The deeper and longer dives of some marine mammals
(e.g., beaked whales) are theoretically predicted to induce greater
supersaturation (Houser et al., 2001b). A study of repetitive diving in
trained bottlenose dolphins found no increase in blood nitrogen levels
or formation of bubbles (Houser et al., 2009). If rectified diffusion
were possible in marine mammals exposed to high-level sound, conditions
of tissue supersaturation could theoretically speed the rate and
increase the size of bubble growth. Subsequent effects due to tissue
trauma and emboli would presumably mirror those observed in humans
suffering from decompression sickness.
It is unlikely that the short duration of the SURTASS LFA sonar
pings would be long enough to drive bubble growth to any substantial
size, if such a phenomenon occurs. However, an alternative but related
hypothesis has also been suggested; stable bubbles could be
destabilized by high-level sound exposures such that bubble growth then
occurs through static diffusion of gas out of the tissues. In such a
scenario the marine mammal would need to be in a gas-supersaturated
state for a long enough period of time for bubbles to become a
problematic size. Research with ex vivo supersaturated bovine tissues
suggests that, for a 37 kHz signal, a sound exposure of approximately
215 dB re 1[micro]Pa would be required before microbubbles became
destabilized and grew (Crum et al., 2005). Furthermore, tissues in the
study were supersaturated by exposing them to pressures of 400-700
kiloPascals for periods of hours and then releasing them to ambient
pressures. Assuming the equilibration of gases with the tissues
occurred when the tissues were exposed to high pressures, levels of
supersaturation in the tissues could have been as high as 400-700
percent. These levels of tissue supersaturation are substantially
higher than model predictions for marine mammals (Houser et al., 2001;
Saunders et al., 2008). Both the degree of supersaturation and exposure
levels observed to cause microbubble destabilization are unlikely to
occur, either alone or in concert.
Yet another hypothesis (decompression sickness) speculates that
rapid ascent to the surface following exposure to a startling sound
might produce tissue gas saturation sufficient for the evolution of
nitrogen bubbles (Jepson et al., 2003; Fernandez et al., 2005;
Fernandez et al., 2012). In this scenario, the rate of ascent would
need to be sufficiently rapid to compromise behavioral or physiological
protections against nitrogen bubble formation. Alternatively, Tyack et
al. (2006) studied the deep diving behavior of beaked whales and
concluded that: ``Using current models of breath-hold diving, we infer
that their natural diving behavior is inconsistent with known problems
of acute nitrogen
[[Page 7207]]
supersaturation and embolism.'' Collectively, these hypotheses
(rectified diffusion and decompression sickness) can be referred to as
``hypotheses of acoustically-mediated bubble growth.''
Although theoretical predictions suggest the possibility for
acoustically mediated bubble growth, there is considerable disagreement
among scientists as to its likelihood (Piantadosi and Thalmann, 2004;
Evans and Miller, 2003; Cox et al., 2006; Rommel et al., 2006). Crum
and Mao (1996) hypothesized that received levels would have to exceed
190 dB in order for there to be the possibility of significant bubble
growth due to supersaturation of gases in the blood (i.e., rectified
diffusion). Work conducted by Crum et al. (2005) demonstrated the
possibility of rectified diffusion for short duration signals, but at
exposure levels and tissue saturation levels that are highly improbable
to occur in diving marine mammals. Nowacek et al. (2007) and Southall
et al. (2007) reviewed potential types of non-auditory injury to marine
mammals from active sonar transmissions, including acoustically
mediated bubble growth within tissues from supersaturated dissolved
nitrogen gas. Detailed descriptions and information on these types of
non-auditory impacts were provided in previous documentation for
SURTASS LFA sonar (DoN, 2007, 2012, 2017), and no new data have emerged
to contradict any of the assumptions or conclusions in previous LFA
documentation, especially the conclusion that SURTASS LFA sonar
transmissions are not expected to cause gas bubble formation or
strandings. Although it has been argued that traumas from some beaked
whale strandings are consistent with gas emboli and bubble-induced
tissue separations (Jepson et al., 2003), there is no conclusive
evidence of this (Rommel et al., 2006). However, Jepson et al. (2003,
2005) and Fernandez et al. (2004, 2005, 2012) concluded that in vivo
bubble formation, which may be exacerbated by deep, long-duration,
repetitive dives, may explain why beaked whales appear to be
particularly vulnerable to MF and HF active sonar exposures. This has
not been demonstrated for LF sonar exposures, such as SURTASS LFA
sonar.
In 2009, Hooker et al. tested two mathematical models to predict
blood and tissue tension N2 (PN2) using field data from
three beaked whale species: Northern bottlenose whales, Cuvier's beaked
whales, and Blainville's beaked whales. The researchers aimed to
determine if physiology (body mass, diving lung volume, and dive
response) or dive behavior (dive depth and duration, changes in ascent
rate, and diel behavior) would lead to differences in PN2
levels and thereby decompression sickness risk between species.
In their study, they compared results for previously published time
depth recorder data (Hooker and Baird, 1999; Baird et al., 2006, 2008)
from Cuvier's beaked whale, Blainville's beaked whale, and northern
bottlenose whale. They reported that diving lung volume and extent of
the dive response had a large effect on end-dive PN2. Also,
results showed that dive profiles had a larger influence on end-dive
PN2 than body mass differences between species. Despite diel
changes (i.e., variation that occurs regularly every day or most days)
in dive behavior, PN2 levels showed no consistent trend.
Model output suggested that all three species live with tissue
PN2 levels that would cause a significant proportion of
decompression sickness cases in terrestrial mammals. The authors
concluded that the dive behavior of Cuvier's beaked whale was different
from both Blainville's beaked whale and northern bottlenose whale,
resulting in higher predicted tissue and blood N2 levels (Hooker et
al., 2009) and suggesting that the prevalence of Cuvier's beaked whale
strandings after naval sonar exercises could be explained by either a
higher abundance of this species in the affected areas, or by possible
species differences in behavior and/or physiology related to MF active
sonar (Hooker et al., 2009).
Bernaldo de Quiros et al. (2012) showed that, among evaluated
stranded whales, deep diving species of whales had higher abundances of
gas bubbles compared to shallow diving species. Kvadsheim et al. (2012)
estimated blood and tissue PN2 levels in species
representing shallow, intermediate, deep diving cetaceans following
behavioral responses to sonar and their comparisons found that deep
diving species had higher end-dive blood and tissue N2
levels, indicating a higher risk of developing gas bubble emboli
compared with shallow diving species. Fahlmann et al. (2014) evaluated
dive data recorded from sperm, killer, long-finned pilot, Blainville's
beaked and Cuvier's beaked whales before and during exposure to low (1-
2 kHz) and mid (2-7 kHz) frequency active sonar in an attempt to
determine if either differences in dive behavior or physiological
responses to sonar are plausible risk factors for bubble formation.
Note that SURTASS LFA sonar is transmitted between 100-500 Hz, which is
well below the low frequency sonar in these studies. The authors
suggested that CO2 may initiate bubble formation and growth,
while elevated levels of N2 may be important for continued
bubble growth. The authors also suggest that if CO2 plays an
important role in bubble formation, a cetacean escaping a sound source
may experience increased metabolic rate, CO2 production, and
alteration in cardiac output, which could increase risk of gas bubble
emboli. However, as discussed in Kvadsheim et al. (2012), the actual
observed behavioral responses to sonar from the species in their study
(sperm, killer, long-finned pilot, Blainville's beaked, and Cuvier's
beaked whales) did not imply any significantly increased risk of
decompression sickness due to high levels of N2. Therefore,
further information is needed to understand the relationship between
exposure to stimuli, behavioral response (discussed in more detail
below), elevated N2 levels, and gas bubble emboli in marine
mammals. The hypotheses for gas bubble formation related to beaked
whale strandings is that beaked whales potentially have strong
avoidance responses to MF active sonars because they sound similar to
their main predator, the killer whale (Cox et al., 2006; Southall et
al., 2007; Zimmer and Tyack, 2007; Baird et al., 2008; Hooker et al.,
2009). Further investigation is needed to assess the potential validity
of these hypotheses. However, because SURTASS LFA sonar transmissions
are lower in frequency (less than 500 Hz) and dissimilar in
characteristics from those of marine mammal predators, the SURTASS LFA
sonar transmissions are not expected to cause gas bubble formation or
beaked whale strandings.
To summarize, there are few data related to the potential for
strong, anthropogenic underwater sounds to cause non-auditory physical
effects in marine mammals. Such effects, if they occur at all, would
presumably be limited to situations where marine mammals were exposed
to high powered sounds at close range over a prolonged period of time.
The available data do not allow identification of a specific exposure
level above which non-auditory effects can be expected (Southall et
al., 2007) or any meaningful quantitative predictions of the numbers
(if any) of marine mammals that might be affected in those ways.
However, as noted above, non-auditory physical effects are not likely
to result from the use of SURTASS LFA sonar because of the required
mitigation and unlikelihood of marine mammals being exposed to high
powered sounds at close range.
[[Page 7208]]
Acoustic Masking
Marine mammals use acoustic signals for a variety of purposes,
which differ among species, but include communication between
individuals, navigation, foraging, reproduction, and learning about
their environment (Erbe and Farmer, 2000; Tyack, 2000). Masking, or
auditory interference, generally occurs when other sounds in the
environment are of a similar frequency and are louder than auditory
signals an animal is trying to receive. Masking is a phenomenon that
affects animals trying to receive acoustic information about their
environment, including sounds from other members of their species,
predators, prey, and sounds that allow them to orient in their
environment. Masking these acoustic signals can disrupt the behavior of
individual animals, groups of animals, or, when over large spatial and
temporal scales, entire populations.
The extent of the masking interference depends on the spectral,
temporal, and spatial relationships between the signals an animal is
trying to receive and the masking noise, in addition to other factors.
In humans, significant masking of tonal signals occurs as a result of
exposure to noise in a narrow band of similar frequencies. As the sound
level increases, the detection of frequencies above those of the
masking stimulus decreases. This principle is expected to apply to
marine mammals as well because of common biomechanical cochlear
properties across taxa.
Richardson et al. (1995b) argued that the maximum radius of
influence of an industrial noise (including broadband low-frequency
sound transmission) on a marine mammal is the distance from the source
to the point at which the noise can barely be heard. This range is
determined by either the hearing sensitivity of the animal or the
background noise level present. Industrial masking has the potential to
affect some species' ability to detect communication calls and natural
sounds (i.e., surf noise, prey noise, etc.) (Richardson et al., 1995).
Erbe et al. (2016) reviewed the current state of understanding of
masking in marine mammals, including anti-masking strategies for both
receivers and senders. When a signal and noise are received from
different directions, a receiver with directional hearing can reduce
the masking impact. This is known as spatial release from masking, and
this ability has been found in dolphins, killer whales and harbor
seals. Given the hearing abilities of marine mammals, it is likely that
most, if not all, species have this ability to some extent.
The echolocation calls of toothed whales are subject to masking by
high-frequency sound. Human data indicate that low-frequency sounds can
mask high-frequency sounds (i.e., upward masking). Studies on captive
odontocetes by Au et al. (1974, 1985, and 1993) indicate that some
species may use various processes to reduce masking effects (e.g.,
adjustments in echolocation call intensity or frequency as a function
of background noise conditions). There is also evidence that the
directional hearing abilities of odontocetes are useful in reducing
masking at the higher frequencies these cetaceans use to echolocate,
but not at the low-to-moderate frequencies they use to communicate
(Zaitseva et al., 1980). A study by Nachtigall and Supin (2008) showed
that false killer whales adjust their hearing to compensate for ambient
sounds and the intensity of returning echolocation signals. Holt et al.
(2009) measured killer whale call source levels and background noise
levels in the one to 40 kHz band and reported that the whales increased
their call source levels by one dB SPL for every one dB SPL increase in
background noise level. Similarly, another study on St. Lawrence River
belugas reported a similar rate of increase in vocalization activity in
response to passing vessels (Scheifele et al., 2005).
Parks et al. (2007) provided evidence of behavioral changes in the
acoustic behaviors of the endangered North Atlantic right whale, and
the South Atlantic right whale, and suggested that these were
correlated to increased underwater noise levels. The study indicated
that right whales might shift the frequency band of their calls to
compensate for increased in-band background noise. The significance of
their result is the indication of potential species-wide behavioral
change in response to gradual, chronic increases in underwater ambient
noise. Di Iorio and Clark (2010) showed that blue whale calling rates
vary in association with seismic sparker survey activity, with whales
calling more on days with survey than on days without surveys. They
suggested that the whales called more during seismic survey periods as
a way to compensate for the elevated noise conditions.
Risch et al. (2012) documented reductions in humpback whale
vocalizations in the Stellwagen Bank National Marine Sanctuary
concurrent with transmissions of the Ocean Acoustic Waveguide Remote
Sensing (OAWRS) low-frequency fish sensor system at distances of 200 km
(124 mi) from the source. The recorded OAWRS produced a series of
frequency-modulated pulses and the signal received levels ranged from
88 to 110 dB re: 1 [mu]Pa (Risch et al., 2012). The authors
hypothesized that individuals did not leave the area but instead ceased
singing and noted that the duration and frequency range of the OAWRS
signals (a novel sound to the whales) were similar to those of natural
humpback whale song components used during mating (Risch et al., 2012).
Thus, the novelty of the sound to humpback whales in the study area
provided a compelling contextual probability for the observed effects
(Risch et al., 2012). However, the authors did not state or imply that
these changes had long-term effects on individual animals or
populations (Risch et al., 2012). Gong et al., (2014) assessed the
effects of the OAWRS transmissions on calling rates on Georges Bank and
determined constant vocalization rates of humpback whales, with a
reduction occurring before the OAWRS system began transmitting. Risch
et al. (2014) pointed out that the results of Risch et al. (2012) and
Gong et al. (2014) are not contradictory, but rather highlight the
principal point of their original paper that behavioral responses
depend on many factors, including range to source, RL above background
noise level, novelty of signal, and differences in behavioral state.
Redundancy and context can also facilitate detection of weak
signals. These phenomena may help marine mammals detect weak sounds in
the presence of natural or manmade noise. Most masking studies in
marine mammals present the test signal and the masking noise from the
same direction. The sound localization abilities of marine mammals
suggest that, if signal and noise come from different directions,
masking would not be as severe as some masking studies might suggest
(Richardson et al., 1995). The dominant background noise may be highly
directional if it comes from a particular anthropogenic source such as
a ship or industrial site. Directional hearing may significantly reduce
the masking effects of these sounds by improving the effective signal-
to-noise ratio.
As mentioned previously, the hearing ranges of mysticetes overlap
with the frequencies of the SURTASS LFA sonar sources. The closer the
characteristics of the masking signal to the signal of interest, the
more likely masking is to occur. The Navy provided an analysis of
marine mammal hearing and masking in Subchapter 4.5.2.1.3 of the DSEIS/
[[Page 7209]]
SOEIS, and the masking effects of the SURTASS LFA sonar signal are
expected to be limited for a number of reasons. First, the frequency
range (bandwidth) of the system is limited to approximately 30 Hz, and
the instantaneous bandwidth at any given time of the signal is small,
on the order of 10 Hz. Second, the average duty cycle is always less
than 20 percent and, based on past SURTASS LFA sonar operational
parameters (2003 to 2018), is normally 7.5 to 10 percent. Third, given
the average maximum pulse length (60 sec), and the fact that the
signals vary and do not remain at a single frequency for more than 10
sec, SURTASS LFA sonar is not likely to cause significant masking. In
other words, the LFA sonar transmissions are coherent, narrow bandwidth
signals of six to 100 sec in length followed by a quiet period of six
to 15 minutes. Therefore, the effect of masking will be limited because
animals that use this frequency range typically use broader bandwidth
signals. As a result, the chances of an LFA sonar sound actually
overlapping whale calls at levels that would interfere with their
detection and recognition will be extremely low.
Impaired Communication
In addition to making it more difficult for animals to perceive
acoustic cues in their environment, anthropogenic sound presents
separate challenges for animals that are vocalizing. When they
vocalize, animals are aware of environmental conditions that affect the
``active space'' of their vocalizations, which is the maximum area
within which their vocalizations can be detected before they drop to
the level of ambient noise (Brenowitz, 2004; Brumm et al., 2004; Lohr
et al., 2003). Animals are also aware of environmental conditions that
affect whether listeners can discriminate and recognize their
vocalizations apart from other sounds, which is more important than
simply detecting that a vocalization is occurring (Brenowitz, 1982;
Brumm et al., 2004; Dooling, 2004, Marten and Marler, 1977; Patricelli
et al., 2006). Most species that vocalize are able to adapt by
adjusting their vocalizations to increase the signal-to-noise ratio,
active space, and recognizability/distinguishability of their
vocalizations in the face of temporary changes in background noise
(Brumm et al., 2004; Patricelli et al., 2006). Vocalizing animals can
make adjustments to vocalization characteristics such as the frequency
structure, amplitude, temporal structure and temporal delivery.
Many animals will combine several of these strategies to compensate
for high levels of background noise. Anthropogenic sounds that reduce
the signal-to-noise ratio of animal vocalizations, increase the masked
auditory thresholds of animals listening for such vocalizations, or
reduce the active space of an animal's vocalizations, impairing
communications between animals. Most animals that vocalize have evolved
strategies to compensate for the effects of short-term or temporary
increases in background or ambient noise on their songs or calls.
Although the fitness consequences of these vocal adjustments are not
directly known in all instances, like most other trade-offs animals
must make, some of these strategies probably come at a cost (Patricelli
et al., 2006). Shifting songs and calls to higher frequencies may also
impose energetic costs (Lambrechts, 1996). For example in birds,
vocalizing more loudly in noisy environments may have energetic costs
that decrease the net benefits of vocal adjustment and alter a bird's
energy budget (Brumm, 2004; Wood and Yezerinac, 2006).
Stress Responses
Classic stress responses begin when an animal's central nervous
system perceives a potential threat to its homeostasis. That perception
triggers stress responses regardless of whether a stimulus actually
threatens the animal; the mere perception of a threat is sometimes
sufficient to trigger a stress response (Moberg, 2000; Sapolsky et al.,
2005; Seyle, 1950). Once an animal's central nervous system perceives a
threat, it mounts a biological response or defense that consists of a
combination of the four general biological defense responses:
Behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses.
According to Moberg (2000), in the case of many stressors, an
animal's first and most economical (in terms of biotic costs) response
is behavioral avoidance of the potential stressor or avoidance of
continued exposure to a stressor. An animal's second line of defense to
stressors involves the sympathetic part of the autonomic nervous system
and the classical ``fight or flight'' response which includes the
cardiovascular system, the gastrointestinal system, the exocrine
glands, and the adrenal medulla to produce changes in heart rate, blood
pressure, and gastrointestinal activity that humans commonly associate
with ``stress.'' These responses have a relatively short duration and
may or may not have significant long-term effect on an animal's
welfare.
An animal's third line of defense to stressors involves its
neuroendocrine or sympathetic nervous systems; the system that has
received the most study has been the hypothalmus-pituitary-adrenal
system (also known as the HPA axis in mammals or the hypothalamus-
pituitary-interrenal axis in fish and some reptiles). Unlike stress
responses associated with the autonomic nervous system, virtually all
neuro-endocrine functions that are affected by stress--including immune
competence, reproduction, metabolism, and behavior--are regulated by
pituitary hormones. Stress-induced changes in the secretion of
pituitary hormones have been implicated in failed reproduction (Moberg,
1987; Rivier and Rivest, 1991), altered metabolism (Elasser et al.,
2000), reduced immune competence (Blecha, 2000), and behavioral
disturbance (Moberg, 1987; Blecha, 2000). Increases in the circulation
of glucocorticosteroids (cortisol, corticosterone, and aldosterone in
marine mammals; see Romano et al., 2004) have been equated with stress
for many years.
The primary distinction between stress, which is adaptive and does
not normally place an animal at risk, and distress is the biotic cost
of the response. During a stress response, an animal uses glycogen
stores that can be quickly replenished once the stress is alleviated.
In such circumstances, the cost of the stress response would not pose a
risk to the animal's welfare. However, when an animal does not have
sufficient energy reserves to satisfy the energetic costs of a stress
response, energy resources must be diverted from other biotic
functions, which impair those functions. For example, when a stress
response diverts energy away from growth in young animals, those
animals may experience stunted growth. When a stress response diverts
energy from a fetus, an animal's reproductive success and fitness will
suffer. In these cases, the animals will have entered a pre-
pathological or pathological state which is called distress (Seyle,
1950) or allostatic loading (McEwen and Wingfield, 2003). This
pathological state will last until the animal replenishes its biotic
reserves sufficient to restore normal function. Note that these
examples involve a long-term (days or weeks) stress response exposure
to stimuli.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses have also been documented
fairly well through controlled experiments; because this physiology
exists in every vertebrate that has been studied, it is not surprising
that stress
[[Page 7210]]
responses and their costs have been documented in both laboratory and
free-living animals (for examples see, Holberton et al., 1996; Hood et
al., 1998; Jessop et al., 2003; Krausman et al., 2004; Lankford et al.,
2005; Thompson and Hamer, 2000).
There is limited information on the physiological responses of
marine mammals to anthropogenic sound exposure, as most observations
have been limited to short-term behavioral responses, which included
cessation of feeding, resting, or social interactions. Information has
been collected on the physiological responses of marine mammals to
anthropogenic sounds (Fair and Becker, 2000; Romano et al., 2002;
Wright et al., 2008), and various efforts have been undertaken to
investigate the impact from vessels including whale watching vessels as
well as general vessel traffic noise (Bain, 2002; Erbe, 2002; Noren et
al., 2009; Williams et al., 2006, 2009, 2014a, 2014b; Read et al.,
2014; Rolland et al., 2012; Pirotta et al., 2015). This body of
research for the most part has investigated impacts associated with the
presence of chronic stressors (e.g., whale watch vessels), which differ
significantly from the proposed Navy SURTASS LFA sonar activities. For
example, in the analysis of energy costs to killer whales, Williams et
al. (2009) suggested that whale-watching in Canada's Johnstone Strait
resulted in lost feeding opportunities due to vessel disturbance, which
could carry higher costs than other measures of behavioral change might
suggest. Ayres et al. (2012) reported on research in the Salish Sea
(state of Washington) involving the measurement of southern resident
killer whale fecal hormones to assess two potential threats to the
species recovery: Lack of prey (salmon) and impacts to behavior from
vessel traffic. The authors suggested that the lack of prey
overshadowed any population-level physiological impacts on southern
resident killer whales from vessel traffic. Rolland et al. (2012) found
that noise reduction from reduced ship traffic in the Bay of Fundy was
associated with decreased stress in North Atlantic right whales. In a
conceptual model developed by the Population Consequences of Acoustic
Disturbance (PCAD) working group, serum hormones were identified as
possible indicators of behavioral effects that are translated into
altered rates of reproduction and mortality (NRC, 2005). The Office of
Naval Research hosted a workshop (Effects of Stress on Marine Mammals
Exposed to Sound) in 2009 that focused on this very topic (ONR, 2009).
Ultimately, the PCAD working group issued a report (Cochrem, 2014) that
summarized information compiled from 239 papers or book chapters
relating to stress in marine mammals and concluded that stress
responses can last from minutes to hours and, while we typically focus
on adverse stress responses, stress response is part of a natural
process to help animals adjust to changes in their environment and can
also be either neutral or beneficial. Of note, work published by the
National Academies of Sciences, Engineering and Medicine built upon
previous reports to assess current methodologies used for evaluating
cumulative effects and identified new approaches that could improve
these assessments focusing on ways to quantify exposure-related changes
in behavior, health, or body condition of individual marine mammals
(National Academies, 2017).
Despite the lack of robust information on stress responses for
marine mammals exposed to anthropogenic sounds, studies of other marine
and terrestrial animals lead us to expect some marine mammals to
experience physiological stress responses and, perhaps, physiological
responses that would be classified as distress upon exposure to low-
frequency sounds. For example, Jansen (1998) reported on the
relationship between acoustic exposures and physiological responses
that are indicative of stress responses in humans (e.g., elevated
respiration and increased heart rates). Jones (1998) reported on
reductions in human performance when faced with acute, repetitive
exposures to acoustic disturbance. Trimper et al. (1998) reported on
the physiological stress responses of osprey to low-level aircraft
noise while Krausman et al. (2004) reported on the auditory and
physiology stress responses of endangered Sonoran pronghorn to military
overflights. Smith et al. (2004a, 2004b) identified noise-induced
physiological transient stress responses in hearing-specialist fish
(i.e., goldfish) that accompanied short- and long-term hearing losses.
Welch and Welch (1970) reported physiological and behavioral stress
responses that accompanied damage to the inner ears of fish and several
mammals.
Hearing is one of the primary senses marine mammals use to gather
information about their environment and communicate with conspecifics.
Although empirical information on the relationship between sensory
impairment (TTS, PTS, and acoustic masking) and stress in marine
mammals remains limited, it is reasonable to assume that reducing an
animal's ability to gather information about its environment and
communicate with conspecifics could induce stress in animals that use
hearing as their primary sensory mechanism. We also assume that
acoustic exposures sufficient to trigger onset of a threshold shift
(PTS or TTS) would be accompanied by physiological stress responses,
because terrestrial animals exhibit those responses under similar
conditions (NRC, 2003). More importantly, due to the effect of noise
and the need to effectively gather acoustic information and respond,
marine mammals might experience stress responses at received levels
lower than those necessary to trigger onset of TTS. Based on empirical
studies of the time required to recover from stress responses (Moberg,
2000), NMFS also assumes that stress responses could persist beyond the
time interval required for animals to recover from TTS and might result
in pathological and pre-pathological states that would be as
significant as behavioral responses associated with TTS. Much more
research is needed to begin to understand the potential for
physiological stress in marine mammals. As discussed in the Behavioral
Response/Disturbance section below, the existing data suggest a
variable response that depends on the characteristics of the received
signal and prior experience with the received signal. However, NMFS
anticipates that the nature of SURTASS LFA sonar training and testing
activities, where a small number of vessels operate LFA sonar for
relatively short durations in open ocean environments, in combination
with many of the same factors discussed above related to masking, will
limit the potential for stress responses due to SURTASS LFA sonar
training and testing activities. These factors include the fact that
continuous-frequency waveforms have durations of no longer than 10
seconds; frequency-modulated waveforms have limited bandwidths (30 Hz);
and when LFA sonar is transmitting, the source is active only 7.5 to 10
percent of the time, with a maximum 20 percent duty cycle, which means
that for 90 to 92.5 percent of the time, there is no potential for
masking.
Behavioral Response/Disturbance
Southall et al. (2007) reviewed the available literature on marine
mammal hearing and physiological and behavioral responses to human-made
sound with the goal of proposing exposure criteria for certain effects.
This peer-reviewed compilation of literature is very valuable, though
Southall et al. (2007) note that not all data are equal:
[[Page 7211]]
Some have poor statistical power, insufficient controls, and/or limited
information on received levels, background noise, and other potentially
important contextual variables. Such data were reviewed and sometimes
used for qualitative illustration, but no quantitative criteria were
recommended for behavioral responses. All of the studies considered,
however, contain an estimate of the received sound level when the
animal exhibited the indicated response.
In the Southall et al. (2007) publication, for the purposes of
analyzing responses of marine mammals to anthropogenic sound and
developing criteria, the authors differentiate between single pulse
sounds, multiple pulse sounds, and non-pulse sounds. LFA sonar is
considered a non-pulse sound. Southall et al. (2007) summarizes the
studies associated with low-frequency, mid-frequency, and high-
frequency cetacean and pinniped responses to non-pulse sounds, based
strictly on received level, in Appendix C of their article
(incorporated by reference and summarized in the following paragraphs).
The studies that address responses of low-frequency cetaceans to
non-pulse sounds include data gathered in the field and related to
several types of sound sources, including: Vessel noise, drilling and
machinery playback, low-frequency M-sequences (sine wave with multiple
phase reversals) playback, tactical low-frequency active sonar
playback, drill ships, Acoustic Thermometry of Ocean Climate (ATOC)
source, and non-pulse playbacks. These studies generally indicate no
(or very limited) responses to received levels in the 90 to 120 dB re:
1 [micro]Pa range and an increasing likelihood of avoidance and other
behavioral effects in the 120 to 160 dB re: 1 [micro]Pa range. As
mentioned earlier, though, contextual variables play a very important
role in the reported responses, and the severity of effects are not
necessarily linear when compared to a received level. Also, few of the
laboratory or field datasets had common conditions, behavioral
contexts, or sound sources, so it is not surprising that responses
differ.
The studies that address responses of mid-frequency cetaceans to
non-pulse sounds include data gathered both in the field and the
laboratory and related to several different sound sources including:
Pingers, drilling playbacks, ship and ice-breaking noise, vessel noise,
Acoustic Harassment Devices (AHDs), Acoustic Deterrent Devices (ADDs),
MF active sonar, and non-pulse bands and tones. Southall et al. (2007)
were unable to come to a clear conclusion regarding the results of
these studies. In some cases, animals in the field showed significant
responses to received levels between 90 and 120 dB re: 1 [micro]Pa,
while in other cases these responses were not seen in the 120 to 150 dB
re: 1 [micro]Pa range. The disparity in results was likely due to
contextual variation and the differences between the results in the
field and laboratory data (animals typically responded at lower levels
in the field).
The studies that address responses of high-frequency cetaceans to
non-pulse sounds include data gathered both in the field and the
laboratory and related to several different sound sources including:
Pingers, AHDs, and various laboratory non-pulse sounds. All of these
data were collected from harbor porpoises. Southall et al. (2007)
concluded that the existing data indicate that harbor porpoises are
likely sensitive to a wide range of anthropogenic sounds at low
received levels (approximately 90-120 dB re: 1 [micro]Pa), at least for
initial exposures. All recorded exposures above 140 dB re: 1 [micro]Pa
induced profound and sustained avoidance behavior in wild harbor
porpoises (Southall et al., 2007). Rapid habituation was noted in some
but not all studies. There are no data to indicate whether other high-
frequency cetaceans are as sensitive to anthropogenic sound as harbor
porpoises.
The studies that address the responses of pinnipeds in water to
non-pulse sounds include data gathered both in the field and the
laboratory and related to several different sound sources including:
AHDs, ATOC, various non-pulse sounds used in underwater data
communication, underwater drilling, and construction noise. Few studies
exist with enough information to include them in this analysis. The
limited data suggest that exposure to non-pulse sounds between 90 and
140 dB re: 1 [micro]Pa generally do not result in strong behavioral
responses of pinnipeds in water, but no data exist at higher received
levels.
Behavioral responses to sound are highly variable and context-
specific. Many different variables can influence an animal's perception
of, as well as the nature and magnitude of response to, an acoustic
event. An animal's prior experience with a sound or sound source
affects whether it is less likely (habituation) or more likely
(sensitization) to respond to certain sounds in the future. Animals can
also be innately predisposed to respond to certain sounds in certain
ways (Southall et al., 2007). Related to the sound itself, the
perceived nearness of the sound, bearing of the sound (approaching vs.
retreating), similarity of the sound to biologically relevant sounds in
the animal's environment (i.e., calls of predators, prey, or
conspecifics), and familiarity of the sound may affect the way an
animal responds to the sound (Southall et al., 2007; DeRuiter et al.,
2013). Individuals of different age, gender, reproductive status, etc.
among most populations will have variable hearing capabilities, and
differing behavioral sensitivities to sounds that will be affected by
prior conditioning, experience, and current activities of those
individuals. Often, specific acoustic features of the sound and
contextual variables (i.e., proximity, duration, or recurrence of the
sound or the current behavior that the marine mammal is engaged in or
its prior experience), as well as entirely separate factors such as the
physical presence of a nearby vessel, may be more relevant to the
animal's response than the received level alone. For example, Goldbogen
et al. (2013) demonstrated that individual behavioral state was
critically important in determining response of blue whales to sonar,
noting that individuals engaged in deep (>50 m) feeding behavior had
greater dive responses than those in shallow feeding or non-feeding
conditions. Some blue whales in the Goldbogen et al. (2013) study that
were engaged in shallow feeding behavior demonstrated no clear changes
in diving or movement even when RLs were high (~160 dB re 1[micro]Pa)
for exposures to 3-4 kHz sonar signals, while others showed a clear
response at exposures at lower RLs of sonar and pseudorandom noise.
Studies by DeRuiter et al. (2012) indicate that variability of
responses to acoustic stimuli depends not only on the species receiving
the sound and the sound source, but also on the social, behavioral, or
environmental contexts of exposure. Another study by DeRuiter et al.
(2013) examined behavioral responses of Cuvier's beaked whales to MF
sonar and found that whales responded strongly at low received levels
(RL of 89-127 dB re 1[micro]Pa) by ceasing normal fluking and
echolocation, swimming rapidly away, and extending both dive duration
and subsequent non-foraging intervals when the sound source was 3.4-9.5
km away. Importantly, this study also showed that whales exposed to a
similar range of RLs (78-106 dB re 1[micro]Pa) from distant sonar
exercises (118 km away) did not elicit such responses, suggesting that
context (here, in the form of distance) may moderate reactions. In a
review of research conducted, including 370 published papers, Gomez et
al. (2016)
[[Page 7212]]
demonstrated that more severe behavioral responses were not
consistently associated with higher RL, but that the type of source
transmitting the acoustic energy was a key factor, highlighting the
importance of context of exposure in impact analysis.
Ellison et al. (2012) outlined an approach to assessing the effects
of sound on marine mammals that incorporates contextual-based factors.
The authors recommend considering not just the received level of sound,
but also the activity the animal is engaged in at the time the sound is
received, the nature and novelty of the sound (i.e., is this a new
sound from the animal's perspective), and the distance between the
sound source and the animal. They submit that this ``exposure
context,'' as it is termed, greatly influences the type of behavioral
response exhibited by the animal. This sort of contextual information
is challenging to predict with accuracy for ongoing activities that
occur over large spatial and temporal expanses. While contextual
elements of this sort are typically not included in calculations to
quantify take estimates of marine mammals, they are often considered
qualitatively in the analysis of the likely consequences of sound
exposure, where supporting information is available.
Friedlaender et al. (2016) provided the first integration of direct
measures of prey distribution and density variables incorporated into
across-individual analyses of behavior responses of blue whales to
sonar, and demonstrated a 5-fold increase in the ability to quantify
variability in blue whale diving behavior. These results illustrate
that responses evaluated without such measurements for foraging animals
may be misleading, which again illustrates the context-dependent nature
of the probability of response.
Exposure of marine mammals to sound sources can result in, but is
not limited to, no response or any of the following observable
responses: Increased alertness; orientation or attraction to a sound
source; vocal modifications; cessation of feeding; cessation of social
interaction; alteration of movement or diving behavior; avoidance;
habitat abandonment (temporary or permanent); and, in severe cases,
panic, flight, stampede, or stranding, potentially resulting in death
(Southall et al., 2007). A review of marine mammal responses to
anthropogenic sound was first conducted by Richardson (1995). More
recent reviews (Nowacek et al., 2007; DeRuiter et al., 2012 and 2013;
Ellison et al., 2012) addressed studies conducted since 1995 and
focused on observations where the received sound level of the exposed
marine mammal(s) was known or could be estimated. In a review of
experimental field studies to measure behavioral responses of cetaceans
to sonar, Southall et al. (2016) states that results demonstrate that
some individuals of different species display clear yet varied
responses, some of which have negative implications, while others
appear to tolerate high levels, and that responses may not be fully
predictable with simple acoustic exposure metrics (e.g., received sound
level). Rather, the authors state that differences among species and
individuals along with contextual aspects of exposure (e.g., behavioral
state) appear to affect response probability. The following subsections
provide examples of behavioral responses that provide an idea of the
variability in behavioral responses that would be expected given the
different sensitivities of marine mammal species to sound and the wide
range of potential acoustic sources to which a marine mammal may be
exposed. Predictions about the types of behavioral responses that could
occur for a given sound exposure should be determined from the
literature that is available for each species or extrapolated from
closely related species when no information exists, along with
contextual factors.
Alteration of Diving or Movement
Changes in dive behavior can vary widely. They may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive. Variations in
dive behavior may reflect interruptions in biologically significant
activities (e.g., foraging) or they may be of little biological
significance. Variations in dive behavior may also expose an animal to
potentially harmful conditions (e.g., increasing the chance of ship-
strike) or may serve as an avoidance response that enhances
survivorship. The impact of a variation in diving resulting from an
acoustic exposure depends on what the animal is doing at the time of
the exposure and the type and magnitude of the response.
Nowacek et al. (2004) reported disruptions of dive behaviors in
foraging North Atlantic right whales when exposed to an alerting
stimulus, which they noted could lead to an increased likelihood of
ship strike. However, the whales did not respond to playbacks of either
right whale social sounds or vessel noise, highlighting the importance
of the sound characteristics in producing a behavioral reaction.
