[Federal Register Volume 83, Number 247 (Thursday, December 27, 2018)]
[Rules and Regulations]
[Pages 66846-67031]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-27342]



[[Page 66845]]

Vol. 83

Thursday,

No. 247

December 27, 2018

Part II





Department of Commerce





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National Oceanic and Atmospheric Administration





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50 CFR Part 218





Taking and Importing Marine Mammals; Taking Marine Mammals Incidental 
to the U.S. Navy Training and Testing Activities in the Hawaii-Southern 
California Training and Testing Study Area; Final Rule

Federal Register / Vol. 83 , No. 247 / Thursday, December 27, 2018 / 
Rules and Regulations

[[Page 66846]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 218

[Docket No. 170918908-8999-02]
RIN 0648-BH29


Taking and Importing Marine Mammals; Taking Marine Mammals 
Incidental to the U.S. Navy Training and Testing Activities in the 
Hawaii-Southern California Training and Testing Study Area

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

ACTION: Final rule; notification of issuance of Letters of 
Authorization.

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SUMMARY: NMFS, upon request from the U.S. Navy (Navy) issues these 
regulations pursuant to the Marine Mammal Protection Act (MMPA) to 
govern the taking of marine mammals incidental to the training and 
testing activities conducted in the Hawaii-Southern California Training 
and Testing (HSTT) Study Area over the course of five years beginning 
in December 2018. These regulations, which allow for the issuance of 
Letters of Authorization (LOA) for the incidental take of marine 
mammals during the described activities and timeframes, prescribe the 
permissible methods of taking and other means of effecting the least 
practicable adverse impact on marine mammal species or stocks and their 
habitat, and establish requirements pertaining to the monitoring and 
reporting of such taking.

DATES: Effective from December 21, 2018 through December 20, 2023.

ADDRESSES: A copy of the Navy's application and supporting documents, 
as well as a list of the references cited in this document, may be 
obtained online at: www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities. In case of problems accessing these documents, please call 
the contact listed below (see FOR FURTHER INFORMATION CONTACT).

FOR FURTHER INFORMATION CONTACT: Stephanie Egger, Office of Protected 
Resources, National Marine Fisheries Service, 1315 East-West Highway, 
Silver Spring, MD 20910, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Purpose of Regulatory Action

    These regulations, issued under the authority of the MMPA (16 
U.S.C. 1361 et seq.), establish a framework for authorizing the take of 
marine mammals incidental to the Navy's training and testing activities 
(categorized as military readiness activities) from the use of sonar 
and other transducers, in-water detonations, air guns, impact pile 
driving/vibratory extraction, and potential vessel strikes based on 
Navy movement throughout the HSTT Study Area. The HSTT Study Area (see 
Figure 1.1-1 of the Navy's rulemaking/LOA application) is comprised of 
established operating and warning areas across the north-central 
Pacific Ocean, from the mean high tide line in Southern California west 
to Hawaii and the International Date Line. The Study Area includes the 
at-sea areas of three existing range complexes (the Hawaii Range 
Complex, the Southern California (SOCAL) Range Complex, and the Silver 
Strand Training Complex), and overlaps a portion of the Point Mugu Sea 
Range (PMSR). Also included in the Study Area are Navy pierside 
locations in Hawaii and Southern California, Pearl Harbor, San Diego 
Bay, and the transit corridor \1\ on the high seas where sonar training 
and testing may occur.
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    \1\ Vessel transit corridors are the routes typically used by 
Navy assets to traverse from one area to another. The route depicted 
in Figure 1-1 of the Navy's rulemaking/LOA application is the 
shortest route between Hawaii and Southern California, making it the 
quickest and most fuel efficient. The depicted vessel transit 
corridor is notional and may not represent the actual routes used by 
ships and submarines transiting from Southern California to Hawaii 
and back. Actual routes navigated are based on a number of factors 
including, but not limited to, weather, training, and operational 
requirements.
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    We received an application from the Navy requesting five-year 
regulations and authorizations to incidentally take individuals of 
multiple species and stocks of marine mammals (``Navy's rulemaking/LOA 
application'' or ``Navy's application''). Take is anticipated to occur 
by Level A and Level B harassment as well as a very small number of 
serious injuries or mortalities incidental to the Navy's training and 
testing activities.
    Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs 
the Secretary of Commerce (as delegated to NMFS) to allow, upon 
request, the incidental, but not intentional taking of small numbers of 
marine mammals by U.S. citizens who engage in a specified activity 
(other than commercial fishing) within a specified geographical region 
if, after notice and public comment, the agency makes certain findings 
and issues regulations that set forth permissible methods of taking 
pursuant to that activity, as well as monitoring and reporting 
requirements. Section 101(a)(5)(A) of the MMPA and the implementing 
regulations at 50 CFR part 216, subpart I, provide the legal basis for 
issuing this final rule and the subsequent LOAs. As directed by this 
legal authority, this final rule contains mitigation, monitoring, and 
reporting requirements.

Summary of Major Provisions Within the Final Rule

    Following is a summary of the major provisions of this final rule 
regarding the Navy's activities. Major provisions include, but are not 
limited to:

    [ssquf] The use of defined powerdown and shutdown zones (based 
on activity);
    [ssquf] Measures to reduce or eliminate the likelihood of ship 
strikes;
    [ssquf] Activity limitations in certain areas and times that are 
biologically important (i.e., for foraging, migration, reproduction) 
for marine mammals;
    [ssquf] Implementation of a Notification and Reporting Plan (for 
dead, live stranded, or marine mammals struck by a vessel); and
    [ssquf] Implementation of a robust monitoring plan to improve 
our understanding of the environmental effects resulting from the 
Navy training and testing activities.

    Additionally, the rule includes an adaptive management component 
that allows for timely modification of mitigation or monitoring 
measures based on new information, when appropriate.

Background

    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, a notice of a proposed 
authorization is provided to the public for review and the opportunity 
to submit comments.
    An authorization for incidental takings shall be granted if NMFS 
finds that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking, other means of 
effecting the least practicable adverse impact on the species or stocks 
and their habitat, and requirements pertaining to monitoring and 
reporting of such takings are set forth. The MMPA states that the term 
``take'' means to harass, hunt, capture, kill or attempt to harass, 
hunt, capture, or kill any marine mammal.

[[Page 66847]]

    The National Defense Authorization Act of 2004 (2004 NDAA) (Pub. L. 
108-136) amended section 101(a)(5) of the MMPA to remove the ``small 
numbers'' and ``specified geographical region'' provisions indicated 
above for ``military readiness activities'' and amended the definition 
of ``harassment'' as it applies to military readiness activities, along 
with certain research activities. The definitions of all applicable 
MMPA statutory terms cited above are included in the relevant sections 
below.
    More recently, the John S. McCain National Defense Authorization 
Act for Fiscal Year 2019 (2019 NDAA) (Pub. L. 115-232) amended the MMPA 
to allow incidental take rules for military readiness activities to be 
issued for up to seven years. That recent amendment of the MMPA does 
not affect this final rule, however, because both the Navy's 
application and NMFS' proposed incidental take rule preceded passage of 
the 2019 NDAA and contemplated authorization for five years.

Summary and Background of Request

    On September 13, 2017, NMFS received an application from the Navy 
for authorization to take marine mammals by Level A and B harassment 
incidental to training and testing activities (categorized as military 
readiness activities) from the use of sonar and other transducers, in-
water detonations, air guns, and impact pile driving/vibratory 
extraction in the HSTT Study Area. In addition, the Navy requested 
incidental take authorization by serious injury or mortality for a 
combined ten takes of two marine mammal species from explosives and for 
up to three takes of large whales from vessel strikes over the five-
year period. On October 13, 2017, the Navy sent an amendment to its 
application and the application was found to be adequate and complete. 
On October 20, 2017 (82 FR 48801), we published a notice of receipt of 
application (NOR) in the Federal Register, requesting comments and 
information related to the Navy's request for 30 days. On June 26, 
2018, we published a notice of the proposed rulemaking (83 FR 29872) 
and requested comments and information related to the Navy's request 
for 45 days. Comments received during the NOR and the proposed 
rulemaking comment periods are addressed in this final rule. See 
further details addressing comments received in the Comments and 
Responses section.
    On September 10, 2018, and October 26, 2018, Navy provided NMFS 
with memoranda revising the estimated takes by serious injury or 
mortality included in the Navy's rulemaking/LOA application for ship 
strike. The Navy's request for takes by serious injury or mortality of 
three large whales over the course of five years remains unchanged. 
However, specifically, after further analysis and discussion with NMFS, 
the Navy modified their request for takes from particular stocks in the 
following ways:

    <bullet> Humpback whales (California, Oregon, Washington (CA/OR/
WA) stock):
    [cir] Reduced request for take from two to one individual.
    [cir] Removed the authorization request for individuals that 
also are part of the Central America Distinct Population Segment 
(DPS) recognized under the Endangered Species Act (ESA). Both the 
Central America DPS and Mexico DPS overlap with the CA/OR/WA stock, 
but from this stock, only a humpback whale from the Mexico DPS is 
expected to be taken by serious injury or mortality. These 
individuals, that are part of both the CA/OR/WA stock and the Mexico 
DPS, will be referred to as ``humpback whales (CA/OR/WA stock, 
Mexico DPS)'' henceforth.
    <bullet> Sperm whale (Hawaii or CA/OR/WA stock):
    [cir] Original authorization request for take was for two total 
from any stock; reduced request for take to one individual.
    [cir] Removed request for individuals from the CA/OR/WA stock, 
i.e., only an individual from the Hawaii stock is requested.
    <bullet> Bryde's whale (Eastern Tropical Pacific stock or Hawaii 
stock)--Reduced request for take from one individual to zero.
    <bullet> Minke whale (Hawaii stock)--Reduced request for take 
from one individual to zero.
    <bullet> Sei whale (Hawaii stock and Eastern North Pacific 
stock)--Reduced request for take from one individual to zero.

    NMFS concurs that it is reasonably likely that these lethal takes 
could occur. The information and assessment that supports this change 
is included in the Estimated Take of Marine Mammals section.
    The Navy requested two five-year LOAs, one for training activities 
and one for testing activities to be conducted within the HSTT Study 
Area. The HSTT Study Area (see Figure 1.1-1 of the Navy's rulemaking/
LOA application) is comprised of established operating and warning 
areas across the north-central Pacific Ocean, from the mean high tide 
line in Southern California west to Hawaii and the International Date 
Line. The Study Area includes the at-sea areas of three existing range 
complexes (the Hawaii Range Complex, the SOCAL Range Complex, and the 
Silver Strand Training Complex), and overlaps a portion of the PMSR. 
Also included in the Study Area are Navy pierside locations in Hawaii 
and Southern California, Pearl Harbor, San Diego Bay, and the transit 
corridor on the high seas where sonar training and testing may occur.
    The following types of training and testing, which are classified 
as military readiness activities pursuant to the MMPA, as amended by 
the 2004 NDAA, would be covered under the regulations and associated 
LOAs: Amphibious warfare (in-water detonations), anti-submarine warfare 
(sonar and other transducers, in-water detonations), surface warfare 
(in-water detonations), mine warfare (sonar and other transducers, in-
water detonations), and other warfare activities (sonar and other 
transducers, pile driving, air guns). Also, ship strike by Navy vessels 
is addressed and covered, as appropriate.
    This will be NMFS' third in a series of rulemakings for testing and 
training activities in the HSTT Study Area. Hawaii and Southern 
California were separate in the initial rulemaking period, and the 
first two rules were effective from January 5, 2009, through January 5, 
2014 (74 FR 1456; January 12, 2009), and January 14, 2009, through 
January 14, 2014 (74 FR 3882; January 21, 2009), respectively. The 
rulemaking for the second five-year period, which combined Hawaii and 
Southern California, was in effect from December 24, 2013, through 
December 24, 2018 (78 FR 78106; December 24, 2013), as modified by the 
terms of a stipulated settlement agreement and order issued by the 
United States District Court for the District of Hawaii on September 
14, 2015. The new regulations described here will be valid for five 
years, from December 21, 2018, though December 20, 2023.
    The Navy's mission is to organize, train, equip, and maintain 
combat-ready naval forces capable of winning wars, deterring 
aggression, and maintaining freedom of the seas. This mission is 
mandated by Federal law (10 U.S.C. 5062), which ensures the readiness 
of the naval forces of the United States. The Navy executes this 
responsibility by training and testing at sea, often in designated 
operating areas (OPAREA) and testing and training ranges. The Navy must 
be able to access and utilize these areas and associated sea space and 
air space in order to develop and maintain skills for conducting naval 
activities.
    The Navy plans to conduct training and testing activities within 
the HSTT Study Area. The Navy has been conducting similar military 
readiness activities in the HSTT Study Area since the 1940s. The tempo 
and types of training and testing activities have fluctuated because of 
the introduction of new technologies, the evolving nature of 
international events, advances in warfighting doctrine and procedures, 
and changes in force structure

[[Page 66848]]

(organization of ships, weapons, and personnel). Such developments 
influenced the frequency, duration, intensity, and location of required 
training and testing activities, but the basic nature of sonar and 
explosive events conducted in the HSTT Study Area has remained the 
same.
    The Navy's rulemaking/LOA application reflects the most up to date 
compilation of training and testing activities deemed necessary to 
accomplish military readiness requirements. The types and numbers of 
activities included in the rule account for fluctuations in training 
and testing in order to meet evolving or emergent military readiness 
requirements.
    These regulations cover training and testing activities that would 
occur for a five-year period following the expiration of the current 
MMPA authorization for the HSTT Study Area, which expires on December 
24, 2018.

Description of the Specified Activity

    Additional detail regarding the specified activity was provided in 
our Federal Register notice of proposed rulemaking (83 FR 29872; June 
26, 2018); please see that notice of proposed rulemaking or the Navy's 
application for more information. Since the proposed rule, NMFS and the 
Navy have reached agreement on additional mitigation measures which are 
summarized below and discussed in greater detail in the Mitigation 
Measures section of this rule.
    The Navy will implement pre- and post-event observation of the 
mitigation zone for all in-water explosive event mitigation measures in 
the HSTT Study Area. The Navy expanded their mitigation areas to 
include the sections of the Santa Monica Bay to Long Beach and San 
Nicolas Island biologically important areas (BIAs) that overlap the 
HSTT Study Area. These areas are referred to as the Santa Monica/Long 
Beach and San Nicolas Island Mitigation Areas and explosive use is 
limited in these areas as described in the Mitigation Measures section. 
Further, the Navy will limit surface ship sonar such that it will not 
exceed 200 hours from June through October cumulatively within the San 
Diego Arc, San Nicolas Island, and Santa Monica/Long Beach, Mitigation 
Areas. The Navy will also add a year-round limitation on explosives to 
the 4-Islands Region Mitigation Area, which includes a portion of the 
false killer whale (Main Hawaiian Island insular stock) BIA north of 
Maui and Molokai in the HSTT Study Area. The Navy has agreed to issue 
notification messages to increase operator awareness of the presence of 
marine mammals. The Navy will review WhaleWatch, a program coordinated 
by NMFS' West Coast Region as an additional information source to 
inform the drafting of the seasonal awareness message to alert vessels 
in the area to the possible presence of concentrations of large whales, 
including blue, gray, and fin whales in SOCAL.
    In coordination with NMFS, the Navy has also revised its estimate 
of and request for serious injury or mortality takes of large whales 
from ship strikes, as described immediately above in the Summary and 
Background of Request section. The detailed rationale for this change 
is provided in the Estimated Take of Marine Mammals section.

Overview of Training and Testing Activities

    The Navy routinely trains and tests in the HSTT Study Area in 
preparation for national defense missions. Training and testing 
activities covered in these regulations are summarized below.
Primary Mission Areas
    The Navy categorizes its activities into functional warfare areas 
called primary mission areas. These activities generally fall into the 
following seven primary mission areas: Air warfare; amphibious warfare; 
anti-submarine warfare (ASW); electronic warfare; expeditionary 
warfare; mine warfare (MIW); and surface warfare (SUW). Most activities 
addressed in the HSTT FEIS/OEIS are categorized under one of the 
primary mission areas; the testing community has three additional 
categories of activities for vessel evaluation, unmanned systems, and 
acoustic and oceanographic science and technology. Activities that do 
not fall within one of these areas are listed as ``other activities.'' 
Each warfare community (surface, subsurface, aviation, and special 
warfare) may train in some or all of these primary mission areas. The 
testing community also categorizes most, but not all, of its testing 
activities under these primary mission areas.
    The Navy describes and analyzes the impacts of its training and 
testing activities within the HSTT FEIS/OEIS and the Navy's rulemaking/
LOA application (documents available at www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities). In its assessment, the Navy concluded 
that sonar and other transducers, in-water detonations, air guns, and 
pile driving/removal were the stressors that would result in impacts on 
marine mammals that could rise to the level of harassment (and serious 
injury or mortality by explosives or by vessel strike) as defined under 
the MMPA. Therefore, the rulemaking/LOA application provides the Navy's 
assessment of potential effects from these stressors in terms of the 
various warfare mission areas in which they would be conducted. In 
terms of Navy's primary warfare areas, this includes:

    [ssquf] Amphibious warfare (in-water detonations);
    [ssquf] ASW (sonar and other transducers, in-water detonations);
    [ssquf] SUW (in-water detonations);
    [ssquf] MIW (sonar and other transducers, in-water detonations); 
and
    [ssquf] Other warfare activities (sonar and other transducers, 
impact pile driving/vibratory removal, air guns).
Overview of Major Training Exercises and Other Exercises Within the 
HSTT Study Area
    A major training exercise (MTE) is comprised of several ``unit 
level'' range exercises conducted by several units operating together 
while commanded and controlled by a single Commander. These exercises 
typically employ an exercise scenario developed to train and evaluate 
the strike group in naval tactical tasks. In an MTE, most of the 
activities being directed and coordinated by the Commander are 
identical in nature to the activities conducted during individual, 
crew, and smaller unit level training events. In an MTE, however, these 
disparate training tasks are conducted in concert, rather than in 
isolation.
    Some integrated or coordinated ASW exercises are similar in that 
they are comprised of several unit level exercises but are generally on 
a smaller scale than an MTE, are shorter in duration, use fewer assets, 
and use fewer hours of hull-mounted sonar per exercise. For the purpose 
of analysis, three key factors are used to identify and group major, 
integrated, and coordinated exercises including the scale of the 
exercise, duration of the exercise, and amount of hull-mounted sonar 
hours modeled/used for the exercise. NMFS considered the effects of all 
training exercises, not just these major, integrated, and coordinated 
training exercises in these regulations. Additional detail regarding 
the training activities was provided in our Federal Register notice of 
proposed rulemaking (83 FR 29872; June 26, 2018); please see that 
notice of proposed rulemaking or the Navy's application for more 
information.
Overview of Testing Activities Within the HSTT Study Area
    The Navy's research and acquisition community engages in a broad 
spectrum

[[Page 66849]]

of testing activities in support of the fleet. These activities 
include, but are not limited to, basic and applied scientific research 
and technology development; testing, evaluation, and maintenance of 
systems (e.g., missiles, radar, and sonar) and platforms (e.g., surface 
ships, submarines, and aircraft); and acquisition of systems and 
platforms to support Navy missions and give a technological edge over 
adversaries. The individual commands within the research and 
acquisition community included in the Navy's rulemaking/LOA application 
are the Naval Air Systems Command, the Naval Sea Systems Command, the 
Office of Naval Research, and the Space and Naval Warfare Systems 
Command. Additional detail regarding the testing activities was 
provided in our Federal Register notice of proposed rulemaking (83 FR 
29872; June 26, 2018); please see that notice of proposed rulemaking or 
the Navy's application for more information.

Dates and Duration

    The specified activities may occur at any time during the five-year 
period of validity of the regulations. Planned number and duration of 
training and testing activities are shown in the Planned Activities 
section (Tables 4 through 7).

Specific Geographic Area

    The Navy's HSTT Study Area extends from the north-central Pacific 
Ocean, from the mean high tide line in Southern California west to 
Hawaii and the International Date Line, including the Hawaii and 
Southern California (SOCAL) Range Complexes, as well as the Silver 
Strand Training Complex and overlapping a small portion of the Point 
Mugu Sea Range (PMSR). Please refer to Figure 1-1 of the Navy's 
rulemaking/LOA application for a map of the HSTT Study Area, Figures 2-
1 to 2-4 for the Hawaii Operating Area (where the majority of training 
and testing activities occur within the Hawaii Range Complex), Figures 
2-5 to 2-7 for the SOCAL Range Complex, and Figure 2-8 for the Silver 
Strand Training Complex.

Description of Acoustic and Explosive Stressors

    The Navy uses a variety of sensors, platforms, weapons, and other 
devices, including ones used to ensure the safety of Sailors and 
Marines, to meet its mission. Training and testing with these systems 
may introduce acoustic (sound) energy or shock waves from explosives 
into the environment. The Navy's rulemaking/LOA application describes 
specific components that could act as stressors by having direct or 
indirect impacts on the environment. The following subsections describe 
the acoustic and explosive stressors for biological resources within 
the HSTT Study Area. Because of the complexity of analyzing sound 
propagation in the ocean environment, the Navy relies on acoustic 
models in its environmental analyses that consider sound source 
characteristics and varying ocean conditions across the HSTT Study 
Area. Stressor/resource interactions that were determined to have de 
minimus or no impacts (i.e., vessel, aircraft, or weapons noise) were 
not carried forward for analysis in the Navy's rulemaking/LOA 
application. NMFS reviewed the Navy's analysis and conclusions and 
finds them complete and supportable.

Acoustic Stressors

    Acoustic stressors include acoustic signals emitted into the water 
for a specific purpose, such as sonar, other transducers (devices that 
convert energy from one form to another--in this case, to sound waves), 
and air guns, as well as incidental sources of broadband sound produced 
as a byproduct of impact pile driving and vibratory extraction. 
Explosives also produce broadband sound but are analyzed separately 
from other acoustic sources due to their unique characteristics. In 
order to better organize and facilitate the analysis of approximately 
300 sources of underwater sound used for training and testing by the 
Navy, including sonars, other transducers, air guns, and explosives, a 
series of source classifications, or source bins, were developed. The 
source classification bins do not include the broadband sounds produced 
incidental to pile driving, vessel or aircraft transits, weapons 
firing, and bow shocks.
    The use of source classification bins provides the following 
benefits: Provides the ability for new sensors or munitions to be 
covered under existing authorizations, as long as those sources fall 
within the parameters of a ``bin;'' improves efficiency of source 
utilization data collection and reporting requirements under the MMPA 
authorizations; ensures a conservative approach to all impact 
estimates, as all sources within a given class are modeled as the most 
impactful source (highest source level, longest duty cycle, or largest 
net explosive weight) within that bin; allows analyses to be conducted 
in a more efficient manner, without any compromise of analytical 
results; and provides a framework to support the reallocation of source 
usage (hours/explosives) between different source bins, as long as the 
total numbers of takes remain within the overall analyzed and 
authorized limits. This flexibility is required to support evolving 
Navy training and testing requirements, which are linked to real world 
events.
Sonar and Other Transducers
    Active sonar and other transducers emit non-impulsive sound waves 
into the water to detect objects, safely navigate, and communicate. 
Passive sonars differ from active sound sources in that they do not 
emit acoustic signals; rather, they only receive acoustic information 
about the environment, or listen.
    The Navy employs a variety of sonars and other transducers to 
obtain and transmit information about the undersea environment. Some 
examples are mid-frequency hull-mounted sonar used to find and track 
submarines; high-frequency small object detection sonars used to detect 
mines; high frequency underwater modems used to transfer data over 
short ranges; and extremely high-frequency (>200 kilohertz (kHz)). 
Doppler sonars used for navigation, like those used on commercial and 
private vessels. The characteristics of these sonars and other 
transducers, such as source level, beam width, directivity, and 
frequency, depend on the purpose of the source. Higher frequencies can 
carry more information or provide more information about objects off 
which they reflect, but attenuate more rapidly. Lower frequencies 
attenuate less rapidly, so may detect objects over a longer distance, 
but with less detail.
    Additional detail regarding sound sources and platforms and 
categories of acoustic stressors was provided in our Federal Register 
notice of proposed rulemaking (83 FR 29872; June 26, 2018); please see 
that notice of proposed rulemaking or the Navy's application for more 
information.
    Sonars and other transducers are grouped into classes that share an 
attribute, such as frequency range or purpose of use. Classes are 
further sorted by bins based on the frequency or bandwidth; source 
level; and, when warranted, the application in which the source would 
be used, as follows:

    [ssquf] Frequency of the non-impulsive acoustic source;
    [cir] Low-frequency sources operate below 1 kHz;
    [cir] Mid-frequency sources operate at and above 1 kHz, up to 
and including 10 kHz;
    [cir] High-frequency sources operate above 10 kHz, up to and 
including 100 kHz;
    [cir] Very high-frequency sources operate above 100 kHz but 
below 200 kHz;
    [ssquf] Sound pressure level (SPL) of the non-impulsive source;

[[Page 66850]]

    [cir] Greater than 160 decibels (dB) re 1 micro Pascal ([mu]Pa), 
but less than 180 dB re 1 [mu]Pa;
    [cir] Equal to 180 dB re 1 [mu]Pa and up to 200 dB re 1 [mu]Pa;
    [cir] Greater than 200 dB re 1 [mu]Pa;
    [ssquf] Application in which the source would be used;
    [cir] Sources with similar functions that have similar 
characteristics, such as pulse length (duration of each pulse), beam 
pattern, and duty cycle.

    The bins used for classifying active sonars and transducers that 
are quantitatively analyzed in the HSTT Study Area are shown in Table 1 
below. While general parameters or source characteristics are shown in 
the table, actual source parameters are classified.

Table 1--Sonar and Transducers Quantitatively Analyzed in the HSTT Study
                                  Area
------------------------------------------------------------------------
     Source class category             Bin              Description
------------------------------------------------------------------------
Low-Frequency (LF): Sources      LF3              LF sources greater
 that produce signals less than  LF4               than 200 dB.
 1 kHz.                                           LF sources equal to
                                                   180 dB and up to 200
                                                   dB.
                                 LF5              LF sources less than
                                                   180 dB.
                                 LF6              LF sources greater
                                                   than 200 dB with long
                                                   pulse lengths.
Mid-Frequency (MF): Tactical     MF1              Hull-mounted surface
 and non-tactical sources that                     ship sonars (e.g., AN/
 produce signals between 1-10                      SQS-53C and AN/SQS-
 kHz.                                              60).
                                 MF1K             Kingfisher mode
                                                   associated with MF1
                                                   sonars.
                                 MF2              Hull-mounted surface
                                                   ship sonars (e.g., AN/
                                                   SQS-56).
                                 MF3              Hull-mounted submarine
                                                   sonars (e.g., AN/BQQ-
                                                   10).
                                 MF4              Helicopter-deployed
                                                   dipping sonars (e.g.,
                                                   AN/AQS-13).
                                 MF5              Active acoustic
                                                   sonobuoys (e.g.,
                                                   DICASS).
                                 MF6              Active underwater
                                                   sound signal devices
                                                   (e.g., MK84).
                                 MF8              Active sources
                                                   (greater than 200 dB)
                                                   not otherwise binned.
                                 MF9              Active sources (equal
                                                   to 180 dB and up to
                                                   200 dB) not otherwise
                                                   binned.
                                 MF10             Active sources
                                                   (greater than 160 dB,
                                                   but less than 180 dB)
                                                   not otherwise binned.
                                 MF11             Hull-mounted surface
                                                   ship sonars with an
                                                   active duty cycle
                                                   greater than 80%.
                                 MF12             Towed array surface
                                                   ship sonars with an
                                                   active duty cycle
                                                   greater than 80%.
                                 MF13             MF sonar sources.
High-Frequency (HF): Tactical    HF1              Hull-mounted submarine
 and non-tactical sources that   HF2               sonars (e.g., AN/BQQ-
 produce signals between 10-100                    10).
 kHz.                                             HF Marine Mammal
                                                   Monitoring System.
                                 HF3              Other hull-mounted
                                                   submarine sonars
                                                   (classified).
                                 HF4              Mine detection,
                                                   classification, and
                                                   neutralization sonar
                                                   (e.g., AQS-20).
                                 HF5              Active sources
                                                   (greater than 200 dB)
                                                   not otherwise binned.
                                 HF6              Active sources (equal
                                                   to 180 dB and up to
                                                   200 dB) not otherwise
                                                   binned.
                                 HF7              Active sources
                                                   (greater than 160 dB,
                                                   but less than 180 dB)
                                                   not otherwise binned.
                                 HF8              Hull-mounted surface
                                                   ship sonars (e.g., AN/
                                                   SQS-61).
Anti-Submarine Warfare (ASW):    ASW1             MF systems operating
 Tactical sources (e.g., active  ASW2              above 200 dB.
 sonobuoys and acoustic counter- ASW3             MF Multistatic Active
 measures systems) used during                     Coherent sonobuoy
 ASW training and testing                          (e.g., AN/SSQ-125).
 activities.                                      MF towed active
                                                   acoustic
                                                   countermeasure
                                                   systems (e.g., AN/SLQ-
                                                   25).
                                 ASW4             MF expendable active
                                                   acoustic device
                                                   countermeasures
                                                   (e.g., MK 3).
                                 ASW5             MF sonobuoys with high
                                                   duty cycles.
Torpedoes (TORP): Source         TORP1            Lightweight torpedo
 classes associated with the                       (e.g., MK 46, MK 54,
 active acoustic signals                           or Anti-Torpedo
 produced by torpedoes.                            Torpedo).
                                 TORP2            Heavyweight torpedo
                                                   (e.g., MK 48).
                                 TORP3            Heavyweight torpedo
                                                   (e.g., MK 48).
Forward Looking Sonar (FLS):     FLS2             HF sources with short
 Forward or upward looking                         pulse lengths, narrow
 object avoidance sonars used                      beam widths, and
 for ship navigation and safety.                   focused beam
                                                   patterns.
                                 FLS3             VHF sources with short
                                                   pulse lengths, narrow
                                                   beam widths, and
                                                   focused beam
                                                   patterns.
Acoustic Modems (M): Systems     M3               MF acoustic modems
 used to transmit data through                     (greater than 190
 the water.                                        dB).
Swimmer Detection Sonars (SD):   SD1-SD2          HF and VHF sources
 Systems used to detect divers                     with short pulse
 and submerged swimmers.                           lengths, used for the
                                                   detection of swimmers
                                                   and other objects for
                                                   the purpose of port
                                                   security.
Synthetic Aperture Sonars        SAS1             MF SAS systems.
 (SAS): Sonars in which active   SAS2             HF SAS systems.
 acoustic signals are post-      SAS3             VHF SAS systems.
 processed to form high-
 resolution images of the
 seafloor.
                                 SAS4             MF to HF broadband
                                                   mine countermeasure
                                                   sonar.
Broadband Sound Sources (BB):    BB4              LF to MF oceanographic
 Sonar systems with large        BB7               source.
 frequency spectra, used for                      LF oceanographic
 various purposes.                                 source.
                                 BB9              MF optoacoustic
                                                   source.
------------------------------------------------------------------------
Notes: ASW: Antisubmarine Warfare; BB: Broadband Sound Sources; FLS:
  Forward Looking Sonar; HF: High-Frequency; LF: Low-Frequency; M:
  Acoustic Modems; MF: Mid-Frequency; SAS: Synthetic Aperture Sonars;
  SD: Swimmer Detection Sonars; TORP: Torpedoes; VHF: Very High-
  Frequency.


[[Page 66851]]

Air Guns
    Small air guns with capacities up to 60 cubic inches (in\3\) would 
be used during testing activities in various offshore areas of the 
Southern California Range Complex and in the Hawaii Range Complex. 
Generated impulses would have short durations, typically a few hundred 
milliseconds, with dominant frequencies below 1 kHz. The root mean 
square (SPL rms) and peak pressure (SPL peak) at a distance 1 meter (m) 
from the air gun would be approximately 215 dB re 1 [mu]Pa and 227 dB 
re 1 [mu]Pa, respectively, if operated at the full capacity of 60 
in\3\.
Pile Driving/Extraction
    Impact pile driving and vibratory pile removal would occur during 
construction of an Elevated Causeway System (ELCAS), a temporary pier 
that allows the offloading of ships in areas without a permanent port. 
The source levels of the noise produced by impact pile driving and 
vibratory pile removal from an actual ELCAS impact pile driving and 
vibratory removal are shown in Table 2.

                                            Table 2--Elevated Causeway System Pile Driving and Removal Underwater Sound Levels in the HSTT Study Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
            Pile size and type                        Method                                                          Average sound levels at 10 m
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
24-in. Steel Pipe Pile...................  Impact \1\.................  192 dB re 1 [micro]Pa SPL rms, 182 dB re 1 [micro]Pa\2\s SEL (single strike).
24-in. Steel Pipe Pile...................  Vibratory \2\..............  146 dB re 1 [micro]Pa SPL rms, 145 dB re 1 [micro]Pa\2\s SEL (per second of duration).
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Illingworth and Rodkin (2016), \2\ Illingworth and Rodkin (2015).
Notes: in = inch, SEL = Sound Exposure Level, SPL = Sound Pressure Level, rms = root mean squared, dB re 1 [micro]Pa = decibels referenced to 1 micropascal.

    The size of the pier and number of piles used in an ELCAS event is 
approximately 1,520 ft long, requiring 119 supporting piles. 
Construction of the ELCAS would involve intermittent impact pile 
driving over approximately 20 days. Crews work 24 hours (hrs) a day and 
would drive approximately 6 piles in that period. Each pile takes about 
15 minutes to drive with time taken between piles to reposition the 
driver. When training events that use the ELCAS are complete, the 
structure would be removed using vibratory methods over approximately 
10 days. Crews would remove about 12 piles per 24-hour period, each 
taking about 6 minutes to remove.

Explosive Stressors

    This section describes the characteristics of explosions during 
naval training and testing. The activities analyzed in the Navy's 
rulemaking/LOA application that use explosives are described in 
Appendix A (Navy Activity Descriptions) of the HSTT FEIS/OEIS. 
Additional detail regarding explosive stressors was provided in our 
Federal Register notice of proposed rulemaking (83 FR 29872; June 26, 
2018); please see that notice of proposed rulemaking or the Navy's 
application for more information.
    Explosive detonations during training and testing activities are 
associated with high-explosive munitions, including, but not limited 
to, bombs, missiles, rockets, naval gun shells, torpedoes, mines, 
demolition charges, and explosive sonobuoys. Explosive detonations 
during training and testing involving the use of high-explosive 
munitions (including bombs, missiles, and naval gun shells) could occur 
in the air or at the water's surface. Explosive detonations associated 
with torpedoes and explosive sonobuoys would occur in the water column; 
mines and demolition charges would be detonated in the water column or 
on the ocean bottom. Most detonations would occur in waters greater 
than 200 ft in depth, and greater than 3 nautical miles (Nmi) from 
shore, although most mine warfare, demolition, and some testing 
detonations would occur in shallow water close to shore. Those that 
occur close to shore are typically conducted on designated ranges.
    In order to better organize and facilitate the analysis of 
explosives used by the Navy during training and testing that could 
detonate in water or at the water surface, explosive classification 
bins were developed. Explosives detonated in water are binned by net 
explosive weight. The bins of explosives that are for use in the HSTT 
Study Area are shown in Table 3 below.

           Table 3--Explosives Analyzed in the HSTT Study Area
------------------------------------------------------------------------
                                     Net explosive     Example explosive
               Bin                 weight \1\  (lb)         source
------------------------------------------------------------------------
E1..............................  0.1-0.25..........  Medium-caliber
                                                       projectile.
E2..............................  >0.25-0.5.........  Medium-caliber
                                                       projectile.
E3..............................  >0.5-2.5..........  Large-caliber
                                                       projectile.
E4..............................  >2.5-5............  Mine
                                                       neutralization
                                                       charge.
E5..............................  >5-10.............  5-inch projectile.
E6..............................  >10-20............  Hellfire missile.
E7..............................  >20-60............  Demo block/shaped
                                                       charge.
E8..............................  >60-100...........  Light-weight
                                                       torpedo.
E9..............................  >100-250..........  500 lb. bomb.
E10.............................  >250-500..........  Harpoon missile.
E11.............................  >500-650..........  650 lb. mine.
E12.............................  >650-1,000........  2,000 lb. bomb.
E13 \2\.........................  >1,000-1,740......  Multiple Mat Weave
                                                       charges.
------------------------------------------------------------------------
\1\ Net Explosive Weight refers to the equivalent amount of TNT.
\2\ E13 is not modeled for protected species impacts in water because
  most energy is lost into the air or to the bottom substrate due to
  detonation in very shallow water. In addition, activities are confined
  to small coves without regular marine mammal occurrence. These are not
  single charges, but multiple smaller charges detonated simultaneously
  or within a short time period.


[[Page 66852]]

Explosive Fragments
    Marine mammals could be exposed to fragments from underwater 
explosions associated with the specified activities. When explosive 
ordnance (e.g., bomb or missile) detonates, fragments of the weapon are 
thrown at high-velocity from the detonation point, which can injure or 
kill marine mammals if they are struck. These fragments may be of 
variable size and are ejected at supersonic speed from the detonation. 
The casing fragments will be ejected at velocities much greater than 
debris from any target due to the proximity of the casing to the 
explosive material. Risk of fragment injury reduces exponentially with 
distance as the fragment density is reduced. Fragments underwater tend 
to be larger than fragments produced by in-air explosions (Swisdak and 
Montaro, 1992). Underwater, the friction of the water would quickly 
slow these fragments to a point where they no longer pose a threat. In 
contrast, the blast wave from an explosive detonation moves efficiently 
through the seawater. Because the ranges to mortality and injury due to 
exposure to the blast wave far exceed the zone where fragments could 
injure or kill an animal, the thresholds are assumed to encompass risk 
due to fragmentation.

Other Stressor--Vessel Strike

    Vessel strikes are not specific to any particular training or 
testing activity, but rather a potential, limited, sporadic, and 
incidental result of Navy vessel movement within the HSTT Study Area. 
Navy vessels transit at speeds that are optimal for fuel conservation 
or to meet training and testing requirements. Should a vessel strike 
occur, it would likely result in incidental take from serious injury 
and/or mortality and, accordingly, for the purposes of the analysis we 
assume that any authorized ship strike would result in serious injury 
or mortality. Information on Navy vessel movements is provided in the 
Planned Activities section. Additional detail on vessel strike was 
provided in our Federal Register notice of proposed rulemaking (83 FR 
29872; June 26, 2018); please see that notice of proposed rulemaking or 
the Navy's application for more information. Additionally, as 
referenced above and described in more detail in the Estimated Take of 
Marine Mammals section, on September 10, 2018, and October 26, 2018, 
the Navy provided additional information withdrawing and reducing 
certain species from their request for serious injury or mortality 
takes from vessel strike with explanation supporting the Navy's change 
in requested take.

Planned Activities

Planned Training Activities

    The training activities that the Navy plans to conduct in the HSTT 
Study Area are summarized in Table 4. The table is organized according 
to primary mission areas and includes the activity name, associated 
stressors applicable to these regulations, description of the activity, 
sound source bin, the number of planned activities, and the locations 
of those activities in the HSTT Study Area. For further information 
regarding the primary platform used (e.g., ship or aircraft type) see 
Appendix A (Navy Activity Descriptions) of the HSTT FEIS/OEIS.
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Planned Testing Activities

    Testing activities covered in these regulations are described in 
Table 5 through Table 8.
Naval Air Systems Command
    Table 5 summarizes the planned testing activities for the Naval Air 
Systems Command analyzed within the HSTT Study Area.

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[[Page 66861]]


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Naval Sea Systems Command
    Table 6 summarizes the planned testing activities for the Naval Sea 
Systems Command analyzed within the HSTT Study Area.

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Office of Naval Research
    Table 7 summarizes the planned testing activities for the Office of 
Naval Research analyzed within the HSTT Study Area.
[GRAPHIC] [TIFF OMITTED] TR27DE18.013

Space and Naval Warfare Systems Command
    Table 8 summarizes the planned testing activities for the Space and 
Naval Warfare Systems Command analyzed within the HSTT Study Area.

[[Page 66866]]

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Summary of Acoustic and Explosive Sources Analyzed for Training and 
Testing

    Table 9 through Table 12 show the acoustic source classes and 
numbers, explosive source bins and numbers, air gun sources, and pile 
driving and removal activities associated with Navy training and 
testing activities in the HSTT Study Area that were analyzed in this 
rule. Table 9 shows the acoustic source classes (i.e., LF, MF, and HF) 
that could occur in any year under the Planned Activities for training 
and testing activities. Under the Planned Activities, acoustic source 
class use would vary annually, consistent with the number of annual 
activities summarized above. The five-year total for the Planned 
Activities takes into account that annual variability.

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[[Page 66870]]


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    Table 10 shows the number of air gun shots planned in the HSTT 
Study Area for training and testing activities.

          Table 10--Training and Testing Air Gun Sources Quantitatively Analyzed in the HSTT Study Area
----------------------------------------------------------------------------------------------------------------
                                                                   Training                     Testing
    Source class category          Bin        Unit \1\   -------------------------------------------------------
                                                             Annual     5-Year total     Annual     5-Year total
----------------------------------------------------------------------------------------------------------------
Air Guns (AG): Small                   AG              C            0             0           844         4,220
 underwater air guns........
----------------------------------------------------------------------------------------------------------------
\1\ C = count. One count (C) of AG is equivalent to 100 air gun firings.

    Table 11 summarizes the impact pile driving and vibratory pile 
removal activities that would occur during a 24-hour period. Annually, 
for impact pile driving, the Navy will drive 119 piles, two times a 
year for a total of 238 piles. Over the five-year period of the rule, 
the Navy will drive a total of 1,190 piles by impact pile driving. 
Annually, for vibratory pile extraction, the Navy will extract 119 
piles, two times a year for a total of 238 piles. Over the five-year 
period of the rule, the Navy will extract a total of 1,190 piles by 
vibratory pile extraction.

       Table 11--Summary of Pile Driving and Removal Activities per 24-Hour Period in the HSTT Study Area
----------------------------------------------------------------------------------------------------------------
                                                                                                       Total
                                                                                                  estimated time
                             Method                                Piles per 24-   Time per pile   of noise per
                                                                    hour period       minutes     24-hour period
                                                                                                      minutes
----------------------------------------------------------------------------------------------------------------
Pile Driving (Impact)...........................................               6              15              90
Pile Removal (Vibratory)........................................              12               6              72
----------------------------------------------------------------------------------------------------------------


[[Page 66871]]

    Table 12 shows the number of in-water explosives that could be used 
in any year under the Planned Activities for training and testing 
activities. Under the Planned Activities, bin use would vary annually, 
consistent with the number of annual activities summarized above. The 
five-year total for the Planned Activities takes into account that 
annual variability.
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Vessel Movement

    Vessels used as part of the Planned Activities include ships, 
submarines, unmanned vessels, and boats ranging in size from small, 22 
ft (7 m) rigid hull inflatable boats to aircraft carriers with lengths 
up to 1,092 ft (333 m). The average speed of large Navy ships ranges 
between 10 and 15 knots and submarines generally operate at speeds in 
the range of 8-13 knots, while a few specialized vessels can travel at 
faster speeds. Small craft (for purposes of this analysis, less than 18 
m in length) have much more variable speeds (0-50+ knots (kn), 
dependent on the activity), but generally range from 10 to 14 kn. From 
unpublished Navy data, average median speed for large Navy ships in the 
HSTT Study Area from 2011-2015 varied from 5-10 kn with variations by 
ship class and location (i.e., slower

[[Page 66872]]

speeds close to the coast). While these speeds for large and small 
craft are representative of most events, some vessels need to 
temporarily operate outside of these parameters.
    The number of Navy vessels used in the HSTT Study Area varies based 
on military training and testing requirements, deployment schedules, 
annual budgets, and other dynamic factors. Most training and testing 
activities involve the use of vessels. These activities could be widely 
dispersed throughout the HSTT Study Area, but would be typically 
conducted near naval ports, piers, and range areas. Navy vessel traffic 
would especially be concentrated near San Diego, California and Pearl 
Harbor, Hawaii. There is no seasonal differentiation in Navy vessel use 
because of continual operational requirements from Combatant 
Commanders. The majority of large vessel traffic occurs between the 
installations and the OPAREAs. Support craft would be more concentrated 
in the coastal waters in the areas of naval installations, ports, and 
ranges. Activities involving vessel movements occur intermittently and 
are variable in duration, ranging from a few hours up to weeks.

Standard Operating Procedures

    For training and testing to be effective, personnel must be able to 
safely use their sensors and weapon systems as they are intended to be 
used in a real-world situation and to their optimum capabilities. While 
standard operating procedures are designed for the safety of personnel 
and equipment and to ensure the success of training and testing 
activities, their implementation often yields additional benefits to 
environmental, socioeconomic, public health and safety, and cultural 
resources.
    Because standard operating procedures are essential to safety and 
mission success, the Navy considers them to be part of the planned 
activities, and has included them in the environmental analysis. 
Additional details on standard operating procedures were provided in 
our Federal Register notice of proposed rulemaking (83 FR 29872; June 
26, 2018); please see that notice of proposed rulemaking or the Navy's 
application for more information.

Duration and Location

    Training and testing activities would be conducted under this 
authorization in the HSTT Study Area throughout the years. The HSTT 
Study Area (see Figure 1.1-1 of the Navy's rulemaking/LOA application) 
is comprised of established operating and warning areas across the 
north-central Pacific Ocean, from the mean high tide line in Southern 
California west to Hawaii and the International Date Line. The Study 
Area includes the at-sea areas of three existing range complexes (the 
Hawaii Range Complex, the SOCAL Range Complex, and the Silver Strand 
Training Complex), and overlaps a portion of the PMSR. Also included in 
the Study Area are Navy pierside locations in Hawaii and Southern 
California, Pearl Harbor, San Diego Bay, and the transit corridor \2\ 
on the high seas where sonar training and testing may occur.
---------------------------------------------------------------------------

    \2\ Vessel transit corridors are the routes typically used by 
Navy assets to traverse from one area to another. The route depicted 
in Figure 1-1 of the Navy's rulemaking/LOA application is the 
shortest route between Hawaii and Southern California, making it the 
quickest and most fuel efficient. The depicted vessel transit 
corridor is notional and may not represent the actual routes used by 
ships and submarines transiting from Southern California to Hawaii 
and back. Actual routes navigated are based on a number of factors 
including, but not limited to, weather, training, and operational 
requirements.
---------------------------------------------------------------------------

    A Navy range complex consists of geographic areas that encompass a 
water component (above and below the surface) and airspace, and may 
encompass a land component where training and testing of military 
platforms, tactics, munitions, explosives, and electronic warfare 
systems occur. Range complexes include OPAREAs and special use 
airspace, which may be further divided to provide better control of the 
area and events being conducted for safety reasons. Please refer to the 
regional maps provided in the Navy's rulemaking/LOA application 
(Figures 2-1 through 2-8) for additional detail of the range complexes 
and testing ranges. Additional detail on range complexes and testing 
ranges was provided in our Federal Register notice of proposed 
rulemaking (83 FR 29872; June 26, 2018); please see that notice of 
proposed rulemaking or the Navy's application for more information.

Comments and Responses

    We published a notice of proposed regulations in the Federal 
Register on June 26, 2018 (83 FR 29872), with a 45-day comment period. 
In that notice of proposed rulemaking, we requested public input on the 
requests for authorization described therein, our analyses, and the 
proposed authorizations, and requested that interested persons submit 
relevant information, suggestions, and comments. During the 45-day 
comment period, we received 22 comment letters in total. Of this total, 
two submissions were from other Federal agencies, two letters were from 
organizations or individuals acting in an official capacity (e.g., non-
governmental organizations (NGOs)) and 18 submissions were from private 
citizens. NMFS has reviewed all public comments received on the 
proposed rule and issuance of the LOAs. All relevant comments and our 
responses are described below. We provide no response to specific 
comments that addressed species or statutes not relevant to our 
proposed actions under section 101(a)(5)(A) of the MMPA (e.g., comments 
related to sea turtles). We organize our comment responses by major 
categories.

General Comments

    The majority of the 18 comment letters from private citizens 
expressed general opposition toward the Navy's proposed training and 
testing activities and requested that NMFS not issue the LOAs, but 
without providing information relevant to NMFS' decisions. These 
comments appear to indicate a lack of understanding of the MMPA's 
requirement that NMFS ``shall issue'' requested authorizations when 
certain findings (see the Background section) can be made; therefore, 
these comments were not considered further. The remaining comments are 
addressed below.

Impact Analysis

General
    Comment 1: A commenter recommended that the Navy provide NMFS with 
an acoustics analysis that addresses noise impacts on land, from the 
air, and underwater. Full environmental analysis of the noise would 
examine a suite of metrics appropriate to the array of resources 
impacted. The impacts should discuss potential effects on wildlife, 
visitors, and other noise-sensitive receivers.
    The commenter also recommended that the Navy consider the following 
as it plans to conduct activities in the HSTT Study Area:

    <bullet> Use appropriate metrics to assess potential 
environmental impacts on land and water.
    <bullet> Determine natural ambient acoustic conditions as a 
baseline for analysis.
    <bullet> Assess effects from cumulative noise output, 
incorporating noise generated from other anthropogenic sources.
    <bullet> Determine distance at which noise will attenuate to 
natural levels.
    <bullet> Assess effects that these noise levels would have on 
terrestrial wildlife, marine wildlife, and visitors.
    <bullet> Appropriate and effective mitigation measures should be 
developed and used to reduce vessel strike (e.g., timing activities 
to avoid migration, and searching for marine

[[Page 66873]]

mammals before and during activities and taking avoidance measures).

    Response: NMFS refers the commenter to the HSTT FEIS/OEIS which 
conducts an assessment of all of the activities which comprise the 
proposed action and their impacts (including cumulative impacts) to 
relevant resources. The Navy is not required to do ambient noise 
monitoring or assess impacts to wildlife other than marine mammals or 
to visitors/tourists. The mitigation measures in the rule include 
procedural measures to minimize strike (avoiding whales by 500 yards, 
etc.), mitigation areas to minimize strike in biologically important 
areas, and Awareness Notification Message areas wherein all vessels are 
alerted to stay vigilant to the presence of large whales.
Density Estimates
    Comment 2. A commenter commented that 30 iterations or Monte Carlo 
simulations is low for general bootstrapping methods used in those 
models but understands that increasing the number of iterations in turn 
increases the computational time needed to run the models. Accordingly, 
the commenter suggested that the Navy consider increasing the 
iterations from 30 to at least 200 for activities that have yet to be 
modeled for upcoming MMPA rulemakings for Navy testing and training 
activities.
    Response: In areas where there are four season, 30 iterations are 
used in NAEMO which results in a total of 120 iterations per year for 
each event. However, in areas where only two seasons, warm and cold, 
the number of iterations per season is increased to 60 so that 120 
iterations per year are maintained. Navy reached this number of 
iterations by running two iterations of a scenario and calculating the 
mean of exposures, then running a third iteration and calculating the 
running mean of exposures, then a fourth iteration and so on. This is 
done until the running mean becomes stable. Through this approach, it 
was determined 120 iterations was sufficient to converge to a 
statistically valid answer and provides a reasonable uniformity of 
exposure predictions for most species and areas. There are a few 
exceptions for species with sparsely populated distributions or highly 
variable distributions. In these cases, the running mean may not 
flatten out (or become stable); however, there were so few exposures in 
these cases that while the mean may fluctuate, the overall number of 
exposures did not result in significant differences in the totals. In 
total, the number of simulations conducted for HSTT Phase III exceeded 
six million simulations and produced hundreds of terabytes of data. 
Increasing the number of iterations, based on the discussion above, 
would not result in a significant change in the results, but would 
incur a significant increase in resources (e.g., computational and 
storage requirements). This would divert these resources from 
conducting other more consequential analysis without providing for 
meaningfully improved data. The Navy has communicated that it is 
continually looking at ways to improve NAEMO and reduce data and 
computational requirements. As technologies and computational 
efficiencies improve, Navy will evaluate these advances and incorporate 
them where appropriate. NMFS has reviewed the Navy's approach and 
concurs that it is technically sound and reflects the best available 
science.
    Comment 3: A commenter had concerns regarding the Navy's pinniped 
density estimates. Given that a single density was provided for the 
respective areas and pinnipeds were assumed to occur at sea as 
individual animals, uncertainty does not appear to have been 
incorporated in the Navy's animat modeling for pinnipeds. The Navy 
primarily used sightings or abundance data, assuming certain correction 
factors, divided by an area to estimate pinniped densities. Many, if 
not all, of the abundance estimates had associated measures of 
uncertainty (i.e., coefficients of variation (CV), standard deviation 
(SD), or standard error (SE)). Therefore, the commenter recommended 
that NMFS require the Navy to specify whether and how it incorporated 
uncertainty in the pinniped density estimates into its animat modeling 
and if it did not, require the Navy to use measures of uncertainty 
inherent in the abundance data (i.e., CV, SD, SE) similar to the 
methods used for cetaceans.
    Response: As noted in the cited technical report Quantifying 
Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and 
Analytical Approach for Phase III Training and Testing (U.S. Department 
of the Navy, 2017a), the Navy did not apply statistical uncertainty 
outside the survey boundaries into non-surveyed areas, since it deemed 
application of statistical uncertainty would not be meaningful or 
appropriate. We note that there are no measures of uncertainty (i.e., 
no CV, SD, or SE) provided in NMFS Pacific Stock Assessment Report 
(SAR) Appendix 3 (Carretta et al., 2017) associated with the abundance 
data for any of the pinniped species present in Southern California or 
for monk seals in Hawaii. Although some measures of uncertainty are 
presented in some citations within the SAR and in other relevant 
publications for some survey findings, it is not appropriate for the 
Navy to attempt to derive summations of total uncertainty for an 
abundance when the authors of the cited studies and the SAR have not. 
For additional information regarding use of pinniped density data, see 
the cited U.S. Navy Marine Species Density Database Phase III for the 
Hawaii-Southern California Training and Testing Study Area Section 11 
(U.S. Department of the Navy, 2017b). As a result of the lack of 
published applicable measures of uncertainty for pinnipeds, the Navy 
did not incorporate measures of uncertainty into the pinniped density 
estimates. NMFS independently reviewed the methods and densities used 
by the Navy and concur that they are appropriate and reflect the best 
available science.
    Comment 4: A commenter had concerns regarding the various areas, 
abundance estimates, and correction factors that the Navy used for 
pinnipeds. The commenter referenced a lot of information in the context 
of both what the Navy used and what they could have used instead and 
summarizes the discussion with seven recommendations.
    For harbor seals, the area was based on the NMFS SOCAL stratum 
(extending to the extent of the U.S. exclusive economic zone (EEZ), 370 
km from the coast) for its vessel-based surveys (i.e., Barlow 2010) and 
the Navy applied the density estimates from the coast to 80-km 
offshore. The commenter believes that this approach is inappropriate 
and that the Navy should use the area of occurrence to estimate the 
densities for harbor seals. For harbor seals, the Navy assumed that 22 
percent of the stock occurred in SOCAL, citing Department of the Navy 
(2015). The commenter had two concerns with this approach. First, one 
has to go to Department of the Navy (2015) to determine the original 
source of the information (Lowry et al., 2008; see the commenter's 
February 20, 2014, letter on this matter). Second, Lowry et al. (2008) 
indicated that 23.3 percent of the harbor seal population occurred in 
SOCAL, not 22 percent as used by the Navy. Therefore, the commenter 
recommended that, at the very least, NMFS require the Navy to revise 
the pinniped density estimates using the extent of the coastal range 
(e.g., from shore to 80 km offshore) of harbor seals as the applicable 
area, 23.3 percent of the California abundance estimate based on Lowry 
et al. (2008), and an at-sea correction factor of 65 percent based on

[[Page 66874]]

Harvey and Goley (2011) for both seasons.
    For Monk seals the area was based on the areas within the 200-m 
isobaths in both the Main and Northwest Hawaiian Islands (MHI and NWHI, 
respectively) and areas beyond the 200-m isobaths in the U.S. EEZ. The 
commenter asserted that some of the abundances used were not based on 
best available science. The Navy noted that its monk seal abundance was 
less than that reported by Baker et al. (2016), but that those more 
recent data were not available when the Navy's modeling process began. 
The Baker et al. (2016) data have been available for almost two years 
and should have been incorporated accordingly, particularly since the 
data would yield greater densities and the species is endangered. For 
monk seals, the commenter recommended using the 2015 monk seal 
abundance estimate from Baker et al. (2016) and an at-sea correction 
factor of 63 percent for the MHI based on Baker et al. (2016) and 69 
percent for the NWHI based on Harting et al. (2017).
    For the northern fur seals, the area was based on the NMFS SOCAL 
stratum (extending to the extent of the U.S. EEZ, 370 km from the 
coast) for its vessel-based surveys (i.e., Barlow 2010). For elephant 
seals, California sea lions, and Guadalupe fur seals, the area was 
based on the Navy SOCAL modeling area. The commenter had concerns that 
these areas are not based on the biology or ecology of these species. 
The commenter recommended using the same representative area for 
elephant seals, northern fur seals, Guadalupe fur seals, and California 
sea lions. The commenter recommended using an increasing trend of 3.8 
percent annually for the last 15 years for elephant seals as part of 
the California population and at least 31,000 as representative of the 
Mexico population based on Lowry et al. (2014). Additionally, the 
commenter recommended using an at-sea correction factor of 44 percent 
for the cold season and 48 percent for the warm season for California 
sea lions based on Lowry and Forney (2005).
    Finally, the commenter recommended that NMFS require the Navy to 
(1) specify the assumptions made and the underlying data that were used 
for the at-sea correction factors for Guadalupe and northern fur seals 
and (2) consult with experts in academia and at the NMFS Science 
Centers to develop more refined pinniped density estimates that account 
for pinniped movements, distribution, at-sea correction factors, and 
density gradients associated with proximity to haul-out sites or 
rookeries.
    Response: The Navy provided additional clarification regarding the 
referenced concerns about areas, abundance estimates, and correction 
factors that were used for pinnipeds. We note that take estimation is 
not an exact science. There are many inputs that go into an estimate of 
marine mammal exposure, and the data upon which those inputs are based 
come with varying levels of uncertainty and precision. Also, 
differences in life histories, behaviors, and distributions of stocks 
can support different decisions regarding methods in different 
situations. Different methods may be supportable in different 
situations, and, further, there may be more than one acceptable method 
to estimate take in a particular situation. Accordingly, while NMFS 
always ensures that the methods are technically supportable and reflect 
the best available science, NMFS does not prescribe any one method for 
estimating take (or calculating some of the specific take estimate 
components that the commenter is concerned about). NMFS reviewed the 
areas, abundances, and correction factors used by the Navy to estimate 
take and concurs that they are appropriate. We note the following in 
further support of the analysis: While some of the suggestions the 
commenter makes could provide alternate valid ways to conduct the 
analyses, these modifications are not required in order to have equally 
valid and supportable analyses and, further, would not change NMFS' 
determinations for pinnipeds. In addition, we note that (1) many of the 
specific recommendations that the commenter makes are largely minor in 
nature: ``44 not 47 percent,'' ``63 not 61 percent,'' ``23.3 not 22 
percent'' or ``area being approximately 13 percent larger;'' and (2) 
even where the recommendation is somewhat larger in scale, given the 
ranges of these stocks, the size of the stocks, and the number and 
nature of pinniped takes, recalculating the estimated take for any of 
these pinniped stocks using the commenter's recommended changes would 
not change NMFS' assessment of impacts on the recruitment or survival 
of any of these stocks, or the negligible impact determination. Below, 
we address the Commenters issues in more detail and, while we do not 
explicitly note it in every section, NMFS has reviewed the Navy's 
analysis and choices in relation to these comments and concurs that 
they are technically sound and reflect the best available science.
    For harbor seals--Based on the results from satellite tracking of 
harbor seals at Monterey, California and the documented dive depths 
(Eguchi and Harvey, 2005), the extent of the range for harbor seals in 
the HSTT Study Area used by the Navy (a 50 nmi buffer around all known 
haul-out sites; approximately 93 km) is more appropriate than the 
suggested 80 km offshore suggested by commenter.
    The comment is incorrect in its claim that the Navy did not use the 
best available science. Regarding the appropriate percentage of the 
California Current Ecosystem abundance to assign to the HSTT Study 
Area, the 22 percent that the Navy used is based on the most recent of 
the two years provided in Lowry et al. (2008) rather than the mean of 
two years, which is one valid approach. Additionally, since 
approximately 74 percent of the harbor seal population in the Channel 
Islands (Lowry et al., 2017) is present outside and to the north of the 
HSTT Study Area, it is a reasonable assumption that the 22 percent used 
already provides a conservative overestimate and that it would not be 
appropriate to apply a higher percentage of the overall population for 
distribution into the Navy's modeling areas.
    Again the comment is incorrect in its claim that the correction 
factors applied to population estimates were either unsubstantiated or 
incorrect. Regarding the commenter's recommended use of an at-sea 
correction factor of 65 percent for both seasons based on Harvey and 
Goley (2011), that correction factor was specifically meant to apply to 
the single molting season when harbor seals are traditionally surveyed 
(see discussion in Lowry et al., 2017). Additionally, the authors of 
that study provided a correction factor (CF = 2.86; 35 percent) for 
Southern California but left open the appropriateness of that factor 
given the limited data available at the time. For these reasons, having 
separate correction factors for each of the seasons is more appropriate 
as detailed in Section 11.1.5 (Phoca vitulina, Pacific harbor seal) of 
the U.S. Navy Marine Species Density Database Phase III for the Hawaii-
Southern California Training and Testing Study Area (U.S. Department of 
the Navy, 2017b).
    For monk seals, as detailed in Section 11.1.4 (Neomonachus 
schauinslandi, Hawaiian monk seal) of the U.S. Navy Marine Species 
Density Database Phase III for the Hawaii-Southern California Training 
and Testing Study Area (U.S. Department of the Navy, 2017b), the Navy 
consulted with the researchers and subject matter experts at the 
Pacific Science Center and the Monk Seal Recovery Team regarding the 
abundance estimates, at sea correction factors, and distribution for 
monk seals in the Hawaiian Islands during development

[[Page 66875]]

of the HSTT FEIS/OEIS throughout 2015 and the Summer of 2016. The Navy 
incorporated the results of those consultations, including unpublished 
data, into the analysis of monk seals. Additional details in this 
regard to monk seal distributions and population trends as reflected by 
the abundance in the Hawaiian Islands are presented in the FEIS/OEIS in 
Section 3.7.2.2.9.2 (Habitat and Geographic Range) and Section 
3.7.2.2.9.3 (Population Trends). The Navy has indicated that it has 
continued ongoing communications with researchers at the Pacific 
Islands Science Center and elsewhere, has accounted for the findings in 
the citations noted by the commenter (Baker et al., 2016; Harting et 
al., 2017) as well as information in forthcoming publications provided 
ahead of publication via those researchers (cited as in preparation), 
and specifically asked for and received concurrence from subject matter 
experts regarding specific findings presented in the HSTT FEIS/OEIS 
regarding monk seals. The Navy also considered (subsequent to 
publication of the HSTT FEIS) the new Main Hawaiian Islands haulout 
correction factor presented in the publication by Wilson et al. (2017, 
which would be inconsistent with the use of the Baker et al. (2016) 
correction factors suggested by the commenter), and the Harting et al. 
(2017) correction factor, and has considered the new abundance numbers 
presented in the 2016 Stock Assessment Report, which first became 
available in January 2018. It is the Navy's assessment that a revision 
of the monk seal at-sea density would only result in small changes to 
the predicted effects and certainly would not change the conclusions 
presented in the HSTT FEIS/OEIS regarding impact on the population or 
the impact on the species. The Navy has communicated that it assumes 
that as part of the ongoing regulatory discussions with NMFS, changes 
to estimates of effects can be best dealt with in the next rulemaking 
given Wilson et al. (2017) has now also provided a totally new haulout 
correction factor for the Main Hawaiian Islands that was not considered 
in Baker et al. (2016), Harting et al. (2017), or the 2016 SAR.
    For northern fur seals, elephant seals, California sea lions, and 
Guadalupe fur seals, the Navy consulted with various subject matter 
experts regarding the abundances and distributions used in the HSTT 
FEIS/OEIS analyses for these species and based on those consultations 
and the literature available, the Navy and NMFS believe that the 
findings presented in the HSTT FEIS/OEIS and supporting technical 
reports provide the most accurate assessments available for these 
species. Given the demonstrated differences in the at-sea distributions 
of elephant seals, northern fur seals, Guadalupe fur seals, and 
California sea lions (Gearin et al., 2017; Lowry et al., 2014; Lowry,et 
al., 2017; Norris, 2017; Norris,et al., 2015; Robinson et al., 2012; 
University of California Santa Cruz and National Marine Fisheries 
Service, 2016), it would not be appropriate to use the same 
representative area for distributions of these species' population 
abundances. For example, California sea lions forage predominantly 
within 20 nautical miles from shore (Lowry and Forney, 2005), while tag 
data shows that many elephant seals (Robinson et al., 2012) and 
Guadalupe fur seals (Norris, 2017) seasonally forage in deep waters of 
the Pacific well outside the boundaries of the HSTT Study Area.
    For northern elephant seals (Mirounga angustirostris, Northern 
elephant seal), as detailed in Section 11.1.3 of the technical report 
titled U.S. Navy Marine Species Density Database Phase III for the 
Hawaii-Southern California Training and Testing Study Area (U.S. 
Department of the Navy, 2017e), hereafter referred to as the Density 
Technical Report, the Navy considered a number of factors in the 
development of the data for this species, including the fact that not 
all of the elephant seal population is likely to occur exclusively 
within the Southern California portion of the HSTT Study Area. Given 
that the three main rookeries considered in this analysis are located 
at the northern boundary of the HSTT Study Area and that elephant seals 
migrate northward after the breeding season, the Navy, in consultation 
with subject matter experts, believes the current abundance used in the 
analysis is based on the best available science and represents a 
conservative overestimate of the number of elephant seals likely to be 
affected by Navy activities in the HSTT Study Area.
    For California sea lions, the citation (Lowry and Forney, 2005) 
used as the basis for this recommendation specifically addressed the 
use of the Central and Northern California at-sea correction factor 
elsewhere, with the authors stating; ``In particular, [use of the 
Central and Northern California at-sea correction factor] would not be 
appropriate for regions where sea lions reproduce, such as in the 
Southern California Bight (SCB) and in Mexico, . . .'' Given the waters 
of the Southern California Bight and off Mexico overlap the HSTT Study 
Area and since the authors of the cited study specifically recommended 
not using the correction factor in the manner the commenter suggested, 
the Navy does not believe use of that correction factor for the HSTT 
Study Area would be appropriate. NMFS concurs with this approach
    For Guadalupe fur seal--Additional detail regarding the data used 
for the analysis of Guadalupe fur seals has been added to the HSTT 
Final EIS/OEIS Section 3.7.2.2.8 (Arctocephalus townsendi, Guadalupe 
Fur Seal). The Navy had integrated the latest (September 2017) 
unpublished data for Guadalupe fur seals from researchers in the United 
States and Mexico into the at-sea correction factor and density 
distribution of the species used in the modeling, but consultations 
with experts in academia and at the NMFS Science Centers and their 
recommendations had not been finalized before release of the Draft EIS/
OEIS. Subsequently, the Navy did not consider this revision of the text 
critical for the final NEPA document since the new data did not provide 
any significant change to the conclusions reached regarding the 
Guadalupe fur seal population. In fact, the data indicates an increase 
in the population and expansion of their range concurrent with decades 
of ongoing Navy training and testing in the SOCAL range complex.
    For Northern Fur Seal--As presented in Section 11.1.2 (Callorhinus 
ursinus, Northern fur seal) of the Navy's Density Technical Report 
(U.S. Department of the Navy, 2017b), the correction factor percentages 
for northern fur seals potentially at sea were derived from the 
published literature as cited (Antonelis, Stewart, & Perryman, 1990; 
Ream, Sterling, & Loughlin, 2005; Roppel, 1984).
    For future EISs, the Navy explained that it did and will continue 
to consult with authors of the papers relevant to the analyses as well 
as other experts in academia and at the NMFS Science Centers during the 
development of the Navy's analyses. During the development of the HSTT 
EIS/OEIS and as late as September 2017, the Navy had ongoing 
communications with various subject matter experts and specifically 
discussed pinniped movements, the distribution of populations within 
the study area to support the analyses, the pinniped haulout or at-sea 
correction factors, and the appropriateness of density gradients 
associated with proximity to haul-out sites or rookeries. As shown in 
the references cited, the personal communications with researchers have 
been made part of the public record, although many other

[[Page 66876]]

informal discussions with colleagues have also assisted in the Navy's 
approach to the analyses presented.
    The Navy acknowledges that there have been previous comments 
provided by this commenter on other Navy range complex documents 
regarding the use of satellite tag movement and location data to derive 
at-sea pinniped density data, and the Navy asserts that previous 
responses to those comments remain valid. Additionally, the commenter 
has noted that the ``. . . Commenter continues to believe that data 
regarding movements and dispersion of tagged pinnipeds could yield 
better approximations of densities than the methods the Navy currently 
uses.'' The Navy acknowledges that in comments to previous Navy EIS/
OEIS analyses, the commenter has recommended this untried approach; 
responses to those previous comments have been provided. The Navy also 
notes that there have been papers suggesting the future application of 
Bayesian or Markov chain techniques for use in habitat modeling (e.g., 
Redfern et al., 2006) and overcoming the bias introduced by 
interpretation of population habitat use based on non-randomized 
tagging locations (e.g., Whitehead & Jonsen, 2013). However, the use of 
satellite tag location data in a Bayesian approach to derive cetacean 
or pinniped densities at sea has yet to be accepted, implemented, or 
even introduced in the scientific literature.
    This issue was in fact recently discussed as part of the Density 
Modeling Workshop associated with the October 2017 Society for Marine 
Mammalogy conference. The consensus of the marine mammal scientists 
present was that while pinniped tag data could provide a good test 
case, it realistically was unlikely to be a focus of the near-term 
research. The working group determined that a focused technical group 
should be established to specifically discuss pinnipeds and data 
available for density surface modelling in the future. It was also 
discussed at the Density Modeling Workshop in October 2018. The Navy 
has convened a pinniped working group and NMFS ASFSC is sponsoring a 
demonstration project to use haulout and telemetry data from seals in 
Alaska to determine the viability of such an approach.
    Therefore, consistent with previous assessments and based on recent 
discussions with subject matter experts in academia, the NMFS Science 
Centers, and the National Marine Mammal Laboratory, and given there is 
no currently established methodology for implementing the approach 
suggested by the commenter, the Navy believes that attempting to create 
and apply a new density derivation method at this point would introduce 
additional levels of uncertainty into density estimations.
    For these reasons, the Navy and NMFS will not provide density 
estimates based on pinniped tracking data. Publications reporting on 
satellite tag location data have been and will continue to be used to 
aid in the understanding of pinniped distributions and density 
calculations as referenced in the FEIS/OEIS and the U.S. Navy Marine 
Species Density Database Phase III for the Hawaii-Southern California 
Training and Testing Study Area (U.S. Department of the Navy, 2017b). 
The Navy has communicated that it will continue, as it has in the past, 
to refine pinniped density and distributions using telemetry data and 
evolving new techniques (such as passive acoustic survey data) in 
development of the Navy's analyses. As noted above, NMFS has reviewed 
the Navy's methods and concurs that they are appropriate and reflect 
the best available science.
    Comment 5: A commenter recommended that NMFS require the Navy to 
(1) specify what modeling method and underlying assumptions, including 
any relevant source spectra and assumed animal swim speeds and turnover 
rates, were used to estimate the ranges to PTS and TTS for impact and 
vibratory pile-driving activities, (2) accumulate the energy for the 
entire day of proposed activities to determine the ranges to PTS and 
TTS for impact and vibratory pile-driving activities, and (3) clarify 
why the PTS and TTS ranges were estimated to be the same for LF and HF 
cetaceans during impact pile driving.
    Response: As explained in Section 3.7.3.1.4.1 of the HSTT FEIS/
OEIS, the Navy measured values for source levels and transmission loss 
from pile driving of the Elevated Causeway System, the only pile 
driving activity included in the Specified Activity. The Navy reviewed 
the source levels and how the spectrum was used to calculate the range 
to effects; NMFS supports the use of these measured values. These 
recorded source waveforms were weighted using the auditory weighting 
functions. Low-frequency and high-frequency cetaceans have similar 
ranges for impact pile driving since low-frequency cetaceans would be 
relatively more sensitive to the low-frequency sound which is below 
high-frequency cetaceans' best range of hearing. Neither the NMFS user 
spreadsheet nor NAEMO were required for calculations. An area density 
model was developed in MS Excel which calculated zones of influence 
(ZOI) to thresholds of interest (e.g., behavioral response) based on 
durations of pile driving and the aforementioned measured and weighted 
source level values. The resulting area was then multiplied by density 
of each marine mammal species that could occur within the vicinity. 
This produced an estimated number of animals that could be impacted per 
pile, per day, and overall during the entire activity for both the 
impact pile driving and vibratory removal phases. NOAA HQ scientists 
involved in the acoustic criteria development reviewed the manner in 
which the Navy applied the frequency weighting and calculated all 
values and concurred with the approach.
    Regarding the appropriateness of accumulating energy for the entire 
day, based on the best available science regarding animal reaction to 
sound, selecting a reasonable SEL calculation period is necessary to 
more accurately reflect the time period an animal would likely be 
exposed to the sound. The Navy factored both mitigation effectiveness 
and animal avoidance of higher sound levels into the impact pile 
driving analysis. For impact pile driving, the mitigation zone extends 
beyond the average ranges to PTS for all hearing groups; therefore, 
mitigation will help prevent or reduce the potential for exposure to 
PTS. The impact pile driving mitigation zone also extends beyond or 
into a portion of the average ranges to TTS; therefore, mitigation will 
help prevent or reduce the potential for exposure to all TTS or some 
higher levels of TTS, depending on the hearing group. Mitigation 
effectiveness and animal avoidance of higher sound levels were both 
factored into the impact pile driving analysis as most marine mammals 
should be able to easily move away from the expanding ensonified zone 
of TTS/PTS within 60 seconds, especially considering the soft start 
procedure, or avoid the zone altogether if they are outside of the 
immediate area upon startup. Marine mammals are likely to leave the 
immediate area of pile driving and extraction activities and be less 
likely to return as activities persist. However, some ``naive'' animals 
may enter the area during the short period of time when pile driving 
and extraction equipment is being re-positioned between piles. 
Therefore, an animal ``refresh rate'' of 10 percent was selected. This 
means that 10 percent of the single pile ZOI was added for each 
consecutive pile within a given 24-hour period to generate the daily 
ZOI per effect category. These daily ZOIs were then multiplied by the 
number of days of pile driving and pile extraction and

