[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





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National Oceanic and Atmospheric Administration





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50 CFR Part 218





Takes of Marine Mammals Incidental to Specified Activities: Taking 
Marine Mammals Incidental to 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  

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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.

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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

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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

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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

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[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