Conversely, Indo-Pacific humpback dolphins have been observed to dive
for longer periods of time in areas where vessels were present and/or
approaching (Ng and Leung, 2003). In both of these studies, the
influence of the sound exposure cannot be decoupled from the physical
presence of a surface vessel, thus complicating interpretations of the
relative contribution of each stimulus to the response. Indeed, the
presence of surface vessels, their approach, and the speed of approach,
all seemed to be significant factors in the response of the Indo-
Pacific humpback dolphins (Ng and Leung, 2003). Low-frequency signals
of the ATOC sound source were not found to affect dive times of
humpback whales in Hawaiian waters (Frankel and Clark, 2000) or to
overtly affect elephant seal dives (Costa et al., 2003). However, they
did produce subtle effects that varied in direction and degree among
the individual seals, illustrating the varied nature of behavioral
effects and consequent difficulty in defining and predicting them.
Lastly, as noted previously, DeRuiter et al. (2013) noted that distance
from a sound source may moderate marine mammal reactions in their study
of Cuvier's beaked whales showing the whales swimming rapidly and
silently away when a sonar signal was 3.4-9.5 km away, while showing no
such reaction to the same signal when the signal was 118 km away even
though the RLs were similar.
Foraging
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. Noise from seismic surveys was not found to impact the
feeding behavior of western gray whales off the coast of Russia
(Yazvenko et al., 2007) and sperm whales engaged in foraging dives did
not abandon dives when exposed to distant signatures of seismic airguns
(Madsen et al., 2006). Balaenopterid whales exposed to moderate SURTASS
LFA sonar demonstrated no responses or change in foraging behavior that
could be attributed to the low-frequency sounds (Croll et al., 2001),
whereas five out of six North Atlantic right whales exposed to an
acoustic alarm interrupted their foraging dives (Nowacek et al., 2004).
Although the received sound pressure level was similar in the latter
two studies, the frequency, duration, and temporal pattern of signal
presentation were different. These factors, as well as differences in
species sensitivity, are
[[Page 7213]]
likely contributing factors to the differential response.
Blue whales exposed to simulated mid-frequency sonar in the
Southern California Bight were less likely to produce low frequency
calls usually associated with feeding behavior (Melc[oacute]n et al.,
2012). However, the authors were unable to determine if suppression of
low frequency calls reflected a change in their feeding performance, or
abandonment of foraging behavior and indicated that implications of the
documented responses are unknown. Further, it is not known whether the
lower rates of calling actually indicated a reduction in feeding
behavior or social contact since the study used data from remotely
deployed, passive acoustic monitoring buoys. In contrast, blue whales
increased their likelihood of calling when ship noise was present, and
decreased their likelihood of calling in the presence of explosive
noise, although this result was not statistically significant
(Melc[oacute]n et al., 2012). Additionally, the likelihood of an animal
calling decreased with the increased received level of mid-frequency
sonar, beginning at a SPL of approximately 110-120 dB re 1 [micro]Pa
(Melc[oacute]n et al., 2012). Results from the 2010-2011 field season
of an ongoing behavioral response study in Southern California waters
indicated that, in some cases and at low received levels, tagged blue
whales responded to mid-frequency sonar but that those responses were
mild and there was a quick return to their baseline activity (Southall
et al., 2011; Southall et al., 2012). Goldbogen et al. (2013) monitored
behavioral responses of tagged blue whales located in feeding areas
when exposed to simulated MFA sonar. Responses varied depending on
behavioral context, with deep feeding whales being more significantly
affected (i.e., generalized avoidance; cessation of feeding; increased
swimming speeds; or directed travel away from the source) compared to
surface feeding individuals that typically showed no change in
behavior. Non-feeding whales also seemed to be affected by exposure.
The authors indicate that disruption of feeding and displacement could
impact individual fitness and health. However, for this to be true, we
would have to assume that an individual whale could not compensate for
this lost feeding opportunity by either immediately feeding at another
location, by feeding shortly after cessation of acoustic exposure, or
by feeding at a later time. There is no indication this is the case for
the proposed SURTASS LFA sonar activities, particularly since SURTASS
LFA sonar training and testing activities take place offshore in open
ocean environments and are fairly spread out and relatively short-term
in nature, unconsumed prey would likely still be available in the
environment in most cases following the cessation of acoustic exposure.
A determination of whether foraging disruptions incur fitness
consequences is informed by estimates of the energetic requirements of
the individuals and the relationship between prey availability,
foraging effort and success, and the life history stage of the animal,
but is also based on an understanding of the magnitude and duration of
the disruption.
Social Relationships
Social interactions between mammals can be affected by noise via
the disruption of communication signals or by the displacement of
individuals. Sperm whales responded to military sonar, apparently from
a submarine, by dispersing from social aggregations, moving away from
the sound source, remaining relatively silent, and becoming difficult
to approach (Watkins et al., 1985). In contrast, sperm whales in the
Mediterranean that were exposed to submarine sonar continued calling
(J. Gordon pers. comm. cited in Richardson et al., 1995). However,
social disruptions must be considered in context of the relationships
that are affected. While some disruptions may not have deleterious
effects, others, such as long-term or repeated disruptions of mother/
calf pairs or interruption of mating behaviors, have the potential to
affect the growth and survival or reproductive effort/success of
individuals.
Vocalizations (Also See Masking Section)
Vocal changes in response to anthropogenic noise can occur across
the repertoire of sound production modes used by marine mammals, such
as whistling, echolocation click production, calling, and singing.
Changes may result in response to a need to compete with an increase in
background noise or may reflect an increased vigilance or startle
response. For example, in the presence of low-frequency active sonar,
humpback whales have been observed to increase the length of their
``songs'' (Miller et al., 2000; Fristrup et al., 2003), possibly due to
the overlap in frequencies between the whale song and the low-frequency
active sonar. A similar compensatory effect for the presence of low-
frequency vessel noise has been suggested for right whales; right
whales have been observed to shift the frequency content of their calls
upward while reducing the rate of calling in areas of increased
anthropogenic noise (Parks et al., 2007). Killer whales off the
northwestern coast of the United States have been observed to increase
the duration of primary calls once a threshold in observing vessel
density (e.g., whale watching) was reached, which has been suggested as
a response to increased masking noise produced by the vessels (Foote et
al., 2004). In contrast, both sperm and pilot whales potentially ceased
sound production during the Heard Island feasibility test (Bowles et
al., 1994), although it cannot be absolutely determined whether the
inability to acoustically detect the animals was due to the cessation
of sound production or the displacement of animals from the area.
Aicken et al. (2005) monitored the behavioral responses of marine
mammals to a new low-frequency active sonar system used by the British
Navy (the United States Navy considers this to be a mid-frequency
source as it operates at frequencies greater than 1,000 Hz). During
those trials, fin whales, sperm whales, Sowerby's beaked whales, long-
finned pilot whales, Atlantic white-sided dolphins, and common
bottlenose dolphins were observed and their vocalizations were
recorded. These monitoring studies detected no evidence of behavioral
responses that the investigators could attribute to exposure to the
low-frequency active sonar during these trials.
Avoidance
Avoidance is the displacement of an individual from an area as a
result of the presence of a sound. Richardson et al. (1995) noted that
avoidance reactions are the most obvious manifestations of disturbance
in marine mammals. Avoidance is qualitatively different from the flight
response, and 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.
However, longer-term displacement is possible and can lead to changes
in abundance or distribution patterns of the species in the affected
region if animals do not become acclimated to the presence of the
chronic sound (Blackwell et al., 2004; Bejder et al., 2006; Teilmann et
al., 2006). Acute avoidance responses have been observed in captive
porpoises and pinnipeds exposed to a number of different sound sources
(Kastelein et al., 2001; Finneran et al., 2003; Kastelein et al.,
2006a; Kastelein et al., 2006b).
[[Page 7214]]
Short-term avoidance of seismic surveys, low-frequency emissions, and
acoustic deterrents have also been noted in wild populations of
odontocetes (Bowles et al., 1994; Goold, 1996, 1998; Stone et al.,
2000; Morton and Symonds, 2002) and to some extent in mysticetes
(Gailey et al., 2007), while long-term or repetitive/chronic
displacement for some dolphin groups and for manatees has been
suggested to result from the presence of chronic vessel noise
(Haviland-Howell et al., 2007; Miksis-Olds et al., 2007).
In 1998, the Navy conducted a Low Frequency Sonar Scientific
Research Program (LFS SRP) specifically to study behavioral responses
of several species of marine mammals to exposure to LF sound, including
one phase that focused on the behavior of gray whales to low frequency
sound signals. The objective of this phase of the LFS SRP was to
determine whether migrating gray whales respond more strongly to
received levels (RL), sound gradient, or distance from the source, and
to compare whale avoidance responses to an LF source in the center of
the migration corridor versus in the offshore portion of the migration
corridor. A single source was used to broadcast LFA sonar sounds at RLs
of 170-178 dB re 1[micro]Pa. The Navy reported that the whales showed
some avoidance responses when the source was moored one mile (1.8 km)
offshore, and located within the migration path, but the whales
returned to their migration path when they were a few kilometers beyond
the source. When the source was moored two miles (3.7 km) offshore,
outside the migration path, responses were much less even when the
source level was increased to achieve the same RLs in the middle of the
migration corridor as whales received when the source was located
within the migration corridor (Clark et al., 1999). In addition, the
researchers noted that the offshore whales did not seem to avoid the
louder offshore source.
Also during the LFS SRP, researchers sighted numerous odontocete
and pinniped species in the vicinity of the sound exposure tests with
LFA sonar. The MF and HF hearing specialists present in the study area
showed no immediately obvious responses or changes in sighting rates as
a function of source conditions. Consequently, the researchers
concluded that none of these species had any obvious behavioral
reaction to LFA sonar signals at received levels similar to those that
produced only minor short-term behavioral responses in the baleen
whales (i.e., LF hearing specialists). Thus, for odontocetes, the
chances of injury and/or significant behavioral responses to SURTASS
LFA sonar would be low given the MF/HF specialists' observed lack of
response to LFA sounds during the LFS SRP and due to the MF/HF
frequencies which these animals are adapted to hear (Clark and
Southall, 2009).
Maybaum (1993) conducted sound playback experiments to assess the
effects of mid-frequency active sonar on humpback whales in Hawaiian
waters. Specifically, she exposed focal pods to sounds of a 3.3-kHz
sonar pulse, a sonar frequency sweep from 3.1 to 3.6 kHz, and a control
(blank) tape while monitoring the behavior, movement, and underwater
vocalizations. The two types of sonar signals differed in their effects
on the humpback whales, but both resulted in avoidance behavior. The
whales responded to the pulse by increasing their distance from the
sound source and responded to the frequency sweep by increasing their
swimming speeds and track linearity. In the Caribbean, sperm whales
avoided exposure to mid-frequency submarine sonar pulses, in the range
of 1000 Hz to 10,000 Hz (IWC, 2005).
Kvadsheim et al. (2007) conducted a controlled exposure experiment
in which killer whales fitted with D-tags were exposed to mid-frequency
active sonar (Source A: a 1.0 s upsweep 209 dB @1-2 kHz every 10 sec
for 10 minutes; Source B: with a 1.0 s upsweep 197 dB @6-7 kHz every 10
sec for 10 min). When exposed to Source A, a tagged whale and the group
it was traveling with did not appear to avoid the source. When exposed
to Source B, the tagged whales, along with other whales that had been
carousel feeding where killer whales cooperatively herd fish schools
into a tight ball towards the surface and feed on the fish which have
been stunned by tail slaps and subsurface feeding (Simila, 1997),
ceased feeding during the approach of the sonar and moved rapidly away
from the source. When exposed to Source B, Kvadsheim and his co-workers
reported that a tagged killer whale seemed to try to avoid further
exposure to the sound field by performing the following behaviors:
Immediately swimming away (horizontally) from the source of the sound;
engaging in a series of erratic and frequently deep dives that seemed
to take it below the sound field; or swimming away while engaged in a
series of erratic and frequently deep dives. Although the sample sizes
in this study are too small to support statistical analysis, the
behavioral responses of the orcas were consistent with the results of
other studies.
In 2007, the first in a series of behavioral response studies (BRS)
on deep diving odontocetes, funded by Navy, and supported by NMFS and
other scientists, showed one beaked whale (Mesoplodon densirostris)
responding to an MF active sonar playback. Tyack et al. (2011)
indicates that the playback began when the tagged beaked whale was
vocalizing at depth (at the deepest part of a typical feeding dive),
following a previous control with no sound exposure. The whale appeared
to stop clicking significantly earlier than usual, when exposed to mid-
frequency signals in the 130-140 dB (rms) received level range. After a
few more minutes of the playback, when the received level reached a
maximum of 140-150 dB, the whale ascended on the slow side of normal
ascent rates with a longer than normal ascent, at which point the
exposure was terminated. The results are from a single experiment and a
greater sample size is needed before robust and definitive conclusions
can be drawn.
Tyack et al. (2011) also indicate that Blainville's beaked whales
(a resident species within the Tongue of the Ocean, Bahamas study area)
appear to be sensitive to noise at levels well below the onset of
expected TTS (approximately 160 dB re: 1[micro]Pa at 1 m). This
sensitivity was manifested by an adaptive movement away from a sound
source. This response was observed irrespective of whether the signal
transmitted was within the bandwidth of MF active sonar, which suggests
that beaked whales may not respond to the specific sound signatures.
Instead, they may be sensitive to any pulsed sound from a point source
in the frequency range of the MF active sonar transmission. The
response to such stimuli appears to involve the beaked whale increasing
the distance between it and the sound source.
Southall et al. (2016) indicates that results from Tyack et al.
(2011), Miller et al. (2015), Stimpert et al. (2014), and DeRuiter et
al. (2013) all demonstrate clear, strong, and pronounced but varied
behavioral changes including sustained avoidance with associated
energetic swimming and cessation of feeding behavior at quite low
received levels (~100 to 135 dB re 1[mu]Pa) for exposures to simulated
or active MF military sonars (1 to 8 kHz) with sound sources
approximately 2 to 5 km away, with a common theme being the context-
dependent nature of the behavioral responses.
In the 2010 SOCAL BRS study, researchers again used controlled
exposure experiments (CEE) to carefully measure behavioral responses of
[[Page 7215]]
individual animals to sound exposures of simulated tactical MF active
sonar and pseudo-random noise. For each sound type, some exposures were
conducted when animals were in a surface feeding (approximately 164 ft
(50 m) or less) and/or socializing behavioral state and others while
animals were in a deep feeding (greater than 164 ft (50 m)) and/or
traveling mode. The researchers conducted the largest number of CEEs on
blue whales (n=19) and of these, 11 CEEs involved exposure to the MF
active sonar sound type. For the majority of CEE transmissions of
either sound type, they noted few obvious behavioral responses detected
either by the visual observers or on initial inspection of the tag
data. The researchers observed that throughout the CEE transmissions,
up to the highest received sound level (absolute RMS value
approximately 160 dB re: 1[mu]Pa with signal-to-noise ratio values over
60 dB), two blue whales continued surface feeding behavior and remained
at a range of around 3,820 ft (1,000 m) from the sound source (Southall
et al., 2011). In contrast, another blue whale (later in the day and
greater than 11.5 mi (18.5 km; 10 nmi) from the first CEE location)
exposed to the same stimulus (MFA) while engaged in a deep feeding/
travel state exhibited a different response. In that case, the blue
whale responded almost immediately following the start of sound
transmissions when received sounds were just above ambient background
levels (Southall et al., 2011). The authors note that this kind of
temporary avoidance behavior was not evident in any of the nine CEEs
involving blue whales engaged in surface feeding or social behaviors,
but was observed in three of the ten CEEs for blue whales in deep
feeding/travel behavioral modes (one involving MFA sonar; two involving
pseudo-random noise) (Southall et al., 2011). Southall et al. (2016)
provided an overview of the Southern California Behavioral Response
Study (SOCAL-BRS). The results of this study, as well as the results of
the DeRuiter et al. (2013) study of Cuvier's beaked whales discussed
above, further illustrate the importance of behavioral context in
understanding and predicting behavioral responses.
Flight Response
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996). Flight responses have been speculated as being a
component of marine mammal strandings associated with MF active sonar
activities (Evans and England, 2001). If marine mammals respond to Navy
vessels that are transmitting active sonar in the same way that they
might respond to a predator, their probability of flight responses
should increase when they perceive that Navy vessels are approaching
them directly, because a direct approach may convey detection and
intent to capture (Burger and Gochfeld, 1981, 1990; Cooper, 1997,
1998). In addition to the limited data on flight response for marine
mammals, there are examples of this response in terrestrial species.
For instance, the probability of flight responses in Dall's sheep (Ovis
dalli dalli) (Frid, 2001), hauled-out ringed seals (Phoca hispida)
(Born et al., 1999), Pacific brant (Branta bernicl nigricans), and
Canada geese (B. Canadensis) increased as a helicopter or fixed-wing
aircraft more directly approached groups of these animals (Ward et al.,
1999). Bald eagles (Haliaeetus leucocephalus) perched on trees
alongside a river were also more likely to flee from a paddle raft when
their perches were closer to the river or were closer to the ground
(Steidl and Anthony, 1996).
Breathing
Variations in respiration naturally occur with different behaviors.
Variations in respiration rate as a function of acoustic exposure can
co-occur with other behavioral reactions, such as a flight response or
an alteration in diving. However, respiration rates in and of
themselves may be representative of annoyance or an acute stress
response. Mean exhalation rates of gray whales at rest and while diving
were found to be unaffected by seismic surveys conducted adjacent to
foraging grounds (Gailey et al., 2007). Studies with captive harbor
porpoises showed increased respiration rates upon introduction of
acoustic alarms (Kastelein et al., 2001; Kastelein et al., 2006a) and
emissions for underwater data transmission (Kastelein et al., 2005).
However, exposing the same acoustic alarm to a striped dolphin under
the same conditions did not elicit a response (Kastelein et al.,
2006a), again highlighting the importance of understanding species
differences in the tolerance of underwater noise when determining the
potential for impacts resulting from anthropogenic sound exposure.
Continued Pre-Disturbance Behavior and Habituation
Under some circumstances, some of the individual marine mammals
that are exposed to active sonar transmissions will continue their
normal behavioral activities. In other circumstances, individual
animals will respond to sonar transmissions at lower received levels
and move to avoid additional exposure or exposures at higher received
levels (Richardson et al., 1995).
It is difficult to distinguish between animals that continue their
pre-disturbance behavior without stress responses, animals that
continue their behavior but experience stress responses (that is,
animals that cope with disturbance), and animals that habituate to
disturbance (that is, they may have experienced low-level stress
responses initially, but those responses abated over time). Watkins
(1986) reviewed data on the behavioral reactions of fin, humpback,
right and minke whales that were exposed to continuous, broadband low-
frequency shipping and industrial noise in Cape Cod Bay. He concluded
that underwater sound was the primary cause of behavioral reactions in
these species of whales and that the whales responded behaviorally to
acoustic stimuli within their respective hearing ranges. Watkins also
noted that whales showed the strongest behavioral reactions to sounds
in the 15 Hz to 28 kHz range, although negative reactions (avoidance,
interruptions in vocalizations, etc.) were generally associated with
sounds that were either unexpected, too loud, suddenly louder or
different, or perceived as being associated with a potential threat
(such as an approaching ship on a collision course). In particular,
whales seemed to react negatively when they were within 100 m of the
source or when received levels increased suddenly in excess of 12 dB
relative to ambient sounds. At other times, the whales ignored the
source of the signal and all four species habituated to these sounds.
Nevertheless, Watkins concluded that whales ignored most sounds in the
background of ambient noise, including sounds from distant human
activities even though these sounds may have had considerable energies
at frequencies well within the whales' range of hearing. Further, he
noted that of the whales observed, fin whales were the most sensitive
of the four species, followed by humpback whales; right whales were the
least likely to be disturbed and generally did not react to low-
amplitude engine noise. By the end of his period of study, Watkins
(1986) concluded that fin and humpback
[[Page 7216]]
whales have generally habituated to the continuous and broadband noise
of Cape Cod Bay while right whales did not appear to change their
response. As mentioned above, animals that habituate to a particular
disturbance may have experienced low-level stress responses initially,
but those responses abated over time. In most cases, this likely means
a lessened immediate potential effect from a disturbance. However,
there is cause for concern where the habituation occurs in a
potentially more harmful situation. For example, animals may become
more vulnerable to vessel strikes once they habituate to vessel traffic
(Swingle et al., 1993; Wiley et al., 1995).
Potential Effects of Behavioral Disturbance
The primary potential impact on marine mammals from exposure to
SURTASS LFA sonar is behavioral response. We note here that not all
behavioral responses rise to the level of take under the MMPA, and not
all take results in significant changes in biologically important
behaviors that are expected to impact individual fitness through
effects on reproductive success or survival. Complexities associated
with evaluation of when behavioral responses are likely to impact
energetics or reproductive success, creating the potential for
population consequences, are becoming clearer as data are compiled on
extensively studied species and energetic models are created (Maresh et
al., 2014; New et al., 2014; and Robinson et al., 2012). There are few
quantitative marine mammal data relating the exposure of marine mammals
to sound to effects on reproduction or survival, though data exist for
terrestrial species to which we can draw comparisons for marine
mammals. Several authors have reported that disturbance stimuli cause
animals to abandon nesting and foraging sites (Sutherland and
Crockford, 1993); cause animals to increase their activity levels and
suffer premature deaths or reduced reproductive success when their
energy expenditures exceed their energy budgets (Daan et al., 1996;
Feare, 1976; Mullner et al., 2004); or cause animals to experience
higher predation rates when they adopt risk-prone foraging or migratory
strategies (Frid and Dill, 2002). Each of these studies addressed the
consequences of animals shifting from one behavioral state (e.g.,
resting or foraging) to another behavioral state (e.g., avoidance or
escape behavior) because of human disturbance or disturbance stimuli.
One consequence of behavioral avoidance results in the altered
energetic expenditure of marine mammals because energy is required to
move and avoid surface vessels or the sound field associated with
active sonar (Frid and Dill, 2002). Most animals can avoid that
energetic cost by swimming away at slow speeds or speeds that minimize
the cost of transport (Miksis-Olds, 2006), as has been demonstrated in
Florida manatees (Miksis-Olds, 2006).
Those energetic costs increase, however, when animals shift from a
resting state, which is designed to conserve an animal's energy, to an
active state that consumes energy the animal would have conserved had
it not been disturbed. Marine mammals that have been disturbed by
anthropogenic noise and vessel approaches are commonly reported to
shift from resting to active behavioral states, which would imply that
they incur an energy cost.
Morete et al. (2007) reported that undisturbed humpback whale cows
that were accompanied by their calves were frequently observed resting
while their calves circled them (milling). When vessels approached, the
amount of time cows and calves spent resting and milling, respectively,
declined significantly. These results are similar to those reported by
Scheidat et al. (2004) for the humpback whales they observed off the
coast of Ecuador.
Constantine and Brunton (2001) reported that bottlenose dolphins in
the Bay of Islands, New Zealand, engaged in resting behavior just five
percent of the time when vessels were within 300 m, compared with
resting 83 percent of the time when vessels were not present. However,
Heenehan et al. (2016) report that results of a study of the response
of Hawaiian spinner dolphins to human disturbance suggest that the key
factor is not the sheer presence or magnitude of human activities, but
whether the activities are directed and focused on dolphins at rest.
This information again illustrates the importance of context in regard
to whether an animal will respond to a stimulus. Miksis-Olds (2006) and
Miksis-Olds et al. (2005) reported that Florida manatees in Sarasota
Bay, Florida, reduced the amount of time they spent milling and
increased the amount of time they spent feeding when background noise
levels increased. Although the acute costs of these changes in behavior
are not likely to exceed an animal's ability to compensate, the chronic
costs of these behavioral shifts are uncertain.
Attention is the cognitive process of selectively concentrating on
one aspect of an animal's environment while ignoring other things
(Posner, 1994). Because animals (including humans) have limited
cognitive resources, there is a limit to how much sensory information
they can process at any time. The phenomenon called ``attentional
capture'' occurs when a stimulus (usually a stimulus that an animal is
not concentrating on or attending to) ``captures'' an animal's
attention. This shift in attention can occur consciously or
unconsciously (e.g., when an animal hears sounds that it associates
with the approach of a predator) and the shift in attention can be
sudden (Dukas, 2002; van Rij, 2007). Once a stimulus has captured an
animal's attention, the animal can respond by ignoring the stimulus,
assuming a ``watch and wait'' posture, or treating the stimulus as a
disturbance and responding accordingly, which includes scanning for the
source of the stimulus or ``vigilance'' (Cowlishaw et al., 2004).
Vigilance is normally an adaptive behavior that helps animals
determine the presence or absence of predators, assess their distance
from conspecifics, or attend to cues from prey (Bednekoff and Lima,
1998; Treves, 2000). Despite those benefits, vigilance comes at a cost;
when animals focus their attention on specific environmental cues, they
are not attending to other activities, such as foraging. These costs
have been documented best in foraging animals, where vigilance has been
shown to substantially reduce feeding rates (Saino, 1994; Beauchamp and
Livoreil, 1997; Fritz et al., 2002). Animals will spend more time being
vigilant, which may translate to less time foraging or resting, when
disturbance stimuli approach them more directly, remain at closer
distances, have a greater group size (e.g., multiple surface vessels),
or when they co-occur with times that an animal perceives increased
risk (e.g., when they are giving birth or accompanied by a calf). Most
of the published literature suggests that direct approaches will
increase the amount of time animals will dedicate to being vigilant. An
example of this concept with terrestrial species involved bighorn sheep
and Dall's sheep, which dedicated more time to being vigilant, and
spent less time resting or foraging, when aircraft made direct
approaches over them (Frid, 2001). Vigilance has also been documented
in pinnipeds at haul out sites where resting may be disturbed when
seals become alerted and/or flush into the water due to a variety of
disturbances, which may be anthropogenic (noise and/or visual stimuli)
or due to other natural causes such as other pinnipeds (Richardson et
al., 1995; Southall et al., 2007;
[[Page 7217]]
VanBlaricom, 2010; and Lozano and Hente, 2014).
Several authors have established that long-term and intense
disturbance stimuli can cause population effects by reducing the
physical condition of individuals that have been disturbed, followed by
reduced reproductive success, reduced survival, or both (Daan et al.,
1996; Madsen, 1994; White, 1985). For example, Madsen (1994) reported
that pink-footed geese (Anser brachyrhynchus) in undisturbed habitat
gained body mass and had about a 46 percent reproductive success rate
compared with geese in disturbed habitat (being consistently scared off
the fields on which they were foraging) which did not gain mass and had
a 17 percent reproductive success rate. Similar reductions in
reproductive success have been reported for other non-marine mammal
species; for example, mule deer (Odocoileus hemionus) disturbed by all-
terrain vehicles (Yarmoloy et al., 1988), caribou (Rangifer tarandus
caribou) disturbed by seismic exploration blasts (Bradshaw et al.,
1998), and caribou disturbed by low-elevation military jet flights
(Luick et al., 1996; Harrington and Veitch, 1992). Similarly, a study
of elk (Cervus elaphus) that were disturbed experimentally by
pedestrians concluded that the ratio of young to mothers was inversely
related to disturbance rate (Phillips and Alldredge, 2000).
The primary mechanism by which increased vigilance and disturbance
appear to affect the fitness of individual animals is by disrupting an
animal's time budget, reducing the time they might spend foraging and
resting (which increases an animal's activity rate and energy demand
while decreasing their caloric intake/energy). As an example of this
concept with terrestrial species involved, a study of grizzly bears
(Ursus horribilis) during July and August 1992 reported that bears
disturbed by hikers reduced their energy intake by an average of 12
kilocalories/min (50.2 x 10\3\ kiloJoules/min), and spent energy
fleeing or acting aggressively toward hikers (White et al., 1999).
Alternately, Ridgway et al. (2006) reported that increased vigilance in
captive bottlenose dolphins exposed to sound over a five-day period in
open-air, open-water enclosures in San Diego Bay did not cause any
sleep deprivation or stress effects such as changes in cortisol or
epinephrine levels.
On a related note, many animals perform vital functions, such as
feeding, resting, traveling, and socializing, on a diel cycle (24-hr
cycle). Behavioral reactions to noise exposure (such as disruption of
critical life functions, displacement, or avoidance of important
habitat) are more likely to be significant for fitness if they last
more than one diel cycle or recur on subsequent days (Southall et al.,
2007). Consequently, a behavioral response lasting less than one day
and not recurring on subsequent days is not considered particularly
significant unless it could directly affect reproduction or survival
(Southall et al., 2007). It is important to note the difference between
behavioral reactions lasting or recurring over multiple days and
anthropogenic activities lasting or recurring over multiple days. For
example, at-sea SURTASS LFA sonar training and testing activities last
for multiple days, but this does not necessarily mean individual
animals will be exposed to those exercises for multiple days or exposed
in a manner that would result in a sustained behavioral response due to
nature of these activities (few vessels spread out in open ocean
environments operating fairly sporadically for relatively short term
timeframes).
In order to understand how the effects of activities may or may not
impact species and stocks of marine mammals, it is necessary to
understand not only what the likely disturbances are going to be, but
how those disturbances are likely to affect the reproductive success
and survivorship of individuals, and then how those impacts to
individuals translate to population-level effects. Following on the
earlier work of a committee of the U.S. National Research Council (NRC,
2005), an effort by New et al. (2014) termed ``Potential Consequences
of Disturbance (PCoD)'' outlined an updated conceptual model of the
relationships linking disturbance to changes in behavior and
physiology, health, vital rates, and population dynamics. In this
framework, behavioral and physiological changes can have direct (acute)
effects on vital rates, such as when changes in habitat use or
increased stress levels raise the probability of mother-calf separation
or predation; they can have indirect and long-term (chronic) effects on
vital rates, such as when changes in time/energy budgets or increased
disease susceptibility affect health, which then later affect vital
rates; or they can have no effect to vital rates. In addition to
outlining this general framework and compiling the relevant literature
that supports it, the authors chose four example species for which
extensive long-term monitoring data exist (southern elephant seals,
North Atlantic right whales, Ziphidae beaked whales, bottlenose
dolphins, harbor porpoise, and others) and developed state-space
energetic models that can be used to effectively forecast longer-term,
population-level impacts to these species from behavioral changes. An
updated study (National Academies, 2017) addressed approaches to
understanding the cumulative effects of stressors (i.e., stressors from
multiple activities) on marine mammals.
Pirotta et al. (2018) reviewed the application of the PCoD
framework to marine mammal populations, providing an updated synopsis
of studies that have been completed and approaches that have been used
to model effects in the framework. Farmer et al. (2018) applied the
PCoD framework to develop a probabilistic framework for quantitatively
assessing the cumulative impacts of oil and sound exposure to sperm
whales in the Northern Gulf of Mexico. The authors concluded that
uncertainty in their results emphasized a need for further controlled
exposure experiments to generate behavioral disturbance dose-response
curves and detailed evaluation of individual resilience following
disturbance events. While these are very specific models with specific
data requirements that cannot yet be applied to project-specific risk
assessments or for the majority of species, they are a critical first
step towards being able to quantify the likelihood of a population
level effect. However, as noted above, due to the nature of the SURTASS
LFA sonar training and testing activities, the potential for masking,
behavioral effects, and stress would be limited, so the potential for
population level effects would also be limited (See relevant sections,
above). This potential is further reduced due to implementation of the
monitoring and mitigation measures discussed below (See Proposed
Mitigation and Proposed Monitoring sections below).
Stranding and Mortality
The definition for a stranding under the MMPA is that (A) a marine
mammal is dead and is (i) on a beach or shore of the United States; or
(ii) in waters under the jurisdiction of the United States (including
any navigable waters); or (B) a marine mammal is alive and is (i) on a
beach or shore of the United States and is unable to return to the
water; (ii) on a beach or shore of the United States and, although able
to return to the water, is in need of apparent medical attention; or
(iii) in the waters under the jurisdiction of the United States
(including any navigable waters), but is unable to return to its
natural habitat under its own power or without assistance (16 U.S.C.
1421h).
[[Page 7218]]
Marine mammals are known to strand for a variety of reasons, such
as infectious agents, biotoxicosis, starvation, fishery interaction,
ship strike, unusual oceanographic or weather events, sound exposure,
or combinations of these stressors sustained concurrently or in series.
However, the cause or causes of most strandings are unknown (Geraci et
al., 1976; Eaton, 1979; Odell et al., 1980; Best, 1982). Numerous
studies suggest that the physiology, behavior, habitat relationships,
age, or condition of cetaceans may cause them to strand or might
predispose them to strand when exposed to another phenomenon. These
suggestions are consistent with the conclusions of numerous other
studies that have demonstrated that combinations of dissimilar
stressors commonly combine to kill an animal or dramatically reduce its
fitness, even though one exposure without the other does not produce
the same result (Chroussos, 2000; Creel, 2005; Fair and Becker, 2000;
Moberg, 2000; Relyea, 2005a, 2005b, Romero, 2004; Sih et al., 2004).
In 1992, Congress amended the MMPA to establish the Marine Mammal
Health and Stranding Response Program (MMHSRP) under authority of NMFS.
The MMHSRP was created out of concern over marine mammal mortalities,
to formalize the stranding response process, to focus efforts being
initiated by numerous local stranding organizations, and as a result of
public concern.
Strandings Associated With Active Sonar
Several sources have published lists of mass stranding events of
cetaceans in an attempt to identify relationships between those
stranding events and military active sonar (Hildebrand, 2004; IWC,
2005; Taylor et al., 2004). For example, based on a review of stranding
records between 1960 and 1995, the International Whaling Commission
(2005) concluded that, out of eight mass stranding events reported from
the mid-1980s to the summer of 2003, most had been coincident with the
use of tactical MF active sonar and most involved beaked whales.
However, these reports rarely talk about the number of strandings that
are not associated with sonar exercises, which number in the thousands.
According to Bernaldo de Quiros et al. (2019) a review of current
knowledge on beaked whale atypical mass strandings associated with MF
active sonar suggests that effects vary among individuals or
populations, and predisposing factors may contribute to individual
outcomes. Differences between tactical MF sonar and SURTASS LFA sonar,
as well as the potential for strandings due to SURTASS LFA sonar, are
addressed further below.
Over the past 23 years, there have been five mass stranding events
coincident with military MF active sonar use in which exposure to sonar
is believed to have been a contributing factor: Greece (1996); the
Bahamas (2000); Madeira (2000); Canary Islands (2002); and Spain
(2006). NMFS refers the reader to DoN (2013) for a report on these
strandings associated with Navy sonar activities; Cox et al. (2006) for
a summary of common features shared by the strandings events in Greece
(1996), Bahamas (2000), Madeira (2000), and Canary Islands (2002); and
Fernandez et al. (2005) for an additional summary of the Canary Islands
2002 stranding event. Additionally, in 2004, during the Rim of the
Pacific (RIMPAC) exercises, between 150 and 200 usually pelagic melon-
headed whales occupied the shallow waters of Hanalei Bay, Kauai, Hawaii
for over 28 hours. NMFS determined that mid-frequency active sonar
(MFAS) was a plausible, if not likely, contributing factor in what may
have been a confluence of events that led to the Hanalei Bay stranding.
A number of other stranding events coincident with the operation of
MFAS, including the death of beaked whales or other species (minke
whales, dwarf sperm whales, pilot whales), have been reported. However,
the majority have not been investigated to the degree necessary to
determine the cause of the stranding and only one of these stranding
events, the Bahamas (2000), was associated with exercises conducted by
the U.S. Navy. Most recently, the Independent Scientific Review Panel
investigating potential contributing factors to a 2008 mass stranding
of melon-headed whales in Antsohihy, Madagascar, released its final
report suggesting that the stranding was likely initially triggered by
an industry seismic survey. This report suggests that the operation of
a commercial high-powered 12 kHz multi-beam echosounder during an
industry seismic survey was a plausible and likely initial trigger that
caused a large group of melon-headed whales to leave their typical
habitat and then ultimately strand as a result of secondary factors
such as malnourishment and dehydration. The report indicates that the
risk of this particular convergence of factors and ultimate outcome is
likely very low, but recommends that the potential be considered in
environmental planning.