[[Page 66877]]

then summed to generate a total ZOI per effect category (i.e., 
behavioral response, TTS, PTS). The small size of the mitigation zone 
and its close proximity to the observation platform will result in a 
high likelihood that Lookouts would be able to detect marine mammals 
throughout the mitigation zone.
PTS/TTS Thresholds
    Comment 6: A commenter supported the weighting functions and 
associated thresholds as stipulated in Finneran (2016), which are the 
same as those used for Navy Phase III activities, but points to 
additional recent studies that provide additional behavioral audiograms 
(e.g., Branstetter et al. 2017; Kastelein et al. 2017b) and information 
on TTS (e.g., Kastelein et al. 2017a, 2017c). However, they commented 
that the Navy should provide a discussion of whether those new data 
corroborate the current weighting functions and associated thresholds.
    Response: The NMFS Revised Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (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, including the articles that 
the commenter referenced that were published subsequent to the 
publication of the first version of 2016 Acoustic Technical Guidance. 
The new data included in those articles are consistent with the 
thresholds and weighting functions included in the current version of 
the Acoustic Technical Guidance (NMFS 2018).
    NMFS will continue to review and evaluate new relevant data as it 
becomes available and consider the impacts of those studies on the 
Acoustic Technical Guidance to determine what revisions/updates may be 
appropriate. Thus far, no new information has been published or 
otherwise conveyed that would fundamentally change the assessment of 
impacts or conclusions of this rule.
    Comment 7: Commenters commented that the criteria that the agency 
has produced to estimate temporary threshold shift (TTS) and permanent 
threshold shift (PTS) in marine mammals are erroneous and non-
conservative. Commenters cited multiple purported issues with NMFS' 
Acoustic Technical Guidance, such as pseudo-replication and 
inconsistent treatment of data, broad extrapolation from a small number 
of individuals, and disregarding ``non-linear accumulation of 
uncertainty.'' Commenters suggested that NMFS not rely exclusively on 
its auditory guidance for determining Level A harassment take, but 
should at a minimum retain the historical 180-dB rms Level A harassment 
threshold as a ``conservative upper bound'' or conduct a ``sensitivity 
analysis'' to ``understand the potential magnitude'' of the supposed 
errors.
    Response: NMFS disagrees with this characterization of the Acoustic 
Technical Guidance and the associated recommendation. The Acoustic 
Technical Guidance is a compilation, interpretation, and synthesis of 
the scientific literature that provides the best scientific information 
regarding the effects of anthropogenic sound on marine mammals' 
hearing. The technical guidance was classified as a Highly Influential 
Scientific Assessment and, as such, underwent three independent peer 
reviews, at three different stages in its development, including a 
follow-up to one of the peer reviews, prior to its dissemination by 
NMFS. In addition, there were three separate public comment periods, 
during which time we received and responded to similar comments on the 
guidance (81 FR 51694), which we cross-reference here, and more recent 
public and interagency review under Executive Order 13795. This review 
process was scientifically rigorous and ensured that the Guidance 
represents the best scientific data available.
    The Acoustic Technical Guidance updates the historical 180 dB rms 
injury threshold, which was based on professional judgement (i.e., no 
data were available on the effects of noise on marine mammal hearing at 
the time this original threshold was derived). NMFS disagrees with any 
suggestion that the use of the Acoustic Technical Guidance provides 
erroneous results. The 180-dB rms threshold is plainly outdated, as the 
best available science indicates that rms SPL is not even an 
appropriate metric by which to gauge potential auditory injury (whereas 
the scientific debate regarding behavioral harassment thresholds is not 
about the proper metric but rather the proper level or levels and how 
these may vary in different contexts).
    Multiple studies from humans, terrestrial mammals, and marine 
mammals have demonstrated less TTS from intermittent exposures compared 
to continuous exposures with the same total energy because hearing is 
known to experience some recovery in between noise exposures, which 
means that the effects of intermittent noise sources such as tactical 
sonars are likely overestimated. Marine mammal TTS data have also shown 
that, for two exposures with equal energy, the longer duration exposure 
tends to produce a larger amount of TTS. Most marine mammal TTS data 
have been obtained using exposure durations of tens of seconds up to an 
hour, much longer than the durations of many tactical sources (much 
less the continuous time that a marine mammal in the field would be 
exposed consecutively to those levels), further suggesting that the use 
of these TTS data are likely to overestimate the effects of sonars with 
shorter duration signals.
    Regarding the suggestion of pseudo-replication and erroneous 
models, since marine mammal hearing and noise-induced hearing loss data 
are limited, both in the number of species and in the number of 
individuals available, attempts to minimize pseudoreplication would 
further reduce these already limited data sets. Specifically, with 
marine mammal behavioral temporary threshold shift studies, 
behaviorally derived data are only available for two mid-frequency 
cetacean species (bottlenose dolphin, beluga) and two phocids (in-
water) pinniped species (harbor seal and northern elephant seal), with 
otariid (in-water) pinnipeds and high-frequency cetaceans only having 
behaviorally-derived data from one species. Arguments from Wright 
(2015) regarding pseudoreplication within the TTS data are therefore 
largely irrelevant in a practical sense because there are so few data. 
Multiple data points were not included for the same individual at a 
single frequency. If multiple data existed at one frequency, the lowest 
TTS onset was always used. There is only a single frequency where TTS 
onset data exist for two individuals of the same species: 3 kHz for 
dolphins. Their TTS (unweighted) onset values were 193 and 194 dB re 1 
[mu]Pa2s. Thus, NMFS believes that the current approach makes the best 
use of the given data. Appropriate means of reducing pseudoreplication 
may be considered in the future, if more data become available. Many 
other comments from Wright (2015) and the comments from Racca et al. 
(2015b) appear to be erroneously based on the idea that the shapes of 
the auditory weighting functions and TTS/PTS exposure thresholds are 
directly related to the audiograms; i.e., that changes to the composite 
audiograms would directly influence the TTS/PTS exposure functions 
(e.g., Wright (2015) describes weighting functions as ``effectively the 
mirror image of an audiogram'' (p. 2) and states, ``The underlying goal 
was to estimate how

[[Page 66878]]

much a sound level needs to be above hearing threshold to induce TTS.'' 
(p. 3)). Both statements are incorrect and suggest a fundamental 
misunderstanding of the criteria/threshold derivation. This would 
require a constant (frequency-independent) relationship between hearing 
threshold and TTS onset that is not reflected in the actual marine 
mammal TTS data. Attempts to create a ``cautionary'' outcome by 
artificially lowering the composite audiogram thresholds would not 
necessarily result in lower TTS/PTS exposure levels, since the exposure 
functions are to a large extent based on applying mathematical 
functions to fit the existing TTS data.
Behavioral Harassment Thresholds
    Comment 8: Commenters commented on what it asserts is NMFS' failure 
to set proper thresholds for behavioral impacts. Referencing the 
biphasic function that assumes an unmediated dose response relationship 
at higher received levels and a context-influenced response at lower 
received levels that NMFS uses to quantify behavioral harassment from 
sonar, Commenters commented that resulting functions depend on some 
inappropriate assumptions that tend to significantly underestimate 
effects. Commenters expressed concern that every data point that 
informs the agency's pinniped function, and nearly two-thirds of the 
data points informing the odontocete function (30/49), are derived from 
a captive animal study. Additionally, Commenters asserted that the risk 
functions do not incorporate (nor does NMFS apparently consider) a 
number of relevant studies on wild marine mammals. Commenters stated 
that it is not clear from the proposed rule, or from the Navy's recent 
technical report on acoustic ``criteria and thresholds,'' on which 
NMFS' approach in the rule is based, exactly how each of the studies 
that NMFS employed was applied in the analysis, or how the functions 
were fitted to the data, but the available evidence on behavioral 
response raises concerns that the functions are not conservative for 
some species. Commenters recommended NMFS make additional technical 
information available, including from any expert elicitation and peer 
review, so that the public can fully comment.
    Response: The Criteria and Thresholds for U.S. Navy Acoustic and 
Explosive Impacts to Marine Mammals and Sea Turtles Technical Report 
(U.S. Department of the Navy, 2017) details how the Navy's proposed 
method, which was determined appropriate and adopted by NMFS, accounted 
for the differences in captive and wild animals in the development of 
the behavioral response functions. The Navy used the best available 
science, which has been reviewed by external scientists and approved by 
NMFS, in the analysis. The Navy and NMFS have utilized all available 
data that relate known or estimable received levels to observations of 
individual or group behavior as a result of sonar exposure (which is 
needed to inform the behavioral response function) for the development 
of updated thresholds. Limiting the data to the small number of field 
studies that include these necessary data would not provide enough data 
with which to develop the new risk functions. In addition, NMFS agrees 
with the assumptions made by the Navy, including the fact that captive 
animals may be less sensitive, in that the scale at which a moderate to 
severe response was considered to have occurred is different for 
captive animals than for wild animals, as the agency understands those 
responses will be different.
    The new risk functions were developed in 2016, before several 
recent papers were published or the data were available. As new science 
is published, NMFS and the Navy continue to evaluate the information. 
The thresholds have been rigorously vetted among scientists and within 
the Navy community during expert elicitation and then reviewed by the 
public before being applied. It is unreasonable to revise and update 
the criteria and risk functions every time a new paper is published. 
These new and future papers provide additional information, and the 
Navy has already begun to consult them for updates to the thresholds in 
the future, when the next round of updated criteria will be developed. 
Thus far, no new information has been published or otherwise conveyed 
that would fundamentally change the assessment of impacts or 
conclusions of the HSTT FEIS/OEIS or this rule. To be included in the 
behavioral response function, data sets need to relate known or 
estimable received levels to observations of individual or group 
behavior. Melcon et al. (2012) does not relate observations of 
individual/group behavior to known or estimable received levels (at 
that individual/group). In Melcon et al. (2012), received levels at the 
HARP buoy averaged over many hours are related to probabilities of D-
calls, but the received level at the blue whale individuals/group are 
unknown.
    As noted, the derivation of the behavioral response functions is 
provided in the 2017 technical report titled Criteria and Thresholds 
for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III). The 
appendices to this report detail the specific data points used to 
generate the behavioral response functions. Data points come from 
published data that is readily available and cited within the technical 
report.
    Comment 9: Commenters stated concerns with the use of distance 
``cut-offs'' in the behavioral harassment thresholds, and one commenter 
recommended that NMFS refrain from using cut-off distances in 
conjunction with the Bayesian BRFs and re-estimate the numbers of 
marine mammal takes based solely on the Bayesian BRFs.
    Response: The consideration of proximity (cut-off distances) was 
part of the criteria developed in consultation between the Navy and 
NMFS, is appropriate based on the best available science which shows 
that marine mammal responses to sound vary based on both sound level 
and distance, and was applied within the Navy's acoustic effects model. 
The derivation of the behavioral response functions and associated cut-
off distances is provided in the 2017 technical report titled Criteria 
and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis 
(Phase III). To account for non-applicable contextual factors, all 
available data on marine mammal reactions to actual Navy activities and 
other sound sources (or other large scale activities such as seismic 
surveys when information on proximity to sonar sources is not available 
for a given species group) were reviewed to find the farthest distance 
to which significant behavioral reactions were observed. These 
distances were rounded up to the nearest 5 or 10 km interval, and for 
moderate to large scale activities using multiple or louder sonar 
sources, these distances were greatly increased--doubled in most cases. 
The Navy's BRFs applied within these distances provide technically 
sound methods reflective of the best available science to estimate of 
impact and potential take under military readiness for the actions 
analyzed within the HSTT FEIS/OEIS and included in these regulations. 
NMFS has independently assessed the Navy's behavioral harassment 
thresholds and believes that they appropriately apply the best 
available science and it is not necessary to recalculate take 
estimates.
    The commenter also specifically expressed concern that distance 
``cut-offs'' alleviate some of the exposures that would otherwise have 
been counted if the received level alone were considered. It is unclear 
why the commenter finds this inherently inappropriate, as this is what 
the data show. As noted previously, there are

[[Page 66879]]

multiple studies illustrating that in situations where one would expect 
a behavioral harassment because of the received levels at which 
previous responses were observed, it has not occurred when the distance 
from the source was larger than the distance of the first observed 
response.
    Comment 10: Regarding cut-off distances, Commenters noted that 
dipping sonar appears to be a significant predictor of deep-dive rates 
in beaked whales on Southern California Anti-submarine Warfare Range 
(SOAR), with the dive rate falling significantly (e.g., to 35 percent 
of that individual's control rate) during sonar exposure, and likewise 
appears associated with habitat abandonment. Importantly, these effects 
were observed at substantially greater distances (e.g., 30 or more km) 
from dipping sonar than would otherwise be expected given the systems' 
source levels and the beaked whale response thresholds developed from 
research on hull-mounted sonar. Commenters suggested that the analysis, 
and associated cut-off distances, do not properly consider the impacts 
of dipping sonar.
    Response: The Navy relied upon the best science that was available 
to develop the behavioral response functions in consultation with NMFS. 
The Navy's current beaked whale BRF acknowledges and incorporates the 
increased sensitivity observed in beaked whales during both behavioral 
response studies and during actual Navy training events, as well as the 
fact that dipping sonar can have greater effects than some other 
sources with the same source level. Specifically, the distance cut-off 
for beaked whales is 50 km, larger than any other group. Moreover, 
although dipping sonar has a significantly lower source level than 
hull-mounted sonar, it is included in the category of sources with 
larger distance cut-offs, specifically in acknowledgement of its 
unpredictability and association with observed effects. This means that 
``takes'' are reflected at lower received levels that would have been 
excluded because of the distance for other source types.
    The referenced article (Associating patterns in movement and diving 
behavior with sonar use during military training exercises: A case 
study using satellite tag data from Cuvier's beaked whales at the 
Southern California Anti-submarine Warfare Range (Falcone et al., 2017) 
was not available at the time the BRFs were developed. However, NMFS 
and the Navy have reviewed the article and concur that neither this 
article nor any other new information that has been published or 
otherwise conveyed since the proposed rule was published would 
significantly change the assessment of impacts or conclusions in the 
HSTT FEIS/OEIS or in this rulemaking. Nonetheless, the new information 
and data presented in the new article were recently thoroughly reviewed 
by the Navy and will be quantitatively incorporated into future 
behavioral response functions, as appropriate for data available at the 
time that new functions are needed to inform new analyses.
    Furthermore, ongoing Navy funded beaked whale monitoring at the 
same site where the dipping sonar tests were conducted has not 
documented habitat abandonment by beaked whales. Passive acoustic 
detections of beaked whales have not significantly changed over eight 
years of monitoring (DiMarzio et al., 2018). From visual surveys in the 
area since 2006 there have been repeated sightings of: The same 
individual beaked whale, beaked whale mother-calf pairs, and beaked 
whale mother-calf pairs with mothers on their second calf (Schorr et 
al., 2018). Satellite tracking studies of beaked whale documented high 
site fidelity to this area (Schorr et al., 2018).''
    Comment 11: Regarding the behavioral thresholds for explosives, 
Commenters recommended that NMFS estimate and ultimately authorize 
behavior takes of marine mammals during all explosive activities, 
including those that involve single detonations.
    Response: The derivation of the explosive injury criteria is 
provided in the 2017 technical report titled Criteria and Thresholds 
for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III), and 
NMFS has applied the general rule a commenter referenced to single 
explosives for years, i.e., that marine mammals are unlikely to respond 
to a single instantaneous detonation in a manner that would rise to the 
level of a take. Neither NMFS nor the Navy are aware of evidence to 
support the assertion that animals will have significant behavioral 
reactions (i.e., those that would rise to the level of a take) to 
temporally and spatially isolated explosions. The Navy has been 
monitoring detonations since the 1990s and has not observed these types 
of reactions. TTS and all other higher order impacts are assessed for 
all training and testing events that involve the use of explosives or 
explosive ordnance.
    Further, to clarify, the current take estimate framework does not 
preclude the consideration of animals being behaviorally disturbed 
during single explosions as they are counted as ``taken by Level B 
harassment'' if they are exposed above the TTS threshold, which is only 
5 dB higher than the behavioral harassment threshold. We acknowledge in 
our analysis that individuals exposed above the TTS threshold may also 
be behaviorally harassed and those potential impacts are considered in 
the negligible impact determination.
    All of the Navy's monitoring projects, reports, and publications 
are available on the marine species monitoring web page (https://www.navymarinespeciesmonitoring.us/). NMFS will continue to review 
applicable monitoring and science data and consider modifying these 
criteria when and if new information suggests it is appropriate.
Mortality and injury thresholds for explosions
    Comment 12: A commenter recommended that NMFS require the Navy to 
(1) explain why the constants and exponents for onset mortality and 
onset slight lung injury thresholds for Phase III have been amended, 
(2) ensure that the modified equations are correct, and (3) specify any 
additional assumptions that were made.
    Response: The derivation of the explosive injury equations, 
including any assumptions, is provided in the 2017 technical report 
titled Criteria and Thresholds for U.S. Navy Acoustic and Explosive 
Effects Analysis (Phase III). It is our understanding that the 
constants and exponents for onset mortality and onset slight lung 
injury were amended by the Navy since Phase II to better account for 
the best available science. Specifically, the equations were modified 
in Phase III to fully incorporate the injury model in Goertner (1982), 
specifically to include lung compression with depth. NMFS independently 
reviewed and concurred with this approach.
    Comment 13: A commenter commented that the Navy only used the onset 
mortality and onset slight lung injury criteria to determine the range 
to effects, while it used the 50 percent mortality and 50 percent 
slight lung injury criteria to estimate the numbers of marine mammal 
takes. The commenter believes that this approach is inconsistent with 
the manner in which the Navy estimated the numbers of takes for PTS, 
TTS, and behavior for explosive activities. All of those takes have 
been and continue to be based on onset, not 50-percent values. The 
commenter commented on circumstances of the deaths of multiple common 
dolphins during one of the Navy's underwater detonation events in March 
2011 (Danil and St. Leger, 2011)

[[Page 66880]]

and indicated that the Navy's mitigation measures are not fully 
effective, especially for explosive activities. The commenter believes 
it would be more prudent for the Navy to estimate injuries and 
mortalities based on onset rather than a 50-percent incidence of 
occurrence. The Navy did indicate that it is reasonable to assume for 
its impact analysis--thus its take estimation process--that extensive 
lung hemorrhage is a level of injury that would result in mortality for 
a wild animal (Department of the Navy 2017a). Thus, the commenter 
comments that it is unclear why the Navy did not follow through with 
that premise. The commenter recommends that NMFS use onset mortality, 
onset slight lung injury, and onset GI tract injury thresholds to 
estimate both the numbers of marine mammal takes and the respective 
ranges to effect.
    Response: Based on an extensive review of the incident referred to 
by the commenter, in coordination with NMFS the Navy revised and 
updated the mitigation for these types of events. There have been no 
further incidents since these mitigation changes were instituted in 
2011.
    The Navy used the range to one percent risk of mortality and injury 
(referred to as ``onset'' in the Draft EIS/OEIS) to inform the 
development of mitigation zones for explosives. In all cases, the 
mitigation zones for explosives extend beyond the range to one percent 
risk of non-auditory injury, even for a small animal (representative 
mass = 5 kg). In the FEIS/OEIS, the Navy has clarified that the 
``onset'' non-auditory injury and mortality criteria are actually one 
percent risk criteria.
    Over-predicting impacts, which would occur with the use of one 
percent non-auditory injury risk criteria in the quantitative analysis, 
would not afford extra protection to any animal. The Navy, in 
coordination with NMFS, has determined that the 50 percent incidence of 
occurrence is a reasonable representation of a potential effect and 
appropriate for take estimation.
    Although the commenter implies that the Navy did not use extensive 
lung hemorrhage as indicative of mortality, that statement is 
incorrect. Extensive lung hemorrhage is assumed to result in mortality, 
and the explosive mortality criteria are based on extensive lung injury 
data See the 2017 technical report titled Criteria and Thresholds for 
U.S. Navy Acoustic and Explosive Effects Analysis (Phase III).
Range to Effects
    Comment 14: One commenter noted that regarding TTS, the ranges to 
effect provided in Table 25 of the Federal Register notice of proposed 
rulemaking and Table 6-4 of the LOA application appear to be incorrect. 
The ranges for LF cetaceans should increase with increasing sonar 
emission time. Therefore, the commenter recommended that NMFS determine 
what the appropriate ranges to TTS for bin LF5 should be and amend the 
ranges for the various functional hearing groups in the tables 
accordingly.
    Response: The error in the table has been fixed; specifically, the 
ranges for MF cetaceans have been revised. Note that the distances are 
shorter than initially provided in the proposed rule, indicating that 
the impacts of exposure to this bin are fewer than initially implied by 
the table. Regardless, the error was only associated with the 
information presented in this table; there was no associated error in 
any distances used in the take estimation, and both the take estimates 
and our findings remain the same.
Mitigation and Avoidance Calculations
    Comment 15: Commenters cited concerns that there was not enough 
information by which to evaluate the Navy's post-modeling calculations 
to account for mitigation and avoidance and imply that Level A takes 
and mortality takes may be underestimated. A commenter recommended that 
NMFS (1) authorize the total numbers of model-estimated Level A 
harassment (PTS) and mortality takes rather than reduce the estimated 
numbers of takes based on the Navy's post-model analyses and (2) use 
those numbers, in addition to the revised Level B harassment takes, to 
inform its negligible impact determination analyses.
    Response: The consideration of marine mammal avoidance and 
mitigation effectiveness is integral to the Navy's overall analysis of 
impacts from sonar and explosive sources. NMFS has independently 
evaluated the method and agrees that it is appropriately applied to 
augment the model in the prediction and authorization of injury and 
mortality as described in the rule. Details of this analysis are 
provided in the Navy's 2018 technical report titled Quantifying 
Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and 
Analytical Approach for Phase III Training and Testing; additional 
information on the mitigation analysis also has been included in the 
final rule.
    Sound levels diminish quickly below levels that could cause PTS. 
Studies have shown that all animals observed avoid areas well beyond 
these zones; therefore, the vast majority of animals are likely to 
avoid sound levels that could cause injury to their ear. As discussed 
in the Navy's 2018 technical report titled Quantifying Acoustic Impacts 
on Marine Mammals and Sea Turtles: Methods and Analytical Approach for 
Phase III Training and Testing, animats in the Navy's acoustic effects 
model do not move horizontally or ``react'' to sound in any way. The 
current best available science based on a growing body of behavioral 
response research shows that animals do in fact avoid the immediate 
area around sound sources to a distance of a few hundred meters or more 
depending upon the species. Avoidance to this distance greatly reduces 
the likelihood of impacts to hearing such as TTS and PTS.
    Specifically, behavioral response literature, including the recent 
3S and SOCAL BRS studies, indicate that the multiple species from 
different cetacean suborders do in fact avoid approaching sound sources 
by a few hundred meters or more, which would reduce received sound 
levels for individual marine mammals to levels below those that could 
cause PTS. The ranges to PTS for most marine mammal groups are within a 
few tens of meters and the ranges for the most sensitive group, the HF 
cetaceans, average about 200 m, to a maximum of 270 m in limited cases.
    As discussed in the Navy's 2018 technical report titled Quantifying 
Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and 
Analytical Approach for Phase III Training and Testing, the Navy's 
acoustic effects model does not consider procedural mitigations (i.e., 
power-down or shut-down of sonars, or pausing explosive activities when 
animals are detected in specific zones adjacent to the source), which 
necessitates consideration of these factors in the Navy's overall 
acoustic analysis. Credit taken for mitigation effectiveness is 
extremely conservative. For example, if Lookouts can see the whole 
area, they get credit for it in the calculation; if they can see more 
than half the area, they get half credit; if they can see less than 
half the area, they get no credit. Not considering animal avoidance and 
mitigation effectiveness would lead to a great overestimate of 
injurious impacts. NMFS concurs with the analytical approach used, 
i.e., we believe the estimated Level A take numbers represent the 
maximum number of these takes that are likely to occur and it would not 
be appropriate to authorize a higher number or consider a higher number 
in the negligible impact analysis.

[[Page 66881]]

    Last, the Navy's 2018 technical report titled Quantifying Acoustic 
Impacts on Marine Mammals and Sea Turtles: Methods and Analytical 
Approach for Phase III Training and Testing very clearly explains in 
detail how species sightability, the Lookout's ability to observe the 
range to PTS (for sonar and other transducers) and mortality (for 
explosives), the portion of time when mitigation could potentially be 
conducted during periods of reduced daytime visibility (to include 
inclement weather and high sea state) and the portion of time when 
mitigation could potentially be conducted at night, and the ability for 
sound sources to be positively controlled (powered down) are considered 
in the post-modeling calculation to account for mitigation and 
avoidance. It is not necessary to view the many tables of numbers 
generated in the assessment to evaluate the method.
    Comment 16: A commenter stated in regards to the method in which 
the Navy's post-model calculation considers avoidance specifically 
(i.e., assuming animals present beyond the range of PTS for the first 
few pings will be able to avoid it and incur only TTS, which results in 
a 95 percent reduction in the number of estimated PTS takes predicted 
by the model), given that sound sources are moving, it may not be until 
later in an exercise that the animal is close enough to experience PTS, 
and it is those few close pings that contribute to the potential to 
experience PTS. An animal being beyond the PTS zone initially has no 
bearing on whether it will come within close range later during an 
exercise since both sources and animals are moving. In addition, Navy 
vessels may move faster than the ability of the animals to evacuate the 
area. The Navy should have been able to query the dosimeters of the 
animats to verify whether its 5-percent assumption was valid. 
Commenters are concerned that this method underestimates the number of 
PTS takes.
    Response: The consideration of marine mammals avoiding the area 
immediately around the sound source is provided in the Navy's 2018 
technical report titled Quantitative Analysis for Estimating Acoustic 
and Explosive Impacts to Marine Mammals and Sea Turtles. As the 
commenter correctly articulates: ``For avoidance, the Navy assumed that 
animals present beyond the range to onset PTS for the first three to 
four pings are assumed to avoid any additional exposures at levels that 
could cause PTS. That equated to approximately 5 percent of the total 
pings or 5 percent of the overall time active; therefore, 95 percent of 
marine mammals predicted to experience PTS due to sonar and other 
transducers were instead assumed to experience TTS.'' In regard to the 
comment about vessels moving faster than animals' ability to get out of 
the way, as discussed in the Navy's 2018 technical report titled 
Quantitative Analysis for Estimating Acoustic and Explosive Impacts to 
Marine Mammals and Sea Turtles, animats in the Navy's acoustic effects 
model do not move horizontally or ``react'' to sound in any way, 
necessitating the additional step of considering animal avoidance of 
close-in PTS zones. NMFS independently reviewed this approach and 
concurs that it is fully supported by the best available science. Based 
on a growing body of behavioral response research, animals do in fact 
avoid the immediate area around sound sources to a distance of a few 
hundred meters or more depending upon the species. Avoidance to this 
distance greatly reduces the likelihood of impacts to hearing such as 
TTS and PTS, respectively. Specifically, the ranges to PTS for most 
marine mammal groups are within a few tens of meters and the ranges for 
the most sensitive group, the HF cetaceans, average about 200 m, to a 
maximum of 270 m in limited cases. Querying the dosimeters of the 
animats would not produce useful information since, as discussed 
previously, the animats do not move in the horizontal and are not 
programmed to ``react'' to sound or any other stimulus. The commenter 
references comments that they have previously submitted on the Navy's 
Gulf of Alaska incidental take regulations and we refer the commenter 
to NMFS' responses, which were included in the Federal Register 
document announcing the issuance of the final regulations (82 FR 19572, 
April 27, 2017).
Underestimated Beaked Whale Injury and Mortality
    Comment 17: A commenter commented that the Navy and NMFS both 
underestimate take for Cuvier's beaked whales because they are 
extremely sensitive to sonar. A new study of Cuvier's beaked whales in 
Southern California exposed to mid and high-power sonar confirmed that 
they modify their diving behavior up to 100-km away (Falcone et al., 
2017). The commenter asserted that this science disproves NMFS' 
assumption that beaked whales will find suitable habitat nearby within 
their small range. This modified diving behavior, which was 
particularly strong when exposed to mid-power sonar, indicates 
disruption of feeding. Accordingly, impacts on Cuvier's beaked whales 
could include interference with essential behaviors that will have more 
than a negligible impact on this species. In addition, Lookouts and 
shutdowns do not protect Cuvier's beaked whales from Navy sonar because 
this is a deep-diving species that is difficult to see from ships.
    Response: Takes of Cuvier's beaked whales are not underestimated. 
The behavioral harassment threshold for beaked whales has two 
components, both of which consider the sensitivity of beaked whales. 
First, the biphasic behavioral harassment function for beaked whales, 
which is based on data on beaked whale responses, has a significantly 
lower mid-point than other groups and also reflects a significantly 
higher probability of ``take'' at lower levels (e.g., close to 15 
percent at 120 dB). Additionally, the distance cut-off used for beaked 
whales is farther than for any other group (50 km, for both the MF1 and 
MF4 bins, acknowledging the fact that the unpredictability of dipping 
sonar likely results in takes at greater distances than other more 
predictable sources of similar levels). Regarding the referenced 
article, the commenter is selectively citing only part of it. The 
study, which compiles information from multiple studies, found that 
shallow dives were predicted to increase in duration as the distance to 
both high-and mid-power MFAS sources decreased, beginning at 
approximately 100 km away and, specifically, the differences only 
varied from approximately 20 minutes without MFAS to about 24 minutes 
with MFAS at the closest distance (i.e., the dive time varied from 20 
to 24 minutes over the distance of 100 km away to the closest distance 
measured). Further, the same article predicted that deep dive duration 
(which is more directly associated with feeding and linked to potential 
energetic effects) was predicted to increase with proximity to mid-
power MFAS from approximately 60 minutes to approximately 90 minutes 
beginning at around 40 km (10 dives). There were four deep dives 
exposed high-power MFAS within 20 km, the distance at which deep dive 
durations increased with the lower power source types. Other responses 
to MFAS included deep dives that were shorter than typical and 
shallower, and instances where there were no observed responses at 
closer distances. The threshold for Level B harassment is higher than 
just ``any measurable response'' and NMFS and the Navy worked closely 
together to identify behavioral response functions and distance cut-
offs that reflect the best available science to identify when

[[Page 66882]]

marine mammal behavioral patterns will be disrupted to a point where 
they are abandoned or significantly altered. Further, the take estimate 
is in no way based on an assumption that beaked whales will always be 
sighted by Lookouts--and adjustment to account for Lookout 
effectiveness considers the variable detectability of different stocks. 
In this rule, both the take estimate and the negligible impact analysis 
appropriately consider the sensitivity of, and scale of impacts to (we 
address impacts to feeding and energetics), Cuvier's (and all) beaked 
whales.
    Comment 18: A commenter commented that NMFS is underestimating 
serious injury and mortality for beaked whales. A commenter noted the 
statement in the proposed rule that because a causal relationship 
between Navy MFAS use and beaked whale strandings has not been 
established in all instances, and that, in some cases, sonar was 
considered to be only one of several factors that, in aggregate, may 
have contributed to the stranding event, NMFS does ``not expect 
strandings, serious injury, or mortality of beaked whales to occur as a 
result of training activities.'' (83 FR at 30007). The commenter 
asserted that this opinion is inconsistent with best available science 
and does not take into account the fact that the leading explanation 
for the mechanism of sonar-related injuries--that whales suffer from 
bubble growth in organs that is similar to decompression sickness, or 
``the bends'' in human divers--has now been supported by numerous 
papers. At the same time, the commenter argued that NMFS fails to 
seriously acknowledge that sonar can seriously injure or kill marine 
mammals at distances well beyond those established for permanent 
hearing loss (83 FR 29916) and dismisses the risk of stranding and 
other mortality events (83 FR 30007) based on the argument that such 
effects can transpire only under the same set of circumstances that 
occurred during known sonar-related events--an assumption that is 
arbitrary and capricious. In conclusion, a commenter argued that none 
of NMFS' assumptions regarding the expected lack of serious injury and 
mortality for beaked whales are supported by the record, and all lead 
to an underestimation of impacts.
    Response: A commenter's characterization of NMFS' analysis is 
incorrect. NMFS does not disregard the fact that it is possible for 
naval activities using hull-mounted tactical sonar to contribute to the 
death of marine mammals in certain circumstances (that are not present 
in the HSTT Study Area) via strandings resulting from behaviorally 
mediated physiological impacts or other gas-related injuries. NMFS 
discussed these potential causes and outlined the few cases where 
active naval sonar (in the United States or, largely, elsewhere) had 
either potentially contributed to or (as with the Bahamas example) been 
more definitively causally linked with marine mammal strandings in the 
proposed rule. As noted, there are a suite of factors that have been 
associated with these specific cases of strandings directly associated 
with sonar (steep bathymetry, multiple hull-mounted platforms using 
sonar simultaneously, constricted channels, strong surface ducts, etc.) 
that are not present together in the HSTT Study Area and during the 
specified activities (and which the Navy takes care across the world 
not to operate under without additional monitoring). There have been no 
documented beaked whale mortalities from Navy activities within the 
HSTT Study Area. Further, none of the beaked whale strandings causally 
associated with Navy sonar stranding are in the Pacific. For these 
reasons, NMFS does not anticipate that the Navy's HSTT training or 
testing activities will result in beaked whale marine mammal 
strandings, and none are authorized. Furthermore, ongoing Navy funded 
beaked whale monitoring at a heavily used training and testing area in 
SOCAL has not documented mortality or habitat abandonment by beaked 
whales. Passive acoustic detections of beaked whales have not 
significantly changed over eight years of monitoring (DiMarzio et al., 
2018). From visual surveys in the area since 2006 there have been 
repeated sightings of: the same individual beaked whale, beaked whale 
mother-calf pairs, and beaked whale mother-calf pairs with mothers on 
their second calf (Schorr et al., 2018). Satellite tracking studies of 
beaked whale documented high site fidelity to this area even though the 
study area is located in one of the most used Navy areas in the Pacific 
(Schorr et al., 2018).
Ship Strike
    Comment 19: A commenter commented that the Navy's current approach 
to determine the risk of a direct vessel collision with marine mammals 
is flawed and fails to account for the likelihood that ship strikes 
since 2009 were unintentionally underreported. The commenters noted 
that vessel collisions are generally underreported in part because they 
can be difficult to detect, especially for large vessels and that the 
distribution, being based on reported strikes, does not account for 
this problem. Additionally, the commenter asserted that the Navy's 
analysis does not address the potential for increased strike risk of 
non-Navy vessels as a consequence of acoustic disturbance. For example, 
some types of anthropogenic noise have been shown to induce near-
surfacing behavior in right whales, increasing the risk of ship-
strike--by not only the source vessel but potentially by third-party 
vessels in the area--at relatively moderate levels of exposure (Nowacek 
et al., 2004). An analysis based on reported strikes by Navy vessels 
per se does not account for this additional risk. In assessing ship-
strike risk, the Navy should include offsets to account for potentially 
undetected and unreported collisions.
    Response: While NMFS agrees that broadly speaking the number of 
total ship strikes may be underestimated due to incomplete information 
from other sectors (shipping, etc.), NMFS is confident that whales 
struck by Navy vessels are detected and reported, and Navy strikes are 
the numbers used in NMFS' analysis to support the authorized number of 
strikes. Navy ships have multiple Lookouts, including on the forward 
part of the ship that can visually detect a hit whale (which has 
occasionally occurred), in the unlikely event ship personnel do not 
feel the strike. The Navy's strict internal procedures and mitigation 
requirements include reporting of any vessel strikes of marine mammals, 
and the Navy's discipline, extensive training (not only for detecting 
marine mammals, but for detecting and reporting any potential 
navigational obstruction), and strict chain of command give NMFS a high 
level of confidence that all strikes actually get reported. 
Accordingly, NMFS is confident that the information used to support the 
analysis is accurate and complete.
    There is no evidence that Navy training and testing activities (or 
other acoustic activities) increase the risk of nearby non-Navy vessels 
(or other nearby Navy vessels not involved in the referenced training 
or testing) striking marine mammals. More whales are struck by non-Navy 
vessels off California in areas outside of the HSTT Study Area such as 
approaches to Los Angeles and San Francisco.

Mitigation and Monitoring

Least Practicable Adverse Impact Determination
    Comment 20: A commenter commented that deaths of, or serious 
injuries to marine mammals that occur pursuant to activities conducted 
under an incidental take authorization, while

[[Page 66883]]

perhaps negligible to the overall health and productivity of the 
species or stock and of little consequence at that level, nevertheless 
are clearly adverse to the individuals involved and results in some 
quantifiable (though negligible) adverse impact on the population; it 
reduces the population to some degree. Under the least practicable 
adverse impact requirement, and more generally under the purposes and 
policies of the MMPA, the commenter asserted that Congress embraced a 
policy to minimize, whenever practicable, the risk of killing or 
seriously injuring a marine mammal incidental to an activity subject to 
section 101(a)(5)(A), including providing measures in an authorization 
to eliminate or reduce the likelihood of lethal taking. The commenter 
recommended that NMFS address this point explicitly in its analysis and 
clarify whether it agrees that the incidental serious injury or death 
of a marine mammal always should be considered an adverse impact for 
purposes of applying the least practicable adverse impact standard.
    Response: NMFS disagrees that it is necessary or helpful to 
explicitly address the point the commenter raises in the general 
description of the least practicable adverse impact standard. The 
discussion of this standard already notes that there can be population-
level impacts that fall below the ``negligible'' standard, but that are 
still appropriate to mitigate under the least practicable adverse 
impact standard. It is always NMFS' practice to mitigate mortality to 
the greatest degree possible, as death is the impact that is most 
easily linked to reducing the probability of adverse impacts to 
populations. However, we cannot agree that one mortality will always 
decrease any population in a quantifiable or meaningful way. For 
example, for very large populations, one mortality may fall well within 
typical known annual variation and not have any effect on population 
rates. Further, we do not understand the problem that the commenter's 
recommendation is attempting to fix. Applicants generally do not 
express reluctance to mitigate mortality, and we believe that 
modifications of this nature would confuse the issue.
    Comment 21: A commenter recommended that NMFS address the habitat 
component of the least practicable adverse impact provision in greater 
detail. It asserted that NMFS' discussion of critical habitat, marine 
sanctuaries, and BIAs in the proposed rule is not integrated with the 
discussion of the least practicable adverse impact standard. It would 
seem that, under the least practicable adverse impact provision, 
adverse impacts on important habitat should be avoided whenever 
practicable. Therefore, to the extent that activities would be allowed 
to proceed in these areas, NMFS should explain why it is not 
practicable to constrain them further.
    Response: Marine mammal habitat value is informed by marine mammal 
presence and use and, in some cases, there may be overlap in measures 
for the species or stock directly and for use of habitat. In this rule, 
we have identified time-area mitigations based on a combination of 
factors that include higher densities and observations of specific 
important behaviors of marine mammals themselves, but also that clearly 
reflect preferred habitat (e.g., calving areas in Hawaii, feeding areas 
SOCAL). In addition to being delineated based on physical features that 
drive habitat function (e.g., bathymetric features, among others for 
some BIAs), the high densities and concentration of certain important 
behaviors (e.g., feeding) in these particular areas clearly indicate 
the presence of preferred habitat. The commenter seems to suggest that 
NMFS must always consider separate measures aimed at marine mammal 
habitat; however, the MMPA does not specify that effects to habitat 
must be mitigated in separate measures, and NMFS has clearly identified 
measures that provide significant reduction of impacts to both ``marine 
mammal species and stocks and their habitat,'' as required by the 
statute.
    Comment 22: A commenter recommended that NMFS rework its evaluation 
criteria for applying the least practicable adverse impact standard to 
separate the factors used to determine whether a potential impact on 
marine mammals or their habitat is adverse and whether possible 
mitigation measures would be effective. In this regard, the commenter 
asserted that it seems as though the proposed ``effectiveness'' 
criterion more appropriately fits as an element of practicability and 
should be addressed under that prong of the analysis. In other words, a 
measure not expected to be effective should not be considered a 
practicable means of reducing impacts.
    Response: In the Mitigation Measures section, NMFS has explained in 
detail our interpretation of the least practicable adverse impact 
standard, the rationale for our interpretation, and our approach for 
implementing our interpretation. The ability of a measure to reduce 
effects on marine mammals is entirely related to its ``effectiveness'' 
as a measure, whereas the effectiveness of a measure is not connected 
to its practicability. The commenter provides no support for its 
argument, and NMFS has not implemented the Commission's suggestion.
    Comment 23: A commenter recommended that NMFS recast its 
conclusions to provide sufficient detail as to why additional measures 
either are not needed (i.e., there are no remaining adverse impacts) or 
would not be practicable to implement. The commenter states that the 
most concerning element of NMFS' implementation of the least 
practicable adverse impact standard is its suggestion that the 
mitigation measures proposed by the Navy will ``sufficiently reduce 
impacts on the affected mammal species and stocks and their habitats'' 
(83 FR 11045). That phrase suggests that NMFS is applying a ``good-
enough'' standard to the Navy's activities. Under the statutory 
criteria, however, those proposed measures are ``sufficient'' only if 
they have either (1) eliminated all adverse impacts on marine mammal 
species and stocks and their habitat or (2) if adverse impacts remain, 
it is impracticable to reduce them further.
    Response: The statement that the commenter references does not 
indicate that NMFS applies a ``good-enough'' standard to determining 
least practicable adverse impact. Rather, it indicates that the 
mitigation measures are sufficient to meet the statutory legal 
standard. In addition, as NMFS has explained in our description of the 
least practicable adverse impact standard, NMFS does not view the 
necessary analysis through the yes/no lens that the commenter seeks to 
prescribe. Rather, NMFS' least practicable adverse impact analysis 
considers both the reduction of adverse effects and their 
practicability. Further, since the proposed rule was published, the 
Navy and NMFS have evaluated additional measures in the context of both 
their practicability and their ability to further reduce impacts to 
marine mammals and have determined that the addition of several 
measures (see Mitigation Measures) is appropriate. Regardless, beyond 
these new additional measures, where the Navy's HSTT activities are 
concerned, the Navy has indicated that further procedural or area 
mitigation of any kind (beyond that prescribed in this final rule) 
would be entirely impracticable. NMFS has reviewed documentation and 
analysis provided by the Navy explaining how and why specific 
procedural and geographic based mitigation measures impact 
practicability, and NMFS concurs with these assessments and has 
determined that the mitigation measures outlined in the final rule 
satisfy the statutory standard and that any adverse

[[Page 66884]]

impacts that remain are unable to be further mitigated.
    Comment 24: A commenter recommended that any ``formal 
interpretation'' of the least practicable adverse impact standard by 
NMFS be issued in a stand-alone, generally applicable rulemaking (e.g., 
in amendments to 50 CFR 216.103 or 216.105) or in a separate policy 
directive, rather than in the preambles to individual proposed rules.
    Response: We appreciate the commenter's recommendation and may 
consider the recommended approaches in the future. We note, however, 
that providing relevant explanations in a proposed incidental take rule 
is an effective and efficient way to provide information to the reader 
and solicit focused input from the public, and ultimately affords the 
same opportunities for public comment as a stand-alone rulemaking 
would. NMFS has provided similar explanations of the least practicable 
adverse impact standard in other recent section 101(a)(5)(A) rules, 
including: U.S. Navy Operations of Surveillance Towed Array Sensor 
System Low Frequency Active (SURTASS LFA) Sonar; Geophysical Surveys 
Related to Oil and Gas Activities in the Gulf of Mexico; and the final 
rule for U.S. Navy Training and Testing Activities in the Atlantic 
Fleet Study Area.
    Comment 25: A commenter cited two judicial decisions and commented 
that the ``least practicable adverse impact'' standard has not been 
met. A commenter stated that contrary to the Pritzker Court decision, 
NMFS, while clarifying that population-level impacts are mitigated 
``through the application of mitigation measures that limit impacts to 
individual animals,'' has again set population-level impact as the 
basis for mitigation in the proposed rule. Because NMFS' mitigation 
analysis is opaque, it is not clear what practical effect this position 
may have on its rulemaking. A commenter stated that the proposed rule 
is also unclear in its application of the ``habitat'' emphasis in the 
MMPA's mitigation standard, and that while NMFS' analysis is opaque, 
its failure to incorporate or even, apparently, to consider viable 
time-area measures suggests that the agency has not addressed this 
aspect of the Pritzker decision. A commenter argues that the MMPA sets 
forth a ``stringent standard'' for mitigation that requires the agency 
to minimize impacts to the lowest practicable level, and that the 
agency must conduct its own analysis and clearly articulate it: it 
``cannot just parrot what the Navy says.''
    Response: NMFS disagrees with much of what a commenter asserts. 
When a suggested or recommended mitigation measure is impracticable, 
NMFS has explored variations of that mitigation to determine if a 
practicable form of related mitigation exists. This is clearly 
illustrated in NMFS' independent mitigation analysis process explained 
in this rule. First, the type of mitigation required varies by 
mitigation area, demonstrating that NMFS has engaged in a site-specific 
analysis to ensure mitigation is tailored when practicability demands, 
i.e., some forms of mitigation were practicable in some areas but not 
others. Examples of NMFS' analysis on this issue appear throughout the 
rule. For instance, while it was not practicable for the Navy to 
include a mitigation area for the Tanner-Cortes blue whale BIA, the 
Navy did agree to expand mitigation protection to all of the other blue 
whale BIAs in the SOCAL region. Additionally, while the Navy cannot 
alleviate all training in the mitigation areas that protect small 
resident odontocete populations in Hawaii, has further expanded the 
protections in those areas such that it does not use explosives or MFAS 
in the areas (MF1 bin in both areas, MF4 bin in the Hawaii Island 
area). Nonetheless, NMFS agrees that the agency must conduct its own 
analysis, which it has done here, and not just accept what is provided 
by the Navy. That does not mean, however, that NMFS cannot review the 
Navy's analysis of effectiveness and practicability, and concur with 
those aspects of the Navy's analysis with which NMFS agrees. A 
commenter seems to suggest that NMFS must describe in the rule in 
detail the rationale for not adopting every conceivable permutation of 
mitigation, which is neither reasonable nor required by the MMPA. NMFS 
has described our well-reasoned process for identifying the measures 
needed to meet the least practicable adverse impact standard in the 
Mitigation Measures section in this rule, and we have followed the 
approach described there when analyzing potential mitigation for the 
Navy's activities in the HSTT Study Area. Discussion regarding specific 
recommendations for mitigation measures provided by a commenter on the 
proposed rule are discussed separately.
Procedural Mitigation Effectiveness and Recommendations
    Comment 26: A commenter commented that the Navy's proposed 
mitigation zones are similar to the zones previously used during Phase 
II activities and are intended, based on the Phase III HSTT DEIS/OEIS, 
to avoid the potential for marine mammals to be exposed to levels of 
sound that could result in injury (i.e., PTS). However, the commenter 
believed that Phase III proposed mitigation zones would not protect 
various functional hearing groups from PTS. For example, the mitigation 
zone for an explosive sonobuoy is 549 m but the mean PTS zones range 
from 2,113-3,682 m for HF. Similarly, the mitigation zone for an 
explosive torpedo is 1,920 m but the mean PTS zones range from 7,635-
10,062 m for HF, 1,969-4,315 m for LF, and 3,053-3,311 for PW. The 
appropriateness of such zones is further complicated by platforms 
firing munitions (e.g., for missiles and rockets) at targets that are 
28 to 139 km away from the firing platform. An aircraft would clear the 
target area well before it positions itself at the launch location and 
launches the missile or rocket. Ships, on the other hand, do not clear 
the target area before launching the missile or rocket. In either case, 
marine mammals could be present in the target area unbeknownst to the 
Navy at the time of the launch.
    Response: NMFS is aware that some mitigation zones do not fully 
cover the area in which an animal from a certain hearing group may 
incur PTS. For this small subset of circumstances, NMFS discussed 
potential enlargement of the mitigation zones with the Navy, but 
concurred with the Navy's assessment that further enlargement would be 
impracticable. Specifically, the Navy explained that explosive 
mitigation zones, as discussed in Chapter 5 (Mitigation) of the HSTT 
FEIS/OEIS, any additional increases in mitigation zone size (beyond 
what is depicted for each explosive activity), or additional 
observation requirements would be impracticable to implement due to 
implications for safety, sustainability, the Navy's ability to meet 
Title 10 requirements to successfully accomplish military readiness 
objectives, and the Navy's ability to conduct testing associated with 
required acquisition milestones or as required on an as-needed basis to 
meet operational requirements. Additionally, Navy Senior Leadership has 
approved and determined that the mitigation detailed in Chapter 5 
(Mitigation) of the HSTT FEIS/OEIS provides the greatest extent of 
protection that is practicable to implement. The absence of mitigation 
to avoid all Level A harassment in some of these circumstances has been 
analyzed, however, and the Navy is authorized for any of these Level A 
harassment takes that may occur.

[[Page 66885]]

    Comment 27: One commenter made several comments regarding visual 
and acoustic detection as related to mitigating impacts that can cause 
injury. The commenter noted that the Navy indicated in the HSTT DEIS/
OEIS that Lookouts would not be 100 percent effective at detecting all 
species of marine mammals for every activity because of the inherent 
limitations of observing marine species and because the likelihood of 
sighting individual animals is largely dependent on observation 
conditions (e.g., time of day, sea state, mitigation zone size, 
observation platform). The Navy has been collaborating with researchers 
at the University of St. Andrews to study Navy Lookout effectiveness 
and the commenter anticipates that the Lookout effectiveness study will 
be very informative once completed, but notes that in the interim, the 
preliminary data do provide an adequate basis for taking a 
precautionary approach. The commenter believed that rather than simply 
reducing the size of the mitigation zones it plans to monitor, the Navy 
should supplement its visual monitoring efforts with other monitoring 
measures including passive acoustic monitoring.
    The commenter suggested that sonobuoys could be deployed with the 
target in the various target areas prior to the activity. This approach 
would allow the Navy to better determine whether the target area is 
clear and remains clear until the munition is launched.
    Although the Navy indicated that it was continuing to improve its 
capabilities for using range instrumentation to aid in the passive 
acoustic detection of marine mammals, it also stated that it didn't 
have the capability or resources to monitor instrumented ranges in real 
time for the purpose of mitigation. That capability clearly exists. 
While available resources could be a limiting factor, the commenter 
notes that personnel who monitor the hydrophones on the operational 
side do have the ability to monitor for marine mammals as well. The 
commenter has supported the use of the instrumented ranges to fulfill 
mitigation implementation for quite some time (see the commenter's most 
recent November 13, 2017 letter) and contends that localizing certain 
species (or genera) provides more effective mitigation than localizing 
none at all.
    The commenter recommended that NMFS require the Navy to use passive 
and active acoustic monitoring, whenever practicable, to supplement 
visual monitoring during the implementation of its mitigation measures 
for all activities that have the potential to cause injury or mortality 
beyond those explosive activities for which passive acoustic monitoring 
already was proposed, including those activities that would occur on 
the SCORE and PMRF ranges.
    Response: For explosive mitigation zones, any additional increases 
in mitigation zone size (beyond what is depicted for each explosive 
activity) or observation requirements would be impracticable to 
implement due to implications for safety, sustainability, and the 
Navy's ability to meet Title 10 requirements to successfully accomplish 
military readiness objectives. We do note, however, that since the 
proposed rule, the Navy has committed to implementing pre-event 
observations for all in-water explosives events (including some that 
were not previously monitored) and to using additional platforms if 
available in the vicinity of the detonation area to help with this 
monitoring.
    As discussed in the comment, the Navy does employ passive acoustic 
monitoring when practicable to do so (i.e., when assets that have 
passive acoustic monitoring capabilities are already participating in 
the activity). For other explosive events, there are no platforms 
participating that have passive acoustic monitoring capabilities. 
Adding a passive acoustic monitoring capability (either by adding a 
passive acoustic monitoring device to a platform already participating 
in the activity, or by adding a platform with integrated passive 
acoustic monitoring capabilities to the activity, such as a sonobuoy) 
for mitigation is not practicable. As discussed in Section 5.5.3 
(Active and Passive Acoustic Monitoring Devices) of the HSTT FEIS/OEIS, 
there are significant manpower and logistical constraints that make 
constructing and maintaining additional passive acoustic monitoring 
systems or platforms for each training and testing activity 
impracticable. Additionally, diverting platforms that have passive 
acoustic monitoring platforms would impact their ability to meet their 
Title 10 requirements and reduce the service life of those systems.
    Regarding the use of instrumented ranges for realtime mitigation, 
the commenter is correct that the Navy continues to develop the 
technology and capabilities on its Ranges for use in marine mammal 
monitoring, which can be effectively compared to operational 
information after the fact to gain information regarding marine mammal 
response. However, as discussed above, the manpower and logistical 
complexity involved in detecting and localizing marine mammals in 
relation to multiple fast-moving sound source platforms in order to 
implement real-time mitigation is significant. A more detailed 
discussion of the limitations for on range passive acoustic detection 
as real-time mitigation is provided in Comment 34 and is impracticable 
for the Navy. The Navy's instrumented ranges were not developed for the 
purpose of mitigation. For example, beaked whales produce highly 
directed echolocation clicks that are difficult to simultaneously 
detect on multiple hydrophones within the instrumented range at PMRF; 
therefore, there is a high probability that a vocalizing animal would 
be assigned a false location on the range (i.e., the Navy would not be 
able to verify its presence in a mitigation zone). Although the Navy is 
continuing to improve its capabilities to use range instrumentation to 
aid in the passive acoustic detection of marine mammals, at this time 
it would not be effective or practicable for the Navy to monitor 
instrumented ranges for the purpose of real-time mitigation for the 
reasons discussed in Section 5.5.3 (Active and Passive Acoustic 
Monitoring Devices) of the HSTT FEIS/OEIS.
    Comment 28: The commenter recommended that NMFS require the Navy to 
conduct additional pre-activity overflights before conducting any 
activities involving detonations barring any safety issues (e.g., low 
fuel), as well as post-activity monitoring for activities involving 
medium- and large caliber projectiles, missiles, rockets, and bombs.
    Response: The Navy has agreed to implement pre-event observation 
mitigation, as well as post-event observation, for all in-water 
explosive event mitigation measures. If there are other platforms 
participating in these events and in the vicinity of the detonation 
area, they will also visually observe this area as part of the 
mitigation team.
    Comment 29: One commenter recommended that the Navy implement 
larger shutdown zones.
    Response: The Navy mitigation zones represent the maximum surface 
area the Navy can effectively observe based on the platform involved, 
number of personnel that will be involved, and the number and type of 
assets and resources available. As mitigation zone sizes increase, the 
potential for observing marine mammals and thus reducing impacts 
decreases, because the number of observers can't increase although the 
area to observe increases. For instance, if a mitigation zone increases 
from 1,000 to 2,000 yd., the area that must be observed increases five-
fold. NMFS has

[[Page 66886]]

analyzed the Navy's required mitigation and found that it will effect 
the least practicable adverse impact. The Navy's mitigation measures 
consider both the need to reduce potential impacts and the ability to 
provide effective observations throughout a given mitigation zone. To 
implement these mitigation zones, Navy Lookouts are trained to use a 
combination of unaided eye and optics as they search the surface around 
a vessel. In addition, there are other Navy personnel on a given bridge 
watch (in addition to designated Lookouts), who are also constantly 
watching the water for safety of navigation and marine mammals. Takes 
that cannot be mitigated are analyzed and authorized provided the 
necessary findings can be made.
    Comment 30: Commenters commented that NMFS should cap the maximum 
level of activities each year.
    Response: The commenters offers no rationale for why a cap is 
needed and nor do they suggest what an appropriate cap might be. The 
Navy is responsible under Title 10 for conducting the needed amount of 
testing and training to maintain military readiness, which is what they 
have proposed and NMFS has analyzed. Further, the MMPA states that NMFS 
shall issue MMPA authorizations if the necessary findings can be made, 
as they have been here. Importantly, as described in the Mitigation 
Areas section, the Navy will limit activities (active sonar, explosive 
use, MTE exercises, etc.) to varying degrees in multiple areas that are 
important to sensitive species or for critical behaviors in order to 
minimize impacts that are more likely to lead to adverse effects on 
rates of recruitment or survival.
    Comment 31: A commenter suggested the Navy could improve observer 
effectiveness through the use of NMFS-certified marine mammal 
observers.
    Response: The Navy currently requires at least one qualified 
Lookout on watch at all times a vessel is underway. In addition, on 
surface ships with hull-mounted sonars during sonar events, the number 
increases with two additional Lookouts on the forward portion of the 
vessel (i.e., total of three Lookouts). Furthermore, unlike civilian 
commercial ships, there are additional bridge watch standers on Navy 
ships viewing the water during all activities. The Navy's Marine 
Species Awareness training that all bridge watchstanders including 
Lookouts take has been reviewed and approved by NMFS. This training is 
conducted annually and prior to MTEs. Note, Navy visual monitoring from 
Lookouts and bridge watchstanders as well as unit-based passive 
acoustic detection is used when available and appropriate.
    As we understand from the Navy, mandating NMFS-certified marine 
mammal observers on all ships would require setting up and 
administering a certification program, providing security clearance for 
certified people, ensuring that all platforms are furnished with these 
individuals, and housing these people on ships for extended times from 
weeks to months. This would be an extreme logistic burden on realistic 
training. The requirement for additional non-Navy observers would 
provide little additional benefit, especially at the near ship 
mitigation ranges for mid-frequency active sonars on surface ships 
(<1,000 yds), nor be significantly better than the current system 
developed by the Navy in consultation with NMFS.
    The purpose of Navy Lookouts is to provide sighting information for 
other boats and vessels in the area, in-water debris, and other safety 
of navigation functions. During active sonar use, additional personnel 
are assigned for the duration of the sonar event. In addition, the 
other Navy personnel on a given bridge watch along with designated 
Lookouts are also constantly watching the water for safety of 
navigation and marine mammals.
    Navy training and testing activities often occur simultaneously and 
in various regions throughout the HSTT Study Area, with underway time 
that could last for days or multiple weeks at a time. The pool of 
certified marine mammal observers across the U.S. West Coast is rather 
limited, with many already engaged in regional NMFS survey efforts. 
Relative to the number of dedicated MMOs that would be required to 
implement this condition, as of July 2018, there are approximately 22 
sonar-equipped Navy ships (i.e., surface ships with hull-mounted active 
sonars) stationed in San Diego. Six additional vessels from the Pacific 
Northwest also transit to Southern California for training (28 ships 
times 2 observers per watch times 2 watches per day = minimum of 112 
observers).
    Senior Navy commands in the Pacific continuously reemphasize the 
importance of Lookout responsibilities to all ships. Further, the Navy 
has an ongoing study in which certified Navy civilian scientist 
observers embark periodically on Navy ships in support of a comparative 
Lookout effectiveness study. Results from this study will be used to 
make recommendations for further improvements to Lookout training.
    Additionally, we note that the necessity to include trained NMFS-
approved PSOs on Navy vessels, while adding little or no additional 
protective or data-gathering value, would be very expensive and those 
costs would need to be offset--most likely through reductions in the 
budget for Navy monitoring, through which invaluable data is gathered.
    Comment 32: Commenters commented that NMFS should consider 
increasing the exclusion zone to the 120 dB isopleth because some 
animals are sensitive to sonar at low levels of exposure.
    Response: First, it is important to note that the Commenters are 
suggesting that NMFS require mitigation that would eliminate all take, 
which is not what the applicable standard requires. Rather, NMFS is 
required to put in place measures that effect the ``least practicable 
adverse impact.'' Separately, NMFS acknowledges that some marine 
mammals may respond to sound at 120 dB in some circumstances; however, 
based on the best available data, only a subset of those exposed at 
that low level respond in a manner that would be considered harassment 
under the MMPA. NMFS and the Navy have quantified those individuals of 
certain stocks where appropriate, analyzed the impacts, and authorized 
them where needed. Further, NMFS and the Navy have identified exclusion 
zone sizes that are best suited to minimize impacts to marine mammal 
species and stocks and their habitat while also being practicable (see 
Mitigation section).
    Comment 33: A commenter commented that NMFS should impose a 10-kn 
ship speed in biologically important areas and critical habitat for 
marine mammals to reduce vessel strikes. One commenter also 
specifically referenced this measure in regard to humpback whales and 
blue whales.
    Response: This issue also is addressed elsewhere in the Comments 
and Responses section for specific mitigation areas. However, generally 
speaking, it is impracticable (because of impacts to mission 
effectiveness) to further reduce ship speeds for Navy activities, and, 
moreover, given the maneuverability of Navy ships at higher speeds and 
the presence of effective Lookouts, any further reduction in speed 
would reduce the already low probability of ship strike little, if any. 
The Navy is unable to impose a 10-kn ship speed limit because it would 
not be practical to implement and would impact the effectiveness of 
Navy's activities by putting constraints on training, testing, and 
scheduling. The Navy requires flexibility in use of variable ship 
speeds for training, testing, operational, safety, and engineering 
qualification requirements. Navy ships

[[Page 66887]]

typically use the lowest speed practical given individual mission 
needs. NMFS has reviewed the Navy's analysis of these additional 
restrictions and the impacts they would have on military readiness and 
concurs with the Navy's assessment that they are impracticable.
    The main driver for ship speed reduction is reducing the 
possibility and severity of ship strikes to large whales. However, even 
given the wide ranges of speeds from slow to fast that Navy ships must 
use to meet training and testing requirements, the Navy has a very low 
strike history to large whales in Southern California, with no whales 
struck by the Navy from 2010-2018. Current Navy Standard Operating 
Procedures and mitigations require a minimum of at least one Lookout on 
duty while underway (in addition to bridge watch personnel) and, so 
long as safety of navigation is maintained, to keep 500 yards away from 
large whales and 200 yards away from other marine mammals (except for 
bow-riding dolphins and pinnipeds hauled out on shore or structures). 
Furthermore, there is no Navy ship strike of a marine mammal on record 
in SOCAL that has occurred in the coastal area (~40 Nmi from shore), 
which is where speed restrictions are most requested. Finally, the most 
recent model estimate of the potential for civilian ship strike risk to 
blue, humpback, and fin whales off the coast of California found the 
highest risk near San Francisco and Long Beach associated with 
commercial ship routes to and from those ports (Rockwood et al., 2018). 
There was no indication of a similar high risk to these species off San 
Diego, where the HSTT Study Area occurs.
    Previously, the Navy commissioned a vessel density and speed report 
based on an analysis of Navy ship traffic in the HSTT Study Area 
between 2011 and 2015. Median speed of all Navy vessels within the HSTT 
Study Area is typically already low, with median speeds between 5 and 
12 knots. Further, the presence and transits of commercial and 
recreational vessels, annually numbering in the thousands, poses a more 
significant risk to large whales than the presence of Navy vessels. The 
HSTT FEIS/OEIS Chapter 3 (Affected Environment and Environmental 
Consequences) Section 3.7.3.4.1 (Impacts from Vessels and In-Water 
Devices) and Appendix K, Section K.4.1.6.2 (San Diego (Arc) Blue Whale 
Feeding Area Mitigation Considerations), explain the important 
differences between most Navy vessels and their operation and 
commercial ships that make Navy vessels much less likely to strike a 
whale.
    When developing Phase III mitigation measures, the Navy analyzed 
the potential for implementing additional types of mitigation, such as 
vessel speed restrictions within the HSTT Study Area. The Navy 
determined that based on how the training and testing activities will 
be conducted within the HSTT Study Area, vessel speed restrictions 
would be incompatible with practicability criteria for safety, 
sustainability, and training and testing missions, as described in 
Chapter 5 (Mitigation), Section 5.3.4.1 (Vessel Movement) of the HSTT 
FEIS/OEIS.
    Comment 34: Commenters commented that NMFS should improve detection 
of marine mammals with restrictions on low-visibility activities and 
alternative detection such as thermal or acoustic methods.
    Response: The Navy has compiled information related to the 
effectiveness of certain equipment to detect marine mammals in the 
context of their activities, as well as the practicality and effect on 
mission effectiveness of using various equipment. NMFS has reviewed 
this evaluation and concurs with the characterization and the 
conclusions below.
    Low visibility--Anti-submarine warfare training involving the use 
of mid-frequency active sonar typically involves the periodic use of 
active sonar to develop the ``tactical picture,'' or an understanding 
of the battle space (e.g., area searched or unsearched, presence of 
false contacts, and an understanding of the water conditions). 
Developing the tactical picture can take several hours or days, and 
typically occurs over vast waters with varying environmental and 
oceanographic conditions. Training during both high visibility (e.g., 
daylight, favorable weather conditions) and low visibility (e.g., 
nighttime, inclement weather conditions) is vital because sonar 
operators must be able to understand the environmental differences 
between day and night and varying weather conditions and how they 
affect sound propagation and the detection capabilities of sonar. 
Temperature layers move up and down in the water column and ambient 
noise levels can vary significantly between night and day, affecting 
sound propagation and how sonar systems are operated. Reducing or 
securing power in low-visibility conditions as a mitigation would 
affect a commander's ability to develop the tactical picture and would 
prevent sonar operators from training in realistic conditions. Further, 
during integrated training multiple vessels and aircraft may 
participate in an exercise using different dimensions of warfare 
simultaneously (e.g., submarine warfare, surface warfare, air warfare, 
etc.). If one of these training elements were adversely impacted (e.g., 
if sonar training reflecting military operations were not possible), 
the training value of other integrated elements would also be degraded. 
Additionally, failure to test such systems in realistic military 
operational scenarios increases the likelihood these systems could fail 
during military operations, thus unacceptably placing Sailors' lives 
and the Nation's security at risk. Some systems have a nighttime 
testing requirement; therefore, these tests cannot occur only in 
daylight hours. Reducing or securing power in low visibility conditions 
would decrease the Navy's ability to determine whether systems are 
operationally effective, suitable, survivable, and safe for their 
intended use by the fleet even in reduced visibility or difficult 
weather conditions.
    Thermal detection--Thermal detection systems are more useful for 
detecting marine mammals in some marine environments than others. 
Current technologies have limitations regarding water temperature and 
survey conditions (e.g., rain, fog, sea state, glare, ambient 
brightness), for which further effectiveness studies are required. 
Thermal detection systems are generally thought to be most effective in 
cold environments, which have a large temperature differential between 
an animal's temperature and the environment. Current thermal detection 
systems have proven more effective at detecting large whale blows than 
the bodies of small animals, particularly at a distance. The 
effectiveness of current technologies has not been demonstrated for 
small marine mammals. Thermal detection systems exhibit varying degrees 
of false positive detections (i.e., incorrect notifications) due in 
part to their low sensor resolution and reduced performance in certain 
environmental conditions. False positive detections may incorrectly 
identify other features (e.g., birds, waves, boats) as marine mammals. 
In one study, a false positive rate approaching one incorrect 
notification per 4 min. of observation was noted.
    The Navy has been investigating the use of thermal detection 
systems with automated marine mammal detection algorithms for future 
mitigation during training and testing, including on autonomous 
platforms. Thermal detection technology being researched by the Navy, 
which is largely based on existing foreign military grade hardware, is 
designed to allow observers and eventually automated software to detect 
the difference in temperature

[[Page 66888]]

between a surfaced marine mammal (i.e., the body or blow of a whale) 
and the environment (i.e., the water and air). Although thermal 
detection may be reliable in some applications and environments, the 
current technologies are limited by their: (1) Low sensor resolution 
and a narrow fields of view, (2) reduced performance in certain 
environmental conditions, (3) inability to detect certain animal 
characteristics and behaviors, and (4) high cost and uncertain long 
term reliability.
    Thermal detection systems for military applications are deployed on 
various Department of Defense (DoD) platforms. These systems were 
initially developed for night time targeting and object detection such 
as a boat, vehicle, or people. Existing specialized DoD infrared/
thermal capabilities on Navy aircraft and surface ships are designed 
for fine-scale targeting. Viewing arcs of these thermal systems are 
narrow and focused on a target area. Furthermore, sensors are typically 
used only in select training events, not optimized for marine mammal 
detection, and have a limited lifespan before requiring expensive 
replacement. Some sensor elements can cost upward of $300,000 to 
$500,000 per device, so their use is predicated on a distinct military 
need.
    One example of trying to use existing DoD thermal system is being 
proposed by the U.S. Air Force. The Air Force agreed to attempt to use 
specialized U.S. Air Force aircraft with military thermal detection 
systems for marine mammal detection and mitigation during a limited at-
sea testing event. It should be noted, however, these systems are 
specifically designed for and integrated into a small number of U.S. 
Air Force aircraft and cannot be added or effectively transferred 
universally to Navy aircraft. The effectiveness remains unknown in 
using a standard DoD thermal system for the detection of marine mammals 
without the addition of customized system-specific computer software to 
provide critical reliability (enhanced detection, cueing for an 
operator, reduced false positive, etc.)
    Finally, current DoD thermal sensors are not always optimized for 
marine mammal detections verse object detection, nor do these systems 
have the automated marine mammal detection algorithms the Navy is 
testing via its ongoing research program. The combination of thermal 
technology and automated algorithms are still undergoing demonstration 
and validation under Navy funding.
    Thermal detection systems specifically for marine mammal detection 
have not been sufficiently studied both in terms of their effectiveness 
within the environmental conditions found in the HSTT Study Area and 
their compatibility with Navy training and testing (i.e., polar waters 
vs. temperate waters). The effectiveness of even the most advanced 
thermal detection systems with technological designs specific to marine 
mammal surveys is highly dependent on environmental conditions, animal 
characteristics, and animal behaviors. At this time, thermal detection 
systems have not been proven to be more effective than, or equally 
effective as, traditional techniques currently employed by the Navy to 
observe for marine mammals (i.e., naked-eye scanning, hand-held 
binoculars, high-powered binoculars mounted on a ship deck). The use of 
thermal detection systems instead of traditional techniques would 
compromise the Navy's ability to observe for marine mammals within its 
mitigation zones in the range of environmental conditions found 
throughout the Study Area. Furthermore, thermal detection systems are 
designed to detect marine mammals and do not have the capability to 
detect other resources for which the Navy is required to implement 
mitigation, including sea turtles. Focusing on thermal detection 
systems could also provide a distraction from and compromise to the 
Navy's ability to implement its established observation and mitigation 
requirements. The mitigation measures discussed in Chapter 5 
(Mitigation), Section 5.3 (Procedural Mitigation to be Implemented) of 
the HSTT FEIS/OEIS include the maximum number of Lookouts the Navy can 
assign to each activity based on available manpower and resources; 
therefore, it would be impractical to add personnel to serve as 
additional Lookouts. For example, the Navy does not have available 
manpower to add Lookouts to use thermal detection systems in tandem 
with existing Lookouts who are using traditional observation 
techniques.
    The Defense Advanced Research Projects Agency funded six initial 
studies to test and evaluate infrared-based thermal detection 
technologies and algorithms to automatically detect marine mammals on 
an unmanned surface vehicle. Based on the outcome of these initial 
studies, follow-on efforts and testing are planned for 2018-2019. The 
Office of Naval Research Marine Mammals and Biology program funded a 
project (2013-2018) to test the thermal limits of infrared-based 
automatic whale detection technology. This project is focused on 
capturing whale spouts at two different locations featuring subtropical 
and tropical water temperatures, optimizing detector/classifier 
performance on the collected data, and testing system performance by 
comparing system detections with concurrent visual observations.
    The Office of Naval Research Marine Mammals and Biology program is 
currently funding an ongoing project (2013-2018) that is testing the 
thermal limits of infrared based automatic whale detection technology 
(Principal Investigators: Olaf Boebel and Daniel Zitterbart). This 
project is focused on (1) capturing whale spouts at two different 
locations featuring subtropical and tropical water temperatures; (2) 
optimizing detector/classifier performance on the collected data; and 
(3) testing system performance by comparing system detections with 
concurrent visual observations. In addition, Defense Advanced Research 
Projects Agency (DARPA) has funded six initial studies to test and 
evaluate current technologies and algorithms to automatically detect 
marine mammals (IR thermal detection being one of the technologies) on 
an unmanned surface vehicle. Based on the outcome of these initial 
studies, follow-on efforts and testing are planned for 2018-2019.
    The Navy plans to continue researching thermal detection systems 
for marine mammal detection to determine their effectiveness and 
compatibility with Navy applications. If the technology matures to the 
state where thermal detection is determined to be an effective 
mitigation tool during training and testing, NMFS and the Navy will 
assess the practicability of using the technology during training and 
testing events and retrofitting the Navy's observation platforms with 
thermal detection devices. The assessment will include an evaluation of 
the budget and acquisition process (including costs associated with 
designing, building, installing, maintaining, and manning the 
equipment); logistical and physical considerations for device 
installment, repair, and replacement (e.g., conducting engineering 
studies to ensure there is no electronic or power interference with 
existing shipboard systems); manpower and resource considerations for 
training personnel to effectively operate the equipment; and 
considerations of potential security and classification issues. New 
system integration on Navy assets can entail up to 5 to 10 years of 
effort to account for acquisition, engineering studies, and development 
and execution of systems training. The Navy will provide information to 
NMFS about the status and findings of Navy-funded thermal

[[Page 66889]]

detection studies and any associated practicability assessments at the 
annual adaptive management meetings.
    Passive Acoustic Monitoring--The Navy does employ passive acoustic 
monitoring when practicable to do so (i.e., when assets that have 
passive acoustic monitoring capabilities are already participating in 
the activity). For other explosive events, there are no platforms 
participating that have passive acoustic monitoring capabilities. 
Adding a passive acoustic monitoring capability (either by adding a 
passive acoustic monitoring device to a platform already participating 
in the activity, or by adding a platform with integrated passive 
acoustic monitoring capabilities to the activity, such as a sonobuoy) 
for mitigation is not practicable. As discussed in Chapter 5 
(Mitigation), Section 5.5.3 (Active and Passive Acoustic Monitoring 
Devices) of the HSTT FEIS/OEIS, there are significant manpower and 
logistical constraints that make constructing and maintaining 
additional passive acoustic monitoring systems or platforms for each 
training and testing activity impracticable. Additionally, diverting 
platforms that have passive acoustic monitoring platforms would impact 
their ability to meet their Title 10 requirements and reduce the 
service life of those systems.
    The use of real-time passive acoustic monitoring (PAM) for 
mitigation at the Southern California Anti-submarine Warfare Range 
(SOAR) exceeds the capability of current technology. The Navy has a 
significant research investment in the Marine Mammal Monitoring on Navy 
Ranges (M3R) system at three ocean locations including SOAR. However, 
this system was designed and intended to support marine mammal research 
for select species, and not as a mitigation tool. Marine mammal PAM 
using instrumented hydrophones is still under development and while it 
has produced meaningful results for marine species monitoring, 
abundance estimation, and research, it was not developed for nor is it 
appropriate for real-time mitigation. The ability to detect, classify, 
and develop an estimated position (and the associated area of 
uncertainty) differs across species, behavioral context, animal 
location vs. receiver geometry, source level, etc. Based on current 
capabilities, and given adequate time, vocalizing animals within an 
indeterminate radius around a particular hydrophone are detected, but 
obtaining an estimated position for all individual animals passing 
through a predetermined area is not assured. Detecting vocalizations on 
a hydrophone does not determine whether vocalizing individuals would be 
within the established mitigation zone in the timeframes required for 
mitigation. Since detection ranges are generally larger than current 
mitigation zones for many activities, this would unnecessarily delay 
events due to uncertainty in the animal's location and put at risk 
event realism.
    Furthermore, PAM at SOAR does not account for animals not 
vocalizing. For instance, there have been many documented occurrences 
during PAM verification testing at SOAR of small boats on the water 
coming across marine mammals such as baleen whales that were not 
vocalizing and therefore not detected by the range hydrophones. Animals 
must vocalize to be detected by PAM; the lack of detections on a 
hydrophone may give the false impression that the area is clear of 
marine mammals. The lack of vocalization detections is not a direct 
measure of the absence of marine mammals. If an event were to be moved 
based upon low-confidence localizations, it may inadvertently be moved 
to an area where non-vocalizing animals of undetermined species are 
present.
    To develop an estimated position for an individual, it must be 
vocalizing and its vocalizations must be detected on at least three 
hydrophones. The hydrophones must have the required bandwidth, and 
dynamic range to capture the signal. In addition, calls must be 
sufficiently loud so as to provide the required signal to noise ratio 
on the surrounding hydrophones. Typically, small odontocetes echolocate 
with a directed beam that makes detection of the call on multiple 
hydrophones difficult. Developing an estimated position of selected 
species requires the presence of whistles which may or may not be 
produced depending on the behavioral state. Beaked whales at SOAR 
vocalize only during deep foraging dives which occur at a rate of 
approximately 10 per day. They produce highly directed echolocation 
clicks that are difficult to simultaneously detect on multiple 
hydrophones. Current real-time systems cannot follow individuals and at 
best produce sparse positions with multiple false locations. The 
position estimation process must occur in an area with hydrophones 
spaced to allow the detection of the same echolocation click on at 
least three hydrophones. Typically, a spacing of less than 4 km in 
water depths of approximately 2 km is preferred. In the absence of 
detection, the analyst can only determine with confidence if a group of 
beaked whales is somewhere within 6 km of a hydrophone. Beaked whales 
produce stereotypic click trains during deep (<500 m) foraging dives. 
The presence of a vocalizing group can be readily detected by an 
analyst by examining the click structure and repetition rate. However, 
estimating position is possible only if the same train of clicks is 
detected on multiple hydrophones which is often precluded by the 
animal's narrow beam pattern. Currently, this is not an automated 
routine.
    In summary, the analytical and technical capabilities required to 
use PAM such as M3R at SOAR as a required mitigation tool are not 
sufficiently robust to rely upon due to limitations with near real-time 
classification and determining estimated positions. The level of 
uncertainty as to a species presence or absence and location are too 
high to provide the accuracy required for real-time mitigation. As 
discussed in Chapter 5 (Mitigation) of the HSTT FEIS/OEIS, existing 
Navy visual mitigation procedures and measures, when performed by 
individual units at-sea, still remain the most practical means of 
protection for marine species.
    Comment 35: Commenters commented that NMFS should add mitigation 
for other marine mammal stressors such as dipping sonar, pile driving, 
and multiple exposures near homeports.
    Response: The Navy implements a 200-yd shutdown for dipping sonar 
and a 100-yd exclusion zone for pile-driving. It is unclear what the 
commenter means by adding mitigation for ``multiple exposures'' near 
homeports, and therefore no explanation can be provided.
Mitigation Areas
Introduction
    The Navy included a comprehensive proposal of mitigation measures 
in their initial application that included procedural mitigations that 
reduce the likelihood of mortality, injury, hearing impairment, and 
more severe behavioral responses for most species. The Navy also 
included time/area mitigation that further protects areas where 
important behaviors are conducted and/or sensitive species congregate, 
which reduces the likelihood of takes that are likely to impact 
reproduction or survival (as described in the Mitigation Measures 
section of the final rule and the Navy's application). As a general 
matter, where an applicant proposes measures that are likely to reduce 
impacts to marine mammals, the fact that they are included in the 
proposal

[[Page 66890]]

and application indicates that the measures are practicable, and it is 
not necessary for NMFS to conduct a detailed analysis of the measures 
the applicant proposed (rather, they are simply included). However, it 
is necessary for NMFS to consider whether there are additional 
practicable measures that could also contribute to the reduction of 
adverse effects on the species or stocks through effects on annual 
rates of recruitment or survival. In the case of the Navy's HSTT 
application, we worked with the Navy prior to the publication of the 
proposed rule and ultimately the Navy agreed to increase geographic 
mitigation areas adjacent to the island of Hawaii to more fully 
encompass specific biologically important areas and the Alenuihaha 
Channel and to limit additional anti-submarine warfare mid-frequency 
active sonar (ASW) source bins (MF4) within some geographic mitigation 
areas.
    During the public comment period on the proposed rule, NMFS 
received numerous recommendations for the Navy to implement additional 
mitigation measures, both procedural and time/area limitations. 
Extensive discussion of the recommended mitigation measures in the 
context of the factors considered in the least practicable adverse 
impact analysis (considered in the Mitigation Measures section of the 
final rule and described below), as well as considerations of alternate 
iterations or portions of the recommended measures considered to better 
address practicability concerns, resulted in the addition of several 
procedural mitigations and expansion of multiple time/area mitigations 
(see the Mitigation Measures section in the final rule). These 
additional areas reflect, for example, concerns about blue whales in 
SOCAL and small resident odontocete populations in Hawaii (which 
resulted in expanded time/area mitigation), focus on areas where 
important behaviors and habitat are found (e.g., in BIAs), and 
enhancement of the Navy's ability to detect and reduce injury and 
mortality (which resulted in expanded monitoring before and after 
explosive events). Through extensive discussion, NMFS and the Navy 
worked to identify and prioritize additional mitigation measures that 
are likely to reduce impacts on marine mammal species or stocks and 
their habitat and are also possible for the Navy to implement.
    Following the publication of the 2013 HSTT MMPA incidental take 
rule, the Navy (and NMFS) were sued and the resulting settlement 
agreement prohibited or restricted Navy activities within specific 
areas in the HSTT Study Area. These provisional prohibitions and 
restrictions on activities within the HSTT Study Area were derived 
pursuant to negotiations with the plaintiffs in that lawsuit were 
specifically not evaluated or selected based on the type of thorough 
examination of best available science that occurs through the 
rulemaking process under the MMPA, or through related analyses 
conducted under the National Environmental Policy Act (NEPA) or the 
ESA. The agreement did not constitute a concession by the Navy as to 
the potential impacts of Navy activities on marine mammals or any other 
marine species, or to the practicability of the measures. The Navy's 
adoption of restrictions on its HSTT activities as part of a relatively 
short-term settlement does not mean that those restrictions are 
necessarily supported by the best available science, likely to reduce 
impacts to marine mammals species or stocks and their habitat, or 
practicable to implement from a military readiness standpoint over the 
longer term in the HSTT Study Area. Accordingly, as required by 
statute, NMFS analyzed the Navy's activities, impacts, mitigation and 
potential mitigation (including the settlement agreement measures) 
pursuant to the ``least practicable adverse impact'' standard to 
determine the appropriate mitigation to include in these regulations. 
Some of the measures included in the settlement agreement are included 
in the final rule, while some are not. Other measures that were not 
included in the settlement agreement are included in the final rule.
    Ultimately, the Navy adopted all mitigation measures that are 
practicable without jeopardizing its mission and Title 10 
responsibilities. In other words, a comprehensive assessment by Navy 
leadership of the final, entire list of mitigation measures concluded 
that the inclusion of any further mitigation beyond those measures 
identified here in the final rule would be entirely impracticable. NMFS 
independently reviewed the Navy's practicability determinations for 
specific mitigation areas and concurs with the Navy's analysis.
    As we outlined in the Mitigation Measures section, NMFS has 
reviewed Appendix K (Geographic Mitigation Assessment) in the Navy's 
HSTT FEIS/OEIS and information contained reflects the best available 
science as well as a robust evaluation of the practicability of 
different measures, and NMFS uses Appendix K to support our independent 
least practicable adverse impact analysis. Below is additional 
discussion regarding specific recommendations for mitigation measures.
    Comment 36: With respect to the national security exemption related 
to mitigation areas, a commenter recommended that NMFS should specify 
that authorization may be given only by high-level officers, consistent 
with the Settlement Agreement or with previous HSTT rulings.
    Response: The Navy provided the technical analyses contained in 
Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS 
that included details regarding changing the measure to the appropriate 
delegated Command designee (see specifically Appendix K, Section 
K.2.2.1 (Proposed Mitigation Areas within the HSTT Study Area), for 
each of the proposed areas). The commenter proposed ``authorization may 
be given only by high-level officers'' and therefore appears to have 
missed the designations made within the cited sections above since 
those do constitute positions that could only be considered ``high 
level officers.'' The decision would be delegated to high-level 
officers. This delegation has been clarified in the Final rule as 
``permission from the appropriate designated Command authority.''
SOCAL Areas
    Comment 37: NPS recommended that the Navy consider the following as 
it plans to conduct activities in the HSTT Study Area. NPS noted the 
units of the NPS system that occur near the Navy's training and testing 
locations in Southern California and which may be affected by noise 
including Channel Islands National Park (NP) and Cabrillo National 
Monument.
    Response: National Parks and marine protected areas in are 
addressed in Chapter 6 of the HSTT FEIS/OEIS. The Channel Islands 
National Marine Sanctuary consists of an area of 1,109 nmi\2\ around 
Anacapa Island, Santa Cruz Island, Santa Rosa Island, San Miguel Island 
and Santa Barbara Island to the south. Only 92 nmi\2\ of Santa Barbara 
Island, or about 8 percent of the Channel Island National Marine 
Sanctuary, occurs within the SOCAL portion of the HSTT Study Area, but 
the entirety of that piece is included in the Santa Barbara Mitigation 
Area. The Navy will continue to implement a mitigation area out to 6 
nmi of Santa Barbara Island, which includes a portion of the Channel 
Island National Marine Sanctuary and the Santa Barbara Marine Protected 
Area where the Navy will restrict the use of MF1 sonar sources and some 
explosive during training. Please refer to Figure 5.4-4 in the Navy's 
HSTT FEIS/OEIS shows the

[[Page 66891]]

spatial extent of the Santa Barbara Island mitigation area.
    Cabrillo National Monument only contains some intertidal areas, but 
no marine waters. No Navy activities overlap with the Cabrillo National 
Monument; therefore, no impacts are expected.
    Comment 38: A commenter recommended to extend the seasonality of 
the San Diego Arc Mitigation Area to December 31 for blue whales are 
present off southern California almost year round, and relatively 
higher levels from June 1 through December 31.
    Response: Analysis of the San Diego Arc Mitigation Area and its 
consideration for additional geographic mitigation is provided in the 
HSTT FEIS/OEIS in Appendix K (Geographic Mitigation Assessment), 
Section K.4.1.6 (San Diego (Arc) Blue Whale Feeding Area; Settlement 
Areas 3-A through 3-C, California Coastal Commission 3 nmi Shore Area, 
and San Diego Arc Area), Section K.5.5 (Settlement Areas within the 
Southern California Portion of the HSTT Study Area), and Section K.6.2 
(San Diego Arc: Area Parallel to the Coastline from the Gulf of 
California Border to just North of Del Mar). This analysis included 
consideration of seasonality and the potential effectiveness of 
restrictions to use of mid-frequency active sonar by Navy in the area. 
Based on the Appendix K (Geographic Mitigation Assessment) analyses, 
the Navy will implement additional mitigation within the San Diego Arc 
Mitigation Area, as detailed in Chapter 5 (Mitigation) Section 5.4.3 
(Mitigation Areas for Marine Mammals in the Southern California Portion 
of the Study Area) of the HSTT FEIS/OEIS, to further avoid or reduce 
impacts on marine mammals from acoustic and explosive stressors and 
vessel strikes from Navy training and testing in this location. Since 
the proposed rule, the Navy is now limiting MF1 surface ship hull-
mounted MFAS even further in the San Diego Arc Mitigation Area. The 
Navy will not conduct more than 200 hrs of MF1 MFAS in the combined 
areas of the San Diego Arc Mitigation Area and newly added San Nicholas 
Island and Santa Monica/Long Beach Mitigation Areas. As described in 
the proposed rule, the Navy will not use explosives that could 
potentially result in the take of marine mammals during large-caliber 
gunnery, torpedo, bombing, and missile (including 2.75'' rockets) 
activities during training and testing in the San Diego Mitigation 
Area. Regarding the recommended increase in seasonality to December 31, 
the San Diego Arc and current seasonality is based on the Biologically 
Important Area associated with this mitigation area (Calambokidis et 
al., 2017), which identifies the primary months for feeding. While blue 
whale calls have been detected in Southern California through December 
(Rice et al., 2017, Lewis and [Scaron]irovi[cacute], in press), given a 
large propagation range (10-50 km or more) for low-frequency blue whale 
vocalization, blue whale call detection from a Navy-funded single 
passive acoustic device near the San Diego Arc may not be a direct 
correlation with blue whale presence within the San Diego Arc from 
November through December. In addition, passive acoustic call detection 
data does not currently allow for direct abundance estimates. Calls may 
indicate some level of blue whale presence, but not abundance or 
individual residency time. In the most recent Navy-funded passive 
acoustic monitoring report including the one site in the northern San 
Diego Arc from June 2015 to April 2016, blue whale call detection 
frequency near the San Diego Arc starts declining in November after an 
October peak (Rice et al., 2017, [Scaron]irovi[cacute], personal 
communication). The newest Navy-funded research on blue whale movements 
from 2014 to 2017 along the U.S. West Coast based on satellite tagging, 
has shown that individual blue whale movement is wide ranging with 
large distances covered daily (Mate et al., 2017). Nineteen (19) blue 
whales were tagged in 2016, the most recent reporting year available 
(Mate et al., 2017). Only 5 of the 19 blue whales spent time in the 
SOCAL portion of the HSTT Study Area, and only spent a few days within 
the range complex (2-13 days). Average distance from shore for blue 
whales was 113 km. None of the 19 blue whales tagged in 2016 spent time 
within the San Diego Arc. From previous year efforts (2014-2015), only 
a few tagged blue whales passed through the San Diego Arc. In addition, 
Navy and non-Navy-funded blue whale satellite tagging studies started 
in the early 1990s and has continued irregularly through 2017. In 
general, most blue whales start a south-bound migration from the 
``summer foraging areas'' in the mid- to late-fall time period, unless 
food has not been plentiful, which can lead to a much earlier migration 
south. Therefore, while blue whales have been documented within the San 
Diego Arc previously, individual use of the area is variable, likely of 
short duration, and declining after October. Considering the newest 
passive acoustic and satellite tagging data, there is no scientific 
justification for extending the San Diego Arc Mitigation Area period 
from October 31 to December 31.
    Comment 39: A commenter recommended limiting all MF1 use within the 
San Diego Arc Mitigation Area. A commenter also recommended NMFS should 
carefully consider prohibiting use of other LFAS and MFAS during the 
time period the San Diego Arc Mitigation Areas is in place, and for the 
MTEs to be planned for other months of the year.
    Response: Since the proposed rule, the Navy is now limiting MF1 
surface ship hull-mounted MFAS even further in the San Diego Arc 
Mitigation Area. The Navy will not conduct more than 200 hrs of MF1 
MFAS in the combined areas of the San Diego Arc Mitigation Area and 
newly added San Nicholas Island and Santa Monica/Long Beach Mitigation 
Areas. Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/
OEIS discusses the Navy's analysis of MFAS restrictions within the San 
Diego Arc Mitigation Area. Other training MFAS systems are likely to be 
used less frequently in the vicinity of the San Diego Arc area than 
surface ship MFAS. Given water depths, the San Diego Arc area is not 
conducive for large scale anti-submarine warfare exercises, nor near 
areas where other anti-submarine warfare training and testing occurs. 
Due to the presence of existing Navy subareas in the southern part of 
the San Diego Arc, a limited amount of helicopter dipping MFAS could 
occur. These designated range areas are required for proximity to 
airfields in San Diego such as Naval Air Station North Island and for 
airspace management. However, helicopters only used these areas in the 
Arc for a Kilo Dip. A Kilo Dip is a functional check of approximately 
1-2 pings of active sonar to confirm the system is operational before 
the helicopter heads to more remote offshore training areas. This 
ensures proper system operation and avoids loss of limited training 
time, expenditure of fuel, and cumulative engine use in the event of 
equipment malfunction. The potential effects of dipping sonar have been 
accounted for in the Navy's analysis. Dipping sonar is further 
discussed below in Comment 40.
    Comment 40: A commenter recommended prohibiting the use of air-
deployed mid-frequency active sonar in the San Diego Arc Mitigation 
Area.
    Response: The HSTT FEIS/OEIS and specifically Appendix K 
(Geographic Mitigation Assessment) discuss the Navy's analysis of mid-
frequency and low-frequency active sonar restrictions within the San 
Diego Arc. Other sonar systems are likely to be used less frequently in 
the vicinity of the San

[[Page 66892]]

Diego Arc than surface ship mid-frequency active sonars. In regard to 
the recommendation to prohibit ``air-deployed'' or dipping mid-
frequency active sonar, the only helicopter dipping sonar activity that 
would likely be conducted in the San Diego Arc area is a Kilo Dip, 
which occurs relatively infrequently and involves a functional check of 
approximately 1-2 pings of active sonar before moving offshore beyond 
the San Diego Arc to conduct the training activity. During use of this 
sonar, the Navy will implement the procedural mitigation as described 
in Section 5.3.2.1 (Active Sonar). The Kilo Dip functional check needs 
to occur close to Naval Air Station North Island in San Diego to insure 
all systems are functioning properly, before moving offshore. This 
ensures proper system operation and avoids loss of limited training 
time, expenditure of fuel, and cumulative engine use in the event of 
equipment malfunction. The potential effects of dipping sonar have been 
accounted for in the Navy's analysis. Further, due to lower power 
settings for dipping sonar, potential behavioral impact ranges of 
dipping sonar are significantly lower than surface ship sonars. For 
example, the HSTT average modeled range to temporary threshold shift of 
dipping sonar for a 1-second ping on low-frequency cetacean (i.e., blue 
whale) is 77 m (HSTT FEIS/OEIS Table 3.7-7). This range is easily 
monitored for large whales by a hovering helicopter and is accounted 
for in the Navy's proposed mitigation ranges for dipping sonars. 
Limited ping time and lower power settings therefore would limit the 
impact from dipping sonar to any marine mammal species. It should be 
pointed out that the commenter's recommendation is based on new Navy 
behavioral response research specific to beaked whales (Falcone et al., 
2017). The Navy relied upon the best science that was available to 
develop behavioral response functions in consultation with NMFS for the 
HSTT FEIS/OEIS. The article cited in the comment (Falcone et al., 2017) 
was not available at the time the HSTT EIS/OEIS was published. The new 
information and data presented in the article was thoroughly reviewed 
when it became available and further considered in discussions with 
some of the paper's authors. Many of the variables requiring further 
analysis for beaked whales and dipping sonar impact assessment are 
still being researched under continued Navy funding through 2019. The 
small portion of designated Kilo Dip areas that overlap the southern 
part of the San Diego Arc is not of sufficient depth for preferred 
habitat of beaked whales (see Figure 2.1-9 in the HSTT FEIS/OEIS). 
Further, passive acoustic monitoring for the past several years in the 
San Diego Arc confirms a lack of beaked whale detections (Rice et al., 
2017). Also, behavioral responses of beaked whales from dipping and 
other sonars cannot be universally applied to other species including 
blue whales. Navy-funded behavioral response studies of blue whales to 
simulated surface ship sonar has demonstrated there are distinct 
individual variations as well as strong behavioral state considerations 
that influence any response or lack of response (Goldbogen et al., 
2013).
    Comment 41: A commenter recommends requiring vessel speed 
restrictions within the San Diego Arc Mitigation Area.
    Response: Previously, the Navy commissioned a vessel density and 
speed report for the HSTT Study Area (CNA, 2016). Based on an analysis 
of Navy ship traffic in the HSTT Study Area between 2011 and 2015, 
median speed of all Navy vessels within Southern California is 
typically already low, with median speeds between 5 and 12 kn (CAN, 
2016). Slowest speeds occurred closer to the coast including the 
general area of the San Diego Arc and approaches to San Diego Bay. The 
presence and transits of commercial and recreational vessels, numbering 
in the many hundreds, far outweighs the presence of Navy vessels. 
According the the SARs, blue whale mortality and injuries attributed to 
commercial ship strikes in California waters was zero in the most 
recent reporting period between 2011 and 2015 (Carretta et al., 2017a). 
However, ship strikes were implicated in the deaths of four blue whales 
and the serious injury of a fifth whale between 2009 and 2013 (Carretta 
et al., 2015). There has been no confirmed Navy ship strike to a blue 
whale in the entire Pacific over the 13-year period from 2005 to 2017. 
To minimize the possibility of ship strike in the San Diego Arc 
Mitigation Area, the Navy will implement procedural mitigation for 
vessel movements based on guidance from NMFS for vessel strike 
avoidance. The Navy will also issue seasonal awareness notification 
messages to all Navy vessel of blue, fin, and gray whale occurrence to 
increase ships awareness of marine mammal presence as a means of 
improving detection and avoidance of whales in SOCAL. When developing 
the mitigation for this 2018-2023 rule, the Navy analyzed the potential 
for implementing additional types of mitigation, such as developing 
vessel speed restrictions within the HSTT Study Area. The Navy 
determined that based on how the training and testing activities will 
be conducted within the HSTT Study Area under the planned activities, 
vessel speed restrictions would be incompatible with the practicability 
assessment criteria for safety, sustainability, and Title 10 
requirements, as described in Section 5.3.4.1 (Vessel Movement) of the 
HSTT FEIS/OEIS.
    Comment 42: A commenter recommended prohibiting the use of air-
deployed mid-frequency active sonar in the Santa Barbara Island 
Mitigation Area.
    Response: The commenter requested to prohibit ``air-deployed'' mid-
frequency active sonar is based on one paper (Falcone et al., 2017), 
which is a Navy-funded project designed to study behavioral responses 
of a single species, Cuvier's beaked whales, to mid-frequency active 
sonar. The Navy relied upon the best science that was available to 
develop behavioral response functions for beaked whales and other 
marine mammals in consultation with NMFS for the HSTT FEIS/OEIS. The 
article cited in the comment (Falcone et al., 2017) was not available 
at the time the HSTT DEIS/OEIS was published but does not change the 
HSTT FEIS/OEIS criteria or conclusions. The new information and data 
presented in the article were thoroughly reviewed when they became 
available and further considered in discussions with some of the 
paper's authors. Many of the variables requiring further analysis for 
beaked whales and dipping sonar impact assessment are still being 
researched under continued Navy funding through 2019.
    Behavioral responses of beaked whales from dipping and other sonars 
cannot be universally applied to other marine mammal species. For 
example, Navy-funded behavioral response studies of blue whales to 
simulated surface ship sonar has demonstrated there are distinct 
individual variations as well as strong behavioral state considerations 
that influence any response or lack of response (Goldbogen et al., 
2013). The same conclusion on the importance of exposure and behavioral 
context was stressed by Harris et al. (2017). Therefore, it is expected 
that other species would also have highly variable individual responses 
ranging from some response to no response to any anthropogenic sound. 
This variability is accounted for in the Navy's current behavioral 
response curves described in the HSTT FEIS/OEIS and supporting 
technical reports.

[[Page 66893]]

    The potential effects of dipping sonar have been rigorously 
accounted for in the Navy's analysis. Parameters such as power level 
and propagation range for typical dipping sonar use are factored into 
HSTT acoustic impact analysis along with guild specific criteria and 
other modeling variables as detailed in the HSTT FEIS/OEIS and 
associated technical reports for criteria and acoustic modeling. Due to 
lower power settings for dipping sonar, potential impact ranges of 
dipping sonar are significantly lower than surface ship sonars. For 
example, the HSTT average modeled range to temporary threshold shift of 
dipping sonar for a 1-second ping on low-frequency cetacean (i.e., blue 
whale) is 77 m, and for mid-frequency cetaceans including beaked whales 
is 22 m (HSTT FEIS/OEIS Table 3.7-7). This range is monitored for 
marine mammals by a hovering helicopter and is accounted for in the 
Navy's proposed mitigation ranges for dipping sonars (200 yd. or 183 
m). Limited ping time and lower power settings therefore would limit 
the impact from dipping sonar to any marine mammal species.
    For other marine mammal species, the small area around Santa 
Barbara Island does not have resident marine mammals, formally 
identified biologically important areas, nor is it identified as a 
breeding or persistent foraging location for cetaceans. Instead, the 
same marine mammals that range throughout the offshore Southern 
California area could pass at some point through the marine waters of 
Santa Barbara Island. As discussed in Appendix K (Geographic Mitigation 
Assessment) of the HSTT FEIS/OEIS, the Navy is already proposing year-
round limitations to mid-frequency active sonar and larger explosive 
use. The Navy will not use MF1 surface ship hull-mounted mid-frequency 
active sonar during training or testing, or explosives that could 
potentially result in the take of marine mammals during medium-caliber 
or large-caliber gunnery, torpedo, bombing, and missile (including 
2.75'' rockets) activities during training in the Santa Barbara Island 
Mitigation Area. Other mid-frequency active sonar systems for which the 
Navy is seeking authorization within SOCAL are used less frequently 
than surface ship sonars, and more importantly are of much lower power 
with correspondingly lower propagation ranges and reduced potential 
behavioral impacts.
    Comment 43: A commenter recommended prohibiting other sources of 
mid-frequency active sonar in the Santa Barbara Mitigation Area.
    Response: Appendix K (Geographic Mitigation Assessment) discusses 
the Navy's analysis of mid-frequency active sonar restrictions around 
Santa Barbara Island. Other training mid-frequency active sonar (MFAS) 
systems are likely to be used less frequently in the vicinity Santa 
Barbara Island than surface ship mid-frequency active sonars. Although 
not prohibiting the use of other sources of MFAS, the Navy will not use 
MF1 surface ship hull-mounted mid-frequency active sonar during 
training or testing, or explosives that could potentially result in the 
take of marine mammals during medium-caliber or large-caliber gunnery, 
torpedo, bombing, and missile (including 2.75'' rockets) activities 
during training in the Santa Barbara Island Mitigation Area.
    Comment 44: A commenter recommended implementing vessel speed 
restrictions in the Santa Barbara Island Mitigation Area (Channel 
Islands Sanctuary Cautionary Area).
    Response: The Channel Islands Sanctuary Cautionary Area was renamed 
the Santa Barbara Island Mitigation Area for the proposed rule. All 
locations within the HSTT Study Area have been used for Navy training 
and testing for decades. There has been no scientific evidence to 
indicate the Navy's activities are having adverse effects on 
populations of marine mammals, many of which continue to increase in 
number or are maintaining populations based on what regional conditions 
can support. This includes any marine mammal population that may 
transit through the Santa Barbara Island Mitigation Area. For example, 
the most recent NMFS U.S. West Coast survey findings (Moore and Barlow, 
2017) encountered the highest estimated abundance of Mesoplodon beaked 
whales in the California Current since 1991. Multiple other surveys, 
monitoring efforts, and research projects continue to encounter long-
term resident individuals such as populations of beaked whales in 
higher densities within the HSTT Study Area where various sonar systems 
have been in use for decades; see for example citation in the HSTT 
FEIS/OEIS to Debich et al. (2015a, 2015b), Falcone and Schorr (2012, 
2014), Hildebrand et al. (2009), Moretti (2016), [Scaron]irovi[cacute] 
et al. (2016), and Smultea and Jefferson (2014). The newest Navy-funded 
research, which was not available when the HSTT FEIS/OEIS was issued, 
continue to support the regular and repeated occurrence of marine 
mammal populations in HSTT including those thought most susceptible to 
behavioral response to anthropogenic sounds (DiMarzio et al., 2018; 
Lewis and [Scaron]irovi[cacute], in press; Moretti et al., 2017; Schorr 
et al., 2018; [Scaron]irovi[cacute] et al., 2016, 2017, 2018; 
[Scaron]irovi[cacute] et al., 2018). Navy research and monitoring 
funding continues within the HSTT Study Area under current NMFS MMPA 
and ESA permits, and is planned through the duration of any future 
permits. Given the lack of effects to marine mammal populations in the 
HSTT Study Area from surface ship sonars, the effects from 
intermittent, less frequent use of lower powered dipping mid-frequency 
active sonar or other mid-frequency active sonar and low-frequency 
sonars would also not significantly affect local populations.
    Additionally, here has not been any Navy ship strike to marine 
mammals in SOCAL over the 8-year period from 2010-2018, and there has 
never been a Navy strike within the boundary of the Channel Islands 
National Marine Sanctuary over the course of strike record collection 
dating back 20 years. Therefore, ship strike risk to marine mammals 
transiting the Santa Barbara Island Mitigation Area is minimal. 
Additionally, as detailed in the analysis in the HSTT FEIS/OEIS Section 
3.7.3.4.1 (Impacts from Vessels and In-Water Devices) and in Appendix K 
(Geographic Mitigation Assessment), there are important differences 
between most Navy vessels and their operation and commercial ships that 
individually make Navy vessels much less likely to strike a whale. Navy 
vessels already operate at a safe speed given a particular transit or 
activity need. This also includes a provision to avoid large whales by 
500 yd; so long as safety of navigation and safety of operations is 
maintained. Previously, the Navy commissioned a vessel density and 
speed report for HSTT (CNA, 2016). Based on an analysis of Navy ship 
traffic in HSTT between 2011 and 2015, the average speed of all Navy 
vessels within Southern California is typically already low, with 
median speeds between 5 and 12 kn (CNA, 2016). Slowest speeds occurred 
closer to the coast and islands. However, sometimes during training or 
testing activities, higher speeds are required.
    Finally, given the lack of population impact to marine species 
throughout SOCAL from Navy activities, lack of significant and repeated 
use of the small portion of waters within the Santa Barbara Island 
Mitigation Area by marine mammals, anticipated low individual residency 
times within the Mitigation Area, application of mitigation and 
protective measures as outlined in the HSTT FEIS/OEIS, documented safe 
speeds Navy vessels already navigate by, detailed

[[Page 66894]]

assessments of realistic training and testing requirements and 
potential impacts of further restrictions, the Navy has adequately 
defined the most practicable mitigation measures in the HSTT FEIS/OEIS 
and Appendix K (Geographic Mitigation Assessment).
    Comment 45: A commenter recommended additional mitigation areas for 
important beaked whale habitat in the Southern California Bight. A 
commenter asserted that it is important to focus substantial management 
efforts on beaked whales within the Navy's SOCAL Range Complex, which 
sees the greatest annual amount of sonar and explosives activity of any 
Navy range in the Pacific.
    Response: The basis for this comment includes incorrect or outdated 
information or information that does not reflect the environment 
present in the HSTT Study Area, such as, ``. . .beaked whale 
populations in the California Current have shown significant, possibly 
drastic declines in abundance over the last twenty years.'' The 
citation provided in the footnote to the comment and postulated 
``decline'' was for beaked whales up until 2008 (which does not take 
into account information from the last 10 years) and was a postulated 
trend for the entire U.S. West Coast, not data which is specific to the 
HSTT Study Area. As noted in Section 3.7.3.1.1.7 (Long-Term 
Consequences) of the HSTT FEIS/OEIS, the postulated decline was in fact 
not present within the SOCAL portion of the HSTT Study Area, where 
abundances of beaked whales have remained higher than other locations 
off the U.S. West Coast. In addition, the authors of the 2013 citation 
(Moore and Barlow, 2013) have published trends based on survey data 
gathered since 2008 for beaked whales in the California Current, which 
now includes the highest abundance estimate in the history of these 
surveys (Barlow 2016; Carretta et al., 2017; Moore and Barlow, 2017). 
Also, when considering the portion of the beaked whale population 
within the SOCAL portion of the HSTT Study Area and as presented in the 
HSTT FEIS/OEIS, multiple studies have documented continued high 
abundance of beaked whales and the long-term residency of documented 
individual beaked whales, specifically where the Navy has been training 
and testing for decades (see for example Debich et al., 2015a, 2015b; 
Dimarzio et al., 2018; Falcone and Schorr, 2012, 2014; Hildebrand et 
al., 2009; Moretti, 2016; Schorr et al., 2018; [Scaron]irovi[cacute] et 
al., 2016; Smultea and Jefferson, 2014). There is no evidence that 
there have been any population-level impacts to beaked whales resulting 
from Navy training and testing in the SOCAL portion of the HSTT Study 
Area. The Navy did provide analysis and consideration of additional 
geographic mitigation for beaked whales in the Southern California 
Bight in Appendix K (Geographic Mitigation Assessment), Section K.7.2 
(Southern California Public Comment Mitigation Area Assessment) and 
specifically Section K.7.2.7 (Northern Catalina Basin and the San 
Clemente Basin) of the HSTT FEIS/OEIS regarding the stated concern over 
the possible presence of Perrin's beaked whale. See Chapter 5 
(Mitigation), Section 5.4.1.2 (Mitigation Area Assessment) of the HSTT 
FEIS/OEIS for additional details regarding the assessments of areas 
considered for mitigation.
    Comment 46: A commenter recommended additional mitigation areas in 
the San Nicholas Basin. A commenter notes that the settlement agreement 
established a ``refuge'' from sonar and explosives activities in a 
portion of the whales' secondary habitat, outside the Southern 
California Anti-submarine Warfare Range (SOAR), with more management 
effort being necessary in the long term a commenter recommended at a 
minimum that NMFS should prescribe the ``refuge'' during the next five-
year operation period and should consider all possible habitat-based 
management efforts, including but not limited to the expansion of this 
area further south towards SOAR, to address impacts on the small 
population of Cuvier's beaked whales associated with San Clemente 
Island. A commenter also commented the energetic costs of displacement 
of beaked whales into sub-optimal foraging habitat outweigh the costs 
of repeated sonar exposure for whale survival, while creating 
conditions of a population sink, such as has been seen on the Navy's 
AUTEC range (Claridge 2013).
    Response: Navy did provide analysis and consideration of additional 
geographic mitigation for beaked whales in the San Nicolas Basin in 
Appendix K (Geographic Mitigation Assessment), Section K.7.2 (Southern 
California Public Comment Mitigation Area Assessment) and specifically 
Section K.7.2.1 (San Nicolas Basin) of the HSTT FEIS/OEIS. See Chapter 
5 (Mitigation), Section 5.4.1.2 (Mitigation Area Assessment) of the 
HSTT FEIS/OEIS for additional details regarding the assessments of 
areas considered for mitigation.
    Within San Nicolas Basin, there is a documented, recurring number 
of Cuvier's beaked whales strongly indicating that the Navy's 
activities areis not having a population-level impact to this species. 
This is supported by repeated visual re-sighting rates of individuals, 
sightings of calves and, more importantly, reproductive females, and 
passive acoustic assessments of steady vocalization rates and abundance 
over at least the most recent seven-year interval. It is incorrect to 
consider as fact that there is a ``population sink, such as has been 
seen on the Navy's AUTEC range. In the citation provided (Claridge 
2013), that statement is merely a hypothesis, yet to be demonstrated.
    The Navy has been funding Cuvier's beaked whale research 
specifically in San Nicolas Basin since 2006. This research is planned 
to continue for at least the next five years through the duration of 
the planned HSTT MMPA permit. Cumulative from 2006 to 2016, over 170 
individual Cuvier's beaked whales have been catalogued within San 
Nicolas Basin. Schorr et al. (2018) state for the most recent field 
season from 2016 to 2017 that: Identification photos of suitable 
quality were collected from 69 of the estimated 81 individual Cuvier's 
beaked whales encountered in 2016-2017. These represented 48 unique 
individuals, with eight of these whales sighted on two different days, 
and another three on three different days during the study period. 
Nineteen (39 percent) of these whales had been sighted in previous 
years. Many more whales identified in 2016 had been sighted in a 
previous year (16/28 individuals, 57 percent), compared to 2017 (5/22 
individuals, 23 percent), though both years had sightings of whales 
seen as early as 2007. There were three adult females photographed in 
2016 that had been sighted with calves in previous years, one of which 
was associated with her second calf. Additionally, a fourth adult 
female, first identified in 2015 without a calf, was subsequently 
sighted with a calf. The latter whale was sighted for a third 
consecutive year in 2017, this time without a calf, along with two 
other adult females with calves who had not been previously sighted. 
These sightings of known reproductive females with and without calves 
over time (n = 45) are providing critically needed calving and weaning 
rate data for Population Consequences of Disturbance (PcoD) models 
currently being developed for this species on SOAR.
    In 2018, an estimate of overall abundance of Cuvier's beaked whales 
at the Navy's instrumented range in San Nicolas Basin was obtained 
using new dive-counting acoustic methods and an archive of passive 
acoustic M3R data representing 35,416 hours of data (DiMarzio, 2018; 
Moretti, 2017). Over the seven-year interval from 2010-2017,

[[Page 66895]]

there was no observed change and perhaps a slight increase in annual 
Cuvier's beaked whale abundance within San Nicolas Basin (DiMarzio 
2018). There does appear to be a repeated dip in population numbers and 
associated echolocation clicks during the fall centered around August 
and September (DiMarzio, 2018; Moretti, 2017). A similar August and 
September dip was noted by researchers using stand-alone off-range 
bottom passive acoustic devices in Southern California (Rice et al., 
2017; [Scaron]irovi[cacute] et al., 2016). This dip in abundance 
documented over 10 years of monitoring may be tied to some as yet 
unknown population dynamic or oceanographic and prey availability 
dynamic. It is unknown scientifically if this represents a movement to 
different areas by parts of the population, or a change in behavioral 
states without movement (i.e., breeding verse foraging). Navy training 
and testing events are spatially and temporally spread out across the 
SOCAL portion of the HSTT Study Area. In some years events occur in the 
fall, yet in other years events do not. Yet, the same dip has 
consistently been observed lending further evidence this is likely a 
population biological function.
    Comment 47: A commenter recommended additional mitigation areas in 
the Santa Catalina Basin. A commenter commented that there is likely a 
small, resident population of Cuvier's beaked whales resides in the 
Santa Catalina Basin and that this population is subject to regular 
acoustic disturbance due to the presence of the Shore Bombardment Area 
(SHOBA) and 3803XX. The population may also be exposed to training 
activities that occupy waters between Santa Catalina and San Clemente 
Islands. Similar to the San Nicholas population, the settlement 
agreement established a ``refuge'' from sonar and explosives activities 
in the northern portion of the Santa Catalina Basin. A commenter 
recommended that, at a minimum the Navy should carefully consider 
implementing the ``refuge'' during the next five-year authorization 
period and should continue to consider all possible habitat-based 
management efforts to address impacts on the population.
    Response: The water space areas mentioned in the comment as 
``(SHOBA)'' off the southern end of San Clemente Island are waters 
designated as Federal Danger and Safety Zones via formal rule making 
(Danger Zone--33 CFR 334.950 and Safety Zone--33 CFR 165.1141) because 
they are adjacent to the shore bombardment impact area that is on land 
at the southern end of San Clemente Island. Waters designated as 
``3803XX,'' which are associated with the Wilson Cove anchorages and 
moorings, where ship calibration tests, sonobuoy lot testing, and 
special projects take place, are designated as Federal Safety and 
Restricted Zones via formal rule making (Safety Zone--33 CFR 165.1141 
and Restricted Zone--33 CFR 334.920).
    The comment states a concern that a population of Cuvier's beaked 
whale is, ``subject to regular acoustic disturbance due to the presence 
of the Shore Bombardment Area,'' is not correct. The SHOBA is a naval 
gun impact area located on land at the southern end of San Clemente 
Island. This area is an instrumented land training range used for a 
variety of bombardment training and testing activities. The in-water 
administrative boundary for SHOBA does not delineate the locations 
where a ship firing at land targets must be located and does not 
represent where gunfire rounds are targeted. The water area in Santa 
Catalina Basin is a controlled safety zone in the very unlikely event a 
round goes over the island and lands in the water. With the modern 
advent of better precision munitions, computers, and advanced fire 
control, that probability is very remote. Navy vessels use the waters 
south of San Clemente Island (SHOBA West and SHOBA East) from which to 
fire into land targets on southern San Clemente Island (see the HSTT 
FEIS/OEIS Figure 2.1-7). Therefore, there would not be any underwater 
acoustic disturbance to Cuvier's beaked whales located within the Santa 
Catalina Basin from in-water explosives or ship firing.
    Comment 48: A commenter recommended additional mitigation areas for 
the southernmost edge of the California Current, west of Tanner and 
Cortes Banks. In light of the importance of the Southernmost edge of 
the California Current, west of Tanner and Cortes banks, Commenters 
recommend assessing the designation of the southern offshore waters of 
the Southern California Bight as a seasonal time-area management area 
for Cuvier's beaked whales between November and June. The approximate 
coordinates are 32.75 N, 119.46 W (referenced as Site E). As part of 
this assessment, a commenter recommended that the boundaries be refined 
via expert consideration of acoustic and other relevant information 
pertaining to beaked whale biology and bathymetric and oceanographic 
data.
    Response: Baumann-Pickering et al. (2014a, b, 2015), as the 
commenter referenced, did not specify this area as biologically 
important and the author's data only indicated there have been 
detections of the Cuvier's beaked whales within this area. Further, the 
species is widely distributed within Southern California and across the 
Pacific with almost all suitable deep water habitat greater than 800 m 
in Southern California conceivably containing Cuvier's beaked whales. 
Only limited population vital rates exist for beaked whales, covering 
numbers of animals, populations vs. subpopulations determination, and 
residency time for individual animals (Schorr et al., 2017, 2018). The 
science of passive acoustic monitoring is positioned to answer some 
questions on occurrence and seasonality of beaked whales, but cannot as 
of yet address all fundamental population parameters including 
individual residency time.
    Furthermore, while passive acoustic monitoring within Southern 
California has been ongoing for 28 years, with many sites funded by the 
Navy, not all sites have been consecutively monitored for each year. 
All of the single bottom-mounted passive acoustic devices used for the 
analysis by Baumann-Pickering et al. (2014a, b, 2015), and used in the 
comment to support its argument, are not continuous and have various 
periodicities from which data have been collected. Specifically, 
devices have been deployed and removed from various locations with some 
sites having multiple years of data, others significantly less, with 
perhaps just a few months out of a year. For instance, Site E, located 
west of Tanner and Cortes Banks and used by the commenter to justify 
restrictions in this area, was only monitored for 322 days from 
September 2006 through July 2009 (obtaining slightly less than a full 
year's worth of data).
    Site E was also used again for another 63 days from Dec 2010 
through February 2011. During this second monitoring period at Site E, 
Gassman et al. (2015) reported detection of only three Cuvier's beaked 
whales over six separate encounters with time intervals of 10-33 
minutes. As sources of data associated with a single monitoring point, 
the two monitoring episodes conducted at Site E may not be indicative 
of Cuvier's beaked whale presence at other locations within Southern 
California, which lack comparable monitoring devices. Nor would they be 
indicative of overall importance or lack of importance of the area west 
of Tanner and Cortes Banks. Further, more recent acoustic sampling of 
bathymetrically featureless areas off Southern California with drifting 
hydrophones conducted by NMFS, detected many beaked whales over abyssal 
plains and not associated with

[[Page 66896]]

slope or seamount features. This counters a common misperception that 
beaked whales are primarily found over slope waters, in deep basins, or 
over seamounts (Griffins and Barlow 2016).
    Most importantly, older passive acoustic data prior to 2009 may not 
be indicative of current or future occurrence of beaked whales, 
especially in terms of potential impact of climate change on species 
distributions within Southern California. To summarize, these limited 
periods of monitoring (322 days in a three-year period prior to 2010 
and 63 days in 2011) may or may not be reflective of current beaked 
whale distributions within Southern California and into the future. 
Furthermore, passive acoustic-only detection of beaked whales, without 
additional population parameters, can only determine relative 
occurrence, which could be highly variable over sub-regions and through 
time.
    While Cuvier's beaked whales have been detected west of Tanner and 
Cortes Banks, as noted above this species is also detected in most all 
Southern California locations greater than 800 m in depth. Furthermore, 
the Navy has been training and testing in and around Tanner and Cortes 
Banks with the same basic systems for over 40 years, with no evidence 
of any adverse impacts having occurred. Further, there are no 
indications that Navy training and testing in the Southern California 
portion of the HSTT Study Area has had any adverse impacts on 
populations of beaked whales in Southern California. In particular, a 
re-occurring population of Cuvier's beaked whales co-exists within San 
Nicolas Basin to the east, an area with significantly more in-water 
sonar use than west of Tanner and Cortes Banks.
    To gain further knowledge on the presence of beaked whales in 
Southern California, the Navy continues to fund additional passive 
acoustic field monitoring, as well as research advancements for density 
derivation from passive acoustic data. For the five-year period from 
2013 to 2017, U.S. Pacific Fleet on behalf of the U.S. Navy funded 
$14.2 million in marine species monitoring within Hawaii and Southern 
California. Specifically, in terms of beaked whales, the Navy has been 
funding beaked whale population dynamics, tagging, and passive acoustic 
studies within the HSTT Study Area since 2007 (DiMarzio et al., 2018; 
Moretti, 2017; Rice et al., 2017, Schorr et al., 2017, 2018; 
[Scaron]irovi[cacute], et al., 2017). Variations of these efforts are 
planned to continue through the duration of the next HSTT MMPA permit 
cycle using a variety of passive acoustic, visual, tagging, photo ID, 
and genetics research tools. This Navy effort is in addition and 
complementary to any planned NMFS efforts for beaked whales and other 
marine mammals. For instance, the Navy is co-funding with NMFS and the 
Bureau of Ocean Energy Management a planned Summer-Fall 2018 visual and 
passive acoustic survey along the U.S. West Coast and off Baja Mexico. 
New passive detection technologies focusing on beaked whales will be 
deployed during these surveys (similar to Griffiths and Barlow, 2016). 
The Navy continues SOCAL beaked whale occurrence and impact studies 
with additional effort anticipated through 2020.
    Analysis of the southernmost edge of the California Current, west 
of Tanner-Cortes Bank and the presence of Cuvier's beaked whales was 
addressed in Appendix K (Geographic Mitigation Assessment), Section 
K.7.2.4 (Southernmost Edge of California Current, West of Tanner-Cortes 
Bank) and Section K.7.2.6 (Cuvier's Beaked Whale Habitat Areas 
Mitigation Assessment) of the HSTT FEIS/OEIS. Also see Chapter 3, 
Section 3.7.2.3.24 (Cuvier's Beaked Whale (Ziphius cavirostris)) of the 
HSTT FEIS/OEIS for additional information regarding this species.
    As noted in Appendix K (Geographic Mitigation Assessment), the 
waters west of Tanner and Cortes Banks are also critical to the Navy's 
training and testing activities; therefore, it is not practicable to 
preclude activities within that water space in the SOCAL portion of the 
HSTT Study Area. Reasonable mitigation measures, as discussed in 
Appendix K (Geographic Mitigation Assessment), would limit the impact 
of training and testing on marine mammals, and especially beaked 
whales, in this area.
    Given that there is no evidence that Navy training and testing 
activities are having significant impacts to population of beaked 
whales anywhere in the SOCAL portion of the HSTT Study Area, the 
uncertainty of current use by Cuvier's beaked whales of the area west 
of Tanner and Cortes Banks, the fact that general occurrence of beaked 
whales in Southern California may not necessarily equate to factors 
typically associated with biologically important areas, and 
consideration of the importance of Navy training and testing activities 
in the areas around Tanner and Cortes Banks discussed in Appendix K 
(Geographic Mitigation Assessment) of the HSTT FEIS/OEIS, additional 
geographic mitigation specifically for the area west of Tanner and 
Cortes Banks is not warranted.
    As noted in Appendix K (Geographic Mitigation Assessment) and 
Chapter 5 (Mitigation), Section 5.3 (Procedural Mitigation to be 
Implemented) of the HSTT FEIS/OEIS, the Navy will continue to implement 
procedural mitigation measures throughout the HSTT Study Area.
    Comment 49: A commenter commented that the same long-term passive 
acoustic study of the Southern California Bight as discussed for 
Cuvier's beaked whales above in Comment 48 also suggests that southern-
central waters represent biologically important habitat for Perrin's 
beaked whale. A commenter recommended that the Northern Catalina Basin 
and the waters southeast of Santa Catalina Island (approximate 
coordinates of 33.28 N, -118.25 W), and the San Clemente Basin 
(approximate coordinates of 32.52 N, -118.32 W), both based on location 
of HARP deployments (referenced as sites ``A'' and ``S''), be 
considered as management areas for Perrin's beaked whales. A commenter 
recommended that the boundaries of any restrictions be established via 
expert consideration.
    Response: All of the single bottom-mounted passive acoustic devices 
used for the analysis by Baumann-Pickering et al. (2014) and used by 
the commenter to support their argument are not continuous and have 
various periodicities for which data have been collected. As single 
point sources of data, these passive acoustic devices may not be 
indicative of Perrin's beaked whale presence at other locations within 
Southern California without comparable devices. Nor would older data 
prior to 2009 be indicative of current or future occurrence especially 
in terms of potential impact of climate change on species 
distributions.
    Navy-funded passive acoustic monitoring within the SOCAL portion of 
the HSTT Study Area has been ongoing for the past 21 years, but not all 
areas are monitored continuously, and devices have been deployed and 
removed from various locations. Santa Catalina Basin was only monitored 
from August 2005 to July 2009. Santa Catalina Basin has not been 
monitored under Navy funding since 2009 because other areas in Southern 
California were prioritized for passive acoustic device placement by 
the researchers. For San Clemente Island, the single monitoring site 
``S'' used in Baumann-Pickering et al. (2014) and cited as the source 
of the comment's claim for San Clemente Basin was only deployed for a 
limited time of approximately 1.5 years, resulting in 409 days of data 
(September 2009-May 2011). For both sites

[[Page 66897]]

combined, only 41 hours of BW43 signal types were detected over a 
cumulative approximately five-and-a-half years of monitoring. The 41 
hours of BW43 detections therefore only represents a small fraction of 
overall recording time (less than 1 percent).
    The beaked whale signal type detected called BW43 has been 
suggested as coming from Perrin's beaked whales (Baumann-Pickering et 
al. 2014), but not yet conclusively and scientifically confirmed.
    A different Navy-funded single site south of San Clemente Island 
within the San Clemente Basin has had a passive acoustic device in 
place from July 2014 through current. [Scaron]irovi[cacute] et al. 
(2016) and Rice et al. (2017) contain the most current results from San 
Clemente Basin site ``N.'' While [Scaron]irovi[cacute] et al. (2016) 
and Rice et al. (2017) do report periodic passive acoustic detections 
of Mesoplodon beaked whales thought to be Perrin's beaked whale in San 
Clemente Basin, the overall detection rate, periodicity, and occurrence 
has not been high. Between May 2015 and June 2016, there were only 
seven weeks in which potential Perrin's beaked whale echolocation 
clicks were detected, with each week having less than 0.14 hours/week 
of detections. Acoustic sampling of bathymetrically featureless areas 
off Southern California with drifting hydrophones by NMFS detected many 
beaked whales over abyssal plains and not always associated with slope 
or seamount features, which counters a common misperception that beaked 
whales are primarily found over slope waters, in deep basins, or over 
seamounts (Griffins and Barlow 2016). One of these devices was deployed 
within the SOCAL portion of the HSTT Study Area. In addition, analysis 
of NMFS visual survey data from 2014, the most recent year available, 
showed an increase in Mesoplodon beaked whales along the entire U.S. 
West Coast, which the authors attributed to an influx of tropical 
species of Mesoplodon during the unusually warm water condition that 
year (Barlow 2016; Moore & Barlow 2017). Perrin's beaked whale, part of 
the Mesoplodon guild, could be part of these sightings. In summary, San 
Clemente Basin and Santa Catalina Basin with similar low passive 
acoustic detection rates are likely to be part of Perrin beaked whale's 
general distribution along the U.S. West Coast and in particular 
Southern California and Baja Mexico. This distribution is likely to be 
wide ranging for Perrin's beaked whales as a species and highly 
correlated to annual oceanographic conditions. Santa Catalina and San 
Clemente basins do have infrequent suspected Perrin's beaked whale 
passive acoustic detections from a limited number of devices, but these 
areas may not specifically represent unique high occurrence locations 
warranting geographic protection beyond existing Navy protective 
measures.
    The Navy has been training and testing in and around the Northern 
Catalina Basin and waters southeast of Santa Catalina Island with the 
same systems for over 40 years, and there is no evidence of any adverse 
impacts having occurred and no indications that Navy training and 
testing has had any adverse impacts on populations of beaked whales in 
Southern California. The main source of anthropogenic noise in the 
Catalina Basin and waters south of San Clemente Island are associated 
with commercial vessel traffic concentrated in the northbound and 
southbound lanes of the San Pedro Channel that runs next to Santa 
Catalina Island and leads to and from the ports of Los Angeles/Long 
Beach and other commercial traffic from San Diego and ports to the 
north and south of Southern California. These waters in and around 
Northern Catalina Basin and waters southeast of Santa Catalina Island 
are critical to the Navy's training and testing activities, and so it 
is not practicable to limit or reduce access or preclude activities 
within that water space in the SOCAL portion of the HSTT Study Area.
    The Santa Catalina Basin area and Perrin's beaked whales were 
addressed in Appendix K (Geographic Mitigation Assessment), Section 
K.7.2.3 (Catalina Basin) and K.7.2.7 (Northern Catalina Basin and the 
San Clemente Basin) of the HSTT FEIS/OEIS. Also see Appendix K 
(Geographic Mitigation Assessment), Section K.7.2.7.2 (Northern 
Catalina Basin and Waters Southeast of Catalina Island Perrin's Beaked 
Whale Habitat Mitigation Considerations) of the HSTT FEIS/OEIS for 
additional information regarding this species. Additional limitations 
as discussed in Appendix K (Geographic Mitigation Assessment) would 
limit training and impact readiness. Given that there is no evidence of 
impacts to the population of beaked whales in the area, and low 
potential occurrence of Perrin's beaked whales in the Southern 
California portion of the HSTT Study Area, geographic mitigation would 
not effectively balance a reduction of biological impacts with an 
acceptable level of impact on military readiness activities. As noted 
in Appendix K (Geographic Mitigation Assessment) and Chapter 5, Section 
5.3 (Procedural Mitigation to be Implemented) of the HSTT FEIS/OEIS, 
the Navy will continue to implement procedural mitigation measures 
throughout the HSTT Study Area.
    Comment 50: Commenters recommended additional mitigation areas for 
important fin whale habitat off Southern California. The commenters 
recommended that the waters between the 200 m and 1000 m isobaths be 
assessed for time-area management so that, at minimum, ship strike 
awareness measures for fin whales can be implemented during the months 
of November through February, when the whales aggregate in the area.
    Response: As described and detailed in the HSTT FEIS/OEIS, the Navy 
implements a number of ship-strike risk reduction measures for all 
vessels, in all locations and seasons, and for all marine mammal 
species. New research by [Scaron]irovi[cacute] et al. (2017) supports a 
hypothesis that between the Gulf of California and Southern California, 
there could be up to four distinct sub-populations based on fin whale 
call types, including a Southern California resident population. There 
is also evidence that there can be both sub-population shifts and 
overlap within Southern California ([Scaron]irovi[cacute] et al., 
2017). Scales et al. (2017) also postulated two Southern California 
sub-populations of fin whales based on satellite tagging and habitat 
modeling. Scales et al. (2017) stated that some fin whales may not 
follow the typical baleen whale migration paradigm, with some 
individuals found in both warm, shallow nearshore waters <500 m, and 
deeper cool waters over complex seafloor topographies. Collectively, 
the author's spatial habitat models with highest predicted occurrence 
for fin whales cover the entire core training and testing portion of 
the SOCAL portion of the HSTT Study Area, not just areas between 200 
and 1,000 m. Results from Navy-funded long-term satellite tagging of 
fin whales in Southern and Central California still shows some 
individual fin whales engage in wide-ranging movements along the U.S. 
West Coast, as well as large daily movements well within subareas (Mate 
et al., 2017). In support of further refining the science on Southern 
California fin whales, Falcone and Schorr (2014) examined fin whale 
movements through photo ID and short-to-medium term (days-to-several 
weeks) satellite tag tracking under funding from the Navy. The authors 
conducted small boat surveys from June 2010 through January 2014, 
approximately three-and-a-half years. Of interest in terms of the 
comment and the 200-1,000 m isobaths occurrence, more fin whale tag 
locations were reported off the Palos Verdes

[[Page 66898]]

Peninsula and off of the Los Angeles/Long Beach commercial shipping 
ports in fall, both areas north of and outside of the Navy's Southern 
California Range Complex. Compared to the above areas, there were not 
as many tag locations in the similar isobaths region off San Diego 
associated with the Navy range area. Falcone and Schorr (2014) did 
document an apparent inshore-offshore distribution between Winter-
Spring and Summer-Fall. Given the apparent resident nature of some fin 
whales in Southern California as discussed in Falcone and Schorr 
(2014), Scales et al. (2017), and [Scaron]irovi[cacute] et al. (2017), 
it remains uncertain if the inshore-offshore seasonal pattern as well 
as sub-population occurrence will persist into the future, or if fin 
whales will change distribution based on oceanographic impacts on 
available prey (ex. El Nino, climate change, etc.). The efforts from 
Falcone and Schorr on fin whales began in 2010 and are planned to 
continue for the next several years under Navy monitoring funding to 
further refine fin whale population structure and occurrence within 
Southern California.
    The data from the various single bottom-mounted passive acoustic 
devices used in the analysis are not continuous and have various 
periodicities for which data have been collected. Many of these devices 
are purposely placed in 200-1000 m of water. Given these are point 
sources of data, they may or may not be indicative of fin whale calling 
or presence at other locations within Southern California without 
devices. Passive acoustic analysis is only useful for those individuals 
that are calling and may not indicate total population occurrence. Low-
frequency fin whale calls by their very nature have relatively long 
underwater propagation ranges so detections at a single device could 
account for individuals 10-50 miles away if not further, depending on 
local propagation conditions. This would mean calling whales are not in 
the 200-1000 m area. [Scaron]irovi[cacute] et al. (2015) acknowledge in 
discussing their data biases, that their use of ``call index'' may best 
indicate a period of peak calling. But fin whales produce multiple call 
types depending on behavioral state. Based on technology limitations, 
some fin whale call types were not included in [Scaron]irovi[cacute] et 
al. (2015).
    1. The study cited by a commenter ([Scaron]irovi[cacute] et al., 
2015) and used as the basis for ``Figure 3'' concerns trends seen 
within the Southern California Bight, not exclusively the SOCAL Range 
Complex;
    2. The research used as the basis for Figure 3 was funded by the 
Navy to develop baseline information for the areas where Navy trains 
and tests and was by no means designed to or otherwise intended as a 
representative sample of all waters off California or the entire 
habitat of the fin whale population in the area;
    3. It is not correct to assume detected vocalizations (a ``call 
index'') reported in [Scaron]irovi[cacute] et al. (2015) for fin whales 
equates with where fin whales are aggregated in the Southern California 
Bight. For example, the acoustic monitoring data did not pick up or 
otherwise correspond to the observed seasonal distribution shift of fin 
whales indicated by visual survey data covering the same time periods 
(Campbell et al., 2015; Douglas et al., 2014);
    4. [Scaron]irovi[cacute] et al. (2015) make no such claim of 
aggregations during the winter months but instead compare call index 
rates and state that the purpose for the paper was to demonstrate that 
passive acoustics can be a powerful tool to monitor population trends, 
not relative abundances;
    5. There is no science to support the contention that fin whales 
are ``at particular risk of ship-strike on the naval range.'' Two fin 
whales were struck by the Navy in 2009 in the Southern California 
portion of the HSTT Study Area as Navy noted in Appendix K (Geographic 
Mitigation Assessment), but there have been no fin whales struck and in 
fact no whales of any species struck in the subsequent nine-year period 
despite a documented increase in the fin whale population inhabiting 
the area (Barlow, 2016; Moore & Barlow, 2011; Smultea & Jefferson, 
2014). Furthermore, one of those vessel strikes occurred at the end of 
the recommended mitigation timeframe (February) and the other well 
outside the time period (May), so the proposed mitigation would only 
have been marginally effective, if at all. Neither of these Navy fin 
whale strike locations were close to shore (both >50-60 Nmi from 
shore), or associated with coastal shipping lanes. Based on an analysis 
of Navy ship traffic in the HSTT Study Area between 2011 and 2015, 
median speed of all Navy vessels within Southern California is 
typically already low, with median speeds between 5 and 12 knots (CNA, 
2016). This includes areas within and outside of 200-1000 m within 
Southern California, with slowest speeds closer to the coast; and
    6. As presented in the EIS/OEIS, fin whales are present off all the 
waters of Southern California year-round ([Scaron]irovi[cacute] et al., 
2015, 2017). Using available quantitative density and distribution 
mapping, the best available science, and expert elicitation, definitive 
areas of importance for fin whales could not be determined by a panel 
of scientists specifically attempting to do so (Calambokidis et al., 
2015).
    Navy vessels already operate at a safe speed given a particular 
transit or activity need. This also includes a provision to avoid large 
whales by 500 yards, so long as safety of navigation and safety of 
operations is maintained. Previously, the Navy commissioned a vessel 
density and speed report for HSTT (CNA, 2016). Based on an analysis of 
Navy ship traffic in HSTT between 2011 and 2015, median speed of all 
Navy vessels within Southern California is typically already low, with 
median speeds between 5 and 12 knots (CNA, 2016). Slowest speeds 
occurred closer to the coast and islands.
    In conclusion, speed restrictions within 200-1000 m is unwarranted 
given the wide range of fin whale movements along the U.S. West Coast 
including areas within and outside of 200-1000 m contours, sometimes 
large-scale daily movements within regional areas as documented from 
Navy-funded satellite tagging, the current lack of ship strike risk 
from Navy vessels in Southern California (2010-2017), the already safe 
training and testing ship speeds Navy uses within HSTT, and existing 
Navy mitigation measures including provisions to avoid large whales by 
500 yards where safe to do so.
    In addition, the Navy agreed to send out seasonal awareness 
messages of blue, fin, and gray whale occurrence to improve awareness 
of all vessels operating to the presence of these species in SOCAL.