In the event that Navy personnel (uniformed military, civilian, or
contractors conducting Navy work) associated with operating a SURTASS
LFA sonar-equipped vessel discover a live or dead stranded marine
mammal at sea, the Navy shall report the incident to NMFS in accordance
with the Stranding and Notification Plan, available at https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-navy-
operations-surveillance-towed-array-sensor-system-0. In addition, in
the event of a ship strike of a marine mammal by any SURTASS LFA sonar-
equipped vessel, the Navy will also report the incident to NMFS in
accordance with the Stranding and Notification Plan (available at
https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-
navy-operations-surveillance-towed-array-sensor-system-0). If NMFS
personnel determine that the circumstances of any marine mammal
stranding suggests investigation of the association of Navy SURTASS LFA
sonar training and testing activities is warranted, and an
investigation is being pursued, NMFS would submit a written request to
Navy asking that they provide the requested initial information as soon
as possible, but not later than seven business days after the request
is received, per the Stranding and Notification Plan. Finally, in the
event of a live stranding (or near-shore atypical milling), NMFS would
advise the Navy of the need to implement shutdown procedures for any
use of SURTASS LFA sonar within 50 km (27 nmi) of the live stranding.
Shutdown procedures are not related to the investigation of the
cause of the stranding and their implementation is not intended to
imply that Navy activity is the cause of the stranding. Rather,
shutdown procedures are intended to protect marine mammals exhibiting
indicators of distress by minimizing their exposure to possible
additional stressors, regardless of the factors that contributed to the
stranding.
Potential for Stranding From LFA Sonar
There is no empirical evidence of strandings of marine mammals
associated with the employment of SURTASS LFA sonar since its use began
in the early 2000s. Moreover, both the system acoustic characteristics
and the operational parameters of SURTASS LFA sonar differ from MFA
sonars. SURTASS LFA sonars use frequencies generally below 1,000 Hz,
with relatively long signals (pulses) on the order of 60 sec, while MF
sonars use frequencies greater than 1,000 Hz with relatively short
signals on the order of 1 sec. SURTASS LFA sonars involve use of one
slower-moving vessel operating
[[Page 7219]]
far from shore, as opposed to the faster-moving, multi-vessel MFA sonar
training scenarios operating in closer proximity to shore that have
been co-incident with strandings.
As discussed previously, Cox et al. (2006) provided a summary of
common features shared by the stranding events related to MF sonar in
Greece (1996), Bahamas (2000), and Canary Islands (2002). These
included deep water close to land (such as offshore canyons), presence
of an acoustic waveguide (surface duct conditions), and periodic
sequences of transient pulses (i.e., rapid onset and decay times)
generated at depths less than 32.8 ft (10 m) by sound sources moving at
speeds of 2.6 m/s (5.1 knots) or more during sonar operations (D'Spain
et al., 2006). These features are not similar to LFA sonar activities.
First, the Navy will not test and train with SURTASS LFA sonar such
that RLs are greater than 180 dB within 22 km (12 nmi) of any
coastline, ensuring that sound levels are at reduced levels at a
sufficient distance from land. Secondly, when transmitting, the ship
typically operates at 1.5-2.5 m/s (3-5 knots), speeds that are less
than those found in Cox et al. (2009). Finally, the center of the
vertical line array (source) is at a depth of approximately 400 ft
(121.9 m), reducing the sounds that are transmitted at depths above
32.8 ft (10 m). Also, the LFA sonar signal is transmitted at depths
well below 32.8 ft (10 m). While there was an LF component in the Greek
stranding in 1996, only MF components were present in the strandings in
the Bahamas in 2000, Madeira in 2000, and the Canary Islands in 2002.
The International Council for the Exploration of the Sea (ICES) in its
``Report of the Ad-Hoc Group on the Impacts of Sonar on Cetaceans and
Fish'' raised the same issues as Cox et al. (2006), stating that the
consistent association of MF sonar in the Bahamas, Madeira, and Canary
Islands strandings suggest that it was the MF component, not the LF
component, in the NATO sonar that triggered the Greek stranding of 1996
(ICES, 2005). The ICES (2005) report concluded that no strandings,
injury, or major behavioral change have been associated with the
exclusive use of LF sonar.
Potential Effects of Vessel Movement and Collisions
Vessel movement in the vicinity of marine mammals has the potential
to result in either a behavioral response or a direct physical
interaction. Both scenarios are discussed below.
Behavioral Responses to Vessels (Movement and Noise)
There are limited data concerning marine mammal behavioral
responses to vessel traffic and vessel noise, and a lack of consensus
among scientists with respect to what these responses mean or whether
they result in short-term or long-term adverse effects. As discussed
previously, behavioral responses are context-dependent, complex, and
influenced to varying degrees by a number of factors. For example, an
animal may respond differently to a sound emanating from a ship that is
moving towards the animal than it would to an identical received level
coming from a vessel that is moving away, or to a ship traveling at a
different speed or at a different distance from the animal. In cases
where vessels actively approach marine mammals (e.g., whale watching or
dolphin watching boats), scientists have documented that animals
exhibit altered behavior such as increased swimming speed, erratic
movement, and active avoidance behavior (Bursk, 1983; Acevedo, 1991;
Baker and MacGibbon, 1991; Trites and Bain, 2000; Constantine et al.,
2003), reduced blow interval (Ritcher et al., 2003), disruption of
normal social behaviors (Lusseau, 2003, 2006), and the shift of
behavioral activities which may increase energetic costs (Constantine
et al., 2003, 2004; Heenehan et al., 2016). However, at greater
distances, the nature of vessel movements could also potentially have
no, or very little, effect on the animal's response to the sound. In
those cases where there is a busy shipping lane or a large amount of
vessel traffic, marine mammals may experience acoustic masking
(Hildebrand, 2005) if they are present in the area (e.g., killer whales
in Puget Sound; Foote et al., 2004; Holt et al., 2008). In any case, a
full description of the suite of factors that elicited a behavioral
response would require a mention of the vicinity, speed and movement of
the vessel, and other factors. A detailed review of marine mammal
reactions to ships and boats is available in Richardson et al. (1995).
For each of the marine mammal taxonomy groups, Richardson et al. (1995)
provides the following assessment regarding cetacean reactions to
vessel traffic:
Toothed whales: Toothed whales sometimes show no avoidance reaction
to vessels, and may even approach them; however, avoidance can occur,
especially in response to vessels of types used to chase or hunt the
animals. Such avoidance may cause temporary displacement, but we know
of no clear evidence of toothed whales abandoning significant parts of
their range because of vessel traffic.
Baleen whales: Baleen whales seem to ignore low-level sounds from
distant or stationary vessels, and some whales even approach the
sources of these sounds. When approached slowly and non-aggressively,
whales often exhibit slow and inconspicuous avoidance maneuvers.
However, in response to strong or rapidly changing vessel noise, baleen
whales often interrupt their normal behavior and swim rapidly away, and
avoidance is especially strong when a boat heads directly toward the
whale.
Behavioral responses to stimuli are complex and influenced to
varying degrees by a number of factors, such as species, behavioral
contexts, geographical regions, source characteristics (moving or
stationary, speed, direction, etc.), prior experience of the animal and
physical status of the animal. For example, studies have shown that
beluga whales' reactions varied when exposed to vessel noise and
traffic. In some cases, naive beluga whales exhibited rapid swimming
from ice-breaking vessels up to 80 km (49.7 mi) away, and showed
changes in surfacing, breathing, diving, and group composition in the
Canadian high Arctic where vessel traffic is rare (Finley et al.,
1990). In other cases, beluga whales were more tolerant of vessels, but
responded differentially to certain vessels and operating
characteristics by reducing their calling rates (especially older
animals) in the St. Lawrence River where vessel traffic is common
(Blane and Jaakson, 1994). In Bristol Bay, Alaska, beluga whales
continued to feed when surrounded by fishing vessels and resisted
dispersal even when purposefully harassed (Fish and Vania, 1971).
In reviewing more than 25 years of whale observation data, Watkins
(1986) concluded that whale reactions to vessel traffic were ``modified
by their previous experience and current activity: Habituation often
occurred rapidly, attention to other stimuli or preoccupation with
other activities sometimes overcame their interest or wariness of
stimuli.'' Watkins noticed that over the years of exposure to ships in
the Cape Cod area, minke whales changed from frequent positive interest
(e.g., approaching vessels) to generally uninterested reactions; fin
whales changed from mostly negative (e.g., avoidance) to uninterested
reactions; right whales apparently continued the same variety of
responses (negative, uninterested, and positive responses) with little
change; and humpbacks
[[Page 7220]]
dramatically changed from mixed responses that were often negative to
reactions that were often strongly positive. Watkins (1986) summarized
that whales near shore generally have become less wary of boats and
their noises, and they have appeared to be less easily disturbed, even
in regions with low vessel traffic. In locations with intense shipping
and repeated approaches by boats (such as the whale-watching areas),
more whales had positive reactions to familiar vessels, and they also
occasionally approached other boats and yachts in the same ways.
Although the radiated sound from Navy vessels will be audible to
marine mammals over a large distance, it is unlikely that animals will
respond behaviorally (in a manner that NMFS would consider indicative
of harassment under the MMPA) to low-level distant ship noise as the
animals in the area are likely to be habituated to such noises (Nowacek
et al., 2004). In addition, given that SURTASS LFA sonar-equipped
vessels are small, relatively quiet, and the fact that they are not
idle in one spot nor necessarily encircling to contain animals, a
significant disruption of normal behavioral pattern that would make
ship movements rise to the level of take by Level B harassment is
unlikely. In light of these facts, NMFS does not expect the movements
of the Navy's SURTASS LFA sonar vessels to result in take by Level B
harassment.
Vessel Strike
Ship strikes of cetaceans can cause immediate death or major
injury, which may eventually lead to the death of the animal. An animal
at the surface could be struck directly by a vessel, a surfacing animal
could hit the bottom of a vessel, or an animal just below the surface
could be cut by a vessel's propeller. The severity of injuries
typically depends on the size and speed of the vessel (Knowlton and
Kraus, 2001; Laist et al., 2001; Vanderlaan and Taggart, 2007).
The most vulnerable marine mammals are those that spend extended
periods of time at the surface, often to restore oxygen levels within
their tissues after deep dives (e.g., the sperm whale). In addition,
some large, slow moving baleen whales, such as the North Atlantic right
whale, seem generally unresponsive to vessel sound, making them more
susceptible to vessel collisions (Nowacek et al., 2004). Some smaller
marine mammals (e.g., bottlenose dolphin) move quickly through the
water column and purposefully approach ships to ride the bow wave of
large ships without any injury.
An examination of all known ship strikes from all shipping sources
(civilian and military) indicates vessel speed is a principal factor in
whether a vessel strike results in death (Knowlton and Kraus, 2001;
Laist et al., 2001; Jensen and Silber, 2003; Vanderlaan and Taggart,
2007). In assessing records in which vessel speed was known, Laist et
al. (2001) found a direct relationship between the occurrence of a
whale strike and the speed of the vessel involved in the collision,
with most deaths occurring when a vessel was traveling in excess of
14.9 mph (24.1 km/hr; 13 kts).
Jensen and Silber (2004) detailed 292 records of known or probable
ship strikes of all large whale species from 1975 to 2002. Of these,
vessel speed at the time of collision was reported for 58 cases. Of
these cases, 39 (or 67 percent) resulted in serious injury or death (19
of those resulted in serious injury as determined by blood in the
water; propeller gashes or severed tailstock, and fractured skull, jaw,
vertebrae; hemorrhaging; massive bruising or other injuries noted
during necropsy and 20 resulted in death). Operating speeds of vessels
that struck various species of large whales ranged from 2 to 51 kts,
with the majority (79 percent) of these strikes occurring at speeds of
13 kts or greater. The average speed that resulted in serious injury or
death was 18.6 kts. Pace and Silber (2005) found that the probability
of death or serious injury increased rapidly with increasing vessel
speed. Specifically, the predicted probability of serious injury or
death increased from 45 percent to 75 percent as vessel speed increased
from 10 to 14 kts, and exceeded 90 percent at 17 kts. Higher speeds
during collisions result in greater force of impact, but higher speeds
also appear to increase the chance of severe injuries or death by
pulling whales toward the vessel. While modeling studies have suggested
that hydrodynamic forces pulling whales toward the vessel hull increase
with increasing vessel speed (Clyne, 1999; Knowlton et al., 1995), this
is inconsistent with Silber et al. (2010), which demonstrated that
there is no such relationship (i.e., hydrodynamic forces are
independent of speed).
The Jensen and Silber (2004) report notes that the database
represents a minimum number of collisions, because the vast majority
probably goes undetected or unreported. In contrast, while ship strike
is not likely due to SURTASS LFA sonar training and testing activities
due to the slow ship speeds and higly effective monitoring associated
with these activities, Navy vessels are likely to detect any strike
that would occur (due to monitoring), and they are required to report
all ship strikes involving marine mammals. Overall, the percentage of
Navy vessel traffic relative to overall large shipping vessel traffic
is very small (on the order of two percent). Moreover, as mentioned
previously, there are currently only four SURTASS LFA sonar vessels,
which would equate to an extremely small percentage of the total vessel
traffic. Although the Navy does anticipate additional vessels beginning
in year 2024 (year 5), it is not reasonable to assume additional
vessels would substantially add to the total vessel traffic.
The Navy's testing and training activities of SURTASS LFA sonar
vessels is extremely small in scale compared to the number of
commercial ships transiting at higher speeds in the same areas on an
annual basis. The probability of vessel and marine mammal interactions
occurring during SURTASS LFA sonar activities is unlikely due to the
surveillance vessel's slow operational speed, which is typically 3.4
mph (5.6 km/hr; 3 kts). Outside of SURTASS LFA sonar activities, each
vessel's cruising speed would be a maximum of approximately 11.5 to
14.9 mph (18.5 to 24.1 km/hr; 10 to 13 kts) which is generally below
the speed at which studies have noted reported increases of marine
mammal injury or death (Laist et al., 2001).
As a final point, the SURTASS LFA surveillance vessels have a
number of other advantages for avoiding ship strikes as compared to
most commercial merchant vessels, including the following: The
catamaran-type split hull shape and enclosed propeller system of the
Navy's T-AGOS ships; the bridge of T-AGOS ships positioned forward of
the centerline, offering good visibility ahead of the bow and good
visibility aft to visually monitor for marine mammal presence; lookouts
posted during activities scan the ocean for marine mammals and must
report visual alerts of marine mammal presence to the Deck Officer;
lookouts receive extensive training that covers the fundamentals of
visual observing for marine mammals and information about marine
mammals and their identification at sea; and SURTASS LFA vessels travel
at low speed (3-4 kts (approximately 3.4 mph; 5.6 km/hr)) with deployed
arrays. Lastly, the use of passive and active acoustic monitoring for
marine mammals as mitigation measures to monitor for marine mammals
along with visual marine mammal observers would detect cetaceans well
in advance of any
[[Page 7221]]
potential ship strike distance during SURTASS LFA sonar training and
testing activities (for a thorough discussion of mitigation measures,
please see the Proposed Mitigation section later in this document).
Due to the reasons described above (low probability of vessel/
marine mammal interactions; relatively slow vessel speeds; and high
probability of detection due to applied mitigation measures), and the
fact that there have been no ship strikes in the 17-year history of
SURTASS LFA sonar activities, the Navy and NMFS have determined that
take of marine mammals by vessel strike is highly unlikely. Therefore,
the Navy has not requested any take of marine mammals due to ship
strike, nor is NMFS considering any authorization of take due to ship
strike.
Results From Past Monitoring
From the commencement of SURTASS LFA sonar use in 2002 through the
present, neither LFA sonar, nor operation of the T-AGOS vessels, has
been associated with any mass or individual strandings of marine
mammals temporally or spatially. In addition, the Navy's required
monitoring reports indicate that there have been no apparent avoidance
reactions observed, and no takes by Level A harassment due to SURTASS
LFA sonar since its use began in 2002. In summary, results of the
analyses conducted for SURTASS LFA sonar and the previous 17 years of
documented results support the determination that the only takes
anticipated would be short-term Level B harassment of affected marine
mammal stocks.
Effects on Marine Mammal Habitat Including Prey
Anticipated Effects on Habitat Use--SURTASS LFA sonar activities
would not affect the physical characteristics of marine mammal
habitats. Based on the following information; the supporting
information included in the Navy's application; the 2001, 2007, 2012,
and 2017 NEPA documents; and 2018 DSEIS/SOEIS, NMFS has preliminarily
determined that SURTASS LFA sonar activities are not likely to
adversely impact marine mammal habitat use. For reasons described
above, unless the sound source is stationary and/or continuous over a
long duration in one area, the effects of the introduction of sound
into the environment are generally considered to have a less severe
impact on marine mammal habitat than actions involving physical
alteration of the habitat. Marine mammals may be temporarily displaced
from areas where SURTASS LFA training and testing activities are
occurring to avoid noise exposure (see above), i.e., due to impacts on
acoustic habitat, but the habitat will not be physically altered and
will likely be available for use again after the activities have ceased
or moved out of the area. In addition, pings from SURTASS LFA sonar are
very sporadic and are not generally repeated in the exact same area.
SURTASS LFA training and testing activities would not result in the
deposition of materials, change bathymetry, strike/modify features, or
cause any physical alterations to marine mammal habitat.
Anticipated Impacts on Prey Species (Invertebrates and Fish)--The
Navy's proposed SURTASS LFA sonar activities could potentially affect
marine mammal habitat through the introduction of pressure and sound
into the water column, which in turn could impact prey species of
marine mammals. Among invertebrates, only cephalopods (octopus and
squid) and decapods (lobsters, shrimps, and crabs) are known to sense
LF sound (Packard et al., 1990; Budelmann and Williamson, 1994; Lovell
et al., 2005; Mooney et al., 2010). Popper and Schilt (2008) stated
that, like fish, some invertebrate species produce sound, possibly
using it for communications, territorial behavior, predator deterrence,
and mating. Well known sound producers include the lobster (Panulirus
spp.) (Latha et al., 2005), and the snapping shrimp (Alpheus
heterochaelis) (Herberholz and Schmitz, 2001).
Andre et al. (2011) exposed four cephalopod species (Loligo
vulgaris, Sepia officinalis, Octopus vulgaris, and Ilex coindetii) to
two hours of continuous sound from 50 to 400 Hz at 157 5
dB re: 1 [mu]Pa. They reported lesions to the sensory hair cells of the
statocysts of the exposed animals that increased in severity with time.
These results indicate that cephalopods are particularly sensitive to
low-frequency sound. The SURTASS DSEIS/SOEIS (Chapter 4) notes that a
follow-on study was conducted with Mediterranean and European squid
(Octopus vulgaris, and Ilex coindetii) that included controls
(Sol[eacute] et al., 2013), which found a similar result as Andre et
al. (2011) with permanent and substantial alteration of the sensory
hair cells of the statocysts. Aguilar de Soto et al. (2013) exposed New
Zealand scallop larvae (Pecten novaezeandiae) to recorded signals from
a seismic airgun survey every three seconds for up to 70 hours. They
found a delay in development and malformations of the larvae in the
noise-exposed samples. However, SURTASS LFA sonar has none of the same
characteristics as the acoustic sources used in these studies. The time
sequence of exposure from low-frequency sources in the open ocean would
be about once every 10 to 15 min for SURTASS LFA sonar. Therefore, the
study's sound exposures were longer in duration and higher in energy
than any exposure a marine mammal would likely ever receive from
SURTASS LFA sonar and acoustically very different than a free field
sound to which animals would be exposed in the real world. SURTASS LFA
sonar activities would only be expected to have a lasting impact on
these animals if they are within a few tens of meters from the source,
which is not anticipated to occur due to monitoring and mitigation
measures described below. In conclusion, NMFS does not expect any
short- or long-term effects to invertebrates from SURTASS LFA sonar
activities.
The SURTASS DSEIS/SOEIS includes a detailed discussion of the
effects of active sonar on marine fish and several studies on the
effects of both Navy sonar and seismic airguns that are relevant to
potential effects of SURTASS LFA sonar on osteichthyes (bony fish). In
the most pertinent of these, the Navy funded independent scientists to
analyze the effects of SURTASS LFA sonar on fish (Popper et al., 2007;
Halvorsen et al., 2006) and on the effects of SURTASS LFA sonar on fish
physiology (Kane et al., 2010).
Several studies on the effects of SURTASS LFA sonar sounds on three
species of fish (rainbow trout, channel catfish, and hybrid sunfish)
examined long-term effects on sensory hair cells of the ear. In all
species, even up to 96 hours post-exposure, there were no indications
of damage to sensory cells (Popper et al., 2005a, 2007; Halvorsen et
al., 2006). Recent results from direct pathological studies of the
effects of LFA sounds on fish (Kane et al., 2010) provide evidence that
SURTASS LFA sonar sounds at relatively high received levels (up to 193
dB re: 1 [mu]Pa at 1 m) have no pathological effects or short- or long-
term effects to ear tissue on the species of fish that have been
studied. Therefore, the transmission of SURTASS LFA sonar is unlikely
to impact fish populations, and thus would not result in indirect
effects on marine mammals by affecting their prey base.
Estimated Take of Marine Mammals
This section indicates the number of takes that NMFS is proposing
to authorize, which is based on the amount
[[Page 7222]]
of take that NMFS anticipates could or is 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 preliminarily 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 estimated for authorization, are appropriate and
based on the best available science.
Level B Harassment is the only means of take expected to result
from these activities. For military readiness activities, 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 behavior 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).
As described previously in the Potential Effects of the Specified
Activity on Marine Mammals and their Habitat section, based on the
specified activity operational parameters and proposed mitigation, only
Level B Harassment is expected to occur and therefore proposed to be
authorized. Based on the nature of the activities and the anticipated
effectiveness of the mitigation measures, take by Level A Harassment,
serious injury, or mortality is neither anticipated nor proposed to be
authorized.
Generally speaking, for acoustic impacts we estimate 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 Level B harassment (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, as well as
the model the Navy used to incorporate these components to predict
impacts, and present the take estimate.
Density Estimates
To derive density estimates, direct estimates from line-transect
surveys that occurred in or near each of the 15 modeled areas
(described in the Description of Marine Mammals in the Area of the
Specified Activities section above) were utilized first (e.g., Bradford
et al., 2017). When density estimates were not available from a survey
in the Study Area, density estimates from a region with similar
oceanographic characteristics were extrapolated to the operational
area. Densities for some model areas were also derived from the Navy's
Marine Species Density Database (DoN, 2018). Last, density estimates
are usually not available for rare marine mammal species or for those
that have been newly defined (e.g., Deraniyagala's beaked whale). For
such species, a low density estimate of 0.0001 animals per square
kilometer (animals/km\2\) was used in the risk analysis to reflect the
low probability of occurrence in a specific model area. Further,
density estimates are sometimes pooled for species of the same genus if
sufficient data are not available to compute a density for individual
species or the species are difficult to distinguish at sea. This is
often the case for beaked whales (Mesoplodon spp) as well as the pygmy
and dwarf sperm whales (Kogia spp), which is why densities were pooled
for these species in certain model areas. Density estimates are
available for these species groups rather than the individual species
in model areas 1, 2, 3, 5, 6, and 7 for Kogia spp, and in model area 8
for Mesoplodon spp. Density information is provided in Tables 2-16
above, and is also available in the Navy's application (Table 3-2,
Pages 3-6 through 3-25).
SURTASS LFA Sonar Behavioral Response Function
The Navy uses a behavioral response function to estimate the number
of behavioral responses that would qualify as Level B behavioral
harassment under the MMPA. A wide range of behavioral reactions may
qualify as Level B harassment under the MMPA, including but not limited
to avoidance of the sound source, temporary changes in vocalizations or
dive patterns, temporary avoidance of an area, or temporary disruption
of feeding, migrating, or reproductive behaviors. The estimates
calculated using the behavioral response function do not differentiate
between the different types of potential behavioral reactions, nor do
the estimates provide information regarding the potential fitness or
other biological consequences of the reactions on the affected
individuals.
The definition of Level B harassment for military readiness
activities contemplates the disruption of behavioral patterns to the
point where they are abandoned or significantly altered. It is
difficult to predict with certainty, given existing data, when
exposures that are generally expected are likely to result in
significantly altered or abandoned behavioral patterns. Therefore, the
Navy's take estimates capture a wider range of impacts, including less
significant responses. Moreover, NMFS does not assume that each
instance of Level B harassment modeled by the Navy will have, or is
likely to have, an adverse impact on an individual's fitness. Rather,
NMFS considers the available scientific evidence to determine the
likely nature of the modeled behavioral responses and the potential
fitness consequences for affected individuals in its negligible impact
evaluation. Accordingly, we consider application of this Level B
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 (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 being proposed for authorization.
Estimates of Potential Marine Mammal Exposure
The Navy's acoustic impact analysis for marine mammals represents
an evolution that builds upon the analysis and methodology documented
in previous SURTASS LFA sonar NEPA efforts (DoN, 2001; 2007; 2012; and
2017), and includes updates of the most current acoustic thresholds and
methodology to assess auditory impacts (NMFS, 2018). A detailed
discussion of the acoustic impact analysis is provided in Appendix B of
the SURTASS DSEIS/SOEIS, but is summarized here.
Using the Acoustic Integration Model (AIM), the Navy modeled 15
representative model areas in the central and western North Pacific and
eastern Indian Oceans, representing the acoustic regimes and marine
mammal species that may be encountered during SURTASS LFA sonar
training and testing activities. Modeling was
[[Page 7223]]
conducted for one 24-hour period in each of the four seasons in each
model area. To predict acoustic exposure, the LFA sonar ship was
simulated traveling in a triangular pattern at a speed of 4 knots (kt)
(7.4 kilometers per hour (kph), for eight hours in each leg of the
triangle. The duration of the LFA sonar transmission was modeled as 24
hours, with a signal duration of 60 seconds and a duty cycle of 10
percent (i.e., the source transmitted for 60 seconds every 10 minutes
for 24 hours, which equates to 2.4 active transmission hours and is
representative of average actual transmission times based on the past
17 years of SURTASS LFA sonar activities).
The acoustic field around the LFA sonar source was predicted by the
Navy standard parabolic equation propagation model using the defined
LFA sonar operating parameters. Each marine mammal species potentially
occurring in a model area in each season was simulated by creating
animats (simulated animals) programmed with behavioral values
describing their dive and movement patterns. AIM then integrates the
acoustic field created from the underwater transmission of LFA sonar
with the three-dimensional (3D) movement of marine mammals to estimate
their potential for sonar exposure at each 30-second timestep within
the 24-hour modeling period. Thus, the output of AIM is the time
history of exposure for each animat.
The Navy assesses the potential impacts on marine mammals by
predicting the sound field that a given marine mammal species/stock
could be exposed to over time in a potential model area. This is a
multi-part process involving: (1) The ability to measure or estimate an
animal's location in space and time; (2) the ability to measure or
estimate the three-dimensional sound field at these times and
locations; (3) the integration of these two data sets into the acoustic
impact model to estimate the total acoustic exposure for each animal in
the modeled population; and (4) the conversion of the resultant
cumulative exposures for a modeled population into an estimate of the
risk of a potential injury (i.e., Level A harassment (PTS)), TTS, or
disruption of natural behavioral patterns (i.e., a take estimate for
Level B harassment).
To estimate the potential impacts for each marine mammal stock on
an annual basis, several calculation steps are required. First, the
potential impact for one LFA sonar transmission hour is calculated.
Second, the number of LFA sonar transmission hours that may occur in
each model area for each activity is determined. The third step is to
determine the number of model areas in which each stock may occur for
each activity, and the fourth step is to select the maximum per-hour
impact for each stock that may occur in the model areas for that
activity. The final step is to multiply the results of steps two,
three, and four to calculate the potential annual impacts per activity,
which are then summed across the stocks for a total potential impact
for all individual activities. The number of individual marine mammals
that may be taken over the seven-year period of the proposed SURTASS
LFA sonar training and testing activities was estimated by multiplying
the maximum number of instances of exposure for each species/stock
calculated annually for each of the two transmission scenarios (496
transmission hours in years 1-4 and 592 transmission hours in years 5-
7), and then adding these to calculate a total estimate. For example,
for the WNP blue whale, four years of 496 transmission hours (for years
1-4) resulted in 90 Level B harassment takes/year and three years of
592 transmission hours (for years 5-7) resulted in 123 Level B
harassment takes/year. Multiplying 90 takes/year by 4 years equals 360
Level B harassment takes for the 496 transmission hour scenario, and
multiplying 123 takes/year by 3 years equals 369 Level B harassment
takes for the 592 transmission hour scenario. The final step is adding
the totals for the two transmission scenarios to arrive at a total (360
+ 369 = 729 Level B harassment takes over the 7-year period for WNP
blue whales). For additional detail on modelling and take estimation,
please refer to Chapter 6.6 (Quantitative Impact Analysis for Marine
Mammals) of the Navy's application and Appendix B of the SURTASS DSEIS/
SOEIS.
With the implementation of the three-part monitoring programs
(visual, passive acoustic, and HF/M3 monitoring, as discussed below),
NMFS and the Navy do not expect that marine mammals would be injured by
SURTASS LFA sonar because a marine mammal is likely to be detected and
active transmissions suspended or delayed to avoid injurious exposure.
The probability of detection of a marine mammal by the HF/M3 system
within the LFA sonar mitigation zone approaches 100 percent over the
course of multiple pings (see the 2001 FOEIS/EIS, Subchapters 2.3.2.2
and 4.2.7.1 for the HF/M3 sonar testing results as well as section
5.4.3 of the SURTASS 2018 DSEIS/SOEIS for a summary of the
effectiveness of the HF/M3 system). Quantitatively, modeling output
shows zero takes by Level A harassment for all marine mammal stocks in
all representative mission areas with mitigation applied. As noted
above, all hearing groups of marine mammals except LF cetaceans would
need to be within 22 ft (7 m) of the LFA sonar source for an entire LFA
transmission (60 seconds), and a LF cetacean would need to be within
135 ft (41 m) for an entire LFA transmission to potentially experience
PTS. This is unlikely to occur, especially given the mitigation
measures in place and the Navy's proven effectiveness at detecting
marine mammals well outside of this range so that shut down measures
would be implemented well before marine mammals would be within these
ranges. Again, NMFS notes that over the course of the previous three
rulemakings from 2002 to 2017, and during the Navy's training and
testing activities during the NDE from 2017 to the present, there have
been no reported or known incidents of Level A harassment of any marine
mammal. This is due to the fact that it would be highly unlikely that a
marine mammal would remain close enough to the vessel to experience
Level A harassment (see discussion in Threshold Shift subsection of the
Potential Effects of the Specified Activity on Marine Mammals and their
Habitat section above), in combination with the Navy's highly effective
detection of marine mammals and shutting down SURTASS LFA sonar prior
to the animals entering the Level A harassment zone. Therefore, NMFS
does not propose to authorize any Level A takes for any marine mammal
species or stocks over the course of the 7-year regulations. Marine
mammals could experience TTS at farther distances, but would still need
to be within the shutdown distance for that to happen. The distances to
the TTS thresholds are less than 50 ft (15 m) for MF and HF cetaceans
and otariids; 216 ft (66 m) for phocids; and 1,354 ft (413 m) for LF
cetaceans if an animal were to remain at those distances for an entire
LFA sonar signal (60 sec). While it is likely that mitigation measures
would also avoid TTS, some small subset of the animals may also
experience TTS. Any TTS incurred would likely be of a low level and of
short duration because we do not expect animals to be exposed for long
durations close to the source.
Of note, the estimated number of Level B harassment takes does not
necessarily 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 B harassment threshold) that are anticipated
to occur over the seven-year period. Some individuals may
[[Page 7224]]
experience multiple instances of take (meaning over multiple days) over
the course of the year, while some members of a species or stock may
not experience take at all, which means that the number of individuals
taken is smaller than the total estimated takes. In other words, where
the instances of take exceed the number of individuals in the
population, repeated takes (on more than one day) of some individuals
are predicted. 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. However, because of the nature of the SURTASS LFA activities
(small number of continuously moving vessels spread over a very large
area), there are likely fewer repeated takes of the same individuals
than would be expected from other more localized or stationary
activities.
More detailed information for each of the steps to quantify take
estimates, as well as an illustrative example, are provided in section
6.6 of the Navy's application (Quantitative Impact Analysis for Marine
Mammals). A more thorough description of the impact analysis is also
provided in the Draft SEIS/SOEIS (DoN, 2018), specifically section
4.5.2.1.3, Marine Mammals (Quantitative Impact Analysis for Marine
Mammals subsection) and Appendix B (Marine Mammal Impact Analysis).
NMFS has reviewed this information and has accepted the Navy modeling
procedure and results. The total maximum potential impact on an annual
basis for years 1-4 and years 5-7 as well as the total overall takes
for the 7-year period covered by the proposed rulemaking are presented
in Table 18 below. These are considered conservative estimates because
they are based on the maximum potential impact to a stock across all
model areas in which an activity may occur. Therefore, if an activity
occurs in a different model area than the area where the maximum
potential impact was predicted, the actual potential impact may be less
than estimated. However, since the Navy cannot forecast where a
specific activity may be conducted this far in advance, this maximum
estimate provides the Navy with the flexibility to conduct its training
and testing activities across all modeled areas identified for each
activity.
Table 18--Maximum Total Annual MMPA Level B Harassment Proposed for Authorization for Years 1-4 and 5-7, and Total for the 7-Year Period of the Proposed
Rule by SURTASS LFA Sonar
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum annual Level B Maximum annual Level B
harassment, years 1-4 harassment, years 5-7 Total overall
---------------------------------------------------------------- Level B
Species Stock \1\ Percent Percent harassment for
Instances species or Instances species or 7-year period
stock stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
Antarctic minke whale..................... ANT......................... 0 0.00 0 0.00 0
Blue whale................................ CNP......................... 3 2.39 4 2.85 24
NIND........................ 0 0.00 1 0.00 3
WNP......................... 90 0.90 123 1.14 729
SIND........................ 1 0.07 1 0.07 7
Bryde's whale............................. ECS......................... 14 10.28 19 14.13 113
Hawaii...................... 5 0.62 6 0.74 38
WNP......................... 378 1.94 437 2.26 2,823
NIND........................ 8 0.07 10 0.10 62
SIND........................ 7 0.05 9 0.07 55
Common minke whale........................ Hawaii...................... 572 2.30 682 2.74 4,334
IND......................... 1,271 0.43 1,748 0.59 10,328
WNP JW...................... 3 0.12 5 0.17 27
WNP OE...................... 2,127 8.59 2,404 9.71 15,720
YS.......................... 189 4.20 250 5.57 1,506
Fin whale................................. ECS......................... 9 1.80 12 2.47 72
Hawaii...................... 3 2.30 4 2.74 24
IND......................... 0 0.00 0 0.00 0
SIND........................ 22 0.05 30 0.07 178
WNP......................... 2,558 27.55 3,455 37.23 20,597
Humpback whale............................ CNP stock and Hawaii DPS.... 487 4.85 611 6.10 3,781
WAU stock and DPS........... 1 0.00 1 0.00 7
WNP stock and DPS........... 3,103 233.84 4,266 321.49 25,210
North Pacific right whale................. WNP......................... 89 9.57 122 13.15 722
Omura's whale............................. NIND........................ 8 0.07 10 0.10 62
SIND........................ 5 0.04 7 0.05 41
WNP......................... 14 0.81 16 0.95 104
Sei whale................................. Hawaii...................... 19 4.78 22 5.70 142
SIND........................ 0 0.00 0 0.00 0
NP.......................... 3,172 45.37 4,361 62.37 25,771
NIND........................ 4 0.04 5 0.05 31
Western North Pacific gray whale.......... WNP stock and Western DPS... 0 0.00 1 0.44 3
Baird's beaked whale...................... WNP......................... 2,747 48.26 3,777 66.36 22,319
Blainville's beaked whale................. Hawaii...................... 35 1.83 47 2.40 281
WNP......................... 269 3.30 311 3.82 2,009
IND......................... 47 0.27 65 0.37 383
Common bottlenose dolphin................. 4-Islands................... 5 2.48 6 2.96 38
Hawaii Island............... 0 0.00 0 0.00 0
Hawaii Pelagic.............. 95 0.41 114 0.49 722
IA.......................... 104 0.11 140 0.15 836
[[Page 7225]]
IND......................... 1,128 0.14 1,551 0.20 9,165
Japanese Coastal............ 1,686 47.94 1,789 50.86 12,111
Kauai/Niihau................ 13 7.16 16 8.55 100
Oahu........................ 38 5.17 46 6.17 290
WNP Northern Offshore....... 581 0.57 799 0.78 4,721
WNP Southern Offshore....... 2,726 6.63 3,063 7.45 20,093
WAU......................... 635 21.16 873 29.09 5,159
Common dolphin............................ IND......................... 52 0.00 72 0.00 424
WNP......................... 203,871 12.24 275,079 16.08 1,640,721
Cuvier's beaked whale..................... Hawaii...................... 22 3.03 26 3.62 166
IND......................... 231 0.85 317 1.17 1,875
SH.......................... 77 0.11 106 0.15 626
WNP......................... 6,946 7.78 8,980 10.04 54,724
Dall's porpoise........................... SOJ dalli type.............. 614 0.36 845 0.49 4,991
WNP dalli ecotype........... 22,056 13.62 30,327 18.72 179,205
WNP truei ecotype........... 487 0.28 670 0.39 3,958
Deraniyagala's beaked whale............... IND......................... 158 0.92 217 1.27 1,283
NP.......................... 190 0.77 222 0.91 1,426
Dwarf sperm whale......................... Hawaii...................... 655 3.72 782 4.44 4,966
IND......................... 3 0.05 4 0.07 24
WNP......................... 486 0.14 635 0.18 3,849
False killer whale........................ Hawaii Pelagic.............. 58 3.72 69 4.44 439
IA.......................... 252 2.59 341 3.51 2,031
IND......................... 12 0.01 16 0.00 96
Main Hawaiian Islands 1 0.41 1 0.49 7
Insular stock and DPS.