Hawaii Areas

    Comment 51: NPS recommends that the Navy consider the following as 
it plans to conduct activities in the HSTT Study Area. NPS notes units 
of the NPS system that occur near training and testing areas around 
Hawaii and identify which can be affected by noise. The Units are: 
Kaloko-Honokohau National Historical Park (NHP), Pu'uhonua o Honaunau 
NHP, Pu'ukolhola Heiau National Historic Site, Kalaupapa NHP, and the 
World War II Valor in the Pacific National Monument.
    Response: National Parks and Marine protected areas in are 
addressed in Chapter 6 of the HSTT FEIS/OEIS. Kalaupapa National 
Historical Park (NHP) is discussed in Comment 52 below. No planned 
activities overlap with Kaloko-Honokohau NHP; therefore, no impacts are 
expected within the Kalaupapa NHP. The Pu'uhonua o Honaunau NHP and 
Pu'ukolhola Heiau National Historic Site are not specifically addressed 
in Chapter 6 of

[[Page 66899]]

the FEIS/OEIS, but neither site appears to contain any marine waters. 
The Navy's planned activities do not occur on land except in designated 
training areas on Navy properties (i.e., for amphibious assaults, 
etc.); therefore, there are no activities that overlap with these sites 
and no impacts are expected. The WWII Valor in the Pacific Monument is 
for the USS Arizona which is a Navy war memorial. No activities occur 
within the boundary of the site itself, and the monument was not 
designated to protect marine species. There are training and testing 
activities that occur within Pearl Harbor as a whole, and impacts to 
marine mammals in the waters of Pearl Harbor as a whole were include in 
Navy's proposed activities and therefore analyzed by NMFS in this final 
rule.
    Comment 52: The NPS noted the presence of marine mammal species in 
the Kalaupapa NHP (on the north shore of Molokai), and is concerned 
about potential take of protected species that inhabit water out to 
1000 fathoms, and recommended the Navy consider alternate training 
areas to avoid impacts to these species. Species that occur year-round 
include the false killer whale, sperm whale, pygmy sperm whale, spinner 
dolphin, and bottlenose dolphin. Humpback whales are seasonal visitors 
from November to April. The Hawaiian monk seal pups are within the 
Kalaupapa NHP during the Spring and Summer.
    Response: Part of the Kalaupapa NHP (northern portion) is protected 
by the measures employed inside the 4-Islands Region Mitigation Area 
such as year-round prohibition on explosives and no use of MF1 surface 
ship hull mounted mid-frequency active sonar from November 15-April 
15).
    We note, however, that the majority of the Kalaupapa NHP is not in 
the 4-Islands Region Mitigation Area as it is mainly landbased, but 
just outside it. The Kalaupapa NHP was designated to protect the two 
historic leper colonies on the property and was not designated with the 
purpose of protecting marine species. The boundaries of the Kalaupapa 
NHP extend a quarter mile offshore. The Navy does propose conducting 
activities associated with the planned activities in the boundary of 
the the Kalaupapa NHP. There would be no effect to Hawaiian monk seal 
pupping on NHP land as the Navy does not have any planned activities in 
the boundary of the Kalaupapa NHP, especially on land. The Navy's 
planned activities do not include any land-based activities except for 
a few activities which are conducted on designated Navy property (i.e., 
amphibious assaults on Silver Strand, etc.). Further, as the seaspace 
adjacent to the Kalaupapa NHP is not an established training or testing 
area, it is unlikely naval activity would occur in this area.
    Comment 53: A commenter recommended expanding the Hawaii Island 
Mitigation Area westward to protect resident Cuvier's beaked whales and 
rough-toothed dolphins. The boundaries of the Hawaii Island Mitigation 
Area should be expanded westward to remain consistent with the 
boundaries of the BIAs defined in Baird et al. (2015), which informed 
the boundaries of Conservation Council Settlement Areas 1-C and 1-D. 
This expansion will cover habitat for Cuvier's beaked whales and 
toothed dolphins that are resident around the Big Island.
    Response: Analyses of the marine mammal species mentioned in the 
comment and considered within the Hawaii Island Mitigation Area are 
discussed throughout Appendix K (Geographic Mitigation Assessment), 
Section K.3 (Biologically Important Areas within the Hawaii Range 
Complex Portion of the HSTT Study Area) and Sections K.5.1 (Settlement 
Areas Within the Hawaii Portion of the HSTT Study Area) through K.5.4 
(Proposed Mitigation Areas that Overlap the Hawaii Portion of the HSTT 
Settlement Agreement Areas) of the HSTT FEIS/OEIS. Additional 
information on the marine mammals mentioned in the comment is also 
provided in the species-specific sub-sections in Chapter 3, Section 
3.7.2 (Affected Environment) of the HSTT FEIS/OEIS. Based on these 
analyses, the Navy will implement additional mitigation within the 
Hawaii Island Mitigation Area (year-round) as detailed in Chapter 5, 
Section 5.4.2 (Mitigation Areas for Marine Mammals in the Hawaii Range 
Complex) of the HSTT FEIS/OEIS, to further avoid or reduce impacts on 
marine mammals from acoustic and explosive stressors from the planned 
activities.
    The mitigation requirement of prohibiting the use of explosives 
year-round during training and testing across the entire Hawaii Island 
Mitigation Area satisfies the previous mitigation requirement of a 
prohibition on the use of in-water explosives for training and testing 
activities of the Settlement Agreement for Areas 1-A, 1-C, and 1-D, and 
further extends that requirement to the `Alenuih[amacr]h[amacr] Channel 
(Area 1-B). The Hawaii Island Mitigation Area still includes 100 
percent of Settlement Areas 1-C and 1-D and includes a large majority 
of the BIAs for Cuvier's Beaked Whale (Hawaii Island BIA) and Rough-
Toothed Dolphins (Hawaii Island BIA) (the areas in question by this 
comment). Particularly, it covers 93.30 percent of the Cuvier's Beaked 
Whale BIA westward of Hawaii Island and 83.58 percent of Rough-toothed 
dolphins Hawaii Island BIA westward of Hawaii Island.
    Only the northern portion of the Cuvier's beaked whale BIA in 
Alenuihaha Channel and a smaller offshore portion of the BIA west of 
Hawaii are not covered by mitigations included in the Hawaii Island 
Mitigation Area on the west and east of Hawaii Island. The BIAi s based 
on the known range of the island-associated population, and the authors 
suggest that ``the range of individuals from this population is likely 
to increase as additional satellite-tag data become available'' (Baird 
et al., 2015b). Cuvier's beaked whales are not expected to be displaced 
from their habitat due to training and testing activities further 
offshore in these small areas of the biologically important area, given 
that the biologically important area covers 23,583 km\2\, is unbroken 
and continuous surrounding the island, and the BIA likely 
underrepresents their range. The small portion of the BIA that does not 
overlap the Hawaii Island Mitigation Area is offshore, and according to 
the most recent stock assessment approximately 95 percent of all 
sighting locations were within 45 km of shore. Additionally, 
consequences to individuals or populations are not unknown. No PTS is 
estimated or authorized. A small numbers of TTS and Level B behavioral 
harassment takes for Cuvier's beaked whales are estimated across the 
entire Hawaii portion of the Study Area due to acoustic stressors. Most 
of the TTS and Level B behavioral harassment takes for Cuvier's beaked 
whales are associated with testing in the Hawaii Temporary Operating 
Area, impacting the pelagic population (see Figure 3.7-36 of the HSTT 
FEIS/OEIS). It is extremely unlikely that any modeled takes would be of 
individuals in this small portion of the BIA that extends outside the 
Hawaii Island Mitigation Area.
    Long-term and relatively comprehensive research has found no 
evidence of any apparent effects while documenting the continued 
existence of multiple small and resident populations of various species 
as well as long-term residency by individual beaked whales spanning the 
length of the current studies that exceed a decade. Further, the Navy 
has considered research showing that in specific contexts (such as 
associated with urban noise, commercial vessel traffic, eco-tourism, or 
whale watching, Chapter 3, Section 3.7.2.1.5.2 (Commercial Industries)) 
of

[[Page 66900]]

the HSTT FEIS/OEIS that chronic repeated displacement and foraging 
disruption of populations with residency or high site fidelity can 
result in population-level effects. As also detailed in the HSTT FEIS/
OEIS, however, the Navy training and testing activities do not equate 
with the types of disturbance in this body of research, nor do they 
rise to the level of chronic disturbance where such effects have been 
demonstrated because Navy activities are typically sporadic and 
dispersed. There is no evidence to suggest there have been any 
population-level effects in the waters around Oahu, Kauai, and Niihau 
or anywhere in the HSTT Study Area. In the waters around Oahu, Kauai, 
and Niihau, documented long-term residency by individuals and the 
existence of multiple small and resident populations are precisely 
where Navy training and testing have been occurring for decades, 
strongly suggesting a lack of significant impact to those individuals 
and populations from the continuation of Navy training and testing.
    Mark-recapture estimates derived from photographs of rough-toothed 
dolphins taken between 2003 and 2006 resulted in a small and resident 
population estimate of 198 around the island of Hawaii (Baird et al., 
2008), but those surveys were conducted primarily with 40 km of shore 
and may underestimate the population. Data do suggest high site 
fidelity and low population size for the island-associated population. 
There are no tagging data to provide information about the range of the 
island-associated population; the biologically important area is based 
on sighting locations and encompasses 7,175 km2. Generally, this 
species is typically found close to shore around oceanic islands. Only 
approximately half of the BIA offshore is not covered by the Hawaii 
Island Mitigation Area, where the BIA overlaps with special use 
airspace. Consequences to individuals or populations are not unknown. 
No PTS is estimated or authorized. Some TTS and Level B behavioral 
harassment takes due to acoustic stressors for this species across the 
entire HSTT Study Area (see Figure 3.7-66). Significant impacts on 
rough-toothed dolphin natural behaviors or abandonment due to training 
with sonar and other transducers are unlikely to occur within the small 
and resident population area. A few minor to moderate TTS or Level B 
behavioral harassment to an individual over the course of a year are 
unlikely to have any significant costs or long-term consequences for 
that individual, and nothing in the planned activities is expected to 
cause a ``catastrophic event.'' The Navy operating areas west of Hawaii 
Island are used commonly for larger events for a variety of reasons 
described further in Section K.3 (Biologically Important Areas Within 
the Hawaiian Range Complex Portion of the HSTT Study Area) (e.g., the 
relatively large group of seamounts in the open ocean offers 
challenging bathymetry in the open ocean far away from civilian vessel 
traffic and air lanes where ships, submarines, and aircraft are 
completely free to maneuver) and sonar may be used by a variety of 
platforms. Enlarging the Hawaii Island Mitigation Area is not 
anticipated to realistically reduce adverse impacts. Expanding the 
Hawaii Island Mitigation Area has a limited likelihood of further 
reducing impacts on marine mammal species or stocks and their habitat, 
while these open ocean operating areas for important for training and 
testing and, in consideration of these factors (and the broader least 
practicable adverse impact considerations discussed in the 
introduction), NMFS has determined that requiring this additional 
mitigation is not appropriate.
    Comment 54: A commenter recommended limiting MTEs to reduce 
cumulative exposure in the Hawaii Island Mitigation Area.
    Response: Prohibiting MTEs outright or spatially separating them 
within the Hawaii Island Mitigation Area (which includes the formerly 
named Planning Awareness Area) was proposed as additional mitigation to 
ensure that ``marine mammal populations with highly discrete site 
fidelity . . . are not exposed to MTEs within a single year.'' The goal 
of geographic mitigation is not to be an absolute, outright barrier and 
stop exposing animals to exercises per se; it is to reduce adverse 
impacts to the maximum extent practicable. Impacts associated with 
major training exercises, including cumulative impacts, are addressed 
in Chapters 3 (Affected Environment and Environmental Consequences) and 
Chapter 4 (Cumulative Impacts) of the HSTT FEIS/OEIS, and Navy 
quantitative analysis using the best available science has determined 
that training and testing activities will not have population-level 
impacts on any species. As determined in Chapter 3, Section 3.7.4 
(Summary of Potential Impacts on Marine Mammals) of the HSTT FEIS/OEIS, 
it is not anticipated that the Proposed Action will result in 
significant impacts to marine mammals. To date, the findings from 
research and monitoring and the regulatory conclusions from previous 
analyses by NMFS are that the majority of impacts from Navy training 
and testing activities are not expected to have deleterious impacts on 
the fitness of any individuals or long-term consequences to populations 
of marine mammals.
    MTEs cannot be moved around within the Hawaii Island Mitigation 
Area, given that those activities are specifically located to leverage 
particular features like the Alenuihaha Channel and the approaches to 
Kawaihae Harbor. This recommendation is not, therefore, appropriate in 
consideration of NMFS' least practicable adverse impact standard.
    To limit activities, the Navy will not conduct more than 300 hours 
of MF1 surface ship hull-mounted mid-frequency active sonar or 20 hours 
of MF4 dipping sonar, or use explosives that could potentially result 
in takes of marine mammals during training and testing in the Hawaii 
Mitigation Area.
    Comment 55: A commenter recommended prohibiting or restricting 
other sources of mid-frequency active sonar in the Hawaii Island 
Mitigation Area including prohibiting the use of helicopter-deployed 
mid-frequency active sonar in the Hawaii Island Mitigation Area.
    Response: The Navy is already limiting other sources of MFAS. 
Between the application and the proposed rule, the Navy added new 
mitigation that includes a limit to the annual use of helicopter 
dipping sonar in the Hawaii Island Mitigation Area. Specifically, the 
Navy will not conduct more than 20 hours of MF4 dipping sonar that 
could potentially result in takes of marine mammals during training and 
testing. Helicopters deploy MFAS from a hover position in bouts 
generally lasting under 20 minutes, moving rapidly between sequential 
deployment and their duration of use and source level (217 dB) are 
generally well below those of hull-mounted frequency sonar (235 dB). 
All locations within the HSTT Study Area have been used for Navy 
training and testing for decades. There has been no scientific evidence 
to indicate the Navy's activities are having adverse effects on 
populations of marine mammals, many of which continue to increase in 
number or are maintaining populations based on what regional conditions 
can support. Navy research and monitoring funding continues within the 
HSTT Study Area under current NMFS MMPA and ESA permits, and is planned 
through the duration of any future permits. Given the lack of effects 
to marine mammal populations in the HSTT Study Area from larger, more 
powerful surface ship sonars, the effects from intermittent, less

[[Page 66901]]

frequent use of lower powered mid-frequency dipping sonar or other mid-
frequency active sonars would also not significantly affect small and 
resident populations.
    Comment 56: A commenter recommended extending the 4-Islands Region 
Mitigation Area westward to encompass the Humpback Whale Special 
Reporting Area in Kaiwi Channel. Additionally the 4-Island Region 
Mitigation Area is inadequate to protect endangered Main Hawaiian 
Island insular false killer whales as the Main Hawaiian Island insular 
false killer whale is highly range-restricted to certain high-use 
areas, one of which includes the ESA critical habitat and the BIA north 
of Maui and Molokai (``False killer whale Hawaii Island to Niihau'' 
BIA).
    Response: The portion of the special reporting area that extends 
into Kaiwi Channel over Penguin Bank (equivalent to settlement area 2A) 
is generally not a higher use area for Main Hawaiian Island insular 
false killer whales and does not overlap significantly with the 
biologically important area. As presented in Chapter 3 (Affected 
Environment and Environmental Consequences), Navy quantitative analysis 
indicates that significant impacts on false killer whale natural 
behaviors or abandonment due to training with sonar and other 
transducers are unlikely to occur within the entire small and resident 
population area, let alone in the small sub-portion of the biologically 
important area that overlaps the proposed extension. Additionally, most 
of the modeled takes are for the Hawaii pelagic population of false 
killer whale (see Figure 3.7-46 and Table 3.7-31). Also, as described 
in more detail in Appendix K of the HSTT FEIS/OEIS, due to training and 
testing needs, the expansion of this area is considered impracticable.
    Comment 57: A commenter recommended extending to year-round 
restrictions in the 4-Island Region Mitigation Area and the proposed 
extension into the Kaiwi Channel Humpback Whale Special Reporting Area.
    Response: The additional expansion requested in the comment is not 
expected to reduce adverse impacts to an extent that would outweigh the 
negative impacts if unit commanders were unable to conduct unit-level 
training and testing, especially as they pass over Penguin Bank while 
transiting between Pearl Harbor and other parts of the Study Area. 
Prohibiting mid-frequency active sonar would preclude the Submarine 
Command Course from meeting its objectives and leveraging the important 
and unique characteristics of the 4-Islands Region, as described in 
multiple sections of Appendix K (e.g., Section K.3.1.6 (4-Islands 
Region and Penguin Bank Humpback Whale Reproduction Area, and 
Settlement Area 2-A and 2-B)). Penguin Bank is particularly used for 
shallow water submarine testing and anti-submarine warfare training 
because of its large expanse of shallow bathymetry. The conditions in 
Penguin Bank offer ideal bathymetric and oceanographic conditions 
allowing for realistic training and testing and serve as surrogate 
environments for active theater locations.
    Additionally, this mitigation would further increase reporting 
requirements. As discussed in Chapter 5 (Mitigation) Section 5.5.2.6 
(Increasing Reporting Requirements) of the HSTT FEIS/OEIS, the Navy 
developed its reporting requirements in conjunction with NMFS, 
balancing the usefulness of the information to be collected with the 
practicability of collecting it. An increase in reporting requirements 
as a mitigation would draw the event participants' attentions away from 
the complex tactical tasks they are primarily obligated to perform 
(such as driving a warship), which would adversely impact personnel 
safety, public health and safety, and the effectiveness of the military 
readiness activity. Expanding the Mitigation Area and extending the 
restrictions is not, therefore, appropriate in consideration of NMFS' 
least practicable adverse impact standard.
    Comment 58: A commenter recommended implementing vessel speed 
restrictions within the 4-Islands Region Mitigation Area.
    Response: This mitigation measure was proposed to address impacts 
on humpback whales due to both ship noise and ship strikes. As 
described and detailed in the Draft EIS, the Navy already implements a 
number of ship-strike risk reduction measures for all vessels, in all 
locations and seasons, and for all marine mammal species. The Navy 
cannot implement mitigation that restricts vessel speed during training 
or testing in the HSTT Study Area. Vessels must be able to maneuver 
freely as required by their tactics in order for training events to be 
effective. Imposition of vessel speed restrictions would interfere with 
the Navy's ability to complete tests that must occur in specific 
bathymetric and oceanic conditions and at specific speeds. Navy vessel 
operators must test and train with vessels in such a manner that 
ensures their ability to operate vessels as they would in military 
missions and combat operations (including being able to react to 
changing tactical situations and evaluate system capabilities). 
Furthermore, testing of new platforms requires testing at the full 
range of propulsion capabilities and is required to ensure the 
delivered platform meets requirements. Based on an analysis of Navy 
ship traffic in the HSTT Study Area between 2011 and 2015, median speed 
of all Navy vessels within Hawaii is typically already low, with median 
speeds between 8-16 kn (CNA, 2016). Speed restrictions in the 
Cautionary Area (renamed the 4-Islands Region Mitigation Area) are 
unwarranted given the movement of all social groups throughout the 
islands outside the Mitigation Area, the current lack of ship strike 
risk from Navy vessels in Hawaii (2010-2017), the already safe training 
and testing ship speeds the Navy uses within HSTT, and existing Navy 
mitigation measures, including provisions to avoid large whales by 500 
yards where safe to do so. Implementing speed restrictions in the 
Mitigation Area is not, therefore, appropriate in consideration of 
NMFS' least practicable adverse impact standard.
    Information on the response of baleen whales to vessel noise is 
presented in Section 3.7.3.1.1.5 (Behavioral Reactions) and Section 
3.7.3.1.5 (Impacts from Vessel Noise). Impacts, if they did occur, 
would most likely be short-term masking and minor behavioral responses. 
Therefore, significant impacts on humpback whale reproductive behaviors 
from vessel noise associated with training activities are not expected. 
Navy vessels are intentionally designed to be quieter than civilian 
vessels, and ship speed reductions are not expected to reduce adverse 
impacts on humpback whales due to vessel noise.
    Comment 59: A commenter recommended prohibiting the use of in-water 
explosives in the 4-Islands Region Mitigation Area.
    Response: The Navy has agreed to implement a year-round restriction 
on the use of in-water explosives that could potentially result in 
takes of marine mammals during training and testing. Should national 
security present a requirement explosives that could potentially result 
in the take of marine mammals during training or testing, naval units 
will obtain permission from the appropriate designated Command 
authority prior to commencement of the activity. The Navy will provide 
NMFS with advance notification and include the information (e.g., sonar 
hours or explosives usage) in its annual activity reports submitted to 
NMFS.
    Comment 60: A commenter recommended prohibiting other sources

[[Page 66902]]

of MFAS in the 4-Islands Region Mitigation Area.
    Response: NMFS reviewed Navy's assessment for the 4-Islands 
Mitigation Area. This area provides a unique and irreplaceable shallow 
water training capability for units to practice operations in littoral 
areas that are both shallow and navigationally constrained (HSTT FEIS 
Appendix K (Geographic Mitigation Assessment), Section K.3.3.1.6). The 
4-Islands Region provides an environment for anti-submarine warfare 
search, tracking and avoidance of opposing anti-submarine warfare 
forces. The bathymetry provides unique attributes and unmatched 
opportunity to train in searching for submarines in shallow water. 
Littoral training allows units to continue to deploy improved sensors 
or tactics in littoral waters. In the Hawaii portion of the HSTT Study 
Area specifically, anti-submarine warfare training in shallow water is 
vitally important to the Navy since diesel submarines typically hide in 
that extremely noisy and complex marine environment (Arabian Gulf, 
Strait of Malacca, Sea of Japan, and the Yellow Sea all contain water 
less than 200 m deep). There is no other area in this portion of the 
HSTT Study Area with the bathymetry and sound propagation analog to 
seas where Navy conducts real operations that this training could 
relocate to. The Navy cannot conduct realistic shallow water training 
exercises without training in and around the 4-Islands Region 
Mitigation Area. In addition, this area includes unique shallow water 
training opportunities for unit-level training, including opportunity 
to practice operations in littoral areas that are both shallow, and 
navigationally constrained, and in close proximity to deeper open ocean 
environments. While MFAS is used infrequently in this area, a complete 
prohibition of all active sonars would impact Navy training readiness 
in an area identified as important for the Navy based on its unique 
bathymetry. However, the Navy recognizes the biological importance of 
this area to humpback whales during the reproductive season and with 
NMFS concurrence strives to limit the use of surface ship hull-mounted 
MFAS during that time of year. While the Navy has been training and 
testing in the area with the same basic systems for over 40 years, 
there is no evidence of any adverse impacts having occurred, and there 
are multiple lines of evidence demonstrating the small odontocete 
population high site fidelity to the area.
    Comment 61: A commenter recommended prohibiting the use of 
helicopter-deployed mid-frequency active sonar in the 4-Islands Region 
Mitigation Area.
    Response: The commenter's request to prohibit ``air-deployed'' mid-
frequency active sonar is based on one paper (Falcone et al., 2017), 
which is a Navy-funded project designed to study the behavioral 
responses of a single species, Cuvier's beaked whales, to mid-frequency 
active sonar. The Navy relied upon the best science that was available 
to develop behavioral response functions for beaked whales and other 
marine mammals in consultation with NMFS for the Draft EIS/OEIS. The 
article cited in the comment (Falcone et al., 2017) was not available 
at the time the Draft EIS/OEIS was published but does not change the 
current FEIS/OEIS criteria or conclusions. The new information and data 
presented in the article was thoroughly reviewed when it became 
available and further considered in discussions with some of the 
paper's authors following its first presentation in October 2017 at a 
recent scientific conference. Many of the variables requiring further 
analysis for beaked whales and dipping sonar impact assessment are 
still being researched under continued Navy funding through 2019.
    There are no beaked whale biologically important areas in the 4-
Islands Region Mitigation Area, and the Mitigation Area is generally 
shallower than beaked whales' preferred habitat. Behavioral responses 
of beaked whales from dipping and other sonars cannot be universally 
applied to other marine mammal species. Research indicates that there 
are distinct individual variations as well as strong behavioral state 
considerations that influence any response or lack of response 
(Goldbogen et al., 2013; Harris et al., 2017). Therefore, it is 
expected that other species would have highly variable individual 
responses ranging from some response to no response to any 
anthropogenic sound. This variability is accounted for in the Navy's 
current behavioral response curves described in the HSTT Draft EIS/OEIS 
and supporting technical reports.
    Furthermore, the potential effects of dipping sonar have been 
rigorously accounted for in the Navy's analysis. Parameters such as 
power level and propagation range for typical dipping sonar use are 
factored into HSTT acoustic impact analysis along with guild specific 
criteria and other modeling variables, as detailed in the HSTT DEIS/
OEIS and associated technical reports for criteria and acoustic 
modeling. Further, due to lower power settings for dipping sonar, 
potential impact ranges of dipping sonar are significantly lower than 
surface ship sonars. For example, the HSTT average modeled range to TTS 
of dipping sonar for a 1-second ping on low-frequency cetacean (i.e., 
blue whale) is 77 m, and for mid-frequency cetaceans including beaked 
whales is 22 m (HSTT FEIS/OEIS Table 3.7-7). This range is easily 
monitored for marine mammals by a hovering helicopter and is accounted 
for in the Navy's proposed mitigation ranges for dipping sonars (200 
yds. or 183 m). Limited ping time (i.e., less dipping sonar use as 
compared to typical surface ship sonar use) and lower power settings 
therefore would limit the impact from dipping sonar to any marine 
mammal species.
    This is an area of extremely low use for air-deployed mid-frequency 
active sonar. Prohibiting air-deployed mid-frequency active sonar in 
the Mitigation Area would not be any more protective to marine mammal 
populations generally, or the Main Hawaiian Islands insular false 
killer whale in particular, than currently implemented procedural 
mitigation measures for air-deployed mid-frequency active sonar and is 
not, therefore, appropriate in consideration of NMFS' least practicable 
adverse impact standard.
    Comment 62: A commenter recommended prohibiting use of low-
frequency active sonar in the 4-Islands Region Mitigation Area.
    Response: The commenters suggested that ``Baleen whales are 
vulnerable to the impacts of low-frequency active sonar, particularly 
in calving areas where low-amplitude communication calls between 
mothers and calves can be easily masked.'' As described in Chapter 3, 
Section 3.7.2.3.1 (Humpback Whale (Megaptera novaeangliae), Hawaii DPS) 
of the HSTT FEIS/OEIS, the best available science has demonstrated 
humpback whale population increases and an estimated abundance greater 
than some pre-whaling estimates. This data does not indicate any 
population-level impacts from decades of ongoing Navy training and 
testing in the Hawaiian Islands.
    Comment 63: A commenter recommended additional mitigation areas 
critical habitat for the Main Hawaiian Islands insular false killer 
whale. NMFS issued the Final Rule designating critical habitat under 
the ESA on July 24, 2018. A commenter stated that in light of the 2018 
listing under the ESA, NMFS must protect this species from the noise 
and other disturbance resulting from naval activities, including by 
mitigating impacts within its critical habitat. The commenter 
recommended that, at minimum, the Navy establish protective

[[Page 66903]]

Mitigation Areas in all the BIAs identified for this species by NOAA 
and that NMFS should revisit and revise its Mitigation Areas and 
mitigation requirements based on the final critical habitat 
designation.
    Response: Critical habitat includes waters from the 45 m depth 
contour to the 3,200 m depth contour around the main Hawaiian Islands 
from Niihau east to Hawaii (82 FR 51186). With regard to the analysis 
of the identified Biologically Important Areas for the Main Hawaiian 
Islands insular false killer whales, see Section K.3.3 (False Killer 
Whale Small and Resident Population Area: Main Hawaiian Island Insular 
stock). With regard to the identified threats to the species, see 
Section 3.7.2.2.7.5 (Species-Specific Threats) and specifically the 
documented incidental take by commercial fisheries (Bradford and 
Forney, 2016; Oleson et al., 2010; Reeves et al., 2009; West, 2016). 
NMFS has previously determined that Navy's current training and testing 
activities are not expected to have fitness consequences for individual 
Main Hawaiian Islands insular false killer whales and not likely to 
reduce the viability of the populations those individual whales 
represent.
    The Navy is implementing the Hawaii Island Mitigation Area which 
encompassess all of the BIA for Main Hawaiian Islands insular false 
killer whales around that island, and the 4-Islands Region Mitigation 
Area (which captures approximately 40 percent of the BIAs in the 4-
island area). As discussed in the Mitigation Areas in Hawaii section of 
this final rule, these mitigation areas are expected to significantly 
reduce impacts to this stock and its habitat.
    Comment 64: Commenters recommended additional mitigation areas for 
important habitat areas off Oahu, Kauai, and Niihau--the waters off 
Oahu, Kauai, and Niihau include a number of important habitat areas for 
a variety of species, including false killer whale critical habitat 
(see above), five NOAA-identified BIAs off Oahu (false killer whale, 
humpback whale, pantropical spotted dolphin, bottlenose dolphin, and 
spinner dolphin) and three BIAs off Kauai and Niihau (humpback whale, 
spinner dolphin, and bottlenose dolphin) (Baird et al. 2012). The 
commenters assert that the agency must consider the implementation of 
Mitigation Areas off Oahu, Kau`i, and Niihau. Providing mitigation 
measures for select activities during even a limited season within some 
important habitat areas.
    Response: In the HSTT FEIS/OEIS, the Navy considered the science, 
the Navy requirements, and the effectiveness of identified habitat 
areas off Oahu, Kauai, and Niihau as presented in Appendix K 
(Geographic Mitigation Assessment) Section K.3 (Biologically Important 
Areas within the Hawaii Range Complex Portion of the HSTT Study Area). 
This includes the five identified Biologically Important Areas off Oahu 
(false killer whale, humpback whale, pantropical spotted dolphin, 
bottlenose dolphin, and spinner dolphin) and three Biologically 
Important Areas off Kauai and Niihau (humpback whale, spinner dolphin, 
and bottlenose dolphin) as well as a discussion in Appendix K 
(Geographic Mitigation Assessment), Section K.1.1.5 (Mitigation Areas 
Currently Implemented) regarding the 4-Islands Region Mitigation Area.
    Based on the Navy's analysis and as detailed in the sections 
referenced above, there is no scientific basis indicating the need for 
mitigation in the first place; see specifically the discussion in 
Appendix K (Geographic Mitigation Assessment), Section K.2.1.2 
(Biological Effectiveness Assessment) of the HSTT FEIS/OEIS. As 
presented and reviewed in the HSTT FEIS/OEIS, the Navy has presented 
citations to research showing that in specific contexts (such as 
associated with urban noise, commercial vessel traffic, eco-tourism, or 
whale watching; see Chapter 3,Section 3.7.2.1.5.2 (Commercial 
Industries)) and references (Dunlop, 2016; Dyndo et al., 2015; Erbe et 
al., 2014; Frisk, 2012; Gedamke et al., 2016; Hermannsen et al., 2014; 
Li et al., 2015; McKenna et al., 2012; Melc[oacute]n et al., 2012; 
Miksis-Olds and Nichols, 2015; Nowacek et al., 2015; Pine et al., 2016; 
Pirotta et al. 2018; Williams et al., 2014c) or specifically for Hawaii 
(Heenehan et al., 2016a, 2016b; Heenehan et al., 2017a, 2017b; Tyne et 
al., 2014; Tyne, 2015; Tyne et al., 2015; Tyne et al., 2017), that 
chronic repeated displacement and foraging disruption of populations 
with residency or high site fidelity can result in population-level 
effects. As also detailed in the HSTT FEIS/OEIS, the planned Navy 
training and testing activities do not equate with the types of 
disturbance in the citations above nor do they rise to the level of 
chronic disturbance where such effects have been demonstrated. There is 
no evidence to suggest there have been any population-level effects in 
the waters around Oahu, Kauai, and Niihau or in the HSTT Study Area 
resulting from the same training and testing activities that have been 
ongoing for decades, which the commenter recommends the need to stop, 
or at a minimum, be mitigated. In the waters around Oahu, Kauai, and 
Niihau, documented long-term residency by individuals and the existence 
of multiple small and resident populations precisely where Navy 
training and testing have been occurring for decades strongly suggests 
a lack of significant impact to those individuals and populations from 
the continuation of Navy training and testing. Appendix K of the HSTT 
FEIS/OEIS further describes the importance of these areas for Navy 
training and testing and why implementation of additional mitigation 
areas would be impracticable.
    Comment 65: A commenter recommended additional mitigation area for 
Cross Seamount, as Cross Seamount represents important foraging habitat 
for a potentially rare or evolutionary distinct species of beaked 
whale, a commenter strongly recommended that the HSTT EIS/OEIS assess 
the designation of a year-round management area to protect the 
seamount. Such a designation would have secondary benefits for a 
variety of other odontocete species foraging at Cross Seamount 
seasonally between November and May. NMFS should also consider habitat-
based management measures for other nearby seamounts.
    Response: Analysis and consideration of Cross Seamount and ``other 
nearby seamounts'' for additional geographic mitigation was provided in 
Appendix K (Geographic Mitigation Assessment), Section K.7.1 (Hawaii 
Public Comment Mitigation Area Assessment), including sub-sections 
K.7.1.1 (General Biological Assessment of Seamounts in the Hawaii 
Portion of the Study Area) and K.7.1.2 (Cross Seamount) of the HSTT 
FEIS/OEIS.
    As discussed in Appendix K (Geographic Mitigation Assessment), 
Section 4.7.1.3 (Mitigation Assessment) of the HSTT FEIS/OEIS, 
implementing new geographic mitigation measures in addition to ongoing 
procedural mitigation within the vicinity of Cross Seamount would not 
be effective at reducing adverse impacts on beaked whales or other 
marine mammal populations. The Navy has been training and testing in 
the broad ocean area around Cross Seamount with the same basic systems 
for over 40 years, and there is no evidence of any adverse impacts to 
marine species. Additionally, the suggested mitigation would not be 
practicable to implement. The broad ocean area around Cross Seamount 
and the seamounts to the north are unique in that there are no similar 
broad ocean areas in the vicinity of the Hawaiian Islands that are not 
otherwise

[[Page 66904]]

encumbered by commercial vessel traffic and commercial air traffic 
routes. In addition, beaked whales may be more widely distributed than 
currently believed. Ongoing passive acoustic efforts from NMFS and Navy 
within the Pacific have documented beaked whale detections at many 
locations beyond slopes and seamounts to include areas over abyssal 
plains (Klinck et al. 2015, Griffiths and Barlow 2016, Rice et al., 
2018).
    Comment 66: A commenter commented that the NMFS must ensure that 
the activities are having the least practicable adverse impact, so it 
must do a comprehensive analysis of whether the proposed mitigation 
areas sufficiently protect marine mammals. NMFS must require the Navy 
to implement additional, practicable measures to mitigate further the 
adverse impacts of its activities. To ensure least practicable adverse 
impacts, NMFS must consider additional mitigation time/area 
restrictions, including but not limited to: (1) Expanded areas in 
Southern California to include all of the biologically important areas 
for whales; (2) add a Cuvier's beaked whale mitigation area in Southern 
California to protect that small, declining population that has high 
site fidelity; (3) add mitigation areas for the biologically important 
areas off of Oahu and Kauai; (4) the entire Humpback National Marine 
Sanctuary should be afforded protections from Navy activities because 
it is an important habitat for breeding, calving and nursing; and (5) 
limits on sonar and explosives should be adopted in the designated 
critical habitat for the Hawaiian monk seal and false killer whale.
    Response: In regards to expanded areas in Southern California to 
include all of the biologically important areas for whales, the Navy 
has agreed to expanded areas in SOCAL, a portion of the San Nicholas 
Island BIA and the Santa Monica/Long Beach BIA are now included as part 
of the San Diego Arc Mitigation Area but also named the San Nicholas 
Island Mitigation Area and the Santa Monica/Long Beach Mitigation Area. 
The Santa Monica Bay/Long Beach and San Nicolas Island BIA only 
partially overlaps a small portion of the northern part of the SOCAL 
portion of the HSTT Study Area. The Santa Monica Bay/Long Beach BIA 
overlap in SOCAL is 13.9 percent. The San Nicolas Island BIA overlap in 
SOCAL is 23.5 percent.
    The Navy will limit surface ship sonar and not exceed 200 hours of 
MFAS sensor MF1 June 1 through October 31 during unit-level training 
and MTEs in the Santa Monica Bay/Long Beach BIA and San Nicolas Island 
Mitigation Areas (as well as San Diego Arc Mitigation Area). The Navy 
has also agreed to limit explosives. Specifically, within the San 
Nicolas Island Mitigation Area, the Navy will not use explosives that 
could potentially result in the take of marine mammals during mine 
warfare, large-caliber gunnery, torpedo, bombing, and missile 
(including 2.75'' rockets) activities during training. Within the Santa 
Monica/Long Beach Mitigation Area, the Navy will not use explosives 
that could potentially result in the take of marine mammals during mine 
warfare, large-caliber gunnery, torpedo, bombing, and missile 
(including 2.75'' rockets) activities during training and testing.
    The Tanner-Cortes Bank BIA--NMFS and the Navy have discussed this 
extensively, and the Navy is unable to incorporate this area into 
geographic mitigation because is impracticable. Specifically, it would 
not be practical for the Navy to implement and prevents the Navy from 
meeting training and testing missions. As discussed in detail in 
Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS, 
during the Navy's practicability and biological review of the Tanner 
Bank BIA, it was concluded that implementation of a mitigation area was 
not practical for this species. The area in and around Tanner Banks is 
a core high priority training and testing venue for SOCAL combining 
unique bathymetry and existing infrastructure. This includes an 
existing bottom training minefield adjacent to Tanner Banks, future 
Shallow Water Training Range (SWTR West) expansion as well as proximity 
to critical tactical maneuver areas to the south and the Navy's 
underwater instrumented range to the northeast. Furthermore, the 
general area is in or adjacent to critical Navy training that cannot 
occur at other locations due to available, existing infrastructure, 
operationally relevant bathymetry, sea space, proximity to San Clemente 
Island and San Diego, etc.). Of all the blue whale BIAs designated, the 
Tanner Banks BIA had the fewest blue whale sighting records supporting 
its designation. New science since designation funded by the Navy 
further highlights how infrequently Tanner Bank is used by blue whales 
as compared to the rest of their movements in SOCAL. Out of 73 blue 
whales tagged with satellite transmitters, only a few transits through 
Tanner Banks were documented between 2014-2017. The longest cumulative 
time any individual whale stayed within the boundaries of the Tanner 
Banks BIA was less than one and a half days. Typical average blue whale 
daily movement along the U.S. West Coast is often up to 13-27 nautical 
miles a day (Oregon State University, unpublished data). Most blue 
whale area restricted foraging occurred around the northern Channel 
Islands, north of and outside of the HSTT SOCAL Study Area.
    The feeding areas as recommended by the commenter north of Los 
Angeles for humpbacks (Santa Barbara Channel-San Miguel BIA and Morro 
Bay to Pt Sal) and blue whales (Santa Barbara Channel to San Miguel 
BIA, Pt Conception/Arguello to Pt Sal) are outside of the HSTT Study 
Area; therefore are not applicable for inclusion.
    In regard to adding a Cuvier's beaked whale mitigation area in 
Southern California to protect that small, declining population that 
has high site fidelity, NMFS is assuming the commenter is referring to 
the area west of San Clemente Island as the comment letter did not 
specify an exact location. The beaked whale species detected most 
frequently in Southern California is Cuvier's beaked whale. Cuvier's 
beaked whales are widely distributed within Southern California and 
across the Pacific with almost all suitable deep water habitat >800 m 
conceivably containing Cuvier's beaked whales. In new unpublished Navy 
funded data, beaked whales have even been detected over deep water, 
open abyssal plains (>14,000 feet). Only limited population vital rates 
exist for beaked whales, covering numbers of animals, populations vs. 
subpopulations determination, and residency time for individual 
animals. While Cuvier's beaked whales have been detected north and west 
of Tanner and Cortes Banks, as noted above this species is also 
detected in most all Southern California locations 800 m in depth. The 
Navy's Marine Mammal Monitoring on Navy Ranges (M3R) program has 
documented continual Cuvier's beaked whale presence on SOAR over 8-
years from 2010-2017 with slight abundance increases through 2017 
(DiMarzio et al., 2018.)
    Navy-funded research on Cuvier's beaked whales within the Southern 
California (SOCAL) Range Complex began in 2006. In 2008, researchers 
began deploying satellite tags as a part of this research. To date, 27 
Low- Impact Minimally-Percutaneous External-electronics Transmitting 
(LIMPET) tags have been deployed within the complex. Twenty-five of 
those whales were tagged within the San Nicolas Basin and two were 
tagged in the Catalina Basin. Average transmission duration was 36.6 
days (sd

[[Page 66905]]

= 29.8), with the longest transmitting for 121.3 days. Movement data 
suggest that Cuvier's beaked whales have a high degree of site-fidelity 
to the Southern California Range Complex, and the San Nicolas basin in 
particular. Overall, there were 3,207 filtered location estimates from 
the 27 tagged whales, 91 percent of which were within the SoCal Range 
Complex. 54 percent of all location estimates were within the San 
Nicolas Basin, with twelve tagged whales spending more than 80 percent 
of their transmission duration within the basin. The two whales tagged 
in the Catalina Basin never entered the San Nicolas Basin. Only three 
whales tagged in the San Nicolas Basin crossed into the Catalina Basin 
(1.3 percent of all locations); two of those whales had just one 
Catalina Basin location each, though the remaining whale had 28 percent 
of its locations there. Five whales tagged in the San Nicolas Basin 
moved into the Santa Cruz Basin for anywhere from 1-62 percent of their 
time (6 percent of all locations). In contrast, 20 of 25 whales tagged 
in the San Nicolas Basin moved south of the basin at some point. Of 
these 20 whales, most remained within either Tanner Canyon or the San 
Clemente Basin immediately to the south, but one traveled north to near 
San Miguel Island and four traveled south towards Guadalupe Island. 
Three of these whales have not been documented in the San Nicolas basin 
since, though to date at least six whales tagged in the San Nicolas 
Basin have been re-sighted there a year or more after the deployment. 
Additionally, one of the whales that was south of San Nicolas when the 
tag stopped transmitting has since been sighted three times since.
    Given that there is the uncertainty of current residence of 
Cuvier's beaked whales in the areas north and west of SOAR, the fact 
that general occurrence of beaked whales in Southern California may not 
necessarily equate to factors typically associated with biologically 
important areas (i.e., one area not more important than another), and 
consideration of the importance of Navy training and testing in the 
areas around SOAR and Tanner and Cortes Banks as discussed in Appendix 
K (Geographic Mitigation Assessment), i.e., the impracticability of 
additional area mitigation in this area, additional geographic 
mitigation to create a ``refuge'' in the recommended area is not 
scientifically supported or warranted.
    In regard to the comment on the entire Humpback Whale National 
Marine Sanctuary should be afforded protections from Navy activities 
because it is an important habitat for breeding, calving and nursing 
the Humpback National Marine Sanctuary largely overlaps both the Hawaii 
Island Mitigation Area as well as the 4-Islands Region Mitigation Area. 
In the Hawaii Island Mitigation Area (year-round), the Navy will not 
conduct more than 300 hours of MF1 surface ship hull-mounted mid-
frequency active sonar or 20 hours of MF4 dipping sonar, or use 
explosives that could potentially result in takes of marine mammals 
during training and testing. In the 4-Islands Region Mitigation Area 
(November 15-April 15 for active sonar; year-round for explosives), the 
Navy will not use MF1 surface ship hull-mounted mid-frequency active 
sonar or explosives that could potentially result in takes of marine 
mammals during training and testing. This seasonal limitation is 
specifically during important breeding, calving, and nursing, times/
habitat for humpback whales and was expanded for humpback whales as the 
previous season for this mitigation area was December 15-April 15).
    There are areas of the Humpback Whale National Marine Sanctuary 
around the islands of Niihau, Kauai, Oahu, and west of Molokai (Penguin 
Bank) that are outside of the Navy's mitigation areas. However, none of 
the Navy's training and testing areas for explosives around Kauai and 
Niihau are within the Hawaiian Islands Humpback Whale National Marine 
Sanctuary. There may be limited sonar use as units transit to/from PMRF 
ranges.
    Part of the Humpback Whale National Marine Sanctuary, west of the 
island of Molokai, Penguin Bank, is not included in the 4-Islands 
Region Mitigation Area. Penguin Bank particularly is used for shallow 
water submarine testing and anti-submarine warfare training because of 
its large expanse of shallow bathymetry. While submarines do not 
typically use mid-frequency active sonar, relying primarily on passive 
sonar (listening mode) to avoid detection from adversaries, submarines 
are required to train in counter detection tactics, techniques and 
procedures against threat surface vessels, airborne anti-submarine 
warfare units and other threat submarines using mid-frequency active 
sonar as part of both their perspective Commanding Officers 
qualification course and pre-deployment certification. The ability for 
surface vessels and air assets to simulate opposing forces, using mid-
frequency active sonar when training with submarines, is critical to 
submarine crew training for deployed and combat operations. Surface 
ships and aircraft mimicking opposition forces present submarines with 
a realistic and complicated acoustic and tactical environment. The Navy 
expects real-world adversaries to target our submarines with active 
sonar. Without active sonar from opposition forces submarines do not 
get a realistic picture regarding if they successfully evaded 
detection. Surface warfare training is designed to support unit-level 
training requirements and group cross-platform events in 28 mission 
areas for surface ship certification prior to deployment.
    Additionally, the Navy will implement the Humpback Whale Special 
Reporting Area (December 15 through April 15) is comprised of 
additional areas of high humpback whale densities that overlap the 
Humpback Whale National Marine Sanctuary. This reporting is included in 
the exercise and monitoring reports that are an ongoing Navy 
requirement and are submitted to NMFS annually. Special reporting data, 
along with all other reporting requirements, are considered during 
adaptive management to determine if additional mitigation may be 
required. The Navy currently reports to NMFS the total hours (from 
December 15 through April 15) of all hull-mounted mid-frequency active 
sonar usage occurring in the Humpback Whale Special Reporting Area, 
plus a 5 km buffer, but not including the Pacific Missile Range 
Facility. The Navy will continue this reporting for the Humpback Whale 
Special Reporting Area.
    In regard to limits on sonar and explosives should be adopted in 
the ESA-designated critical habitat for the Hawaiian monk seal and 
false killer whale, the Navy will cap MFAS for the entire false killer 
whale BIA adjacent to the island of Hawaii and a portion of the false 
killer whale BIA north of Maui and Molokai as follows. The Navy already 
will to limit explosive use in the entire false killer whale BIA 
adjacent to the island of Hawaii. The Navy will now add year-round 
limitation on explosives to the 4-Islands Region Mitigation Area, which 
includes a portion of the false killer whale BIA north of Maui and 
Molokai. For the Hawaii Island Mitigation Area (year-round): The Navy 
will not conduct more than 300 hours of surface ship hull-mounted MFAS 
sonar MF1 (MF1) or 20 hours of MFAS dipping sonar MF4 (MF4), or use 
explosives during training and testing year-round. For the 4-Islands 
Region Mitigation Area (November 15-April 15 for active sonar, year-
round for explosives): The Navy will not use surface ship hull-mounted 
MFAS sonar MF1 from November 15-April 15 and explosive year-round 
during training or

[[Page 66906]]

testing activities. The remaining false killer whale BIA overlaps with 
areas (e.g., Kaiwi Channel) where additional mitigations were found to 
be impractical.
    In regard to limits on sonar and explosives in ESA-designated 
critical habitat for Hawaiian monk seal, the Navy's training and 
testing activities do occur in a portion of the ESA-designated critical 
habitat for Hawaiian monk seals, which is of specific importance to the 
species. However, monk seals in the main Hawaiian Islands have 
increased while the Navy has continued its activities, even though the 
Hawaiian monk seal overall population trend has been on a decline from 
2004 through 2013, with the total number of Hawaiian monk seals 
decreasing by 3.4 percent per year (Carretta et al., 2017). While the 
decline has been driven by the population segment in the northwestern 
Hawaiian Islands, the number of documented sightings and annual births 
in the main Hawaiian Islands has increased since the mid-1990s (Baker, 
2004; Baker et al., 2016). In the main Hawaiian Islands, the estimated 
population growth rate is 6.5 percent per year (Baker et al., 2011; 
Carretta et al., 2017). Of note, in the 2013 HRC Monitoring Report, 
tagged monk seals did not show any behavioral changes during periods of 
MFAS.
    The Hawaii Island Mitigation Area overlaps all of their critical 
habitat around the Island of Hawaii (as well as the southern end of 
Maui) and, by not using explosives or the most impactful sonar sources 
in this, thereby reduces the likelihood that take might impact 
reproduction or survival by interfering with important feeding or 
resting behaviors (potentially having adverse impacts on energy 
budgets) or separating mothers and pups in times when pups are more 
susceptible to predation and less able to feed or otherwise take care 
of themselves. The 4-Islands Mitigation Area overlaps with ESA-
designated critical habitat around Maui, Lanai, and Molokai.
    Comment 67: A commenter commented that in the proposed rule, NMFS 
estimates 588 takes annually will cause multiple instances of exposure 
to insular false killer whales, taking 400 percent of the population. 
As the potential biological removal is 0.18 animals, the loss of a 
single individual, or an impairment to its health and fitness, could 
place the species on an extinction trajectory. NMFS must consider 
additional mitigation in the designated critical habitat, as well as 
excluded areas, to ensure a negligible impact on false killer whales.
    Response: The commenter is conflating behavioral take with 
mortality take addressed in PBR. There are no insular false killer 
whale mortality takes modeled, anticipated, or authorized. 400 percent 
of the population would mean that all animals would be behaviorally 
harassed an average of 4 times per year, or once per season. The short 
term biological reaction of an animal for periods of minutes to hours a 
few times a year would not have any fitness impacts to the individual 
let alone any population level impacts. NMFS confirms that these 
impacts are negligible. Additionally, much of the Navy's mitigations on 
Hawaii and the 4 island region encompass areas that overlap with high 
use insular false killer whale habitat and thus already mitigate 
impacts. From the Navy consultation with NMFS under the ESA for insular 
false killer whale critical habitat, less than 12 percent of modeled 
takes would take place in or near insular false killer whale critical 
habitat. These takes as explained previously would be transitory 
(short-duration), and spread out in time and space.''
    Comment 68: A commenter recommended establishing stand-off 
distances around the Navy's mitigation areas to the greatest extent 
practicable, allowing for variability in size given the location of the 
area, the type of operation at issue, and the species of concern.
    Response: Mitigation areas are typically developed in consideration 
of both the area that is being protected and the distance from the 
stressor in question that is appropriate to maintain to ensure the 
protection. Sometimes this results in the identification of the area 
plus a buffer, and sometimes both the protected area and the buffer are 
considered together in the designation of the edge of the area. We note 
that the edges of a protected area are typically of less importance to 
a protected stock or behavior, since important areas often have a 
density gradient that lessens towards the edge. Also, while a buffer of 
a certain size may be ideal to alleviate all impacts of concern, a 
lessened buffer does not mean that the protective value is 
significantly reduced, as the core of the area is still protected. 
Also, one should not assume that activities are constantly occurring in 
the area immediately adjacent to the protected area.
    These issues were considered here, and the Navy has indicated that 
the mitigation identified in Chapter 5 (Mitigation), Section 5.4 
(Mitigation Areas to be Implemented) of the HSTT FEIS/OEIS represents 
the maximum mitigation within mitigation areas and the maximum size of 
mitigation areas that are practicable to implement under the Proposed 
Action. The Navy has communicated (and NMFS concurs with the 
assessment) that implementing additional mitigation (e.g., stand-off 
distances that would extend the size of the mitigation areas) beyond 
what is described in Chapter 5 (Mitigation), Section 5.4 (Mitigation 
Areas to be Implemented) of the HSTT FEIS/OEIS would be impracticable 
due to implications for safety (the ability to avoid potential 
hazards), sustainability (based on the amount and type of resources 
available, such as funding, personnel, and equipment)), and the Navy's 
ability to continue meeting its Title 10 requirements.
Additional Mitigation Research
    Comment 69: A commenter recommended NMFS consider additional 
mitigation measures to prescribe or research including: (1) Research 
into sonar signal modifications; (2) mitigation and research on Navy 
ship speeds (the commenter recommended that the agency require the Navy 
to collect and report data on ship speed as part of the EIS process); 
and (3) compensatory mitigation for the adverse impacts of the 
permitted activity on marine mammals and their habitat that cannot be 
prevented or mitigated.
    Response: NMFS consulted with the Navy regarding potential research 
into additional mitigation measures and discussion is included below.
    1. Research into sonar signal modification--Sonar signals are 
designed explicitly to provide optimum performance at detecting 
underwater objects (e.g., submarines) in a variety of acoustic 
environments. The Navy acknowledges that there is very limited data, 
and some suggest that up or down sweeps of the sonar signal may result 
in different animal reactions; however, this is a very small data 
sample, and this science requires further development. If future 
studies indicate this could be an effective approach, then NMFS and the 
Navy will investigate the feasibility and practicability to modify 
signals, based on tactical considerations and cost, to determine how it 
will affect the sonar's performance.
    2. Mitigation and research on Navy ship speeds inclusive of Navy 
collecting and reporting data on ship speed as part of the EIS--The 
Navy conducted an operational analysis of potential mitigation areas 
throughout the entire Study Area to consider a wide range of mitigation 
options, including but not limited to vessel speed restrictions. As

[[Page 66907]]

discussed in Chapter 3, Section 3.0.3.3.4.1 (Vessels and In-Water 
Devices) of the HSTT FEIS/OEIS, Navy ships transit at speeds that are 
optimal for fuel conservation or to meet operational requirements. 
Operational input indicated that implementing additional vessel speed 
restrictions beyond what is identified in Chapter 5 (Mitigation), 
Section 5.4 (Mitigation Areas to be Implemented) of the HSTT FEIS/OEIS 
would be impracticable to implement due to implications for safety and 
sustainability. In its assessment of potential mitigation, the Navy 
considered implementing additional vessel speed restrictions (e.g., 
expanding the 10 kn restriction to other activities). The Navy 
determined that implementing additional vessel speed restrictions 
beyond what is described in Chapter 5 (Mitigation), Section 5.5.2.2 
(Restricting Vessel Speed) of the HSTT FEIS/OEIS would be impracticable 
due to implications for safety (the ability to avoid potential 
hazards), sustainability (maintain readiness), and the Navy's ability 
to continue meeting its Title 10 requirements to successfully 
accomplish military readiness objectives. Additionally, as described in 
Chapter 5 (Mitigation), Section 5.5.2.2 (Restricting Vessel Speed) of 
the HSTT FEIS/OEIS, any additional vessel speed restrictions would 
prevent vessel operators from gaining skill proficiency, would prevent 
the Navy from properly testing vessel capabilities, or would increase 
the time on station during training or testing activities as required 
to achieve skill proficiency or properly test vessel capabilities, 
which would significantly increase fuel consumption. As discussed in 
Chapter 5 (Mitigation), Section 5.3.4.1 (Vessel Movement) of the HSTT 
FEIS/OEIS, the Navy implements mitigation to avoid vessel strikes 
throughout the Study Area. As directed by the Chief of Naval Operations 
Instruction (OPNAVINST) 5090.1D, Environmental Readiness Program, Navy 
vessels report all marine mammal incidents worldwide, including ship 
speed. Therefore, the data required for ship strike analysis discussed 
in the comment is already being collected. Any additional data 
collection required would create an unnecessary and impracticable 
administrative burden on the Navy.
    3. Compensatory mitigation--For years, the Navy has implemented a 
very broad and comprehensive range of measures to mitigate potential 
impacts to marine mammals from military readiness activities. As the 
HSTT FEIS/OEIS documents in Chapter 5 (Mitigation), the Navy is 
proposing to expand these measures further where practicable. Aside 
from direct mitigation, as noted by the commenter, the Navy engages in 
an extensive spectrum of other activities that greatly benefit marine 
species in a more general manner that is not necessarily tied to just 
military readiness activities. As noted in Chapter 3, Section 3.0.1.1 
(Marine Species Monitoring and Research Programs) of the HSTT FEIS/
OEIS, the Navy provides extensive investment for research programs in 
basic and applied research. The U.S. Navy is one of the largest sources 
of funding for marine mammal research in the world, which has greatly 
enhanced the scientific community's understanding of marine species 
much more generally. The Navy's support and marine mammal research 
includes: Marine mammal detection, including the development and 
testing of new autonomous hardware platforms and signal processing 
algorithms for detection, classification, and localization of marine 
mammals; improvements in density information and development of 
abundance models of marine mammals; and advancements in the 
understanding and characterization of the behavioral, physiological 
(hearing and stress response), and potentially population-level 
consequences of sound exposure on marine life. Compensatory mitigation 
is not required to be imposed upon Federal agencies under the MMPA. 
Importantly, the commenter did not recommend any specific measure(s), 
rendering it impossible to conduct any meaningful evaluation of its 
recommendation. Finally, many of the methods of compensatory mitigation 
that have proven successful in terrestrial settings (purchasing or 
preserving land with important habitat, improving habitat through 
plantings, etc.) are not applicable in a marine setting with such far-
ranging species. Thus, any presumed conservation value from such an 
idea would be purely speculative at this time.
    Comment 70: A commenter recommended that given the paucity of 
information on marine mammal habitat currently available for the HSTT 
Study Area, that efforts be undertaken in an iterative manner by NMFS, 
and the Navy, to identify additional important habitat areas across the 
HSTT Study Area, using the full range of data and information available 
to the agencies (e.g., habitat-based density models, NOAA-recognized 
BIAs, survey data, oceanographic and other environmental data, etc.).
    Response: NMFS and the Navy used the best available scientific 
information (e.g., SARs and numerous study reports from Navy-funded 
monitoring and research in the specific geographic region) in assessing 
density, distribution, and other information regarding marine mammal 
use of habitats in the HSTT Study Area. In addition, NMFS consulted 
LaBrecque et al. (2015), which provides a specific, detailed assessment 
of known BIAs, which may be region-, species-, and/or time-specific, 
include reproductive areas, feeding areas, migratory corridors, and 
areas in which small and resident populations are concentrated. While 
the science of marine mammal occurrence, distribution, and density 
resides as a core NMFS mission, the Navy does provide extensive support 
to the NMFS mission via ongoing HSTT specific monitoring as detailed in 
this final rule. Also included are direct Navy funding support to NMFS 
for programmatic marine mammal surveys in Hawaii and the U.S. West 
Coast, and spatial habitat model improvements.''
    Comment 71: A commenter recommended integration of important 
habitat areas to improve resolution of operations. The delineation of 
BIAs by NOAA, the updates made by the Navy to its predictive habitat 
models, and evidence of additional important habitat areas within the 
HSTT Study Area, provide the opportunity for the agencies to improve 
upon their current approach to the development of alternatives by 
improving resolution of their analysis of operations. A commenter 
offered the following thoughts for consideration.
    They state that recognizing that important habitat areas imply the 
non-random distribution and density of marine mammals in space and 
time, both the spatial location and the timing of training and testing 
events in relation to those areas is a significant determining factor 
in the assessment of acoustic impacts. Levels of acoustic impact 
derived from the NAEM are likely to be under- or over-estimated 
depending on whether the location of the modeled event is further from 
the important habitat area, or closer to it, than the actual event. 
Thus, there is a need for the Navy to compile more information 
regarding the number, nature, and timing of testing and training events 
that take place within, or in close proximity to, important habitat 
areas, and to refine its scale of analysis of operations to match the 
scale of the habitat areas that are considered to be important. While 
the proposed rule, in assessing environmental impacts on marine 
mammals, breaks down estimated impacts by general region (i.e., HRC and 
SOCAL), the resolution is seldom greater than range complex or

[[Page 66908]]

homeport and is not specifically focused on areas of higher biological 
importance. Current and ongoing efforts to identify important habitat 
areas for marine mammals should be used by NMFS and by the Navy as a 
guide to the most appropriate scale(s) for the analysis of operations.
    Response: In their take request and effects analysis provided to 
NMFS, the Navy considered historic use (number and nature of training 
and testing activities) and locational information of training and 
testing activities when developing modelling boxes. The timing of 
training cycles and testing needs varies based on deployment 
requirements to meet current and emerging threats. Due to the 
variability, the Navy's description of its specified activities is 
structured to provide flexibility in training and testing locations, 
timing, and number. In addition, information regarding the exact 
location of sonar usage is classified. Due to the variety of factors, 
many of which influence locations that cannot be predicted in advance 
(e.g., weather), the analysis is completed at a scale that is necessary 
to allow for flexibility. The purpose of the Navy's quantitative 
acoustic analysis is to provide the best estimate of impact/take to 
marine mammals and ESA listed species for the regulatory and ESA 
section 7 consultation analyses. Specifically, the analysis must take 
into account multiple Navy training and testing activities over large 
areas of the ocean for multiple years; therefore, analyzing activities 
in multiple locations over multiple seasons produces the best estimate 
of impacts/take to inform the HSTT FEIS/OEIS and regulators. Also, the 
scale at which spatially explicit marine mammal density models are 
structured is determined by the data collection method and the 
environmental variables that are used to build the model. Therefore, 
altogether, given the variables that determine when and where the Navy 
trains and tests, as well as the resolution of the density data, the 
analysis of potential impacts is scaled to the level that the data 
fidelity will support. NMFS has worked with the Navy over the years to 
increase the spatio-temporal specificity of the descriptions of 
activities planned in or near areas of biological importance, when 
possible (e.g., in BIAs or Sanctuaries, where possible), and NMFS is 
confident that the granularity of information provided sufficiently 
allows for an accurate assessment of both the impacts of the Navy's 
activities on marine mammal populations and the protective measures 
evaluated to mitigate those impacts.
Monitoring Recommendations
    Comment 72: A commenter recommended that NMFS require that the Navy 
continue to conduct long-term monitoring with the aim to provide 
baseline information on occurrence, distribution, and population 
structure of marine mammal species and stocks, and baseline information 
upon which the extent of exposure to disturbance from training and 
testing activities at the individual, and ultimately, population level-
impacts, and the effectiveness of mitigation measures, can be 
evaluated. The commenter recommended individual-level behavioral-
response studies, such as focal follows and tagging using DTAGs, 
carried out before, during, and after Navy training and testing 
activities. The commenter recommended prioritizing DTAG studies that 
further characterize the suite of vocalizations related to social 
interactions. The commenter recommends the use of unmanned aerial 
vehicles. The commenter recommended that NMFS require the Navy to use 
these technologies for assessing marine mammal behavior before, during, 
and after Navy training and testings (e.g., swim speed and direction, 
group cohesion). Additionally, the commenter recommended studies into 
how these technologies can be used to assess body condition be 
supported as this can provide an important indication of energy budget 
and health, which can inform the assessment of population-level 
impacts.
    Response: Broadly speaking, NMFS works closely with the Navy in the 
identification of monitoring priorities and the selection of projects 
to conduct, continue, modify, and/or stop through the Adaptive 
Management process, which includes annual review and debriefs by all 
scientists conducting studies pursuant to the Navy's MMPA rule. The 
process NMFS and the Navy have developed allows for comprehensive and 
timely input from the Navy and other stakeholders that is based on 
rigorous reporting out from the Navy and the researchers doing the 
work. Further, the Navy is pursuing many of the topics that the 
commenter identifies, either through the Navy monitoring required under 
the MMPA and ESA, or through Navy-funded research programs (ONR and 
LMR). We are confident that the monitoring conducted by the Navy 
satisfies the requirements of the MMPA.
    The Navy established the Strategic Planning Process under the 
marine species monitoring program to help structure the evaluation and 
prioritization of projects for funding. Chapter 5 (Mitigation), Section 
5.1.2.2.1.3 (Strategic Planning Process) of the HSTT FEIS/OEIS provides 
a brief overview of the Strategic Planning Process. More detail, 
including the current intermediate scientific objectives, is available 
on the monitoring portal as well as in the Strategic Planning Process 
report. The Navy's evaluation and prioritization process is driven 
largely by a standard set of criteria that help the steering committee 
evaluate how well a potential project would address the primary 
objectives of the monitoring program. NMFS has opportunities to provide 
input regarding the Navy's intermediate scientific objectives as well 
as providing feedback on individual projects through the annual program 
review meeting and annual report. For additional information, please 
visit: https://www.navymarinespeciesmonitoring.us/about/strategic-planning-process/.
    Details on the Navy's involvement with future research will 
continue to be developed and refined by the Navy and NMFS through the 
consultation and adaptive management processes, which regularly 
consider and evaluate the development and use of new science and 
technologies for Navy applications. The Navy has indicated that it will 
continue to be a leader in funding of research to better understand the 
potential impacts of Navy training and testing activities and to 
operate with the least possible impacts while meeting training and 
testing requirements.
    (1) Individual-level behavioral-response studies--In addition to 
the Navy's marine species monitoring program investments for 
individual-level behavioral-response studies, the Office of Naval 
Research Marine Mammals and Biology program and the Navy's Living 
Marine Resources program continue to heavily invest in this topic. For 
example, the following studies are currently being funded:

<bullet> The Southern California Behavioral Response Study 
(Principal Investigators: John Calambokidis and Brandon Southall)
<bullet> Cuvier's Beaked Whale and Fin Whale Behavior During 
Military Sonar Operations: Using Medium-term Tag Technology to 
Develop Empirical Risk Functions (Principal Investigators: Greg 
Schorr and Erin Falcone)
<bullet> 3S3-Behavioral responses of sperm whales to naval sonar 
(Principal Investigators: Petter Kvadsheim and Frans-Peter Lam)
<bullet> Measuring the effect of range on the behavioral response of 
marine mammals through the use of Navy sonar (Principal 
Investigators: Stephanie Watwood and Greg Schorr)

[[Page 66909]]

<bullet> Behavioral response evaluations employing robust baselines 
and actual Navy training (BREVE) (Principal Investigators: Steve 
Martin, Tyler Helble, Len Thomas)
<bullet> Integrating remote sensing methods to measure baseline 
behavior and responses of social delphinids to Navy sonar (Principal 
Investigators: Brandon Southall, John Calambokidis, John Durban).

    (2) DTAGS to characterize social communication between individuals 
of a species or stock, including mothers and calves. Furthermore, DTAGs 
are just one example of animal movement and acoustics tag. From the 
Navy's Office of Naval Research and Living Marine Resource programs, 
Navy funding is being used to improve a suite of marine mammal tags to 
increase attachment times, improve data being collected, and improve 
data satellite transmission--The Navy has funded a variety of projects 
that are collecting data that can be used to study social interactions 
amongst individuals. Examples of these projects include:

<bullet> Southern California Behavioral Response Study (Principal 
Investigators: John Calambokidis and Brandon Southall)
<bullet> Tagging and Tracking of Endangered North Atlantic Right 
Whales in Florida Waters (Principal Investigators: Doug Nowacek and 
Susan Parks). This project involves the use of DTAGs, and data 
regarding the tagged individual and group are collected in 
association with the tagging event. In addition to the vocalization 
data that is being collected on the DTAGs, data is collected on 
individual and group behaviors that are observed, including between 
mother/calf pairs when applicable. The Navy will continue to collect 
this type of data when possible.
<bullet> Integrating remote sensing methods to measure baseline 
behavior and responses of social delphinids to Navy sonar (Principal 
Investigators: Brandon Southall, John Calambokidis, John Durban)
<bullet> Acoustic Behavior of North Atlantic Right Whale (Eubalaena 
glacialis) Mother-Calf Pairs (Principal Investigators: Susan E. 
Parks and Sofie Van Parijs). The long-term goal of this project is 
to quantify the behavior of mother-calf pairs from the North 
Atlantic right whale to determine: a) why mothers and calves are 
more susceptible to collisions with vessels and b) the vocal 
behavior of this critical life stage to assess the effectiveness of 
passive acoustic monitoring to detect mother-calf pairs in important 
habitat areas (see https://www.onr.navy.mil/reports/FY15/mbparks.pdf).
<bullet> Social Ecology and Group Cohesion in Pilot Whales and Their 
Responses to Playback of Anthropogenic and Natural Sounds (Principal 
Investigator: Frants H. Jensen). This project investigates the 
social ecology and cohesion of long-finned pilot whales as part of a 
broad multi-investigator research program that seeks to understand 
how cetaceans are affected by mid-frequency sonar and other sources 
of anthropogenic noise (see https://www.onr.navy.mil/reports/FY15/mbjensen.pdf).

    (3) Unmanned Aerial Vehicles to assess marine mammal behavior 
before, during, and after Navy training and testing activities (e.g., 
swim speed and direction, group cohesion)--Studies that use unmanned 
aerial vehicles to assess marine mammal behaviors and body condition 
are being funded by the Office of Naval Research Marine Mammals and 
Biology program. Although the technology shows promise, the field 
limitations associated with the use of this technology has hindered the 
useful application in behavioral response studies in association with 
Navy training and testing events. For safety, research vessels cannot 
remain in close proximity to Navy vessels during Navy training or 
testing events, so battery life of the unmanned aerial vehicles has 
been an issue. However, as the technology improves, the Navy will 
continue to assess the applicability of this technology for the Navy's 
research and monitoring programs. An example project is Integrating 
Remote Sensing Methods to Measure Baseline Behavior and Responses of 
Social Delphinids to Navy sonar (Principal Investigators: Brandon 
Southall, John Calambokidis, and John Durban).
    (4) NMFS asked the Navy to expand funding to explore the utility of 
other, simpler modeling methods that could provide at least an 
indicator of population-level effects, even if each of the behavioral 
and physiological mechanisms are not fully characterized--The Office of 
Naval Research Marine Mammals and Biology program has invested in the 
Population Consequences of Disturbance (PCoD) model, which provides a 
theoretical framework and the types of data that would be needed to 
assess population level impacts. Although the process is complicated 
and many species are data poor, this work has provided a foundation for 
the type of data that is needed. Therefore, in the future, relevant 
data that is needed for improving the analytical approaches for 
population level consequences resulting from disturbances will be 
collected during projects funded by the Navy's marine species 
monitoring program. General population level trend analysis is 
conducted by NMFS through its stock assessment reports and regulatory 
determinations. The Navy's analysis of effects to populations (species 
and stocks) of all potentially exposed marine species, including marine 
mammals and sea turtles, is based on the best available science as 
discussed in Sections 3.7 (Marine Mammals) and 3.8 (Reptiles) of the 
HSTT FEIS/OEIS. PCoD models, similar to many fisheries stock assessment 
models, once developed will be powerful analytical tools when mature. 
However, currently they are dependent on too many unknown factors for 
these types of models to produce a reliable answer. As discussed in the 
Monitoring section of the final rule, the Navy's marine species 
monitoring program typically supports 10-15 projects in the Atlantic at 
any given time. Current projects cover a range of species and topics 
from collecting baseline data on occurrence and distribution, to 
tracking whales and sea turtles, to conducting behavioral response 
studies on beaked whales and pilot whales. The Navy's marine species 
monitoring web portal provides details on past and current monitoring 
projects, including technical reports, publications, presentations, and 
access to available data and can be found at: https://www.navymarinespeciesmonitoring.us/regions/atlantic/current-projects/. 
A list of the monitoring studies that the Navy is currently planning 
under this rule are listed at the bottom of the Monitoring section of 
this final rule.