Northwestern Hawaiian 0 0.00 0 0.00 0
Islands.
WNP......................... 1,350 8.15 1,596 9.63 10,188
Fraser's dolphin.......................... CNP......................... 546 3.24 686 4.06 4,242
Hawaii...................... 1,944 3.79 2,320 4.52 14,736
IND......................... 93 0.05 128 0.07 756
WNP......................... 2,287 1.16 2,559 1.29 16,825
Ginkgo-toothed beaked whale............... IND......................... 12 0.07 16 0.10 96
NP.......................... 283 1.21 329 1.40 2,119
Harbor porpoise........................... WNP......................... 366 1.17 503 1.61 2,973
Hubbs' beaked whale....................... NP.......................... 26 0.11 36 0.15 212
Indo-Pacific bottlenose dolphin........... IND......................... 11 0.14 16 0.20 92
Killer whale.............................. Hawaii...................... 6 4.41 8 5.26 48
IND......................... 397 3.15 546 4.33 3,226
WNP......................... 10,470 85.37 14,387 117.31 85,041
Kogia spp.\2\............................. WNP......................... 1,317 0.31 1,494 0.35 9,750
Longman's beaked whale.................... Hawaii...................... 739 5.01 882 11.59 5,602
IND......................... 325 1.92 447 2.64 2,641
WNP......................... 471 6.14 574 7.50 3,606
Melon-headed whale........................ Hawaiian Islands............ 181 2.07 216 2.47 1,372
IND......................... 402 0.64 552 0.88 3,264
Kohala Resident............. 9 0.41 11 0.49 69
WNP......................... 1,605 2.87 1,823 3.27 11,889
Mesoplodon spp.\2\........................ WNP......................... 10 0.05 14 0.07 82
Northern right whale dolphin.............. NP.......................... 0 0.00 0 0.00 0
Pacific white-sided dolphin............... NP.......................... 9,530 1.05 12,890 1.41 76,790
Pantropical spotted dolphin............... 4-Islands................... 32 14.40 38 17.18 242
Hawaii Island............... 23 10.26 27 12.25 173
Hawaiian Pelagic............ 297 0.55 355 0.66 2,253
IND......................... 311 0.05 428 0.07 2,528
Oahu........................ 23 10.54 28 12.58 176
WNP......................... 5,105 3.95 5,883 4.53 38,069
Pygmy killer whale........................ Hawaii...................... 393 3.72 469 4.44 2,979
IND......................... 60 0.27 82 0.37 486
WNP......................... 901 2.87 1,035 3.30 6,709
Pygmy sperm whale......................... Hawaii...................... 266 3.72 318 4.44 2,018
IND......................... 0 0.00 0 0.00 0
[[Page 7226]]
WNP......................... 203 0.07 265 0.09 1,607
Risso's dolphin........................... Hawaii...................... 414 3.58 494 4.28 3,138
IA.......................... 1,045 0.70 1,374 0.92 8,302
WNP......................... 4,347 3.07 4,914 3.47 32,130
IND......................... 4,621 1.01 6,354 1.39 37,546
Rough-toothed dolphin..................... Hawaii...................... 213 0.28 254 0.33 1,614
IND......................... 41 0.00 57 0.00 335
WNP......................... 1,439 28.74 1,732 34.56 10,952
Short-finned pilot whale.................. Hawaii...................... 396 2.00 473 2.38 3,003
IND......................... 1,526 0.59 2,098 0.81 12,398
WNP Northern Ecotype........ 525 2.52 721 3.47 4,263
WNP Southern Ecotype........ 5,683 18.03 6,303 19.99 41,641
Southern bottlenose whale................. IND......................... 22 0.00 31 0.00 181
Spade-toothed beaked whale................ IND......................... 16 0.09 22 0.12 130
Sperm whale............................... Hawaii...................... 106 2.34 126 2.80 802
NIND........................ 33 0.14 46 0.20 270
NP.......................... 1,429 1.28 1,855 1.68 11,281
SIND........................ 16 0.07 22 0.10 130
Spinner dolphin........................... Hawaii Island............... 1 0.21 1 0.25 7
Hawaii Pelagic.............. 192 5.72 229 6.82 1,455
IND......................... 240 0.05 330 0.07 1,950
Kauai/Niihau................ 83 13.85 99 16.53 629
Kure/Midway Atoll........... 0 0.00 0 0.00 0
Oahu/4-Islands.............. 20 2.88 24 6.66 152
Pearl and Hermes Reef....... 0 0.00 0 0.00 0
WNP......................... 574 0.00 721 0.00 4,459
Stejneger's beaked whale.................. WNP......................... 201 2.49 276 3.42 1,632
Striped dolphin........................... Hawaii...................... 269 0.41 321 0.49 2,039
IND......................... 5,059 0.75 6,957 1.03 41,107
Japanese Coastal............ 3,366 17.18 3,571 18.23 24,177
WNP Northern Offshore....... 267 0.07 367 0.10 2,169
WNP Southern Offshore....... 3,282 6.28 3,729 7.13 24,315
Hawaiian monk seal........................ Hawaii...................... 10 0.69 13 0.91 79
Northern fur seal......................... Western Pacific............. 8,475 1.71 11,653 2.35 68,859
Ribbon seal............................... NP.......................... 15,705 4.30 21,595 5.92 127,605
Spotted seal.............................. Alaska stock/Bering Sea DPS. 80,722 17.53 110,993 24.10 655,867
Southern stock and DPS...... 0 0.00 1 0.05 3
Steller sea lion.......................... Western/Asian stock, Western 2 0.00 3 0.00 17
DPS.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ANT=Antarctic; CNP=Central North Pacific; NP=North Pacific; NIND=Northern Indian; SIND=Southern Indian; IND=Indian; WNP=Western North Pacific;
ECS=East China Sea; WP=Western Pacific; SOJ=Sea of Japan; IA=Inshore Archipelago; WAU=Western Australia; YS=Yellow Sea; OE=Offshore Japan;
OW=Nearshore Japan; JW=Sea of Japan/Minke; JE=Pacific coast of Japan; SH=Southern Hemisphere; DPS=distinct population segment.
\2\ Kogia spp.: Pygmy and dwarf sperm whales are difficult to distinguish at sea, and abundance estimates are pooled for Kogia spp. in Modeled Areas 1,
2, 3, 5, 6, and 7 (reported as pooled in Ferguson and Barlow, 2001 and 2003, and pooled). Mesoplodon spp.: No methods are available to distinguish
between the species of Mesoplodon beaked whales in the WNP stocks (Blainville's beaked whale (M. densirostris), Perrin's beaked whale (M. perrini),
Lesser beaked whale (M. peruvianus), Stejneger's beaked whale (M. stejnegeri), Gingko-toothed beaked whale (M. gingkodens), and Hubbs' beaked whale
(M. carlhubbsi)) when observed during at-sea surveys (Carretta et al., 2018). As reported in Ferguson and Barlow, 2001 and 2003, data on these species
were pooled. These six species are managed as one unit.
Proposed Mitigation
Under section 101(a)(5)(A) of the MMPA, NMFS must set forth the
``permissible methods of taking pursuant to such activity, and other
means of effecting the least practicable adverse impact on such species
or stock and its habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance, and on the
availability of such species or stock for subsistence uses''
(hereinafter referred to as ``LPAI'' or ``least practicable adverse
impact''). NMFS does not have a regulatory definition for least
practicable adverse impact. The NDAA for FY 2004 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.''
Least Practicable Adverse Impact Standard
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] satisfies] the statutory `least
practicable adverse impact' requirement
[[Page 7227]]
with a `negligible impact' finding.'' More recently, expressing similar
concerns in a challenge to the 2012 SURTASS LFA incidental take rule
(77 FR 50290), 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, and expands upon,
previous rules we have issued, such as the Navy Gulf of Alaska rule (82
FR 19530; April 27, 2017); the Navy Atlantic Fleet Testing and Training
rule (83 FR 57076; November 14, 2018); and the Navy Hawaii-Southern
California Training and Testing rule (83 FR 66846; December 27, 2018).
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 USFWS' 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 \1\ and, therefore are considered in evaluating population
level impacts.
---------------------------------------------------------------------------
\1\ A growth rate can be positive, negative, or flat.
---------------------------------------------------------------------------
As we stated in the preamble to the final rule for the 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
such species or stock and its 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.\2\
---------------------------------------------------------------------------
\2\ For purposes of this discussion, we omit reference to the
language in the standard for least practicable adverse impact that
says we also must mitigate for subsistence impacts because they are
not at issue in this regulation.
---------------------------------------------------------------------------
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). 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 (16 U.S.C. 1362(11)). 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, the term ``stock'' in the MMPA is interchangeable with the
statutory term ``population stock.'' (16 U.S.C. 1362(11). 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's statutory
findings for enacting the MMPA, nearly all of which are most applicable
at the species or stock (i.e., population) level. See 16 U.S.C. 1361
(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 affect the least practicable amount of adverse
impact upon the affected species or stock.
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 and their habitat. 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, we reiterate that 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
[[Page 7228]]
standard is concerned solely with conclusions about the impact of an
activity on annual rates of recruitment and survival.\3\
---------------------------------------------------------------------------
\3\ 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).
---------------------------------------------------------------------------
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.'' Id. 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.
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 a
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 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. 16 U.S.C. 1371(a)(5)(A)(iii).
While the language of the least practicable adverse impact standard
calls for minimizing impacts to affected species or stocks and their
habitats, 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. 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
that we had not previously considered, becomes available and
necessitates 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 firmly established biological importance).
Regarding practicability, a measure might involve restrictions in an
area or time that impede the Navy's ability to certify a strike group
(higher impact on mission effectiveness), or it could mean delaying a
small in-port training event by 30 minutes to avoid exposure of a
marine mammal to injurious levels of sound (lower impact). A
responsible evaluation of ``least practicable adverse impact'' will
consider the factors along these realistic scales. Accordingly, the
greater the likelihood that a measure will contribute to reducing the
probability or
[[Page 7229]]
severity of adverse impacts to the species or stock or their 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.\4\ 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.
---------------------------------------------------------------------------
\4\ 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 those measures, taking into account the
MMPA's directive that we 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 16 U.S.C. 1362(20)); the affected
species or stock is a small, resident population; or the stock is
involved in a UME or has other known vulnerabilities, such as
recovering from an oil spill.
Habitat mitigation, particularly as it relates to rookeries, mating
grounds, and areas of similar significance, is also relevant to
achieving the standard and can include measures such as reducing
impacts of the activity on known prey utilized in the activity area or
reducing impacts on physical habitat. As with species- or stock-related
mitigation, the emphasis given to a measure's ability to reduce impacts
on a species or stock's habitat considers the degree, likelihood, and
context of the anticipated reduction of impacts to habitat. Because
habitat value is informed by marine mammal presence and use, in some
cases there may be overlap in measures for the species or stock and for
use of habitat.
We consider available information indicating the likelihood of any
measure to accomplish its objective. If evidence shows that a measure
has not typically been effective nor successful, then either that
measure should be modified or the potential value of the measure to
reduce effects should be lowered.
2. Practicability. Factors considered may include cost, impact on
activities, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity (16 U.S.C.
1371(a)(5)(A)(iii)).
Proposed Mitigation Measures
As with other rulemakings for SURTASS LFA sonar, our consideration
of mitigation under the LPAI standard was conducted at scales that take
into account the entire rulemaking period and geographic scope of
potential areas of SURTASS LFA sonar activities and the types of
impacts that could occur under the rule. NMFS reviewed the proposed
activities and the proposed mitigation measures as described in the
Navy's LOA application and the measures added by NMFS to determine if
they would satisfy the standard of LPAI on marine mammal species or
stock(s) and their habitat. As described below, and in the SURTASS
DSEIS/DOEIS (DoD, 2018), NMFS has preliminarily determined that the
following mitigation measures would satisfy the LPAI standard:
(1) 2,000-yard LFA sonar mitigation and buffer zone--LFA sonar
training and testing transmissions will be suspended if the Navy
detects marine mammals within a distance of 2,000 yards (1.8 km; 1.1
mi; 1.0 nmi) of the LFA sonar source, which encompasses both the
approximately 1-km distance of the 180 dB received level mitigation
zone and an additional buffer, by any of the following detection
methods:
(a) Visual monitoring;
(b) Passive acoustic monitoring; and
(c) Active acoustic monitoring.
(2) Geographic restrictions--LFA sonar training and testing will be
conducted such that:
(a) The received level of SURTASS LFA sonar transmissions during
training and testing events will not exceed 180 dB within 1 km seaward
of any OBIA boundary, as presented in the Final Rule, during the
indicated periods of biological importance;
(b) the received level of SURTASS LFA sonar transmissions will not
exceed 180 dB within the Coastal Standoff Zone (22 km (12 nmi) from any
land);
(c) no activities with the SURTASS LFA sonar system will occur
within territorial seas of foreign nations, which are areas up to 12
nmi from shore, depending on the distance that individual nations
claim; and
(d) no activities with the SURTASS LFA sonar system will occur
within Hawaii state waters (out to 3 nmi) or in the waters of Penguin
Bank and ensonification of Hawaii state waters will not be at levels
above 145 dB.
Below, we discuss the proposed mitigation measures as agreed upon
by the Navy and NMFS. Any mitigation, monitoring, or reporting measures
finalized following consideration of public comments would be required
by the final regulations and/or associated LOA. For additional details
regarding the Navy's mitigation measures, please also see Chapter 5 in
the SURTASS 2018 DSEIS/DOEIS.
[[Page 7230]]
Proposed 2,000-Yard Mitigation Zone (Re-Evaluation of the 180-dB re 1
[mu]Pa (RMS) Zone)
The Navy has requested, and NMFS is proposing to include in this
rule, a single, fixed 2,000-yard (yd) (0.99 nmi/1,829 m/1.83 km)
mitigation zone rather than a combined mitigation and buffer zone
(based on real-time propagation modeling) of nominally 1.08 nmi (2 km),
which has been required in past rules. This modification will
standardize and simplify Navy mitigation and monitoring implementation
and includes consideration of updated information on marine mammal
injury thresholds. The 180-dB re1[micro]Pa (RMS) threshold for the
onset of potential injury has been used in the impact assessment for
SURTASS LFA sonar since 2001, and the isopleth associated with that
threshold has also previously informed the development of mitigation.
However, NMFS' 2018 Acoustic Technical Guidance reflects the current
state of scientific knowledge regarding the potential impacts of sound
on marine mammal hearing. It specifies auditory weighted
(SELcum) values for the onset of PTS (onset of injury) based
on marine mammal hearing groups. The NMFS 2018 Acoustic Technical
Guidance categorizes marine mammals into five generalized hearing
groups with defined hearing ranges and presents the auditory weighting
functions developed for each of these hearing groups, reflecting the
best available data on hearing, impacts of sound on hearing, and data
on equal latency.
When estimating the onset of injury (PTS), NMFS' Acoustic Technical
Guidance defines weighted thresholds as sound exposure levels (SEL). As
noted previously in the Metrics Used in this Document section, the new
threshold and its associated metric incorporate a duration component,
which means that it is not directly comparable to the previous 180-dB
re1[micro]Pa (RMS) threshold. To determine what the SEL for each
hearing group would be when exposed to a 60-second (the nominal time of
an LFA sonar transmission, or one ping), 300 Hz (the center frequency
in the possible transmission range of 100-500 Hz) SURTASS LFA sonar
transmission, the appropriate auditory weighting function must be
applied to account for each of the hearing group's sensitivity. Again,
although direct comparisons are difficult, when a 60-second exposure is
considered, applying the auditory weighting functions results in the
thresholds increasing by approximately 1.5; 46; 56; 15; and 20 dB for
the LF, MF, HF, PW, and OW hearing groups, respectively, above the
baseline. Consequently, if mitigation is tied to preventing the same
type of impact, the distance at which SURTASS LFA sonar transmissions
should be mitigated for marine mammals would be the distance associated
with LF cetaceans, as the mitigation range would be the greatest for
this hearing group. Any mitigation measure developed for LF cetaceans
based on PTS onset would be highly conservative for any other marine
mammals potentially exposed to SURTASS LFA sonar transmissions.
Applying the duration of a single ping of SURTASS LFA sonar (60
seconds) would result in 17.8 dB being subtracted from the unweighted
SELcum value of 200.5 dB for LF cetaceans, for an SPL of
182.7 dB re1[micro]Pa (RMS). The distance to this isopleth would be
slightly smaller than that associated with the previously used 180 dB
re1[micro]Pa (RMS) isopleth. If an LF cetacean was exposed to two full
pings of SURTASS LFA sonar, the resulting SPL would be 179.7 dB
re1[micro]Pa (RMS), which is very close to the 180 dB re1[micro]Pa
(RMS) RL level, on which previous mitigation measures were based. This
exposure is unlikely, as a marine mammal would have to be close to the
LFA sonar array for an extended period (approximately 20 minutes) to
experience two full pings. Although this is an unlikely scenario, the
Navy proposes a mitigation zone that is basically equivalent to the
previous zone based on 180 dB re1[micro]Pa (RMS) RL as the current
mitigation zone for SURTASS LFA sonar training and testing activities
in this rule, as described below.
In previous rules, prior to commencing and during SURTASS LFA sonar
training and testing transmissions, the Navy determined (in real time)
the propagation of LFA sonar signals in the ocean and the distance from
the SURTASS LFA sonar source to the 180-dB isopleth (See Description of
Real-Time SURTASS LFA Sonar Sound Field Modeling section of the
application). The 180-dB isopleth defined the extent of the LFA sonar
mitigation zone for marine mammals around the surveillance vessel. If a
marine mammal entered the LFA sonar mitigation zone (or the 1-km buffer
previously required by NMFS, as described below), the Navy implemented
a suspension of SURTASS LFA sonar transmissions. This measure was
included in prior rules to reduce or alleviate the likelihood that
marine mammals would be exposed to levels of sound that may result in
injury (PTS). However, due to the updated criteria in NMFS' 2018
Acoustic Technical Guidance (NMFS 2018), this 180-dB mitigation zone
would not only preclude PTS, but almost all TTS and more severe
behavioral reactions as well. While not an expansion of the mitigation,
the mitigation is now considered more effective at reducing PTS and TTS
compared to prior authorizations for SURTASS LFA sonar.
The Navy modeling of the sound field in near-real time conditions
provided the information necessary to calculate the mitigation zone for
which delay or suspension of LFA sonar transmissions would occur.
Acoustic model updates were nominally made every 12 hrs, or as
meteorological or oceanographic conditions change. If a marine mammal
entered the calculated threshold distance (plus its associated buffer
distance), the sonar operator notified the senior military member in
charge, who would order the delay or suspension of transmissions. If it
were predicted that the SPL threshold distances would change within the
next 12-hr period, the senior military member in charge would also be
notified in order to take the necessary action to ensure that the sound
field criteria would not be exceeded.
As an added protective measure, NMFS previously required the Navy
to include a ``buffer zone'' that extends an additional 1 km (0.62 mi;
0.54 nm) beyond the Navy's proposed 180-dB isopleth LFA sonar
mitigation zone. This buffer typically coincides with the full
detection range of the HF/M3 active sonar for mitigation monitoring
(approximately 2 to 2.5 km; 1.2 to 1.5 mi; 1.1 to 1.3 nmi). Thus,
implementation of this additional 1 km buffer zone increased the
shutdown zone around the LFA sonar array and vessel and, given the
highly effective monitoring capabilities (described below), ensured
that no marine mammals are exposed to an SPL greater than approximately
174 dB re: 1 [micro]Pa. In past applications, the Navy has noted that
this additional mitigation is practicable and the Navy has implemented
this measure in previous authorizations. In addition, as noted above
for the 180-dB mitigation zone, this buffer mitigation is more
effective at reducing a broader range of impacts compared to prior
authorizations due to the updated criteria in NMFS' Acoustic Technical
Guidance (NMFS, 2018). The proposed 2,000 yd (1.83 km) single fixed
mitigation/buffer zone would cover virtually all of the previous
combined mitigation/buffer zone of nominally 1.08 nmi (2 km), since the
difference between 2,000 yd and 2 km is only about 187 yd (or 0.09 nmi
(167 m)). Likewise, the difference in the sound field of the combined
mitigation/
[[Page 7231]]
buffer zones of 2,000 yd (1.83 km) versus 1.08 nmi (2,187 yd; 2 km)
would also be negligible. At 2,000 yd (1.83 km), modeling shows that
the sound field would be about 174.75 dB while at 1.08 nmi (2 km), the
sound field would be 173.98 dB, which is a difference of only 0.77 dB.
This very slight sound field difference would not be perceptible to a
marine mammal.
In summary, Navy requested, and NMFS is proposing to include, a
single, fixed, combined mitigation/buffer zone for SURTASS LFA sonar
training and testing activities to standardize and simplify
implementation of this monitoring requirement using standard Navy
metrics (yards not meters). This measure will continue to ensure
protection to marine mammals in all acoustic environments, even in the
rare event of a strong acoustic duct in which the volume of water
ensonified to 180 dB could be somewhat greater than 0.54 nmi (1 km)
(DoN, 2001). With the combined mitigation/buffer zone of 2,000 yd (1.83
km), there is no potential for animals to be exposed to received levels
greater than 180 dB rms, or levels above the new injury thresholds
identified in NMFS acoustic thresholds, and, therefore, marine mammals
are protected from both acoustic injury and more severe occurrences of
Level B harassment.
Visual Mitigation Monitoring
Visual monitoring consists of daytime observations for marine
mammals from the bridge of SURTASS LFA sonar vessels by lookouts
(personnel trained in detecting and identifying marine mammals). Navy
shipboard lookouts are highly qualified and experienced observers of
the marine environment. Their operational duties require that they
report all objects sighted on the water surface to the senior military
member in charge (e.g., trash, a periscope, marine mammals, sea
turtles) and all disturbances (e.g., surface disturbance,
discoloration) that may be indicative of a threat to the vessel and its
crew. The objective of visual mitigation monitoring is to maintain
location, distance, and movement information about marine mammals
observed to ensure that none approach close enough to enter the 2,000-
yard LFA mitigation/buffer zone.
Daylight is defined as 30 min before sunrise until 30 min after
sunset. Visual monitoring would begin 30 min before sunrise or 30 min
before the Navy deploys the SURTASS LFA sonar array. Lookouts will
continue to monitor the area until 30 min after sunset or until
recovery of the SURTASS LFA sonar array.
The lookouts will maintain a topside watch and marine mammal
observation log during daytime activities that employ SURTASS LFA sonar
in the active mode. These trained monitoring personnel maintain a
topside watch and scan the water's surface around the vessel
systematically with standard binoculars (7x) and with the naked eye. If
the lookout sights a possible marine mammal, the lookout will use big-
eye binoculars (25x) to confirm the sighting and potentially identify
the marine mammal species. Lookouts will enter numbers and
identification of marine mammals sighted into the log, as well as any
unusual behavior. A designated ship's officer will monitor the conduct
of the visual watches and periodically review the log entries.
If a lookout observes a marine mammal outside of the 2,000-yard LFA
mitigation/buffer zone, the lookout will notify the senior military
member in charge of the watch. The senior military member in charge
shall then notify the HF/M3 active sonar operator to determine the
range and projected track of the marine mammal. If the HF/M3 sonar
operator or the lookout determines that the marine mammal will pass
within the 2,000-yard LFA mitigation/buffer zone, the senior military
member in charge shall order the delay or suspension of SURTASS LFA
sonar training and testing transmissions when the animal enters the
2,000-yard LFA mitigation/buffer zone to prevent Level A harassment as
well as reduce the potential for TTS and more severe behavioral
responses.
If a lookout observes a marine mammal anywhere within the 2,000-
yard LFA mitigation/buffer zone (required by NMFS), the senior military
member in charge would be notified so that the LFA sonar training and
testing transmissions would be immediately shut down or suspended. The
lookout will enter his/her observations about sighted marine mammals
into the log: Date/time; vessel name; geographic coordinates/position;
type and number of marine mammals observed; assessment basis (i.e.,
observed injury or behavioral response); bearing from vessel; whether
activities were delayed, suspended, or terminated; and relevant
narrative information.
Marine mammal biologists who are qualified in conducting at-sea
marine mammal visual monitoring from surface vessels will train and
qualify designated ship personnel to conduct at-sea visual monitoring.
This training may be accomplished either in-person or via video
training.
Passive Acoustic Mitigation Monitoring
For the second of the three-part mitigation monitoring measures,
the Navy will conduct passive acoustic monitoring using the SURTASS
towed horizontal line array to detect vocalizing marine mammals as an
indicator of their presence. This system serves to augment the visual
and active sonar detection systems, and is deployed and operated at all
times in which the LFA sonar system could be utilized. If a passive
acoustic technician detects a vocalizing marine mammal that may be
potentially affected by SURTASS LFA sonar prior to or during
transmissions, the technician will notify the senior military member in
charge who will immediately alert the HF/M3 active sonar operators and
the lookouts. The senior military member in charge will order the delay
or suspension of SURTASS LFA sonar transmissions when the animal enters
the 2,000-yard LFA mitigation/buffer zone as detected by either the HF/
M3 sonar operator or the lookouts. The passive acoustic technician will
record all contacts of marine mammals into a log.
Active Acoustic Mitigation Monitoring
Active acoustic monitoring uses the high-frequency marine mammal
monitoring (HF/M3) sonar to detect, locate, and track marine mammals
that could pass close enough to the SURTASS LFA sonar array to enter
the 2,000-yard LFA sonar mitigation/buffer zone. HF/M3 acoustic
monitoring may be used at all times of the day or night and begins 30
min before the first SURTASS LFA sonar transmission of a given training
or testing activity is scheduled to commence and continues until the
Navy terminates LFA sonar transmissions.
If the HF/M3 sonar operator detects a marine mammal contact outside
the 2,000-yard LFA sonar mitigation/buffer zone, the HF/M3 sonar
operator shall determine the range and projected track of the marine
mammal. If the operator determines that the marine mammal will pass
within the 2,000-yard LFA sonar mitigation/buffer zone, he/she shall
notify the senior military member in charge. The senior military member
in charge then immediately orders the delay or suspension of training
and testing transmissions when the animal is predicted to enter the
2,000-yard LFA sonar mitigation/buffer zone.
If the HF/M3 sonar operator detects a marine mammal within the
2,000-yard LFA mitigation/buffer zone, he/she shall notify the senior
military member in charge who will immediately order the delay or
suspension of training and
[[Page 7232]]
testing transmissions. The HF/M3 sonar operator will record all
contacts of marine mammals into the log.
Prior to full-power operations of the HF/M3 active sonar during
SURTASS LFA sonar training and testing activities, the Navy will ramp
up the HF/M3 sonar power level over a period of 5 min from the source
level of 180 dB re 1 [mu]Pa at 1 m in 10-dB increments until the HF/M3
system attains full power (if required) to ensure that there are no
inadvertent exposures of marine mammals to received levels greater than
180 dB re 1 [mu]Pa from the HF/M3 sonar. The Navy will not increase the
HF/M3 sonar source level if any of the three monitoring methods detect
a marine mammal during ramp-up. Ramp-up of the HF/M3 active sonar may
continue once marine mammals are no longer detected by any of the three
monitoring methods.
In situations where the HF/M3 sonar system has been powered down
for more than 2 min during a training and testing event, the Navy will
ramp up the HF/M3 sonar power level over a period of 5 min from the
source level of 180 dB re 1 [mu]Pa at 1 m in 10-dB increments until the
system attains full power.
NMFS' Additional 1-km Buffer Zone Around OBIAs
Similar to the previously-required 1-km buffer around the LFA Sonar
Mitigation Zone, NMFS is proposing to require the Navy to include a
``buffer zone'' that extends an additional 1 km (0.62 mi; 0.54 nm)
beyond the seaward boundary of any OBIA (discussed in ``Geographic
Restrictions'' section immediately below). The Navy has noted that this
additional mitigation is practicable in past applications and has
implemented this measure in previous authorizations. In addition, as
noted above for the 180-dB mitigation zone, this 1-km buffer mitigation
is more effective at reducing a broader range of impacts compared to
prior authorizations due to the updated criteria in NMFS' Acoustic
Technical Guidance (NMFS, 2018).
Geographic Restrictions
As noted above, the Navy will implement geographic restrictions for
SURTASS LFA sonar training and testing activities that entail
restricting SURTASS LFA sonar activities within these designated areas
such that the SURTASS LFA sonar-generated sound field will not exceed
180 dB re: 1 [micro]Pa (RL): (1) Within a 1-km seaward buffer of any
finalized OBIAs for marine mammals, as required by NMFS; (2) observing
a coastal standoff range restricting SURTASS LFA sonar training and
testing activities such that the sound field will not exceed 180 dB re:
1[micro]Pa (RL) within 22 km (14 mi; 12 nmi) of any emergent land,
including islands; (3) the Navy will not conduct SURTASS LFA sonar
training and testing activities within the territorial seas of any
foreign nation (distance ranging from 0 to 12 km, depending on distance
claimed); and (4) the Navy will not operate SURTASS LFA sonar in Hawaii
state waters (out to 3 nmi) or in waters of Penguin Bank to the 600-ft
(183-m) isobath, and will ensure Hawaii state waters are not ensonified
above 145 dB.
As with previous rulemakings for SURTASS LFA sonar, this rulemaking
contains a consideration of geographic restrictions, including OBIAs.
However, whereas the Navy previously considered SURTASS LFA sonar
activities worldwide, they have narrowed the geographic scope of their
current application to reflect only those areas of the world's oceans
where the Navy anticipates conducting covered SURTASS LFA sonar
activities (i.e., training and testing in the central and western North
Pacific and eastern Indian Oceans). Therefore, consideration of
geographical restrictions is also limited to those areas of the world's
oceans where the Navy anticipates conducting covered SURTASS LFA sonar
activities, as discussed in more detail below.
Offshore Biologically Important Areas (Background)
Given the unique operational characteristics of SURTASS LFA sonar,
Navy and NMFS developed the concept of geographical restrictions for
SURTASS LFA sonar in the SURTASS LFA Sonar FOEIS/EIS (DoN, 2001) to
include: Delineating a 12 nmi coastal standoff zone where received
levels from SURTASS LFA sonar could not exceed 180 dB, and designating
OBIAs, where warranted, for areas beyond this coastal standoff zone,
wherein received levels could not exceed 180 dB. The coastal standoff
and OBIAs are intended to reduce the likelihood and/or degree of
impacts on affected marine mammal species or stocks. As noted in the
2012 Final Rule (77 FR 50290; August 20, 2012), over 80 percent of the
existing and potential marine protected areas reviewed were within 12
nmi from a coastline, indicating the effectiveness of the coastal
standoff as one of the primary mitigation measures for reducing
potential impacts to marine mammals. OBIAs expand upon this protection
by avoiding or minimizing impacts in areas beyond the coastal standoff
distance where marine mammals are known to engage in specific behaviors
that may lead to more severe impacts if interrupted; known to
congregate in higher densities; and/or known to have a limited range
and small abundance that creates more vulnerability for the stock as a
whole. These criteria are important when determining whether mitigation
would be likely to reduce the probability or severity of effects to
individuals that would translate to minimization of impacts at the
population level under the LPAI standard. Limiting LFA sonar activities
in these important areas is expected to limit the likelihood and/or
degree of species or stock effects by minimizing the chances that the
activity will result in detrimental energetic effects to individuals
(such as those that could occur in known feeding areas) or direct
interference in breeding or mother/young interactions (such as those
that could occur in reproductive or nursing areas) that could result in
reductions in reproductive success or survivorship.
Three OBIAs were identified in the 2001 FOEIS/EIS: 200 m isobaths
of the east coast of North America; Costa Rica Dome; and Antarctic
Convergence Zone. In 2007, the Navy published a supplemental FEIS/FOEIS
that designated six new OBIAs in addition to the three OBIAs that were
designated in the 2001 FEIS/FOEIS. The criteria for identifying OBIAs
in the 2001 and 2007 rules were originally defined in the 2001 SURTASS
LFA Sonar FOEIS/EIS (Subchapter 2.3.2.1) as areas of the world's oceans
outside of the geographic stand-off distance (greater than 22 km (12
nmi)) from a coastline (including islands) where marine animals of
concern (those animals listed under the ESA and/or marine mammals)
carry out biologically important activities, including migration,
foraging, breeding, and calving.
For the 2012 rule, the Deputy Assistant Secretary of the Navy for
Environment (DASN(E)) determined that the purpose of NEPA and E.O.
12114 would be furthered by the preparation of an additional
supplemental analysis related to the employment of SURTASS LFA sonar.
Accordingly, the DASN(E) directed that an SEIS/SOEIS (among other
things) provide further analysis of potential additional OBIAs in
regions of the world where the Navy intended to use the SURTASS LFA
sonar systems.
In parallel, for the 2012 rule, NMFS, with Navy input, developed a
new process and screening criteria for determining an area's
eligibility to be considered as an OBIA nominee for marine mammals.
Those screening criteria were: (1) Areas with: (a) High
[[Page 7233]]
densities of marine mammals; or (b) Known/defined breeding/calving
grounds, foraging grounds, migration routes; or (c) Small, distinct
populations of marine mammals with limited distributions; and (2) Areas
that are outside of the coastal standoff distance and within potential
operational areas for SURTASS LFA (i.e., greater than 22 km (13.6 mi;
12 nmi) from any shoreline and not in polar regions).
For the 2012 FSEIS/SOEIS and 2012 rule, NMFS also developed and
implemented a robust, systematic screening process for reviewing
existing and potential marine protected areas against the OBIA
criteria, based on the World Database on Protected Areas (WDPA, 2009),
Hoyt (2005), and prior SURTASS LFA sonar OBIAs. This process produced a
preliminary list of 403 OBIA nominees. As noted above, and stated in
the 2012 Final Rule (77 FR 50290; August 20, 2012), the vast majority
of the areas reviewed as potential OBIAs were within 12 nmi from a
coastline and therefore already afforded protection due to the coastal
standoff zone, indicating the effectiveness of the coastal standoff as
one of the primary mitigation measures for reducing potential impacts.
The remaining areas were broadly evaluated under the OBIA criteria and,
after review, 73 potential OBIAs were considered by the Navy and NMFS.
After the list of potential OBIAs was developed based on
information at a broad scale, each of these areas was evaluated at a
finer scale to determine whether they qualified for designation as an
OBIA. Further analysis of the biological evidence and robustness of the
data for each of these recommendations included ranking them in
categories using a numbering system ranging from 0 to 4. Any of the
nominees that received a ranking of 2 or higher were eligible for
continued consideration as an OBIA nominee. A rank score of 2 for
designation criteria or for OBIA boundary considerations indicated that
the designation was inferred from habitat suitability models (non-peer
reviewed), expert opinion, regional expertise, or ``gray literature''
(inferred from analyses conducted for purposes other than quantifying
OBIA criteria or boundary; see DoN (2012), Section 4.5.2.1). Thus, even
areas with somewhat limited data were eligible for further
consideration as an OBIA.
The systematic process described here was developed in order to
support an orderly and manageable expert review and to ensure some
definable information quality in the identification of OBIAs. As a
result of this process, 45 areas ranked a 2 or higher.
Although not part of the initial screening criteria for the 2012
rulemaking, consideration of marine mammal hearing frequency
sensitivity led NMFS to screen out areas that qualified solely on the
basis of their importance for mid- or high-frequency hearing
specialists in past rulemaking. This was due to the fact that the LFA
sound source is below the range of best hearing sensitivity for MF and
HF odontocete hearing specialists. Using the example of harbor
porpoises, this means that a sound with a frequency less than 1 kHz
would need to be significantly louder (more than 50 dB louder) than a
sound in their area of best sensitivity (around 100 kHz) in order for
them to hear it. Additionally, during the 1997 to 1998 SURTASS LFA
Sonar Low Frequency Sound Scientific Research Program (LFS SRP),
numerous odontocete and pinniped species (i.e., MF and HF hearing
specialists) were sighted in the vicinity of the sound exposure tests
and showed no immediately obvious responses or changes in sighting
rates as a function of source conditions, which likely produced
received levels similar to those that produced minor short-term
behavioral responses in the baleen whales (i.e., LF hearing
specialists). NMFS stated that MF and HF odontocete hearing specialists
have such reduced sensitivity to the LFA sonar source that limiting
ensonification in OBIAs for those animals would not afford protection
beyond that which is already incurred by implementing a shutdown when
any marine mammal enters the LFA mitigation zone. Therefore,
consideration of marine mammal frequency sensitivity led NMFS to screen
out areas that qualified solely on the basis of their importance for MF
or HF specialists.
In addition to the considerations above, NMFS reviewed Hoyt (2011),
which was an update and revision of Hoyt's 2005 earlier work, along
with areas recommended in public comments received on the 2012 DSEIS/
SOEIS. As a result of this further analysis, NMFS developed a list of
OBIAs, which were then further considered in the context of
practicability.
In response to public comments on the 2012 proposed rule, NMFS also
reevaluated its preliminary decision not to include areas that met the
criteria for sperm whales and pinnipeds, and ultimately determined such
areas would be appropriate for OBIA designation where information
established the criteria were met, and in fact noted that one OBIA
(Patagonia Shelf) had already been identified for elephant seals. While
no OBIAs had been identified for sperm whales, NMFS committed to
considering sperm whales in future analyses should supporting
information become available.
As part of the 2017 DSEIS/SOEIS, and as part of the 2017 rulemaking
process, NMFS and Navy continued their evaluation of OBIAs. As a result
of that work, NMFS and the Navy revised boundaries and designated seven
more OBIAs, for a total of 29 OBIAs that were identified and made part
of the NDE, under which the Navy is currently conducting SURTASS LFA
sonar activities. Two of these OBIAs include protection for sperm
whales (OBIA 28, Perth Canyon and OBIA 29, Southwest Australia
Canyons).
Since 2012, the Navy and NMFS have maintained a ``watch list'' of
potential marine areas for which information or data have not been
sufficient to designate as OBIAs, and reviewed new literature to
determine if additional areas should be added to the list of potential
areas. The watch list is periodically evaluated or re-assessed as
additional information and data are available to determine if new
information provides adequate support under one of the OBIA biological
criteria. NMFS refers the reader to the SURTASS 2018 DSEIS/SOEIS,
Chapter 5 and Appendix C for more detail on the analysis of potential
OBIAs. As part of the ongoing Adaptive Management component of the 2012
final rule, and in preparation for the 2018 DSEIS/SOEIS, NMFS and Navy
reviewed the watch list and other new information to determine the
potential for additional OBIAs or expansion of existing OBIAs within
the SURTASS LFA sonar study area.
Offshore Biologically Important Areas--Proposal for Current Rulemaking
For the SURTASS 2018 DSEIS and this proposed rule, the following
biological, geographic, and LF hearing sensitivity factors are
considered in the identification of OBIAs:
Biological Criteria--As with other biological criteria, critical
habitat is considered as one of the possible factors in the OBIA
process, but designation as critical habitat does not necessarily
comport with designation as an OBIA due to differences in the intent of
these designations. Critical habitat is defined and used in the ESA and
includes specific geographic areas that contain features essential to
the conservation of an endangered or threatened species, including
areas that are not currently occupied by the relevant species. However,
as stated above, the intent of OBIA designation is to expand upon the
coastal standoff, and provide protection from potential SURTASS LFA
sonar
[[Page 7234]]
impacts by avoiding or minimizing impacts in areas beyond the coastal
standoff distance where marine mammals are known to engage in specific
behaviors that may lead to more severe impacts if interrupted; known to
congregate in higher densities; and/or known to have a limited range
and small abundance that creates more vulnerability for the stock as a
whole. Therefore, at least one of the following biological criteria
must be met for a marine area to be considered as a marine mammal OBIA
for SURTASS LFA sonar. When direct data relevant to one of the
following are limited, other available data and information may be used
if those data and information, either alone or in combination with
limited direct data, are sufficient to establish that at least one of
the biological criteria are present:
Known Breeding/Calving or Foraging Ground, or Mitigation
Route--an area representing a location of known biologically important
activities including defined breeding or calving areas, foraging
grounds, or migration routes. Potential designation under this
criterion is indicative that these areas are concentrated areas for at
least one biologically important activity. ``Concentrated'' means that
more of the animals are engaged in the particular behavior at the
location (and perhaps time) than are typically engaged in that behavior
elsewhere.
Small, Distinct Populations of Marine Mammals with Limited
Distributions--geographic areas in which small, distinct populations of
marine mammals occur and whose distributional range are limited.
High Densities--an area of high density for one or more
species of marine mammal. High density areas are those marine waters
where the density within a definable area (and potentially time),
measurably and meaningfully exceeds the average density of the species
or stock within the region. The exact basis for the identification of
high density areas may differ across species/stocks and regions/scales,
depending on the available information and should be evaluated on a
stock-by-stock basis, although combining species or stocks may be
appropriate in some situations. The best source for this type of
determination is publically-available, direct measurements from survey
data.
Geographic Criteria--For a marine area to be eligible for
consideration as an OBIA for marine mammals, the area must be located
where training and testing activities of SURTASS LFA sonar would occur
and cannot be located within 12 nm (22 km) of any emergent land
including islands or island systems (must be outside of the coastal
standoff zone, which already receives the same protection as OBIAs).
LF Hearing Sensitivity--SURTASS LFA sonar transmissions are well
below the range of best hearing sensitivity for most odontocetes and
most pinnipeds based on the measured hearing thresholds (Au and
Hastings, 2008; Houser et al., 2008; Kastelein et al., 2009; Mulsow and
Reichmuth, 2010; Nedwell et al., 2004; Richardson et al., 1995;
Southall et al., 2007). The intent of OBIAs is to protect those marine
mammal species, such as baleen whales, most likely to hear and be
affected by LFA sonar transmissions and to provide them additional
protections during periods when they are conducting biologically
significant activities. Thus, the primary focus of the OBIA mitigation
measure is on LF hearing specialist species. However, OBIAs have been
designated to provide additional mitigation protection for non-LF
hearing specialists, such as elephant seals and sperm whales, since the
available hearing data for these species indicate an increased
sensitivity to LF sound (compared to most odontocetes and pinnipeds).
The biological criteria considered in the identification of OBIAs
have changed since the 2001 FOEIS/EIS (and as continued in the 2007
SEIS) in two respects. First, under the 2001 FOEIS/EIS, 2007 SEIS, and
the 2007 Final Rule, an area could be designated as an OBIA only if it
met a conjunctive test of being an area where: Marine mammals
congregate (1) in high densities, and (2) for a biologically important
purpose. The current scheme is more protective because any one of the
biological criteria alone could be a sufficient basis for designation
as an OBIA if it also meets the geographic criterion of falling outside
of 12 nmi (22 km) from any coastline. Second, the current biological
criteria include ``small, distinct populations with limited
distribution'' that also could, standing alone, be a basis for
designation.
The 2017 NDE for SURTASS LFA sonar lists the 29 marine mammal OBIAs
and their effective periods as geographic mitigation with which the
Navy must comply for SURTASS LFA sonar activities. These OBIAs resulted
from analyses conducted as part of the 2017 SEIS/SOEIS and application
for rulemaking, and retained existing OBIAs; revised/expanded existing
OBIAs; and added new OBIAs to those defined as part of the 2012 SURTASS
LFA sonar rule (also see the SURTASS 2018 DSEIS/SOEIS, 5.3.6.2 and
Appendix C for more detail on OBIAs). Of these 29 OBIAs, four are
located within the current SURTASS LFA sonar study area (OBIA 16,
Penguin Bank, Hawaiian Islands Humpback Whale NMS; OBIA 20, Northern
Bay of Bengal and Head of Swatch-of-No-Ground; OBIA 26, Offshore Sri
Lanka; and OBIA 27, Camden Sound/Kimberly Region), as indicated in
Table 19, below.
Since the 2017 SEIS/SOEIS and NDE for SURTASS LFA sonar, analysis
and assessment of marine areas as potential OBIAs has continued. For
this proposed rule, we have applied the OBIA biological, geographic,
and hearing sensitivity factors, as well as the practicability
criterion, and are considering only areas within the study area
(central and western North Pacific and eastern Indian Oceans). This
analysis includes review of the OBIA watchlist as well as a review of
Important Marine Mammal Areas (IMMAs), Ecologically or Biologically
Significant Marine Areas (EBSAs), and the International Union for
Conservation of Nature (IUCN) Green List of Protected and Conserved
Areas that are located within the study area. More information about
IMMAs, EBSAs, and IUCN Green List of Protected and Conservation Areas
is provided below followed by a discussion of the review of these areas
for consideration as OBIAs, which is ongoing and will be completed for
the final rule. In Table 19 we list the OBIAs that were previously
identified and are currently proposed for inclusion in this rule (i.e.,
that fall within the identified area covered by the rule (central and
western North Pacific and eastern Indian Oceans)).
Table 19--Marine Mammal OBIAs Currently Observed for SURTASS LFA Sonar
----------------------------------------------------------------------------------------------------------------
Relevant low-
OBIA No. Name of OBIA Location/water body frequency marine Effectiveness
mammal species seasonal period
----------------------------------------------------------------------------------------------------------------
16....................... Penguin Bank, North-Central Humpback whale...... November through
Hawaiian Islands Pacific Ocean. April, annually.
Humpback Whale NMS.
[[Page 7235]]
20....................... Northern Bay of Bay of Bengal/ Bryde's whale....... Year-round.
Bengal and Head of Northern Indian
Swatch-of-No- Ocean.
Ground (SoNG).
26....................... Offshore Sri Lanka.. North-Central Indian Blue whale.......... December through
Ocean. April, annually.
27....................... Camden Sound/ Southeast Indian Humpback whale...... June through
Kimberly Region. Ocean; northwestern September,
Australia. annually.
----------------------------------------------------------------------------------------------------------------
IMMAs are defined by the Marine Mammal Protected Areas Task Force
(MMPATF), which is comprised of partners from the International Union
for Conservation of Nature (IUCN) World Commission on Protected Areas
(WCPA); IUCN Species Survival Commission (SSC); International Committee
on Marine Mammal Protected Areas (ICMMPA); Tethys Research Institute;
Whale and Dolphin Conservation (WDC); Global Ocean Biodiversity
Initiative (GOBI), and Water Evolution organizations. These areas are
defined as discrete portions of habitat that are important to one or
more marine mammal species; represent priority sites for marine mammal
conservation worldwide without management implications; and merit
protection and monitoring. IMMA selection criteria are designed to
capture aspects of the biology, ecology, and population structure of
marine mammals and a candidate IMMA need only satisfy one of the
following criteria and/or sub-criteria to successfully qualify for IMMA
status: Criterion A--Species or Population Vulnerability; Criterion B--
Distribution and Abundance; Criterion C--Key Life Activities; or
Criterion D--Special Attributes. To date, IMMAs have been identified
and made publicly available only for the western and central Pacific
Ocean and Mediterranean Sea (MMPATF, 2018), six of which are in the
North Pacific.
EBSAs are an effort of the Convention on Biological Diversity
(Convention), which was initiated by the United Nations Environment
Programme (UNEP). The Convention is an international legal instrument
for the conservation and sustainable use of biological diversity. EBSAs
are defined as special marine areas that serve important purposes that
ultimately support the healthy functioning of oceans and thus should
have increased protection and sustainable management. Currently there
are 278 EBSAs defined worldwide, 129 of which are within the central or
western North Pacific or eastern Indian Oceans.
The IUCN Green List of Protected and Conserved Areas has been
generated as part of an IUCN program that aims to encourage, achieve,
and promote effective, equitable, and successful protected areas with a
principal goal of increasing the number of protected and conserved
areas that are effectively and equitably managed and deliver
conservation outcomes. The basis of the IUCN Green List Programme is
the Green List Standard, which is a set of components, criteria, and
indicators for successful protected area conservation and international
benchmarks for quality to provide improved performance and achievement
of conservation objectives (IUCN, 2018). The Programme has recognized
25 protected and conserved areas in eight countries around the world,
11 of which are within the SURTASS LFA sonar study area.
NMFS assessed these areas (IMMAs, EBSAs, and IUCN areas) to
determine whether they contained characteristics that matched the
criteria necessary for identifying an OBIA. The initial assessment for
each marine area was a geospatial analysis to determine if the marine
area was located within the study area and outside of the coastal
standoff range for SURTASS LFA sonar (i.e., >12 nmi (22 km) from any
emergent land). Another key step in the assessment of marine areas for
designation as OBIAs is determining the area's relevance specific to
marine mammals under NMFS' jurisdiction, as many of the EBSAs and other
marine areas are defined for their importance to other marine taxa
(fish, invertebrates, etc.), or for their importance for general marine
conservation. For example, of the six IMMAs designated in the North
Pacific Ocean, three were located in the SURTASS LFA sonar study area
but only two were located offshore of the coastal standoff range and
were carried forward for consideration as OBIAs; review of the 278
identified EBSAs revealed only 12 EBSAs that were within the SURTASS
LFA sonar study area outside of the coastal standoff range, and were of
noted importance to marine mammal species for which NMFS has
jurisdiction (and one additional EBSA was added for consideration due
to other factors, as discussed below); and review of the 25 recognized
IUCN Green List of Protected and Conserved Areas identified 11 areas
within the SURTASS LFA sonar study area, though none of these
encompassed any marine waters, so none of these areas were considered
further. A summary of the areas assessed is presented in Table 20,
below.
Table 20--Number and Types of Marine Areas Assessed as Potential OBIAs
----------------------------------------------------------------------------------------------------------------
Number of
Number of Number of areas located Number of
areas relevant areas located outside of areas for
Name/region to marine within SURTASS coastal further
mammals LFA sonar standoff consideration
study area range
----------------------------------------------------------------------------------------------------------------
OBIA Watchlist Areas
----------------------------------------------------------------------------------------------------------------
--Pacific Remote Islands MNM
--Marianas Trench MNM
--Papahanaumokuakea MNM
----------------------------------------------------------------------------------------------------------------
[[Page 7236]]
TOTAL OBIA Watchlist Areas For Further Consideration = 3 *
----------------------------------------------------------------------------------------------------------------
EBSAs
----------------------------------------------------------------------------------------------------------------
Northeast Indian Ocean.......................... 5 10 9 2
South and Western Indian Ocean.................. 14 5 4 0
East Asian Seas................................. 11 32 13 7
North Pacific Ocean............................. 15 6 6 4
Western South Pacific Ocean..................... 9 2 2 0
---------------------------------------------------------------
TOTALS...................................... 54 55 34 13
----------------------------------------------------------------------------------------------------------------
IMMAs
----------------------------------------------------------------------------------------------------------------
Western and Central North Pacific Ocean......... 6 3 2 2
----------------------------------------------------------------------------------------------------------------
IUCN Green List of Protected and Conserved Areas
----------------------------------------------------------------------------------------------------------------
Asian Pacific................................... 0 0 0 0
----------------------------------------------------------------------------------------------------------------
* Four watchlist areas were advanced for further consideration as OBIAs, but for three of these areas (the
MNMs), only a portion of the area met the all of the geographic criteria for consideration.
Review of OBIA Watchlist Marine Areas as OBIAs--As noted above,
NMFS and the Navy have maintained a watchlist of potential marine areas
that have already been identified and reviewed as potential OBIAs, but
for which documentation on the importance of the area to marine mammals
has not been established or is lacking in sufficient detail. As the
watchlist was developed under previous rules that considered worldwide
SURTASS LFA sonar operations, the areas are dispersed globally. The
majority of these watchlist areas are not located in the current
SURTASS LFA sonar study area (central or western North Pacific and
eastern Indian Oceans). Only the watchlist areas within the current
SURTASS LFA sonar study area have been re-evaluated for consideration
as OBIAs including: The Pacific Remote Islands (PRI) Marine National
Monument (MNM); Marianas Trench MNM; and the Papahanaumokuakea MNM. The
British Indian Ocean Territory (BIOT)-Chagos Islands MPA is large,
encompassing an area of 158,605 nmi\2\ (544,000 km\2\) in the central
Indian Ocean, the majority of which lies outside the coastal standoff
range for SURTASS LFA sonar. However, little information is available
on marine mammals that use these remote waters or of what important
biological activities of marine mammals may be conducted in these
waters. Available literature and information was researched and
reviewed, but the Navy and NMFS' conclusion on this area remains the
same, that insufficient data are available to demonstrate that the
waters of this MPA are important biologically to marine mammals.
Accordingly, the Navy and NMFS are retaining the BIOT-Chagos Islands
MPA on the OBIA Watchlist and not moving forward for consideration as
an OBIA at this time. Not all areas of these MNMs met the geographic
criteria. The Marianas Trench MNM consists of three units, but only one
unit (The Islands unit) met the geographic criteria. The Islands unit
consists of the waters and submerged lands of the three northernmost
Mariana Islands, while the other two units consist solely of submerged
lands and include no waters. Additionally, only two of the PRI MNM
units (Wake and Johnson atolls) were located wholly within the study
area, and only a very small strip of part of a third PRI MNM unit
(Kingman Reef/Palmyra Atoll) was within the study area. Therefore, only
those areas of the MNMs within the study area were further considered.
Review of EBSAs as OBIAs--EBSAs from five geographic regions, as
classified by the Convention (https://www.cbd.int/ebsa/ebsas), in the
Indian and North Pacific Oceans in which all or part of the SURTASS LFA
sonar study area is located were assessed as potential OBIAs. The five
pertinent EBSA regions include: North-East Indian Ocean, Southern
Indian Ocean, East Asian Seas, North Pacific Ocean, and Western South
Pacific Ocean. All EBSAs in these regions were assessed to determine
their relevance to marine mammal species under NMFS' jurisdiction.
Forty-four of the EBSAs were noted of importance to marine mammals.
However, only 13 of these met the preliminary relevance and geographic
criteria for OBIAs and were carried forward for further review for
consideration as OBIAs. Although the Ogasawara Island EBSA (included in
the 13 carried forward for further review) was located entirely within
the coastal standoff range, waters beyond the coastal standoff for this
area are being further considered to see if an area can be defined in
which important reproductive behaviors occurs and sufficient data
supports its designation as an OBIA due to the fact that the Ogasawara
area is an important reproductive area for the western North Pacific
DPS and stock of humpback whale.
Review of IMMAs as OBIAs--Three identified IMMAs are located within
the SURTASS LFA sonar study area, including: Northwest Hawaiian
Islands; Main Hawaiian Islands; and the Southern Shelf Waters and Slope
Edge of Palau IMMAs. However, the geographic extent of the Palau IMMA
is located entirely within the coastal standoff range; therefore, two
of these three IMMAs were carried forward for consideration as OBIAs.
Review of IUCN Green List of Protected and Conserved Areas as
OBIAs--While these areas have been designated in four global geographic
regions, only the Asia Pacific region is
[[Page 7237]]
located within or near the SURTASS LFA sonar study area. Although 11
areas are located in the Asian Pacific region, only one (Montague
Island Nature Reserve) is located in the marine environment. However,
this area is located entirely on the Island with no adjacent waters
conserved. Therefore, none of these areas have importance to marine
mammals such that consideration as OBIAs is warranted.
In addition to evaluation of OBIA watch list areas, EBSAs, IMMAs,
IUCN Green List of Protected and Conserved Areas (discussed above), and
Critical Habitat areas (discussed below), NMFS and the Navy evaluated
areas that were suggested as OBIAs in a public comment received on the
SURTASS DSEIS/SOEIS. The NRDC's comment on the SURTASS DSEIS/SOEIS
recommended 19 areas for consideration as OBIAs. However, six of these
areas were already included in the areas under consideration in the
SURTASS DSEIS/SOEIS. Additionally, eight of the areas suggested by NRDC
did not meet the geographic criteria (i.e., were either located within
the coastal standoff or not within the study area), or did not align
with OBIA eligibility criteria (area important for marine mammals not
under NMFS' jurisdiction (dugong), or suggested area for a DPS not
anticipated to occur in the study area (Arabian Sea DPS of humpback
whale)). The remaining five areas suggested by NRDC received further
consideration for potential as OBIAs. Therefore, 25 areas comprised of
13 EBSAs; 2 IMMAs; 3 OBIA watch list areas; 2 critical habitat areas;
and 5 NRDC DSEIS/SOEIS recommendation areas were further considered for
potential OBIA designation.
A list of the 25 areas considered for potential designation as new
OBIAs for this rulemaking, as described above, is presented in Table 21
below. Further, NMFS and the Navy have identified the subset of these
areas that, based on additional preliminary analysis, satisfy at least
one of the biological criteria and met the geographic criteria. The 25
areas that were further considered, and the existing information that
supports our additional preliminary analysis, are summarized in a
document entitled Potential Marine Mammal OBIAs for SURTASS LFA Sonar;
Marine Areas Under Consideration, which is incorporated by reference
into this proposed rule, and has been posted on NMFS' website at
https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-
navy-operations-surveillance-towed-array-sensor-system-0, as well as
the Navy's SURTASS LFA Sonar website at http://www.surtass-lfa-eis.com.
Table 21--Marine Areas for Further Consideration as Marine Mammal Offshore Biologically Important Areas (OBIAs) for SURTASS LFA Sonar
--------------------------------------------------------------------------------------------------------------------------------------------------------
Preliminarily meeting
Name of marine Marine mammal Geographic Biological Type of marine geographic, LF-
Area # area Ocean basin species of criteria criteria area sensitivity, and
concern biological criteria
--------------------------------------------------------------------------------------------------------------------------------------------------------
1............. Papah[amacr]naumo Central North Humpback whale; Majority of area Breeding/calving. Marine National Yes.
ku[amacr]kea Pacific Ocean. Hawaiian monk outside coastal Monument; ESA
Marine National seal. standoff range Designated
Monument. (CSR). Critical Habitat
for the Hawaiian
monk seal also
is located in
these waters
(OBIA Watchlist).
2............. Marianas Trench Western North Humpback, 38 nmi outside Breeding/calving, Marine National Yes.
Marine National Pacific Ocean. Bryde's, sei, CSR surrounding migration. Monument (OBIA
Monument. common minke, each of three Watchlist).
and sperm whales. islands.
3............. Trincomalee Northeast Indian Sperm and blue Part of area Foraging, EBSA............. Yes.
Canyon and Ocean. (pygmy) whales. outside CSR. migration.
Associated
Ecosystems.
4............. Southern Coastal/ Northeast Indian Blue (pygmy) Part of area Foraging, EBSA............. Yes.
Offshore Waters Ocean. whale. outside CSR; breeding/
between Galle OBIA #26 calving,
and Yala overlaps with migration.
National Park. part of area
outside CSR.
5............. Modification of Western North Humpback whale... Part of area Breeding/calving. EBSA............. Yes.
Bluefin Spawning Pacific Ocean. outside CSR.
EBSA.
6............. Convection Zone Western North Gray whale....... Outside CSR...... Foraging, EBSA............. Yes.
East of Honshu. Pacific Ocean. migration.
7............. Ogasawara Islands Western North Humpback whale... EBSA inside CSR; Breeding/calving. EBSA............. Yes.
Pacific Ocean. examine area
surrounding
islands > CSR
\1\.
8............. Upper Gulf of Western North Bryde's whale, Part of area Foraging, EBSA............. Yes.
Thailand. Pacific Ocean. dolphins and outside CSR. Breeding/calving.
porpoise.
9............. Southeast Western North Gray, killer, Small part Foraging, EBSA............. Yes.
Kamchatka Pacific Ocean. humpback, fin, outside CSR. migration.
Coastal Waters. and North
Pacific right
whales; Steller
sea lion.
10............ Northwestern Central North Humpback whale, Partially outside Breeding/calving, IMMA............. Yes.
Hawaiian Islands. Pacific Ocean. Hawaiian monk of CSR. Small distinct
seal; spinner population,
dolphin. critical habitat.
11............ West of Maldives. Central Indian Blue (pygmy), Outside of CSR... Migration, NRDC DSEIS/SOEIS Yes.
Ocean. Bryde's whale. foraging. Recommendation.
[[Page 7238]]
12............ North Western Southeast Indian Blue (pygmy) Outside of CSR... Migration........ NRDC DSEIS/SOEIS Yes.
Australian Shelf. Ocean. whale. Recommendation.
13............ Browse Basin Southeast Indian Blue (pygmy) Outside of CSR... Migration........ NRDC DSEIS/SOEIS Yes.
(North Western Ocean. whale. Recommendation.
Australia).
14............ Western Australia Southeast Indian Humpback whale... Partially outside Migration........ NRDC DSEIS/SOEIS Yes.
(Shark Bay to Ocean. of CSR. Recommendation.
Exmouth Gulf).
15............ Pacific Remote Western North Baleen, beaked, Small part of Small distinct Marine National No.
Island Marine Pacific. and sperm northern end of population. Monument (OBIA
National whales; dolphins. Kingman Reef/ Watchlist).
Monument (Wake/ Palmyra Atoll
Johnson/Palmyra within LFA Study
atolls and Area.
Kingman Reef
units only).
16............ Hawaiian Monk Central North Hawaiian monk Within CSR except Breeding/calving, ESA Critical No.
Seal Critical Pacific. seal. for Penguin foraging. Habitat for
Habitat. Bank, which is Hawaiian monk
enclosed within seal.
OBIA #16
(Penguin Bank).
17............ Main Hawaiian Central North False killer Part of area High-density ESA Critical No.
Island Insular Pacific. whale. outside CSR. where foraging Habitat for Main
DPS of False and/or breeding/ Hawaiian Islands
Killer Whale calving may Insular DPS of
Critical Habitat. occur. false killer
whale.
18............ Kyushu Palau Western North Sperm whale...... Outside CSR...... Possible foraging EBSA............. No.
Ridge. Pacific.
19............ Raja Ampat and Western North Bryde's, false Small portion of Migration, EBSA............. No.
Northern Bird's Pacific Ocean. killer, killer, Bird's Head foraging
Head. and sperm Seascape occurs (Straits outside
whales; dolphins. within LFA Study LFA study area
Area. may function in
migration).
20............ North Pacific North Pacific Northern elephant Outside CSR...... Foraging......... EBSA............. No.
Transition Zone. Ocean. seal.
21............ Peter the Great Sea of Japan..... Spotted seal..... Part of area Breeding/calving, EBSA............. No.
Bay. outside CSR. foraging.
22............ Moneron Island Sea of Japan..... Steller sea lion. Part of area Breeding/calving. EBSA............. No.
Shelf. outside CSR.
23............ Kuroshio Current Western North Finless porpoise. Part of area Breeding/calving. EBSA............. No
South of Honshu. Pacific Ocean. outside CSR.
24............ Main Hawaiian Central North Hawaiian monk Part of area Breeding/calving IMMA............. No.
Archipelago. Pacific Ocean. seal, humpback, outside CSR. (humpback whale
false killer, and Hawaiian
Blainville's monk seal
beaked, Cuvier's enclosed within
beaked, and OBIA #16,
melon-headed Penguin Bank);
whales. small, resident
populations.
25............ Polar/Kuroshio North Pacific Sei whale........ Outside CSR...... High density, NRDC DSEIS/SOEIS No.
Extension Fronts. Ocean. foraging. Recommendation.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Even though this EBSA boundary is inside the coastal standoff range, since this is such an important reproduction area for the endangered WNP
humpback whale, the Navy and NMFS are further evaluating the waters beyond 12 nmi.
NMFS will consider additional information received during the
public comment period when further evaluating if these areas satisfy
the criteria for OBIA designation. Following the public comment period
and consideration of additional information provided, for areas that we
conclude satisfy the OBIA criteria, NMFS and the Navy will evaluate the
practicability of the measure, which for military readiness activities
``shall include consideration on personnel safety, practicality of
implementation, and impact on the effectiveness of the military
readiness activity.'' In accordance with the LPAI Standard, NMFS' final
rule will include the rationale for which areas satisfied the OBIA
criteria, a discussion of practicability, and the list of those
designated as OBIAs.
Other Geographic Mitigation Considerations
Above, we describe a comprehensive process and set of criteria for
identifying OBIAs, which if used in conjunction with the limits on
SURTASS LFA sonar transmission levels in and around them described
above, we expect to decrease the likelihood and/or scale of impacts on
marine mammal species or stocks. However, the inclusion of this focused
and systematic process and criteria for designating OBIAs does not mean
that other mitigation, including specific time/area restrictions, could
not be considered in the context of the LPAI standard. Below we address
some other factors that NMFS and the Navy have
[[Page 7239]]
considered in the development of the proposed rule.
Critical Habitat
Under section 7 of the ESA, all Federal agencies must ensure that
any actions they authorize, fund, or carry out are not likely to
jeopardize the continued existence of a listed species or destroy or
adversely modify its designated critical habitat. Critical habitat is
not designated in foreign countries or any other areas outside of U.S.
jurisdiction. Critical habitat within the U.S. EEZ implicated by
SURTASS LFA sonar activities has been designated for two of the
relevant ESA-listed marine mammal species, Hawaiian monk seals and the
Main Hawaiian Island (MHI) Insular DPS of false killer whales. Effects
to critical habitat are being explicitly addressed through the section
7 consultation process under the ESA. Some of the characteristics of
ESA critical habitat are germane to the identification of OBIAs under
this rulemaking. However, critical habitat also considers physical as
well as biological features and may also consider areas that are
currently unoccupied by the species. Therefore, not all critical
habitat qualifies as an OBIA, or is otherwise appropriate for time/area
restrictions when making determinations under the MMPA. Further, we
note that neither of these two ESA-listed species is a low frequency
hearing specialist or sensitive to SURTASS LFA in a manner that would
otherwise justify designation of a mitigation area on their behalf,
given the existing protections of the Navy's three-part detection and
shutdown protocols.
Nearly all of the critical habitat for the Hawaiian monk seal lies
within the coastal standoff distance for SURTASS LFA sonar. A small
area of the monk seal's critical habitat at Penguin Bank extends beyond
the 22-km (12-nmi) coastal standoff distance, and is part of the
existing Penguin Bank, Hawaiian Islands Humpback Whale NMS (OBIA 16).
In addition, per the CZMA consultation with the State of Hawaii for
SURTASS LFA sonar, the Navy agreed not to operate SURTASS LFA sonar in
state waters (out to 3 nmi) or in waters of Penguin Bank to the 600-ft
(183-m) isobath, which is the boundary of the Penguin Bank OBIA for
SURTASS LFA sonar. In addition, the Navy also agreed not to ensonify
Hawaii state waters at levels above 145 dB. Thus, the critical habitat
of the Hawaiian monk seal beyond the coastal standoff range would not
be exposed to SURTASS LFA sonar training and testing activities and the
small portion of critical habitat that may qualify for consideration as
an OBIA is already covered by an existing OBIA. Thus, the entire
critical habitat is covered by some form of geographic mitigation.
The critical habitat for the MHI insular false killer whale (MHI
IFKW) DPS includes waters from the 148- to 10,499-ft (45-to 3,200-m)
depth contours around the MHI from Niihau east to Hawaii. MHI IFKWs are
island-associated whales that rely entirely on the productive submerged
habitat of the main Hawaiian Islands to support all of their life-
history stages, and their range is restricted to the shelf and slope
habitat around the MHI, unlike pelagic false killer whales found more
in open oceans. Because of the habitat characteristics that are
important components to the ecology of these whales, NMFS identified a
single feature, (island-associated marine habitat for MHI IFKWs) with
four characteristics that support this feature as essential to their
conservation. The four characteristics include: (1) Adequate space for
movement and use within shelf and slope habitat; (2) prey species of
sufficient quantity, quality, and availability to support individual
growth, reproduction, and development, as well as overall population
growth; (3) waters free of pollutants of a type and amount harmful to
MHI IFKWs; and (4) sound levels that will not significantly impair
false killer whales' use or occupancy.
Some Navy and other Federal agency areas, such as the Pacific
Missile Range Facility offshore ranges, are excluded from the critical
habitat designation (NOAA, 2018). In most areas of the waters
surrounding the MHI, the coastal standoff range for SURTASS LFA (12 nmi
(22 km)) is located closer to shore than the seaward boundary of the
critical habitat for the MHI Insular DPS of the false killer whale
(i.e., some of the critical habitat is beyond the coastal standoff
range). The Penguin Bank OBIA encompasses some of the critical habitat,
but a portion of the critical habitat lies beyond, or in deeper waters,
than the OBIA. However, as discussed above, part of the CZMA
stipulations for SURTASS LFA sonar use in Hawaiian waters required the
Navy to agree not to use SURTASS LFA sonar in the waters (out to 3 nmi)
or over Penguin Bank to a water depth of 600 ft (183 m) and to limit
ensonification within Hawaii state waters to 145 dB.
Regarding prey availability (large pelagic fish and squid) of
sufficient quantity, quality, and availability to support individual
growth, reproduction, and development, as well as overall population
growth of false killer whales, no mortality of marine invertebrates is
reasonably expected to occur from exposure to LFA sonar training and
testing activities nor are population level effects likely. Thus,
marine invertebrates such as squid would not reasonably be adversely
affected by SURTASS LFA sonar training and testing activities such that
their availability (or other prey availability) would be diminished
(also refer to Chapter 3, section 3.4.2.1 of the SURTASS DSEIS/SOEIS
for a discussion of why marine invertebrates are not reasonably likely
to be adversely impacted by SURTASS LFA sonar training and testing
activities). Marine fishes, however, may be affected by exposure to LFA
sonar transmissions, but only if they are located within close
proximity (<0.54 nmi (<1 km)) to the transmitting sonar source. The
Navy's analysis indicates a minimal to negligible potential for an
individual fish to experience non-auditory or auditory effects or a
stress response from exposure to SURTASS LFA sonar transmissions. A low
potential exists for minor, temporary behavioral responses or masking
effects to an individual fish when LFA sonar is transmitting, but no
potential is estimated for fitness level consequences to fish stocks.
Since it is highly unlikely that a significant percentage of any prey
stock would be in sufficient proximity during LFA sonar transmissions
to experience such effects, there is minimal potential for LFA sonar to
affect prey fish stocks. Thus, no adverse effects are reasonably
expected on the quantity, quality, and availability of prey fishes as
the result of exposure to SURTASS LFA sonar training and testing
activities. Accordingly, SURTASS LFA sonar training and testing
activities would not significantly impact the biological characteristic
of prey availability of the MHI Insular DPS of the false killer whale's
designated critical habitat.
Regarding the underwater sound produced by SURTASS LFA sonar, it
would not be expected to ``significantly impair false killer whale's
use or occupancy'' due both to the small scale of the activity (small
number of vessels operating across two ocean basins, meaning that any
individual marine mammal would be expected to be exposed for only a
short amount of time) and the frequency of the SURTASS signal, which is
not in the range of higher sensitivity for this species and would not
be expected to interfere with their communication. Further, required
shutdowns are expected to minimize false killer whale exposure to high
sound levels and the Navy's implementation of a coastal standoff
[[Page 7240]]
zone means that SURTASS LFA training and testing is not occurring
across much of the critical habitat. No aspect of SURTASS LFA sonar
training and testing activities would reasonably be expected to impact
the spatial use of false killer whales. As a result, the use of SURTASS
LFA sonar for training and testing activities in Hawaiian waters would
not reasonably be expected to have any impact on the physical
characteristics of the false killer whale critical habitat since
neither the spatial availability nor sound levels in the continental
shelf and slope habitat would be significantly impacted. Accordingly,
NMFS is not recommending additional geographic mitigation in this area.
Both the Navy and NMFS Protected Resources Permits and Conservation
Division are consulting with NMFS Protected Resources Interagency
Cooperation Division on effects on critical habitat pursuant to section
7 of the ESA. Consultations under previous rules and LOAs have resulted
in determinations that neither NMFS' nor the Navy's actions are likely
to jeopardize the continued existence of any ESA-listed species or
destroy or adversely modify designated critical habitat.
Expanded Coastal Standoff Zone
As proposed, the Navy will restrict training and testing activities
utilizing SURTASS LFA sonar within 22 km (14 mi; 12 nmi) of any
coastline, including islands, such that the SURTASS LFA sonar-generated
sound field will not exceed 180 dB re: 1 [mu]Pa (RL) at that seaward
distance. This measure is intended to minimize both the severity and
scale of effects to marine mammals and, by extension, marine mammal
species and stocks, by avoiding areas where many biologically important
behaviors and higher densities of many species that may be found in
coastal areas occur. In the past, some commenters have recommended the
Navy implement a larger coastal standoff zone than is currently
proposed in this rule. We reiterate that our analysis shows that
approximately 80 percent of known and potential marine protected areas
are within the 22 km (12 nmi) coastal standoff zone, an indication of
this measure's effectiveness, and it is practicable. Additionally, this
restriction limits exposures of marine mammals to high-level sounds in
the vicinity of geographical features that have been associated with
some stranding events (i.e., enclosed bays, narrow channels, etc.)
attributed to activities other than SURTASS LFA sonar.