Negligible Impact Determination

General
    Comment 73: Commenters commented that NMFS' analytical approach for 
negligible impact determination is not transparent and that the methods 
and resulting data cannot be substantiated with the information 
provided. The Commission stated that in general, NMFS has based 
negligible impact determinations associated with incidental take 
authorizations on abundance estimates provided either in its Stock 
Assessment Reports (SARs) or other more recent published literature. 
For the HSTT proposed rule, NMFS used abundance estimates as determined 
by the Navy's underlying density estimates rather than abundance 
estimates from either the SARs or published literature. NMFS did also 
not specify how it determined the actual abundance given that many of 
the densities differ on orders of kilometers. Interpolation or 
smoothing, and potentially extrapolation, of data likely would be 
necessary to achieve NMFS' intended goal--it is unclear whether any 
such methods were implemented. In addition, it is unclear whether NMFS 
estimated the abundances in the same manner beyond the U.S. EEZ as it 
did within the U.S. EEZ for HRC and why it did not compare takes within 
the U.S. EEZ and beyond the U.S. EEZ for

[[Page 66910]]

SOCAL, given that a larger proportion of the Navy's SOCAL action area 
is beyond the U.S. EEZ than HRC. Furthermore, NMFS did not specify how 
it determined the proportion of total takes that would occur beyond the 
U.S. EEZ. Moreover, the `instances' of the specific types of taking 
(i.e., mortality, Level A and B harassment) do not match the total 
takes `inside and outside the EEZ' in Tables 69-81 (where applicable) 
or those take estimates in Tables 41-42 and 67-68. It also appears the 
`instances' of take columns were based on only those takes in the U.S. 
EEZ for HRC rather than the area within and beyond the U.S. EEZ. It 
further is unclear why takes were not apportioned within and beyond the 
U.S. EEZ for SOCAL. Given that the negligible impact determination is 
based on the total taking in the entire study area, NMFS should have 
partitioned the takes in the `instances' of take columns in Tables 69-
81 for all activities that occur within and beyond the U.S. EEZ. One 
commenter further asserts that any ``small numbers'' determination that 
relies on abundance estimates derived simplistically from modeled 
densities is both arbitrary and capricious. The commenters assert that 
NMFS should, at least for data rich species, derive its absolute 
abundance estimates from NMFS' SARs or more recently published 
literature.
    Response: NMFS' Analysis and Negligible Impact Determination 
section has been updated and expanded in the final rule to clarify the 
issues the Commenters raise here (as well as others). Specifically, 
though, NMFS uses both the Navy-calculated abundance (based on the 
Navy-calculated densities described in detail in the Estimated Take of 
Marine Mammal section) and the SARs abundances, where appropriate, in 
the negligible impact analysis--noting that the nature of the overlap 
of the Navy Study Area with the U.S. EEZ is different in Hawaii versus 
SOCAL, supporting different analytical comparisons.
    NMFS acknowledges that there were a few small errors in the take 
numbers in the proposed rule; however, they have been corrected (i.e., 
the take totals in Tables 41 and 42 for a given stock now equal the 
``in and outside the U.S. EEZ'' take totals in Tables X-Y) and the 
minor changes do not affect the analysis or determinations in the rule.
    Also, the Commenters are incorrect that the instances of take for 
HRC do not reflect the take both within and outside the U.S. EEZ. They 
do. Last, one commenter mentions the agency making a ``small numbers'' 
determination, but such a determination is not applicable in the 
context of military readiness activities.
    Comment 74: A commenter commented that the activities proposed by 
the Navy include high-intensity noise pollution, vessel traffic, 
explosions, pile driving, and more at a massive scale. According to the 
commenter, NMFS has underestimated the amount of take and the adverse 
impact that it will have on marine mammals and their habitat.
    Response: NMFS has provided extensive information demonstrating 
that the best available science has been used to estimate the amount of 
take, and further to analyze the impacts that all of these takes 
combined will have on the affected species and stocks. As described in 
the Analysis and Negligible Impact Determination section, this 
information and our associated analyses support the negligible impact 
determinations necessary to issue these regulations.
    Comment 75: A commenter commented that blue whales exposed to mid-
frequency sonar (with received levels of 110 to 120 dB re 1 [mu]Pa) are 
less likely to produce calls associated with feeding behavior. They 
cite the Goldbogen et al. (2013) study (and a subsequent study) as 
extremely concerning because of the potential impacts of sonar on the 
essential life functions of blue whales as it found that sonar can 
disrupt feeding and displace blue whales from high-quality prey 
patches, significantly impacting their foraging ecology, individual 
fitness, and population health. They also state that mid-frequency 
sonar has been associated with several cases of blue whale stranding 
events and that low-frequency anthropogenic noise can mask calling 
behavior, reduce communication range, and damage hearing. These impacts 
from sonar on blue whales suggest that the activities' impacts would 
have long-term, non-negligible impacts on the blue whale population.
    Response: As described in this final rule in the Analysis and 
Negligible Impact Determination section, NMFS has fully considered the 
effects that exposure to sonar can have on blue whales, including 
impacts on calls and feeding and those outlined in the Goldbogen study. 
However, as discussed, any individual blue whale is not expected to be 
exposed to sonar and taken on more than several days per year. Thus, 
while vocalizations may be impacted or feeding behaviors temporarily 
disrupted, this small scale of impacts is not expected to affect 
reproductive success or survival of any individuals, especially given 
the limitations on sonar and explosive use within blue whale BIAs. Of 
additional note, while the blue whale behavioral response study (BRS) 
in Southern California documented some foraging responses by blue 
whales to simulated Navy sonar, any response was highly variable by 
individual and context of the exposure. There were, for instance, some 
individual blue whales that did not respond. Recent Navy-funded blue 
whale tracking has documented wide ranging movements through Navy areas 
such that any one area is not used extensively for foraging. More long-
term blue whale residency occurs north of and outside of the HSTT Study 
Area. Further, we disagree with the assertion that MFAS has been 
causally associated with blue whale strandings. This topic was 
discussed at length in the proposed rule and there is no data causally 
linking MFAS use with blue whale strandings.
    Comment 76: A commenter commented that NMFS cannot consider the 
additional mortality/serious injury, including the 0.2 in the proposed 
authorization for ship strike for blue whales, to have a negligible 
impact determination for this stock. They also state that counts of 
mortality/serious injury do not account for the additional takes 
proposed to be authorized that cumulatively can have population level 
impacts from auditory injury and behavioral disturbance. Similarly, the 
commenter commented that NMFS cannot consider the proposed 
authorization for 0.4 annual mortality/serious injury to have a 
negligible impact on the CA/OR/WA stock of humpback whales because take 
is already exceeding the potential biological removal, and especially 
concerning is any take authorized for the critically endangered Central 
America population that would have significant adverse population 
impacts.
    Response: As described in detail in the Estimated Take of Marine 
Mammals section, the Navy and NMFS have revisited and re-analyzed the 
Navy's initial request for takes by mortality of blue and humpback 
whales from vessel strike and determined that only 1 strike of either 
would be anticipated over the course of 5 years, and therefore 
authorized the lesser amount. Further, NMFS has expanded and refined 
the discussion of mortality take, PBR, and our negligible impact 
finding in the Serious Injury and Mortality sub-section of the Analysis 
and Negligible Impact Determination section and do not repeat it here.
    Comment 77: A commenter commented that the estimated

[[Page 66911]]

population size for the Hawaii stock of sei whales is only 178 animals, 
and the potential biological removal is 0.2 whales per year. According 
to the Commenters, NMFS admits that the mortality for the Hawaii stock 
of sei whales is above potential biological removal. The commenter 
asserted that the conclusion that the action will have a negligible 
impact on this stock is arbitrary and capricious.
    Response: As described in detail in the Estimated Take of Marine 
Mammals section, the Navy and NMFS revisited and re-analyzed the Navy's 
initial request for the take of a sei whale from vessel strike and 
determined that this take is unlikely to occur and, therefore, it is 
not authorized.
    Comment 78: A commenter commented that any take of Hawaiian monk 
seal by the proposed activities will have a non-negligible impact given 
the precarious status of this species.
    Response: NMFS' rationale for finding that the Navy's activity will 
have a negligible impact on monk seals is included in the Pinniped 
subsection of the Analysis and Negligible Impact Determination section 
and is not re-printed here. Nonetheless we reiterate that no mortality 
or injury due to tissue damage is anticipated or authorized, only one 
instance of PTS is estimated and authorized, and no individual monk 
seal is expected to be exposed to stressors that would result in take 
more than a few days a year. Further, the Hawaii Island and 4-Island 
mitigation areas provide significant protection of monk seal critical 
habitat in the Main Hawaiian Islands, reducing impacts form sonar and 
explosives around a large portion of pupping beaches and foraging 
habitat, as described in the Mitigation Measures section.
Cumulative and Aggregate Effects
    Comment 79: One commenter asserted that NMFS has not apparently 
considered the impact of Navy activities on a population basis for many 
of the marine mammal populations within the HSTT Study Area. Instead, 
it has lodged discussion for many populations within broader 
categories, most prominently ``mysticetes'' (14 populations) and 
``odontocetes'' (37 populations), that in some cases correspond to 
general taxonomic groups. Such grouping of stocks elides important 
differences in abundance, demography, distribution, and other 
population-specific factors, making it difficult to assume ``that the 
effects of an activity on the different stock populations'' are 
identical. That is particularly true where small, resident populations 
are concerned, and differences in population abundance, habitat use, 
and distribution relative to Navy activities can be profoundly 
significant. Additionally, the commenter states that NMFS assumed that 
all of the Navy's estimated impacts would not affect individuals or 
populations through repeated activity--even though the takes 
anticipated each year would affect the same populations and, indeed, 
would admittedly involve extensive use of some of the same 
biogeographic areas.
    Response: NMFS provides information regarding broader groups in 
order to avoid repeating information that is applicable across multiple 
species or stocks, but analyses have been conducted and determinations 
made specific to each stock. The method used to avoid repeating 
information applicable to a number of species or stocks while also 
presenting and integrating all information applicable to particular 
species or stocks is described in the rule. Also, NMFS' analysis does 
address the fact that some individuals may be repeatedly impacted and 
how those impacts may or may not accrue to more serious effects. The 
Analysis and Negligible Impacts Determination section has been expanded 
and refined to better explain this.
    Comment 80: NMFS' negligible impact analysis for Cuvier's beaked 
whales is predicated on a single take estimate for the CA/OR/WA stock. 
This is deeply problematic as the species is known to occur in small, 
resident populations within the SOCAL Range Complex. These populations 
are acutely vulnerable to Navy sonar. Cuvier's beaked whales have 
repeatedly been associated with sonar-related pathology, are known to 
react strongly to sonar at distances up to 100 kilometers, and are 
universally regarded to be among the most sensitive of all marine 
mammals to anthropogenic noise (Falcone et al., 2017). Some 
populations, such as the one in San Nicholas Basin that coincides with 
the Navy's much-used Southern California ASW Range (SOAR), are 
repeatedly exposed to sonar, posing the same risk of population-wide 
harm documented on a Navy range in the Bahamas (Falcone and Schorr, 
2013). The broad take estimates presented in the Proposed Rule, and the 
negligible impact analysis that they are meant to support, provide no 
insight into the specific impacts proposed for these small populations.
    Response: NMFS acknowledges the sensitivity of small resident 
populations both in our analyses and in the identification of 
mitigation measures, where appropriate. However, we are required to 
make our negligible impact determination in the context of the MMPA-
designated stock, which, in the case of the CA/OR/WA stock of Cuvier's 
beaked whale, spans the U.S. EEZ off the West Coast. As described in 
our responses to previous comments, NMFS and the Navy have fully 
accounted for the sensitivity of Cuvier's beaked whales in the 
behavioral thresholds and the estimation of take. Further, contrary to 
the assertions of the commenter, NMFS has absolutely considered the 
potential impacts of repeated takes on individuals that show site 
fidelity and that analysis can be found in the Analysis and Negligible 
Impact Determination section, which has been refined and updated since 
the proposed rule based on public input. Nonetheless, in 2018, an 
estimate of overall abundance of Cuvier's beaked whales at the Navy's 
instrumented range in San Nicolas Basin was obtained using new dive-
counting acoustic methods and an archive of passive acoustic M3R data 
representing 35,416 hours of data (DiMarzio, 2018; Moretti, 2017). Over 
the seven-year period from 2010-2017, there was no observed decrease 
and perhaps a slight increase in annual Cuvier's beaked whale abundance 
within San Nicolas Basin (DiMarzio, 2018). There does appear to be a 
repeated dip in population numbers and associated echolocation clicks 
during the fall centered around August and September (Moretti 2017, 
DiMarzio 2018). A similar August and September dip was noted by 
researchers using stand-alone off-range bottom passive acoustic devices 
in Southern California ([Scaron]irovi[cacute] et al., 2016; Rice et 
al., 2017). This dip in abundance may be tied to some as yet unknown 
population dynamic or oceanographic and prey availability dynamics.
    Comment 81: One commenter asserted that with respect to mortalities 
and serious injuries, NMFS' application of potential biological removal 
(PBR) is unclear and may not be consistent with its prior 
interpretations. The agency recognizes that PBR is a factor in 
determining whether the negligible impact threshold has been exceeded, 
but argues that, since PBR and negligible impact are different 
statutory standards, NMFS might find that an activity that kills marine 
mammals beyond what PBR could support would not necessarily exceed the 
negligible impact threshold. Regardless, however, of whether Congress 
intended PBR as a formal constraint on NMFS' ability to issue 
incidental take permits under section 101(a)(5), NMFS' own definition 
of ``negligible impact'' prevents it from authorizing mortalities or 
other takes that would threaten the sustainability of

[[Page 66912]]

marine mammal stocks. Mortalities and serious injuries exceeding 
potential biological removal levels would do just that.
    Additionally, in assessing the consequences of authorized mortality 
below PBR, NMFS applies an ``insignificance'' standard, such that any 
lethal take below 10 percent of residual PBR is presumed not to exceed 
the negligible impact threshold. This approach seems inconsistent, 
however, with the regulatory thresholds established for action under 
the commercial fisheries provision of the Act, where bycatch of 1 
percent of total PBR triggers mandatory take reduction procedures for 
strategic marine mammal stocks. See 16 U.S.C. 1387(f)(1); 83 FR 5349, 
5349 (Feb. 7, 2018). NMFS should clarify why it has chosen 10 percent 
rather than, for example, 1 percent as its ``insignificance'' 
threshold, at least for endangered species and other populations 
designated as strategic under the MMPA.
    Response: NMFS disagrees that the consideration of PBR is unclear 
and notes that the narrative describing the application of PBR has been 
updated in this final rule to further explain how the agency considers 
this metric in the context of the negligible impact determination under 
section 101(a)(5)(A) (see the Serious Injury and Mortality sub-section 
of the Analysis and Negligible Impact Determination section) and is not 
repeated here. That discussion includes how PBR is calculated and 
therefore how it is possible for anticipated M/SI to exceed PBR or 
residual PBR and yet not adversely affect a particular species or stock 
through effects on annual rates of recruitment and survival.
    Regarding the insignificance threshold, as explained in the rule, 
residual PBR is a metric that can be used to inform the assessment of 
M/SI impacts, and the insignificance threshold is an analytical tool to 
help prioritize analyst effort. But the insignificance threshold is not 
applied as a strict presumption as described by the commenter. Although 
it is true that as a general matter M/SI that is less than 10 percent 
of residual PBR should have no effect on rates of recruitment or 
survival, the agency will consider whether there are other factors that 
should be considered, such as whether an UME is affecting the species 
or stock.
    The 10 percent insignificance threshold is an analytical tool that 
indicates that the potential mortality or serious injury is an 
insignificant incremental increase in anthropogenic mortality and 
serious injury that alone (in the absence of any other take and any 
other unusual circumstances) would clearly not affect rates of 
recruitment or survival. As such, potential mortality and serious 
injury at the insignificance-threshold level or below is evaluated in 
light of other relevant factors (such as an ongoing UME) and then 
considered in conjunction with any anticipated Level A or Level B 
harassment take to determine if the total take would affect annual 
rates of recruitment or survival. Ten percent was selected because it 
corresponds to the insignificance threshold under the MMPA framework 
for authorizing incidental take of marine mammals resulting from 
commercial fisheries. There the insignificance threshold, which also is 
10 percent of PBR, is ``the upper limit of annual incidental mortality 
and serious injury of marine mammal stocks by commercial fisheries that 
can be considered insignificant levels approaching a zero mortality and 
serious injury rate'' (see 50 CFR 229.2). A threshold that represents 
an insignificant level of mortality or serious injury approaching a 
zero mortality and serious injury rate was thought to be an appropriate 
level to indicate when, absent other factors, the agency can be 
confident that expected mortality and serious injury will not affect 
annual rates of recruitment and survival, without the need for 
significant additional analysis.
    Regarding the claim that NMFS' interpretation of PBR may be 
inconsistent with prior interpretations, we disagree. Rather, NMFS' 
interpretation of PBR has been utilized appropriately within the 
context of the different MMPA programs and associated statutory 
standards it has informed. The application of PBR under section 
101(a)(5)(A) also has developed and been refined in response to 
litigation and as the amount of and nature of M/SI requested pursuant 
to this section has changed over time, thereby calling for the agency 
to take a closer look at how M/SI relative to PBR relates to effects on 
rates of recruitment and survival. Specifically, until recently, NMFS 
had used PBR relatively few times to support determinations outside of 
the context of MMPA commercial fisheries assessments and decisions. 
Indeed, in Georgia Aquarium, Inc. v. Pritzker, 135 F. Supp.3d 1280 
(N.D. Ga. 2015), in ruling on a lawsuit in which the plaintiffs sought 
to use PBR as the reason they should be allowed to import animals from 
the Sahklin-Amur stock of beluga whales for public display, the Court 
summarized a ``handful'' of cases where NMFS had used PBR to support 
certain agency findings. The Court agreed that the agency does not have 
a ``practice and policy'' of applying PBR in all circumstances. 
Importantly, the Court stated that ``NMFS has shown that where the 
Agency has considered PBR outside of the U.S. commercial fisheries 
context, it has treated PBR as only one `quantitative tool' and that it 
is not used as the sole basis for its impact analyses,'' just as NMFS 
has done here for its negligible impact analyses.
    The examples considered by the Georgia Aquarium Court involved 
scientific research permits or subsistence harvest decisions where 
reference to PBR was one consideration among several. Thus, in one of 
the examples referenced by the Court, PBR was included to evaluate 
different alternatives in a 2007 EIS developed in support of future 
grants and permits related to research on northern fur seals and 
Steller sea lions (available at https://repository.library.noaa.gov/view/noaa/17331). Similarly, in the 2015 draft EIS on the Makah Tribe's 
request to hunt gray whales, different levels of harvest were compared 
against PBR along with other considerations in the various alternatives 
(available at https://www.westcoast.fisheries.noaa.gov/publications/protected_species/marine_mammals/cetaceans/gray_whales/makah_deis_feb_2015.pdf). Consistent with what the Georgia Aquarium 
Court found, in both of those documents PBR was one consideration in 
developing alternatives for the agency's EIS and not determinative in 
any decision-making process.
    After 2013 in response to an incidental take authorization request 
from NMFS' Southwest Fisheries Science Center that contained PBR 
analysis and more particularly in response to a District Court's March 
2015 ruling that NMFS' failure to consider PBR when evaluating lethal 
take under section 101(a)(5)(A) violated the requirement to use the 
best available science (see Conservation Council for Hawaii v. National 
Marine Fisheries Service, 97 F. Supp.3d 1210 (D. Haw. 2015)), NMFS 
began to systematically consider the role of PBR when evaluating the 
effects of M/SI during section 101(a)(5)(A) rulemakings. Previously, in 
1996 shortly after the PBR metric was first introduced, NMFS denied a 
request from the U.S. Coast Guard for an incidental take authorization 
for their vessel and aircraft operations, seemingly solely on the basis 
of the potential for ship strike in relation to PBR. The decision did 
not appear to consider other factors that might also have informed the 
potential

[[Page 66913]]

for ship strike of a North Atlantic right whale in relation to the 
negligible impact standard.
    During the following years and until the Court's decision in 
Conservation Council and the agency issuing the proposed incidental 
take authorization for the Southwest Fisheries Science Center, NMFS 
issued incidental take regulations without referencing PBR. Thereafter, 
however, NMFS began considering and articulating the appropriate role 
of PBR when processing incidental take requests for M/SI under section 
101(a)(5)(A). Consistent with the interpretation of PBR across the rest 
of the agency, NMFS' Permits and Conservation Division has been using 
PBR as a tool to inform the negligible impact analysis under section 
101(a)(5)(A), recognizing that it is not a dispositive threshold that 
automatically determines whether a given amount of M/SI either does or 
does not exceed a negligible impact on the affected species or stock.
    Comment 82: A commenter commented that NMFS failed to adequately 
assess the aggregate effects of all of the Navy's activities included 
in the rule. The commenter alleges that NMFS' lack of analysis of these 
aggregate impacts, which is essential to any negligible impact 
determination, represents a glaring omission from the proposed rule. 
While NMFS states that Level B behavioral harassment (aside from those 
caused by masking effects) involves a stress response that may 
contribute to an animal's allostatic load, it assumes without further 
analysis that any such impacts would be insignificant.
    Response: NMFS did analyze the potential for aggregate effects from 
mortality, injury, masking, habitat effects, energetic costs, stress, 
hearing loss, and behavioral harassment from the Navy's activities in 
reaching the negligible impact determinations. Significant additional 
discussion has been added to the Analysis and Negligible Impact 
Determination section of the final rule to better explain the potential 
for aggregate or cumulative effects on individuals as well as how these 
effects on individuals relate to potential effects on annual rates of 
recruitment and survival for each species or stock.
    In addition, NMFS fully considers the potential for aggregate 
effects from all Navy activities. We also consider UMEs and previous 
environmental impacts, where appropriate, to inform the baseline levels 
of both individual health and susceptibility to additional stressors, 
as well as stock status. Further, the species and stock-specific 
assessments in the Analysis and Negligible Impact Determination section 
(which have been updated and expanded) pull together and address the 
combined mortality, injury, behavioral harassment, and other effects of 
the aggregate HSTT activities (and in consideration of applicable 
mitigation) as well as other information that supports our 
determinations that the Navy activities will not adversely affect any 
species or stocks via impacts on rates of recruitment or survival. We 
refer the reader to the Analysis and Negligible Impact Determination 
section for this analysis.
    Widespread, extensive monitoring since 2006 on Navy ranges that 
have been used for training and testing for decades has demonstrated no 
evidence of population-level impacts. Based on the best available 
research from NMFS and Navy-funded marine mammal studies, there is no 
evidence that ``population-level harm'' to marine mammals, including 
beaked whales, is occurring in the HSTT Study Area. The presence of 
numerous small, resident populations of cetaceans, documented high 
abundances, and populations trending to increase for many marine 
mammals species in the area suggests there are not likely population-
level consequences resulting from decades of ongoing Navy training and 
testing activities. Through the process described in the rule and the 
LOAs, the Navy will work with NMFS to assure that the aggregate or 
cumulative impacts remain at the negligible impact level.
    Regarding the consideration of stress responses, NMFS does not 
assume that the impacts are insignificant. There is currently neither 
adequate data nor mechanism by which the impacts of stress from 
acoustic exposure can be reliably and independently quantified. 
However, stress effects that result from noise exposure likely often 
occur concurrently with behavioral harassment and many are likely 
captured and considered in the quantification of other takes by 
harassment that occur when individuals come within a certain distance 
of a sound source (behavioral harassment, PTS, and TTS).
    Comment 83: Some Commenters asserted that in reaching our MMPA 
negligible impact finding, NMFS did not adequately consider the 
cumulative impacts of the Navy's activities when combined with the 
effects of other non-Navy activities.
    Response: Both the statute and the agency's implementing 
regulations call for analysis of the effects of the applicant's 
activities on the affected species and stocks, not analysis of other 
unrelated activities and their impacts on the species and stocks. That 
does not mean, however, that effects on the species and stocks caused 
by other non-Navy activities are ignored. The preamble for NMFS' 
implementing regulations under section 101(a)(5) (54 FR 40338; 
September 29, 1989) explains in response to comments that the impacts 
from other past and ongoing anthropogenic activities are to be 
incorporated into the negligible impact analysis via their impacts on 
the environmental baseline. Consistent with that direction, NMFS has 
factored into its negligible impact analyses the impacts of other past 
and ongoing anthropogenic activities via their impacts on the baseline 
(e.g., as reflected in the density/distribution and status of the 
species, population size and growth rate, and other relevant stressors 
(such as incidental mortality in commercial fisheries or UMEs)). See 
the Analysis and Negligible Impact Determination section of this rule.
    Our 1989 final rule for the MMPA implementing regulations also 
addressed public comments regarding cumulative effects from future, 
unrelated activities. There we stated that such effects are not 
considered in making findings under section 101(a)(5) concerning 
negligible impact. We indicated that NMFS would consider cumulative 
effects that are reasonably foreseeable when preparing a NEPA analysis 
and also that reasonably foreseeable cumulative effects would be 
considered under section 7 of the ESA for ESA-listed species.
    Also, as described further in the Analysis and Negligible Impact 
Determination section of the final rule, NMFS evaluated the impacts of 
HSTT authorized mortality on the affected stocks in consideration of 
other anticipated human-caused mortality, including the mortality 
predicted in the SARs for other activities along with other NMFS-
permitted mortality (i.e., authorized as part of the Southwest 
Fisheries Science Center rule), using multiple factors, including PBR. 
As described in more detail in the Analysis and Negligible Impact 
Determination section, PBR was designed to identify the maximum number 
of animals that may be removed from a stock (not including natural 
mortalities) while allowing that stock to reach or maintain its OSP and 
is also helpful in informing whether mortality will adversely affect 
annual rates of recruitment or survival in the context of a section 
101(a)(5)(A).

NEPA

    Comment 84: Commenters commented that NMFS cannot rely on

[[Page 66914]]

the Navy's HSTT FEIS/OEIS to fulfill its obligations under NEPA because 
the purpose and need is too narrow and does not support NMFS' MMPA 
action, and therefore the HSTT FEIS/OEIS does not explore a reasonable 
range of alternatives.
    Response: The proposed action at issue is the Navy's proposal to 
conduct testing and training activities in the HSTT Study Area. NMFS is 
a cooperating agency for that proposed action, as it has jurisdiction 
by law and special expertise over marine resources impacted by the 
proposed action, including marine mammals and federally-listed 
threatened and endangered species. Consistent with the regulations 
published by the Council on Environmental Quality (CEQ), it is common 
and sound NEPA practice for NOAA to adopt a lead agency's NEPA analysis 
when, after independent review, NOAA determines the document to be 
sufficient in accordance with 40 CFR 1506.3. Specifically here, NOAA 
must be satisfied that the Navy's EIS adequately addresses the impacts 
of issuing the MMPA incidental take authorization and that NOAA's 
comments and concerns have been adequately addressed. There is no 
requirement in CEQ regulations that NMFS, as a cooperating agency, 
issue a separate purpose and need statement in order to ensure adequacy 
and sufficiency for adoption. Nevertheless, the Navy, in coordination 
with NMFS, has clarified the statement of purpose and need in the HSTT 
FEIS/OEIS to more explicitly acknowledge NMFS' action of issuing an 
MMPA incidental take authorization. NMFS also clarified how its 
regulatory role under the MMPA related to Navy's activities. NMFS' 
early participation in the NEPA process and role in shaping and 
informing analyses using its special expertise ensured that the 
analysis in the HSTT FEIS/OEIS is sufficient for purposes of NMFS' own 
NEPA obligations related to its issuance of incidental take 
authorization under the MMPA.
    Regarding the alternatives, NMFS' early involvement in development 
of the HSTT EIS/OEIS and role in evaluating the effects of incidental 
take under the MMPA ensured that the HSTT DEIS/OEIS would include 
adequate analysis of a reasonable range of alternatives. The HSTT FEIS/
OEIS includes a No Action Alternative specifically to address what 
could happen if NMFS did not issue an MMPA authorization. The other two 
Alternatives address two action options that the Navy could potentially 
pursue while also meeting their mandated Title 10 training and testing 
responsibilities. More importantly, these alternatives fully analyze a 
comprehensive variety of mitigation measures. This mitigation analysis 
supported NMFS' evaluation of our options in potentially issuing an 
MMPA authorization, which, if the authorization may be issued, 
primarily revolves around the appropriate mitigation to prescribe. This 
approach to evaluating a reasonable range of alternatives is consistent 
with NMFS policy and practice for issuing MMPA incidental take 
authorizations. NOAA has independently reviewed and evaluated the EIS, 
including the purpose and need statement and range of alternatives, and 
determined that the HSTT FEIS/OEIS fully satisfies NMFS' NEPA 
obligations related to its decision to issue the MMPA final rule and 
associated LOAs, and we have adopted it.

Endangered Species Act

    Comment 85: A commenter commented that under the ESA NMFS has the 
discretion to impose terms, conditions, and mitigation on any 
authorization. They believe the proposed action clearly affects listed 
whales, sea turtles, and Hawaiian monk seals, triggering the duty to 
consult. The commenter urged NMFS to fully comply with the ESA and 
implement robust reasonable and prudent alternatives and conservation 
measures to avoid harm to endangered species and their habitats.
    Response: NMFS has fully complied with the ESA. The agency 
consulted pursuant to section 7 of the ESA and NMFS' ESA Interagency 
Cooperation Division provided a biological opinion concluded that NMFS' 
action of issuing MMPA incidental take regulations for the Navy HSTT 
activities would not jeopardize the continued existence of any 
threatened or endangered species and nor would it adversely modify any 
designated critical habitat. The biological opinion may be viewed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.

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

    Marine mammal species and their associated stocks that have the 
potential to occur in the HSTT Study Area are presented in Table 13 
along with an abundance estimate, an associated coefficient of 
variation value, and best/minimum abundance estimates. The Navy 
anticipates the take of 39 individual marine mammal species by Level A 
and B harassment incidental to training and testing activities from the 
use of sonar and other transducers, in-water detonations, air guns, and 
impact pile driving/vibratory extraction activities. In addition, the 
Navy requested authorization for ten serious injuries or mortalities 
combined of two marine mammal stocks from explosives, and three takes 
of large whales by serious injury or mortality from vessel strikes over 
the five-year period. Two marine mammal species, the Hawaiian monk seal 
and the Main Hawaiian Islands Insular false killer whale, have critical 
habitat designated under the ESA in the HSTT Study Area (described 
below).
    The species considered but not carried forward for analysis are two 
American Samoa stocks of spinner dolphins--(1) the Kure and Midway 
stock and (2) the Pearl and Hermes stock. There is no potential for 
overlap with any stressors from Navy activities and therefore there 
would be no incidental takes, in which case, these stocks are not 
considered further.
    We presented a detailed discussion of marine mammals and their 
occurrence in the planned action area, inclusive of ESA-designated 
critical habitat, BIAs, National Marine Sanctuaries, and unusual 
mortality events (UMEs) in our Federal Register notice of proposed 
rulemaking (83 FR 29872; June 26, 2018); please see that notice of 
proposed rulemaking or the Navy's application for more information. 
There have been no changes or new information on BIAs and National 
Marine Sanctuaries since publication of the proposed rule; therefore, 
they are not discussed further. Additional information on certain ESA-
designated critical habitat and UMEs has become available and so both 
of these topics are discussed following Table 13.

[[Page 66915]]



                                              Table 13--Marine Mammal Occurrence Within the HSTT Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                 Status                                                  Stock abundance
         Common name            Scientific name        Stock      ------------------------------------    Occurrence        Seasonal       (CV)/minimum
                                                                         MMPA               ESA                             absence         population
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale...................  Balaenoptera      Eastern North     Strategic,        Endangered......  Southern         ...............  1,647 (0.07)/
                                musculus.         Pacific.          Depleted.                           California.                       1,551
                                                 Central North     Strategic,        Endangered......  Hawaii.........  Summer.........  133 (1.09)/63
                                                  Pacific.          Depleted.
Bryde's whale................  Balaenoptera      Eastern Tropical  ................  ................  Southern         ...............  unknown
                                brydei/edeni.     Pacific.                                              California.
                                                 Hawaii..........  ................  ................  Hawaii.........  ...............  1,751 (0.29)/
                                                                                                                                          1,378
Fin whale....................  Balaenoptera      CA/OR/WA........  Strategic,        Endangered......  Southern         ...............  9,029 (0.12)/
                                physalus.                           Depleted.                           California.                       8,127
                                                 Hawaii..........  Strategic,        Endangered......  Hawaii.........  Summer.........  154 (1.05)/75
                                                                    Depleted.
Gray whale...................  Eschrichtius      Eastern North     ................  ................  Southern         ...............  26,960
                                robustus.         Pacific.                                              California.                      (0.05)/25,849
                                                 Western North     Strategic,        Endangered......  Southern         ...............  175
                                                  Pacific.          Depleted.                           California.                      (0.05)/167
Humpback whale...............  Megaptera         CA/OR/WA........  Strategic,        Threatened/.....  Southern         ...............  2,900
                                novaeangliae.                       Depleted.        Endangered \1\..   California.                      (0.03)/2,784
                                                 Central North     Strategic.......  ................  Hawaii.........  Summer.........  10,103
                                                  Pacific.                                                                               (0.30)/7,891
Minke whale..................  Balaenoptera      CA/OR/WA........  ................  ................  Southern         ...............  636
                                acutorostrata.                                                          California.                      (0.72)/369
                                                 Hawaii..........  ................  ................  Hawaii.........  Summer.........  unknown
Sei whale....................  Balaenoptera      Eastern North     Strategic,        Endangered......  Southern         ...............  519
                                borealis.         Pacific.          Depleted.                           California.                      (0.4)/374
                                                 Hawaii..........  Strategic,        Endangered......  Hawaii.........  Summer.........  391
                                                                    Depleted.                                                            (0.90)/204
Sperm whale..................  Physeter          CA/OR/WA........  Strategic,        Endangered......  Southern         ...............  1,997
                                macrocephalus.                      Depleted.                           California.                      (0.57)/1,270
                                                 Hawaii..........  Strategic,        Endangered......  Hawaii.........  ...............  4,559
                                                                    Depleted.                                                            (0.33)/3,478
Pygmy sperm whale............  Kogia breviceps.  CA/OR/WA........  ................  ................  Southern         Winter and Fall  4,111
                                                                                                        California.                      (1.12)/1,924
                                                 Hawaii..........  ................  ................  Hawaii.........  ...............  unknown
Dwarf sperm whale............  Kogia sima......  CA/OR/WA........  ................  ................  Southern         ...............  unknown
                                                                                                        California.
                                                 Hawaii..........  ................  ................  Hawaii.........  ...............  unknown
Baird's beaked whale.........  Berardius         CA/OR/WA........  ................  ................  Southern         ...............  2,697
                                bairdii.                                                                California.                      (0.6)/1,633
Blainville's beaked whale....  Mesoplodon        Hawaii..........  ................  ................  Hawaii.........  ...............  2,105
                                densirostris.                                                                                            (1.13)/980
Cuvier's beaked whale........  Ziphius           CA/OR/WA........  ................  ................  Southern         ...............  3,274
                                cavirostris.                                                            California.                      (0.67)/2,059
                                                 Hawaii..........  ................  ................  Hawaii.........  ...............  723
                                                                                                                                         0.69/428
Longman's beaked whale.......  Indopacetus       Hawaii..........  ................  ................  Hawaii.........  ...............  7,619
                                pacificus.                                                                                               (0.66)/4,592
Mesoplodon beaked whales.....  Mesoplodon spp..  CA/OR/WA........  ................  ................  Southern         ...............  3,044
                                                                                                        California.                      (0.54)/1,967
Common Bottlenose dolphin....  Tursiops          California        ................  ................  Southern         ...............  453
                                truncatus.        Coastal.                                              California.                      (0.06)/346
                                                 CA/OR/WA          ................  ................  Southern         ...............  1,924
                                                  Offshore.                                             California.                      (0.54)/1,255
                                                 Hawaii Pelagic..  ................  ................  Hawaii.........  ...............  21,815
                                                                                                                                         (0.57)/13.957
                                                 Kauai and Niihau  ................  ................  Hawaii.........  ...............  NA
                                                                                                                                         NA/97
                                                 Oahu............  ................  ................  Hawaii.........  ...............  NA
                                                 4-Islands.......  ................  ................  Hawaii.........  ...............  NA
                                                 Hawaii Island...  ................  ................  Hawaii.........  ...............  NA
                                                                                                                                         NA/91
False killer whale...........  Pseudorca         Main Hawaiian     Strategic,        Endangered......  Hawaii.........  ...............  167
                                crassidens.       Islands Insular.  Depleted.                                                            (0.14)/149

[[Page 66916]]

 
                                                 Hawaii Pelagic..  ................  ................  Hawaii.........  ...............  1,540
                                                                                                                                         (0.66)/928
                                                 Northwestern      ................  ................  Hawaii.........  ...............  617
                                                  Hawaiian                                                                               (1.11)/290
                                                  Islands.
Fraser's dolphin.............  Lagenodelphis     Hawaii..........  ................  ................  Hawaii.........  ...............  51,491
                                hosei.                                                                                                   (0.66)/31,034
Killer whale.................  Orcinus orca....  Eastern North     ................  ................  Southern         ...............  300
                                                  Pacific                                               California.                      (0.1)/276
                                                  Offshore.
                                                 Eastern North     ................  ................  Southern         ...............  243
                                                  Pacific                                               California.                      unknown/243
                                                  Transient/West
                                                  Coast Transient
                                                  \2\.
                                                 Hawaii..........  ................  ................  Hawaii.........  ...............  146
                                                                                                                                         (0.96)/74
Long-beaked common dolphin...  Delphinus         California......  ................  ................  Southern         ...............  101,305
                                capensis.                                                               California.                      (0.49)/68,432
Melon-headed whale...........  Peponocephala     Hawaiian Islands  ................  ................  Hawaii.........  ...............  8,666
                                electra.                                                                                                 (1.00)/4,299
                                                 Kohala Resident.  ................  ................  Hawaii.........  ...............  447
                                                                                                                                         (0.12)/404
Northern right whale dolphin.  Lissodelphis      CA/OR/WA........  ................  ................  Southern         ...............  26,556
                                borealis.                                                               California.                      (0.44)/18,608
Pacific white-sided dolphin..  Lagenorhynchus    CA/OR/WA........  ................  ................  Southern         ...............  26,814
                                obliquidens.                                                            California.                      (0.28)/21,195
Pantropical spotted dolphin..  Stenella          Oahu............  ................  ................  Hawaii.........  ...............  unknown
                                attenuata.
                                                 4-Islands.......  ................  ................  Hawaii.........  ...............  unknown
                                                 Hawaii Island...  ................  ................  Hawaii.........  ...............  unknown
                                                 Hawaii Pelagic..  ................  ................  Hawaii.........  ...............  55,795
                                                                                                                                         (0.40)/40,338
Pygmy killer whale...........  Feresa attenuata  Tropical........  ................  ................  Southern         Winter & Spring  unknown
                                                                                                        California.
                                                 Hawaii..........  ................  ................  Hawaii.........  ...............  10,640
                                                                                                                                         (0.53)/6,998
Risso's dolphins.............  Grampus griseus.  CA/OR/WA........  ................  ................  Southern         ...............  6,336
                                                                                                        California.                      (0.32)/4,817
                                                 Hawaii..........  ................  ................  Hawaii.........  ...............  11,613
                                                                                                                                         (0.43)/8,210
Rough-toothed dolphin........  Steno             NSD \3\.........  ................  ................  Southern         ...............  unknown
                                bredanensis.                                                            California.
                                                 Hawaii..........  ................  ................  Hawaii.........  ...............  72,528
                                                                                                                                         (0.39)/52,833
Short-beaked common dolphin..  Delphinus         CA/OR/WA........  ................  ................  Southern         ...............  969,861
                                delphis.                                                                California.                      (0.17)/839,325
Short-finned pilot whale.....  Globicephala      CA/OR/WA........  ................  ................  Southern         ...............  836
                                macrorhynchus.                                                          California.                      (0.79)/466
                                                 Hawaii..........  ................  ................  Hawaii.........  ...............  19,503
                                                                                                                                         (0.49)/13,197
Spinner dolphin..............  Stenella          Hawaii Pelagic..  ................  ................  Hawaii.........  ...............  unknown
                                longirostris.
                                                 Hawaii Island...  ................  ................  Hawaii.........  ...............  665
                                                                                                                                         (0.09)/617
                                                 Oahu and 4-       ................  ................  Hawaii.........  ...............  NA
                                                  Islands.
                                                 Kauai and Niihau  ................  ................  Hawaii.........  ...............  NA
                                                 Kure and Midway.  ................  ................  Hawaii.........  ...............  unknown
                                                 Pearl and Hermes  ................  ................  Hawaii.........  ...............  unknown
Striped dolphin..............  Stenella          CA/OR/WA........  ................  ................  Southern         ...............  29,211
                                coeruleoalba.                                                           California.                      (0.20)/24,782

[[Page 66917]]

 
                                                 Hawaii..........  ................  ................  Hawaii.........  ...............  61,021
                                                                                                                                         (0.38)/44,922
Dall's porpoise..............  Phocoenoides      CA/OR/WA........  ................  ................  Southern         ...............  25,750
                                dalli.                                                                  California.                      (0.45)/17,954
Harbor seal..................  Phoca vitulina..  California......  ................  ................  Southern         ...............  30,968
                                                                                                        California.                      NA/27,348
Hawaiian monk seal...........  Neomonachus       Hawaii..........  Strategic,        Endangered......  Hawaii.........  ...............  1,415
                                schauinslandi.                      Depleted.                                                            (0.03)/1,384
Northern elephant seal.......  Mirounga          California......  ................  ................  Southern         ...............  179,000
                                angustirostris.                                                         California.                      NA/81,368
California sea lion..........  Zalophus          U.S. Stock......  ................  ................  Southern         ...............  257,606
                                californianus.                                                          California.                      NA/233,515
Guadalupe fur seal...........  Arctocephalus     Mexico to         Strategic,        Threatened......  Southern         ...............  20,000
                                townsendi.        California.       Depleted.                           California.                      NA/15,830
Northern fur seal............  Callorhinus       California......  ................  ................  Southern         ...............  14,050
                                ursinus.                                                                California.                      NA/7,524
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The two humpback whale Distinct Population Segments making up the California, Oregon, and Washington stock present in Southern California are the
  Mexico Distinct Population Segment, listed under the ESA as Threatened, and the Central America Distinct Population Segment, which is listed under the
  ESA as Endangered.
\2\ This stock is mentioned briefly in the Pacific Stock Assessment Report (Carretta et al., 2017) and referred to as the ``Eastern North Pacific
  Transient'' stock; however, the Alaska Stock Assessment Report contains assessments of all transient killer whale stocks in the Pacific and the Alaska
  Stock Assessment Report refers to this same stock as the ``West Coast Transient'' stock (Muto et al., 2017).
\3\ NSD--No stock designation. Rough-toothed dolphin has a range known to include the waters off Southern California, but there is no recognized stock
  or data available for the U.S. West Coast.

    The proposed rule (83 FR 29909, June 26, 2018) includes a 
description of ESA designated critical habitat, BIAs, National Marine 
Sanctuaries, and unusual mortality events that are applicable in the 
HSTT Study area and that material remains applicable and is not 
repeated here. However, we do include information where anything has 
changed. In this case, since the proposed rule was published, ESA 
designated critical habitat for main Hawaiian Islands insular false 
killer whales was finalized and new information regarding the 
California sea lion UME became available.
    Critical habitat for the ESA-listed Main Hawaiian Islands insular 
false killer whale DPS was finalized in July 2018 (83 FR 35062; July 
24, 2018) designating waters from the 45 m depth contour to the 3,200 m 
depth contour around the main Hawaiian Islands from Niihau east to 
Hawaii. This designation does not include most bays, harbors, or 
coastal in-water structures. NMFS excluded 14 areas (one area, with two 
sites, for the Bureau of Ocean Energy Management and 13 areas requested 
by the Navy) from the critical habitat designation because it was 
determined that the benefits of exclusion outweighed the benefits of 
inclusion, and exclusion would not result in extinction of the species. 
In addition, two areas, the Ewa Training Minefield and the Naval 
Defensive Sea Area, were ineligible for designation because they are 
managed under the Joint Base Pearl Harbor-Hickam Integrated Natural 
Resources Management Plan that was found to benefit main Hawaiian 
Islands insular false killer whales. The total area designated was 
approximately 45,504 km\2\ (17,564 mi\2\) of marine habitat and the 
designation stresses the importance of protecting: adequate space for 
movement and use; prey species of sufficient quantity, quality, and 
availability to support growth and reproduction; waters free of harmful 
types and amounts of pollutants; and sound levels that would not 
significantly impair false killer whale use or occupancy.
    Regarding the California sea lion UME, although this UME has not 
been closed, NMFS staff recently confirmed that the mortality of pups 
and yearlings returned to normal in 2017 and 2018 and they plan to 
present it to the Working Group to discuss closure by the end of 2018 
(Deb Fauquier, pers. comm.). Please refer to the proposed rule (83 FR 
29872; June 26, 2018) and NMFS' website at https://www.fisheries.noaa.gov/national/marine-life-distress/2013-2017-california-sea-lion-unusual-mortality-event-california for more 
information on this UME.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    We provided a summary and discussion of the potential effects of 
the specified activity on marine mammals and their habitat in our 
Federal Register notice of proposed rulemaking (83 FR 29872; June 26, 
2018). In the Potential Effects of Specified Activities on Marine 
Mammals and Their Habitat section of the proposed rule, NMFS provided a 
description of the ways marine mammals may be affected by these 
activities in the form of serious injury or mortality, physical trauma, 
sensory impairment (permanent and temporary threshold shift and 
acoustic masking), physiological responses (particular stress 
responses), behavioral disturbance, or habitat effects. Therefore, we 
do not reprint the information here but refer the reader to that 
document. For additional summary and discussion of recent scientific 
studies not included in the proposed rulemaking, we direct the reader 
to the HSTT FEIS/OEIS (Chapter 3, Section 3.7 Marine Mammals, http://www.hstteis.com/), which NMFS participated in the development of via 
our cooperating agency status and adopted to meet our NEPA 
requirements. We highlight several studies below, but direct the reader 
to the HSTT FEIS/OEIS for a full compilation. As noted above, NMFS has 
reviewed and accepted the Navy's compilation and interpretation of the 
best available science contained in the HSTT FEIS/OEIS. More 
specifically, we have independently reviewed the more recent studies 
that were not included in NMFS' proposed rule, have concluded that the 
Navy's descriptions and interpretations of those studies in the

[[Page 66918]]

FEIS/OEIS are accurate, and have taken those studies into consideration 
in our analyses that inform our negligible impact determinations. 
Importantly, we note that none of the newer information highlighted 
here or in the HSTT FEIS/OEIS affects our analysis in a manner that 
changes our determinations under the MMPA from the proposed rule.
    The Acoustic Technical Guidance (NMFS, 2018), 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. New data on 
killer whale hearing (Branstetter et al., 2017), harbor porpoise 
hearing (Kastelein et al., 2017a), harbor porpoise threshold shift (TS) 
in response to airguns (Kastelein et al., 2017b) and mid-frequency 
sonar (Kastelein et al., 2017c), and harbor seal TS in response to 
pile-driving sounds (Kastelein et al., 2018) are consistent with data 
included and thresholds presented in the Acoustic Technical Guidance.
    Recent studies with captive odontocete species (bottlenose dolphin, 
harbor porpoise, beluga, and false killer whale) have observed 
increases in hearing threshold levels when individuals received a 
warning sound prior to exposure to a relatively loud sound (Finneran, 
2018; Nachtigall and Supin, 2013, 2015; Nachtigall et al., 2016a,b,c; 
Nachtigall, et al., 2018). These studies suggest that captive animals 
have a mechanism to reduce hearing sensitivity prior to impending loud 
sounds. Hearing change was observed to be frequency dependent and 
Finneran (2018) suggests hearing attenuation occurs within the cochlea 
or auditory nerve. Based on these observations on captive odontocetes, 
the authors suggest that wild animals may have a mechanism to self-
mitigate the impacts of noise exposure by dampening their hearing 
during prolonged exposures of loud sound, or if conditioned to 
anticipate intense sounds (Finneran, 2018, Nachtigall et al., 2018).
    Recent reviews have synthesized data from experimental studies 
examining marine mammal behavioral response to anthropogenic sound, and 
have documented large variances in individual behavioral responses to 
anthropogenic sound both within and among marine mammal species. These 
reviews highlight the importance of the exposure context (e.g., 
behavioral state, presence of other animals and social relationships, 
prey abundance, distance to source, presence of vessels, environmental 
parameters, etc.) in determining or predicting a behavioral response. 
As described in the proposed rule, in a review of experimental field 
studies to measure behavioral responses of cetaceans to sonar, Southall 
et al. (2016) observed that some individuals of different species 
display clear yet varied responses (some of which have negative 
implications), while others appear to tolerate high levels. Results 
from the studies they investigated demonstrate that responses are 
highly variable and may not be fully predictable with simple acoustic 
exposure metrics (e.g., received sound level). Rather, differences 
among species and individuals along with contextual aspects of exposure 
(e.g., behavioral state) appear to affect response probability 
(Southall et al., 2016). Dunlop et al. (2018) combined data from the 
BRAHSS (Behavioural Response of Australian Humpback whales to Seismic 
Surveys) studies designed to examine the behavioral responses of 
migrating humpback whales to various seismic array sources to develop a 
dose-response model. The model accounted for other variables such as 
presence of the vessel, array towpath relative to the migration, and 
social and environmental parameters. Authors observed that whales were 
more likely to avoid the airgun or array (defined by increasing their 
distance from the source) when they were exposed to sounds greater than 
130 dB re 1 [mu]Pa\2\[middot]s and they were within 4 km of the source 
(Dunlop et al., 2018). At sound exposure levels of 150-155 dB re 1 
[mu]Pa\2\[middot]s and less than 2.5 km from the source the model 
predicted a 50 percent probability of response (Dunlop et al., 2018). 
However, it was not possible to estimate the maximum response threshold 
as at the highest received levels of 160-170 dB re 1 
[mu]Pa\2\[middot]s, a small number of whales moving rapidly and close 
to the source did not exhibit an avoidance response as defined by the 
study (Dunlop et al., 2018).

Estimated Take of Marine Mammals

    This section indicates the number of takes that NMFS is 
authorizing, which are based on the amount of take that NMFS 
anticipates could occur 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 with one limited exception, agrees 
that the methods the Navy put forth in their application to estimate 
take (including the model, thresholds, and density estimates), and the 
resulting numbers are based on the best available science and 
appropriate for authorization. As noted elsewhere, additional 
discussion and subsequent analysis led both NMFS and the Navy, in 
coordination, to conclude that different take estimates for serious 
injury or mortality from vessel strikes were appropriate, and where 
those numbers differ from the Navy's application or our proposed rule, 
NMFS has explicitly described our rationale and indicated what we 
consider an appropriate number of takes.
    Takes are predominantly in the form of harassment, but a small 
number of serious injuries or mortalities are also authorized. 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 
behavioral patterns, including, but not limited to, migration, 
surfacing, nursing, breeding, feeding, or sheltering, to a point where 
such behavioral patterns are abandoned or significantly altered (Level 
B harassment).
    Authorized takes would primarily be in the form of Level B 
harassment, as use of the acoustic and explosive sources (i.e., sonar, 
air guns, pile driving, explosives) is more likely to result in the 
disruption of natural behavioral patterns to a point where they are 
abandoned or significantly altered (as defined specifically in the 
paragraph above, but referred to generally as behavioral disruption) or 
TTS for marine mammals than other forms of take. There is also the 
potential for Level A harassment, however, in the form of auditory 
injury and/or tissue damage (the latter from explosives only) to result 
from exposure to the sound sources utilized in training and testing 
activities. Lastly, a limited number of serious injuries or mortalities 
could occur for California sea lion and short-beaked common dolphin (10 
mortalities total between the two species over a five year period) from 
explosives, and no more than three serious injuries or mortalities 
total (over the five-year period) of large whales through vessel 
collisions. Although we analyze the impacts of these potential serious 
injuries or mortalities that are authorized, the required mitigation 
and monitoring measures are expected to minimize the likelihood that 
ship strike or these high level explosive exposures (and the associated 
serious injury or mortality) actually occur.

[[Page 66919]]

    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 and present 
the take estimate.

Acoustic Thresholds

    Using the best available science, NMFS, in coordination with the 
Navy, has established acoustic thresholds that identify the most 
appropriate received level of underwater sound above which marine 
mammals exposed to these sound sources could be reasonably expected to 
experience a disruption in behavior patterns to a point where they are 
abandoned or significantly altered, or to incur TTS (equated to Level B 
harassment) or PTS of some degree (equated to Level A harassment). 
Thresholds have also been developed to identify the pressure levels 
above which animals may incur non-auditory injury from exposure to 
pressure waves from explosive detonation.
    Despite the quickly evolving science, there are still challenges in 
quantifying expected behavioral responses that qualify as Level B 
harassment, especially where the goal is to use one or two predictable 
indicators (e.g., received level and distance) to predict responses 
that are also driven by additional factors that cannot be easily 
incorporated into the thresholds (e.g., context). So, while the new 
Level B behavioral harassment thresholds have been refined here to 
better consider the best available science (e.g., incorporating both 
received level and distance), they also still, accordingly, have some 
built-in conservative factors to address the challenge noted. For 
example, while duration of observed responses in the data are now 
considered in the thresholds, some of the responses that are informing 
take thresholds are of a very short duration, such that it is possible 
some of these responses might not always rise to the level of 
disrupting behavior patterns to a point where they are abandoned or 
significantly altered. We describe the application of this Level B 
behavioral harassment threshold as identifying the maximum number of 
instances in which marine mammals could be reasonably expected to 
experience a disruption in behavior patterns to a point where they are 
abandoned or significantly altered. In summary, we believe these Level 
B behavioral harassment thresholds are the most appropriate method for 
predicting Level B behavioral harassment given the best available 
science and the associated uncertainty. Hearing Impairment (TTS/PTS and 
Tissues Damage and Mortality)

Non-Impulsive and Impulsive

    NMFS' Acoustic Technical Guidance (NMFS, 2018) identifies dual 
criteria to assess auditory injury (Level A harassment) to five 
different marine mammal groups (based on hearing sensitivity) as a 
result of exposure to noise from two different types of sources 
(impulsive or non-impulsive). The Acoustic Technical Guidance also 
identifies criteria to predict TTS, which is not considered injury and 
falls into the Level B harassment category. The Navy's planned activity 
includes the use of non-impulsive (sonar, vibratory pile driving/
removal) and impulsive (explosives, airguns, impact pile driving) 
sources.
    These thresholds (Tables 14-15) were developed by compiling and 
synthesizing the best available science and soliciting input multiple 
times from both the public and peer reviewers. The references, 
analysis, and methodology used in the development of the thresholds are 
described in Acoustic Technical Guidance, which may be accessed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

 Table 14--Acoustic Thresholds Identifying the Onset of TTS and PTS for
        Non-Impulsive Sound Sources by Functional Hearing Groups
------------------------------------------------------------------------
                                                Non-impulsive
                                   -------------------------------------
     Functional hearing group       TTS threshold SEL  PTS threshold SEL
                                        (weighted)         (weighted)
------------------------------------------------------------------------
Low-Frequency Cetaceans...........                179                199
Mid-Frequency Cetaceans...........                178                198
High-Frequency Cetaceans..........                153                173
Phocid Pinnipeds (Underwater).....                181                201
Otarid Pinnipeds (Underwater).....                199                219
------------------------------------------------------------------------
Note: SEL thresholds in dB re 1 [mu]Pa\2\s.

    Based on the best available science, the Navy (in coordination with 
NMFS) used the acoustic and pressure thresholds indicated in Table 15 
to predict the onset of TTS, PTS, tissue damage, and mortality for 
explosives (impulsive) and other impulsive sound sources.

           Table 15--Onset of TTS, PTS, Tissue Damage, and Mortality Thresholds for Marine Mammals for Explosives and Other Impulsive Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                 Mean onset slight  Mean onset slight      Mean onset
     Functional hearing group             Species             Onset TTS           Onset PTS       GI tract injury      lung injury         mortality
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans..........  All mysticetes......  168 dB SEL          183 dB SEL          237 dB Peak SPL..  Equation 1.......  Equation 2.
                                                          (weighted) or 213   (weighted) or 219
                                                          dB Peak SPL.        dB Peak SPL.

[[Page 66920]]

 
Mid-frequency cetaceans..........  Most delphinids,      170 dB SEL          185 dB SEL          237 dB Peak SPL..
                                    medium and large      (weighted) or 224   (weighted) or 230
                                    toothed whales.       dB Peak SPL.        dB Peak SPL.
High-frequency cetaceans.........  Porpoises and Kogia   140 dB SEL          155 dB SEL          237 dB Peak SPL..
                                    spp.                  (weighted) or 196   (weighted) or 202
                                                          dB Peak SPL.        dB Peak SPL.
Phocidae.........................  Harbor seal,          170 dB SEL          185 dB SEL          237 dB Peak SPL..
                                    Hawaiian monk seal,   (weighted) or 212   (weighted) or 218
                                    Northern elephant     dB Peak SPL.        dB Peak SPL.
                                    seal.
Otariidae........................  California sea lion,  188 dB SEL          203 dB SEL          237 dB Peak SPL..
                                    Guadalupe fur seal,   (weighted) or 226   (weighted) or 232
                                    Northern fur seal.    dB Peak SPL.        dB Peak SPL.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
Equation 1: 47.5M1/3 (1+[DRm/10.1])1/6 Pa-sec.
Equation 2: 103M1/3 (1+[DRm/10.1])1/6 Pa-sec.
M = mass of the animals in kg.
DRm = depth of the receiver (animal) in meters.
SPL = sound pressure level.

Impulsive--Air Guns and Impact Pile Driving
    Impact pile driving produces impulsive noise; therefore, the 
criteria used to assess the onset of TTS and PTS are identical to those 
used for air guns, as well as explosives (see Table 15 above) (see 
Hearing Loss from Air Guns in Chapter 6 Section 6.4.3.1, Methods for 
Analyzing Impacts from air guns in the Navy's rulemaking/LOA 
application). Refer to the Criteria and Thresholds for U.S. Navy 
Acoustic and Explosive Effects Analysis (Phase III) report (U.S. 
Department of the Navy, 2017c) for detailed information on how the 
criteria and thresholds were derived.
Non-Impulsive--Sonar and Vibratory Pile Driving/Removal
    Vibratory pile removal (that will be used during the ELCAS) creates 
continuous non-impulsive noise at low source levels for a short 
duration. Therefore, the criteria used to assess the onset of TTS and 
PTS due to exposure to sonars (non-impulsive, see Table 14 above) are 
also used to assess auditory impacts to marine mammals from vibratory 
pile driving (see Hearing Loss from Sonar and Other Transducers in 
Chapter 6, Section 6.4.2.1, Methods for Analyzing Impacts from Sonars 
and Other Transducers in the Navy's rulemaking/LOA application). Refer 
to the Criteria and Thresholds for U.S. Navy Acoustic and Explosive 
Effects Analysis (Phase III) report (U.S. Department of the Navy, 
2017c) for detailed information on how the criteria and thresholds were 
derived. Non-auditory injury (i.e., other than PTS) and mortality from 
sonar and other transducers is so unlikely as to be discountable under 
normal conditions for the reasons explained in the proposed rule under 
Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat section--Acoustically Mediated Bubble Growth and other 
Pressure-related Injury and is therefore not considered further in this 
analysis.

Behavioral Harassment

    Though significantly driven by received level, the onset of Level B 
harassment by behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source (e.g., frequency, predictability, duty cycle), the environment 
(e.g., bathymetry), and the receiving animals (hearing, motivation, 
experience, demography, behavioral context) and can be difficult to 
predict (Ellison et al., 2011; Southall et al., 2007). Based on what 
the available science indicates and the practical need to use 
thresholds based on a factor, or factors, that are both predictable and 
measurable for most activities, NMFS uses generalized acoustic 
thresholds based primarily on received level (and distance in some 
cases) to estimate the onset of Level B behavioral harassment.
Air Guns and Pile Driving
    For air guns and pile driving, NMFS predicts that marine mammals 
are likely to be taken by Level B behavioral harassment when exposed to 
underwater anthropogenic noise above received levels of 120 dB re 1 
[mu]Pa (rms) for continuous (e.g., vibratory pile-driving, drilling) 
and above 160 dB re 1 [mu]Pa (rms) for non-explosive impulsive (e.g., 
seismic air guns) or intermittent (e.g., scientific sonar) sources. To 
estimate Level B behavioral harassment from air guns, the existing NMFS 
Level B harassment threshold of 160 dB re 1 [micro]Pa (rms) is used. 
The rms calculation for air guns is based on the duration defined by 90 
percent of the cumulative energy in the impulse.
    The existing NMFS Level B harassment thresholds were also applied 
to estimate Level B behavioral harassment from impact and vibratory 
pile driving (Table 16).

    Table 16--Pile Driving Level B Harassment Thresholds Used in This
      Analysis To Predict Behavioral Responses From Marine Mammals
------------------------------------------------------------------------
    Pile driving criteria (SPL, dB re 1     Level B harassment threshold
                  [mu]Pa)                  -----------------------------
-------------------------------------------
           Underwater vibratory                   Underwater impact
------------------------------------------------------------------------
120 dB rms................................  160 dB rms.
------------------------------------------------------------------------
Notes: Root mean square calculation for impact pile driving is based on
  the duration defined by 90 percent of the cumulative energy in the
  impulse. Root mean square for vibratory pile driving is calculated
  based on a representative time series long enough to capture the
  variation in levels, usually on the order of a few seconds. dB:
  decibel; dB re 1 [micro]Pa: decibel referenced to 1 micropascal; rms:
  root mean square.

Sonar
    As noted above, the Navy coordinated with NMFS to propose Level B 
behavioral harassment thresholds specific to their military readiness

[[Page 66921]]

activities utilizing active sonar. Behavioral response criteria are 
used to estimate the number of animals that may exhibit a behavioral 
response to sonar and other transducers. The way the criteria were 
derived is discussed in detail in the Criteria and Thresholds for U.S. 
Navy Acoustic and Explosive Effects Analysis (Phase III) report (U.S. 
Department of the Navy, 2017c). Developing the new Level B harassment 
behavioral criteria involved multiple steps. All peer-reviewed 
published behavioral response studies conducted both in the field and 
on captive animals were examined in order to understand the breadth of 
behavioral responses of marine mammals to sonar and other transducers. 
NMFS has carefully reviewed the Navy's Level B behavioral thresholds 
and establishment of cutoff distances for the species, and agrees that 
it is the best available science and is the appropriate method to use 
at this time for determining impacts to marine mammals from sonar and 
other transducers and for calculating take and to support the 
determinations made in the final rule.
    As noted above, marine mammal responses to sound (some of which are 
considered disturbances that rise to the level of a take) are highly 
variable and context specific, i.e., they are affected by differences 
in acoustic conditions; differences between species and populations; 
differences in gender, age, reproductive status, or social behavior; or 
other prior experience of the individuals. This means that there is 
support for considering alternative approaches for estimating Level B 
behavioral harassment. Although the statutory definition of Level B 
harassment for military readiness activities means that a natural 
behavior pattern of a marine mammal is significantly altered or 
abandoned, the current state of science for determining those 
thresholds is somewhat unsettled.
    In its analysis of impacts associated with sonar acoustic sources 
(which was coordinated with NMFS), the Navy used an updated 
conservative approach that likely overestimates the number of takes by 
Level B harassment due to behavioral disturbance and response. Many of 
the behavioral responses identified using the Navy's quantitative 
analysis are most likely to be of moderate severity as described in the 
Southall et al. (2007) behavioral response severity scale. These 
``moderate'' severity responses were considered significant if they 
were sustained for the duration of the exposure or longer. Within the 
Navy's quantitative analysis, many reactions are predicted from 
exposure to sound that may exceed an animal's Level B behavioral 
harassment threshold for only a single exposure (a few seconds) to 
several minutes, and it is likely that some of the resulting estimated 
behavioral responses that are counted as Level B harassment would not 
constitute ``significantly altering or abandoning natural behavioral 
patterns.'' The Navy and NMFS have used the best available science to 
address the challenging differentiation between significant and non-
significant behavioral reactions (i.e., whether the behavior has been 
abandoned or significantly altered such that it qualifies as 
harassment), but have erred on the cautious side where uncertainty 
exists (e.g., counting these lower duration reactions as take), which 
likely results in some degree of overestimation of Level B behavioral 
harassment. We consider application of this Level B behavioral 
harassment threshold, therefore, as identifying the maximum number of 
instances in which marine mammals could be reasonably expected to 
experience a disruption in behavior patterns to a point where they are 
abandoned or significantly altered (i.e., Level B harassment). Because 
this is the most appropriate method for estimating Level B harassment 
given the best available science and uncertainty on the topic, it is 
these numbers of Level B harassment by behavioral disturbance that are 
analyzed in the Analysis and Negligible Impact Determination section 
and are being authorized.
    In the Navy's acoustic impact analyses during Phase II, the 
likelihood of Level B behavioral harassment in response to sonar and 
other transducers was based on a probabilistic function (termed a 
behavioral response function--BRF), that related the likelihood (i.e., 
probability) of a behavioral response (at the level of a Level B 
harassment) to the received SPL. The BRF was used to estimate the 
percentage of an exposed population that is likely to exhibit Level B 
harassment due to altered behaviors or behavioral disturbance at a 
given received SPL. This BRF relied on the assumption that sound poses 
a negligible risk to marine mammals if they are exposed to SPL below a 
certain ``basement'' value. Above the basement exposure SPL, the 
probability of a response increased with increasing SPL. Two BRFs were 
used in Navy acoustic impact analyses: BRF1 for mysticetes and BRF2 for 
other species. BRFs were not used for beaked whales during Phase II 
analyses. Instead, a step function at an SPL of 140 dB re 1 [mu]Pa was 
used for beaked whales as the threshold to predict Level B harassment 
by behavioral disturbance. Of note, a separate step function at an SPL 
of 120 dB re 1 [mu]Pa was used for harbor porpoises in the 2013-2018 
rule, but there are no harbor porpoises in the HSTT Study Area (and 
Dall's porpoises do not have the same behavioral sensitivities), so 
harbor porpoises are not discussed further.
    Developing the new Level B behavioral harassment criteria for Phase 
III involved multiple steps: All available behavioral response studies 
conducted both in the field and on captive animals were examined to 
understand the breadth of behavioral responses of marine mammals to 
sonar and other transducers. Six behavioral response field studies with 
observations of 14 different marine mammal species reactions to sonar 
or sonar-like signals and 6 captive animal behavioral studies with 
observations of 8 different species reactions to sonar or sonar-like 
signals were used to provide a robust data set for the derivation of 
the Navy's Phase III marine mammal behavioral response criteria. All 
behavioral response research that has been published since the 
derivation of the Navy's Phase III criteria (c.a. December 2016) has 
been examined and is consistent with the current behavioral response 
functions. Marine mammal species were placed into behavioral criteria 
groups based on their known or suspected behavioral sensitivities to 
sound. In most cases these divisions were driven by taxonomic 
classifications (e.g., mysticetes, pinnipeds). The data from the 
behavioral studies were analyzed by looking for significant responses, 
or lack thereof, for each experimental session.
    The Navy used cutoff distances beyond which the potential of 
significant behavioral responses (and therefore Level B harassment) is 
considered to be unlikely (see Table 17 below). This was determined by 
examining all available published field observations of behavioral 
reactions to sonar or sonar-like signals that included the distance 
between the sound source and the marine mammal. The longest distance, 
rounded up to the nearest 5-km increment, was chosen as the cutoff 
distance for each behavioral criteria group (i.e., odontocetes, 
mysticetes, pinnipeds, and beaked whales). For animals within the 
cutoff distance, a behavioral response function based on a received SPL 
as presented in Chapter 3, Section 3.1.0 of the Navy's rulemaking/LOA 
application was used to predict the probability of a potential 
significant behavioral response. For training and testing events that 
contain multiple platforms or tactical sonar sources that exceed 215 dB 
re 1 [mu]Pa @1 m, this cutoff

[[Page 66922]]

distance is substantially increased (i.e., doubled) from values derived 
from the literature. The use of multiple platforms and intense sound 
sources are factors that probably increase responsiveness in marine 
mammals overall (however, we note that helicopter dipping sonars were 
considered in the intense sound source group, despite lower source 
levels, because of data indicating that marine mammals are sometimes 
more responsive to the less predictable employment of this source). 
There are currently few behavioral observations under these 
circumstances; therefore, the Navy conservatively predicted significant 
behavioral responses that would rise to Level B harassment at farther 
ranges as shown in Table 17, versus less intense events.

  Table 17--Cutoff Distances for Moderate Source Level, Single Platform
   Training and Testing Events and for All Other Events With Multiple
Platforms or Sonar With Source Levels at or Exceeding 215 dB re 1 [mu]Pa
                                  @1 m
------------------------------------------------------------------------
                                           Moderate SlL/
                                              single      High SL/multi-
             Criteria group                  platform        platform
                                              cutoff          cutoff
                                           distance (km)   distance (km)
------------------------------------------------------------------------
Odontocetes.............................              10              20
Pinnipeds...............................               5              10
Mysticetes..............................              10              20
Beaked Whales...........................              25              50
------------------------------------------------------------------------
Note: dB re 1 [mu]Pa @1 m: Decibels referenced to 1 micropascal at 1
  meter; km: Kilometer; SL: Source level.

    The range to received sound levels in 6-dB steps from five 
representative sonar bins and the percentage of animals that may be 
taken by Level B harassment under each behavioral response function (or 
step function in the case of the harbor porpoise) are shown in Table 18 
through Table 22. Cells are shaded if the mean range value for the 
specified received level exceeds the distance cutoff range for a 
particular hearing group and therefore are not included in the 
estimated take. See Chapter 6, Section 6.4.2.1.1 (Methods for Analyzing 
Impacts from Sonars and Other Transducers) of the Navy's rulemaking/LOA 
application for further details on the derivation and use of the 
behavioral response functions, thresholds, and the cutoff distances to 
identify takes by Level B harassment, which were coordinated with NMFS. 
Table 18 illustrates the maximum likely percentage of exposed 
individuals taken at the indicated received level and associated range 
(in which marine mammals would be reasonably expected to experience a 
disruption in behavior patterns to a point where they are abandoned or 
significantly altered) for LFAS. As noted previously, NMFS carefully 
reviewed, and contributed to, the Navy's proposed level B behavioral 
harassment thresholds and cutoff distances for the species, and agrees 
that these methods represent the best available science at this time 
for determining impacts to marine mammals from sonar and other 
transducers.

[[Page 66923]]

[GRAPHIC] [TIFF OMITTED] TR27DE18.020

    Tables 19 through Table 21 identify the maximum likely percentage 
of exposed individuals taken at the indicated received level and 
associated range for MFAS.

[[Page 66924]]

[GRAPHIC] [TIFF OMITTED] TR27DE18.021


[[Page 66925]]


[GRAPHIC] [TIFF OMITTED] TR27DE18.022


[[Page 66926]]


[GRAPHIC] [TIFF OMITTED] TR27DE18.023


[[Page 66927]]


[GRAPHIC] [TIFF OMITTED] TR27DE18.024

    Table 22 identifies the maximum likely percentage of exposed 
individuals taken at the indicated received level and associated range 
for HFAS.

Explosives

    Phase III explosive criteria for Level B behavioral harassment 
thresholds for marine mammals is the hearing groups' TTS threshold 
minus 5 dB (see Table 23 below and Table 15 for the TTS thresholds for 
explosives) for events that contain multiple impulses from explosives 
underwater. This was the same approach as taken in Phase II for 
explosive analysis. See the Criteria and Thresholds for U.S. Navy 
Acoustic and Explosive Effects Analysis (Phase III) report (U.S. 
Department of the Navy, 2017c) for detailed information on how the 
criteria and thresholds were derived. NMFS continues to concur that 
this approach represents the best available science for determining 
impacts to marine mammals from explosives.

[[Page 66928]]



    Table 23--Phase III Level B Behavioral Harassment Thresholds for
                      Explosives for Marine Mammals
------------------------------------------------------------------------
                                        Functional hearing       SEL
               Medium                         group           (weighted)
------------------------------------------------------------------------
Underwater..........................  LF                             163
Underwater..........................  MF                             165
Underwater..........................  HF                             135
Underwater..........................  PW                             165
Underwater..........................  OW                             183
------------------------------------------------------------------------
Note: Weighted SEL thresholds in dB re 1 [mu]Pa\2\s underwater. PW--
  pinnipeds underwater, OW--otariids underwater.

Navy's Acoustic Effects Model

Sonar and Other Transducers and Explosives
    The Navy's Acoustic Effects Model calculates sound energy 
propagation from sonar and other transducers and explosives during 
naval activities and the sound received by animat dosimeters. Animat 
dosimeters are virtual representations of marine mammals distributed in 
the area around the modeled naval activity and each dosimeter records 
its individual sound ``dose.'' The model bases the distribution of 
animats over the HSTT Study Area on the density values in the Navy 
Marine Species Density Database and distributes animats in the water 
column proportional to the known time that species spend at varying 
depths.
    The model accounts for environmental variability of sound 
propagation in both distance and depth when computing the received 
sound level received by the animats. The model conducts a statistical 
analysis based on multiple model runs to compute the estimated effects 
on animals. The number of animats that exceed the thresholds for 
effects is tallied to provide an estimate of the number of marine 
mammals that could be affected.
    Assumptions in the Navy model intentionally err on the side of 
overestimation when there are unknowns. Naval activities are modeled as 
though they would occur regardless of proximity to marine mammals, 
meaning that no mitigation is considered (i.e., no power down or shut 
down modeled) and without any avoidance of the activity by the animal. 
The final step of the quantitative analysis of acoustic effects is to 
consider the implementation of mitigation and the possibility that 
marine mammals would avoid continued or repeated sound exposures. For 
more information on this process, see the discussion in the Take 
Requests subsection below. Many explosions from ordnance such as bombs 
and missiles actually occur upon impact with above-water targets. 
However, for this analysis, sources such as these were modeled as 
exploding underwater. This overestimates the amount of explosive and 
acoustic energy entering the water.
    The model estimates the impacts caused by individual training and 
testing exercises. During any individual modeled event, impacts to 
individual animats are considered over 24-hour periods. The animats do 
not represent actual animals, but rather they represent a distribution 
of animals based on density and abundance data, which allows for a 
statistical analysis of the number of instances that marine mammals may 
be exposed to sound levels resulting in an effect. Therefore, the model 
estimates the number of instances in which an effect threshold was 
exceeded over the course of a year, but does not estimate the number of 
individual marine mammals that may be impacted over a year (i.e., some 
marine mammals could be impacted several times, while others would not 
experience any impact). A detailed explanation of the Navy's Acoustic 
Effects Model is provided in the technical report Quantifying Acoustic 
Impacts on Marine Mammals and Sea Turtles: Methods and Analytical 
Approach for Phase III Training and Testing report (U.S. Department of 
the Navy, 2018).
Air Guns and Pile Driving
    The Navy's quantitative analysis estimates the sound and energy 
received by marine mammals distributed in the area around planned Navy 
activities involving air guns. See the technical report titled 
Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods 
and Analytical Approach for Phase III Training and Testing report (U.S. 
Department of the Navy, 2018) for additional details.
    Underwater noise effects from pile driving and vibratory pile 
extraction were modeled using actual measures of impact pile driving 
and vibratory removal during construction of an ELCAS (Illingworth and 
Rodkin, 2015, 2016). A conservative estimate of spreading loss of sound 
in shallow coastal waters (i.e., transmission loss = 16.5*Log10 
(radius)) was applied based on spreading loss observed in actual 
measurements. Inputs used in the model are provided in Chapter 1, 
Section 1.4.1.3 (Pile Driving) of the Navy's rulemaking/LOA 
application, including source levels; the number of strikes required to 
drive a pile and the duration of vibratory removal per pile; the number 
of piles driven or removed per day; and the number of days of pile 
driving and removal.

Range to Effects

    The following section provides range to effects for sonar and other 
active acoustic sources as well as explosives to specific acoustic 
thresholds determined using the Navy Acoustic Effects Model. Marine 
mammals exposed within these ranges for the shown duration are 
predicted to experience the associated effect. Range to effects is 
important information in not only predicting acoustic impacts, but also 
in verifying the accuracy of model results against real-world 
situations and determining adequate mitigation ranges to avoid higher 
level effects, especially physiological effects to marine mammals.
Sonar
    The range to received sound levels in 6-dB steps from five 
representative sonar bins and the percentage of the total number of 
animals that may exhibit a significant behavioral response (and 
therefore Level B harassment) under each behavioral response function 
(or step function in the case of the harbor porpoise) are shown in 
Table 17 through Table 21 above, respectively. See Chapter 6, Section 
6.4.2.1 (Methods for Analyzing Impacts from Sonars and Other 
Transducers) of the Navy's rulemaking/LOA application for additional 
details on the derivation and use of the behavioral response functions, 
thresholds, and the cutoff distances that are used to identify Level B 
behavioral harassment.
    The ranges to PTS for five representative sonar systems for an 
exposure of 30 seconds is shown in Table 24 relative to the marine 
mammal's functional hearing group. This period (30 seconds) was chosen 
based on examining the maximum amount of time a marine mammal would 
realistically be exposed to levels that could cause the onset of PTS 
based on platform (e.g., ship) speed and a nominal animal swim speed of 
approximately 1.5 m per second. The ranges provided in the table 
include the average range to PTS, as well as the range from the minimum 
to the maximum distance at which PTS is possible for each hearing 
group.

[[Page 66929]]



           Table 24--Range to Permanent Threshold Shift (Meters) for Five Representative Sonar Systems
----------------------------------------------------------------------------------------------------------------
                                           Approximate range in meters for PTS from 30 seconds exposure
    Functional hearing group     -------------------------------------------------------------------------------
                                   Sonar bin LF    Sonar bin MF1   Sonar bin MF4   Sonar bin MF5   Sonar bin HF4
----------------------------------------------------------------------------------------------------------------
Low-frequency Cetacean..........         0 (0-0)      65 (65-65)       14 (0-15)         0 (0-0)         0 (0-0)
Mid-frequency Cetacean..........         0 (0-0)      16 (16-16)         3 (3-3)         0 (0-0)         1 (0-2)
High-frequency Cetacean.........         0 (0-0)   181 (180-190)      30 (30-30)        9 (8-10)       30 (8-80)
Otariidae.......................         0 (0-0)         6 (6-6)         0 (0-0)         0 (0-0)         0 (0-0)
Phocidae........................         0 (0-0)      45 (45-45)      11 (11-11)         0 (0-0)         0 (0-0)
----------------------------------------------------------------------------------------------------------------
\1\ PTS ranges extend from the sonar or other active acoustic sound source to the indicated distance. The
  average range to PTS is provided as well as the range from the estimated minimum to the maximum range to PTS
  in parenthesis.

    The tables below illustrate the range to TTS for 1, 30, 60, and 120 
seconds from five representative sonar systems (see Table 25 through 
Table 29).

     Table 25--Ranges to Temporary Threshold Shift (Meters) for Sonar Bin LF5 Over a Representative Range of Environments Within the HSTT Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                          Approximate TTS ranges (meters) \1\
                                                             -------------------------------------------------------------------------------------------
                        Hearing group                                         Sonar bin LF5M (low frequency sources <180 dB source level)
                                                             -------------------------------------------------------------------------------------------
                                                                     1 second              30 seconds             60 seconds            120 seconds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-frequency Cetacean......................................                3 (0-4)                3 (0-4)                3 (0-4)                3 (0-4)
Mid-frequency Cetacean......................................                0 (0-0)                0 (0-0)                0 (0-0)                0 (0-0)
High-frequency Cetacean.....................................                0 (0-0)                0 (0-0)                0 (0-0)                0 (0-0)
Otariidae...................................................                0 (0-0)                0 (0-0)                0 (0-0)                0 (0-0)
Phocidae....................................................                0 (0-0)                0 (0-0)                0 (0-0)                0 (0-0)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Ranges to TTS represent the model predictions in different areas and seasons within the Study Area. The zone in which animals are expected to suffer
  TTS extend from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the
  maximum range to TTS in parentheses.


     Table 26--Ranges to Temporary Threshold Shift (Meters) for Sonar Bin MF1 Over a Representative Range of Environments within the HSTT Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                          Approximate TTS ranges (meters) \1\
                                                             -------------------------------------------------------------------------------------------
                        Hearing group                                             Sonar bin MF1 (e.g., SQS-53 ASW hull-mounted sonar)
                                                             -------------------------------------------------------------------------------------------
                                                                     1 second              30 seconds             60 seconds            120 seconds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-frequency Cetacean......................................        903 (850-1,025)        903 (850-1,025)    1,264 (1,025-2,275)    1,839 (1,275-3,025)
Mid-frequency Cetacean......................................          210 (210-210)          210 (210-210)          302 (300-310)          379 (370-390)
High-frequency Cetacean.....................................    3,043 (1,525-4,775)    3,043 (1,525-4,775)    4,739 (2,025-6,275)    5,614 (2,025-7,525)
Otariidae...................................................             65 (65-65)             65 (65-65)          106 (100-110)          137 (130-140)
Phocidae....................................................          669 (650-725)          669 (650-725)        970 (900-1,025)    1,075 (1,025-1,525)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Ranges to TTS represent the model predictions in different areas and seasons within the Study Area. The zone in which animals are expected to suffer
  TTS extend from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the
  maximum range to TTS in parentheses.


     Table 27--Ranges to Temporary Threshold Shift (Meters) for Sonar Bin MF4 Over a Representative Range of Environments Within the HSTT Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                          Approximate TTS ranges (meters) \1\
                                                             -------------------------------------------------------------------------------------------
                        Hearing group                                               Sonar bin MF4 (e.g., AQS-22 ASW dipping sonar)
                                                             -------------------------------------------------------------------------------------------
                                                                     1 second              30 seconds             60 seconds            120 seconds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-frequency Cetacean......................................              77 (0-85)          162 (150-180)          235 (220-290)          370 (310-600)
Mid-frequency Cetacean......................................             22 (22-22)             35 (35-35)             49 (45-50)             70 (70-70)
High-frequency Cetacean.....................................          240 (220-300)          492 (440-775)        668 (550-1,025)        983 (825-2,025)
Otariidae...................................................                8 (8-8)             15 (15-15)             19 (19-19)             25 (25-25)

[[Page 66930]]

 
Phocidae....................................................             65 (65-65)          110 (110-110)          156 (150-170)          269 (240-460)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Ranges to TTS represent the model predictions in different areas and seasons within the Study Area. The zone in which animals are expected to suffer
  TTS extend from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the
  maximum range to TTS in parentheses.