The Navy's 2007 SEIS/SOEIS evaluated increasing the coastal
standoff distance up to 46 km (25 nmi) and, based on a six-step
analysis process, determined that increasing the coastal standoff range
would decrease exposure to higher received levels for concentrations of
marine animals closest to shore, but would do so at the expense of
increasing exposure levels for shelf break and pelagic species. There
have been no changes to the best available information or other
indications that the coastal standoff distance should be increased, so
there is no change in this mitigation measure from previous
rulemakings. In addition, any areas beyond the 12 nmi coastal standoff
that are biologically significant are considered as part of the OBIA
process.
Commercial and Recreational SCUBA Diving Mitigation Zone
The Navy will establish a mitigation zone for human divers at 145
dB re: 1 [micro]Pa at 1 m around all known human commercial and
recreational diving sites. Although this geographic restriction is
intended to protect human divers, it will also reduce the LFA sound
levels received by marine mammals located in the vicinity of known dive
sites.
White Paper on ``Identifying Areas of Biological Importance to
Cetaceans in Data-Poor Regions''
As described earlier, for the 2012 rulemaking, NMFS convened a
panel of subject matter experts (SMEs) to help identify marine mammal
OBIAs relevant to the Navy's use of SURTASS LFA sonar. Separately, we
consulted a NMFS scientist, who was also on that same SME panel, to
help address a recommendation in a public comment that NMFS consider a
global habitat model (Kaschner et al., 2006) in the development of
OBIAs. In addition to providing the requested input (which essentially
concluded that using the Kaschner model was not advisable, for several
reasons), the NMFS scientist, in conjunction with other NMFS
scientists, went further and provided some guidance for alternate
methods for considering ``data poor areas'' and drafted a paper
entitled ``Identifying Areas of Biological Importance to Cetaceans in
Data-Poor Regions'' (referred to in this notice as the ``White
Paper''). NMFS' consideration of the White Paper was discussed in the
9th Circuit's ruling on our 2012 Final Rule, and as a consequence we
provide here some additional details and background regarding our
consideration of the White Paper recommendations for this proposed
rulemaking.
Kaschner et al. (2006) Recommendation
As requested, the White Paper authors reviewed the Kaschner et al.
(2006) paper in the context of potential mitigation for SURTASS LFA
sonar. The Kaschner et al. (2006) paper used models based on a
synthesis of ``existing and often general qualitative observations
about the spatial and temporal relationships between basic
environmental conditions and a given species' presence'' to ``develop a
generic quantitative approach to predict the average annual geographic
ranges'' of marine mammal species on a global scale. Several
environmental correlates including depth, sea surface temperature,
distance to land, and mean annual distance to ice edge were used in the
Kaschner effort. After evaluating four case studies from the Kaschner
et al. (2006) study for predicting gray whale, northern right whale
dolphin, North Atlantic right whale, and narwhal distribution, the
authors of the White Paper concluded that ``(t)he predictions from the
four case studies . . . included errors of omission (exclusion of areas
of known habitat) and commission (inclusion of areas that are not known
to be habitat) that could have important implications if the model
predictions alone were used for decision making in a conservation or
management context.''
Specifically, the White Paper illustrated that the Kaschner et al.
effort omitted a considerable portion of known gray whale habitat;
overestimated the range of suitable habitat for northern right whale
dolphins off the U.S. West Coast (noting that species-specific models
based on dedicated shipboard surveys more correctly identified suitable
habitat); predicted habitat for North Atlantic right whales in large
areas where they have never been recorded; and predicted suitable
habitat for narwhal that did not correspond with their known
distribution. Noting that these significant inaccuracies in the model
could result in either under-protection or over-restrictiveness, the
authors of the White Paper did not recommend basing the identification
of biologically important areas on this modeling. NMFS concurred with
this recommendation and elected not to use the Kaschner paper, or other
similar predictive envelope models as a basis for identifying
additional protective areas in the 2012 SURTASS LFA sonar incidental
take rule.
[[Page 7241]]
Clarification of Concepts Raised in White Paper
In NRDC v. Pritzker, referring to the White Paper and its specific
recommendations that NMFS did not adopt for identification of OBIAs,
the 9th Circuit stated that NMFS, in its 2012 rule, ``did not give
adequate protection to areas of the world's oceans flagged by its own
experts as biologically important, based on the present lack of data
sufficient to meet the Fisheries Service's (OBIA) designation criteria,
even though NMFS' own experts acknowledged that (f)or much of the
world's oceans, data on cetacean distribution or density do not
exist.'' NRDC v. Pritzker, 828 F.3d at 1142. Although the White Paper
authors utilized the term ``biological importance'' in the title of the
paper, they clearly stated that ``it must be decided whether the list
of OBIAs should be comprehensive (based on a `precautionary approach')
or pure (based on the `minimalist approach'),'' and explicitly declined
to provide an answer to this question. Specifically, they indicated
``it must be decided whether to be precautionary and possibly nominate
areas that are of marginal importance in an attempt to minimize the
chances of overlooking biologically important areas'' or ``minimize the
chances of nominating sites that are of marginal biological importance
and, therefore, risk overlooking biologically important areas.'' Then,
the authors suggested three general recommendations for decision making
based upon a precautionary approach if that is the method selected by
the decision maker, as discussed further below.
However, the recommendations of the White Paper present a
dichotomous ``precautionary versus non-precautionary'' choice, an
interpretation that fails to consider the context of the requirements
of the MMPA, the nature of the anticipated effects of the action at
issue, and the other mitigation measures. More appropriately, NMFS has
fully and independently considered each of the White Paper's three
recommendedations in the context of the MMPA's LPAI standard, as
described below. In that analysis, we first note the small scale of the
anticipated effects of the Navy's request for authorization (496-592
hours/year of SURTASS LFA sonar spread across two ocean basins) and the
low magnitude and severity of impacts expected to any individual marine
mammals (relatively short-term exposures given the spatial scale of the
vessels' movement), even in the absence of mitigation, given the nature
of the activities. Then we note the robust shutdown measures that
utilize the highly effective visual, passive acoustic, and active
acoustic detection methods that are in place for all areas and times to
avoid marine mammal injury as well as minimize TTS and more severe
behavioral responses, belying claims that we treat data-poor areas as
though they are equivalent to zero-density areas or areas of no
biological importance. Next, we discuss the coastal standoff zone,
which minimizes take of many species with coastal habitat preferences.
We then examine the activity restrictions in OBIAs, which further limit
potentially more significant impacts in areas that are known to be
biologically important to the species that are more susceptible to the
SURTASS LFA sonar signal. Finally, we discuss the limited and uncertain
additional protective value that the White Paper recommendations would
be expected to provide for marine mammal individuals, much less species
or stocks. After considering all of this information, in addition to
the information provided by the Navy indicating that further
restricting SURTASS LFA sonar training and testing in the areas
recommended in the White Paper would be impracticable, NMFS determined
that the use of the White Paper recommendations was not appropriate.
White Paper Specific Recommendations
While the White Paper authors essentially disqualified the specific
extrapolative predictive results of the Kaschner model based on ground-
truthing them against known data, they nevertheless recommended broader
protections based on fewer environmental variables, to be used if NMFS
determined that a ``precautionary approach'' was appropriate. Although
the current White Paper recommendations are grounded in some sound
broad ecological principles, the ``precautionary approach'' considered
by the White Paper authors potentially suffers from some of the same
types of weaknesses as the Kaschner model or other ``environmental
envelope'' precautionary approaches. In the 2012 SURTASS LFA sonar
rule, NMFS evaluated the White Paper solely through the lens of the
OBIA process, and determined that the recommendations presented were
not appropriate for identification of OBIAs, which may have limited
fuller consideration of the recommendation. For this rulemaking, NMFS
independently examined the White Paper's specific recommendations in
the context of the LPAI standard to determine whether following those
recommendations is warranted to minimize the impacts from SURTASS LFA
sonar training and testing activities on the affected marine mammal
species or stocks. This consideration was done outside of the OBIA
designation process, and is consistent with the consideration of
criteria described above when determining appropriateness of mitigation
measures. The White Paper recommended the following general guidelines
based on ecological principles to identify areas of biological
importance for cetaceans:
(1) Designation of all continental shelf waters and waters 100 km
seaward of the continental slope as biologically important habitat for
marine mammals;
(2) Establishment of OBIAs within 100 km of all islands and
seamounts that rise within 500 m of the surface; and
(3) Nomination of high productivity regions that are not included
in the continental shelf, continental slope, seamount, and island
ecosystems above as biologically important areas.
These recommendations are evaluated below in the context of the
proposed SURTASS LFA sonar training and testing activities and the
mitigation measures that have been and are proposed to be implemented
to minimize the impacts on the affected marine mammal species or stocks
from these activities.
To reiterate, NMFS has required several mitigation measures for
SURTASS LFA training and testing sonar activities that: (1) Minimize or
alleviate the likelihood of injury (PTS), TTS, and more severe
behavioral responses (the 2,000-yard LFA mitigation/buffer zone)); (2)
additionally minimize or avoid behavioral impacts in known important
areas (which includes important habitat) that would have a higher
potential to have negative energetic effects or deleterious effects on
reproduction that could reduce the likelihood of survival or
reproductive success (OBIAs); and (3) generally lessen the total number
of takes of many species with coastal or shelf habitat preferences
(coastal standoff). The nature and context of how LFA sonar is used in
training and testing activities (small number of vessels operating in
open ocean areas and typically using active sonar only sporadically) is
such that impacts to any individual are expected to be limited
primarily because of the short duration of exposure to any individual
mammal. In addition, as explained above, an animal would need to be
fairly close to the source for the entire length of a transmission (60
seconds) to experience
[[Page 7242]]
injury, and exposures occur in open water areas where animals can more
readily avoid the source and find alternate habitat relatively easily.
In addition, highly effective mitigation measures would be implemented
that further ensure impacts are limited to lower-level responses with
limited potential to significantly alter natural behavior patterns in
ways that would affect the fitness of individuals and by extension the
affected species or stocks.
SURTASS LFA sonar operates at 100 to 500 Hz. This frequency is far
below the best hearing sensitivity for MF and HF species. HF species
have their best hearing between around 60 and 125 kHz, which means that
a sound at 500 Hz (and below) has to be at least 50 dB louder for HF
species to hear it as well as a sound in their best hearing range. MF
cetaceans have their best hearing between around 40 and 80 kHz, which
means that at 500 Hz and below, the sound has to be 40 dB louder, or
more, for this group to hear the sound as well as a sound in their best
hearing range. In other words, these species have to be much closer to
a sound at the frequency of SURTASS LFA sonar to hear it, which means
that generally they have to be much closer to the SURTASS sonar source
for it to cause PTS, TTS, or a behavioral response. Additionally,
during the 1997 to 1998 SURTASS LFA Sonar Low Frequency Sound
Scientific Research Program (LFS SRP), numerous odontocete species
(i.e., MF and HF hearing specialists) and pinniped species were sighted
in the vicinity of the sound exposure tests and showed no immediately
obvious responses or changes in sighting rates as a function of source
conditions, which likely produced received levels similar to those that
produced minor short-term behavioral responses in the baleen whales
(i.e., LF hearing specialists).
As described in the 2012 rule, NMFS believes that MF and HF
odontocete hearing specialists have such reduced sensitivity to the LFA
sonar source that limiting ensonification in OBIAs for those animals
would not afford meaningful protection beyond that which is already
incurred by implementing a shutdown when any marine mammal enters the
2,000-yard LFA mitigation/buffer zone. For the same reason, our
discussion of the White Paper recommendations will be limited to lower
frequency sensitive species, although it is worth noting that the
existing 22 km (14 mi; 12 nmi) coastal standoff ensures a reduced
number of potential takes of many MF and HF species with coastal
habitat preferences. Moreover, the White Paper's recommendations for
mitigation in data-poor areas were made solely for cetaceans.
As noted previously, in evaluating mitigation for species or stocks
and their habitat, we consider the expected benefits of the mitigation
measures for the species or stocks and their habitats against the
practicability of implementation. This consideration includes assessing
the manner in which, and the degree to which, the implementation of the
measure(s) is expected to reduce impacts to marine mammal species or
stocks (including through consideration of expected reduced impacts on
individuals), their habitat, and their availability for subsistence
uses (where relevant). This analysis will consider such things as the
nature of the proposed activity's adverse impact (likelihood, scope,
range); the likelihood that the measure will be effective if
implemented; the likelihood of successful implementation.
Practicability of implementing the measure is also assessed and may
involve consideration of such things as cost, impact on operations,
and, in the case of a military readiness activity, personnel safety,
practicality of implementation, and impact on the effectiveness of the
military readiness activity (16 U.S.C. 1371(a)(5)(A)(ii)).
Taking into account the above considerations, NMFS' evaluation of
the recommendations of the White Paper is described below:
Continental Shelf Waters and Waters 100 km Seaward of Continental Slope
Consideration of potential for reduction of adverse impacts to
marine mammal species and stocks and their habitat--The Navy already
implements a coastal standoff zone of 22 km (14 mi; 12 nmi), which
includes large parts of the continental shelf around the world,
includes parts of the slope in some areas, and reduces potential takes
of many marine mammal species and stocks with coastal habitat
preferences. In addition, under this SEIS/OEIS, the Navy is not able to
deploy and utilize SURTASS LFA sonar for training and testing within
any foreign nations territorial seas, which encompasses an area up to
12 nmi (depending on the distance each nation claims). The White Paper
provided little basis for the 100 km buffer seaward of the continental
slope and we have found no specific literature to support such a broad
buffer in all areas. Therefore, in the context of this evaluation, NMFS
first considered if there was evidence of the importance of the
continental slope itself, without any consideration for a buffer.
In support of understanding the additional value of expanding this
standoff to 100 km beyond the continental slope margin, NMFS assessed
known marine mammal density information for lower frequency hearing
specialists from the U.S. East (Roberts et al., 2016) and West coasts
and compared these densities to bathymetry, specifically looking at
areas of high densities compared to the continental shelf and slopes on
both coasts (NOAA, 2009). This assessment and comparison focused on the
U.S. East and West coasts as an example because relatively more data is
available for these waters. The comparison showed that mapped areas of
highest densities are not always related to the slope or shelf. For
example, while fin whales in the eastern U.S. waters show relatively
higher densities on the continental shelf and slope, relatively higher
densities of fin whales in western U.S. waters are much farther out to
sea from the continental shelf or slope (well beyond 100 km of the
slope), and the same was found for sperm whales. Some mysticetes do
show higher densities on the continental shelf, and some have higher
densities along the continental slope, which may also vary among
seasons (e.g., fin whales on the east coast). Generally, density
information from the Atlantic showed some enhanced densities along the
slope, but only for certain species in certain seasons, and did not
indicate universally high densities along the slope. There are many
factors that influence the spatial and temporal distribution and
abundance of cetaceans, including environmental variables such as
physiochemical, climatological, and geomorphological variables
operating on times scales ranging from less than a day to millennia;
biotic variables, such as prey distribution, competition among other
species, reproduction, and predation; and anthropogenic factors, such
as historical hunting, pollution, ship activity, etc. (Davis et al.,
1998). Humpback whales (especially around Cape Hatteras) seem to show
some higher densities around the slope, but also seaward of the slope,
especially in winters. However, the slope is closer to the shore around
Cape Hatteras than most places along the eastern seaboard, and while
humpbacks may show higher densities along the slope in this area, the
same cannot be said of humpbacks further south (i.e., in Florida) where
the slope is much further offshore. Right whales show higher densities
closer to shore along the Atlantic coast, while sperm whales are
farther out past the slope on the Atlantic coast, as they are deep
divers. Density data from the
[[Page 7243]]
Pacific coast show higher densities of blue whales on the shelf and
slope, while fin whales and sperm whales are observed in waters beyond
the continental slope. Gray whales show higher densities closer to
shore along the Pacific coast, while humpbacks seem to be along the
slope and beyond in some places. Using the continental United States
densities of these lower frequency sensitive species as examples showed
that densities are sometimes higher within 100 km of the slope, but are
often higher elsewhere (off the slope) and many of these high density
areas are highly seasonal.
As stated above, NMFS looked at these areas because relatively more
data are available and, since comparisons in these areas do not
consistently show strong correlation of high densities with the
continental slope, it is reasonable to infer the same inconsistent
relationship for other slope/shelf areas where there are even fewer
data. As discussed below, there is no scientific basis for NMFS to
conclude that geographical restrictions for these data-poor areas would
reduce adverse impacts to marine mammal species or stocks or their
habitat. Therefore, restricting SURTASS LFA sonar training and testing
activities within 100 km of the entire continental shelf and slope is
of questionable value as a mitigation measure to avoid areas of higher
densities of marine mammal species or stocks, and further, would
restrict these activities in large areas of the open ocean that we know
don't harbor high densities of marine mammals (especially when the 100-
km buffer is considered).
We said in the OBIA context that although we are identifying
``known'' biologically important areas, other biologically important
areas have yet to be identified, due to limited data. However, it is
important to realize that much more research is conducted close to
shore, in the United States and internationally, and typically areas
within 100 km of the slope are less likely to be data-poor compared to
other areas. In areas where there is extensive data on marine mammal
density and use (e.g., in the continental US EEZ), it may be
inappropriate to use broader principles that could be helpful in
identifying protected areas in data-poor areas. NOAA, Navy, other
agencies, and many independent researchers have been conducting marine
mammal research throughout the U.S. EEZ (200 mi from shore) for
decades. The prevalence of research makes it less likely that important
areas closer to shore have been overlooked.
NMFS acknowledges that large ocean areas such as the continental
shelf and slope and seamounts may include habitat features that could
provide important habitat for marine mammals at certain times--as the
White Paper states, the higher primary productivity in these areas
could generally be associated with higher densities of marine mammals.
However, exposures to any individual animal are expected to be short
term and intermittent, since a small number of ships would conduct
SURTASS LFA sonar training and testing activities for up to 496 hours
(years 1-4) and 592 hours (years 5-7) total for all ships combined
annually. In addition, shutdown measures would avoid injury (PTS), most
TTS, and severe behavioral responses, and coastal standoff zones and
OBIAs would avoid disturbances more likely to lead to fitness impacts
by further restricting activities in these areas of known biological
importance for marine mammals. Therefore, the other proposed mitigation
measures (which are currently in effect) would already limit most take
of marine mammals to less severe Level B harassment (e.g., short
periods of changes to swim speed or calling patterns; alterations of
dive profiles, etc.). As a result, there is little to no indication
that there is a risk to marine mammal species or stocks that would be
avoided or lessened if waters 100 km seaward of the continental slope
were subject to restrictions.
Of note, in many areas the waters of the continental shelf/slope
will be afforded significant protection due to the coastal standoff
mitigation measure. In addition, review of designated OBIAs reveals
that the majority include continental shelf/slope areas and similar
coastal waters. Therefore, to the extent that some portion of the
shelf/slope waters are important habitats, many are afforded protection
due to the geographical restrictions already in place (coastal standoff
and OBIAs), and NMFS has determined that the best available information
justifies these measures under our evaluation framework set forth
above.
Given the proposed mitigation measures, many of which are already
in place under the NDE and have been in effect for many years under
prior rules, takes of marine mammals would be limited to Level B
harassment in the less severe range of behavioral reactions and some
TTS, as described above. Consequently, the only additional anticipated
value to restricting activities in continental shelf waters and waters
100 km seaward of continental slope would be some, though not a
significant, reduction in the number of these less severe behavioral
reactions in those areas. As discussed above, in general, not all
behavioral responses rise to the level of a take and not all harassment
takes result in fitness consequences to individuals that have the
potential to translate to population consequences to the species or
stock. For example, the energetic costs of short-term intermittent
exposures to SURTASS LFA sonar (such as are expected here) would be
unlikely to affect the reproductive success or survivorship of
individuals. This means there is little to no likelihood that the
impacts of the anticipated takes would accrue in a manner that would
impact a species or stock even in the absence of any additional
mitigation. Therefore, considered with the uncertain potential of this
proposed recommendation to provide meaningful incremental reduction of
risk or severity of impacts to individual marine mammals, NMFS
concludes that this recommendation would not reasonably be expected to
provide a reduction in the probability or degree of effects on any
marine mammal species or stocks.
In addition to the mitigation measures in place for SURTASS LFA
sonar that would already provide protection for continental shelf/slope
waters, it is important to note that there are currently a total of
four SURTASS LFA sonar ships that would be training and testing with up
to a maximum of 496 transmission hours total, pooled across all
vessels, per year in years one through four. While the Navy plans to
add additional vessels beginning in year 5, the total transmission
hours would be capped at 592 hours total regardless of the number of
vessels. It is not known, nor does the Navy indicate in its plans, that
activities of these existing or proposed new vessels would be focused
in any specific area. It is likely, based on past monitoring reports,
that the activities of the multiple vessels are spatially separated and
not concentrated in a single area, and that they would not necessarily
overlap marine mammal high-density areas for an extended period of
time.
Consideration of practicability for restrictions in continental
shelf waters and waters 100 km seaward of continental slope--NMFS and
the Navy evaluated the practicability of implementation of the White
Paper's recommended continental shelf, slope, and 100-km seaward
restriction. The Navy has indicated, and NMFS concurs, that additional
continental shelf, slope, and 100 km seaward restrictions beyond the
territorial waters of foreign nations and the existing coastal standoff
and OBIAs would unacceptably impact the Navy's national security
mission, as large areas of the ocean would be
[[Page 7244]]
restricted where LFA sonar transmissions are required for training and
testing proficiency in order for the ships' crews to understand how the
system operates in these varied bathymetry conditions under future
operational scenarios.
The submarine forces of several key adversaries are rapidly growing
in size, capability, and geographic reach. Due to advancements in
quieting technologies in diesel-electric and nuclear submarines,
undersea threats are becoming increasingly difficult to locate using
traditional passive acoustic technologies. Submarines from many nations
are now much more capable and able to stay submerged for a longer
period of time than earlier vessels. For both conventional diesel-
electric and nuclear submarines, quieting technology has increased
stealth and thus operational effectiveness. These technologies include
air-independent propulsion (AIP), hull coatings that minimize echoes,
sound isolation mounts for machinery, and improved propeller design.
What once were unique U.S. design capabilities are now being employed
in new submarine projects and as upgrades to older submarines
throughout potential adversaries' navies. As this technology has
improved, the predominant sources of ship noise (for example propeller
noise or other machinery noise) have been reduced. Passive sonar
involves listening for sounds emitted by a potentially hostile
submarine in order to detect, localize, and track it. As submarines
become quieter through improved sound dampening technology and
innovative propeller design, the usefulness of passive sonar systems
has greatly diminished. These submarines have the ability to carry many
different weapons systems, including torpedoes, long-range anti-ship
cruise missiles, anti-helicopter missiles, anti-ship mines, and
ballistic nuclear missiles. These capabilities make submarines, both
nuclear and diesel-electric powered, stealthy and flexible strategic
threats.
The destruction of U.S. Carrier Strike Groups (CSGs) and
Expeditionary Strike Groups (ESGs) is a focal point in the naval
warfare doctrine of many adversaries' navies. The main threat that a
carrier strike group must defend against is the undersea threat from
enemy submarines. A single diesel-electric submarine that is capable of
penetrating U.S. or multinational task force defenses could cause
catastrophic damage to those forces, and jeopardize the lives of the
thousands of Sailors and Marines onboard Navy ships. Even the threat of
the presence of a quiet diesel submarine could effectively deny or
delay U.S. or coalition naval forces access to vital operational areas.
Long-range detection of threat submarines in near-shore and open ocean
environments is critical for this effort.
Adequate and effective training and testing with SURTASS LFA sonar
is necessary to ensure crews can operationally detect these quieter and
harder to-find foreign submarines at greater distances. The Navy has
indicated that if large areas of the continental shelf or slope were
restricted beyond what is in the 12nmi/22km coastal standoff, the Navy
would not have the benefit of being able to train and test in these
challenging environments. Coastal, shallow environments are more
acoustically complex and the SURTASS LFA system was designed to
penetrate these environments to find quiet assets that may use these
distinctive geographic features to their advantage. Year-round access
to all of these areas of challenging topography and bathymetry is
necessary so that crews learn how the SURTASS LFA system will operate
amidst changing oceanographic conditions, including seasonal variations
that occur in sound propagation.
Because these assets are forward deployed and can rapidly switch
between training and testing activities and operational missions, there
is limited flexibility for these ships to maneuver any substantial
distance from primary mission areas of responsibility. Therefore,
avoiding continental shelf and slope waters plus a 100 km buffer for
training and testing activities would constitute a significant
deviation in their staging requirements for other missions. Thus
implementing this mitigation measure would be highly impracticable and
would significantly adversely affect the availability of these assets
to conduct their national security mission. Additionally, due to the
slow speed at which these vessels transit (3 knots when towing SURTASS,
10-12 knots without) it does not allow for large scale movements on the
orders of 100s of km proposed by the mitigation scheme of the White
Paper to avoid a 100 km buffer around continental shelf and slope
habitat.
Conclusion regarding restrictions in continental shelf waters and
waters 100 km seaward of continental slope--In summary, restricting
SURTASS LFA sonar use in waters 100 km seaward from the continental
slope could potentially reduce individual exposures or behavioral
responses for certain species and potentially provide some additional
protection to individual animals in preferred habitat in some cases.
However, density data indicate that certain mysticetes and sperm whales
have higher densities in areas other than the continental slope and
potential impacts from moving and focusing activities farther offshore
would shift from more coastal species or stocks to more pelagic species
or stocks, making any reduction in impacts uncertain. Further, limiting
activities in these large areas of uncertain value to marine mammals
when activities are comparatively low (small number of ships operating
up to a maximum of 496 transmission hours total across all vessels in
years 1-4 and 592 total transmission hours in years 5 and beyond pooled
across all vessels, spread across several mission areas and over the
course of an entire year), given the existing risks to the affected
species and stocks are already so low, would provide little, if any,
value for lowering the probability or severity of impacts to individual
marine mammal fitness, much less species or stocks, or their habitat.
Given the limited potential for additional reduction of impacts to
marine mammal species beyond what the existing mitigation measures
described in this rule provide, and the high degree of impracticability
(significant impacts on training and testing effectiveness and the
availability of these assets to support other national security
missions), NMFS has preliminarily determined that adopting this
recommendation is not warranted under the LPAI standard.
Restrictions Within 100 km of All Islands and Seamounts That Rise to
Within 500 m of the Surface
Consideration of potential reduction of adverse impacts to marine
mammal species and stocks and their habitat--Currently, waters
surrounding all islands are included in the coastal standoff zone.
Also, all foreign territorial waters have been provided the additional
protection in this rulemaking that SURTASS LFA sonar will not be
operated within these areas. As discussed previously, this means that
SURTASS LFA sonar received levels would not exceed 180 dB re 1[micro]Pa
within 22 km (12 nmi) from the coastline. Lastly, the Navy has agreed
not to utilize SURTASS LFA sonar within Hawaii state waters (out to 3
nmi) or over Penguin Bank, and to limit ensonification of Hawaii state
waters to 145 dB.
Regarding seamounts, Morato et al. (2010) state that seamounts were
found to have higher species diversity within 30-40 km of the summit
and tended to aggregate some visitor species (Morato
[[Page 7245]]
et al., 2008). However, as stated by the authors, the paper did not
demonstrate that this behavior can be generalized. Further, the authors
note that associations with seamounts have been described for some
species of marine mammals (Morato et al., 2008), mostly on an
individual seamount scale. Morato et al. (2008) examined seamounts for
their effect on aggregating visitors and noted that seamounts may act
as feeding stations for some visitors, but not all seamounts seem to be
equally important for these associations. While Morato et al. (2008)
only examined seamounts in the Azores, the authors noted that only
seamounts shallower than 400 m depth showed significant aggregation
effects. Their results indicated that some marine predators (common
dolphin (Delphinus delphis) and other non-marine mammal species such as
fish and invertebrates) were significantly more abundant in the
vicinity of some shallow-water seamount summits; there was no
demonstrated seamount association for bottlenose dolphins (Tursiops
truncatus), spotted dolphin (Stenella frontalis), or sperm whales
(Physeter macrocephalus).
Along the northeastern U.S. continental shelf, cetaceans tend to
frequent regions based on food preferences (i.e., areas where preferred
prey aggregate), with picscivores (fish-eating, e.g., humpback, fin,
and minke whales as well as bottlenose, Atlantic white-sided, and
common dolphins) being most abundant over shallow banks in the western
Gulf of Maine and mid-shelf east of Chesapeake Bay; planktivores
(plankton-eating, e.g., right, blue, and sei whales) being most
abundant in the western Gulf of Maine and over the western and southern
portions of Georges Bank; and teuthivores (squid eaters, e.g., sperm
whales) most abundant at the shelf edge (Fiedler, 2002). While there
have been observations of humpback whales lingering at seamounts in the
middle of the North Pacific on the way to summer feeding grounds in the
Gulf of Alaska (Mate et al., 2007), the purpose of these occurrences is
not clear, and it may be that they are feeding, regrouping, or simply
using them for navigation (Fiedler, 2002; Mate et al., 2007);
therefore, the role of the seamount habitat is not clear. According to
Pitcher et al. (2007), there have been very few observations of high
phytoplankton biomass (i.e., high primary production, usually estimated
from chlorophyll concentrations) over seamounts. Where such effects
have been reported, all were from seamounts with summits shallower than
300 m, and the effects were not persistent, lasting only a few days at
most. Therefore, it may be that food sources for many baleen whales are
not concentrated in great enough quantities for significant enough time
periods to serve as important feeding areas. While some odontocete
(toothed) whales have been suggested to utilize seamount features for
prey capture (Pitcher et al., 2007), the authors conclude that the
available evidence suggests that ``unlike many other members of
seamount communities, the vast majority of marine mammal species are
probably only loosely associated with particular seamounts.'' We note
here that marine mammals being ``loosely associated'' with seamounts,
or being observed lingering at certain seamounts, does not necessarily
suggest a level of biological importance that would support
geographical restrictions to avoid all seamounts, or even the specific
seamounts where these loose aggregations occur. Further, as stated
above, the short term, intermittent nature of the exposures to SURTASS
LFA sonar would be unlikely to impact the fitness (via effects on
reproduction or survival) of any individuals, especially given the
existing/proposed mitigation. Therefore, considered with the uncertain
potential of this proposed measure to provide meaningful additional
reduction of impacts to individual marine mammals, this measure is not
expected to provide a reduction in the probability or degree of effects
on any marine mammal species or stocks.
Consideration of practicability for restrictions within 100 km of
all islands and seamounts that rise to within 500 m of the surface--
Please see the discussion of practicability for the White Paper
recommendation above (protection of continental slope and a 100-km
buffer), which is also applicable here. NMFS and the Navy evaluated the
practicability of implementation of the White Paper's recommendation
regarding island and seamounts that rise to within 500 m of the sea
surface. The Navy has indicated, and NMFS concurs, that restrictions
within 100 km of all islands and seamounts that rise to within 500 m of
the surface beyond the existing coastal standoff and OBIAs would
unacceptably impact their national security mission. Adequate and
effective training and testing with SURTASS LFA is necessary to ensure
crews can operationally detect quieter and harder to-find foreign
submarines at greater distances. The Navy has indicated that if large
areas of the continental shelf or slope were restricted beyond what is
in the 12nmi/22km coastal standoff, the Navy would not have the benefit
of being able to train and test in these challenging environments.
Coastal, shallow environments are more acoustically complex and the
SURTASS LFA system was designed to penetrate these environments to find
quiet assets that may use these distinctive geographic features to
their advantage. Year-round access to all of these areas of challenging
topography and bathymetry is necessary so that crews learn how the
SURTASS LFA system will operate amidst changing oceanographic
conditions, including seasonal variations that occur in sound
propagation.
As discussed previously with respect to a 100 km buffer around
continental shelf and slope habitat, similar practicability concerns
exist with implementing a 100 km buffer around all islands and
seamounts. Because these assets are forward deployed and can rapidly
switch between training and testing activities and operational
missions, there is limited flexibility for these ships to maneuver any
substantial distance from their primary mission areas of
responsibility. Since seamounts and other areas of complex bathymetry
are important training/testing features avoiding these areas would have
negative impacts on training and testing preparedness and realism.
Additionally, avoiding island associated and sea mount habitats by 100
km would constitute a significant deviation in the staging of these
assets for other missions and would significantly impacting their
potential for these vessels to conduct operational missions. Lastly,
due to the slow speed at which these vessels transit (3 knots when
towing SURTASS, 10-12 knots without) it does not allow for large scale
movements on the orders of a 100 km proposed by the mitigation scheme
of the White Paper without requiring extensive transmit time on and off
station that would reduce training and testing opportunities and the
ability of these assets to support other national security missions
required of them.
Conclusion regarding restrictions within 100 km of all islands and
seamounts that rise to within 500 m of the surface--In summary, while
restricting LFA sonar training and testing in areas 100 km seaward from
islands and seamounts could potentially reduce incidences of take
within a limited number of species in preferred habitat in some cases
(potential feeding), available data indicate that marine mammal
associations with these areas are limited and the benefits would
[[Page 7246]]
be at best limited and/or ephemeral. Also, the habitat preferences for
these areas seem to be more associated with mid and high frequency
species, which are less sensitive to LFA sonar, thereby further
lessening concern for the potential effects of LFA sonar. Limiting
SURTASS LFA sonar training and testing activities in these large areas
when activities are already comparatively low (small number of ships
operating up to a maximum of 496 transmission hours total across all
vessels in years 1-4 and 592 total transmission hours in years 5 and
beyond pooled across all vessels, spread across several mission areas
and over the course of an entire year) and the existing risks to the
affected species and stocks are already so low, would provide little,
if any, value for lowering the probability or severity of impacts to
individual marine mammal fitness, much less species or stocks, or their
habitat. Given the limited potential for additional reduction of
impacts to a small number of marine mammal species and the high degree
of impracticability (serious impacts on mission effectiveness), NMFS
has determined that adopting this recommendation is not warranted under
the LPAI standard.
High Productivity Regions That Are Not Included in the Continental
Shelf, Continental Slope, Seamount, and Island Ecosystems
Consideration of potential for reduction of adverse impacts to
marine mammal species and stocks and their habitat--Regions of high
productivity have the potential to provide good foraging habitat for
some species of marine mammals at certain times of the year and could
potentially correlate with either higher densities and/or feeding
behaviors through parts of their area. Productive areas of the ocean
are difficult to consistently define due to interannual spatial and
temporal variability. High productivity areas have ephemeral boundaries
that are difficult to define and do not always persist interannually or
within the same defined region. While there is not one definitive guide
to the productive areas of the oceans, NMFS and the Navy examined these
areas in the SURTASS LFA sonar study area. For instance, Huston and
Wolverton (2009) show areas of high/highest productivity that are
either (1) confined to high latitude (polar) areas that are not in the
SURTASS LFA sonar study area, or (2) very coastally and typically
seasonally associated with areas of high coastal runoff (i.e., by river
mouths), which are already encompassed by the coastal standoff range.
Areas of more moderate productivity are typically very large, which
means that they are not concentrating high densities or feeding areas
throughout their area. In fact, areas of moderate productivity scored
within the mean and thus represent ``average'' habitat and would not
necessarily be biologically important. These moderately productive
habitats are likely to provide ample alternative opportunities for
species to move into and take advantage of areas should they avoid the
area around the SURTASS LFA sonar vessel. Additionally, as noted above,
given the nature of SURTASS LFA sonar activities and the other
mitigation for SURTASS LFA sonar, the existing risk to marine mammal
species and stocks is low and is limited to less severe Level B
harassment.
Consideration of practicability for restrictions for high
productivity regions that are not included in the continental shelf,
continental slope, seamount, and island ecosystems--NMFS and the Navy
evaluated the practicability of implementation of the White Paper's
recommended restrictions on high productivity areas. Please see the
discussion of practicability for the first white paper recommendation
above (continental slope plus buffer), which is also applicable here.
The Navy has indicated, and NMFS concurs, that, additional restrictions
in high productivity regions that are not included in the continental
shelf, continental slope, seamount, and island ecosystems beyond the
existing coastal standoff and OBIAs would unacceptably impact its
national security mission. Because of the inconsistent and ephemeral
boundaries associated with most high productivity regions, it would be
difficult to define geographic restrictions that would not impinge upon
the long-range detection abilities of the SURTASS LFA sonar system. The
mission of SURTASS LFA sonar is to detect quieter and harder-to-find
foreign submarines at greater distances. The Navy must train and test
in open ocean regions to track relevant targets at long distances. If
large areas of the ocean were excluded from potential usage, the Navy
would not have the benefit of being able to train and test at the long
ranges at which SURTASS LFA sonar has been designed to function most
effectively. Further, because high productivity areas are highly
variable and ephemeral, implementation would not be operationally
practicable for the Navy.