     Table 28--Ranges to Temporary Threshold Shift (Meters) for Sonar Bin MF5 Over a Representative Range of Environments Within the HSTT Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                          Approximate TTS ranges (meters) \1\
                                                             -------------------------------------------------------------------------------------------
                        Hearing group                                                  Sonar bin MF5 (e.g., SSQ-62 ASW Sonobuoy)
                                                             -------------------------------------------------------------------------------------------
                                                                     1 second              30 seconds             60 seconds            120 seconds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-frequency Cetacean......................................              10 (0-12)              10 (0-12)              14 (0-18)              21 (0-25)
Mid-frequency Cetacean......................................                6 (0-9)                6 (0-9)              12 (0-13)              17 (0-21)
High-frequency Cetacean.....................................          118 (100-170)          118 (100-170)          179 (150-480)          273 (210-700)
Otariidae...................................................                0 (0-0)                0 (0-0)                0 (0-0)                0 (0-0)
Phocidae....................................................               9 (8-10)               9 (8-10)             14 (14-16)             21 (21-25)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Ranges to TTS represent the model predictions in different areas and seasons within the Study Area. The zone in which animals are expected to suffer
  TTS extend from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the
  maximum range to TTS in parentheses.


     Table 29--Ranges to Temporary Threshold Shift (Meters) for Sonar Bin HF4 Over a Representative Range of Environments Within the HSTT Study Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                          Approximate TTS ranges (meters) \1\
                                                             -------------------------------------------------------------------------------------------
                        Hearing group                                               Sonar bin HF4 (e.g., SQS-20 mine hunting sonar)
                                                             -------------------------------------------------------------------------------------------
                                                                     1 second              30 seconds            >60 seconds            120 seconds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-frequency Cetacean......................................                1 (0-3)                2 (0-5)                4 (0-7)               6 (0-11)
Mid-frequency Cetacean......................................              10 (4-17)              17 (6-35)              24 (7-60)              34 (9-90)
High-frequency Cetacean.....................................           168 (25-550)           280 (55-775)         371 (80-1,275)        470 (100-1,525)
Otariidae...................................................                0 (0-0)                0 (0-0)                0 (0-0)                1 (0-1)
Phocidae....................................................                2 (0-5)                5 (2-8)               8 (3-13)              11 (4-22)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Ranges to TTS represent the model predictions in different areas and seasons within the Study Area. The zone in which animals are expected to suffer
  TTS extend from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the
  maximum range to TTS in parentheses.

Explosives
    The following section provides the range (distance) over which 
specific physiological or behavioral effects are expected to occur 
based on the explosive criteria (see Chapter 6, Section 6.5.2.1.1 of 
the Navy's rulemaking/LOA application and the Criteria and Thresholds 
for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III) 
report (U.S. Department of the Navy, 2017c) and the explosive 
propagation calculations from the Navy Acoustic Effects Model (see 
Chapter 6, Section 6.5.2.1.3, Navy Acoustic Effects Model of the Navy's 
rulemaking/LOA application). The range to effects are shown for a range 
of explosive bins, from E1 (up to 0.25 lb net explosive weight) to E12 
(up to 1,000 lb net explosive weight) (Tables 30 through 34). Ranges 
are determined by modeling the distance that noise from an explosion 
would need to propagate to reach exposure level thresholds specific to 
a hearing group that would cause behavioral response (to the degree of 
Level B behavioral harassment), TTS, PTS, and non-auditory injury. 
Ranges are provided for a representative source depth and cluster size 
for each bin. For events with multiple explosions, sound from 
successive explosions can be expected to accumulate and increase the 
range to the onset of an impact based on SEL thresholds. Ranges to non-
auditory injury and mortality are shown in Tables 35 and 36, 
respectively. Range to effects is important information in not only 
predicting impacts from explosives, but also in verifying the accuracy 
of model results against real-world situations and determining adequate 
mitigation ranges to avoid higher level effects, especially 
physiological effects to marine mammals. For additional information on 
how ranges to impacts from

[[Page 66931]]

explosions were estimated, see the technical report Quantifying 
Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and 
Analytical Approach for Phase III Training and Testing (U.S. Navy, 
2018).
    Table 30 shows the minimum, average, and maximum ranges to onset of 
auditory and likely behavioral effects that rise to the level of Level 
B harassment for high-frequency cetaceans based on the developed 
thresholds.

               Table 30--SEL-Based Ranges (Meters) to Onset PTS, Onset TTS, and Level B Behavioral Harassment for High-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                              Range to effects for explosives: High frequency cetacean \1\
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Source      Cluster
                       Bin                         depth (m)       size                PTS                       TTS                   Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E1..............................................          0.1            1             353 (130-825)         1,234 (290-3,025)         2,141 (340-4,775)
                                                                        25         1,188 (280-3,025)         3,752 (490-8,525)        5,196 (675-12,275)
E2..............................................          0.1            1           425 (140-1,275)         1,456 (300-3,525)         2,563 (390-5,275)
                                                                        10           988 (280-2,275)         3,335 (480-7,025)        4,693 (650-10,275)
E3..............................................          0.1            1           654 (220-1,525)         2,294 (350-4,775)         3,483 (490-7,775)
                                                                        12         1,581 (300-3,525)        4,573 (650-10,275)        6,188 (725-14,775)
                                                        18.25            1           747 (550-1,525)         3,103 (950-6,025)       5,641 (1,000-9,275)
                                                                        12         1,809 (875-4,025)      7,807 (1,025-12,775)     10,798 (1,025-17,775)
E4..............................................            3            2       2,020 (1,025-3,275)       3,075 (1,025-6,775)       3,339 (1,025-9,775)
                                                        15.25            2           970 (600-1,525)       4,457 (1,025-8,525)      6,087 (1,275-12,025)
                                                         19.8            2       1,023 (1,000-1,025)       4,649 (2,275-8,525)      6,546 (3,025-11,025)
                                                          198            2           959 (875-1,525)       4,386 (3,025-7,525)       5,522 (3,025-9,275)
E5..............................................          0.1           25         2,892 (440-6,275)        6,633 (725-16,025)        8,925 (800-22,775)
                                                        15.25           25       4,448 (1,025-7,775)     10,504 (1,525-18,275)     13,605 (1,775-24,775)
E6..............................................          0.1            1         1,017 (280-2,525)         3,550 (490-7,775)        4,908 (675-12,275)
                                                            3            1       2,275 (2,025-2,525)       6,025 (4,525-7,275)       7,838 (6,275-9,775)
                                                        15.25            1         1,238 (625-2,775)      5,613 (1,025-10,525)      7,954 (1,275-14,275)
E7..............................................            3            1       3,150 (2,525-3,525)       7,171 (5,525-8,775)      8,734 (7,275-10,525)
                                                        18.25            1         2,082 (925-3,525)      6,170 (1,275-10,525)      8,464 (1,525-16,525)
E8..............................................          0.1            1         1,646 (775-2,525)       4,322 (1,525-9,775)      5,710 (1,525-14,275)
                                                        45.75            1       1,908 (1,025-4,775)      5,564 (1,525-12,525)      7,197 (1,525-18,775)
E9..............................................          0.1            1         2,105 (850-4,025)      4,901 (1,525-12,525)      6,700 (1,525-16,775)
E10.............................................          0.1            1         2,629 (875-5,275)      5,905 (1,525-13,775)      7,996 (1,525-20,025)
E11.............................................         18.5            1       3,034 (1,025-6,025)      7,636 (1,525-16,525)      9,772 (1,775-21,525)
                                                        45.75            1       2,925 (1,525-6,025)      7,152 (2,275-18,525)      9,011 (2,525-24,525)
E12.............................................          0.1            1         2,868 (975-5,525)      6,097 (2,275-14,775)      8,355 (4,275-21,275)
                                                                         3       3,762 (1,525-8,275)      7,873 (3,775-20,525)     10,838 (4,275-26,525)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses. Values
  depict the range produced by SEL hearing threshold criteria levels.
E13 not modeled due to surf zone use and lack of marine mammal receptors at site-specific location.

    Table 31 shows the minimum, average, and maximum ranges to onset of 
auditory and likely behavioral effects that rise to the level of Level 
B harassment for mid-frequency cetaceans based on the developed 
thresholds.

               Table 31--SEL-Based Ranges (Meters) to Onset PTS, Onset TTS, and Level B Behavioral Harassment for Mid-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                               Range to effects for explosives: Mid-frequency cetacean \1\
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Source      Cluster
                       Bin                         depth (m)       size                PTS                       TTS                   Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E1..............................................          0.1            1                25 (25-25)              118 (80-210)             178 (100-320)
                                                                        25              107 (75-170)           476 (150-1,275)           676 (240-1,525)
E2..............................................          0.1            1                30 (30-35)              145 (95-240)             218 (110-400)
                                                                        10               88 (65-130)             392 (140-825)           567 (190-1,275)
E3..............................................          0.1            1                50 (45-65)             233 (110-430)             345 (130-600)
                                                                        12              153 (90-250)           642 (220-1,525)           897 (270-2,025)
                                                        18.25            1                38 (35-40)             217 (190-900)             331 (290-850)
                                                                        12             131 (120-250)           754 (550-1,525)         1,055 (600-2,525)
E4..............................................            3            2             139 (110-160)         1,069 (525-1,525)         1,450 (875-1,775)
                                                        15.25            2                71 (70-75)             461 (400-725)             613 (470-750)
                                                         19.8            2                69 (65-70)             353 (350-360)             621 (600-650)
                                                          198            2                 49 (0-55)             275 (270-280)             434 (430-440)
E5..............................................          0.1           25             318 (130-625)         1,138 (280-3,025)         1,556 (310-3,775)
                                                        15.25           25             312 (290-725)         1,321 (675-2,525)         1,980 (850-4,275)
E6..............................................          0.1            1               98 (70-170)             428 (150-800)           615 (210-1,525)
                                                            3            1             159 (150-160)             754 (650-850)       1,025 (1,025-1,025)
                                                        15.25            1               88 (75-180)             526 (450-875)           719 (500-1,025)

[[Page 66932]]

 
E7..............................................            3            1             240 (230-260)       1,025 (1,025-1,025)       1,900 (1,775-2,275)
                                                        18.25            1             166 (120-310)           853 (500-1,525)         1,154 (550-1,775)
E8..............................................          0.1            1             160 (150-170)             676 (500-725)           942 (600-1,025)
                                                        45.75            1             128 (120-170)           704 (575-2,025)         1,040 (750-2,525)
E9..............................................          0.1            1             215 (200-220)             861 (575-950)         1,147 (650-1,525)
E10.............................................          0.1            1             275 (250-480)         1,015 (525-2,275)         1,424 (675-3,275)
E11.............................................         18.5            1             335 (260-500)         1,153 (650-1,775)         1,692 (775-3,275)
                                                        45.75            1             272 (230-825)         1,179 (825-3,025)       1,784 (1,000-4,275)
E12.............................................          0.1            1             334 (310-350)         1,151 (700-1,275)         1,541 (800-3,525)
                                                          0.1            3             520 (450-550)         1,664 (800-3,525)         2,195 (925-4,775)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses. Values
  depict the range produced by SEL hearing threshold criteria levels.
E13 not modeled due to surf zone use and lack of marine mammal receptors at site-specific location.

    Table 32 shows the minimum, average, and maximum ranges to onset of 
auditory and likely behavioral effects that rise to the level of Level 
B harassment for low-frequency cetaceans based on the developed 
thresholds.

               Table 32--SEL-Based Ranges (Meters) to Onset PTS, Onset TTS, and Level B Behavioral Harassment for Low-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Range to effects for explosives: Low frequency cetacean 1
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Source      Cluster
                       Bin                         depth (m)       size                PTS                       TTS                   Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E1..............................................          0.1            1                51 (40-70)             227 (100-320)              124 (70-160)
                                                                        25              205 (95-270)           772 (270-1,275)             476 (190-725)
E2..............................................          0.1            1                65 (45-95)             287 (120-400)              159 (80-210)
                                                                        10              176 (85-240)           696 (240-1,275)             419 (160-625)
E3..............................................          0.1            1              109 (65-150)           503 (190-1,000)             284 (120-430)
                                                                        12             338 (130-525)         1,122 (320-7,775)           761 (240-6,025)
                                                        18.25            1             205 (170-340)           996 (410-2,275)           539 (330-1,275)
                                                                        12           651 (340-1,275)         3,503 (600-8,275)         1,529 (470-3,275)
E4..............................................            3            2           493 (440-1,000)       2,611 (1,025-4,025)         1,865 (950-2,775)
                                                        15.25            2             583 (350-850)       3,115 (1,275-5,775)       1,554 (1,000-2,775)
                                                         19.8            2             378 (370-380)       1,568 (1,275-1,775)             926 (825-950)
                                                          198            2             299 (290-300)       2,661 (1,275-3,775)             934 (900-950)
E5..............................................          0.1           25           740 (220-6,025)        2,731 (460-22,275)        1,414 (350-14,275)
                                                        15.25           25       1,978 (1,025-5,275)      8,188 (3,025-19,775)      4,727 (1,775-11,525)
E6..............................................          0.1            1             250 (100-420)           963 (260-7,275)           617 (200-1,275)
                                                            3            1             711 (525-825)       3,698 (1,525-4,275)       2,049 (1,025-2,525)
                                                        15.25            1           718 (390-2,025)       3,248 (1,275-8,525)         1,806 (950-4,525)
E7..............................................            3            1         1,121 (850-1,275)       5,293 (2,025-6,025)       3,305 (1,275-4,025)
                                                        18.25            1       1,889 (1,025-2,775)      6,157 (2,775-11,275)       4,103 (2,275-7,275)
E8..............................................          0.1            1             460 (170-950)         1,146 (380-7,025)           873 (280-3,025)
                                                        45.75            1         1,049 (550-2,775)      4,100 (1,025-14,275)         2,333 (800-7,025)
E9..............................................          0.1            1           616 (200-1,275)        1,560 (450-12,025)         1,014 (330-5,025)
E10.............................................          0.1            1           787 (210-2,525)        2,608 (440-18,275)         1,330 (330-9,025)
E11.............................................         18.5            1       4,315 (2,025-8,025)     10,667 (4,775-26,775)      7,926 (3,275-21,025)
                                                        45.75            1         1,969 (775-5,025)      9,221 (2,525-29,025)      4,594 (1,275-16,025)
E12.............................................          0.1            1           815 (250-3,025)        2,676 (775-18,025)         1,383 (410-8,525)
                                                          0.1            3         1,040 (330-6,025)      4,657 (1,275-31,275)        2,377 (700-16,275)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances, which are in parentheses. Values
  depict the range produced by SEL hearing threshold criteria levels.
E13 not modeled due to surf zone use and lack of marine mammal receptors at site-specific location.

    Table 33 shows the minimum, average, and maximum ranges to onset of 
auditory and likely behavioral effects that rise to the level of Level 
B harassment for phocids based on the developed thresholds.

[[Page 66933]]



                       Table 33--SEL-Based Ranges (Meters) to Onset PTS, Onset TTS, and Level B Behavioral Harassment for Phocids
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Range to effects for explosives: Phocids 1
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Source      Cluster
                       Bin                         depth (m)       size                PTS                       TTS                   Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E1..............................................          0.1            1                45 (40-65)             210 (100-290)             312 (130-430)
                                                                        25              190 (95-260)           798 (280-1,275)         1,050 (360-2,275)
E2..............................................          0.1            1                58 (45-75)             258 (110-360)             383 (150-550)
                                                                        10              157 (85-240)           672 (240-1,275)           934 (310-1,525)
E3..............................................          0.1            1               96 (60-120)             419 (160-625)             607 (220-900)
                                                                        12             277 (120-390)         1,040 (370-2,025)         1,509 (525-6,275)
                                                        18.25            1             118 (110-130)           621 (500-1,275)           948 (700-2,025)
                                                                        12             406 (330-875)       1,756 (1,025-4,775)       3,302 (1,025-6,275)
E4..............................................            3            2             405 (300-430)       1,761 (1,025-2,775)       2,179 (1,025-3,275)
                                                        15.25            2             265 (220-430)         1,225 (975-1,775)       1,870 (1,025-3,275)
                                                         19.8            2             220 (220-220)           991 (950-1,025)       1,417 (1,275-1,525)
                                                          198            2             150 (150-150)           973 (925-1,025)       2,636 (2,025-3,525)
E5..............................................          0.1           25             569 (200-850)         2,104 (725-9,275)        2,895 (825-11,025)
                                                        15.25           25           920 (825-1,525)      5,250 (2,025-10,275)      7,336 (2,275-16,025)
E6..............................................          0.1            1              182 (90-250)           767 (270-1,275)         1,011 (370-1,775)
                                                            3            1             392 (340-440)       1,567 (1,275-1,775)       2,192 (2,025-2,275)
                                                        15.25            1             288 (250-600)       1,302 (1,025-3,275)       2,169 (1,275-5,775)
E7..............................................            3            1             538 (450-625)       2,109 (1,775-2,275)       2,859 (2,775-3,275)
                                                        18.25            1             530 (460-750)       2,617 (1,025-4,525)       3,692 (1,525-5,275)
E8..............................................          0.1            1             311 (290-330)         1,154 (625-1,275)         1,548 (725-2,275)
                                                        45.75            1             488 (380-975)       2,273 (1,275-5,275)       3,181 (1,525-8,025)
E9..............................................          0.1            1             416 (350-470)         1,443 (675-2,025)         1,911 (800-3,525)
E10.............................................          0.1            1             507 (340-675)         1,734 (725-3,525)         2,412 (800-5,025)
E11.............................................         18.5            1         1,029 (775-1,275)       5,044 (2,025-8,775)      6,603 (2,525-14,525)
                                                        45.75            1           881 (700-2,275)       3,726 (2,025-8,775)      5,082 (2,025-13,775)
E12.............................................          0.1            1             631 (450-750)         1,927 (800-4,025)         2,514 (925-5,525)
                                                          0.1            3           971 (550-1,025)       2,668 (1,025-6,275)       3,541 (1,775-9,775)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses. Values
  depict the range produced by SEL hearing threshold criteria levels.
E13 not modeled due to surf zone use and lack of marine mammal receptors at site-specific location.

    Table 34 shows the minimum, average, and maximum ranges to onset of 
auditory and likely behavioral effects that rise to the level of Level 
B harassment for ottariids based on the developed thresholds.

                       Table 34--SEL-Based Ranges (Meters) to Onset PTS, Onset TTS, and Level B Behavioral Harassment for Otariids
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Range to effects for explosives: Otariids 1
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Source      Cluster
                       Bin                         depth (m)       size                PTS                       TTS                   Behavioral
--------------------------------------------------------------------------------------------------------------------------------------------------------
E1..............................................          0.1            1                   7 (7-7)                34 (30-40)                56 (45-70)
                                                                        25                30 (25-35)              136 (80-180)             225 (100-320)
E2..............................................          0.1            1                   9 (9-9)                41 (35-55)                70 (50-95)
                                                                        10                25 (25-30)              115 (70-150)              189 (95-250)
E3..............................................          0.1            1                16 (15-19)                70 (50-95)              115 (70-150)
                                                                        12                45 (35-65)             206 (100-290)             333 (130-450)
                                                        18.25            1                15 (15-15)               95 (90-100)             168 (150-310)
                                                                        12                55 (50-60)             333 (280-750)           544 (440-1,025)
E4..............................................            3            2                64 (40-85)             325 (240-340)             466 (370-490)
                                                        15.25            2                30 (30-35)             205 (170-300)             376 (310-575)
                                                         19.8            2                25 (25-25)             170 (170-170)             290 (290-290)
                                                          198            2                 17 (0-25)             117 (110-120)             210 (210-210)
E5..............................................          0.1           25               98 (60-120)             418 (160-575)           626 (240-1,000)
                                                        15.25           25             151 (140-260)           750 (650-1,025)         1,156 (975-2,025)
E6..............................................          0.1            1                30 (25-35)              134 (75-180)             220 (100-320)
                                                            3            1                53 (50-55)             314 (280-390)             459 (420-525)
                                                        15.25            1                36 (35-40)             219 (200-380)             387 (340-625)
E7..............................................            3            1               93 (90-100)             433 (380-500)             642 (550-800)
                                                        18.25            1                73 (70-75)             437 (360-525)             697 (600-850)
E8..............................................          0.1            1                50 (50-50)             235 (220-250)             385 (330-450)
                                                        45.75            1                55 (55-60)             412 (310-775)           701 (500-1,525)
E9..............................................          0.1            1                68 (65-70)             316 (280-360)             494 (390-625)

[[Page 66934]]

 
E10.............................................          0.1            1                86 (80-95)             385 (240-460)             582 (390-800)
E11.............................................         18.5            1             158 (150-200)             862 (750-975)       1,431 (1,025-2,025)
                                                        45.75            1             117 (110-130)           756 (575-1,525)         1,287 (950-2,775)
E12.............................................          0.1            1             104 (100-110)             473 (370-575)           709 (480-1,025)
                                                          0.1            3             172 (170-180)           694 (480-1,025)           924 (575-1,275)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses. Values
  depict the range produced by SEL hearing threshold criteria levels.
E13 not modeled due to surf zone use and lack of marine mammal receptors at site-specific location.

    Table 35 shows the minimum, average, and maximum ranges due to 
varying propagation conditions to non-auditory injury as a function of 
animal mass and explosive bin (i.e., net explosive weight). Ranges to 
gastrointestinal tract injury typically exceed ranges to slight lung 
injury; therefore, the maximum range to effect is not mass-dependent. 
Animals within these water volumes would be expected to receive minor 
injuries at the outer ranges, increasing to more substantial injuries, 
and finally mortality as an animal approaches the detonation point.

   Table 35--Ranges \1\ to 50 Percent Non-Auditory Injury Risk for All
                      Marine Mammal Hearing Groups
------------------------------------------------------------------------
                      Bin                          Range (m) (min-max)
------------------------------------------------------------------------
E1............................................                12 (11-13)
E2............................................                15 (15-20)
E3............................................                25 (25-30)
E4............................................                 32 (0-75)
E5............................................               40 (35-140)
E6............................................               52 (40-120)
E7............................................             145 (100-500)
E8............................................              117 (75-400)
E9............................................              120 (90-290)
E10...........................................             174 (100-480)
E11...........................................           443 (350-1,775)
E12...........................................             232 (110-775)
------------------------------------------------------------------------
Note: \1\ Average distance (m) to mortality is depicted above the
  minimum and maximum distances which are in parentheses.
E13 not modeled due to surf zone use and lack of marine mammal receptors
  at site-specific location. Differences between bins E11 and E12 due to
  different ordnance types and differences in model parameters.

    Ranges to mortality, based on animal mass, are show in Table 36 
below.

                   Table 36--Ranges \1\ to 50 Percent Mortality Risk for All Marine Mammal Hearing Groups as a Function of Animal Mass
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                       Animal mass intervals (kg) \1\
                        Bin                        -----------------------------------------------------------------------------------------------------
                                                           10              250             1,000            5,000            25,000          >72,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
E1................................................          3 (2-3)          0 (0-3)          0 (0-0)          0 (0-0)          0 (0-0)          0 (0-0)
E2................................................          4 (3-5)          1 (0-4)          0 (0-0)          0 (0-0)          0 (0-0)          0 (0-0)
E3................................................         8 (6-10)          4 (2-8)          1 (0-2)          0 (0-0)          0 (0-0)          0 (0-0)
E4................................................        15 (0-35)         9 (0-30)          4 (0-8)          2 (0-6)          0 (0-3)          0 (0-2)
E5................................................       13 (11-45)         7 (4-35)         3 (3-12)          2 (0-8)          0 (0-2)          0 (0-2)
E6................................................       18 (14-55)        10 (5-45)         5 (3-15)         3 (2-10)          0 (0-3)          0 (0-2)
E7................................................      67 (55-180)      35 (18-140)       16 (12-30)        10 (8-20)          5 (4-9)          4 (3-7)
E8................................................      50 (24-110)        27 (9-55)        13 (0-20)         9 (4-13)          4 (0-6)          3 (0-5)
E9................................................       32 (30-35)       20 (13-30)        10 (8-12)          7 (6-9)          4 (3-4)          3 (2-3)
E10...............................................      56 (40-190)      25 (16-130)       13 (11-16)         9 (7-11)          5 (4-5)          4 (3-4)
E11...............................................    211 (180-500)     109 (60-330)      47 (40-100)       30 (25-65)        15 (0-25)       13 (11-22)
E12...............................................      94 (50-300)      35 (20-230)       16 (13-19)        11 (9-13)          6 (5-8)          5 (4-8)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: \1\ Average distance (m) to mortality is depicted above the minimum and maximum distances which are in parentheses.
E13 not modeled due to surf zone use and lack of marine mammal receptors at site-specific location.
Differences between bins E11 and E12 due to different ordnance types and differences in model parameters (see Table 6-42 for details).


[[Page 66935]]

Air Guns
    Table 37 and Table 38 present the approximate ranges in meters to 
PTS, TTS, and likely behavioral responses that rise to the level of a 
take for air guns for 1 and 10 pulses, respectively. Ranges are 
specific to the HSTT Study Area and also to each marine mammal hearing 
group, dependent upon their criteria and the specific locations where 
animals from the hearing groups and the air gun activities could 
overlap. Small air guns (12-60 in\3\) would be used during testing 
activities in the offshore areas of the Southern California Range 
Complex and in the Hawaii Range Complex. Generated impulses would have 
short durations, typically a few hundred milliseconds, with dominant 
frequencies below 1 kHz. The SPL and SPL peak (at a distance 1 m from 
the air gun) would be approximately 215 dB re 1 [micro]Pa and 227 dB re 
1 [micro]Pa, respectively, if operated at the full capacity of 60 
in\3\. The size of the air gun chamber can be adjusted, which would 
result in lower SPLs and SEL per shot. Single, small air guns lack the 
peak pressures that could cause non-auditory injury (see Finneran et 
al., 2015); therefore, potential impacts could include PTS, TTS, and/or 
Level B behavioral harassment.

                          Table 37--Range to Effects (Meters) From Air Guns for 1 Pulse
----------------------------------------------------------------------------------------------------------------
                                Range to effects for air guns \1\ for 1 pulse (m)
-----------------------------------------------------------------------------------------------------------------
        Hearing group             PTS (SEL)    PTS (Peak SPL)     TTS (SEL)    TTS (Peak SPL)    Behavioral \2\
----------------------------------------------------------------------------------------------------------------
High-Frequency Cetacean......         0 (0-0)      18 (15-25)         1 (0-2)      33 (25-80)    702 (290-1,525)
Low-Frequency Cetacean.......         3 (3-4)         2 (2-3)      27 (23-35)         5 (4-7)    651 (200-1,525)
Mid-Frequency Cetacean.......         0 (0-0)         0 (0-0)         0 (0-0)         0 (0-0)    689 (290-1,525)
Otariidae....................         0 (0-0)         0 (0-0)         0 (0-0)         0 (0-0)    590 (290-1,525)
Phocidae.....................         0 (0-0)         2 (2-3)         0 (0-0)         5 (4-8)    668 (290-1,525)
----------------------------------------------------------------------------------------------------------------
\1\ Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum
  distances which are in parentheses. PTS and TTS values depict the range produced by SEL and Peak SPL (as
  noted) hearing threshold criteria levels.
\2\ Behavioral values depict the ranges produced by RMS hearing threshold criteria levels.


                         Table 38--Range to Effects (Meters) From Air Guns for 10 Pulses
----------------------------------------------------------------------------------------------------------------
                               Range to Effects for Air Guns \1\ for 10 pulses (m)
-----------------------------------------------------------------------------------------------------------------
        Hearing group             PTS (SEL)    PTS (Peak SPL)     TTS (SEL)    TTS (Peak SPL)    Behavioral \2\
----------------------------------------------------------------------------------------------------------------
High-Frequency Cetacean......         0 (0-0)      18 (15-25)         3 (0-9)      33 (25-80)    702 (290-1,525)
Low-Frequency Cetacean.......      15 (12-20)         2 (2-3)     86 (70-140)         5 (4-7)    651 (200-1,525)
Mid-Frequency Cetacean.......         0 (0-0)         0 (0-0)         0 (0-0)         0 (0-0)    689 (290-1,525)
Otariidae....................         0 (0-0)         0 (0-0)         0 (0-0)         0 (0-0)    590 (290-1,525)
Phocidae.....................         0 (0-0)         2 (2-3)         4 (3-5)         5 (4-8)    668 (290-1,525)
----------------------------------------------------------------------------------------------------------------
\1\ Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum
  distances which are in parentheses. PTS and TTS values depict the range produced by SEL and Peak SPL (as
  noted) hearing threshold criteria levels.
\2\ Behavioral values depict the ranges produced by RMS hearing threshold criteria levels.

Pile Driving
    Table 39 and Table 40 present the approximate ranges in meters to 
PTS, TTS, and/or Level B behavioral harassment that rise to the level 
of a take for impact pile driving and vibratory pile removal, 
respectively. Non-auditory injury is not predicted for pile driving 
activities.

                      Table 39--Average Ranges to Effects (Meters) From Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
                          Hearing group                               PTS (m)         TTS (m)     Behavioral (m)
----------------------------------------------------------------------------------------------------------------
Low-Frequency Cetaceans.........................................              65             529             870
Mid-Frequency Cetaceans.........................................               2              16             870
High-Frequency Cetaceans........................................              65             529             870
Phocidae........................................................              19             151             870
Otariidae.......................................................               2              12             870
----------------------------------------------------------------------------------------------------------------
Note: PTS: permanent threshold shift; TTS: temporary threshold shift.


                   Table 40--Average Ranges to Effect (Meters) From Vibratory Pile Extraction
----------------------------------------------------------------------------------------------------------------
                          Hearing group                               PTS (m)         TTS (m)     Behavioral (m)
----------------------------------------------------------------------------------------------------------------
Low-Frequency Cetaceans.........................................               0               3             376
Mid-Frequency Cetaceans.........................................               0               4             376
High-Frequency Cetaceans........................................               7             116             376
Phocidae........................................................               0               2             376
Otariidae.......................................................               0               0             376
----------------------------------------------------------------------------------------------------------------
Note: PTS: permanent threshold shift; TTS: temporary threshold shift.


[[Page 66936]]

Marine Mammal Density

    A quantitative analysis of impacts on a species or stock requires 
data on their abundance and distribution that may be affected by 
anthropogenic activities in the potentially impacted area. The most 
appropriate metric for this type of analysis is density, which is the 
number of animals present per unit area. Marine species density 
estimation requires a significant amount of effort to both collect and 
analyze data to produce a reasonable estimate. Unlike surveys for 
terrestrial wildlife, many marine species spend much of their time 
submerged, and are not easily observed. In order to collect enough 
sighting data to make reasonable density estimates, multiple 
observations are required, often in areas that are not easily 
accessible (e.g., far offshore). Ideally, marine mammal species 
sighting data would be collected for the specific area and time period 
(e.g., season) of interest and density estimates derived accordingly. 
However, in many places, poor weather conditions and high sea states 
prohibit the completion of comprehensive visual surveys.
    For most cetacean species, abundance is estimated using line-
transect surveys or mark-recapture studies (e.g., Barlow, 2010; Barlow 
and Forney, 2007; Calambokidis et al., 2008). The result provides one 
single density estimate value for each species across broad geographic 
areas. This is the general approach applied in estimating cetacean 
abundance in the NMFS' SARs. Although the single value provides a good 
average estimate of abundance (total number of individuals) for a 
specified area, it does not provide information on the species 
distribution or concentrations within that area, and it does not 
estimate density for other timeframes or seasons that were not 
surveyed. More recently, spatial habitat modeling developed by NMFS' 
Southwest Fisheries Science Center has been used to estimate cetacean 
densities (Barlow et al., 2009; Becker et al., 2010, 2012a, b, c, 2014, 
2016; Ferguson et al., 2006a; Forney et al., 2012, 2015; Redfern et 
al., 2006). These models estimate cetacean density as a continuous 
function of habitat variables (e.g., sea surface temperature, seafloor 
depth, etc.) and thus allow predictions of cetacean densities on finer 
spatial scales than traditional line-transect or mark recapture 
analyses and for areas that have not been surveyed. Within the 
geographic area that was modeled, densities can be predicted wherever 
these habitat variables can be measured or estimated.
    To characterize the marine species density for large areas such as 
the HSTT Study Area, the Navy compiled data from several sources. The 
Navy developed a protocol to select the best available data sources 
based on species, area, and time (season). The resulting Geographic 
Information System database, called the Navy Marine Species Density 
Database includes seasonal density values for every marine mammal 
species present within the HSTT Study Area. This database is described 
in the technical report titled U.S. Navy Marine Species Density 
Database Phase III for the Hawaii-Southern California Training and 
Testing Study Area (U.S. Department of the Navy, 2017e), hereafter 
referred to as the Density Technical Report.
    A variety of density data and density models are needed in order to 
develop a density database that encompasses the entirety of the HSTT 
Study Area. Because this data is collected using different methods with 
varying amounts of accuracy and uncertainty, the Navy has developed a 
hierarchy to ensure the most accurate data is used when available. The 
Density Technical Report describes these models in detail and provides 
detailed explanations of the models applied to each species density 
estimate. The below list describes models in order of preference.
    1. Spatial density models are preferred and used when available 
because they provide an estimate with the least amount of uncertainty 
by deriving estimates for divided segments of the sampling area. These 
models (see Becker et al., 2016; Forney et al., 2015) predict spatial 
variability of animal presence as a function of habitat variables 
(e.g., sea surface temperature, seafloor depth, etc.). This model is 
developed for areas, species, and, when available, specific timeframes 
(months or seasons) with sufficient survey data; therefore, this model 
cannot be used for species with low numbers of sightings.
    2. Stratified design-based density estimates use line-transect 
survey data with the sampling area divided (stratified) into sub-
regions, and a density is predicted for each sub-region (see Barlow, 
2016; Becker et al., 2016; Bradford et al., 2017; Campbell et al., 
2014; Jefferson et al., 2014). While geographically stratified density 
estimates provide a better indication of a species' distribution within 
the study area, the uncertainty is typically high because each sub-
region estimate is based on a smaller stratified segment of the overall 
survey effort.
    3. Design-based density estimations use line-transect survey data 
from land and aerial surveys designed to cover a specific geographic 
area (see Carretta et al., 2015). These estimates use the same survey 
data as stratified design-based estimates, but are not segmented into 
sub-regions and instead provide one estimate for a large surveyed area. 
Although relative environmental suitability (RES) models provide 
estimates for areas of the oceans that have not been surveyed using 
information on species occurrence and inferred habitat associations and 
have been used in past density databases, these models were not used in 
the current quantitative analysis. In the HSTT analysis, due to the 
availability of other density methods along the hierarchy the use of 
RES model was not necessary.
    When interpreting the results of the quantitative analysis, as 
described in the Density Technical Report, ``it is important to 
consider that even the best estimate of marine species density is 
really a model representation of the values of concentration where 
these animals might occur. Each model is limited to the variables and 
assumptions considered by the original data source provider. No 
mathematical model representation of any biological population is 
perfect, and with regards to marine mammal biodiversity, any single 
model method will not completely explain the actual distribution and 
abundance of marine mammal species. It is expected that there would be 
anomalies in the results that need to be evaluated, with independent 
information for each case, to support if we might accept or reject a 
model or portions of the model (U.S. Department of the Navy, 2017a).''
    The Navy's estimate of abundance (based on the density estimates 
used) in the HSTT Study Area may differ from population abundances 
estimated in the NMFS' SARS in some cases for a variety of reasons. 
Models may predict different population abundances for many reasons, 
including being based on different data sets, different areas, or 
different time periods. The SARs are often based on single years of 
NMFS surveys, whereas the models used by the Navy generally include 
multiple years of survey data from NMFS, the Navy, and other sources. 
To present a single, best estimate, the SARs often use a single season 
survey where they have the best spatial coverage (generally Summer). 
Navy models often use predictions for multiple seasons, where 
appropriate for the species, even when survey coverage in non-Summer 
seasons is limited, to characterize impacts over multiple seasons as 
Navy activities may occur in any season. Predictions may be made for 
different spatial extents. For

[[Page 66937]]

example, the SAR encompasses the U.S. EEZ, while the HSTT Study area 
overlaps only part of the U.S. EEZ (specifically, the Pacific SAR 
overlaps only 35 percent of the Hawaii part of the HSTT Study Area and 
only about 14 percent of SOCAL), but alternately extends out 
significantly beyond it to the West. Many different, but equally valid, 
habitat and density modeling techniques exist and these can also be the 
cause of differences in population predictions. Differences in 
population estimates may be caused by a combination of these factors. 
Even similar estimates should be interpreted with caution and 
differences in models fully understood before drawing conclusions.
    The global population structure of humpbacks, with 14 DPSs all 
associated with multiple feeding areas at which individuals from 
multiple DPSs convene, is another reason that SAR abundance estimates 
can differ from other estimates and be somewhat confusing--the same 
individuals are addressed in multiple SARs. For some species, the stock 
assessment for a given species may exceed the Navy's density prediction 
because those species' home range extends beyond the Study Area 
boundaries. For other species, the stock assessment abundance may be 
much less than the number of animals in the Navy's modeling because the 
HSTT Study Area extends well beyond the U.S. waters covered by the SAR 
abundance estimate. The primary source of density estimates are 
geographically specific survey data and either peer-reviewed line-
transect estimates or habitat-based density models that have been 
extensively validated to provide the most accurate estimates possible.
    These factors and others described in the Density Technical Report 
should be considered when examining the estimated impact numbers in 
comparison to current population abundance information for any given 
species or stock. For a detailed description of the density and 
assumptions made for each species, see the Density Technical Report.
    NMFS coordinated with the Navy in the development of its take 
estimates and concurs that the Navy's approach for density 
appropriately utilizes the best available science. Later, in the 
Analysis and Negligible Impact Determination section, we assess how the 
estimated take numbers compare to stock abundance in order to better 
understand the potential number of individuals impacted, and the 
rationale for which abundance estimate is used is included there.

Take Requests

    The HSTT FEIS/OEIS considered all training and testing activities 
proposed to occur in the HSTT Study Area that have the potential to 
result in the MMPA defined take of marine mammals. The Navy determined 
that the three stressors below could result in the incidental taking of 
marine mammals. NMFS has reviewed the Navy's data and analysis and 
determined that it is complete and accurate and agrees that the 
following stressors have the potential to result in takes of marine 
mammals from the Navy's planned activities.
    <bullet> Acoustics (sonar and other transducers; air guns; pile 
driving/extraction).
    <bullet> Explosives (explosive shock wave and sound (assumed to 
encompass the risk due to fragmentation)).
    <bullet> Physical Disturbance and Strike (vessel strike).
    NMFS reviewed, and agrees with, the Navy's conclusion that acoustic 
and explosive sources have the potential to result in incidental takes 
of marine mammals by harassment, serious injury, or mortality. NMFS 
carefully reviewed the Navy's analysis and conducted its own analysis 
of vessel strikes, determining that the likelihood of any particular 
species of large whale being struck is quite low. Nonetheless, NMFS 
agrees that vessel strikes have the potential to result in incidental 
take from serious injury or mortality for certain species of large 
whales and the Navy has specifically requested coverage for these 
species. Therefore, the likelihood of vessel strikes, and later the 
effects of the incidental take that is being authorized, has been fully 
analyzed and is described below.
    The quantitative analysis process used for the HSTT FEIS/OEIS and 
the Navy's take request in the rulemaking/LOA application to estimate 
potential exposures to marine mammals resulting from acoustic and 
explosive stressors is detailed in the technical report titled 
Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods 
and Analytical Approach for Phase III Training and Testing report (U.S. 
Department of the Navy, 2018). The Navy Acoustic Effects Model 
estimates acoustic and explosive effects without taking mitigation into 
account; therefore, the model overestimates predicted impacts on marine 
mammals within mitigation zones. To account for mitigation for marine 
species in the take estimates, the Navy conducts a quantitative 
assessment of mitigation. The Navy conservatively quantifies the manner 
in which mitigation is expected to reduce model-estimated PTS to TTS 
for exposures to sonar and other transducers, and reduce model-
estimated mortality to injury for exposures to explosives. The extent 
to which the mitigation areas reduce impacts on the affected species 
and stocks is addressed separately in the Analysis and Negligible 
Impact Determination section.
    The Navy assessed the effectiveness of its procedural mitigation 
measures on a per-scenario basis for four factors: (1) Species 
sightability, (2) a Lookout's ability to observe the range to PTS (for 
sonar and other transducers) and range to mortality (for explosives), 
(3) the portion of time when mitigation could potentially be conducted 
during periods of reduced daytime visibility (to include inclement 
weather and high sea-state) and the portion of time when mitigation 
could potentially be conducted at night, and (4) the ability for sound 
sources to be positively controlled (e.g., powered down).
    During training and testing activities, there is typically at least 
one, if not numerous, support personnel involved in the activity (e.g., 
range support personnel aboard a torpedo retrieval boat or support 
aircraft). In addition to the Lookout posted for the purpose of 
mitigation, these additional personnel observe and disseminate marine 
species sighting information amongst the units participating in the 
activity whenever possible as they conduct their primary mission 
responsibilities. However, as a conservative approach to assigning 
mitigation effectiveness factors, the Navy elected to only account for 
the minimum number of required Lookouts used for each activity; 
therefore, the mitigation effectiveness factors may underestimate the 
likelihood that some marine mammals may be detected during activities 
that are supported by additional personnel who may also be observing 
the mitigation zone.
    The Navy used the equations in the below sections to calculate the 
reduction in model-estimated mortality impacts due to implementing 
procedural mitigation.

Equation 1:
Mitigation Effectiveness = Species Sightability x Visibility x 
Observation Area x Positive Control

    Species Sightability is the ability to detect marine mammals and is 
dependent on the animal's presence at the surface and the 
characteristics of the animal that influence its sightability. The Navy 
considered applicable data from the best available science to 
numerically approximate the sightability of marine mammals and

[[Page 66938]]

determined the standard ``detection probability'' referred to as g(0) 
is most appropriate. Also, Visibility = 1 - sum of individual 
visibility reduction factors; Observation Area = portion of impact 
range that can be continuously observed during an event; and Positive 
Control = positive control factor of all sound sources involving 
mitigation. For further details on these mitigation effectiveness 
factors please refer to the technical report titled Quantifying 
Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and 
Analytical Approach for Phase III Training and Testing report (U.S. 
Department of the Navy, 2018).
    To quantify the number of marine mammals predicted to be sighted by 
Lookouts during implementation of procedural mitigation in the range to 
injury (PTS) for sonar and other transducers, the species sightability 
is multiplied by the mitigation effectiveness scores and number of 
model-estimated PTS impacts, as shown in the equation below:

Equation 2:
Number of Animals Sighted by Lookouts = Mitigation Effectiveness x 
Model-Estimated Impacts

    The marine mammals sighted by Lookouts during implementation of 
mitigation in the range to PTS, as calculated by the equation above, 
would avoid being exposed to these higher level impacts. To quantify 
the number of marine mammals predicted to be sighted by Lookouts during 
implementation of procedural mitigation in the range to mortality 
during events using explosives, the species sightability is multiplied 
by the mitigation effectiveness scores and number of model-estimated 
mortality impacts, as shown in equation 1 above. The marine mammals 
predicted to be sighted by Lookouts during implementation of procedural 
mitigation in the range to mortality, as calculated by the above 
equation 2, are predicted to avoid exposure in these ranges. The Navy 
corrects the category of predicted impact for the number of animals 
sighted within the mitigation zone, but does not modify the total 
number of animals predicted to experience impacts from the scenario. 
For example, the number of animals sighted (i.e., number of animals 
that will avoid mortality) is first subtracted from the model-predicted 
mortality impacts, and then added to the model-predicted injurious 
impacts.
    NMFS coordinated with the Navy in the development of this 
quantitative method to address the effects of procedural mitigation on 
acoustic and explosive exposures and takes, and NMFS independently 
reviewed and concurs with the Navy that it is appropriate to 
incorporate the quantitative assessment of mitigation into the take 
estimates based on the best available science. For additional 
information on the quantitative analysis process and mitigation 
measures, refer to the technical report titled Quantifying Acoustic 
Impacts on Marine Mammals and Sea Turtles: Methods and Analytical 
Approach for Phase III Training and Testing report (U.S. Department of 
the Navy, 2018) and Chapter 6 (Take Estimates for Marine Mammals) and 
Chapter 11 (Mitigation Measures) of the Navy's rulemaking/LOA 
application.
    In summary, we believe the Navy's methods, including the method for 
incorporating mitigation and avoidance, are the most appropriate 
methods for predicting PTS and TTS. But even with the consideration of 
mitigation and avoidance, given some of the more conservative 
components of the methodology (e.g., the thresholds do not consider ear 
recovery between pulses), we would describe the application of these 
methods as identifying the maximum number of instances in which marine 
mammals would be reasonably expected to incur either TTS or PTS.
Summary of Requested Take From Training and Testing Activities
    As a general matter, NMFS does not prescribe the methods for 
estimating take for any applicant, but we review and ensure that 
applicants use the best available science, and methodologies that are 
logical and technically sound. Applicants may use different methods of 
calculating take (especially when using models) and still get to a 
result that is representative of the best available science and that 
allows for a rigorous and accurate evaluation of the effects on the 
affected populations. There are multiple pieces of the Navy take 
estimation methods--propagation models, animat animal movement models, 
and behavioral thresholds, for example. NMFS evaluates the 
acceptability of these pieces as they evolve and are used in different 
rules and impact analyses. Some of the pieces of the Navy's take 
estimation process have been used in their rules since 2009 and 
undergone multiple public comment processes, all of them have undergone 
extensive internal Navy review, and all of them have undergone 
comprehensive review by NMFS, which has sometimes resulted in 
modifications to methods or models.
    The Navy uses rigorous review processes (verification, validation, 
and accreditation processes, peer and public review) to ensure the data 
and methodology it uses represent the best available science. For 
instance, the NAEMO (animal movement) model is the result of a NMFS-led 
Center for Independent Experts (CIE) review of the components used in 
earlier models. The acoustic propagation component of the NAEMO model 
(CASS/GRAB) is accredited by the Oceanographic and Atmospheric Master 
Library (OAML), and many of the environmental variables used in the 
NAEMO model come from approved OAML databases and are based on in-situ 
data collection. The animal density components of the NAEMO model are 
base products of the Navy Marine Species Density Database, which 
includes animal density components that have been validated and 
reviewed by a variety of scientists from NMFS Science Centers and 
academic institutions. Several components of the model, for example the 
Duke University habitat-based density models, have been published in 
peer reviewed literature. Others like AMAPPS, which was conducted by 
NMFS Science Centers, have undergone quality assurance and quality 
control (QA/QC) processes. Finally the NAEMO model simulation 
components underwent QA/QC review and validation for model parts such 
as the scenario builder, acoustic builder, scenario simulator, etc., 
conducted by qualified statisticians and modelers to ensure accuracy. 
Other models and methodologies have gone through similar review 
processes.
    Based on the methods discussed in the previous sections and the 
Navy's model and the quantitative assessment of mitigation, the Navy 
provided its take request for acoustic and explosive sources for 
training and testing activities both annually (based on the maximum 
number of activities per 12-month period) and over a 5-year period. 
NMFS has reviewed the Navy's data and analysis and determined that it 
is complete and accurate and that the takes by harassment as well as 
the takes by serious injury or mortality from explosives requested for 
authorization are reasonably expected to occur and that the takes by 
serious injury or mortality could occur as a result of vessel strikes. 
Five-year total impacts may be less than the sum total of each year 
because although the annual estimates are based on the maximum 
estimated takes, five-year estimates are based on the sum of two 
maximum years and three nominal years.

[[Page 66939]]

Authorized Take From Training Activities
    For training activities, Table 41 summarizes the Navy's take 
request and the maximum amount and type of Level A and Level B 
harassment that NMFS concurs is reasonably likely to occur by species 
or stock. Authorized mortality is addressed further below. Navy Figures 
6-12 through 6-50 in Chapter 6 of the Navy's rulemaking/LOA application 
illustrate the comparative amounts of TTS and Level B behavioral 
harassment for each species, noting that if a ``taken'' animat was 
exposed to both TTS and Level B behavioral harassment, it was recorded 
as a TTS.

Table 41--Species and Stock-Specific Take From Acoustic and Explosive Effects for All Training Activities in the
                                                 HSTT Study Area
----------------------------------------------------------------------------------------------------------------
                                                              Annual                      5-Year total **
                                                 ---------------------------------------------------------------
            Species                   Stock           Level B         Level A         Level B         Level A
                                                    harassment      harassment      harassment      harassment
----------------------------------------------------------------------------------------------------------------
                                       Suborder Mysticeti (baleen whales)
----------------------------------------------------------------------------------------------------------------
                                        Family Balaenopteridae (rorquals)
----------------------------------------------------------------------------------------------------------------
Blue whale *..................  Central North                 34               0             139               0
                                 Pacific.
                                Eastern North              1,155               1           5,036               3
                                 Pacific.
Bryde's whale [dagger]........  Eastern Tropical              27               0             118               0
                                 Pacific.
                                Hawaii [dagger].             105               0             429               0
Fin whale *...................  CA/OR/WA........           1,245               0           5,482               0
                                Hawaii..........              33               0             133               0
Humpback whale [dagger].......  CA/OR/WA                   1,254               1           5,645               3
                                 [dagger].
                                Central North              5,604               1          23,654               6
                                 Pacific.
Minke whale...................  CA/OR/WA........             649               1           2,920               4
                                Hawaii..........           3,463               1          13,664               2
Sei whale *...................  Eastern North                 53               0             236               0
                                 Pacific.
                                Hawaii..........             118               0             453               0
----------------------------------------------------------------------------------------------------------------
                                              Family Eschrichtiidae
----------------------------------------------------------------------------------------------------------------
Gray whale [dagger]...........  Eastern North              2,751               5          11,860              19
                                 Pacific.
                                Western North                  4               0              14               0
                                 Pacific
                                 [dagger].
----------------------------------------------------------------------------------------------------------------
                                      Suborder Odontoceti (toothed whales)
----------------------------------------------------------------------------------------------------------------
                                        Family Physeteridae (sperm whale)
----------------------------------------------------------------------------------------------------------------
Sperm whale *.................  CA/OR/WA........           1,397               0           6,257               0
                                Hawaii..........           1,714               0           7,078               0
----------------------------------------------------------------------------------------------------------------
                                         Family Kogiidae (sperm whales)
----------------------------------------------------------------------------------------------------------------
Dwarf sperm whale.............  Hawaii..........          13,961              35          57,571             148
Pygmy sperm whale.............  Hawaii..........           5,556              16          22,833              64
Kogia whales..................  CA/OR/WA........           6,012              23          27,366             105
----------------------------------------------------------------------------------------------------------------
                                        Family Ziphiidae (beaked whales)
----------------------------------------------------------------------------------------------------------------
Baird's beaked whale..........  CA/OR/WA........           1,317               0           6,044               0
Blainville's beaked whale.....  Hawaii..........           3,687               0          16,364               0
Cuvier's beaked whale.........  CA/OR/WA........           7,016               0          33,494               0
                                Hawaii..........           1,235               0           5,497               0
Longman's beaked whale........  Hawaii..........          13,010               0          57,172               0
Mesoplodon spp................  CA/OR/WA........           3,778               0          18,036               0
----------------------------------------------------------------------------------------------------------------
                                          Family Delphinidae (dolphins)
----------------------------------------------------------------------------------------------------------------
Bottlenose dolphin............  California                   214               0             876               0
                                 Coastal.
                                CA/OR/WA                  31,986               2         142,966               9
                                 Offshore.
                                Hawaii Pelagic..           2,086               0           9,055               0
                                Kauai & Niihau..              74               0             356               0
                                Oahu............           8,186               1          40,918               7
                                4-Island........             152               0             750               0
                                Hawaii Island...              42               0             207               0
False killer whale [dagger]...  Hawaii Pelagic..             701               0           3,005               0
                                Main Hawaiian                405               0           1,915               0
                                 Islands Insular
                                 [dagger].
                                Northwestern                 256               0           1,094               0
                                 Hawaiian
                                 Islands.
Fraser's dolphin..............  Hawaii..........          28,409               1         122,784               3
Killer whale..................  Eastern North                 73               0             326               0
                                 Pacific
                                 Offshore.
                                Eastern North                135               0             606               0
                                 Pacific
                                 Transient/West
                                 Coast Transient.
                                Hawaii..........              84               0             352               0

[[Page 66940]]

 
Long-beaked common dolphin....  California......         128,994              14         559,540              69
Melon-headed whale............  Hawaiian Islands           2,335               0           9,705               0
                                Kohala Resident.             182               0             913               0
Northern right whale dolphin..  CA/OR/WA........          56,820               8         253,068              40
Pacific white-sided dolphin...  CA/OR/WA........          43,914               3         194,882              12
Pantropical spotted dolphin...  Hawaii Island...           2,585               0          12,603               0
                                Hawaii Pelagic..           6,809               0          29,207               0
                                Oahu............           4,127               0          20,610               0
                                4-Island........             260               0           1,295               0
Pygmy killer whale............  Hawaii..........           5,816               0          24,428               0
                                Tropical........             471               0           2,105               0
Risso's dolphin...............  CA/OR/WA........          76,276               6         338,560              30
                                Hawaii..........           6,590               0          28,143               0
Rough-toothed dolphin.........  Hawaii..........           4,292               0          18,506               0
                                NSD \1\.........               0               0               0               0
Short-beaked common dolphin...  CA/OR/WA........         932,453              45       4,161,283             216
Short-finned pilot whale......  CA/OR/WA........             990               1           4,492               5
                                Hawaii..........           8,594               0          37,077               0
Spinner dolphin...............  Hawaii Island...              89               0             433               0
                                Hawaii Pelagic..           3,138               0          12,826               0
                                Kauai & Niihau..             310               0           1,387               0
                                Oahu & 4-Island.           1,493               1           7,445               5
Striped dolphin...............  CA/OR/WA........         119,219               1         550,936               3
                                Hawaii..........           5,388               0          22,526               0
----------------------------------------------------------------------------------------------------------------
                                         Family Phocoenidae (porpoises)
----------------------------------------------------------------------------------------------------------------
Dall's porpoise...............  CA/OR/WA........          27,282             137         121,256             634
----------------------------------------------------------------------------------------------------------------
                                               Suborder Pinnipedia
----------------------------------------------------------------------------------------------------------------
                                         Family Otariidae (eared seals)
----------------------------------------------------------------------------------------------------------------
California sea lion...........  U.S.............          69,543              90         327,136             447
Guadalupe fur seal *..........  Mexico..........             518               0           2,386               0
Northern fur seal.............  California......           9,786               0          44,017               0
----------------------------------------------------------------------------------------------------------------
                                          Family Phocidae (true seals)
----------------------------------------------------------------------------------------------------------------
Harbor seal...................  California......           3,119               7          13,636              34
Hawaiian monk seal *..........  Hawaii..........             139               1             662               3
Northern elephant seal........  California......          38,169              72         170,926             349
----------------------------------------------------------------------------------------------------------------
Note: Kogia: Pygmy and dwarf sperm whales are difficult to distinguish between at sea, and abundance estimates
  are only available for Kogia spp (reported in Barlow 2016 and Carretta et al. 2017). Due to low estimated
  abundances of CA/OR/WA dwarf sperm whales, the majority of Kogia in the HSTT Study Area are anticipated to be
  CA/OR/WA pygmy sperm whales.
Mesoplodon: No methods are available to distinguish between the six species of Mesoplodon beaked whales in the
  CA/OR/WA 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). These six species are managed as one unit.
* ESA-listed species (all stocks) within the HSTT Study Area.
** 5-year total impacts may be less than sum total of each year. Not all activities occur every year; some
  activities occur multiple times within a year; and some activities only occur a few times over course of a 5-
  year period.
[dagger] Only designated stocks are ESA-listed.
\1\ NSD: No stock designation.

Authorized Take From Testing Activities
    For testing activities, Table 42 summarizes the Navy's take request 
and the maximum amount and type of take by Level A and Level B 
harassment that NMFS concurs is reasonably likely to occur and has 
authorized by species or stock. Navy Figures 6-12 through 6-50 in 
Chapter 6 of the Navy's rulemaking/LOA application illustrate the 
comparative amounts of TTS and Level B behavioral harassment for each 
species, noting that if a ``taken'' animat was exposed to both TTS and 
Level B behavioral harassment in the model, it was recorded as a TTS.

[[Page 66941]]



   Table 42--Species and Stock-Specific Take From Acoustic and Explosive Sound Source Effects for All Testing
                                        Activities in the HSTT Study Area
----------------------------------------------------------------------------------------------------------------
                                                              Annual                      5-year total **
                                                 ---------------------------------------------------------------
            Species                   Stock           Level B         Level A         Level B         Level A
                                                    harassment      harassment      harassment      harassment
----------------------------------------------------------------------------------------------------------------
                                       Suborder Mysticeti (baleen whales)
----------------------------------------------------------------------------------------------------------------
                                        Family Balaenopteridae (rorquals)
----------------------------------------------------------------------------------------------------------------
Blue whale *..................  Central North                 14               0              65               0
                                 Pacific.
                                Eastern North                833               0           4,005               0
                                 Pacific.
Bryde's whale [dagger]........  Eastern Tropical              14               0              69               0
                                 Pacific.
                                Hawaii [dagger].              41               0             194               0
Fin whale *...................  CA/OR/WA........             980               1           4,695               3
                                Hawaii..........              15               0              74               0
Humpback whale [dagger].......  CA/OR/WA                     740               0           3,508               0
                                 [dagger].
                                Central North              3,522               2          16,777              11
                                 Pacific.
Minke whale...................  CA/OR/WA........             276               0           1,309               0
                                Hawaii..........           1,467               1           6,918               4
Sei whale *...................  Eastern North                 26               0             124               0
                                 Pacific.
                                Hawaii..........              49               0             229               0
----------------------------------------------------------------------------------------------------------------
                                              Family Eschrichtiidae
----------------------------------------------------------------------------------------------------------------
Gray whale [dagger]...........  Eastern North              1,920               2           9,277               7
                                 Pacific.
                                Western North                  2               0              11               0
                                 Pacific
                                 [dagger].
----------------------------------------------------------------------------------------------------------------
                                      Suborder Odontoceti (toothed whales)
----------------------------------------------------------------------------------------------------------------
                                        Family Physeteridae (sperm whale)
----------------------------------------------------------------------------------------------------------------
Sperm whale *.................  CA/OR/WA........           1,096               0           5,259               0
                                Hawaii..........             782               0           3,731               0
----------------------------------------------------------------------------------------------------------------
                                         Family Kogiidae (sperm whales)
----------------------------------------------------------------------------------------------------------------
Dwarf sperm whale.............  Hawaii..........           6,459              29          30,607             140
Pygmy sperm whale.............  Hawaii..........           2,595              13          12,270              60
Kogia whales..................  CA/OR/WA........           3,120              15          14,643              67
----------------------------------------------------------------------------------------------------------------
                                        Family Ziphiidae (beaked whales)
----------------------------------------------------------------------------------------------------------------
Baird's beaked whale..........  CA/OR/WA........             727               0           3,418               0
Blainville's beaked whale.....  Hawaii..........           1,698               0           8,117               0
Cuvier's beaked whale.........  CA/OR/WA........           4,484               1          21,379              20
                                Hawaii..........             561               0           2,675               0
Longman's beaked whale........  Hawaii..........           6,223               0          29,746               0
Mesoplodon spp................  CA/OR/WA........           2,415               1          11,512              11
----------------------------------------------------------------------------------------------------------------
                                          Family Delphinidae (dolphins)
----------------------------------------------------------------------------------------------------------------
Bottlenose dolphin............  California                 1,595               0           7,968               0
                                 Coastal.
                                CA/OR/WA                  23,436               1         112,410               4
                                 Offshore.
                                Hawaii Pelagic..           1,242               0           6,013               0
                                Kauai & Niihau..             491               0           2,161               0
                                Oahu............             475               0           2,294               0
                                4-Island........             207               0             778               0
                                Hawaii Island...              38               0             186               0
False killer whale [dagger]...  Hawaii Pelagic..             340               0           1,622               0
                                Main Hawaiian                184               0             892               0
                                 Islands Insular
                                 [dagger].
                                Northwestern                 125               0             594               0
                                 Hawaiian
                                 Islands.
Fraser's dolphin..............  Hawaii..........          12,664               1          60,345               6
Killer whale..................  Eastern North                 34               0             166               0
                                 Pacific
                                 Offshore.
                                Eastern North                 64               0             309               0
                                 Pacific
                                 Transient/West
                                 Coast Transient.
                                Hawaii..........              40               0             198               0
Long-beaked common dolphin....  California......         118,278               6         568,020              24
Melon-headed whale............  Hawaiian Islands           1,157               0           5,423               0
                                Kohala Resident.             168               0             795               0
Northern right whale dolphin..  CA/OR/WA........          41,279               3         198,917              15
Pacific white-sided dolphin...  CA/OR/WA........          31,424               2         151,000               8
Pantropical spotted dolphin...  Hawaii Island...           1,409               0           6,791               0
                                Hawaii Pelagic..           3,640               0          17,615               0
                                Oahu............             202               0             957               0

[[Page 66942]]

 
                                4-Island........             458               0           1,734               0
Pygmy killer whale............  Hawaii..........           2,708               0          13,008               0
                                Tropical........             289               0           1,351               0
Risso's dolphin...............  CA/OR/WA........          49,985               3         240,646              16
                                Hawaii..........           2,808               0          13,495               0
Rough-toothed dolphin.........  Hawaii..........           2,193               0          10,532               0
                                NSD \1\.........               0               0               0               0
Short-beaked common dolphin...  CA/OR/WA........         560,120              44       2,673,431             216
Short-finned pilot whale......  CA/OR/WA........             923               0           4,440               0
                                Hawaii..........           4,338               0          20,757               0
Spinner dolphin...............  Hawaii Island...             202               0             993               0
                                Hawaii Pelagic..           1,396               0           6,770               0
                                Kauai & Niihau..           1,436               0           6,530               0
                                Oahu & 4-Island.             331               0           1,389               0
Striped dolphin...............  CA/OR/WA........          56,035               2         262,973              11
                                Hawaiian........           2,396               0          11,546               0
----------------------------------------------------------------------------------------------------------------
                                         Family Phocoenidae (porpoises)
----------------------------------------------------------------------------------------------------------------
Dall's porpoise...............  CA/OR/WA........          17,091              72          81,611             338
----------------------------------------------------------------------------------------------------------------
                                               Suborder Pinnipedia
----------------------------------------------------------------------------------------------------------------
                                         Family Otariidae (eared seals)
----------------------------------------------------------------------------------------------------------------
California sea lion...........  U.S.............          48,665               6         237,870              23
Guadalupe fur seal *..........  Mexico..........             939               0           4,357               0
Northern fur seal.............  California......           5,505               1          26,168               4
----------------------------------------------------------------------------------------------------------------
                                          Family Phocidae (true seals)
----------------------------------------------------------------------------------------------------------------
Harbor seal...................  California......           2,325               1          11,258               7
Hawaiian monk seal *..........  Hawaii..........              66               0             254               0
Northern elephant seal........  California......          22,702              27         107,343             131
----------------------------------------------------------------------------------------------------------------
Note: Kogia: Pygmy and dwarf sperm whales are difficult to distinguish between at sea, and abundance estimates
  are only available for Kogia spp (reported in Barlow 2016 and Carretta et al. 2017). Due to low estimated
  abundances of CA/OR/WA dwarf sperm whales, the majority of Kogia in the HSTT Study Area are anticipated to be
  CA/OR/WA pygmy sperm whales.
Mesoplodon: No methods are available to distinguish between the six species of Mesoplodon beaked whales in the
  CA/OR/WA 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). These six species are managed as one unit.
* ESA-listed species (all stocks) within the HSTT Study Area.
** 5-year total impacts may be less than sum total of each year. Not all activities occur every year; some
  activities occur multiple times within a year; and some activities only occur a few times over course of a 5-
  year period.
[dagger] Only designated stocks are ESA-listed.
\1\ NSD: No stock designation.

Take From Vessel Strikes and Explosives by Serious Injury or Mortality
Vessel Strike
    Vessel strikes from commercial, recreational, and military vessels 
are known to affect large whales and have resulted in serious injury 
and occasional fatalities to cetaceans (Berman-Kowalewski et al., 2010; 
Calambokidis, 2012; Douglas et al., 2008; Laggner 2009; Lammers et al., 
2003). Records of collisions date back to the early 17th century, and 
the worldwide number of collisions appears to have increased steadily 
during recent decades (Laist et al., 2001; Ritter 2012).
    Numerous studies of interactions between surface vessels and marine 
mammals have demonstrated that free-ranging marine mammals often, but 
not always (e.g., McKenna et al., 2015), engage in avoidance behavior 
when surface vessels move toward them. It is not clear whether these 
responses are caused by the physical presence of a surface vessel, the 
underwater noise generated by the vessel, or an interaction between the 
two (Amaral and Carlson, 2005; Au and Green, 2000; Bain et al., 2006; 
Bauer, 1986; Bejder et al., 1999; Bejder and Lusseau, 2008; Bejder et 
al., 2009; Bryant et al., 1984; Corkeron, 1995; Erbe, 2002; 
F[eacute]lix, 2001; Goodwin and Cotton, 2004; Lemon et al., 2006; 
Lusseau, 2003; Lusseau, 2006; Magalhaes et al., 2002; Nowacek et al., 
2001; Richter et al., 2003; Scheidat et al., 2004; Simmonds, 2005; 
Watkins, 1986; Williams et al., 2002; Wursig et al., 1998). Several 
authors suggest that the noise generated during motion is probably an 
important factor (Blane and Jaakson, 1994; Evans et al., 1992; Evans et 
al., 1994). Water disturbance may also be a factor. These studies 
suggest that the behavioral responses of marine mammals to surface 
vessels are similar to their behavioral responses to predators. 
Avoidance behavior is expected to be even stronger in the subset of 
instances that the Navy is

[[Page 66943]]

conducting training or testing activities using active sonar or 
explosives.
    The most vulnerable marine mammals are those that spend extended 
periods of time at the surface in order to restore oxygen levels within 
their tissues after deep dives (e.g., sperm whales). In addition, some 
baleen whales seem generally unresponsive to vessel sound, making them 
more susceptible to vessel collisions (Nowacek et al., 2004). These 
species are primarily large, slow moving whales.
    Some researchers have suggested the relative risk of a vessel 
strike can be assessed as a function of animal density and the 
magnitude of vessel traffic (e.g., Fonnesbeck et al., 2008; Vanderlaan 
et al., 2008). Differences among vessel types also influence the 
probability of a vessel strike. The ability of any ship to detect a 
marine mammal and avoid a collision depends on a variety of factors, 
including environmental conditions, ship design, size, speed, and 
ability and number of personnel observing, as well as the behavior of 
the animal. Vessel speed, size, and mass are all important factors in 
determining if injury or death of a marine mammal is likely due to a 
vessel strike. For large vessels, speed and angle of approach can 
influence the severity of a strike. For example, Vanderlaan and Taggart 
(2007) found that between vessel speeds of 8.6 and 15 knots, the 
probability that a vessel strike is lethal increases from 0.21 to 0.79. 
Large whales also do not have to be at the water's surface to be 
struck. Silber et al. (2010) found when a whale is below the surface 
(about one to two times the vessel draft), there is likely to be a 
pronounced propeller suction effect. This suction effect may draw the 
whale into the hull of the ship, increasing the probability of 
propeller strikes.
    There are some key differences between the operation of military 
and non-military vessels, which make the likelihood of a military 
vessel striking a whale lower than some other vessels (e.g., commercial 
merchant vessels). Key differences include:

    [ssquf] Many military ships have their bridges positioned closer 
to the bow, offering better visibility ahead of the ship (compared 
to a commercial merchant vessel).
    [ssquf] There are often aircraft associated with the training or 
testing activity (which can serve as Lookouts), which can more 
readily detect cetaceans in the vicinity of a vessel or ahead of a 
vessel's present course before crew on the vessel would be able to 
detect them.
    [ssquf] Military ships are generally more maneuverable than 
commercial merchant vessels, and if cetaceans are spotted in the 
path of the ship, could be capable of changing course more quickly.
    [ssquf] The crew size on military vessels is generally larger 
than merchant ships, allowing for stationing more trained Lookouts 
on the bridge. At all times when vessels are underway, trained 
Lookouts and bridge navigation teams are used to detect objects on 
the surface of the water ahead of the ship, including cetaceans. 
Additional Lookouts, beyond those already stationed on the bridge 
and on navigation teams, are positioned as Lookouts during some 
training events.
    [ssquf] When submerged, submarines are generally slow moving (to 
avoid detection) and therefore marine mammals at depth with a 
submarine are likely able to avoid collision with the submarine. 
When a submarine is transiting on the surface, there are Lookouts 
serving the same function as they do on surface ships.

    Vessel strike to marine mammals is not associated with any specific 
training or testing activity but is rather an extremely limited and 
sporadic, but possible, accidental result of Navy vessel movement 
within the HSTT Study Area or while in transit.
    There have been two recorded Navy vessel strikes of large whales in 
the HSTT Study Area from 2009 through 2018, the period in which Navy 
began implementing effective mitigation measures to reduce the 
likelihood of vessel strikes. Both strikes occured in 2009 and both 
were to fin whales. In order to account for the accidental nature of 
vessel strikes to large whales in general, and the potential risk from 
any vessel movement within the HSTT Study Area within the five-year 
period in particular, the Navy requested incidental takes based on 
probabilities derived from a Poisson distribution using ship strike 
data between 2009-2016 in the HSTT Study Area (the time period from 
when current mitigations were instituted until the Navy conducted the 
analysis for the EIS/OEIS and rulemaking/LOA application; no new 
strikes have occurred since), as well as historical at-sea days in the 
HSTT Study Area from 2009-2016 and estimated potential at-sea days for 
the period from 2018 to 2023 covered by the requested regulations. This 
distribution predicted the probabilities of a specific number of 
strikes (n=0, 1, 2, etc.) over the period from 2018 to 2023. The 
analysis is described in detail in Chapter 6 of the Navy's rulemaking/
LOA application (and further refined in the Navy's revised ship strike 
analysis posted on NMFS' website https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities).
    For the same reasons listed above describing why a Navy vessel 
strike is comparatively unlikely, it is highly unlikely that a Navy 
vessel would strike a whale, dolphin, porpoise, or pinniped without 
detecting it and, accordingly, NMFS is confident that the Navy's 
reported strikes are accurate and appropriate for use in the analysis. 
Specifically, Navy ships have multiple Lookouts, including on the 
forward part of the ship that can visually detect a hit animal, in the 
unlikely event ship personnel do not feel the strike (which has 
occasionally occurred). Navy's strict internal procedures and 
mitigation requirements include reporting of any vessel strikes of 
marine mammals, and the Navy's discipline, extensive training (not only 
for detecting marine mammals, but for detecting and reporting any 
potential navigational obstruction), and strict chain of command give 
NMFS a high level of confidence that all strikes actually get reported.
    The Navy used those two fin whale strikes in their calculations to 
determine the number of strikes likely to result from their activities 
(although worldwide strike information, from all Navy activities and 
other strikes, was used to inform the species that may be struck) and 
evaluated data beginning in 2009, as that was the start of the Navy's 
Marine Species Awareness Training and adoption of additional mitigation 
measures to address ship strike, which will remain in place along with 
additional mitigation measures during the five years of this rule.
    The probability analysis concluded that there was a 29 percent 
chance that zero whales would be struck by Navy vessels over the five-
year period, indicating a 71 percent chance that at least one whale 
would be struck over the five years and a 10 percent chance of striking 
three whales over the five-year period. Therefore, the Navy estimates, 
and NMFS agrees, that there is some probability that the Navy could 
strike, and take by serious injury or mortality, up to three large 
whales incidental to training and testing activities within the HSTT 
Study Area over the course of the five years.
    Small delphinids, porpoises, and pinnipeds are neither expected nor 
authorized to be struck by Navy vessels. In addition to the reasons 
listed above that make it unlikely that the Navy will hit a large whale 
(more maneuverable ships, larger crew, etc.), following are the 
additional reasons that vessel strike of dolphins, small whales, 
porpoises, and pinnipeds is considered very unlikely. Dating back more 
than 20 years and for as long as it has kept records, the Navy has no 
records of individuals of these groups being struck by a vessel as a 
result of Navy activities

[[Page 66944]]

and, further, their smaller size and maneuverability make a strike 
unlikely. Also, NMFS has never received any reports from other 
authorized activities indicating that these species have been struck by 
vessels. Worldwide ship strike records show little evidence of strikes 
of these groups from the shipping sector and larger vessels and the 
majority of the Navy's activities involving faster-moving vessels (that 
could be considered more likely to hit a marine mammal) are located in 
offshore areas where smaller delphinid, porpoise, and pinniped 
densities are lower. Based on this information, NMFS concurs with the 
Navy's assessment and recognizes the potential for (and is authorizing) 
incidental take by vessel strike of large whales only (i.e., no 
dolphins, small whales, porpoises, or pinnipeds) over the course of the 
five-year regulations from training and testing activities as discussed 
below.
    For large whales, the Navy's application identified the 
distribution of species over which the take request would apply based 
on the species/stocks most likely to be present in the HSTT Study Area 
based on documented abundance and where overlap occurs between a 
species' distribution and core Navy training and testing areas within 
the HSTT Study Area. To determine which species may be struck, the Navy 
used a weight of evidence approach to qualitatively rank range complex 
specific species using historic and current stranding data from NMFS, 
relative abundance as derived by NMFS for the HSTT Biological Opinion, 
and the Navy-funded monitoring data within each range complex. Results 
of this approach are presented in Table 5-4 of the Navy's rulemaking/
LOA application.
    Based on the analysis described above and in its application, the 
Navy estimated that it has the potential to strike, and take by serious 
injury or mortality, up to three large whales incidental to the 
specified activity over the course of the five years of the HSTT 
regulations. The Navy initially requested incidental take authorization 
for up to two of any the following stocks in the five-year period: gray 
whale (Eastern North Pacific stock), fin whale (CA/OR/WA stock), 
humpback whale (CA/OR/WA stock, Mexico DPS), humpback whale (Central 
North Pacific stock), and sperm whale (Hawaii stock). The Navy also 
initially requested incidental take authorization for one of any the 
following species over the five-year period: blue whale (Eastern North 
Pacific stock), Bryde's whale (Eastern Tropical Pacific stock), Bryde's 
whale (Hawaii stock), humpback whale (CA/OR/WA stock, Central America 
DPS), minke whale (CA/OR/WA stock), minke whale (Hawaii stock), sperm 
whale (CA/OR/WA stock), sei whale (Hawaii stock), and sei whale 
(Eastern North Pacific stock).
    NMFS independently reviewed this analysis and agrees that three 
ship strikes have at least the potential to occur and, therefore, that 
the request for mortal takes of three large whales over the five-year 
period of the rule is reasonable based on the available strike data 
(two strikes by Navy over approximately 10 years) and the Navy's 
probability analysis. Based on the reasons described below, however, 
NMFS does not agree that two mortal takes of humpback whale (CA/OR/WA 
stock) or sperm whales are likely, or that any strike of the following 
whale species is remotely likely: Minke whale (CA/OR/WA stock), minke 
whale (Hawaii stock), sei whale (Hawaii stock), sei whale (Eastern 
North Pacific stock), Bryde's whale (Eastern Tropical Pacific stock), 
sperm whale (CA/OR/WA stock) and Bryde's whale (Hawaii stock).
    Since the proposed rule was published, NMFS and the Navy re-
examined and re-analyzed the available information regarding how many 
of any given stock could be struck and should be authorized for lethal 
take. As noted in the proposed rule, the Navy initially considered a 
weight of evidence approach that considered relative abundance, 
historical strike data over many years, and the overlap of Navy 
activities with the stock distribution in their request. Since the 
proposed rule, NMFS and the Navy further discussed the available 
information and considered two factors in addition to those considered 
in the Navy's additional request: (1) The relative likelihood of 
hitting one stock versus another based on available strike data from 
all vessel types as denoted in the SARs and (2) whether the Navy has 
ever definitively struck an individual from a particular stock and, if 
so, how many times.
    To address number (1) above, NMFS compiled information from NMFS' 
SARs on detected annual rates of large whale serious injury and 
mortality from vessel collisions. The annual rates of large whale 
serious injury and mortality from vessel collisions from the SARs help 
inform the relative susceptibility of large whale species to vessel 
strike in SOCAL and Hawaii as recorded systematically over the last 
five years. We summed the annual rates of mortality and serious injury 
from vessel collisions as reported in the SARs, then divided each 
species' annual rate by this sum to get the relative likelihood. To 
estimate the percent likelihood of striking a particular species of 
large whale, we multiplied the relative likelihood of striking each 
species by the total probability of striking a whale (i.e., 71 percent, 
as described by the Navy's probability analysis above). We also 
calculated the percent likelihood of striking a particular species of 
large whale twice by squaring the value estimated for the probability 
of striking a particular species of whale once (i.e., to calculate the 
probability of an event occurring twice, multiply the probability of 
the first event by the second). We note that these probabilities vary 
from year to year as the average annual mortality for a given five-year 
window changes (and we include the annual averages from 2017 and 2018 
SARs in Table 43 to illustrate), however, over the years and through 
changing SARs, stocks tend to consistently maintain a relatively higher 
or relatively lower likelihood of being struck.
    The probabilities calculated as described above are then considered 
in combination with the information indicating the species that the 
Navy has definitively hit in the HSTT Study Area since 1991 (since they 
started tracking consistently), as well as the information originally 
considered by the Navy in their application, which includes relative 
abundance, total recorded strikes, and the overlay of all of this 
information with the Navy's action area. We note that for all of the 
mortal take of species specifically denoted in Table 43 below, 19 
percent of the individuals struck overall by any vessel type remained 
unidentified and 36 percent of those struck by the Navy (5 of 14 in the 
Pacific) remained unidentified. However, given the information on known 
stocks struck, the analysis below remains appropriate. We also note 
that Rockwood et al. (2017) modeled the likely vessel strike of blue 
whales, fin whales, and humpback whales on the U.S. West Coast 
(discussed in more detail in the Serious Injury and Mortality 
subsection of the Analysis and Negligible Impact Determination 
section), and those numbers help inform the relative likelihood that 
the Navy will hit those stocks.
    For each indicated stock, Table 43 includes the percent likelihood 
of hitting an individual whale once based on SAR data, total strikes 
from Navy vessels and from all other vessels, relative abundance, and 
modeled vessel strikes from Rockwood et al. The last column indicates 
the annual mortality authorized: those stocks with one M/SI take 
authorized over the five-year period of the rule are shaded lightly, 
while those with two M/SI takes authorized

[[Page 66945]]

over the five-year period of the rule are shaded more darkly.
[GRAPHIC] [TIFF OMITTED] TR27DE18.025

    Accordingly, stocks that have no record of ever having been struck 
by any vessel are considered unlikely to be struck by the Navy in the 
five-year period of the rule. Stocks that have never been struck by the 
Navy, have rarely been struck by other vessels, and have a low percent 
likelihood based on the SAR calculation and a low relative abundance 
are also considered unlikely to be struck by the Navy during the five-
year rule. We note that while vessel strike records have not 
differentiated between Eastern North Pacific and Western North Pacific 
gray whales, given their small population size and the comparative 
rarity with which individuals from the Western North Pacific stock are 
detected off the U.S. West Coast, it is highly unlikely that they would 
be encountered, much less struck. This rules out all but six stocks.
    Three of the six stocks (CA/OR/WA stock of fin whale, Eastern North 
Pacific stock of gray whale, and Central North Pacific stock of 
humpback whale) are the only stocks to have been hit more than one time 
each by the Navy in the HSTT StudyAarea, have the three highest total 
strike records (21, 35, and 58 respectively), have three of the four 
highest percent likelihoods based on the SAR records, have three of the 
four significantly higher relative abundances, and have up to a 3 or 4 
percent likelihood of being struck twice based on NMFS' SAR calculation 
(not shown in Table 43, but proportional to percent likelihood of being 
struck once). Based on all of these factors, it is considered 
reasonably likely that these stocks could be struck twice during the 
five-year rule.
    Based on the information summarized in Table 43 and the fact that 
we expect three large whales could be struck, it is considered 
reasonably likely that one individual from the remaining three stocks 
could be struck. Sperm whales have only been struck a total of two 
times by any vessel type in the whole HSTT Study Area, however, the 
Navy struck a sperm whale once in Hawaii prior to 2009 and the relative 
abundance of sperm whales in Hawaii is the highest of any of the stocks 
present. Therefore, we consider it reasonably likely that the Hawaii 
stock of sperm whales could be struck once during the five-year rule. 
The total strikes of Eastern North Pacific blue whales, the percent 
likelihood of striking one based on the SAR calculation, and their 
relative abundance can all be considered moderate compared to other 
stocks and the Navy has struck one in the past prior to 2009 (with the 
likelihood of striking two based on the SAR calculation being below one 
percent). Therefore, we consider it reasonably likely that the Navy 
could strike one individual over the course of the five-year rule. The 
Navy has not hit a humpback whale in the HSTT Study Area and their 
relative abundance is very low. However, the Navy has struck a humpback 
whale in the Northwest and as a species, humpbacks have a moderate to 
high number of total strikes and percent likelihood of being struck. 
Although the likelihood of CA/OR/WA humpback whales being struck 
overall is moderate to high relative to other stocks, the distribution 
of the Mexico DPS versus the Central America DPS, as well as the 
distribution of overall vessel strikes inside versus outside of the 
SOCAL area (the majority are outside), supports the reasonable 
likelihood that the Navy could strike one individual humpback whale 
(not two), and that that

[[Page 66946]]

individual would be highly likely to be from the Mexico DPS, as 
described below.
    Specifically, regarding the likelihood of striking a humpback whale 
from a particular DPS, as suggested in Wade et al. (2016), the 
probability of encountering (which is thereby applied to striking) 
humpback whales from each DPS in the CA/OR area is 89.6 percent and 
19.7 percent for the Mexico and Central America DPSs, respectively 
(note that these percentages reflect the upper limit of the 95 percent 
confidence interval to reduce the likelihood of underestimating take, 
and thereby do not total to 100). This suggests that the chance of 
striking a whale from the Central America DPS is one tenth to one fifth 
of the overall chance of hitting a CA/OR/WA humpback whale in general 
in the SOCAL part of the HSTT Study Area, which in combination with the 
fact that no humpback whale has been struck in SOCAL makes it highly 
unlikely, and thereby none from the Central America DPS are anticipated 
or authorized. If a humpback whale were struck in SOCAL, it is likely 
it would be of the Mexico DPS. However, regarding the overall 
likelihood of striking a humpback whale at all and the likely number of 
times, we note that the majority of strikes of the CA/OR/WA humpback 
whale (i.e., the numbers reflected in Table 43) take place outside of 
SOCAL and, whereas the comparative DPS numbers cited above apply in the 
California and Oregon feeding area, in the Washington and Southern 
British Columbia feeding area, Wade et al. (2016) suggest that 52.9, 
41.9, and 14.7 percent of humpback whales encountered will come from 
the Hawaii, Mexico, and Central America DPSs, respectively. This means 
that the numbers in Table 43 indicating the overall strikes of CA/OR/WA 
humpback whales and SAR calculations based on average annual mortality 
over the last five years are actually lower than indicated for the 
Mexico DPS, which would only be a subset of those mortalities. Last, 
the Rockwood et al. paper supports a relative likelihood of 1:1:2 for 
striking blue whales, humpback whales, and fin whales off the U.S. West 
Coast, which supports the authorized take included in this rule, which 
is 1, 1, and 2, respectively over the five-year period. For these 
reasons, one mortal take of CA/OR/WA humpback whales, which would be 
expected to be of the Mexico DPS, could reasonably likely occur and is 
authorized.
    Accordingly, the Navy revised their request for take by serious 
injury or mortality to include up to two of any the following species 
in the five-year period: Gray whale (Eastern North Pacific stock), fin 
whale (CA/OR/WA stock), humpback whale (Central North Pacific stock); 
and one of any of the following species in the five year period: Blue 
whale (Eastern North Pacific stock), humpback whale (CA/OR/WA stock, 
Mexico DPS), or sperm whale (Hawaii stock).
    As described above, NMFS and the Navy concur that vessel strikes to 
the stocks below are very unlikely to occur due to the stocks' 
relatively low occurrence in the HSTT Study Area, particularly in core 
HSTT training and testing subareas, and the fact that the stocks have 
not been struck by the Navy and are rarely, if ever, recorded struck by 
other vessels. Therefore the Navy is not requesting lethal take 
authorization, and NMFS is not authorizing lethal take, for the 
following stocks: Bryde's whale (Eastern Tropical Pacific stock), 
Bryde's whale (Hawaii stock), humpback whale (CA/OR/WA stock, Central 
America DPS), minke whale (CA/OR/WA stock), minke whale (Hawaii stock), 
sei whale (Hawaii stock), sei whale (Eastern North Pacific stock), and 
sperm whale (CA/OR/WA stock).
    In conclusion, although it is generally unlikely that any whales 
will be struck in a year, based on the information and analysis above, 
NMFS anticipates that no more than three whales could be taken by 
serious injury or mortality over the five-year period of the rule, and 
that those three whales may include no more than two of any of the 
following stocks: Gray whale (Eastern North Pacific stock), fin whale 
(CA/OR/WA stock), humpback whale (Central North Pacific stock); and no 
more than one of any of the following stocks: Blue whale (Eastern North 
Pacific stock), humpback whale (CA/OR/WA, Mexico DPS), and sperm whale 
(Hawaii stock). Accordingly, NMFS has evaluated under the negligible 
impact standard the serious injury or mortality of 0.2 or 0.4 whales 
annually from each of these species or stocks (i.e., 1 or 2 takes, 
respectively, divided by 5 years to get the annual number), along with 
other expected harassment incidental take.
Explosives
    The Navy's model and quantitative analysis process used for the 
HSTT FEIS/OEIS and in the Navy's rulemaking/LOA application to estimate 
potential exposures of marine mammals to explosive stressors is 
detailed in the technical report titled Quantifying Acoustic Impacts on 
Marine Mammals and Sea Turtles: Methods and Analytical Approach for 
Phase III Training and Testing report (U.S. Department of the Navy, 
2018). Specifically, over the course of a year, the Navy's model and 
quantitative analysis process estimates mortality of two short-beaked 
common dolphin and one California sea lion as a result of exposure to 
explosive training and testing activities (please refer to section 6 of 
the Navy's rule making/LOA application). Over the five[hyphen]year 
period of the regulations requested, mortality of 10 marine mammals in 
total (6 short-beaked common dolphins and 4 California sea lions) is 
estimated as a result of exposure to explosive training and testing 
activities. NMFS coordinated with the Navy in the development of their 
take estimates and concurs with the Navy's approach for estimating the 
number of animals from each species that could be affected by mortality 
takes from explosives.

Mitigation Measures

    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'' (``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.
    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 with a `negligible impact' 
finding.'' More recently, expressing similar concerns in a challenge to 
a U.S. Navy Surveillance Towed Array Sensor System Low Frequency Active 
Sonar (SURTASS LFA) incidental take rule (77 FR 50290), 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

[[Page 66947]]

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) and the Navy Atlantic Fleet Testing and Training rule (83 FR 
57076; November 14, 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 U.S. Fish and Wildlife Service's 
implementing regulations for section 101(a)(5) both define ``negligible 
impact'' as ``an impact resulting from the specified activity that 
cannot be reasonably expected to, and is not reasonably likely to, 
adversely affect the species or stock through effects on annual rates 
of recruitment or survival'' (50 CFR 216.103 and 50 CFR 18.27(c)). 
Recruitment (i.e., reproduction) and survival rates are used to 
determine population growth rates \3\ and, therefore are considered in 
evaluating population level impacts.
---------------------------------------------------------------------------

    \3\ 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. [T]he 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.\4\
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    \4\ 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 standard is concerned solely with 
conclusions about the impact of an activity on annual rates of 
recruitment and survival.\5\
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    \5\ 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

[[Page 66948]]

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 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. 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 will be 
carefully considered to determine the types of mitigation that are 
appropriate under the least practicable adverse impact

[[Page 66949]]

standard. We discuss consideration of these factors in greater detail 
below.
    1. Reduction of adverse impacts to marine mammal species or stocks 
and their habitat.\6\ 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.
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    \6\ 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)).

Assessment of Mitigation Measures for HSTT Rule

    NMFS reviewed the Specified Activities and the mitigation measures 
as described in the Navy's rulemaking/LOA application and the HSTT 
FEIS/OEIS to determine if they would result in the least practicable 
adverse effect on marine mammals. NMFS worked with the Navy in the 
development of the Navy's initially proposed measures, which are 
informed by years of implementation and monitoring. A complete 
discussion of the evaluation process used to develop, assess, and 
select mitigation measures, which was coordinated with and informed by 
input from NMFS and included consideration of the measures that were 
added as a result of the settlement agreement (see below), can be found 
in Chapter 5 (Mitigation) and Appendix K (Geographic Mitigation 
Assessment) of the HSTT FEIS/OEIS and is summarized below in this 
section. The process described in Chapter 5 (Mitigation) and Appendix K 
(Geographic Mitigation Assessment) of the HSTT FEIS/OEIS robustly 
supports NMFS' independent evaluation of whether the mitigation 
measures required by this rule meet the least practicable adverse 
impact standard. The Navy is required to implement the mitigation 
measures identified in this rule to avoid or reduce potential impacts 
from acoustic, explosive, and physical disturbance and ship strike 
stressors.
    As a general matter, where an applicant proposes measures that are 
likely to reduce impacts to marine mammals, the fact that they are 
included in the proposal and application indicates that the measures 
are practicable, and it is not necessary for NMFS to conduct a detailed 
analysis of the measures the applicant proposed (rather, they are 
simply included). We note that in their application, the Navy added a 
couple of mitigation measures that were new since the 2013-2018 HSTT 
incidental take regulations: (1) The Santa Barbara Island Mitigation 
Area--to avoid or reduce potential impacts from mid-frequency active 
sonar and explosives on numerous marine mammal species (including blue 
whales and gray whales) within the mitigation area, which contains 
important foraging or migration habitat and overlaps a portion of the 
Channel Islands National Marine Sanctuary, and (2) Blue Whale, Gray 
Whale, and Fin Whale Awareness Notification Message Areas--to further 
help avoid or reduce potential impacts from vessel strikes and training 
and testing activities on blue whales, gray whales, and fin whales 
within the Southern California portion of the Study Area, which 
contains important seasonal foraging or migration habitat for these 
species. However, it is still necessary for NMFS to consider whether 
there are additional practicable measures that could also contribute to 
the reduction of adverse effects on the species or stocks through 
effects on annual rates of recruitment or survival. In the case of the 
Navy's HSTT application, we worked with the Navy

[[Page 66950]]

prior to the publication of the proposed rule and ultimately, the Navy 
agreed to significantly expand geographic mitigation areas adjacent to 
the island of Hawaii to more fully encompass the Alenuihaha Channel 
(important habitat and migration area) and overlap the BIAs of multiple 
species (reproductive area for humpbacks, and overlapping the ranges of 
multiple small resident populations of odontocetes) and to limit 
additional anti-submarine warfare mid-frequency active sonar (ASW) 
source bins (MF4) within those mitigation areas, which is expected to 
further reduce the probability and severity of impacts that would be 
more likely to affect reproduction or survival of individuals or 
adversely affect the stock.
    Of note, following publication of the 2013 HSTT incidental take 
rule, the Navy and NMFS were sued and the parties reached a settlement 
in Conservation Council for Hawaii v. National Marine Fisheries 
Service, 97 F. Supp.3d 1210 (D. Haw. 2015), in which the Navy agreed to 
restrict its activities within specific areas in the HSTT Study Area 
(beyond the areas and restrictions included as mitigation measures in 
the 2013 rule). Additional detail is provided below in the subsection 
entitled Brief Comparison of Settlement Mitigation and Final HSTT 
Mitigation in the Rule.
    In summary (and as described in more detail below in this section), 
the Navy has agreed to procedural mitigation measures that will reduce 
the probability and/or severity of impacts expected to result from 
acute exposure to acoustic sources or explosives, ship strike, and 
impacts to marine mammal habitat. Specifically, the Navy will use a 
combination of delayed starts, powerdowns, and shutdowns to minimize or 
avoid serious injury or mortality, minimize the likelihood or severity 
of PTS or other injury, and reduce instances of TTS or more severe 
behavioral disruption caused by acoustic sources or explosives. The 
Navy also will implement multiple time/area restrictions (several of 
which have been added since the 2013 HSTT MMPA incidental take rule) 
that would reduce take of marine mammals in areas or at times where 
they are known to engage in important behaviors, such as feeding or 
calving, where the disruption of those behaviors would have a higher 
probability of resulting in impacts on reproduction or survival of 
individuals that could lead to population-level impacts.
    Since publication of the proposed rule, NMFS and the Navy have 
agreed to additional mitigation measures that are expected to reduce 
the likelihood and/or severity of adverse impacts on marine species/
stocks and their habitat and are practicable for implementation. Below 
we summarize the added measures and describe the manner in which they 
are expected to reduce the likelihood or severity of adverse impacts on 
marine mammal species or stocks and their habitat. A full description 
of each measure is included in Tables 45-62.
    1. Pre-event in-water explosive event observations--The Navy will 
implement pre-event observation mitigation for all in-water explosive 
event mitigation measures. Additionally, if there are other platforms 
participating in these events and in the vicinity of the detonation 
area, Navy personnel on those platforms will also visually observe this 
area as part of the mitigation team. This added monitoring for a subset 
of activities for which it was not previously required (explosive 
bombs, missiles and rockets, projectiles, torpedoes, and grenades) in 
advance of explosive events increases the likelihood that marine 
mammals will be detected if they are in the mitigation area for that 
event and that, if any animals are detected, explosions will be delayed 
by timely mitigation implementation, thereby further reducing the 
already low likelihood that animals will be injured or killed by the 
blast.
    2. Post-event in-water explosive event observations--The Navy will 
implement post-event observation mitigation for all in-water explosive 
event mitigation measures. Additionally, if there are other platforms 
participating in these events and in the vicinity of the detonation 
area, Navy personnel on those platforms will also visually observe this 
area as part of the mitigation team. This added monitoring for a subset 
of activities for which it was not previously required (explosive 
bombs, missiles and rockets, projectiles, torpedoes, grenades) 
increases the likelihood that any injured marine mammals would be 
detected following an explosive event, which would increase our 
understanding of impacts and could potentially inform mitigation 
changes via the adaptive management provisions.
    3. The San Diego Arc Mitigation Area was the initial mitigation 
area for the proposed rule. For the final rule, the Navy agreed to add 
the San Nicolas Island and Santa Monica/Long Beach Mitigation Areas 
(June 1-October 31), which include all of the relatively small portions 
of the Santa Monica Bay/Long Beach and San Nicolas Island BIAs that 
overlap the HSTT Study Area (55.4 Nmi\2\ or 13.9 percent and 33.6 
Nmi\2\ or 23.5 percent, respectively). The Navy agrees to limit 
explosives during training in the Santa Monica Bay/Long Beach and San 
Nicolas Island Mitigation Areas. This reduction of activities (as 
described here and in the newly expanded measure immediately below, 
i.e., fewer explosives and MF1 sonar) in these areas with higher 
concentrations of blue whales engaged in important feeding behaviors is 
expected to reduce the probability or severity of impacts on blue 
whales that would be more likely to adversely affect the reproduction 
or survival of any individual, which in turn reduces the likelihood 
that any impacts would translate to adverse impacts on the stock.
    4. The Navy agrees to limit surface ship sonar in the Santa Monica/
Long Beach and San Nicolas Island Mitigation Areas. The Navy will not 
exceed 200 hrs of MFAS sensor MF1 from June 1 through October 31 in the 
combined San Diego Arc, San Nicolas Island, and Santa Monica/Long Beach 
Mitigation Areas (manner in which this helps reduce impact to marine 
mammals noted directly above).
    5. In the proposed rule, the Navy included a seasonal restriction 
on the use of hull-mounted active sonar in the 4-Islands Mitigation 
Area, but no limit on explosive use. The Navy has added an all-year 
restriction on the use of explosives in this area. The 4-Islands 
Mitigation Area overlaps with a reproductive BIA for humpback whales, 
as well as BIAs for several small resident populations of multiple 
odontocetes (bottlenose dolphins, main Hawaiian Island false killer 
whales, pantropical spotted dolphins, and spinner dolphins). For 
humpback whales, the reduction of activities in this area with 
individuals that have calves or are potentially breeding is expected to 
reduce the probability or severity of impacts that would be more likely 
to adversely impact reproduction or survival of individuals by directly 
interfering with breeding behaviors or by separating mothers and calves 
at a time with calves are more susceptible to predators. For the 
odontocete stocks with BIAs for small resident populations, we aim to 
avoid overwhelming small populations (which are more susceptible to 
certain population effects, such as Allee effects) with large scale 
impacts, especially when the population is limited to a small area and 
less able to access alternative habitat. Limiting explosive effects in 
these mitigation areas that overlap the BIAs further reduces impacts to 
these stocks, although we note that all four of these odontocete small 
resident populations span multiple islands, which means that

[[Page 66951]]

impacts in any one location are less likely to affect the whole 
population.
    6. The Navy has agreed to issue notification messages to increase 
operator awareness of the presence of marine mammals. The Navy will 
review WhaleWatch, a program coordinated by NMFS' West Coast Region as 
an additional information source to inform the drafting of the annual 
notification messages for blue, fin, and gray whales in SOCAL.The 
information will alert vessels to the possible presence of these stocks 
to maintain safety of navigation and further reduce the potential for a 
vessel strike. Any expanded mechanisms for detecting large whales, 
either directly around a vessel or in the wider area to increase 
vigilance for vessels, further reduce the probability that a whale will 
be struck.
    The Navy assessed the new and/or expanded measures it has agreed to 
(above) in the context of personnel safety, practicality of 
implementation, and their impacts on the Navy's ability to meet their 
Title 10 requirements and found that the measures were supportable. As 
described above, NMFS has independently evaluated all of the measures 
the Navy has committed to (including those above added since the 
proposed rule was published) in the manner described earlier in this 
section (i.e., in consideration of their ability to reduce adverse 
impacts on marine mammal species and stocks and their habitat and their 
practicability for implementation). We have determined that the 
additional measures will further reduce impacts on the affected marine 
mammal species and stocks and their habitat beyond the initial measures 
proposed and, further, be practicable for Navy implementation.
    The Navy also evaluated numerous measures in the HSTT FEIS/OEIS 
that were not included in the Navy's rulemaking/LOA application, and 
NMFS independently reviewed and concurs with Navy's analysis that their 
inclusion was not appropriate under the least practicable adverse 
impact standard based on our assessment. The Navy considered these 
additional potential mitigation measures in two groups. First, Chapter 
5 (Mitigation) of the HSTT FEIS/OEIS, in the Measures Considered but 
Eliminated section, includes an analysis of an array of different types 
of mitigation that have been recommended over the years by NGOs or the 
public, through scoping or public comment on environmental compliance 
documents. Appendix K (Geographic Mitigation Assessment) of the HSTT 
FEIS/OEIS includes an in-depth analysis of time/area restrictions that 
have been recommended over time or previously implemented as a result 
of litigation. As described in Chapter 5 (Mitigation) of the HSTT FEIS/
OEIS, commenters sometimes recommend that the Navy reduce its overall 
amount of training, reduce explosive use, modify its sound sources, 
completely replace live training with computer simulation, or include 
time of day restrictions. Many of these mitigation measures could 
potentially reduce the number of marine mammals taken, via direct 
reduction of the activities or amount of sound energy put in the water. 
However, as the Navy has described in Chapter 5 (Mitigation) of the 
HSTT FEIS/OEIS, the Navy needs to train and test in the conditions in 
which it fights--and these types of modifications fundamentally change 
the activity in a manner that would not support the purpose and need 
for the training and testing (i.e., are entirely impracticable) and 
therefore are not considered further. NMFS finds the Navy's explanation 
for why adoption of these recommendations would unacceptably undermine 
the purpose of the testing and training persuasive. After independent 
review, NMFS finds Navy's judgment on the impacts of potential 
mitigation measures to personnel safety, practicality of 
implementation, and the undermining of the effectiveness of training 
and testing persuasive, and for these reasons, NMFS finds that these 
measures do not meet the least practicable adverse impact standard 
because they are not practicable.
    Second in Chapter 5 (Mitigation) of the HSTT FEIS/OEIS, the Navy 
evaluated additional potential procedural mitigation measures, 
including increased mitigation zones, ramp-up measures, additional 
passive acoustic and visual monitoring, and decreased vessel speeds. 
Some of these measures have the potential to incrementally reduce take 
to some degree in certain circumstances, though the degree to which 
this would occur is typically low or uncertain. However, as described 
in the Navy's analysis, the measures would have significant direct 
negative effects on mission effectiveness and are considered 
impracticable (see Chapter 5 Mitigation of HSTT FEIS/OEIS). NMFS 
independently reviewed the Navy's evaluation and concurred with this 
assessment, which supports NMFS' findings that the impracticability of 
this additional mitigation would greatly outweigh any potential minor 
reduction in marine mammal impacts that might result; therefore, these 
additional mitigation measures are not required under the least 
practicable adverse impact standard.
    Last, Appendix K (Geographic Mitigation Assessment) of the HSTT 
FEIS/OEIS describes a comprehensive method for analyzing potential 
geographic mitigation that includes consideration of both a biological 
assessment of how the potential time/area limitation would benefit the 
species or stock and its habitat (e.g., is a key area of biological 
importance or would result in avoidance or reduction of impacts) in the 
context of the stressors of concern in the specific area and an 
operational assessment of the practicability of implementation (e.g., 
including an assessment of the specific importance of that area for 
training, considering proximity to training ranges and emergency 
landing fields and other issues). The analysis analyzes an extensive 
list of areas, including areas in which certain Navy activities were 
limited under the terms of the 2015 HSTT settlement agreement, areas 
identified by the California Coastal Commission, and areas suggested 
during scoping. For the areas that were agreed to under the settlement 
agreement, the Navy notes two important facts that NMFS generally 
concurs with: (1) The measures were derived pursuant to negotiations 
with plaintiffs and were specifically not evaluated or selected based 
on the examination of the best available science that NMFS typically 
applies to a mitigation assessment and (2) the Navy's adoption of 
restrictions on its activities as part of a relatively short-term 
settlement does not mean that those restrictions are practicable to 
implement over the longer term.
    The Navy proposed (and NMFS has incorporated into this rule) 
several time/area mitigations that were not included in the 2013-2018 
HSTT MMPA regulations (as described above). For the areas that are not 
included in these regulations, though, the analysis in the HSTT FEIS/
OEIS (Chapter 5 and Appendix K) shows that on balance, the mitigation 
was not warranted because the anticipated reduction of adverse impacts 
on marine mammal species or stocks and their habitat was not sufficient 
to offset the impracticability of implementation (in some cases 
potential benefits to marine mammals were limited to non-existent, in 
others the consequences on mission effectiveness were too great). We 
note that in regard to the protection of marine mammal habitat, habitat 
value is informed by marine mammal presence and use and, in some cases, 
there may be overlap in measures that minimize impacts to the species 
or stock directly and measures that minimize impacts on

[[Page 66952]]

habitat. In this rule, we have identified time-area mitigations based 
on a combination of factors that include higher densities and 
observations of specific important behaviors of marine mammals 
themselves, but also that clearly reflect preferred habitat (e.g., blue 
whale feeding areas in SOCAL, and in-shore small resident populations 
of odontocetes around Hawaii). In addition to being delineated based on 
physical features that drive habitat function (e.g., bathymetric 
features, among others for some BIAs), the high densities and 
concentration of certain important behaviors (e.g., feeding) in these 
particular areas clearly indicate the presence of preferred habitat.
    Overall, NMFS has independently reviewed the Navy's mitigation 
analysis Chapter 5 (Mitigation) and Appendix K (Geographic Mitigation 
Assessment) of the HSTT FEIS/OEIS as referenced above), which considers 
the same factors that NMFS considers to satisfy the least practical 
adverse impact standard, and concurs with the conclusions. Therefore, 
NMFS is not including the additional measures discussed in the HSTT 
FEIS/OEIS in these regulations, other than the new measures that were 
discussed in the proposed rule and those agreed upon after publication 
of the proposed rule, as described above. Below, we list and describe 
the mitigation measures (organized into procedural measures and 
mitigation areas) that NMFS has determined will ensure the least 
practicable adverse impact on all affected species and stocks and their 
habitat, including the specific considerations for military readiness 
activities. However, first, in the section immediately below, we 
provide a brief summary of the ways in which the mitigation included in 
this rule compares to the mitigation the Navy implemented during the 
settlement agreement.

Brief Comparison of 2015 Settlement Mitigation and Final HSTT 
Mitigation in the Rule

    As noted above, following publication of the 2013 HSTT MMPA 
incidental take rule, the Navy and NMFS were sued and the parties 
reached a settlement in 2015 under which the Navy agreed to restrict 
its activities within specific areas in the HSTT Study Area (beyond the 
areas and restrictions included in the 2013 rule). While we have 
described above the analysis that supports the selection of mitigation 
measures included in the final rule (referencing the associated Navy 
documents, where appropriate), because the Navy has been implementing 
the settlement agreement measures since 2015, we provide here a summary 
description of the differences and additional analysis.
    First, we note broadly that the provisional restrictions on 
activities within the HSTT Study Area were derived pursuant to 
negotiations with the plaintiffs as part of the lawsuit and 
specifically were not evaluated or selected based on the best available 
science as would occur through the MMPA rulemaking process or through 
related analyses conducted under the National Environmental Policy Act 
(NEPA) or the ESA. The agreement did not constitute a concession by the 
Navy as to the impacts of Navy activities on marine mammals or any 
other marine species, the extent to which the measures would reduce 
impacts, or the practicability of the measures. The Navy's adoption of 
restrictions on its HSTT testing and training activities as part of the 
relatively short-term settlement agreement therefore did not mean that 
those restrictions were supported by the best available science, likely 
to reduce impacts on marine mammals species or stocks and their 
habitat, or practicable to implement from a military readiness 
standpoint over the longer term in the HSTT Study Area. Accordingly, as 
required by statute, NMFS analyzed the Navy's activities as set forth 
in its application and including impacts, proposed mitigation, and 
additional potential mitigation (including the settlement agreement 
measures) pursuant to the ``least practicable adverse impact'' standard 
to determine the appropriate mitigation to include in these 
regulations. Some of the measures that were included in the 2015 
settlement agreement are included in the final rule, while some are 
not.
    As characterized elsewhere in the rule, we look here at the 
differences in both procedural mitigation measures and mitigation 
areas. The 2015 settlement agreement included two procedural 
mitigations (one of which was a group of related reporting measures). 
Regarding one of the measures, the 2015 settlement agreement indicated 
that ``Navy surface vessels operating within the HSTT shall avoid 
approaching marine mammals head-on and shall maneuver to maintain a 500 
yard (457 meter) mitigation zone for observed whales and a 200 yard 
(183 meter) mitigation zone for all other observed marine mammals 
(except bow riding dolphins), providing it is safe to do so.'' This 
measure is fully included in this final rule. Regarding the other 
measure, the settlement agreement included several related reporting 
requirements for NMFS to implement in the event the discovery of an 
injured or dead marine mammal triggered certain Navy reporting 
requirements included in the 2013 rule. These reporting requirements 
are not included in this rule both because it is not the role of 
101(a)(5)(A) regulations to require reporting and notifications by NMFS 
to others (where appropriate notice and opportunity for public 
involvement is already provided for under the statute) and this 
reporting by NMFS did not further the conservation of marine mammals. 
Last, these settlement agreement reporting measures highlighted 
inconsistencies between some of the measures required under the 2013 
regulations and those inconsistencies have been resolved; the 2018 LOAs 
include updated reporting requirements.
    NMFS' and the Navy's analysis of mitigation areas is described in 
the subsections above and the description of areas included in the 
final rule are described in the subsection below. In order to assist 
the reader in understanding the differences in mitigation areas between 
the terms of the 2015 settlement agreement (as a result of the ruling 
in Conservation Council for Hawaii v. National Marine Fisheries 
Service, 97 F. Supp.3d 1210 (D. Haw. 2015)) and this final rule, we 
offer the following:

    <bullet> Figures 1, 2, 3, and 4 below depict the settlement 
mitigation areas and the HSTT Mitigation Areas for Hawaii and SOCAL.
    <bullet> Table 44 below compares the mitigation requirements 
from the 2015 settlement agreement areas to the mitigation 
requirements for the areas specified in this final rule (noting also 
the species for which impacts will be reduced).
    <bullet> Table K.2-2 of Appendix K in the HSTT FEIS/OEIS 
includes a comparison of the settlement agreement areas to 
mitigation areas for this rulemaking period by species and BIAs.
    <bullet> NMFS' CetSound website includes an interactive map 
depicting the BIAs for all species and stocks (there are 12 
overlapping BIAs in the main Hawaiian Islands, making it difficult 
to present them effectively in a static map). See https://cetsound.noaa.gov/biologically-important-area-map.
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 Table 44--Comparison of Mitigation Areas in Effect 2015-2018 Under the
  2015 Settlement Agreement to Mitigation Areas Implemented Under 2018
                               Final Rule
------------------------------------------------------------------------
Litigation settlement  (2015-December   HSTT final MMPA incidental take
                2018)                      rule  (December 2018-2023)
------------------------------------------------------------------------
Hawaii                                 Hawaii
    <bullet> Area 1-A Hawaii Island    <bullet> Hawaii Island Mitigation
     (North, South, East) (year-        Area (year-round). Incorporates
     round). (a) Prohibit the use of    parts of settlement measures 1-A
     MFAS for training and testing      through 1-E and 2-A through 2-E.
     activities during both MTEs and    Navy will minimize the use of
     unit-level training; and (b)       MFAS (MF1 and MF4) and will not
     prohibit the use of in-water       use explosives during testing
     explosives for training and        and training. Reduces impacts on
     testing activities. Reduces        ESA-listed false killer whales
     impacts to false killer whales,    and monk seals, two species of
     pygmy killer whales, short-        beaked whales, humpback whales,
     finned pilot whales, bottlenose    and other species.
     dolphins, spinner dolphins,
     Cuvier's beaked whales, and
     Blainville's beaked whales
    <bullet> Area 1-B Hawaii Island    <bullet> 4-Islands Region
     (Northwest) (year-round). Limit    Mitigation Area (November 1-
     the use of MFAS for training and   April 15 for active sonar, year-
     testing activities during MTEs     round for explosives).
     to one Rim of the Pacific in       Incorporates parts of settlement
     2016, one Rim of the Pacific in    Areas 1-A, 1-B, 1-C, 1-D, 1-E, 2-
     2018, three Undersea Warfare       A, 2-B, and 2-C and humpback
     Exercises per calendar year, and   reporting area. Navy will not
     one Independent Deployer           use MFAS (MF1) or explosives in
     Certification Exercise per         this mitigation area during
     calendar year. Reduces impacts     training and testing. Reduces
     to humpback whales, false killer   impacts to humpback whales, ESA-
     whales, short-finned pilot         listed false killer whales and
     whales, melon-headed whales,       monk seals, and some dolphin
     bottlenose dolphins, spinner       species.
     dolphins, Cuvier's beaked         <bullet> Humpback Whale Special
     whales, and Blainville's beaked    Reporting Areas (December 15-
     whales                             April 15). Incorporates parts of
                                        settlement areas 1-B, 1-C, 1-D,
                                        2-A, 2-B, and 2-D, humpback
                                        special reporting area and
                                        humpback cautionary area. Navy
                                        will report the hours of MF1
                                        used in these areas in training
                                        and testing activity reports.
                                       <bullet> Humpback Whale Awareness
                                        Notification Message Area
                                        (November-April). Navy will
                                        issue a seasonal awareness
                                        notification message to alert
                                        ships and aircraft operating in
                                        the area to the possible
                                        presence of concentrations of
                                        large whales, including humpback
                                        whales.
    <bullet> Area 1-C Hawaii Island    .................................
     (West) (year-round). (a) Limit
     the use of MFAS for training and
     testing activities during MTEs
     to one Rim of the Pacific in
     2016, one Rim of the Pacific in
     2018, three Undersea Warfare
     Exercises per calendar year, and
     one Independent Deployer
     Certification Exercise per
     calendar year; (b) prohibit the
     use of MFAS for training and
     testing activities during unit-
     level training (excluding unit-
     level training conducted by
     participants in an ongoing MTE;
     and (c) prohibit the use of in-
     water explosives for training
     and testing activities. Reduces
     impacts to humpback whales,
     false killer whales, dwarf sperm
     whales, pygmy killer whales,
     short-finned pilot whales,
     bottlenose dolphins, spotted
     dolphins, spinner dolphins,
     rough toothed dolphins, Cuvier's
     beaked whales, and Blainville's
     beaked whales
    <bullet> Area 1-D Hawaii Island    .................................
     (Southwest) (year-round). (a)
     Limit the use of MFAS for
     training and testing activities
     during MTEs to one Rim of the
     Pacific in 2016, one Rim of the
     Pacific in 2018, three Undersea
     Warfare Exercises per calendar
     year, one Independent Deployer
     Certification Exercise per
     calendar year, and one
     Sustainment Exercise per
     calendar year; (b) prohibit the
     use of MFAS for training and
     testing activities during unit-
     level training (excluding unit-
     level training conducted by
     participants in ongoing MTEs );
     and (c) prohibit the use of in-
     water explosives for training
     and testing activities. Reduces
     impacts to dwarf sperm whales,
     pygmy killer whales, short-
     finned pilot whales, bottlenose
     dolphins, spotted dolphins,
     spinner dolphins, rough-toothed
     dolphins, Cuvier's beaked
     whales, and Blainville's beaked
     whales
    <bullet> Area 1-E and 2-E Hawaii   .................................
     Island (nearshore Northwest)
     (year-round). Require that all
     surface vessels use extreme
     caution and proceed at safe
     speed so they can take proper
     and effective action to avoid a
     collision with any sighted
     object or disturbance, and can
     be stopped within a distance
     appropriate to the prevailing
     circumstances and conditions.
     Reduces impacts to dwarf sperm
     whales, false killer whales,
     pygmy killer whales, melon-
     headed whales, bottlenose
     dolphins, spotted dolphins,
     spinner dolphins, rough-toothed
     dolphins, and Blainville's
     beaked whales

[[Page 66956]]

 
    <bullet> Area 2-A (Southeast       .................................
     Oahu, Southwest Molokai, Penguin
     Bank) (year-round). (a) Prohibit
     the use of MFAS for training and
     testing activities during MTEs;
     (b) prohibit the use of in-water
     explosives for training and
     testing activities; and (c)
     require that all surface vessels
     use extreme caution and proceed
     at safe speed so they can take
     proper and effective action to
     avoid a collision with any
     sighted object or disturbance,
     and can be stopped within a
     distance appropriate to the
     prevailing circumstances and
     conditions. Reduces impacts to
     humpback whales, false killer
     whales, bottlenose dolphins, and
     spinner dolphins
    <bullet> Area 2-B (South Molokai,  .................................
     East Maui, Penguin Bank) (year-
     round). (a) Prohibit the use of
     in-water explosives for training
     and testing activities; and (b)
     require that all surface vessels
     use extreme caution and proceed
     at safe speed so they can take
     proper and effective action to
     avoid a collision with any
     sighted object or disturbance,
     and can be stopped within a
     distance appropriate to the
     prevailing circumstances and
     conditions. Reduces impacts to
     humpback whales, bottlenose
     dolphins, spotted dolphins, and
     spinner dolphins
    <bullet> Area 2-C (North Molokai,  .................................
     North Maui) (year-round). (a)
     Prohibit the use of MFAS for
     training and testing activities
     during MTEs; (b) implement a
     Protective Measure Assessment
     Protocol measure advising
     Commanding Officers that the
     area is false killer whale
     habitat and that they should
     avoid using MFAS during unit-
     level training within the area
     whenever practicable; and (c)
     prohibit the use of in-water
     explosives for training and
     testing activities (within the
     overlap of Area 2-B and Area 2-
     C, the restrictions imposed in
     Area 2-B and Area 2-C both
     apply). Reduces impacts to false
     killer whales, bottlenose
     dolphins, and spinner dolphins
    <bullet> Area 2-D (Southeast       .................................
     Oahu, Northwest Molokai) (year-
     round). Prohibit the use of in-
     water explosives for training
     and testing activities. Reduces
     impacts to false killer whales,
     bottlenose dolphins, and spinner
     dolphins
------------------------------------------------------------------------
Southern California                    Southern California
    <bullet> Area 3-A (San Diego Arc,  <bullet> San Diego Arc, San
     coastal) (June 1-October 31).      Nicolas Island, and Santa Monica/
     (a) Prohibit the use of MFAS for   Long Beach Mitigation Areas
     training and testing activities    (June 1-October 31).
     during MTEs and unit-level         Incorporates parts of settlement
     training; and (b) require that     areas 3-A, 3-B, 3-C, 4-A, 4-B, 4-
     all surface vessels use extreme    C, and 4-D. Navy will minimize
     caution and proceed at safe        the use of MFAS (MF1) within the
     speed so they can take proper      three Mitigation Areas during
     and effective action to avoid a    training and testing. Within the
     collision with any sighted         San Diego Arc Mitigation Area,
     object or disturbance, and can     Navy will not use explosives
     be stopped within a distance       during large-caliber gunnery,
     appropriate to the prevailing      torpedo, bombing, and missile
     circumstances and conditions.      activities during testing and
     Reduces impacts to blue and gray   training. Within the San Nicolas
     whales                             Island Mitigation Area Navy will
                                        not use explosives during mine
                                        warfare, large-caliber gunnery,
                                        torpedo, bombing and missile
                                        activities during training.
                                        Within the Santa Monica/Long
                                        Beach Mitigation Area, Navy will
                                        not use explosives during mine
                                        warfare, large-caliber gunnery,
                                        torpedo, bombing, and missile
                                        (including 2.75'' rockets)
                                        activities during training and
                                        testing. Reduces impacts
                                        primarily to blue whales, but
                                        also gray and fin whales.
                                       <bullet> Santa Barbara Island
                                        Mitigation Area (year-round).
                                        Incorporates parts of settlement
                                        areas 4A, Channel Island NMS.
                                        Navy will not use MFAS (MF1) and
                                        explosives in small-, medium-,
                                        and large-caliber gunnery,
                                        torpedo, bombing, and missile
                                        activities during unit-level
                                        training or MTEs. Reduces
                                        impacts to numerous marine
                                        mammal species that use the
                                        Channel Islands NMS and
                                        partially overlap areas for blue
                                        whales and gray whales.
                                       <bullet> Blue Whale (June-
                                        October), Gray Whale (November-
                                        March), and Fin Whale (November-
                                        May) Awareness Notification
                                        Message Areas. Navy will issue a
                                        seasonal awareness notification
                                        message to alert ships and
                                        aircraft operating in the area
                                        to the possible presence of
                                        concentrations of large whales,
                                        particularly blue, gray, and fin
                                        whales.

[[Page 66957]]

 
    <bullet> Area 3-B (San Diego Arc,  .................................
     coastal) (June 1-October 31).
     (a) Prohibit the use of MFAS for
     training and testing activities
     during MTEs and unit-level
     training, except for system
     checks; (b) implement a seasonal
     Protective Measure Assessment
     Protocol measure advising
     Commanding Officers that the
     area is blue whale habitat and
     that they should avoid
     conducting system checks within
     the area whenever practicable;
     and (c) require that all surface
     vessels use extreme caution and
     proceed at safe speed so they
     can take proper and effective
     action to avoid a collision with
     any sighted object or
     disturbance, and can be stopped
     within a distance appropriate to
     the prevailing circumstances and
     conditions. Reduces impacts to
     blue and gray whales
    <bullet> Area 3-C (Santa Monica    .................................
     Bay to Long Beach, coastal)
     (November 1-May 20). Require
     that all surface vessels use
     extreme caution and proceed at
     safe speed so they can take
     proper and effective action to
     avoid a collision with any
     sighted object or disturbance,
     and can be stopped within a
     distance appropriate to the
     prevailing circumstances and
     conditions. Reduces impacts to
     blue and gray whales
    <bullet> Area 4-A (East of San     .................................
     Nicholas Island) (year-round).
     (a) Prohibit the use of MFAS for
     training and testing activities
     during MTEs and unit-level
     training; and (b) prohibit the
     use of in-water explosives for
     training and testing activities.
     Reduces impacts to blue and gray
     whales
    <bullet> Area 4-B (east of Santa   .................................
     Catalina Island) (year-round).
     Prohibit the use of MFAS for
     training and testing activities
     during MTEs and unit-level
     training. Reduces impacts to
     gray whales
    <bullet> Area 4-C (Tanner-Cortes   .................................
     Bank) (June 1-October 31).
     Require that all surface vessels
     use extreme caution and proceed
     at safe speed so they can take
     proper and effective action to
     avoid a collision with any
     sighted object or disturbance,
     and can be stopped within a
     distance appropriate to the
     prevailing circumstances and
     conditions. Reduces impacts to
     blue and gray whales
    <bullet> Area 4-D (south of 4-A)   .................................
     (year-round). Require all
     surface vessels to use extreme
     caution and proceed at a safe
     speed so they can take proper
     and effective action to avoid a
     collision with any sighted
     object or disturbance, and can
     be stopped within a distance
     appropriate to the prevailing
     circumstances and conditions.
     Reduces impacts to gray whales
------------------------------------------------------------------------

    As described above, NMFS analyzed the Navy's activities as set 
forth in its application, the impacts of those activities, the 
proposed mitigation, and potential additional mitigation (including 
the 2015 settlement agreement measures) pursuant to the ``least 
practicable adverse impact'' standard to determine the appropriate 
mitigation to include in these regulations. Some of the measures 
that were included in the 2015 settlement agreement are included in 
this final rule (for example, the vast majority of the area in 
Hawaii included in the mitigation for the settlement agreement is 
included in Mitigation Areas in this rule), while some are not (for 
example, because of the instrumented ranges and specific training 
needs in SOCAL, less of the area covered in the settlement agreement 
is included as Mitigation Areas in this rule). As noted previously, 
Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS 
includes a detailed analysis of all of the potential mitigation 
areas and associated measures (including the settlement measures 
addressed in this section), in the context of both reduction of 
marine mammal impacts and practicability. NMFS has independently 
reviewed Appendix K (Geographic Mitigation Assessment), determined 
that the analysis reflects the best available science, and used the 
information to support our findings outlined in this Mitigation 
Measures section. A summary of the rationale for not adopting the 
relatively small subset of remaining 2015 settlement agreement 
measures that were not carried forward follows.
    In Hawaii, about 85 percent of the area that was covered by 2015 
settlement areas is covered by mitigation areas in this final rule 
(see Figures 1 and 2 above). The protected area around the island of 
Hawaii is the same in this rule as it was in the 2015 settlement 
agreement (Hawaii Mitigation Area), with the difference being that 
the settlement agreement included mitigation on Penguin Bank and in 
a couple of areas north of Molokai and Maui that are not included in 
the 4-Islands Mitigation Area in this final rule. As explained in 
more detail in the full analysis in Section 3 of Appendix K of the 
HSTT FEIS/OEIS, Penguin Bank offers critical shallow and constrained 
conditions for Navy training (especially submarines) that are not 
available anywhere else in Hawaii. The areas north of Molokai and 
Maui that are not included in the current 4-Islands Mitigation Area 
are similarly critical for certain exercises that specifically 
include torpedo exercises deliberately conducted in this area north 
of the islands to avoid the other suitable training areas between 
the four islands where humpback whale density is higher. The 2015 
settlement agreement mitigation restricted all MFAS and explosive 
use on Penguin Bank (area 2-A), however, as the Navy explains, this 
MFAS restriction is impracticable in that it would have unacceptable 
impacts on their training and testing capabilities. In addition, the 
Navy does not typically use explosives in this area. For the 
settlement areas north of Molokai and Maui that are not covered in 
the rule (area 2-B and part of area 2-C), the settlement agreement 
restricted explosive use but did not restrict MFAS in the 2-B area. 
Explosive use in these areas is also already rare, but for the 
reasons described in Appendix K,

[[Page 66958]]

restricting MFAS use is impracticable and would have unacceptable 
impacts on training and testing. We also note that while it is not 
practicable to restrict MFAS use on Penguin Bank, MFAS use is 
relatively low and we have identified it as a special reporting area 
for which the Navy will report the MFAS use in that area to inform 
adaptive management discussions in the future. Additionally, some of 
the areas that the 2015 settlement agreement identified included 
language regarding extra vigilance intended to avoid vessel strikes. 
Neither NMFS nor the Navy thought that inclusion of this term as 
written would necessarily reduce the probability of a vessel strike, 
so instead we have included the Humpback Whale Awareness 
Notification provision, which sends out a message to all Navy 
vessels in Hawaii during the time that humpback whales are present. 
Last we note that the 2015 settlement mitigation areas with MFAS 
restrictions sometimes excluded all MFAS, while sometimes they 
limited the number of MTEs that could occur (with no limit on any 
particular type of sonar, meaning that hull-mounted surface ship 
sonar could be operated), whereas the sonar restrictions in this 
final rule limit the use of surface ship hull-mounted sonar, which 
is the source that results in the vast majority of incidental takes.
    For SOCAL, the 2015 settlement areas had four primary 
objectives: Reducing impacts in blue whale feeding areas, reducing 
the likelihood of large whale vessel strikes, minimizing incidental 
take of gray whales, and minimizing incidental take of beaked whales 
in areas that the plaintiffs argued were specifically important to 
beaked whales. As noted previously, of the four blue whale feeding 
areas in SOCAL, the Navy mitigation areas in this rule fully cover 
three of them (those associated with settlement areas 3-A, 3-B, 4-A, 
and 4-B in the 2015 settlement agreement) and limit surface ship 
hull-mounted MFAS and explosive use. In fact, we included 
protections for the southern end of a blue whale feeding BIA (Santa 
Monica/Long Beach area), by limiting hull-mounted MFAS and 
explosives that were not included in the 2015 settlement areas. The 
fourth blue whale feeding BIA, Tanner-Cortes Banks, provides unique 
and irreplaceable shallow-water conditions that are critical for 
shallow-water training and testing (especially for submarines) and 
that are not available elsewhere in SOCAL, along with a shallow-
water minefield training range. Notably, in a satellite tracking 
study of blue whales in Southern California from 2014 to 2017, 
Tanner-Cortes Banks was only transited minimally by individual blue 
whales (Mate et al., 2018). Limiting activities in this area would 
inhibit the Navy's ability to successfully test and train and is 
impracticable. In fact, the 2015 settlement area at Tanner-Cortes 
Banks did not limit MFAS or explosive use. Rather, Tanner-Cortes 
Banks (area 4-C), settlement area 4-D, and the large settlement area 
close to shore (area 3-C) each only had one associated protective 
measure, which was language regarding extra vigilance intended to 
avoid vessel strikes. However, neither NMFS nor the Navy thought 
that inclusion of this term as written would necessarily reduce the 
probability of a vessel strike, so instead we have included the Blue 
Whale, Gray Whale, and Fin Whale Awareness Notification Area, which 
sends out a message to all Navy vessels in SOCAL during the time 
these large whales are present and will more effectively help to 
reduce the probability of ship strike.
    The remaining areas covered by 2015 settlement mitigation areas 
that are not covered by mitigation areas in this final rule (area 4-
B and the outer edges of area 4-A, which does not align exactly with 
the blue whale BIA like the current Navy mitigation area does) were 
intended to reduce impacts on gray whales and to provide some sort 
of protection for beaked whales. However, NMFS and the Navy disagree 
that the remaining 2015 settlement areas provide the protection the 
plaintiffs assert. As noted earlier, gray whales migrate primarily 
through a 5 to 10 km corridor along the West Coast, with some 
individuals occasionally ranging offshore (noting that mother/calf 
pairs always stay very close to shore), which resulted in the BIA 
recognizing a 47-km buffer beyond the 5 to 10 km main migration 
corridor, but also expanding the BIA further offshore in order to 
encompass the Channel Islands, where some individuals also sometimes 
range further. Prohibiting activities outside of the main migration 
corridor in an area where gray whales may be present only 
occasionally is not expected to meaningfully reduce effects, 
especially if the mitigation area is small compared to the much 
larger buffer area and the same amount of activities occur outside 
of the mitigation area, but still in the larger area that gray 
whales occupy. Regarding beaked whales, the plaintiffs in the 
Conservation Council for Hawaii case indicated that settlement area 
4-B would provide important habitat for beaked whales based on 
tagging data from two whales in 2014. However, while beaked whales 
are present in the area, tagging data through 2018 (for 27 Cuvier's 
beaked whales) shows that these whales have site fidelity to the 
SOAR Range and typically do not move toward the 2015 settlement 
areas when they do leave SOAR. In other words, since the 2015 
settlement area is not an area of known particular importance for 
these whales, protecting it would not be expected to reduce impacts. 
Appendix K of the HSTT FEIS/OEIS explains in detail why additional 
limitations in this area would inhibit training and testing and 
thereby be impracticable, and the Comments and Responses section of 
this rule addresses these recommendations specifically. In summary, 
the mitigation areas identified in this rule address the valid 
concerns that were targeted through the 2015 settlement agreement, 
but areas that were either impracticable to continue to implement or 
do not provide a reduction in impacts on marine mammals were not 
carried forward.
    The final Procedural Mitigation measures and Mitigation Area 
measures are described in the sections below.

Final Procedural Mitigation

    Procedural mitigation is mitigation that the Navy will implement 
whenever and wherever an applicable training or testing activity 
takes place within the HSTT Study Area. The Navy customizes 
procedural mitigation for each applicable activity category or 
stressor. Procedural mitigation generally involves: (1) The use of 
one or more trained Lookouts to diligently observe for specific 
biological resources (including marine mammals) within a mitigation 
zone, (2) requirements for Lookouts to immediately communicate 
sightings of specific biological resources to the appropriate watch 
station for information dissemination, and (3) requirements for the 
watch station to implement mitigation (e.g., halt an activity) until 
certain recommencement conditions have been met. The first 
procedural mitigation (Table 45) is designed to aid Lookouts and 
other applicable personnel with their observation, environmental 
compliance, and reporting responsibilities. The remainder of the 
procedural mitigation measures (Tables 45 through Tables 64) are 
organized by stressor type and activity category and includes 
acoustic stressors (i.e., active sonar, air guns, pile driving, 
weapons firing noise), explosive stressors (i.e., sonobuoys, 
torpedoes, medium-caliber and large-caliber projectiles, missiles 
and rockets, bombs, sinking exercises, mines, underwater demolition 
multiple charge mat weave and obstacles loading, anti-swimmer 
grenades), and physical disturbance and strike stressors (i.e., 
vessel movement, towed in-water devices, small-, medium-, and large-
caliber non-explosive practice munitions, non-explosive missiles and 
rockets, non-explosive bombs and mine shapes).

Table 45-Procedural Mitigation for Environmental Awareness and Education
------------------------------------------------------------------------
                    Procedural Mitigation Description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> All training and testing activities, as applicable.
Mitigation Requirements:
    <bullet> Appropriate Navy personnel (including civilian personnel)
     involved in mitigation and training or testing activity reporting
     under the specific activities must complete one or more modules of
     the U.S. Navy Afloat Environmental Compliance Training Series, as
     identified in their career path training plan. Modules include:

[[Page 66959]]

 
        --Introduction to the U.S. Navy Afloat Environmental Compliance
         Training Series. The introductory module provides information
         on environmental laws (e.g., ESA, MMPA) and the corresponding
         responsibilities that are relevant to Navy training and testing
         activities. The material explains why environmental compliance
         is important in supporting the Navy's commitment to
         environmental stewardship.
        --Marine Species Awareness Training. All bridge watch personnel,
         Commanding Officers, Executive Officers, maritime patrol
         aircraft aircrews, anti[hyphen]submarine warfare and mine
         warfare rotary-wing aircrews, Lookouts, and equivalent civilian
         personnel must successfully complete the Marine Species
         Awareness Training prior to standing watch or serving as a
         Lookout. The Marine Species Awareness Training provides
         information on sighting cues, visual observation tools and
         techniques, and sighting notification procedures. Navy
         biologists developed Marine Species Awareness Training to
         improve the effectiveness of visual observations for biological
         resources, focusing on marine mammals and sea turtles, and
         including floating vegetation, jellyfish aggregations, and
         flocks of seabirds.
        --U.S. Navy Protective Measures Assessment Protocol. This module
         provides the necessary instruction for accessing mitigation
         requirements during the event planning phase using the
         Protective Measures Assessment Protocol software tool.
        --U.S. Navy Sonar Positional Reporting System and Marine Mammal
         Incident Reporting. This module provides instruction on the
         procedures and activity reporting requirements for the Sonar
         Positional Reporting System and marine mammal incident
         reporting.
------------------------------------------------------------------------

Procedural Mitigation for Acoustic Stressors

    Mitigation measures for acoustic stressors are provided in 
Tables 46 through 49.

Procedural Mitigation for Active Sonar

    Procedural mitigation for active sonar is described in Table 46 
below.

            Table 46--Procedural Mitigation for Active Sonar
------------------------------------------------------------------------
                    Procedural Mitigation Description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Low-frequency active sonar, mid-frequency active sonar,
     high-frequency active sonar.
        --For vessel-based activities, mitigation applies only to
         sources that are positively controlled and deployed from manned
         surface vessels (e.g., sonar sources towed from manned surface
         platforms).
        --For aircraft-based activities, mitigation applies only to
         sources that are positively controlled and deployed from manned
         aircraft that do not operate at high altitudes (e.g., rotary-
         wing aircraft). Mitigation does not apply to active sonar
         sources deployed from unmanned aircraft or aircraft operating
         at high altitudes (e.g., maritime patrol aircraft).
Number of Lookouts and Observation Platform:
    <bullet> Hull-mounted sources:
        --1 Lookout: Platforms with space or manning restrictions while
         underway (at the forward part of a small boat or ship) and
         platforms using active sonar while moored or at anchor
         (including pierside).
        --2 Lookouts: Platforms without space or manning restrictions
         while underway (at the forward part of the ship).
    <bullet> Sources that are not hull-mounted:
        --1 Lookout on the ship or aircraft conducting the activity.
Mitigation Requirements:
    <bullet> Mitigation zones:
        --During the activity, at 1,000 yd Navy personnel must power
         down 6 dB, at 500 yd, Navy personnel must power down an
         additional 4 dB (for a total of 10 dB), and at 200 yd Navy
         personnel must shut down for low-frequency active sonar >=200
         decibels (dB) and hull-mounted mid-frequency active sonar.
        --200 yd shut down for low-frequency active sonar <200 dB, mid-
         frequency active sonar sources that are not hull-mounted, and
         high-frequency active sonar.
    <bullet> Prior to the initial start of the activity (e.g., when
     maneuvering on station):
        --Observe the mitigation zone for floating vegetation; if
         floating vegetation is observed, relocate or delay the start
         until the mitigation zone is clear.
        --Observe the mitigation zone for marine mammals; if marine
         mammals are observed, relocate or delay the start of active
         sonar transmission.
    <bullet> During the activity:
        --Low-frequency active sonar >=200 decibels (dB) and hull-
         mounted mid-frequency active sonar: Navy personnel must observe
         the mitigation zone for marine mammals; power down active sonar
         transmission by 6 dB if marine mammals are observed within
         1,000 yd of the sonar source; power down an additional 4 dB
         (for a total of 10 dB total) within 500 yd; cease transmission
         within 200 yd.
        --Low-frequency active sonar <200 dB, mid-frequency active sonar
         sources that are not hull-mounted, and high-frequency active
         sonar: Observe the mitigation zone for marine mammals; cease
         active sonar transmission if marine mammals are observed within
         200 yd of the sonar source.
    <bullet> Commencement/recommencement conditions after a marine
     mammal sighting before or during the activity:
        --Navy personnel must allow a sighted marine mammal to leave the
         mitigation zone prior to the initial start of the activity (by
         delaying the start) or during the activity (by not recommencing
         or powering up active sonar transmission) until one of the
         following conditions has been met: (1) The animal is observed
         exiting the mitigation zone; (2) the animal is thought to have
         exited the mitigation zone based on a determination of its
         course, speed, and movement relative to the sonar source; (3)
         the mitigation zone has been clear from any additional
         sightings for 10 min. for aircraft-deployed sonar sources or 30
         min. for vessel-deployed sonar sources; (4) for mobile
         activities, the active sonar source has transited a distance
         equal to double that of the mitigation zone size beyond the
         location of the last sighting; or (5) for activities using hull-
         mounted sonar, the ship concludes that dolphins are
         deliberately closing in on the ship to ride the ship's bow
         wave, and are therefore out of the main transmission axis of
         the sonar (and there are no other marine mammal sightings
         within the mitigation zone).
------------------------------------------------------------------------


[[Page 66960]]

Procedural Mitigation for Air Guns

    Procedural mitigation for air guns is described in Table 47 
below.

              Table 47--Procedural Mitigation for Air Guns
------------------------------------------------------------------------
                    Procedural Mitigation Description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Air guns.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be positioned on a ship or pierside.
Mitigation Requirements:
    <bullet> Mitigation zone:
        --150 yd around the air gun
    <bullet> Prior to the initial start of the activity (e.g., when
     maneuvering on station):
        --Observe the mitigation zone for floating vegetation; if
         floating vegetation is observed, relocate or delay the start
         until the mitigation zone is clear.
        --Observe the mitigation zone for marine mammals; if marine
         mammals are observed, relocate or delay the start of air gun
         use.
    <bullet> During the activity:
        --Observe the mitigation zone for marine mammals; if marine
         mammals are observed, cease air gun use.
    <bullet> Commencement/recommencement conditions after a marine
     mammal sighting before or during the activity:
        --Navy personnel must allow a sighted marine mammal to leave the
         mitigation zone prior to the initial start of the activity (by
         delaying the start) or during the activity (by not recommencing
         air gun use) until one of the following conditions has been
         met: (1) The animal is observed exiting the mitigation zone;
         (2) the animal is thought to have exited the mitigation zone
         based on a determination of its course, speed, and movement
         relative to the air gun; (3) the mitigation zone has been clear
         from any additional sightings for 30 min.; or (4) for mobile
         activities, the air gun has transited a distance equal to
         double that of the mitigation zone size beyond the location of
         the last sighting.
------------------------------------------------------------------------

Procedural Mitigation for Pile Driving

    Procedural mitigation for pile driving is described in Table 48 
below.

            Table 48--Procedural Mitigation for Pile Driving
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Pile driving and pile extraction sound during Elevated
     Causeway System training.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be positioned on the shore, the elevated
     causeway, or a small boat.
Mitigation Requirements:
<bullet> Mitigation zone:
    --100 yd around the pile.
<bullet> Prior to the initial start of the activity (for 30 min.):
    --Observe the mitigation zone for floating vegetation; if floating
     vegetation is observed, delay the start until the mitigation zone
     is clear.
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, delay the start of pile driving or vibratory pile
     extraction.
<bullet> During the activity:
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, cease impact pile driving or vibratory pile
     extraction.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting before or during the activity:
    --Navy personnel must allow a sighted marine mammal to leave the
     mitigation zone prior to the initial start of the activity (by
     delaying the start) or during the activity (by not recommencing
     pile driving or pile extraction) until one of the following
     conditions has been met: (1) The animal is observed exiting the
     mitigation zone; (2) the animal is thought to have exited the
     mitigation zone based on a determination of its course, speed, and
     movement relative to the pile driving location; or (3) the
     mitigation zone has been clear from any additional sightings for 30
     min.
------------------------------------------------------------------------

Procedural Mitigation for Weapons Firing Noise

    Procedural mitigation for weapons firing noise is described in 
Table 49 below.

        Table 49--Procedural Mitigation for Weapons Firing Noise
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Weapons firing noise associated with large-caliber gunnery
     activities.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be positioned on the ship conducting the
     firing.

[[Page 66961]]

 
        --Depending on the activity, the Lookout could be the same one
         provided for under Explosive Medium-Caliber and Large-Caliber
         Projectiles or under Small-, Medium, and Large-Caliber Non-
         Explosive Practice Munitions.
Mitigation Requirements:
<bullet> Mitigation zone:
    --30[deg] on either side of the firing line out to 70 yd from the
     muzzle of the weapon being fired.
<bullet> Prior to the initial start of the activity:
    --Observe the mitigation zone for floating vegetation; if floating
     vegetation is observed, relocate or delay the start of weapons
     firing until the mitigation zone is clear.
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, relocate or delay the start of weapons firing.
<bullet> During the activity:
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, cease weapons firing.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting before or during the activity:
    --Navy personnel must allow a sighted marine mammal to leave the
     mitigation zone prior to the initial start of the activity (by
     delaying the start) or during the activity (by not recommencing
     weapons firing) until one of the following conditions has been met:
     (1) The animal is observed exiting the mitigation zone; (2) the
     animal is thought to have exited the mitigation zone based on a
     determination of its course, speed, and movement relative to the
     firing ship; (3) the mitigation zone has been clear from any
     additional sightings for 30 min.; or (4) for mobile activities, the
     firing ship has transited a distance equal to double that of the
     mitigation zone size beyond the location of the last sighting.
------------------------------------------------------------------------

Procedural Mitigation for Explosive Stressors

    Mitigation measures for explosive stressors are provided in 
Tables 50 through 59.

Procedural Mitigation for Explosive Sonobuoys

    Procedural mitigation for explosive sonobuoys is described in 
Table 50 below.

         Table 50--Procedural Mitigation for Explosive Sonobuoys
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Explosive sonobuoys.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be positioned must be positioned in an
     aircraft or on small boat.
    <bullet> If additional platforms are participating in the activity,
     personnel positioned in those assets (e.g., safety observers,
     evaluators) must support observing the mitigation zone for
     applicable biological resources while performing their regular
     duties.
Mitigation Requirements:
<bullet> Mitigation zone:
    --600 yd around an explosive sonobuoy.
<bullet> Prior to the initial start of the activity (e.g., during
 deployment of a sonobuoy field, which typically lasts 20-30 min.):
    --Observe the mitigation zone for floating vegetation; if floating
     vegetation is observed, relocate or delay the start until the
     mitigation zone is clear.
    --Conduct passive acoustic monitoring for marine mammals; use
     information from detections to assist visual observations.
    --Visually observe the mitigation zone for marine mammals; if marine
     mammals are observed, relocate or delay the start of sonobuoy or
     source/receiver pair detonations.
<bullet> During the activity:
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, cease sonobuoy or source/receiver pair detonations.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting before or during the activity:
    --Navy personnel must allow a sighted marine mammal to leave the
     mitigation zone prior to the initial start of the activity (by
     delaying the start) or during the activity (by not recommencing
     detonations) until one of the following conditions has been met:
     (1) The animal is observed exiting the mitigation zone; (2) the
     animal is thought to have exited the mitigation zone based on a
     determination of its course, speed, and movement relative to the
     sonobuoy; or (3) the mitigation zone has been clear from any
     additional sightings for 10 min. when the activity involves
     aircraft that have fuel constraints, or 30 min. when the activity
     involves aircraft that are not typically fuel constrained.
<bullet> After completion of the activity (e.g., prior to maneuvering
 off station):
    --When practical (e.g., when platforms are not constrained by fuel
     restrictions or mission-essential follow-on commitments), observe
     the vicinity of where detonations occurred; if any injured or dead
     marine mammals are observed, follow established incident reporting
     procedures.
    --If additional platforms are supporting this activity (e.g.,
     providing range clearance), these assets must assist in the visual
     observation of the area where detonations occurred.
------------------------------------------------------------------------

Procedural Mitigation for Explosive Torpedoes

    Procedural mitigation for explosive torpedoes is described in 
Table 51 below.

[[Page 66962]]



         Table 51--Procedural Mitigation for Explosive Torpedoes
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Explosive torpedoes.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be positioned in an aircraft.
    <bullet> If additional platforms are participating in the activity,
     personnel positioned in those assets (e.g., safety observers,
     evaluators) must support observing the mitigation zone for
     applicable biological resources while performing their regular
     duties.
Mitigation Requirements:
<bullet> Mitigation zone:
    --2,100 yd around the intended impact location.
<bullet> Prior to the initial start of the activity (e.g., during
 deployment of the target):
    --Observe the mitigation zone for floating vegetation; if floating
     vegetation is observed, relocate or delay the start until the
     mitigation zone is clear.
    --Conduct passive acoustic monitoring for marine mammals; use
     information from detections to assist visual observations.
    --Visually observe the mitigation zone for marine mammals and
     jellyfish aggregations; if marine mammals or jellyfish aggregations
     are observed, relocate or delay the start of firing.
<bullet> During the activity:
    --Observe the mitigation zone for marine mammals and jellyfish
     aggregations; if marine mammals and jellyfish aggregations are
     observed, cease firing.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting before or during the activity:
    --Navy personnel must allow a sighted marine mammal to leave the
     mitigation zone prior to the initial start of the activity (by
     delaying the start) or during the activity (by not recommencing
     firing) until one of the following conditions has been met: (1) The
     animal is observed exiting the mitigation zone; (2) the animal is
     thought to have exited the mitigation zone based on a determination
     of its course, speed, and movement relative to the intended impact
     location; or (3) the mitigation zone has been clear from any
     additional sightings for 10 min. when the activity involves
     aircraft that have fuel constraints, or 30 min. when the activity
     involves aircraft that are not typically fuel constrained.
<bullet> After completion of the activity (e.g., prior to maneuvering
 off station):
    --When practical (e.g., when platforms are not constrained by fuel
     restrictions or mission-essential follow-on commitments), observe
     the vicinity of where detonations occurred; if any injured or dead
     marine mammals are observed, follow established incident reporting
     procedures.
    --If additional platforms are supporting this activity (e.g.,
     providing range clearance), these assets must assist in the visual
     observation of the area where detonations occurred.
------------------------------------------------------------------------

Procedural Mitigation for Medium- and Large-Caliber Projectiles

    Procedural mitigation for medium- and large-caliber projectiles 
is described in Table 52 below.