Conclusion regarding restrictions in high productivity regions that
are not included in the continental shelf, continental slope, seamount,
and island ecosystems--Restricting use of SURTASS LFA sonar training
and testing seasonally in high productivity areas could potentially
reduce take numbers for certain species in preferred or feeding habitat
in some cases. However, as noted above, the size of the primary
productivity areas is such that animals could likely easily access
adjacent high productivity areas should they be temporarily diverted
away from a particular area due to a SURTASS LFA sonar source. In
addition, marine mammals are not concentrated through all, or even
most, of these large areas for all, or even most, of the time when
productivity is highest. Therefore, a broad limitation of this nature
would likely unnecessarily limit LFA sonar activities while providing
only some slight benefit to a limited number of individuals, which
would not rise to the level of value to marine mammal species or
stocks. Limiting activities in these large areas when activities are
already comparatively low (small number of ships operating up to a
maximum of 496 transmission hours total across all vessels in years 1-4
and 592 total transmission hours in years 5 and beyond pooled across
all vessels, spread across several mission areas and over the course of
an entire year), given the existing risks to the affected species and
stocks are already so low, would provide little, if any, value for
lowering the probability or severity of impacts to individual marine
mammal fitness, much less species or stocks, or their habitat. While we
note that subjecting entire ``high productivity regions'' to
geographical restrictions would provide little value, we also reiterate
that over half of the existing OBIAs previously identified are in areas
categorized as Class I (high productivity, >300 gC/m2-yr) or Class II
(moderate productivity, 150-300 gC/m2-yr) ecosystems, based on SeaWiFS
global primary productivity (see response to NRDC comment 20, 77 FR
50290, 50304 (August 20, 2012)). However, we also note that high
productivity/foraging was not necessarily the qualifying criteria for
all of these OBIAs, and being classified as a high productivity area
does not necessarily mean the area serves as a biologically important
area for marine mammal foraging. Given the limited potential for
additional reduction of impacts to marine mammal species and the high
degree of impracticability (serious impacts on mission effectiveness),
NMFS has determined that adopting this recommendation is not warranted
under the LPAI standard.
[[Page 7247]]
Overall Conclusion Regarding Consideration of the White Paper
Recommendations
NMFS has considered the White Paper recommendations and
acknowledges that they could potentially reduce the numbers of take for
some individual marine mammals within a limited number of species,
while in some cases, adopting the White Paper's guidelines could
potentially increasing take of others species. NMFS also acknowledges
that the White Paper's recommendations may add some small degree of
protection in preferred habitat or during feeding behaviors in certain
circumstances. However, the potential for impacts on reproduction or
survival of any individuals, much less accrual to population level
impacts, with the existing mitigation is already very low. As explained
above, the minimal training and testing impacts and the anticipated,
and demonstrated, success of the significant mitigation measures that
the Navy is already implementing provide a large degree of protection
and limit takes to less severe Level B harassment. Therefore, the
highly limited and uncertain likelihood that the White Paper
recommendations will further reduce impacts on individual marine mammal
fitness, much less the affected species or stocks, and their habitat
does not justify adopting the recommendations, especially when
considered in light of the high degree of impracticability for Navy
implementation.
Least Practicable Adverse Impact--Preliminary Conclusions
Based on our evaluation of the Navy's proposed mitigation measures
as well as other measures considered by NMFS or recommended by the
public, NMFS has preliminarily determined that the mitigation measures
required by this proposed rule provide the means of effecting the least
practicable adverse impact on marine mammals, species, or stock(s) and
their habitat, paying particular attention to rookeries, mating
grounds, and areas of similar significance, considering personnel
safety, practicality of implementation, and impact on the effectiveness
of the military readiness activity.
The 2,000-yard LFA mitigation/buffer (shutdown) zone, based on
detection of marine mammals from the highly effective three-part
mitigation monitoring efforts (visual, as well as active and passive
acoustic monitoring), and geographic restrictions (coastal standoff
zone, and OBIAs plus the 1-km buffer) will enable the Navy to: (1)
Avoid Level A harassment of marine mammals; (2) minimize the incidences
of marine mammals exposed to SURTASS LFA sonar sound levels associated
with TTS and more severe behavioral effects under Level B harassment;
and (3) minimize marine mammal takes in areas and during times of
important behaviors such as feeding, migrating, calving, or breeding or
in areas where small resident populations reside or there is high
density, further minimizing the likelihood of adverse impacts to
species or stocks.
The SURTASS LFA sonar signal is not expected to cause mortality,
serious injury, or PTS, due to implementation of the 2,000-yard LFA
sonar mitigation/buffer zone, which will ensure that no marine mammals
are exposed to an SPL greater than about 174 dB re: 1 [micro]Pa rms. As
discussed above, a low-frequency cetacean would need to remain within
41 meters (135 ft) for an entire LFA sonar transmission (60 seconds) to
potentially experience PTS and within 413 m (1,345 ft) for an entire
LFA sonar transmission (60 seconds) to potentially experience TTS,
which would be unlikely given typical avoidance behaviors even in the
absence of mitigation. In addition to alleviating the likelihood of
PTS, the implementation of the 2,000-yard LFA sonar shutdown zone
mitigation measure will minimize the number of LF cetaceans likely
exposed to LFA sonar at levels associated with the onset of TTS. The
best information available indicates that effects from SPLs less than
180 dB re: 1 [micro]Pa will be limited to short-term, Level B
harassment, and animals are expected to return to behaviors shortly
after exposure.
Further, the implementation of OBIA measures and the coastal
standoff allows the Navy to minimize or avoid impacts in important
areas where behavioral disturbance and other impacts would be more
likely to have negative energetic effects, or deleterious effects on
reproduction, which could reduce the likelihood of survival or
reproductive success (measures to avoid or lessen exposures of marine
mammals within the coastal standoff zone and OBIAs); and generally
lessen the total number of takes in areas of higher density for some
species (coastal standoff measures). These measures, taken together,
constitute the means of effecting the least practicable adverse impact
on the affected species and stocks in the western and central North
Pacific and eastern Indian Oceans in the upcoming seven-year LOA
period. As described above, we evaluated the potential inclusion of
additional measures (White Paper recommendations, critical habitat,
etc.) before reaching this conclusion.
The SURTASS DSEIS/SOEIS evaluated the potential for impacts to
marine habitats (marine mammals and otherwise) from SURTASS LFA sonar
training and testing activities including critical habitat, essential
fish habitat, marine protected areas, and national marine sanctuaries.
SURTASS LFA sonar training and testing activities involve introduction
of pressure and sound in the water column but will not alter physical
habitat. Marine mammal prey will not be exposed to sustained duration
and intensity of sound levels that would be expected to result in
significant adverse effects to marine mammal food resources. Habitat
impacts were considered within the context of the addition of sound
energy to the marine environment while SURTASS LFA sonar is
transmitting, which represents a vanishingly small percentage of the
overall annual underwater acoustic energy budget that would not affect
the ambient noise environment of marine habitats (refer to sections 4.4
and 4.5 of the SURTASS DSEIS/SOEIS). Therefore, with regard to habitat,
NMFS has not identified any impacts to habitat from SURTASS LFA sonar
that persist beyond the time and space that the impacts to marine
mammals themselves and the water column could occur. Our mitigation
targeted to minimize impacts to species or stocks while in particular
habitats (i.e., the coastal standoff and OBIAs) will protect preferred
habitat during its use, and therefore is contributing to the means of
effecting the LPAI on a species or stock and its habitat. Therefore,
the mitigation measures that address areas that serve as important
habitat for marine mammals in all or part of the year help effectuate
the LPAI on marine mammal species and stocks and their habitat.
The Ninth Circuit's Pritzker decision faulted NMFS for considering
the White Paper mitigation recommendations for ``data-poor areas''
against the OBIA standards NMFS had set for the 2012 rule. We do not
read the opinion as holding that the MMPA compelled a change in the
criteria and process for evaluating OBIAs. NMFS addressed the Court's
decision by separately and independently evaluating the White Paper's
recommendations for benefits to the affected species or stocks and
practicability, without regard to the OBIA criteria or process. (See
NMFS' evaluation of the White Paper in this rule.) Using the best
available information, NMFS considered the recommendations in the White
Paper under our interpretation of the LPAI
[[Page 7248]]
standard and determined the measures (as well as a smaller buffer
distance) were not warranted, as described in that section.
In reaching the conclusion that NMFS' record for the 2012 rule did
not establish the agency had satisfied the LPAI standard, the Court
determined that NMFS failed to consider an important aspect of the
problem, ``namely the underprotection that accompanies making
conclusive data an indispensable component of OBIA designation,'' and
that this ``systematic underprotection of marine mammals'' cannot be
consistent with the requirement that mitigation measures result in the
``least practicable adverse impact'' on marine mammals.'' Id. at 1140.
While we have corrected the identified deficiency by evaluating the
White Paper measures independent of the OBIA process, we disagree with
the suggestion that our mitigation is systematically underprotective.
We first emphasize that NMFS' OBIA informational standards (and
other mitigation measures), while data-driven, do not require
scientific certainty or conclusive data. This is illustrated by the
fact that the OBIA screening criteria allow for consideration of a
variety of information sources, including historic whaling data,
stranding data, sightings information, and regional expertise, to name
a few examples of the ``data'' considered--and, in fact, the only areas
that were not considered were those considered to have entirely
inconclusive data. As more detailed in Appendix D of the 2012 SEIS/
SOEIS, supporting documents that are considered include peer-reviewed
articles; scientific committee reports; cruise reports or transects;
personal communications or unpublished reports; dissertations or
theses; books, government reports, or NGO reports; and notes,
abstracts, and conference proceedings. The process set up for the 2012
rule carried forward areas for consideration if they had sufficient
scientific support for the relevant criterion based on a ranking of 2
or higher on a scale developed for that purpose, with zero being the
lowest and four the highest. Even areas that were ranked ``2''
(``Supporting information derived from habitat suitability models (non-
peer reviewed), expert opinion, regional expertise, or gray (non-peer
reviewed) literature, but requires more justification'') were deemed
``eligible'' for further consideration (77 FR 50290, 50299 (August 20,
2012)).
In fact, NMFS has previously designated OBIAs for areas based on
these types of information sources. For example, the Olympic Coast OBIA
(OBIA #21) had a ranking of 2 for foraging by humpback whales as
documented in one peer-reviewed report (p.D-319, DoN 2012). Based on
the results of that study, the Olympic Coast OBIA was reviewed and
designated. Other examples include the Southwest Australia Canyons
OBIA, which considers past whaling data but also more recent sighting
and stranding information; and the boundary for the Eastern Gulf of
Mexico OBIA, which was drawn to ``conservatively encompass'' waters
where Bryde's whales may occur based on sightings information (as
opposed to scientific validation of their occurrence). In addition,
even though most available data is only available for inshore waters
(within the coastal standoff for SURTASS LFA sonar training and testing
activities), NMFS is considering an area adjacent and seaward of these
areas in the Ogasawara Island region as an OBIA as part of this
rulemaking due to the importance of the nearshore area for humpback
whales.
Thus, NMFS does not insist on an ``unattainable'' evidentiary
standard of ``conclusive data'' \5\ for imposing conservation and
management measures for SURTASS LFA sonar, including--though not only--
in the case of OBIAs. As another example, the coastal standoff zone
uniformly applies not only in areas with supporting data about marine
mammals (80 percent of the areas initially identified for OBIA
consideration were within the 12 nmi/22 km coastal standoff) but also
in areas that could be fairly characterized as data poor.
---------------------------------------------------------------------------
\5\ NRDC v. Pritzker, 828 F.3d 1125, 1140 (9th Cir. 2016).
---------------------------------------------------------------------------
Finally, because the LPAI standard authorizes NMFS to weigh a
variety of factors when evaluating appropriate mitigation measures, it
does not compel mitigation for every kind of individual take, even when
practicable for implementation by the applicant. Thus, we do not
evaluate measures strictly on the basis of whether they will reduce
taking. The focus is on the relevant contextual factors that more
meaningfully assess a measure's value in contributing to the standard
of minimizing impacts to the affected species or stock and its habitat.
It is also relevant to consider a measure in the context of the nature
and extent of the expected impacts and the value of other mitigation
that will be implemented.
NMFS has evaluated the likely effects of SURTASS LFA sonar training
and testing activities and has required measures to minimize the
impacts to the affected species or stocks and their habitat to achieve
the LPAI. Consistent with our interpretation of LPAI, the LFA shutdown
and coastal exclusion zone are practicable for the Navy and effective
in minimizing impacts on marine mammals from activities that are likely
to increase the probability or severity of population level effects--
wherever marine mammals occur, even in areas where data are limited.
Therefore, as we have said, NMFS' mitigation requirements do not
proceed as if the ``no data'' scenario is the equivalent to ``zero
population density'' or ``no biological importance.'' \6\ The LFA
shutdown zone will avoid or minimize auditory impacts and more severe
forms of Level B harassment, wherever marine mammals occur. The coastal
exclusion zone will reduce adverse impacts, specifically higher numbers
of take or take in areas of preferred habitat for coastal species that
are present in higher numbers, or through lessening the severity of
impacts by minimizing take of individuals in shelf or slope areas
encompassed by the standoff, when that habitat is preferred by some
species (again, when NMFS assessed areas that met the criteria for
OBIAs for its 2012 rule, 80 percent of the identified areas fell within
the 12 nautical mi coastal exclusion zone.) In addition, NMFS
designated OBIAs where supporting information sufficiently demonstrated
the areas met the established criteria and they were determined to be
practicable, which are expected to reduce the likelihood of impacts
that would adversely affect reproduction or survival.
---------------------------------------------------------------------------
\6\ White paper at p. 1.
---------------------------------------------------------------------------
We have assessed all recommendations and the best available science
and are aware of no other practicable measures that would further
reduce the probability of impacts to species or stocks. In other words,
the proposed measures that NMFS included in this proposed rule will
effect the least practicable adverse impact on the affected species or
stocks. As discussed in the Adaptive Management section, NMFS will
systematically consider new information and re-evaluate as necessary if
applicable new information becomes available.
Proposed Monitoring
Section 101(a)(5)(A) of the MMPA states that in order to issue an
ITA 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 LOAs
must include the suggested means of
[[Page 7249]]
accomplishing the necessary monitoring and reporting that will result
in increased knowledge of the species, the level of taking, or impacts
on populations of marine mammals that are expected to be present.
Monitoring measures prescribed by NMFS should accomplish one or
more of the following general goals:
An increase in our understanding of how many marine
mammals are likely to be exposed to levels of LFA sonar that we
associate with specific adverse effects, such as disruption of
behavioral patterns and TTS (Level B harassment), or PTS;
An increase in our understanding of how individual marine
mammals respond (behaviorally or physiologically) to LFA sonar (at
specific received levels or other stimuli expected to result in take);
An increase in our understanding of how anticipated takes
of individuals (in different ways and to varying degrees) may impact
the population, species, or stock (specifically through effects on
annual rates of recruitment or survival);
An increase in knowledge of the affected species;
An increase in our understanding of the effectiveness of
certain mitigation and monitoring measures;
A better understanding and record of the manner in which
the authorized entity complies with the incidental take authorization;
and
An increase in the probability of detecting marine
mammals, both within the mitigation zone (thus allowing for more
effective implementation of the mitigation) and in general to better
achieve the above goals.
In addition to the real-time monitoring associated with mitigation,
the Navy is engaging in exploring other monitoring efforts described
here:
Marine Mammal Monitoring (M3) Program
Beginning in 1993, the Marine Mammal Monitoring (M3) Program was
designed to assess the feasibility of detecting and tracking marine
mammals. The M3 program uses the Navy's fixed and mobile passive
acoustic monitoring systems to monitor the movements of some large
cetaceans (principally baleen whales), including their migration and
feeding patterns, by tracking them through their vocalizations. This
Program has evolved into a valuable tool by which the acoustic activity
levels of vocalizing whales can be quantitatively documented and trends
of oceanic ocean noise levels measured over ecologically meaningful
ocean scales and time periods under varying noise conditions.
As part of the research and monitoring component of the SURTASS LFA
sonar program, M3 data are collected to:
Document occurrence, distribution, and behaviors of
acoustically active whale species over ocean basin and decadal scales;
Assess changes in marine mammal activity levels under
normal conditions (e.g., weather, wind, time of year, or time of day)
relative to acoustic conditions with varying levels of anthropogenic
noise (e.g., seismic activities, naval sonar, shipping, or fishing
activities);
Inform environmental assessments of current and future
anti-submarine warfare systems; and
Assemble a long-term database of ocean ambient noise data
to enable scientifically-based evaluations of potential influences on
cetaceans or other species.
Acoustic data collected and archived by the M3 program allow
program analysts to statistically quantify how cetacean acoustic
behaviors are affected by various factors, such as ocean basin
topographic features, hydrographic conditions, seasonality, time,
weather conditions, and ambient noise conditions. The compiled acoustic
data can be used to estimate the total number of vocalizing whales per
unit area as well as document the seasonal or localized movements of
individual animals. In addition, observations over time can also show
the interaction and influence of noise sources on large whale behavior.
At present, the M3 Program's data are classified, as are the data
reports created by M3 Program analysts, due to the inclusion of
sensitive national security information. The Navy (OPNAV N974B)
continues to assess and analyze M3 Program data collected from Navy
passive acoustic monitoring systems and is working toward making some
portion of that data (after appropriate security reviews) available to
scientists with appropriate clearances and ultimately to the public.
Additionally, data summaries are shared with NMFS analysts with
appropriate clearances. Progress has been achieved on addressing
securing concerns and declassifying a report of fin whale singing and
swimming behaviors from which a scientific paper has been submitted to
a scientific journal for review (DoN, 2015). In addition, information
on detections of western gray whale vocalizations has been shared with
the IUCN on possible wintering areas for this species.
Additional Ranked Monitoring Projects Under Consideration
Due to research indicating that beaked whales and harbor porpoises
may be particularly sensitive to a range of underwater sound (Southall
et al., 2007; Tyack et al., 2011; Kastelein et al., 2012), in the 2012
rule and LOAs for these activities, NMFS included conditions for
increasing understanding of the potential effects of SURTASS LFA sonar
on these taxa. The Navy convened an independent Scientific Advisory
Group (SAG), composed of six scientists affiliated with two
universities, one Federal agency (NMFS), and three private research and
consultancy firms, to investigate and assess different types of
research and monitoring methods that could increase the understanding
of the potential effects to beaked whales and harbor porpoises from
exposure to SURTASS LFA sonar transmissions. The SAG submitted a report
(``Potential Effects of SURTASS LFA sonar on Beaked Whales and Harbor
Porpoises'') describing their monitoring and research recommendations.
This report was submitted to the Executive Oversight Group (EOG) for
SURTASS LFA sonar, which is comprised of representatives from the U.S.
Navy (Chair, OPNAV N2/N6F24), Office of the Deputy Assistant Secretary
of the Navy for the Environment, Office of Naval Research, Navy Living
Marine Resources Program, and the NMFS Office of Protected Resources
(OPR) Permits and Conservation Division. The EOG met twice in 2014 to
review and further discuss the research recommendations put forth by
the SAG, the feasibility of implementing any of the research efforts,
and existing budgetary constraints. Representatives from the Marine
Mammal Commission also attended EOG meetings as observers. In addition
to the SAG recommendations, promising suggestions for monitoring and
research were recommended for consideration by the EOG. The EOG
considered which efforts would be most effective, given existing
budgetary constraints and the Navy has submitted the outcome of this
study to NMFS.
In summary, after consideration of the SAG recommendations and the
inputs provided by the EOG, the research monitoring studies were ranked
as follows. In addition to the topic, the approximate cost of the
research effort is also listed. Those study topics which the Navy has
invested in since the EOG recommendations are also indicated below.
The category of research recommendations that were ranked
[[Page 7250]]
highest included those estimated to cost less than $100,000.
1. Desktop study of potential overlap of harbor porpoise habitat by
SURTASS LFA sonar transmissions. The Navy funded this study and the
report has been submitted to NMFS. In summary the report finds that,
while harbor porpoises could potentially be exposed to SURTASS LFA
sonar transmissions, exposure is likely to occur at reduced sound
levels with limited potential for behavioral responses. The full report
is available at http://www.surtass-lfa-eis.com.
2. Review existing high frequency acoustic recording package (HARP)
data to determine spatiotemporal overlap with SURTASS LFA missions.
NMFS contacted Erin Oleson (NOAA) about deployments in the western and
central North Pacific and John Hildebrand (Scripps) about deployments
in the eastern North Pacific. Since the EOG, Baumann-Pickering et al.
(2014) presented the results of over eleven cumulative years of HARP
deployments in the North Pacific, which may overlap with SURTASS LFA
missions. It would be fairly straightforward and require minimal cost
to determine the spatiotemporal overlap of HARP deployments and LFA
missions. If it was determined that overlap existed, the cost for data
analysis would depend on the amount of overlap.
The second-highest ranked group of recommendations consisted of
studies that are estimated to cost in the $100,000-$500,000 range, but
for which methodologies exist and implementation would extend existing
studies.
1. Targeted deployment of one HARP sensor in the western North
Pacific for one year; approximate estimated cost of $250,000. The
objective of this study would be to document beaked whale vocal
behavior before, during, and after LFA sonar transmissions. Careful
consideration of lessons learned from previous deployments would be
needed to increase the probability of a successful project.
2. Anatomical modeling of LF sound reception by beaked whales;
approximate estimated cost of $150,000-$200,000. Since the EOG meetings
in 2014, Cranford and Krysl (2015) presented a synthetic audiogram for
a fin whale, predicted based predominantly on bone conduction of sound
through the head to the ear. NMFS (2016) noted that the predicted
audiogram does not match the typical U-shaped audiogram expected with
normal hearing in mammals in that there is a ``hump'' at low
frequencies and shallow roll-off of sensitivity at high frequencies.
Given these difficulties, additional funding would be required to
determine the source of the abnormal results. The Navy is continuing to
invest in LF cetacean audiogram development and recently released a
Broad Agency Announcement in coordination with the Subcommittee on
Ocean Science and Technology--Ocean Noise and Marine Life Task force to
make further investment in this area.
The final group of recommendations are studies that require
additional methodological developments and/or would cost greater than
$500,000.
1. Controlled exposure estimates (CEE) for beaked whales with an
appropriate LF source. There are many complexities associated with this
recommendation, even more so considering the results of the ongoing
mid-frequency sonar behavioral response studies (BRS) demonstrating the
importance of real-world exposures for characterizing behavioral
responses. It is possible that existing LF sources already in use on
Navy ranges could be surrogates for SURTASS LFA sonar, but such
extrapolations would need to be considered carefully. SURTASS LFA sonar
is currently authorized for use in the western and central North
Pacific and Indian oceans, regions in which CEEs have not been
conducted, making experiments with the LFA system itself particularly
difficult. Given the cost and complexities associated with this
recommendation, it was ranked as a lower priority. This recommendation
should also be revisited with future development of tagging
technologies for harbor porpoises.
2. LF behavioral audiograms for harbor porpoise or LF auditory
brainstem response/auditory evoked potential (ABR/AEP) audiograms for
beaked whales. Since the EOG concluded, the Navy funded a study led by
Dr. James Finneran (http://greenfleet.dodlive.mil/files/2017/05/LMRFactSheet_Project9.pdf) to correlate AEP measurements of hearing
sensitivity with perceived loudness (Muslow et al., 2015). Part of this
study included attempts to extend the LF range of AEP measurements,
which may be transferable to studies of hearing sensitivity of harbor
porpoise or beaked whales. There are difficulties with the transmission
of LF sounds, in achieving the required power with manageable
laboratory systems and creating a far-field sound field consistent
across the measurement experiment. The final results of the study have
not been published yet, but the study found that AEPs were only
successful down to frequencies of 10 kHz for bottlenose dolphins (where
10 kHz is the upper range of what is considered mid-frequency) and 1
kHz for California sea lions (the upper range of what is considered
low-frequency). In addition, the correlation of equal latency contours
only applied over a limited frequency range, providing limited benefit
beyond the frequency range of auditory thresholds. Therefore, it is
currently not feasible to conduct ABR/AEPs at frequencies within the
range of SURTASS LFA sonar (100 to 500 Hz). Finally, the Navy funded
audiograms and TTS studies for harbor porpoise across its entire
frequency range (Kastelein et al., 2017). This study reported the
hearing sensitivity of a six-year-old female and a three-year-old male
harbor porpoise as measured by using a standard psycho-acoustic
technique under low ambient noise conditions. The porpoises' hearing
thresholds for 13 narrow-band sweeps with center frequencies between
0.125 and 150 kHz were established. The range of most sensitive hearing
(defined as within 10 dB of maximum sensitivity) was from 16 to 140
kHz. Sensitivity declined sharply above 125 kHz. Hearing sensitivity in
the low frequencies 125 Hz to 1 kHz were 40-80 dB above their maximum
sensitivity.
The Navy has obtained a permit from the NMFS marine mammal health
and stranding program to conduct an AEP audiogram on a stranded beaked
whale, but to date none have stranded alive in an area with staff
suitable to conduct the testing. The Navy will continue to seek
opportunities to conduct such research should they arise.
The ranking of research and monitoring recommendations has helped
inform Navy and NMFS decision makers of the scientific priority,
feasibility, and cost of possible experiments to increase understanding
of potential effects of SURTASS LFA sonar on harbor porpoises and
beaked whales. Discussions among Navy decision makers from OPNAV N2/
N974B/N45, Office of the Deputy Assistant Secretary of the Navy for the
Environment, Office of Naval Research, and Navy Living Marine Resources
Program will continue to leverage research among various programs.
Ongoing discussions between Navy and NMFS will continue to evaluate the
most efficient and cost-effective way forward for Navy research and
environmental compliance monitoring efforts once the amount of funding
authorized is known.
Ambient Noise Data Monitoring
Several efforts (federal and academic) are underway to develop a
comprehensive ocean noise budget (i.e.,
[[Page 7251]]
an accounting of the relative contributions of various underwater
sources to the ocean noise field) for the world's oceans that includes
both anthropogenic and natural sources of noise. Ocean noise
distribution and noise budgets are used in marine mammal masking
studies, habitat characterization, and marine animal impact analyses.
The Navy will collect ambient noise data when the SURTASS passive
towed horizontal line array is deployed. However, because the collected
ambient noise data may also contain sensitive acoustic information, the
Navy classifies the data, and thus does not make these data publicly
available. The Navy is exploring the feasibility of declassifying and
archiving portions of the ambient noise data for incorporation into
appropriate ocean noise budget efforts after all related security
concerns have been resolved.
Research
The Navy sponsors significant research for marine living resources
to study the potential effects of its activities on marine mammals.
OPNAV N974B provides a representative to the Navy's Living Marine
Resources advisory board to provide input to future research projects
that may address SURTASS LFA sonar needs. The most recently available
data are for Fiscal Year 2015, in which the Navy reported that it spent
$35.9 million that year on marine mammal research and conservation
(Marine Mammal Commission, 2017). This ongoing marine mammal research
relates to hearing and hearing sensitivity, auditory effects, marine
mammal monitoring and detection, noise impacts, behavioral responses,
diving physiology and physiological stress, and distribution. The Navy
sponsors a significant portion of U.S. research on the effects of
human-generated underwater sound on marine mammals and approximately 50
percent of such research conducted worldwide. These research projects
may not be specifically related to SURTASS LFA sonar activities;
however, they are crucial to the overall knowledge base on marine
mammals and the potential effects from underwater anthropogenic noise.
The Navy also sponsors research to determine marine mammal abundances
and densities for all Navy ranges and other operational areas. The Navy
notes that research and evaluation is being carried out on various
monitoring and mitigation methods, including passive acoustic
monitoring, and the results from this research could be applicable to
SURTASS LFA sonar passive acoustic monitoring. The Navy has also
sponsored several workshops to evaluate the current state of knowledge
and potential for future acoustic monitoring of marine mammals. The
workshops bring together underwater acoustic subject matter experts and
marine biologists from the Navy and other research organizations to
present data and information on current acoustic monitoring research
efforts, and to evaluate the potential for incorporating similar
technology and methods on Navy instrumented ranges.
Proposed Reporting
In order to issue an ITA 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. There are several different
reporting requirements in these proposed regulations:
Notification of the Discovery of a Stranded Marine Mammal 7
---------------------------------------------------------------------------
\7\ As defined in Title IV of the MMPA, a ``stranding'' is
defined as ``an event in the wild in which (A) a marine mammal is
dead and is (i) on a beach or shore of the United States, or (ii) in
waters under the jurisdiction of the United States (including any
navigable waters); or (B) a marine mammal is alive and is (i) on a
beach or shore of the United States and unable to return to the
water; (ii) on a beach or shore of the United States and, although
able to return to the water, is in need of apparent medical
attention; or (iii) in the waters under the jurisdiction of the
United States (including any navigable waters), but is unable to
return to its natural habitat under its own power or without
assistance.''
---------------------------------------------------------------------------
The Navy will systematically observe SURTASS LFA sonar activities
for injured or disabled marine mammals. In addition, the Navy will
monitor the principal marine mammal stranding networks and other media
to correlate analysis of any whale mass strandings that could
potentially be associated with SURTASS LFA sonar activities.
In the event of a live stranding (or near-shore atypical milling)
event where a stranding network has confirmed the status and location
of the stranding, NMFS (individuals specifically identified in the
Stranding Communication Protocol, NMFS Office of Protected Resources
(OPR)--HQ senior administrators) would advise the Navy of the need to
implement shutdown procedures for any use of SURTASS LFA sonar within
50 km (27 nmi) of the stranding.
Minimization of Harm to Live-Stranded (or Milling) Marine Mammals
In the event of a live stranding (or near-shore atypical milling)
event, NMFS would advise the Navy of the need to implement shutdown
procedures for any use of SURTASS LFA sonar within 50 km (27 nmi) of
the stranding. Following this initial shutdown, NMFS would communicate
with the Navy to determine if circumstances support any modification of
the shutdown zone. The Navy may decline to implement all or part of the
shutdown if the holder of the LOA, or his/her designee, determines that
it is necessary for national security. Shutdown procedures for live
stranding or milling marine mammals include the following:
If at any time, the marine mammal(s) die or are
euthanized, or if herding/intervention efforts that were occurring are
stopped, NMFS (individuals specifically identified in the Stranding
Communication Protocol) would immediately advise the Navy that the
shutdown around that animal(s)' location is no longer needed;
Otherwise, shutdown procedures would remain in effect
until NMFS (individuals specifically identified in the Stranding
Communication Protocol) determines and advises the Navy that all live
animals involved have left the area (either of their own volition or
following an intervention); and
If further observations of the marine mammals indicate the
potential for re-stranding, additional coordination with the Navy may
be required to determine what measures are necessary to minimize that
likelihood (e.g., extending the shutdown or moving operations farther
away) and to implement those measures as appropriate.
Shutdown procedures are not related to the investigation of the
cause of the stranding and their implementation is not intended to
imply that Navy activity is the cause of the stranding. Rather,
shutdown procedures are intended to protect marine mammals exhibiting
indicators of distress by minimizing their exposure to possible
additional stressors, regardless of the factors that contributed to the
stranding.
Navy Discovery of Any Stranded Marine Mammal
In the event that Navy personnel (uniformed military, civilian, or
contractors conducting Navy work) associated with operating a T-AGOS
class vessel discover a live or dead stranded marine mammal at sea, the
Navy shall report the incident to NMFS (see communication protocols
below) as soon as is feasible. The Navy will provide NMFS with:
Time, date, and location (latitude/longitude) of the first
discovery (and
[[Page 7252]]
updated location information if known and applicable);
Species identification (if known) or description of the
marine mammal(s) involved;
Condition of the marine mammal(s) (including carcass
condition if the marine mammal is dead);
Observed behaviors of the marine mammal(s), if alive;
If available, photographs or video footage of the marine
mammal(s); and
General circumstances under which the marine mammal was
discovered (e.g., vessel transit).
Vessel Strike
In the event of a ship strike of a marine mammal by any T-AGOS
class vessel, the Navy shall immediately report, or as soon as security
clearance procedures and safety conditions allow, the information above
in Discovery of Any Stranded Marine Mammal subsection, to NMFS. As soon
as feasible, but no later than seven (7) business days, the Navy shall
additionally report to NMFS, the:
Vessel's speed during and leading up to the incident;
Vessel's course/heading and what training or testing
activity was being conducted (if applicable);
Status of all sound sources in use (e.g., active sonar);
Description of avoidance measures/requirements that were
in place at the time of the strike and what additional measures were
taken, if any, to avoid marine mammal strike;
Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, visibility) immediately preceding the
marine mammal strike;
Estimated size and length of marine mammal that was
struck;
Description of the behavior of the marine mammal
immediately preceding and following the strike;
If available, description of the presence and behavior of
any other marine mammals immediately preceding the strike;
Estimated fate of the marine mammal (e.g., dead, injured
but alive, injured and moving, blood or tissue observed in the water,
status unknown, disappeared, etc.);
To the extent practicable, photographs or video footage of
the struck marine mammal(s); and
Any relevant information discovered during Navy's
investigation of the ship strike.
Annual Report
The classified and unclassified annual reports, which are due no
later than 60 days after the anniversary of the effective date of the
seven-year LOA, would provide NMFS with a summary of the year's
training and testing transmission hours. Specifically, the classified
reports will include dates/times of exercises, location of vessel,
mission operational area, location of the mitigation zone in relation
to the LFA sonar array, marine mammal observations, and records of any
delays or suspensions of activities. Marine mammal observations would
include animal type and/or species, number of animals sighted by
species, date and time of observations, type of detection (visual,
passive acoustic, HF/M3 sonar), the animal's bearing and range from
vessel, behavior, and remarks/narrative (as necessary). The classified
and unclassified reports would include the Navy's analysis of take by
Level B harassment and estimates of the percentage of marine mammal
stocks affected for the year by SURTASS LFA sonar training and testing
activities. The Navy's estimates of the percentage of marine mammal
stocks and number of individual marine mammals affected by exposure to
SURTASS LFA sonar transmissions would be derived using acoustic impact
modeling based on operating locations, season of missions, system
characteristics, oceanographic environmental conditions, and marine
mammal demographics.
Additionally, the annual report would include: (1) Analysis of the
effectiveness of the mitigation measures with recommendations for
improvements where applicable; (2) assessment of any long-term effects
from SURTASS LFA sonar activities; and (3) any discernible or estimated
cumulative impacts from SURTASS LFA sonar training and testing
activities.
Comprehensive Report
NMFS proposes to require the Navy to provide NMFS and the public
with a final comprehensive report analyzing the impacts of SURTASS LFA
sonar training and testing activities on marine mammal species and
stocks. This report would include an in-depth analysis of all
monitoring and Navy-funded research pertinent to SURTASS LFA sonar
activities conducted during the 7-year period of these regulations, a
scientific assessment of cumulative impacts on marine mammal stocks,
and an analysis on the advancement of alternative (passive)
technologies as a replacement for LFA sonar. This report would be a key
document for NMFS' review and assessment of impacts for any future
rulemaking.
The Navy will respond to NMFS comments and requests for additional
information or clarification on the annual or comprehensive reports.
These reports will be considered final after the Navy has adequately
addressed NMFS' comments or provided the requested information, or
three months after the submittal of the draft if NMFS does not comment
within the three-month time period. NMFS will post the annual and
comprehensive reports on the internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
Adaptive Management
Our understanding about marine mammals and the potential effects of
SURTASS LFA sonar on marine mammals is continually evolving. Reflecting
this, the proposed rule again includes an adaptive management
framework. This allows the agencies to consider new/revised peer-
reviewed and published scientific data and/or other information from
qualified and recognized sources within academia, industry, and
government/non-government organizations to determine (with input
regarding practicability) whether SURTASS LFA sonar mitigation,
monitoring, or reporting measures should be modified (including
additions or deletions) and to make such modification if new scientific
data indicate that they would be appropriate. Under this proposed rule,
modifications that are substantial would be made only after a 30-day
period of public review and comment. Substantial modifications include
a change in training and testing areas or new information that results
in significant changes to mitigation.
As discussed in the Mitigation section above, NMFS and Navy have
refined the adaptive management process for this rule compared to
previous rulemakings. In the 2012 rule, NMFS and the Navy annually
considered how new information, from anywhere in the world, should be
considered in an adaptive management context-- including whether this
new information would support the identification of new OBIAs or other
mitigation measures. Moving forward, new information will still be
considered annually, but for the purposes of OBIA identification, only
in the context of the areas covered by the proposed rule. New
information will still be considered annually, but only in the western
and central North Pacific and eastern Indian Oceans in which SURTASS
LFA assets will train and test.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
[[Page 7253]]
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering the numbers of marine mammals that might be taken through
mortality, serious injury, and Level A or Level B harassment (although
only Level B harassment is authorized by this proposed rule), NMFS
considers other factors, such as the likely nature of any responses
(e.g., intensity and duration), the context of any response (e.g.,
critical reproductive time or location, migration, etc.), as well as
effects on habitat, the status of the affected stocks, 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 these analyses 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, ongoing sources of human-caused
mortality, or ambient noise levels).
To avoid repetition, the discussion of our analyses applies to all
the stocks listed in Table 18 (including those for which density and
take estimates have been pooled), because the anticipated effects of
this activity on these different marine mammal stocks are expected to
be similar, given the operational parameters of the activity. While
there are differences in the hearing sensitivity of different groups,
these differences have been factored into the analysis for auditory
impairment. However, the nature of their behavioral responses is
expected to be similar for SURTASS LFA sonar, especially given the
context of their short duration and open ocean exposures. Additionally,
with the operational avoidance of areas that are known to be important
for specific biologically important reasons and coastal standoff zones
and the anticipated low-level effects, there is no need to
differentially evaluate species based on varying status. Where there is
a notable difference in the proportion of authorized takes (as compared
to abundance) for two species, we explicitly address it below.
The Navy has described its specified activities based on best
estimates of the number of hours that the Navy will conduct SURTASS LFA
training and testing activities. The exact number of transmission hours
may vary from year to year, but will not exceed the annual total of 496
transmission hours for all vessels in years 1-4 (currently four
vessels), or the annual total of 592 transmission hours for all vessels
in years 5-7 regardless of the number of vessels in use. (Previous
SURTASS LFA sonar rulemakings evaluated and authorized 432 transmission
hours per vessel per year.)
As mentioned previously, NMFS estimates that 46 species of marine
mammals representing 139 stocks could be taken by Level B harassment
over the course of the seven-year period. For reasons stated
previously, no mortalities or injuries are anticipated to occur as a
result of the Navy's proposed SURTASS LFA sonar training and testing
activities, and none are proposed to be authorized by NMFS. The Navy
has operated SURTASS LFA sonar under NMFS regulations for the last 17
years without any reports of serious injury or death. The evidence to
date, including recent scientific reports, annual monitoring reports,
and 17 years of experience conducting SURTASS LFA activities, further
supports the conclusion that the potential for injury, and particularly
serious injury, to occur is minimal.
Regarding the potential for mortality, as described previously,
neither acoustic impacts resulting in stranding nor ship strikes are
expected to result from SURTASS LFA training and testing. There is no
empirical evidence of strandings or ship strikes of marine mammals
associated spatially or temporally with the employment of SURTASS LFA
sonar. Moreover, the sonar system acoustic characteristics differ
between LFA sonar and MF sonars that have been associated with
strandings: LFA sonars use frequencies from 100 to 500 Hz, with
relatively long signals (pulses) on the order of 60 sec, while MF
sonars use frequencies greater than 1,000 Hz, with relatively short
signals on the order of 1 sec. NMFS also makes a distinction between
the common features shared by the stranding events associated with MF
sonar in Greece (1996), Bahamas (2000), Madeira (2000), Canary Islands
(2002), Hanalei Bay (2004), and Spain (2006), referenced above. These
included operation of MF sonar, deep water close to land (such as
offshore canyons), presence of an acoustic waveguide (surface duct
conditions), and periodic sequences of transient pulses (i.e., rapid
onset and decay times) generated at depths less than 32.8 ft (10 m) by
sound sources moving at speeds of 2.6 m/s (5.1 knots) or more during
sonar operations (D'Spain et al., 2006). None of these features relate
to the proposed SURTASS LFA sonar training and testing activities.
Regarding the potential for ship strike, given the number of vessels,
densities of marine mammals in the area of operation, mitigation, and
ship speed, the potential of strike is so low as to be discountable.
NMFS neither anticipates nor proposes to authorize Level A
harassment of marine mammals as a result of these activities. The
proposed mitigation measures (including visual monitoring along with
active and passive acoustic monitoring, which has been shown to be over
98 percent effective at detecting marine mammals, and implementing a
shutdown zone of 2,000 yds around the LFA sonar array and vessel) would
allow the Navy to avoid exposing marine mammals to received levels of
SURTASS LFA sonar or HF/M3 sonar sound that would result in injury
(Level A harassment) and, as discussed in the Estimated Take of Marine
Mammals section, TTS and more severe behavioral reactions would also be
minimized due to mitigation measures, so that the majority of takes
would be expected to be in the form of less severe Level B harassment.
As noted above, the context of exposures is important in evaluating
the ultimate impacts of Level B harassment on individuals. In the case
of SURTASS LFA sonar, the approaching sound source would be moving
through the open ocean at low speeds, so concerns of noise exposure are
somewhat lessened in this context compared to situations where animals
may not be as able to avoid strong or rapidly approaching sound
sources. In addition, the duration of the take is important; in the
case of SURTASS LFA sonar, the vessel continues to move and any
interruption of behavior would be of relatively short duration.
Further, NMFS and the Navy have imposed geographic restrictions that
minimize behavioral disruption in times and areas where impacts would
be more likely to lead to effects on individual fitness that could
impact the species or stock.
For SURTASS LFA sonar training and testing activities, the Navy
provided information (Table 7-1 of the Navy's application) estimating
incidental take numbers and percentages of marine mammal stocks that
could potentially occur due to SURTASS LFA sonar training and testing
activities based on
[[Page 7254]]
the 15 model areas in the central and western North Pacific and eastern
Indian Oceans. Based on our evaluation, incidental take from the
specified activities associated with the proposed SURTASS LFA sonar
training and testing activities will most likely fall within the realm
of short-term and temporary, or ephemeral, disruption of behavioral
patterns (Level B harassment), will not include Level A harassment, and
is not expected to impact reproduction or survival of individuals. NMFS
bases this assessment on a number of factors (discussed in more detail
in previous sections) considered together:
(1) Geographic Restrictions--The coastal standoff and OBIA
geographic restrictions on SURTASS LFA sonar training and testing
activities are expected to minimize the likelihood of disruption of
marine mammals in areas where important behavior patterns such as
migration, calving, breeding, feeding, or sheltering occur, or in areas
with small resident populations or higher densities of marine mammals.
As a result, the takes that occur are less likely to result in
energetic effects or disturbances of other important behaviors that
would reduce reproductive success or survivorship.
(2) Low Frequency Sonar Scientific Research Program (LFS SRP)--The
Navy designed the three-phase LFS SRP study to assess the potential
impacts of SURTASS LFA sonar on the behavior of low-frequency hearing
specialists, those species believed to be at (potentially) greatest
risk due to the presumed overlap in hearing of these species and the
frequencies at which SURTASS LFA sonar is operated. This field research
addressed three important behavioral contexts for baleen whales: (1)
Blue and fin whales feeding in the southern California Bight, (2) gray
whales migrating past the central California coast, and (3) humpback
whales breeding off Hawaii. These experiments, which exposed baleen
whales to received levels ranging from 120 to about 155 dB re: 1
[mu]Pa, confirmed that some portion of the total number of whales
exposed to LFA sonar responded behaviorally by changing their vocal
activity, moving away from the source vessel, or both, but the
responses were short-lived and animals returned to their normal
activities within tens of minutes after initial exposure. While some of
the observed responses would likely be considered ``take'' under the
MMPA, these short-term Level B harassment responses do not necessarily
constitute significant changes in biologically important behaviors. In
addition, these experiments illustrated that the context of an exposure
scenario is important for determining the probability, magnitude, and
duration of a response. This was shown by the fact that migrating gray
whales responded to a sound source in the middle of their migration
route but showed no response to the same sound source when it was
located offshore, outside the migratory corridor, even when the source
level was increased to maintain the same received levels within the
migratory corridor.
Although the LFS SRP study is nearly two decades old, the collected
behavioral response data remain valid and highly relevant because of
the lack of additional studies utilizing this specific source, but also
because the data show, as reflected in newer studies with other sound
sources, that the context of an exposure (novelty of the sound source,
distance from the sound source and activity of the animals experiencing
exposure, and whether the source is perceived as approaching or moving
away, etc.) is as important, if not sometimes more important than the
source level and frequency in terms of assessing reactions (see the
Behavioral Response/Disturbance section above for discussion of more
recent studies regarding context). Therefore, take estimates for
SURTASS LFA sonar are likely conservative (though we analyze them here
nonetheless), and takes that do occur will primarily be in the form of
lower levels of take by Level B harassment.
(3) Efficacy of the Navy's Three-Part Mitigation Monitoring
Program--Review of Final Comprehensive and Annual Reports, from August
2002 through December 2018, indicates that the HF/M3 active sonar
system has proven to be the most effective of the mitigation monitoring
measures to detect possible marine mammals in proximity to the
transmitting LFA sonar array, and use of this system substantially
increases the probability of detecting marine mammals within the
mitigation zone (and beyond), providing a superior monitoring
capability. Because the HF/M3 active sonar is able to monitor marine
mammals out to an effective range of 2 to 2.5 km (1.2 to 1.5 mi; 1.1 to
1.3 nmi) from the vessel, it is unlikely that the SURTASS LFA
operations would expose marine mammals to an SPL greater than about 174
dB re: 1 [mu]Pa at 1 m. Past results of the HF/M3 sonar system tests
provide confirmation that the system has a demonstrated probability of
single-ping detection of 95 percent or greater for single marine
mammals that are 10 m (32.8 ft) in length or larger, and a probability
approaching 100 percent for multiple pings of any sized marine mammal
(see Chapter 5, section 5.4.3 of the SURTASS 2018 DSEIS/SOEIS for a
summary of the effectiveness of the HF/M3 monitoring system). Lastly,
as noted above, from the commencement of SURTASS LFA sonar use in 2002
through the present, neither operation of LFA sonar, nor operation of
the T-AGOS vessels, has been associated with any mass or individual
strandings of marine mammals. In addition, required monitoring reports
indicate that there have been no apparent avoidance reactions observed,
and no observed exposures to sound levels associated with Level A
harassment takes due to SURTASS LFA sonar since its use began in 2002.
In examining the results of the mitigation monitoring procedures
over the previous 17 years of SURTASS LFA activities, NMFS has
concluded that the mitigation and monitoring measures for triggering
shutdowns of the LFA sonar system have been implemented properly and
have successfully minimized the potential adverse effects of SURTASS
LFA sonar to marine mammals in the 2,000-yard LFA sonar mitigation zone
around the vessel. This conclusion is further supported by
documentation that no known mortality or injury to marine mammals has
occurred over this period.
For reasons discussed in the Potential Effects of the Specified
Activity on Marine Mammals and their Habitat section, NMFS anticipates
that the effect of masking will be limited and the chances of an LFA
sonar sound overlapping whale calls at levels that would interfere with
their detection and recognition will be extremely low. Also as
discussed in that section, NMFS does not expect any short- or long-term
effects to marine mammal food resources from SURTASS LFA sonar training
and testing activities. It is unlikely that the activities of the
SURTASS LFA sonar vessels transmitting LFA sonar at any place in the
action area over the course of a year would implicate all of the areas
for a given species or stock in any year. It is anticipated that ample
similar nearby habitat areas are available for species/stocks in the
event that portions of preferred areas are ensonified. Implementation
of the 2,000-yard LFA shutdown zone would ensure that most marine
mammal takes are limited to lower-level Level B harassment. Further, in
areas of known or likely biological importance for functions such as
feeding, reproduction, etc., effects are mitigated by the coastal
standoff and OBIAs.
[[Page 7255]]
As noted above, because of the nature, scale, and locations of
SURTASS LFA sonar training and testing, there is no reason to expect
meaningfully differential impacts on any particular species or stock
that warrant additional discussion. However, we include the following
to ensure understanding of the two cases where the percentages of
stocks taken are notably higher compared to other stocks. As also noted
previously, the modeling the Navy uses allows for the enumeration of
instances of take--each representing an exposure above the Level B
harassment threshold of a single marine mammal for some amount of time
(likely relatively short) within a single day. The model does not
predict how many of these instances for a given species or stock may
occur as multiple, or repeated, takes to a single individual. Given the
nature (small number of ships and relatively few hours across two ocean
basins) and location (beyond coastal exclusion in open ocean, areas
where species/stocks are not concentrated as much) of the activity, as
well as the relatively small percentages of take compared to abundance
for most stocks (the vast majority below 10 percent, 12 stocks in the
10-20 percent range, and a handful ranging from 20-67 percent) and the
fact that takes of single stocks are expected across multiple regions,
we expect that most individuals taken are taken only once in a year
with some small subset taken perhaps a few times in the course of a
year. However, two stocks have somewhat higher percentages that we note
here. When estimated instances of take are compared to the estimated
stock abundances, the percentages are 117 and 321 for the Western North
Pacific stock of killer whales and the Western North Pacific stock of
humpback whales, respectively. Acknowledging the uncertainty
surrounding abundance estimates for the Navy's action area, it is still
worth noting that these percentages are notably higher than others, and
would suggest that some number of individuals are expected to be taken
more than once. It indicates the possibility that some individuals are
taken several times within a year, as the percentage exceeds 100%. For
example, for the Western North Pacific humpback stock, the average
number of takes would be three or more per individual. It is unlikely
that takes would be exactly evenly distributed across all individuals
and it is therefore more reasonable to assume that some number of
individuals would be taken fewer than three times, while others would
be taken on more than three days, and we assume up to twice that (i.e.,
one individual could be taken on six days) for the sake of analysis.
Even where one individual may be taken (by Level B harassment in the
form of behavioral disturbance or a small degree of TTS) on up to six
days within a year, given the nature of the activities, there is no
reason to expect that these takes would be likely to occur on
sequential days or that this magnitude of exposure within a year would
be likely to result in impacts on reproduction or survival, especially
given the implementation of mitigation to reduce the severity of
impacts.
For the following summarized reasons, pulling in the supporting
information both in this section and previous sections, NMFS has made a
preliminary finding that the total authorized taking from SURTASS LFA
sonar training and testing activities will have a negligible impact on
the affected species or stocks based on following:
(1) The small number of SURTASS LFA sonar systems that would be
operating world-wide (likely not in close proximity to one another) and
the low total number of hours of operation planned across all vessels;
(2) The relatively low duty cycle, short training and testing
events, and offshore nature of the SURTASS LFA sonar;
(3) The fact that marine mammals in unspecified migration corridors
and open ocean concentrations would be adequately protected from
exposure to sound levels that would result in injury, most TTS (and any
accrued would be expected to be of a small degree), and more severe
levels of behavioral disruption by the historical demonstrated
effectiveness of the Navy's three-part monitoring program in detecting
marine mammals and triggering shutdowns;
(4) Geographic restrictions requiring the SURTASS LFA sonar sound
field not exceed 180 dB re 1[micro]Pa within 22 km of any shoreline,
including islands, or at a distance of one km from the perimeter of an
OBIA, thereby limiting the severity and number of behavioral
disturbances; and
(5) The proven effectiveness of the required three-part monitoring
and mitigation protocols.
In summary, 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 proposed
monitoring and mitigation measures, the authorized takes are not
expected to adversely affect any species or stock through impacts on
recruitment or survival. Therefore, NMFS preliminarily finds that the
total authorized marine mammal take from the proposed activity will
have a negligible impact on all affected marine mammal species or
stocks.
Subsistence Harvest of Marine Mammals
The Navy will not operate SURTASS LFA sonar in Arctic waters nor in
the Gulf of Alaska, or off the Aleutian Island chain where subsistence
uses of marine mammals protected under the MMPA occur. Therefore, there
are no relevant subsistence uses of marine mammals implicated by this
action. Therefore, there would be no impact on subsistence hunting, nor
would SURTASS LFA sonar cause abandonment of any harvest/hunting
locations, displace any subsistence users, or place physical barriers
between marine mammals and the hunters. NMFS has preliminarily
determined that the total taking affecting species or stocks would not
have an unmitigable adverse impact on the availability of such species
or stocks for taking for subsistence purposes.
Endangered Species Act
There are 11 marine mammal species under NMFS' jurisdiction that
are listed as endangered or threatened under the ESA with confirmed or
possible occurrence in the central and western North Pacific and
eastern Indian Oceans: The blue; fin; sei; Western North Pacific
distinct population segment (DPS) of humpback; North Pacific right;
Western North Pacific DPS of gray; sperm; and Main Hawaiian Islands
Insular DPS of false killer, as well as the western DPS of the Steller
sea lion; Hawaiian monk seal; and the Southern DPS of spotted seal.
On June 15, 2018, the Navy submitted a Biological Assessment to
NMFS to initiate consultation under section 7 of the ESA for the 2019-
2026 SURTASS LFA sonar training and testing activities. NMFS' proposed
authorization for incidental take under section 101(a)(5)(A) of the
MMPA is also a Federal agency action that requires consultation under
section 7 of the ESA. NMFS and Navy will conclude consultation with
NMFS' Office of Protected Resources, Interagency Cooperation Division
prior to making a determination on the issuance of a final rule and
LOAs.
The USFWS is responsible for regulating the take of the several
marine mammal species including the polar bear, walrus, and dugong. The
Navy has determined that none of these species occur in geographic
areas that overlap with SURTASS LFA sonar activities and, therefore,
that SURTASS LFA
[[Page 7256]]
sonar activities will have no effect on the endangered or threatened
species or the critical habitat of ESA-listed species under the
jurisdiction of the USFWS. Thus, no consultation with the USFWS
pursuant to Section 7 of the ESA will occur.
Classification
This action does not contain any collection of information
requirements for purposes of the Paperwork Reduction Act of 1980 (44
U.S.C. 3501 et seq.).
The Office of Management and Budget has determined that this
proposed rule is not significant for purposes of Executive Order 12866.
Pursuant to the Regulatory Flexibility Act (RFA), the Chief Counsel
for Regulation of the Department of Commerce has certified to the Chief
Counsel for Advocacy of the Small Business Administration that this
proposed rule, if adopted, would not have a significant economic impact
on a substantial number of small entities. The RFA requires a Federal
agency to prepare an analysis of a rule's impact on small entities
whenever the agency is required to publish a notice of proposed
rulemaking. However, a Federal agency may certify, pursuant to 5 U.S.C.
605(b), that the action will not have a significant economic impact on
a substantial number of small entities. The Navy is the sole entity
that will be affected by this rulemaking and is not a small
governmental jurisdiction, small organization, or small business, as
defined by the RFA. Any requirements imposed by LOAs issued pursuant to
these regulations, and any monitoring or reporting requirements imposed
by these regulations, will be applicable only to the Navy.
NMFS does not expect the issuance of these regulations or the
associated LOAs to result in any impacts to small entities pursuant to
the RFA. Because this action, if adopted, would directly affect the
Navy and not a small entity, NMFS concludes the action would not result
in a significant economic impact on a substantial number of small
entities.
List of Subjects in 50 CFR Part 218
Exports, Fish, Imports, Indians, Labeling, Marine mammals,
Penalties, Reporting and recordkeeping requirements, Seafood,
Transportation.
Dated: February 21, 2019.
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 proposed
to be 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.
0
2. Add subpart X to part 218 to read as follows:
Subpart X--Taking and Importing of Marine Mammals; U.S. Navy
Surveillance Towed Array Sensor System Low Frequency Active (SURTASS
LFA) Sonar Training and Testing in the Central and Western North
Pacific and Eastern Indian Oceans
Sec.
218.230 Specified activity, level of taking, and species/stocks.
218.231 Effective dates.
218.232 Permissible methods of taking.
218.233 Prohibitions.
218.234 Mitigation.
218.235 Requirements for monitoring.
218.236 Requirements for reporting.
218.237 Letter of Authorization.
218.238 Renewals and modifications of a Letter of Authorization.
Subpart X--Taking and Importing of Marine Mammals; U.S. Navy
Surveillance Towed Array Sensor System Low Frequency Active
(SURTASS LFA) Sonar Training and Testing in the Central and Western
North Pacific and Eastern Indian Oceans
Sec. 218.230 Specified activity, level of taking, and species/stocks.
Regulations in this subpart apply to the U.S. Navy (Navy) for the
taking of marine mammals that occurs incidental to the Navy's SURTASS
LFA sonar training and testing activities under authority of the
Secretary of the Navy within the central and western North Pacific and
eastern Indian Oceans (SURTASS LFA Sonar Study Area) (Table 1 to Sec.
218.230).
Table 1 to Sec. 218.230--Species/Stocks Proposed for Authorization by
Level B Harassment for the 7-Year Period of the Proposed Rule by SURTASS
LFA Sonar Training and Testing Activities
------------------------------------------------------------------------
Species Stock \1\
------------------------------------------------------------------------
Antarctic minke whale............. ANT.
Blue whale........................ CNP, NIND, WNP, SIND.
Bryde's whale..................... ECS, Hawaii, WNP, NIND, SIND.
Common minke whale................ Hawaii, IND, WNP JW, WNP OE, YS.
Fin whale......................... ECS, Hawaii, IND, SIND, WNP.
Humpback whale.................... CNP stock and Hawaii DPS, WAU stock
and DPS, WNP stock and DPS.
North Pacific right whale......... WNP.
Omura's whale..................... NIND, SIND, WNP.
Sei whale......................... Hawaii, SIND, NP, NIND.
Western North Pacific gray whale.. WNP stock and Western DPS.
Baird's beaked whale.............. WNP.
Blainville's beaked whale......... Hawaii, WNP, IND.
Common bottlenose dolphin......... 4-Islands, Hawaii Island, Hawaii
Pelagic, IA, IND, Japanese Coastal,
Kauai/Niihau, Oahu, WNP Northern
Offshore, WNP Southern Offshore,
WAU.
Common dolphin.................... IND, WNP.
Cuvier's beaked whale............. Hawaii, IND, SH, WNP.
Dall's porpoise................... SOJ dalli type, WNP dalli ecotype,
WNP truei ecotype.
Deraniyagala's beaked whale....... IND, NP.
Dwarf sperm whale................. Hawaii, IND, WNP.
False killer whale................ Hawaii Pelagic, IA, IND, Main
Hawaiian Islands Insular stock and
DPS, Northwestern Hawaiian Islands,
WNP.
Fraser's dolphin.................. CNP, Hawaii, IND, WNP.
Ginkgo-toothed beaked whale....... IND, NP.
Harbor porpoise................... WNP.
Hubbs' beaked whale............... NP.
Indo-Pacific bottlenose dolphin... IND.
[[Page 7257]]
Killer whale...................... Hawaii, IND, WNP.
Kogia spp......................... WNP.
Longman's beaked whale............ Hawaii, IND, WNP.
Melon-headed whale................ Hawaiian Islands, IND, Kohala
Resident, WNP.
Mesoplodon spp.................... WNP.
Northern right whale dolphin...... NP.
Pacific white-sided dolphin....... NP.
Pantropical spotted dolphin....... 4-Islands, Hawaii Island, Hawaiian
Pelagic, IND, Oahu, WNP.
Pygmy killer whale................ Hawaii, IND, WNP.
Pygmy sperm whale................. Hawaii, IND, WNP.
Risso's dolphin................... Hawaii, IA, WNP, IND.
Rough-toothed dolphin............. Hawaii, IND, WNP.
Short-finned pilot whale.......... Hawaii, IND, WNP Northern Ecotype,
WNP Southern Ecotype.
Southern bottlenose whale......... IND.
Spade-toothed beaked whale........ IND.
Sperm whale....................... Hawaii, NIND, NP, SIND.
Spinner dolphin................... Hawaii Island, Hawaii Pelagic, IND,
Kauai/Niihau, Kure/Midway Atoll,
Oahu/4-Islands, Pearl and Hermes
Reef, WNP.
Stejneger's beaked whale.......... WNP.
Striped dolphin................... Hawaii, IND, Japanese Coastal, WNP
Northern Offshore, WNP Southern
Offshore.
Hawaiian monk seal................ Hawaii.
Northern fur seal................. Western Pacific.
Ribbon seal....................... NP.
Spotted seal...................... Alaska stock/Bering Sea DPS,
Southern stock and DPS.
Steller sea lion.................. Western/Asian stock, Western DPS.
------------------------------------------------------------------------
\1\ ANT=Antarctic; CNP=Central North Pacific; NP=North Pacific;
NIND=Northern Indian; SIND=Southern Indian; IND=Indian; WNP=Western
North Pacific; ECS=East China Sea; WP=Western Pacific; SOJ=Sea of
Japan; IA=Inshore Archipelago; WAU=Western Australia; YS=Yellow Sea;
OE=Offshore Japan; OW=Nearshore Japan; JW=Sea of Japan/Minke;
JE=Pacific coast of Japan; SH=Southern Hemisphere; DPS=distinct
population segment.
Sec. 218.231 Effective dates.
Regulations in this subpart are effective from August 13, 2019,
through August 12, 2026.
Sec. 218.232 Permissible methods of taking.
Under a Letter or Letters of Authorization (LOA) issued pursuant to
Sec. 216.106 of this chapter and Sec. 218.237, the Holder of the LOA
(hereinafter ``Navy'') may incidentally, but not intentionally, take
marine mammals within the area described in Sec. 218.230 by Level B
harassment associated with SURTASS LFA sonar training and testing
provided the activity is in compliance with all terms, conditions, and
requirements of the regulations in this subpart and the applicable LOA.
Sec. 218.233 Prohibitions.
Notwithstanding takings contemplated in Sec. 218.230 and
authorized by a LOA issued under Sec. Sec. 216.106 of this chapter and
218.237, no person in connection with the activities described in Sec.
218.230 may:
(a) Violate, or fail to comply with, the terms, conditions, and
requirements of this subpart or a LOA issued under Sec. Sec. 216.106
of this chapter and 218.237;
(b) Take any marine mammal not specified in such LOAs;
(c) Take any marine mammal specified in such LOAs in any manner
other than Level B harassment;
(d) Take any marine mammal specified in the LOA if NMFS makes a
determination that such taking is having, or may have, more than a
negligible impact on the species or stocks concerned; or
(e) Take a marine mammal specified in the LOA if NMFS determines
such taking is having, or may have, an unmitigable adverse impact on
availability of the species or stock for taking for subsistence uses.
Sec. 218.234 Mitigation.
When conducting activities identified in Sec. 218.230, the
mitigation measures described in this section and in any LOA issued
under Sec. Sec. 216.106 of this chapter and 218.237 must be
implemented.
(a) Personnel training--Lookouts: The Navy will utilize one or more
trained marine biologists qualified in conducting at-sea marine mammal
visual monitoring to conduct at-sea marine mammal visual monitoring
training and qualify designated ship personnel to conduct at-sea visual
monitoring. Training will ensure quick and effective communication
within the command structure in order to facilitate implementation of
protective measures if they detect marine mammals and may be
accomplished either in-person, or via video training.
(b) General operating procedures. (1) Prior to SURTASS LFA sonar
activities, the Navy will promulgate executive guidance for the
administration, execution, and compliance with the environmental
regulations under these regulations and LOA.
(2) The Navy must not transmit the SURTASS LFA sonar signal at a
frequency greater than 500 Hz.
(c) 2,000-yard LFA sonar mitigation/buffer zone; Suspension and
Delay. If a marine mammal is detected, through monitoring required
under Sec. 218.235, within or about to enter within 2,000 yards of the
SURTASS LFA source (i.e., the LFA mitigation/buffer zone), the Navy
must immediately delay or suspend SURTASS LFA sonar transmissions.
(d) Resumption of SURTASS LFA sonar transmissions. (1) The Holder
of a LOA may not resume SURTASS LFA sonar transmissions earlier than 15
minutes after:
(i) All marine mammals have left the area of the 2,000-yard LFA
sonar mitigation zone; and
(ii) There is no further detection of any marine mammal within the
2,000-yard LFA sonar mitigation zone as determined by the visual,
passive, and high frequency monitoring described in Sec. 218.235.
(2) [Reserved]
[[Page 7258]]
(e) Ramp-up procedures for the high-frequency marine mammal
monitoring (HF/M3) sonar required under Sec. 218.235. (1) The Navy
must ramp up the HF/M3 sonar power level beginning at a maximum source
sound pressure level of 180 dB: re 1 [mu]Pa at 1 meter in 10-dB
increments to operating levels over a period of no less than five
minutes:
(i) At least 30 minutes prior to any SURTASS LFA sonar
transmissions; and
(ii) Anytime after the HF/M3 source has been powered down for more
than two minutes.
(2) The Navy must not increase the HF/M3 sound pressure level once
a marine mammal is detected; ramp-up may resume once marine mammals are
no longer detected.
(f) Geographic restrictions on the SURTASS LFA sonar sound field.
(1) LFA sonar training and testing activities must be conducted such
that:
(i) The received level of SURTASS LFA sonar transmissions will not
exceed 180 dB within 22 km (12 nmi) from any emergent land, including
offshore islands;
(ii) The received level of SURTASS LFA sonar transmissions will not
exceed 180 dB re: 1 [mu]Pa (rms) at a distance less than 1 km (0.5 nmi)
seaward of the outer perimeter of any Offshore Biologically Important
Area (OBIA) designated in Sec. 218.234(f)(2), or subsequently
identified through the Adaptive Management process specified in Sec.
218.241, during the period specified. The boundaries and periods of
such OBIAs will be kept on file in NMFS' Office of Protected Resources
and on its website at https://www.fisheries.noaa.gov/national/marine-
mammal-protection/incidental-take-authorizations-military-readiness-
activities.
(iii) No activities with the SURTASS LFA system will occur within
territorial seas of foreign nations, which are areas from 0 up to 12
nmi from shore, depending on the distance that individual nations
claim; and
(iv) No activities with the SURTASS LFA system will occur within
Hawaii state waters (out to 3 nmi) or in the waters of Penguin Bank and
ensonification of Hawaii state waters will not be at levels above 145
dB.
(2) Offshore Biologically Important Areas (OBIAs) for marine
mammals (with specified periods) for SURTASS LFA sonar training and
testing activities include the following (Table 1 to paragraph (f)(2):
Table 1 to Paragraph (f)(2)--Offshore Biologically Important Areas
(OBIA)
[Note: This table will be updated to include a finalized list of OBIAs
for the Final Rule after continued coordination with Navy and review of
information received from the Proposed Rule to finalize consideration of
the candidate OBIAs.]
------------------------------------------------------------------------
Name of area Location of area Months of importance
------------------------------------------------------------------------
Penguin Bank, Hawaiian North-Central November through
Islands Humpback Whale NMS. Pacific Ocean. April, annually.
Northern Bay of Bengal and Bay of Bengal/ Year-round.
Head of Swatch-of-No-Ground Northern Indian
(SoNG). Ocean.
Offshore Sri Lanka.......... North-Central Indian December through
Ocean. April, annually.
Camden Sound/Kimberly Region Southeast Indian June through
Ocean; northwestern September,
Australia. annually.
------------------------------------------------------------------------
(g) Minimization of additional harm to live-stranded (or milling)
mammals. The Navy must consult the Notification and Reporting Plan,
which sets out the requirements for when live stranded marine mammals
are reported in the Study Area. The Stranding and Notification Plan is
available at: https://www.fisheries.noaa.gov/action/incidental-take-
authorization-us-navy-operations-surveillance-towed-array-sensor-
system-0.
Sec. 218.235 Requirements for monitoring.
(a) The Navy must:
(1) Conduct visual monitoring from the ship's bridge during all
daylight hours (30 minutes before sunrise until 30 minutes after
sunset). During training and testing activities that employ SURTASS LFA
sonar in the active mode, the SURTASS vessels must have lookouts to
maintain a topside watch with standard binoculars (7x) and with the
naked eye.
(2) Use the passive SURTASS sonar component to detect vocalizing
marine mammals; and
(3) Use the HF/M3 sonar to locate and track marine mammals in
relation to the SURTASS LFA sonar vessel and the sound field produced
by the SURTASS LFA sonar source array, subject to the ramp-up
requirements in Sec. 216.234(e) of this chapter.
(b) Monitoring under paragraph (a) of this section must:
(1) Commence at least 30 minutes before the first SURTASS LFA sonar
training and testing transmission;
(2) Continue between transmission pings; and
(3) Continue either for at least 15 minutes after completion of the
SURTASS LFA sonar training and testing transmission, or, if marine
mammals are exhibiting unusual changes in behavioral patterns, for a
period of time until behavior patterns return to normal or conditions
prevent continued observations.
(c) The Navy must designate qualified on-site individuals to
conduct the mitigation, monitoring and reporting activities specified
in these regulations and LOA issued under Sec. Sec. 216.106 of this
chapter and 218.237.
(d) The Navy must continue to assess data from the Marine Mammal
Monitoring Program and work toward making some portion of that data,
after appropriate security reviews, available to scientists with
appropriate clearances. Any portions of the analyses conducted by these
scientists based on these data that are determined to be unclassified
after appropriate security reviews will be made publically available.
(e) The Navy must collect ambient noise data and will explore the
feasibility of declassifying and archiving the ambient noise data for
incorporation into appropriate ocean noise budget efforts.
(f) The Navy must conduct all monitoring required under LOAs.
Sec. 218.236 Requirements for reporting.
(a) The Navy must submit classified and unclassified annual mission
reports to the Director, Office of Protected Resources, NMFS, no later
than 60 days after the end of each year covered by the LOA beginning on
the date of effectiveness of a LOA. Each annual mission report will
include a summary of all active-mode missions completed during that
year. At a minimum, each classified mission report must contain the
following information:
(1) Dates, times, and location of each vessel during each mission;
(2) Information on sonar transmissions during each mission;
[[Page 7259]]
(3) Results of the marine mammal monitoring program specified in
the LOA; and
(4) Estimates of the percentages of marine mammal species and
stocks affected (both for the year and cumulatively for each successive
year) covered by the LOA.
(b) The seventh annual report must be prepared as a final
comprehensive report, which will include information for the final year
as well as the prior six years of activities under the rule. This final
comprehensive report must also contain an unclassified analysis of new
passive sonar technologies and an assessment of whether such a system
is feasible as an alternative to SURTASS LFA sonar, and be submitted to
the Director, Office of Protected Resources, NMFS as described in this
paragraph (b).
(c) The Navy will continue to assess the data collected by its
undersea arrays and work toward making some portion of that data, after
appropriate security reviews, available to scientists with appropriate
clearances. Any portions of the analyses conducted by these scientists
based on these data that are determined to be unclassified after
appropriate security reviews will be made publically available.
(d) The Navy must consult the Notification and Reporting Plan,
which sets out notification, reporting, and other requirements for when
dead, injured, or live stranded marine mammals are reported in the
Study Area. The Stranding and Notification Plan is available at:
https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-
navy-operations-surveillance-towed-array-sensor-system-0.
Sec. 218.237 Letter of Authorization.
(a) To incidentally take marine mammals pursuant to these
regulations, Navy must apply for and obtain a Letter of Authorization
(LOA).
(b) An LOA, unless suspended or revoked, may be effective for a
period of time not to exceed the expiration date of these regulations.
(c) If an LOA expires prior to the expiration date of these
regulations, Navy may apply for and obtain a renewal of the LOA.
(d) In the event of projected changes to the activity or to
mitigation and monitoring measures required by an LOA (excluding
changes made pursuant to the adaptive management provision of Sec.
218.239), the Navy must apply for and obtain a modification of the LOA
as described in Sec. 218.238.
(e) The LOA shall set forth:
(1) Permissible methods of incidental taking;
(2) Means of effecting the least practicable adverse impact on the
species, its habitat, and on the availability of the species for
subsistence uses (i.e., mitigation); and
(3) Requirements for monitoring and reporting.
(f) Issuance of the LOA will be based on a determination that the
level of taking will be consistent with the findings made for the total
taking allowable under these regulations.
(g) Notice of issuance or denial of an LOA will be published in the
Federal Register within thirty days of a determination.
Sec. 218.238 Renewals and modifications of a Letter of Authorization.
(a) An LOA issued under Sec. [thinsp]216.106 of this chapter and
Sec. 218.237 for the activity identified in Sec. [thinsp]218.230 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 the regulations in this subpart
(excluding changes made pursuant to the adaptive management provision
in paragraph (c)(1) of this section); and
(2) NMFS determines that the mitigation, monitoring, and reporting
measures required by the previous LOA(s) 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 the regulations 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 planned 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. [thinsp]216.106 of this chapter and
Sec. 218.237 may be modified by NMFS under the following
circumstances:
(1) Adaptive management. 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 the regulations in
this subpart or subsequent LOAs.
(ii) If, through adaptive management, the modifications to the
mitigation, monitoring, or reporting measures are substantial, NMFS
will publish a notice of planned LOA in the Federal Register and
solicit public comment.
(2) Emergencies. 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.
[thinsp]216.106 of this chapter and Sec. 218.237, an LOA may be
modified without prior notice or opportunity for public comment. Notice
would be published in the Federal Register within thirty days of the
action.
[FR Doc. 2019-03298 Filed 2-28-19; 8:45 am]
BILLING CODE 3510-22-P