 Table 52--Procedural Mitigation for Explosive Medium-Caliber and Large-
                           Caliber Projectiles
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Gunnery activities using explosive medium-caliber and large-
     caliber projectiles.
        --Mitigation applies to activities using a surface target.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be on the vessel or aircraft conducting the
     activity.
        --For activities using explosive large-caliber projectiles,
         depending on the activity, the Lookout could be the same as the
         one described for Weapons Firing Noise.
    <bullet> If additional platforms are participating in the activity,
     Navy personnel positioned in those assets (e.g., safety observers,
     evaluators) must support observing the mitigation zone for
     applicable biological resources while performing their regular
     duties.
Mitigation Requirements:
<bullet> Mitigation zones:
    --200 yd around the intended impact location for air-to-surface
     activities using explosive medium-caliber projectiles.
    --600 yd around the intended impact location for surface-to-surface
     activities using explosive medium-caliber projectiles.
    --1,000 yd around the intended impact location for surface-to-
     surface activities using explosive large-caliber projectiles.
<bullet> Prior to the initial start of the activity (e.g., when
 maneuvering on station):
    --Observe the mitigation zone for floating vegetation; if floating
     vegetation is observed, relocate or delay the start until the
     mitigation zone is clear.
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, relocate or delay the start of firing.
<bullet> During the activity:
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, cease firing.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting before or during the activity:
    --Navy personnel must allow a sighted marine mammal to leave the
     mitigation zone prior to the initial start of the activity (by
     delaying the start) or during the activity (by not recommencing
     firing) until one of the following conditions has been met: (1) The
     animal is observed exiting the mitigation zone; (2) the animal is
     thought to have exited the mitigation zone based on a determination
     of its course, speed, and movement relative to the intended impact
     location; (3) the mitigation zone has been clear from any
     additional sightings for 10 min. for aircraft-based firing or 30
     min. for vessel-based firing; or (4) for activities using mobile
     targets, the intended impact location has transited a distance
     equal to double that of the mitigation zone size beyond the
     location of the last sighting.
<bullet> After completion of the activity (e.g., prior to maneuvering
 off station):

[[Page 66963]]

 
    --When practical (e.g., when platforms are not constrained by fuel
     restrictions or mission-essential follow-on commitments), observe
     the vicinity of where detonations occurred; if any injured or dead
     marine mammals are observed, follow established incident reporting
     procedures.
    --If additional platforms are supporting this activity (e.g.,
     providing range clearance), these assets must assist in the visual
     observation of the area where detonations occurred.
------------------------------------------------------------------------

Procedural Mitigation for Explosive Missiles and Rockets

    Procedural mitigation for explosive missiles and rockets is 
described in Table 53 below.

   Table 53--Procedural Mitigation for Explosive Missiles and Rockets
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Aircraft-deployed explosive missiles and rockets.
        --Mitigation applies to activities using a surface target.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be positioned in an aircraft.
    <bullet> If additional platforms are participating in the activity,
     Navy personnel positioned in those assets (e.g., safety observers,
     evaluators) must support observing the mitigation zone for
     applicable biological resources while performing their regular
     duties.
Mitigation Requirements:
<bullet> Mitigation zones:
    --900 yd around the intended impact location for missiles or rockets
     with 0.6-20 lb. net explosive weight.
    --2,000 yd around the intended impact location for missiles with 21-
     500 lb. net explosive weight.
<bullet> Prior to the initial start of the activity (e.g., during a fly-
 over of the mitigation zone):
    --Observe the mitigation zone for floating vegetation; if floating
     vegetation is observed, relocate or delay the start until the
     mitigation zone is clear.
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, relocate or delay the start of firing.
<bullet> During the activity:
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, cease firing.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting before or during the activity:
    --Navy personnel must allow a sighted marine mammal to leave the
     mitigation zone prior to the initial start of the activity (by
     delaying the start) or during the activity (by not recommencing
     firing) until one of the following conditions has been met: (1) The
     animal is observed exiting the mitigation zone; (2) the animal is
     thought to have exited the mitigation zone based on a determination
     of its course, speed, and movement relative to the intended impact
     location; or (3) the mitigation zone has been clear from any
     additional sightings for 10 min. when the activity involves
     aircraft that have fuel constraints, or 30 min. when the activity
     involves aircraft that are not typically fuel constrained.
<bullet> After completion of the activity (e.g., prior to maneuvering
 off station):
    --When practical (e.g., when platforms are not constrained by fuel
     restrictions or mission-essential follow-on commitments), observe
     for marine mammals in the vicinity of where detonations occurred;
     if any injured or dead marine mammals are observed, follow
     established incident reporting procedures.
    --If additional platforms are supporting this activity (e.g.,
     providing range clearance), these assets must assist in the visual
     observation of the area where detonations occurred.
------------------------------------------------------------------------

Procedural Mitigation for Explosive Bombs

    Procedural mitigation for explosive bombs is described in Table 
54 below.

           Table 54--Procedural Mitigation for Explosive Bombs
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Explosive bombs.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be positioned in the aircraft conducting the
     activity.
    <bullet> If additional platforms are participating in the activity,
     Navy personnel positioned in those assets (e.g., safety observers,
     evaluators) must support observing the mitigation zone for
     applicable biological resources while performing their regular
     duties.
Mitigation Requirements:
<bullet> Mitigation zone:
    --2,500 yd around the intended target.
<bullet> Prior to the initial start of the activity (e.g., when arriving
 on station):
    --Observe the mitigation zone for floating vegetation; if floating
     vegetation is observed, relocate or delay the start of bomb
     deployment until the mitigation zone is clear.

[[Page 66964]]

 
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, relocate or delay the start of bomb deployment.
<bullet> During the activity (e.g., during target approach):
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, cease bomb deployment.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting before or during the activity:
    --Navy personnel must allow a sighted marine mammal to leave the
     mitigation zone prior to the initial start of the activity (by
     delaying the start) or during the activity (by not recommencing
     bomb deployment) until one of the following conditions has been
     met: (1) The animal is observed exiting the mitigation zone; (2)
     the animal is thought to have exited the mitigation zone based on a
     determination of its course, speed, and movement relative to the
     intended target; (3) the mitigation zone has been clear from any
     additional sightings for 10 min.; or (4) for activities using
     mobile targets, the intended target has transited a distance equal
     to double that of the mitigation zone size beyond the location of
     the last sighting.
<bullet> After completion of the activity (e.g., prior to maneuvering
 off station):
    --When practical (e.g., when platforms are not constrained by fuel
     restrictions or mission-essential follow-on commitments), observe
     for marine mammals in the vicinity of where detonations occurred;
     if any injured or dead marine mammals are observed, follow
     established incident reporting procedures.
    --If additional platforms are supporting this activity (e.g.,
     providing range clearance), these assets must assist in the visual
     observation of the area where detonations occurred.
------------------------------------------------------------------------

Procedural Mitigation for Sinking Exercises

    Procedural mitigation for sinking exercises is described in 
Table 55 below.

          Table 55--Procedural Mitigation for Sinking Exercises
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Sinking exercises.
Number of Lookouts and Observation Platform:
    <bullet> 2 Lookouts (one must be positioned in an aircraft and one
     must be on a vessel).
    <bullet> If additional platforms are participating in the activity,
     Navy personnel positioned in those assets (e.g., safety observers,
     evaluators) must support observing the mitigation zone for
     applicable biological resources while performing their regular
     duties.
Mitigation Requirements:
<bullet> Mitigation zone:
    --2.5 nmi around the target ship hulk.
<bullet> Prior to the initial start of the activity (90 min. prior to
 the first firing):
    --Conduct aerial observations of the mitigation zone for floating
     vegetation; delay the start of firing until the mitigation zone is
     clear.
    --Conduct aerial observations of the mitigation zone for marine
     mammals and jellyfish aggregations; if marine mammals or jellyfish
     aggregations are observed, delay the start of firing.
<bullet> During the activity:
    --Conduct passive acoustic monitoring for marine mammals; use
     information from detections to assist visual observations.
    --Visually observe the mitigation zone for marine mammals from the
     vessel; if marine mammals are observed, Navy personnel must cease
     firing.
    --Immediately after any planned or unplanned breaks in weapons
     firing of longer than 2 hours, observe the mitigation zone for
     marine mammals from the aircraft and vessel; if marine mammals are
     observed, Navy personnel must delay recommencement of firing.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting before or during the activity:
    --The Navy must allow a sighted marine mammal to leave the
     mitigation zone prior to the initial start of the activity (by
     delaying the start) or during the activity (by not recommencing
     firing) until one of the following conditions has been met: (1) The
     animal is observed exiting the mitigation zone; (2) the animal is
     thought to have exited the mitigation zone based on a determination
     of its course, speed, and movement relative to the target ship
     hulk; or (3) the mitigation zone has been clear from any additional
     sightings for 30 min.
<bullet> After completion of the activity (for 2 hours after sinking the
 vessel or until sunset, whichever comes first):
    --Observe for marine mammals in the vicinity of where detonations
     occurred; if any injured or dead marine mammals are observed, Navy
     personnel must follow established incident reporting procedures.
    --If additional platforms are supporting this activity (e.g.,
     providing range clearance), these assets must assist in the visual
     observation of the area where detonations occurred.
------------------------------------------------------------------------

Procedural Mitigation for Explosive Mine Countermeasure and 
Neutralization Activities

    Procedural mitigation for explosive mine countermeasure and 
neutralization activities is described in Table 56 below.

  Table 56--Procedural Mitigation for Explosive Mine Countermeasure and
                        Neutralization Activities
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:

[[Page 66965]]

 
    <bullet> Explosive mine countermeasure and neutralization
     activities.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be positioned on a vessel or in an aircraft
     when implementing the smaller mitigation zone.
    <bullet> 2 Lookouts (one must be positioned in an aircraft and one
     must be on a small boat) when implementing the larger mitigation
     zone.
    <bullet> If additional platforms are participating in the activity,
     Navy personnel positioned in those assets (e.g., safety observers,
     evaluators) must support observing the mitigation zone for
     applicable biological resources while performing their regular
     duties.
Mitigation Requirements:
<bullet> Mitigation zones:
    --600 yd around the detonation site for activities using 0.1-5-lb
     net explosive weight.
    --2,100 yd around the detonation site for activities using 6-650 lb
     net explosive weight (including high explosive target mines).
<bullet> Prior to the initial start of the activity (e.g., when
 maneuvering on station; typically, 10 min when the activity involves
 aircraft that have fuel constraints, or 30 min when the activity
 involves aircraft that are not typically fuel constrained):
    --Observe the mitigation zone for floating vegetation; if floating
     vegetation is observed, relocate or delay the start of detonations
     until the mitigation zone is clear.
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, relocate or delay the start of detonations.
<bullet> During the activity:
    --Observe the mitigation zone for marine mammals, concentrations of
     seabirds, and individual foraging seabirds; if for marine mammals,
     concentrations of seabirds, and individual foraging seabirds are
     observed, cease detonations.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting before or during the activity or a sighting of seabird
 concentrations or individual foraging seabirds during the activity:
    --Navy personnel must allow a sighted animal to leave the mitigation
     zone prior to the initial start of the activity (by delaying the
     start) or during the activity (by not recommencing detonations)
     until one of the following conditions has been met: (1) The animal
     is observed exiting the mitigation zone; (2) the animal is thought
     to have exited the mitigation zone based on a determination of its
     course, speed, and movement relative to detonation site; or (3) the
     mitigation zone has been clear from any additional sightings for 10
     min. when the activity involves aircraft that have fuel
     constraints, or 30 min. when the activity involves aircraft that
     are not typically fuel constrained.
<bullet> After completion of the activity (typically 10 min. when the
 activity involves aircraft that have fuel constraints, or 30 min. when
 the activity involves aircraft that are not typically fuel
 constrained):
    --Observe for marine mammals in the vicinity of where detonations
     occurred; if any injured or dead marine mammals are observed,
     follow established incident reporting procedures.
    --If additional platforms are supporting this activity (e.g.,
     providing range clearance), these assets must assist in the visual
     observation of the area where detonations occurred.
------------------------------------------------------------------------

Procedural Mitigation for Explosive Mine Neutralization Activities 
Involving Navy Divers

    Procedural mitigation for explosive mine neutralization 
activities involving Navy divers is described in Table 57 below.

    Table 57--Procedural Mitigation for Explosive Mine Neutralization
                    Activities Involving Navy Divers
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Explosive mine neutralization activities involving Navy
     divers.
Number of Lookouts and Observation Platform:
    <bullet> 2 Lookouts (two small boats with one Lookout each, or one
     Lookout must be on a small boat and one must be in a rotary-wing
     aircraft) when implementing the smaller mitigation zone.
    <bullet> 4 Lookouts (two small boats with two Lookouts each), and a
     pilot or member of an aircrew must serve as an additional Lookout
     if aircraft are used during the activity, when implementing the
     larger mitigation zone.
    <bullet> All divers placing the charges on mines must support the
     Lookouts while performing their regular duties and must report
     applicable sightings to their supporting small boat or Range Safety
     Officer.
    <bullet> If additional platforms are participating in the activity,
     Navy personnel positioned in those assets (e.g., safety observers,
     evaluators) must support observing the mitigation zone for
     applicable biological resources while performing their regular
     duties.
Mitigation Requirements:
<bullet> Mitigation zones:
    --500 yd around the detonation site during activities under positive
     control using 0.1-20 lb net explosive weight.
    --1,000 yd around the detonation site during activities using time-
     delay fuses (0.1-29 lb net explosive weight) and during activities
     under positive control using 21-60 lb net explosive weight charges.
<bullet> Prior to the initial start of the activity (e.g., when
 maneuvering on station for activities under positive control; 30 min.
 for activities using time-delay firing devices):
    --Observe the mitigation zone for floating vegetation; if floating
     vegetation is observed, relocate or delay the start of detonations
     or fuse initiation until the mitigation zone is clear.
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, relocate or delay the start of detonations or fuse
     initiation.
<bullet> During the activity:

[[Page 66966]]

 
    --Observe the mitigation zone for marine mammals, concentrations of
     seabirds, and individual foraging seabirds (in the water and not on
     shore); if marine mammals, concentrations of seabirds, and
     individual foraging seabirds are observed, cease detonations or
     fuse initiation.
    --To the maximum extent practicable depending on mission
     requirements, safety, and environmental conditions, Navy must
     position boats mustnear the mid-point of the mitigation zone radius
     (but outside of the detonation plume and human safety zone), must
     position themselves on opposite sides of the detonation location
     (when two boats are used), and must travel in a circular pattern
     around the detonation location with one Lookout observing inward
     toward the detonation site and the other observing outward toward
     the perimeter of the mitigation zone.
    --If used, aircraft must travel in a circular pattern around the
     detonation location to the maximum extent practicable.
    --Navy personnel must not set time-delay firing devices (0.1-29 lb.
     net explosive weight) to exceed 10 min.
    --During activities conducted in shallow water, a shore-based
     observer must survey the mitigation zone with binoculars for birds
     before and after each detonation. If training involves multiple
     detonations, the second (or third, etc.) detonation must occur
     either immediately after the preceding detonation (i.e., within 10
     seconds) or after 30 min. to avoid potential impacts on birds
     foraging underwater.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting before or during the activity or a sighting of seabird
 concentrations or individual foraging seabirds during the activity:
    --Navy personnel must allow a sighted animal to leave the mitigation
     zone prior to the initial start of the activity (by delaying the
     start) or during the activity (by not recommencing detonations)
     until one of the following conditions has been met: (1) The animal
     is observed exiting the mitigation zone; (2) the animal is thought
     to have exited the mitigation zone based on a determination of its
     course, speed, and movement relative to the detonation site; or (3)
     the mitigation zone has been clear from any additional sightings
     for 10 min. during activities under positive control with aircraft
     that have fuel constraints, or 30 min. during activities under
     positive control with aircraft that are not typically fuel
     constrained and during activities using time-delay firing devices.
<bullet> After completion of an activity (for 30 min):
    --Observe for marine mammals in the vicinity of where detonations
     occurred; if any injured or dead marine mammals are observed,
     follow established incident reporting procedures.
    --If additional platforms are supporting this activity (e.g.,
     providing range clearance), these assets must assist in the visual
     observation of the area where detonations occurred.
------------------------------------------------------------------------

Procedural Mitigation for Underwater Demolition Multiple Charge--Mat 
Weave and Obstacle Loading

    Procedural mitigation for underwater demolition multiple 
charge--mat weave and obstacle loading is described in Table 58 
below.

   Table 58--Procedural Mitigation for Underwater Demolition Multiple
                 Charge--Mat Weave and Obstacle Loading
------------------------------------------------------------------------
                    Procedural Mitigation Description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Underwater Demolition Multiple Charge--Mat Weave and
     Obstacle Loading exercises.
Number of Lookouts and Observation Platform:
    <bullet> 2 Lookouts (one must be on a small boat and one must be on
     shore from an elevated platform).
    <bullet> If additional platforms are participating in the activity,
     Navy personnel positioned in those assets (e.g., safety observers,
     evaluators) must support observing the mitigation zone for
     applicable biological resources while performing their regular
     duties.
Mitigation Requirements:
<bullet> Mitigation zone:
    --700 yd around the detonation location.
<bullet> Prior to the initial start of the activity:
    --For 30 min. prior to the first detonation, the Lookout positioned
     on a small boat must observe the mitigation zone for floating
     vegetation and marine mammals; if floating vegetation or marine
     mammals are observed, delay the start of detonations.
    --For 10 min. prior to the first detonation, the Lookout positioned
     on shore must use binoculars to observe the mitigation zone for
     marine mammals; if marine mammals are observed, delay the start of
     detonations until the mitigation zone has been clear of any
     additional sightings for a minimum of 10 min.
<bullet> During the activity:
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, cease detonations.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting before or during the activity:
    --Navy personnel must allow a sighted marine mammal to leave the
     mitigation zone prior to the initial start of the activity (by
     delaying the start) or during the activity (by not recommencing
     detonations) until one of the following conditions has been met:
     (1) The animal is observed exiting the mitigation zone; (2) the
     animal is thought to have exited the mitigation zone based on a
     determination of its course, speed, and movement relative to the
     detonation location; or (3) the mitigation zone has been clear from
     any additional sightings for 10 min. (as determined by the shore
     observer).
<bullet> After completion of the activity (for 30 min.):
    --The Lookout positioned on a small boat must observe for marine
     mammals in the vicinity of where detonations occurred; if any
     injured or dead marine mammals are observed, Navy personnel must
     follow established incident reporting procedures.
    --If additional platforms are supporting this activity (e.g.,
     providing range clearance), these assets must assist in the visual
     observation of the area where detonations occurred.
------------------------------------------------------------------------


[[Page 66967]]

Procedural Mitigation for Maritime Security Operations--Anti-Swimmer 
Grenades

    Procedural mitigation for maritime security operations--anti-
swimmer grenades is described in Table 59 below.

 Table 59--Procedural Mitigation for Maritime Security Operations--Anti-
                            Swimmer Grenades
------------------------------------------------------------------------
                    Procedural Mitigation Description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Maritime Security Operations--Anti-Swimmer Grenades.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be positioned on the small boat conducting
     the activity.
    <bullet> If additional platforms are participating in the activity,
     Navy personnel positioned in those assets (e.g., safety observers,
     evaluators) must support observing the mitigation zone for
     applicable biological resources while performing their regular
     duties.
Mitigation Requirements:
<bullet> Mitigation zone:
    --200 yd around the intended detonation location.
<bullet> Prior to the initial start of the activity (e.g., when
 maneuvering on station):
    --Observe the mitigation zone for floating vegetation; if floating
     vegetation is observed, relocate or delay the start of detonations
     until the mitigation zone is clear.
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, relocate or delay the start of detonations.
<bullet> During the activity:
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, cease detonations.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting before or during the activity:
    --Navy personnel must allow a sighted marine mammal to leave the
     mitigation zone prior to the initial start of the activity (by
     delaying the start) or during the activity (by not recommencing
     detonations) until one of the following conditions has been met:
     (1) The animal is observed exiting the mitigation zone; (2) the
     animal is thought to have exited the mitigation zone based on a
     determination of its course, speed, and movement relative to the
     intended detonation location; (3) the mitigation zone has been
     clear from any additional sightings for 30 min.; or (4) the
     intended detonation location has transited a distance equal to
     double that of the mitigation zone size beyond the location of the
     last sighting.
<bullet> After completion of the activity (e.g., prior to maneuvering
 off station):
    --When practical (e.g., when platforms are not constrained by fuel
     restrictions or mission-essential follow-on commitments), observe
     for marine mammals in the vicinity of where detonations occurred;
     if any injured or dead marine mammals are observed, follow
     established incident reporting procedures.
    --If additional platforms are supporting this activity (e.g.,
     providing range clearance), these assets must assist in the visual
     observation of the area where detonations occurred.
------------------------------------------------------------------------

Procedural Mitigation for Physical Disturbance and Strike Stressors

    Mitigation measures for physical disturbance and strike 
stressors are provided in Table 60 through Table 64.

Procedural Mitigation for Vessel Movement

    Procedural mitigation for vessel movement is described in Table 
60 below.

           Table 60--Procedural Mitigation for Vessel Movement
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Vessel movement:
    --The mitigation must not be applied if: (1) The vessel's safety is
     threatened, (2) the vessel is restricted in its ability to maneuver
     (e.g., during launching and recovery of aircraft or landing craft,
     during towing activities, when mooring), (3) the vessel is operated
     autonomously, or (4) when impractical based on mission requirements
     (e.g., during Amphibious Assault--Battalion Landing exercises).
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be on the vessel that is underway.
Mitigation Requirements:
    <bullet> Mitigation zones:
    --500 yd around whales.
    --200 yd around other marine mammals (except bow-riding dolphins and
     pinnipeds hauled out on man-made navigational structures, port
     structures, and vessels).
<bullet> During the activity:
    --When underway, observe the mitigation zone for marine mammals; if
     marine mammals are observed, Navy personnel must maneuver to
     maintain distance.
<bullet> Additional requirements:
    --If a marine mammal vessel strike occurs, Navy personnel must
     follow the established incident reporting procedures.
------------------------------------------------------------------------


[[Page 66968]]

Procedural Mitigation for Towed In-Water Devices

    Procedural mitigation for towed in-water devices is described in 
Table 61 below.

       Table 61--Procedural Mitigation for Towed In-Water Devices
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Towed in-water devices:
    --Mitigation applies to devices that are towed from a manned surface
     platform or manned aircraft.
    --The mitigation must not be applied if the safety of the towing
     platform or in-water device is threatened.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be positioned on the manned towing platform.
Mitigation Requirements:
    <bullet> Mitigation zones:
    --250 yd around marine mammals.
<bullet> During the activity (i.e., when towing an in-water device):
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, Navy personnel must maneuver to maintain distance.
------------------------------------------------------------------------

Procedural Mitigation for Small-, Medium-, and Large-Caliber Non-
Explosive Practice Munitions

    Procedural mitigation for small-, medium-, and large-caliber 
non-explosive practice munitions is described in Table 62 below.

 Table 62--Procedural Mitigation for Small-, Medium-, and Large-Caliber
                    Non-Explosive Practice Munitions
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Gunnery activities using small-, medium-, and large-caliber
     non-explosive practice munitions:
    --Mitigation applies to activities using a surface target.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be positioned on the platform conducting the
     activity.
        --Depending on the activity, the Lookout could be the same as
         the one described for Weapons Firing Noise.
Mitigation Requirements:
<bullet> Mitigation zone:
    --200 yd around the intended impact location.
<bullet> Prior to the initial start of the activity (e.g., when
 maneuvering on station):
    --Observe the mitigation zone for floating vegetation; if floating
     vegetation is observed, relocate or delay the start of firing until
     the mitigation zone is clear.
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, relocate or delay the start of firing.
<bullet> During the activity:
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, cease firing.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting before or during the activity:
    --Navy personnel must allow a sighted marine mammal to leave the
     mitigation zone prior to the initial start of the activity (by
     delaying the start) or during the activity (by not recommencing
     firing) until one of the following conditions has been met: (1) The
     animal is observed exiting the mitigation zone; (2) the animal is
     thought to have exited the mitigation zone based on a determination
     of its course, speed, and movement relative to the intended impact
     location; (3) the mitigation zone has been clear from any
     additional sightings for 10 min. for aircraft-based firing or 30
     min. for vessel-based firing; or (4) for activities using a mobile
     target, the intended impact location has transited a distance equal
     to double that of the mitigation zone size beyond the location of
     the last sighting.
------------------------------------------------------------------------

Procedural Mitigation for Non-Explosive Missiles and Rockets

    Procedural mitigation for non-explosive missiles and rockets is 
described in Table 63 below.

 Table 63--Procedural Mitigation for Non-Explosive Missiles and Rockets
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
<bullet> Aircraft-deployed non-explosive missiles and rockets:
    --Mitigation applies to activities using a surface target.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be positioned in an aircraft.

[[Page 66969]]

 
Mitigation Requirements:
<bullet> Mitigation zone:
    --900 yd around the intended impact location.
<bullet> Prior to the initial start of the activity (e.g., during a fly-
 over of the mitigation zone):
    --Observe the mitigation zone for floating vegetation; if floating
     vegetation is observed, relocate or delay the start of firing until
     the mitigation zone is clear.
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, relocate or delay the start of firing.
<bullet> During the activity:
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, cease firing.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting prior to or during the activity:
    --Navy personnel must allow a sighted marine mammal to leave the
     mitigation zone prior to the initial start of the activity (by
     delaying the start) or during the activity (by not recommencing
     firing) until one of the following conditions has been met: (1) The
     animal is observed exiting the mitigation zone; (2) the animal is
     thought to have exited the mitigation zone based on a determination
     of its course, speed, and movement relative to the intended impact
     location; or (3) the mitigation zone has been clear from any
     additional sightings for 10 min. when the activity involves
     aircraft that have fuel constraints, or 30 min. when the activity
     involves aircraft that are not typically fuel constrained.
------------------------------------------------------------------------

Procedural Mitigation for Non-Explosive Bombs and Mine Shapes

    Procedural mitigation for non-explosive bombs and mine shapes is 
described in Table 64 below.

 Table 64--Procedural Mitigation for Non-Explosive Bombs and Mine Shapes
------------------------------------------------------------------------
                    Procedural mitigation description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Non-explosive bombs.
    <bullet> Non-explosive mine shapes during mine laying activities.
Number of Lookouts and Observation Platform:
    <bullet> 1 Lookout must be positioned in an aircraft.
Mitigation Requirements:
<bullet> Mitigation zone:
    --1,000 yd around the intended target.
<bullet> Prior to the start of the activity (e.g., when arriving on
 station):
    --Observe the mitigation zone for floating vegetation; if floating
     vegetation is observed, relocate or delay the start of bomb
     deployment or mine laying until the mitigation zone is clear.
    --Observe the mitigation zone for marine mammals; if marine mammals
     are observed, relocate or delay the start of bomb deployment or
     mine laying.
<bullet> During the activity (e.g., during approach of the target or
 intended minefield location):
    --Observe the mitigation zone for marine mammals and; if marine
     mammals are observed, cease bomb deployment or mine laying.
<bullet> Commencement/recommencement conditions after a marine mammal
 sighting prior to or during the activity:
    --Navy personnel must allow a sighted marine mammal to leave the
     mitigation zone prior to the initial start of the activity (by
     delaying the start) or during the activity (by not recommencing
     bomb deployment or mine laying) until one of the following
     conditions has been met: (1) The animal is observed exiting the
     mitigation zone; (2) the animal is thought to have exited the
     mitigation zone based on a determination of its course, speed, and
     movement relative to the intended target or minefield location; (3)
     the mitigation zone has been clear from any additional sightings
     for 10 min.; or (4) for activities using mobile targets, the
     intended target has transited a distance equal to double that of
     the mitigation zone size beyond the location of the last sighting.
------------------------------------------------------------------------

Final Mitigation Areas

    In addition to procedural mitigation, the Navy will implement 
mitigation measures within mitigation areas to avoid or minimize 
potential impacts on marine mammals (see Figures 2 and 4 above and 
the revised figures provided in the HSTT FEIS/OEIS for specific 
information on the location and boundaries of each mitigation area). 
A full technical analysis (for which the methods were summarized 
above) of the mitigation areas that the Navy considered for marine 
mammals is provided in Appendix K (Geographic Mitigation Assessment) 
of the HSTT FEIS/OEIS. The Navy has taken into account public 
comments received on the HSTT DEIS/OEIS, best available science, and 
the practicability of implementing additional mitigation measures 
and has enhanced its mitigation areas and mitigation measures to 
further reduce impacts to marine mammals. The Navy has therefore 
revised their mitigation areas since their application (changes 
noted at the beginning of this section). The Navy re-analyzed 
existing mitigation areas and considered new habitat areas suggested 
by the public, NMFS, and other non-governmental organizations, 
including main Hawaiian Islands insular false killer whale ESA 
designated critical habitat, important habitat for large whales in 
SOCAL, BIAs, and National Marine Sanctuaries. The Navy worked 
collaboratively with NMFS to develop mitigation areas using inputs 
from the Navy's operational community, the best available science 
discussed in Chapter 3 of the HSTT FEIS/OEIS (Affected Environment 
and Environmental Consequences section), published literature, 
predicted activity impact footprints, marine species monitoring and 
density data, and the practicability of implementing additional 
mitigations.
    NMFS conducted an independent analysis of the mitigation areas 
that the Navy will implement and that are included in this rule, 
which are described below. NMFS concurs with the Navy's analysis, 
which indicates that the measures in these mitigation areas are both 
practicable and will reduce the likelihood or severity of adverse 
impacts to marine mammal species or stocks or their habitat in the 
manner described in the Navy's analysis and this rule. We note that 
NMFS is

[[Page 66970]]

heavily reliant on the Navy's assessment of practicability, since 
the Navy is best equipped to judge the degree to which a given 
mitigation measure affects personnel safety or mission 
effectiveness, and is practical to implement. The Navy considers the 
measures in this rule to be practicable. We further describe and 
summarize the manner in which the Area Mitigations in the rule will 
reduce the likelihood or severity of adverse impacts to marine 
mammal species or stocks or their habitat below.

Mitigation Areas in Hawaii

    Hawaii Island Mitigation Area: The Navy will not use more than 
300 hours of MF1 surface hull-mounted MFAS (the source that results 
in, by far, the highest numbers of take) or 20 hours of MF4 dipping 
sonar in a year, or explosives across this large area at any time of 
the year. This mitigation area overlaps the entirety of several 
small, resident populations (BIAs) of odontocetes that occur only 
around the island of Hawaii (Hawaii stocks of dwarf sperm whale, 
pygmy killer whale, short-finned pilot whale, melon-headed whale, 
bottlenose dolphin, and Blaineville's beaked whale) and about 80 and 
90 percent, respectively, of the Hawaii stocks of the rough-toothed 
dolphin and Cuvier's beaked whale. For small resident populations, 
we aim to avoid overwhelming small populations (which are more 
susceptible to certain adverse impacts on population rates of growth 
and survival, such as Allee effects) with large scale impacts, 
especially when the population is limited to a small area and less 
able to access alternative habitat. By minimizing exposure to the 
most impactful sonar sources and not using explosives, both the 
magnitude and severity of both behavioral impacts and potential 
hearing impairment are greatly reduced. There are also several small 
resident populations (BIAs) of odontocetes that span multiple 
islands, and this mitigation area overlaps all of the stock's range 
around the island of Hawaii for false killer whales (Main Hawaiian 
Island insular stock) and spinner dolphins (Hawaiian Islands stock), 
and about 90 percent of the range around the island of Hawaii for 
pantropical spotted dolphins (Hawaii stock). Additionally, critical 
habitat has been designated, pursuant to the ESA, for false killer 
whales (Main Hawaiian Island insular stock) in waters between 45 and 
3,200 meters depth around all of the main Hawaiian islands, and this 
mitigation area captures more than 95 percent of this area around 
the island of Hawaii. Stocks that span multiple islands and have 
larger total area within their range are generally considered 
somewhat less vulnerable than those with smaller ranges, but 
nonetheless, this mitigation area (along with the addition of the 4-
Islands Mitigation Area discussed immediately below) offers 
significant reduction of impacts to these stocks.
    This mitigation area also overlaps an important breeding and 
calving area (BIA) for the Central North Pacific stock of humpback 
whales (of note, the BIA entirely contains, and is slightly larger 
than, the Hawaii Humpback Whale National Marine Sanctuary). This BIA 
includes areas adjacent to all of the Main Hawaiian Islands, and 
this mitigation area encompasses the important area adjacent to the 
island of Hawaii. For humpback whales, the reduction of activities 
and associated impacts (behavioral disturbance or TTS) in this area 
for individuals that have calves or are potentially breeding is 
expected to reduce the probability or severity of impacts that would 
be more likely to adversely impact reproduction or survival of 
individuals by directly interfering with breeding behaviors or by 
separating mothers and calves at a time when calves are more 
susceptible to predators and less able to care for and feed 
themselves.
    Critical habitat has been designated, pursuant to the ESA, for 
the Hawaiian monk seal from the shore out to the 200-m depth line 
(but only between the bottom and 10 meters above the bottom) in 
multiple areas on 10 islands of the Northwestern Hawaiian Islands 
and six islands of the Main Hawaiian Islands. These areas include: 
(1) Significant coastal areas where seals haul out for resting, 
molting, socializing, and avoiding predators; (2) preferred coastal 
and marine nursery grounds where seals haul out for pupping and 
nursing, and (3) marine areas where seals hunt and feed. This 
mitigation area overlaps all of their critical habitat around the 
Island of Hawaii and, by not using explosives or the most impactful 
sonar sources in this area, thereby reduces the likelihood that take 
might impact reproduction or survival by interfering with important 
feeding or resting behaviors (potentially having adverse impacts on 
energy budgets) or separating mothers and pups in times when pups 
are more susceptible to predation and less able to feed or otherwise 
take care of themselves.
    4-Islands Region Mitigation Area: The Navy will not use MF1 
surface hull-mounted MFAS (the source that results in, by far, the 
highest numbers of take) from November 15 through April 15 or use 
explosives in this area at any time of the year. The Maui/Molokai 
area (4-Islands Region) is an important reproductive and calving 
area for humpback whales (another section of the BIA, and including 
a greater area than the Hawaii island section), and the mitigation 
area overlaps the entirety of this BIA between the islands of Maui, 
Molokai, Lanai, and Kaho'alawe. As noted above, the reduction of 
activities in this area with individuals that have calves or are 
potentially breeding is expected to reduce the probability or 
severity of impacts that would be more likely to adversely impact 
reproduction or survival of individuals by directly interfering with 
breeding behaviors or by separating mothers and calves at a time 
when calves are more susceptible to predators and less able to care 
for and feed themselves.
    In addition, as noted above, there are also several small 
resident populations of marine mammals (BIAs) that span multiple 
islands, and this mitigation area overlaps about 80 percent of the 
pantropical spotted dolphin (Hawaii stock) area adjacent to these 
four islands (one of three discrete areas of the BIA), about 40 
percent of the portion of the false killer whale's (Main Hawaiian 
Island insular stock) range that spans an area north of Molokai and 
Maui (one of the two significantly larger areas that comprise the 
false killer whale BIA), and a good portion of the BIA for spinner 
dolphins (Hawaiian Islands stock), which spans the Main Hawaiian 
Islands in one large continuous area. As noted above, the critical 
habitat for false killer whales extends fairly far out (to 3,200 
meters depth) around all the Main Hawaiian Islands. As described in 
the Hawaii Island Mitigation Area section above, by limiting 
exposure to the most impactful sonar source and explosives for these 
stocks, in this 4-Islands Region Mitigation Area in addition to the 
Hawaii Island Mitigation Area both the magnitude and severity of 
both behavioral impacts and potential hearing impairment are greatly 
reduced.
    Also as noted first above, critical habitat has been designated 
for the Hawaiian monk seal from the shore out to the 200-m depth 
line around the four islands targeted with this mitigation area. The 
mitigation area overlaps more than half of the critical habitat 
around these four islands and by not using explosives or the most 
impactful sonar sources in this area, the likelihood that take might 
impact reproduction or survival by interfering with important 
feeding or resting behaviors (potentially having adverse impacts on 
energy budgets) or separating mothers and pups in times when pups 
are more susceptible to predation and less able to feed or otherwise 
take care of themselves is greatly reduced.
    Humpback Whale Awareness Notification Message Area: The Navy 
will issue a seasonal awareness notification message that will alert 
Navy ships and aircraft in the area of the possible presence of 
whales and instruct them to remain vigilant to the presence of large 
whales that when seasonally concentrated (like humpbacks) may become 
vulnerable to vessel strikes. The message is issued to all vessels 
in Hawaii from November through April. This message will further 
increase the vigilance of Navy Lookouts in a place and time where 
humpback whale density is high, which will further reduce the chance 
that a humpback whale (or other large whale) may be struck.
    Humpback Whale Special Reporting Areas: The Navy will report the 
total hours of surface ship hull-mounted MFAS used between December 
15 and April 15 in three special reporting areas, including Penguin 
Banks and two other much smaller areas that also overlap the 
humpback whale BIA. These reporting areas are not mitigation areas, 
however, we describe them here because they were identified in order 
to inform the adaptive management process. Specifically, Penguin 
Bank is an area with high humpback whale density that is also 
critical for Navy training and testing. Because of the 
impracticability of implementing activity limitations in this 
important area, we designated this reporting requirement so that 
NMFS could remain aware of the level of activity in the area and 
revisit mitigation discussions, if appropriate. To date the Navy's 
reporting has not lead to changes in NMFS' least practicable adverse 
impact analysis for the mitigation in this area.

Mitigation Areas Off the U.S. West Coast

    Santa Barbara Island Mitigation Area (Year-round): The Navy will 
not use ship hull-mounted MFAS during training or testing (the 
source responsible for the most

[[Page 66971]]

take), or explosives during medium-calibre or large-calibre gunnery, 
torpedo, bombing, and missile (including 2.75-inch rockets) 
activities during training, year-round. The boundary of this 
mitigation area is conterminous with the boundary of the portion of 
the Channel Islands NMS that is within the HSTT Study Area, and 
overlaps the extensive coastal gray whale migration BIA. The Channel 
Islands NMS is considered a highly productive and diverse area of 
high-value habitat that is more typically free of anthropogenic 
stressors (because many activities are prohibited or limited within 
the Sanctuary boundaries), and, therefore, limiting sonar and 
explosive activities in this area would be expected to reduce the 
likelihood that marine mammals feeding or resting in the area (which 
is more likely because of the higher value habitat) would be 
disrupted in a manner that would have adverse effects on their 
energy budgets and potentially impact reproduction or survival, or 
that marine mammals using the area would incur TTS or PTS. Activity 
limitations in this mitigation area are considered protection of 
generally higher quality habitat (because of the diversity of prey 
species and protected space, including acoustic habitat, that is 
generally freer from stressors) for the myriad marine mammal species 
that use it or may pass through the area, which could include any of 
the species identified as being present in the SOCAL portion of the 
HSTT Study Area. Though the gray whale migration area primarily 
consists of a relatively narrow coastal strip, some gray whales 
migrate through this area, either north or south, in all months of 
the year except August and September.
    San Diego Arc, San Nicolas Island, and Santa Monica/Long Beach 
Mitigation Areas: From June 1 through October 31, the Navy will not 
conduct more than 200 hours of surface ship hull-mounted MFAS in 
these combined areas during training or testing, and will limit 
explosive use in the three areas as described in Table 66 below. The 
San Diego Arc Mitigation Area is conterminous with the entirety of a 
blue whale feeding BIA and the other two mitigation areas are 
conterminous with the portions of two blue whale feeding BIAs that 
overlap the HSTT Study Area. One blue whale feeding BIA in SOCAL is 
not protected by a mitigation area (Tanner-Cortes Banks) because it 
would be impracticable due to the significant importance of the area 
for Navy testing and training (described in detail in the HSTT FEIS/
OEIS). All of these mitigation areas overlap the gray whale 
migratory route. Reducing harassing exposures (behavioral 
disturbance or hearing impairment) of marine mammals to sonar and 
explosives in feeding areas, even when the animals have demonstrated 
some tolerance for disturbance when in a feeding state, is expected 
to reduce the likelihood that feeding would be interrupted to a 
degree that energetic reserves might be affected in a manner that 
could reduce survivorship or reproductive success. This mitigation 
area will also partially overlap with an important migration area 
for gray whales.
    Blue whale (June-October), Gray Whale (November-March), and Fin 
Whale (November-May) Awareness Notification Message Area: The Navy 
will issue a seasonal awareness notification message that will alert 
ships and aircraft in the area of the possible presence of whales 
and instruct them to remain vigilant to the presence of large whales 
that, when seasonally concentrated (like blue whales, gray whales, 
or fin whales) may become vulnerable to vessel strikes. The message 
is issued to all Navy vessels in SOCAL in the indicated time 
periods. This message is will further increase the vigilance of Navy 
Lookouts in a place and time where blue, gray, and fin whale density 
is high, which will further reduce the chance that one of these 
species (or other large whale) may be struck.
    Information on the mitigation measures that the Navy will 
implement within mitigation areas is provided in Tables 65 and 66. 
The mitigation applies year-round unless specified otherwise in the 
tables.

Mitigation Areas for the Hawaii Range Complex (HRC)

    Mitigation areas for the HRC are described in Table 65 below. 
The location of each mitigation area is depicted in Figures 1 and 2 
above and may also be found in Chapter 5 of the 2018 HSTT FEIS/OEIS.

    Table 65--Mitigation Areas for Marine Mammals in the Hawaii Range
                                 Complex
------------------------------------------------------------------------
                       Mitigation area description
-------------------------------------------------------------------------
Stressor or Activity:
    <bullet> Sonar.
    <bullet> Explosives.
    <bullet> Vessel strikes.
Mitigation Area Requirements:
<bullet> Hawaii Island Mitigation Area (year-round):
    --Navy personnel must not conduct more than 300 hours of MF1 surface
     ship hull-mounted mid-frequency active sonar or 20 hours of MF4
     dipping sonar, or use explosives that could potentially result in
     takes of marine mammals during training and testing. Should
     national security require conduct of more than 300 hours of MF1
     surface ship hull-mounted mid-frequency active sonar or 20 hours of
     MF4 dipping sonar, or use of explosives that could potentially
     result in the take of marine mammals during training or testing,
     Naval units must obtain permission from the appropriate designated
     Command authority prior to commencement of the activity. Navy
     personnel must provide NMFS with advance notification and include
     the information (e.g., sonar hours or explosives usage) in its
     annual activity reports submitted to NMFS.
<bullet> 4-Islands Region Mitigation Area (November 15-April 15 for
 active sonar; year-round for explosives):
    --Navy personnel must not use MF1 surface ship hull-mounted mid-
     frequency active sonar or explosives that could potentially result
     in takes of marine mammals during training and testing. Should
     national security require use of MF1 surface ship hull-mounted mid-
     frequency active sonar or explosives that could potentially result
     in the take of marine mammals during training or testing, Naval
     units must obtain permission from the appropriate designated
     Command authority prior to commencement of the activity. Navy
     personnel must provide NMFS with advance notification and include
     the information (e.g., sonar hours or explosives usage) in its
     annual activity reports submitted to NMFS.
<bullet> Humpback Whale Special Reporting Areas (December 15-April 15):
    --Navy personnel must report the total hours of surface ship hull-
     mounted mid-frequency active sonar used in the special reporting
     areas in its annual training and testing activity reports submitted
     to NMFS.
<bullet> Humpback Whale Awareness Notification Message Area (November-
 April):
    --Navy personnel must issue a seasonal awareness notification
     message to alert ships and aircraft operating in the area to the
     possible presence of concentrations of large whales, including
     humpback whales.
    --To maintain safety of navigation and to avoid interactions with
     large whales during transits, Navy personnel must instruct vessels
     to remain vigilant to the presence of large whale species
     (including humpback whales), that when concentrated seasonally, may
     become vulnerable to vessel strikes.
    --Platforms must use the information from the awareness notification
     message to assist their visual observation of applicable mitigation
     zones during training and testing activities and to aid in the
     implementation of procedural mitigation.
------------------------------------------------------------------------


[[Page 66972]]

Mitigation Areas for the SOCAL Portion of the Study Area

    Mitigation areas for the SOCAL portion of the Study Area are 
described in Table 66 below. The location of each mitigation area is 
depicted in Figures 3 and 4 above and may also be found in Chapter 5 
of in the 2018 HSTT FEIS/OEIS.

Table 66--Mitigation Areas for Marine Mammals in the Southern California
                        Portion of the Study Area
------------------------------------------------------------------------
                       Mitigation area description
-------------------------------------------------------------------------
Stressor or Activity
    <bullet> Sonar.
    <bullet> Explosives.
    <bullet> Vessel strikes.
Mitigation Area Requirements:
<bullet> San Diego Arc, San Nicolas Island, and Santa Monica/Long Beach
 Mitigation Areas (June 1-October 31):
    --Navy personnel must not conduct more than a total of 200 hours of
     MF1 surface ship hull-mounted mid-frequency active sonar in the
     combined areas, excluding normal maintenance and systems checks,
     during training and testing. Should national security require
     conduct of more than 200 hours of MF1 surface ship hull-mounted mid-
     frequency active sonar in the combined areas during training and
     testing (excluding normal maintenance and systems checks), naval
     units must obtain permission from the appropriate designated
     Command authority prior to commencement of the activity. Navy
     personnel must provide NMFS with advance notification and include
     the information (e.g., sonar hours) in its annual activity reports
     submitted to NMFS.
    --Within the San Diego Arc Mitigation Area, Navy personnel must not
     use explosives that could potentially result in the take of marine
     mammals during large-caliber gunnery, torpedo, bombing, and missile
     (including 2.75'' rockets) activities during training and testing.
     Should national security require use of explosives that could
     potentially result in the take of marine mammals during large-
     caliber gunnery, torpedo, bombing, and missile (including 2.75''
     rockets) activities during training or testing, naval units must
     obtain permission from the appropriate designated Command authority
     prior to commencement of the activity. Navy personnel must provide
     NMFS with advance notification and include the information (e.g.,
     explosives usage) in its annual activity reports submitted to NMFS.
    --Within the San Nicolas Island Mitigation Area, Navy personnel must
     not use explosives that could potentially result in the take of
     marine mammals during mine warfare, large-caliber gunnery, torpedo,
     bombing, and missile (including 2.75'' rockets) activities during
     training. Should national security require use of explosives that
     could potentially result in the take of marine mammals during mine
     warfare, large-caliber gunnery, torpedo, bombing, and missile
     (including 2.75'' rockets) activities during training, Naval units
     must obtain permission from the appropriate designated Command
     authority prior to commencement of the activity. The Navy must
     provide NMFS with advance notification and include the information
     (e.g., explosives usage) in its annual activity reports submitted
     to NMFS.
    --Within the Santa Monica/Long Beach Mitigation Area, Navy personnel
     must not use explosives that could potentially result in the take
     of marine mammals during mine warfare, large-caliber gunnery,
     torpedo, bombing, and missile (including 2.75'' rockets) activities
     during training and testing. Should national security require use
     of explosives that could potentially result in the take of marine
     mammals during mine warfare, large-caliber gunnery, torpedo,
     bombing, and missile (including 2.75'' rockets) activities during
     training or testing, Naval units must obtain permission from the
     appropriate designated Command authority prior to commencement of
     the activity. Navy must provide NMFS with advance notification and
     include the information (e.g., explosives usage) in its annual
     activity reports submitted to NMFS.
<bullet> Santa Barbara Island Mitigation Area (year-round):
    --Navy personnel must not use MF1 surface ship hull-mounted mid-
     frequency active sonar during training or testing, or explosives
     that could potentially result in the take of marine mammals during
     medium-caliber or large-caliber gunnery, torpedo, bombing, and
     missile (including 2.75'' rockets) activities during training.
     Should national security require use of MF1 surface ship hull-
     mounted mid-frequency active sonar during training or testing, or
     explosives that could potentially result in the take of marine
     mammals during medium-caliber or large-caliber gunnery, torpedo,
     bombing, and missile (including 2.75'' rockets) activities during
     training, Naval units must obtain permission from the appropriate
     designated Command authority prior to commencement of the activity.
     Navy personnel must provide NMFS with advance notification and
     include the information (e.g., sonar hours or explosives usage) in
     its annual activity reports submitted to NMFS.
<bullet> Blue Whale (June-October), Gray Whale (November-March), and Fin
 Whale (November-May) Awareness Notification Message Areas:
    --Navy personnel must issue a seasonal awareness notification
     message to alert ships and aircraft operating in the area to the
     possible presence of concentrations of large whales, including blue
     whales, gray whales, or fin whales.
    --To maintain safety of navigation and to avoid interactions with
     large whales during transits, Navy personnel must instruct vessels
     to remain vigilant to the presence of large whale species, that
     when concentrated seasonally, may become vulnerable to vessel
     strikes.
    --Platforms must use the information from the awareness notification
     messages to assist their visual observation of applicable
     mitigation zones during training and testing activities and to aid
     in the implementation of procedural mitigation.
------------------------------------------------------------------------

Summary of Mitigation

    The Navy's mitigation measures are summarized in Tables 67 
(Procedural Mitigation) and 68 (Mitigation Areas).

Summary of Procedural Mitigation

               Table 67--Summary of Procedural Mitigation
------------------------------------------------------------------------
                                         Mitigation zone sizes and other
          Stressor or activity                     requirements
------------------------------------------------------------------------
Environmental Awareness and Education..  <bullet> Afloat Environmental
                                          Compliance Training program
                                          for applicable personnel.
Active Sonar...........................  Depending on sonar source:
                                         <bullet> 1,000 yd power down,
                                          500 yd power down, and 200 yd
                                          shut down
                                         <bullet> 200 yd shut down.
Air Guns...............................  <bullet> 150 yd.
Pile Driving...........................  <bullet> 100 yd.
Weapons Firing Noise...................  <bullet> 30[deg] on either side
                                          of the firing line out to 70
                                          yd.
Explosive Sonobuoys....................  <bullet> 600 yd.

[[Page 66973]]

 
Explosive Torpedoes....................  <bullet> 2,100 yd.
Explosive Medium-Caliber and Large-      <bullet> 1,000 y. (large-
 Caliber Projectiles.                     caliber projectiles).
                                         <bullet> 600 yd (medium-caliber
                                          projectiles during surface-to-
                                          surface activities).
                                         <bullet> 200 yd (medium-caliber
                                          projectiles during air-to-
                                          surface activities).
Explosive Missiles and Rockets.........  <bullet> 2,000 yd (21-500 lb.
                                          net explosive weight).
                                         <bullet> 900 yd (0.6-20 lb. net
                                          explosive weight).
Explosive Bombs........................  <bullet> 2,500 yd.
Sinking Exercises......................  <bullet> 2.5 nmi.
Explosive Mine Countermeasure and        <bullet> 2,100 yd (6-650 lb net
 Neutralization Activities.               explosive weight).
                                         <bullet> 600 yd (0.1-5 lb net
                                          explosive weight).
Explosive Mine Neutralization            <bullet> 1,000 yd (21-60 lb net
 Activities Involving Navy Divers.        explosive weight for positive
                                          control charges and charges
                                          using time-delay fuses).
                                         <bullet> 500 yd (0.1-20 lb net
                                          explosive weight for positive
                                          control charges).
Underwater Demolition Multiple Charge--  <bullet> 700 yd.
 Mat Weave and Obstacle Loading.
Maritime Security Operations--Anti-      <bullet> 200 yd.
 Swimmer Grenades.
Vessel Movement........................  <bullet> 500 yd (whales).
                                         <bullet> 200 yd (other marine
                                          mammals).
Towed In-Water Devices.................  <bullet> 250 yd (marine
                                          mammals).
Small-, Medium-, and Large-Caliber Non-  <bullet> 200 yd.
 Explosive Practice Munitions.
Non-Explosive Missiles and Rockets.....  <bullet> 900 yd.
Non-Explosive Bombs and Mine Shapes....  <bullet> 1,000 yd.
------------------------------------------------------------------------

Summary of Mitigation Areas

        Table 68--Summary of Mitigation Areas for Marine Mammals
------------------------------------------------------------------------
                 Summary of mitigation area requirements
-------------------------------------------------------------------------
Mitigation Areas for Shallow-water Coral Reefs and Precious Coral Beds
 (year-round)
    <bullet> The Navy must not conduct precision anchoring (except in
     designated anchorages), explosive or non-explosive mine
     countermeasure and neutralization activities, explosive or non-
     explosive mine neutralization activities involving Navy divers,
     explosive or non-explosive small-, medium-, and large-caliber
     gunnery activities using a surface target, explosive or non-
     explosive missile and rocket activities using a surface target, and
     explosive or non-explosive bombing or mine laying activities
     (except in designated locations).
    <bullet> The Navy must not place mine shapes, anchors, or mooring
     devices on the seafloor (except in designated locations).
Hawaii Island Mitigation Area (year-round)
    <bullet> Navy personnel must not conduct more than 300 hours of MF1
     surface ship hull-mounted mid-frequency active sonar or 20 hours of
     MF4 dipping sonar, or use explosives that could potentially result
     in takes of marine mammals during training and testing.\1\
4-Islands Region Mitigation Area (November 15-April 15 for active sonar;
 year-round for explosives)
    <bullet> Navy personnel must not use MF1 surface ship hull-mounted
     mid-frequency active sonar or explosives that could potentially
     result in takes of marine mammals during training and testing.\1\
Humpback Whale Special Reporting Areas (December 15-April 15)
    <bullet> Navy personnel must report the total hours of surface ship
     hull-mounted mid-frequency active sonar used in in the special
     reporting areas in its annual training and testing activity reports
     submitted to NMFS.
San Diego Arc, San Nicolas Island, and Santa Monica/Long Beach
 Mitigation Areas (June 1-October 31)
    <bullet> Navy personnel must not conduct more than a total of 200
     hours of MF1 surface ship hull-mounted mid-frequency active sonar
     in the combined areas, excluding normal maintenance and systems
     checks, during training and testing.\1\
    <bullet> Within the San Diego Arc Mitigation Area, Navy personnel
     must not use explosives that could potentially result in the take
     of marine mammals during large-caliber gunnery, torpedo, bombing,
     and missile (including 2.75'' rockets) activities during training
     and testing.\1\
    <bullet> Within the San Nicolas Island Mitigation Area, Navy
     personnel must not use explosives that could potentially result in
     the take of marine mammals during mine warfare, large-caliber
     gunnery, torpedo, bombing, and missile (including 2.75'' rockets)
     activities during training.\1\
    <bullet> Within the Santa Monica/Long Beach Mitigation Area, Navy
     personnel must not use explosives that could potentially result in
     the take of marine mammals during mine warfare, large-caliber
     gunnery, torpedo, bombing, and missile (including 2.75'' rockets)
     activities during training and testing.\1\
Santa Barbara Island Mitigation Area (year-round)
    <bullet> Navy personnel must not use MF1 surface ship hull-mounted
     mid-frequency active sonar during training and testing, or
     explosives that could potentially result in the take of marine
     mammals during medium-caliber or large-caliber gunnery, torpedo,
     bombing, and missile (including 2.75'' rockets) activities during
     training.\1\
Awareness Notification Message Areas (seasonal according to species)
    <bullet> Navy personnel must issue awareness notification messages
     to alert ships and aircraft to the possible presence of humpback
     whales (November-April), blue whales (June-October), gray whales
     (November-March), or fin whales (November-May).
------------------------------------------------------------------------
\1\ If Naval units need to conduct more than the specified amount of
  training or testing, they will obtain permission from the appropriate
  designated Command authority prior to commencement of the activity.
  The Navy will provide NMFS with advance notification and include the
  information in its annual activity reports submitted to NMFS.


[[Page 66974]]

Mitigation Conclusions

    NMFS has carefully evaluated the Navy's mitigation measures--
many of which were developed with NMFS' input during the previous 
phases of Navy training and testing authorizations, or during the 
development of the proposed or final rule for these HSTT Phase 3 
activities. NMFS and the Navy also considered a broad range of other 
measures (i.e., the measures considered but eliminated, as discussed 
in the HSTT FEIS/OEIS, which reflect many of the comments that have 
arisen via public input in past years) to ensure that NMFS 
prescribes the means of effecting the least practicable adverse 
impact on the affected marine mammal species and stocks and their 
habitat. In particular for this rule, we carefully and thoroughly 
evaluated those additional measures that were put in place in 2015 
as a result of the settlement agreement in Conservation Council for 
Hawaii v. National Marine Fisheries Service. Our evaluation of 
mitigation measures included consideration of the following factors 
in relation to one another: The manner in which, and the degree to 
which, the successful implementation of the mitigation measures is 
expected to reduce the likelihood and/or magnitude of adverse 
impacts to marine mammal species and stocks and their habitat; the 
proven or likely efficacy of the measures; and the practicability of 
the measures for applicant implementation, including consideration 
of personnel safety, practicality of implementation, and impact on 
the effectiveness of the military readiness activity. Ultimately, 
the Navy adopted all mitigation measures that are practicable by, 
among other things, not jeopardizing its mission and Title 10 
responsibilities. A comprehensive assessment by Navy leadership of 
the final, entire list of mitigation measures concluded that the 
inclusion of any further mitigation beyond those measures identified 
here in the final rule would be entirely impracticable. NMFS 
independently reviewed the Navy's practicability determinations for 
specific mitigation areas and concurs with the Navy's analysis.
    Based on our evaluation of the Navy's planned measures, as well 
as other measures considered by the Navy and NMFS, NMFS has 
determined that the mitigation measures included in this rule are 
appropriate means of effecting the least practicable adverse impacts 
on marine mammals species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of 
similar significance, considering specifically personnel safety, 
practicality of implementation, and impact on the effectiveness of 
the military readiness activity.
    Additionally, as described in more detail below, the final rule 
includes an adaptive management provision, which ensures that 
mitigation is regularly assessed and provides a mechanism to improve 
the mitigation, based on the factors above, through modification as 
appropriate.

Monitoring

    Section 101(a)(5)(A) of the MMPA states that in order to 
authorize incidental take for an activity, NMFS must set forth 
``requirements pertaining to the monitoring and reporting of such 
taking.'' The MMPA implementing regulations at 50 CFR 216.104(a)(13) 
indicate that requests for incidental take authorizations must 
include the suggested means of accomplishing the necessary 
monitoring and reporting that will result in increased knowledge of 
the species and of the level of taking or impacts on populations of 
marine mammals that are expected to be present.
    Although the Navy has been conducting research and monitoring in 
the HSTT Study Area for over 20 years, it developed a formal marine 
species monitoring program in support of the MMPA and ESA 
authorizations for the Hawaii and Southern California range 
complexes in 2009. This robust program has resulted in hundreds of 
technical reports and publications on marine mammals that have 
informed Navy and NMFS analyses in environmental planning documents, 
rules, and Biological Opinions. The reports are made available to 
the public on the Navy's marine species monitoring website 
(www.navymarinespeciesmonitoring.us) and the data on the Ocean 
Biogeographic Information System Spatial Ecological Analysis of 
Megavertebrate Populations (OBIS-SEAMAP) (www.seamap.env.duke.edu).
    The Navy will continue collecting monitoring data to inform our 
understanding of the occurrence of marine mammals in the HSTT Study 
Area; the likely exposure of marine mammals to stressors of concern 
in the HSTT Study Area; the response of marine mammals to exposures 
to stressors; the consequences of a particular marine mammal 
response to their individual fitness and, ultimately, populations; 
and the effectiveness of implemented mitigation measures. Taken 
together, mitigation and monitoring comprise the Navy's integrated 
approach for reducing environmental impacts from the specified 
activities. The Navy's overall monitoring approach seeks to leverage 
and build on existing research efforts whenever possible.
    As agreed upon between the Navy and NMFS, monitoring measures 
presented here, as well as the mitigation measures described above, 
focus on the protection and management of potentially affected 
marine mammals. A well-designed monitoring program can provide 
important feedback for validating assumptions made in analyses and 
allow for adaptive management of marine resources. Monitoring is 
required under the MMPA, and details of the monitoring program for 
the specified activities have been developed through coordination 
between NMFS and the Navy through the regulatory process for 
previous Navy at-sea training and testing actions.

Integrated Comprehensive Monitoring Program (ICMP)

    The Navy's ICMP is intended to coordinate marine species 
monitoring efforts across all regions and to allocate the most 
appropriate level and type of effort for each range complex based on 
a set of standardized objectives, and in acknowledgement of regional 
expertise and resource availability. The ICMP is designed to be 
flexible, scalable, and adaptable through the adaptive management 
and strategic planning processes to periodically assess progress and 
reevaluate objectives. This process includes conducting an annual 
adaptive management review meeting, at which the Navy and NMFS 
jointly consider the prior-year goals, monitoring results, and 
related scientific advances to determine if monitoring plan 
modifications are warranted to more effectively address program 
goals. Although the ICMP does not specify actual monitoring field 
work or individual projects, it does establish a matrix of goals and 
objectives that have been developed in coordination with NMFS. As 
the ICMP is implemented through the Strategic Planning Process, 
detailed and specific studies will be developed which support the 
Navy's and NMFS top-level monitoring goals. In essence, the ICMP 
directs that monitoring activities relating to the effects of Navy 
training and testing activities on marine species should be designed 
to contribute towards one or more of the following top-level goals:

    [ssquf] An increase in our understanding of the likely 
occurrence of marine mammals and/or ESA-listed marine species in the 
vicinity of the action (i.e., presence, abundance, distribution, 
and/or density of species);
    [ssquf] An increase in our understanding of the nature, scope, 
or context of the likely exposure of marine mammals and/or ESA-
listed species to any of the potential stressor(s) associated with 
the action (e.g., sound, explosive detonation, or military expended 
materials) through better understanding of one or more of the 
following: (1) The action and the environment in which it occurs 
(e.g., sound source characterization, propagation, and ambient noise 
levels); (2) the affected species (e.g., life history or dive 
patterns); (3) the likely co-occurrence of marine mammals and/or 
ESA-listed marine species with the action (in whole or part); and/or 
(4) the likely biological or behavioral context of exposure to the 
stressor for the marine mammal and/or ESA-listed marine species 
(e.g., age class of exposed animals or known pupping, calving or 
feeding areas);
    [ssquf] An increase in our understanding of how individual 
marine mammals or ESA-listed marine species respond (behaviorally or 
physiologically) to the specific stressors associated with the 
action (in specific contexts, where possible, e.g., at what distance 
or received level);
    [ssquf] An increase in our understanding of how anticipated 
individual responses, to individual stressors or anticipated 
combinations of stressors, may impact either: (1) The long-term 
fitness and survival of an individual or (2) the population, 
species, or stock (e.g., through effects on annual rates of 
recruitment or survival);
    [ssquf] An increase in our understanding of the effectiveness of 
mitigation and monitoring measures;
    [ssquf] A better understanding and record of the manner in which 
the authorized entity complies with the incidental take regulations 
and LOAs and the ESA Incidental Take Statement;
    [ssquf] An increase in the probability of detecting marine 
mammals (through

[[Page 66975]]

improved technology or methods), both specifically within the 
mitigation zone (thus allowing for more effective implementation of 
the mitigation) and in general, to better achieve the above goals; 
and
    [ssquf] Ensuring that adverse impact of activities remains at 
the least practicable level.

Strategic Planning Process for Marine Species Monitoring

    The Navy also developed the Strategic Planning Process for Marine 
Species Monitoring, which establishes the guidelines and processes 
necessary to develop, evaluate, and fund individual projects based on 
objective scientific study questions. The process uses an underlying 
framework designed around intermediate scientific objectives and a 
conceptual framework incorporating a progression of knowledge spanning 
occurrence, exposure, response, and consequence. The Strategic Planning 
Process for Marine Species Monitoring is used to set overarching 
intermediate scientific objectives; develop individual monitoring 
project concepts; identify potential species of interest at a regional 
scale; evaluate, prioritize and select specific monitoring projects to 
fund or continue supporting for a given fiscal year; execute and manage 
selected monitoring projects; and report and evaluate progress and 
results. This process addresses relative investments to different range 
complexes based on goals across all range complexes, and monitoring 
would leverage multiple techniques for data acquisition and analysis 
whenever possible. The Strategic Planning Process for Marine Species 
Monitoring is also available online (http://www.navymarinespeciesmonitoring.us/).

Past and Current Monitoring in the HSTT Study Area

    The monitoring program has undergone significant changes since the 
first rules were issued for HRC and SOCAL in 2009, which highlights its 
evolution through the process of adaptive management. The monitoring 
program developed for the first cycle of environmental compliance 
documents (e.g., U.S. Department of the Navy, 2008) utilized effort-
based compliance metrics that were somewhat limiting. Through adaptive 
management discussions, the Navy designed and conducted monitoring 
studies according to scientific objectives, thereby eliminating basing 
requirements upon metrics of level-of-effort. Furthermore, refinements 
of scientific objective have continued through the latest permit cycle 
through 2018.
    Progress has also been made on the monitoring program's conceptual 
framework categories from the Scientific Advisory Group for Navy Marine 
Species Monitoring (U.S. Department of the Navy, 2011e), ranging from 
occurrence of animals to their exposure, response, and population 
consequences. Lessons-learned with monitoring in the first two MMPA 
rulemaking periods in HRC and SOCAL suggested that ``layering'' 
multiple components of monitoring simultaneously provides a way to 
leverage an increase in return of the progress toward answering 
scientific monitoring questions.
    Specific monitoring under the 2013-2018 regulations has included:

[ssquf] HRC

    [cir] Long-term Trends in Abundance of Marine Mammals at the 
Pacific Missile Range Facility (PMRF);
    [cir] Estimation of Received Levels of Mid-Frequency Active 
Sonar on Marine Mammals at PMRF;
    [cir] Behavioral Response of Marine Mammals to Navy Training and 
Testing at PMRF; and
    [cir] Navy Civilian Marine Mammal Observers on MFAS Ships in 
Offshore Waters of HRC.
[ssquf] SOCAL

    [cir] Blue and Fin Whale Satellite Tagging;
    [cir] Cuvier's Beaked Whale Impact Assessment at the Southern 
California Offshore Antisubmarine Warfare Range (SOAR);
    [cir] Cuvier's Beaked Whale, Blue Whale, and Fin Whale Impact 
Assessments at Non-Instrumented Range Locations in SOCAL; and
    [cir] Marine Mammal Sightings during California Cooperative 
Oceanic Fisheries Investigation (CalCOFI) Cruises.

    Numerous publications, dissertations, and conference presentations 
have resulted from research conducted under the Navy's marine species 
monitoring program (https://www.navymarinespeciesmonitoring.us/reading-room/publications/), resulting in a significant contribution to the 
body of marine mammal science. Publications on occurrence, 
distribution, and density have fed the modeling input, and publications 
on exposure and response have informed Navy and NMFS analyses of 
behavioral response and consideration of mitigation measures.
    Furthermore, collaboration between the monitoring program and the 
Navy's research and development (e.g., the Office of Naval Research) 
and demonstration-validation (e.g., Living Marine Resources) programs 
has been strengthened, leading to research tools and products that have 
already transitioned to the monitoring program. These include Marine 
Mammal Monitoring on Ranges (M3R), controlled exposure experiment 
behavioral response studies (CEE BRS), acoustic sea glider surveys, and 
global positioning system-enabled satellite tags. Recent progress has 
been made with better integration of monitoring across all Navy at-sea 
study areas, including study areas in the Pacific and the Atlantic 
Oceans, and various testing ranges. Publications from the Living Marine 
Resources and Office of Naval Research programs have also resulted in 
significant contributions to hearing, acoustic criteria used in effects 
modeling, exposure, and response, as well as developing tools to assess 
biological significance (e.g., population-level consequences).
    NMFS and the Navy also consider data collected during procedural 
mitigations as monitoring. Data are collected by shipboard personnel on 
hours spent training, hours of observation, hours of sonar, and marine 
mammals observed within the mitigation zone during Major Training 
Exercises when mitigations are implemented. These data are provided to 
NMFS in both classified and unclassified annual exercise reports.
    NMFS has received multiple years' worth of annual exercise and 
monitoring reports addressing active sonar use and explosive 
detonations within the HSTT Study Area and other Navy range complexes. 
The data and information contained in these reports have been 
considered in developing mitigation and monitoring measures for the 
training and testing activities within the HSTT Study Area. The Navy's 
annual exercise and monitoring reports may be viewed at: http://www.nmfs.noaa.gov/pr/permits/incidental/military.htm and http://www.navymarinespeciesmonitoring.us.
    The Navy has been funding various marine mammal studies and 
research within the HSTT Study Area for the past 20 years. Under 
permitting from NMFS starting in 2009, this effort has transitioned 
from a specific metric based approach, to a broader new research only 
approach (e.g., set number of visual surveys, specific number of 
passive acoustic recording devices, etc.), and more recently since 2014 
a more regional (Hawaii or Southern California) species-specific study 
question design (e.g., what is distribution of species A within the 
HSTT Study Area, what is response of species B to Navy activities, 
etc.).
    In adaptive management consultation with NMFS, some variation of 
these ongoing studies or planned new studies will continue within the 
HSTT Study Area for either the duration of these new regulations, or 
for a set period as specified in a given project's scope. Some projects 
may only require one or two years of field effort. Other projects

[[Page 66976]]

could entail multi-year field efforts (two to five years). For 
instance, in the SOCAL portion of the HSTT Study Area, the Navy has 
funded development and application of new passive acoustic technology 
since the early 2000's for detecting Cuvier's beaked whales. This also 
includes ongoing effort to further identify and update population 
demographics for Cuvier's beaked whales (re-sighting rates, population 
growth, calving rates, movements, etc.) specific to Navy training and 
testing areas, as well as responses to Navy activity. Variations of 
these Cuvier's beaked whale monitoring studies will likely continue 
under future authorizations. The Navy's marine species monitoring web 
portal provides details on past and current monitoring projects, 
including technical reports, publications, presentations, and access to 
available data, and can be found at: https://www.navymarinespeciesmonitoring.us/regions/pacific/current-projects/.
    The Navy's marine species monitoring program typically supports 6-
10 monitoring projects in the HSTT Study Area at any given time. 
Projects can be either major multi-year efforts, or one to two year 
special studies. The Navy's monitoring projects going into 2019 
include:

    [ssquf] Long-term Trends in Abundance of Marine Mammals at PMRF 
(Hawaii)--Analysis of long-term archive of hydrophone recordings 
from the instrumented range at PMRF to uncover long-term trends in 
the occurrence of marine mammals on the range, including minke 
whale, humpback whale, fin whale, Bryde's whale, and Blainville's 
beaked whale.
    [ssquf] Estimation of Received Levels of MFAS and an 
opportunistic Behavioral Response Study of Marine Mammals at PMRF 
(Hawaii)--Estimation of the received level of mid-frequency active 
sonar (MFAS) of marine mammals (including blackfish species, 
mysticetes, sperm whale, and beaked whales) near PMRF as well as 
their short-term behavioral responses. Analysts will perform 
acoustic propagation modeling from Navy platforms to localized 
animals. Animals may be localized either acoustically by the range 
hydrophones, or by a satellite tagging effort. The tagging component 
will also provide information on spatial movement and habitat-use 
patterns. Both received-level and behavioral response studies will 
be an opportunistic protocol performed during actual Navy training 
deploying MFAS.
    [ssquf] Humpback Whale Tagging at PMRF (Hawaii)--A combination 
of acoustic pinger and satellite tags will be applied to humpback 
whales to investigate the movement patterns, habitat use, and 
behavior of humpback whales (nearshore and offshore) of different 
age-sex classes on and off the instrumented range at PMRF. The tags 
will also enable enhanced validation of localization algorithms 
using the range hydrophones, as well as provide locations of animals 
when they are not vocalizing.
    [ssquf] Navy Civilian Marine Mammal Observers on guided missile 
destroyers (DDGs) (Hawaii and Southern California)--Visual survey 
for marine mammals will be performed by biologist observers embarked 
aboard Navy DDGs during training exercises involving deployment of 
MFAS. The acquired data will be incorporated in a long-term project 
investigating the mitigation effectiveness of Navy Lookouts that 
spans all Navy at-sea training ranges in both the Atlantic and 
Pacific oceans.
    [ssquf] Cuvier's Beaked Whale Impact Assessment at SOAR 
(Southern California)--The instrumented hydrophone range at the 
Navy's Southern California Antisubmarine Warfare Range (SOAR), 
combined with concurrent field efforts with satellite tagging and 
visual surveys will investigate key baseline population demographics 
and movement patterns for Cuvier's beaked whale. Short-term 
behavioral and/or vocal responses when Cuvier's beaked whales are 
exposed to sonar will also be investigated.
    [ssquf] Beaked Whale Occurrence In Southern California From 
Passive Acoustic Monitoring (Southern California)--This project has 
three field components. Bottom-moored passive acoustic devices will 
investigate the seasonality and spatial distribution of beaked whale 
species in Southern California including new deployments in Baja. 
Also, ocean profiling gliders outfitted with a high frequency 
acoustic recording system will perform a survey on a larger 
geographic scale and across a diverse range of habitats in Southern 
California to investigate the spatial distribution and occurrence of 
beaked whale species. Finally, passive acoustic data from towed 
arrays deployed during quarterly California Cooperative Oceanic 
Fisheries Investigations surveys will be analyzed for beaked whales 
across a large geographic scale.
    [ssquf] Guadalupe Fur Seal Population Census and Satellite 
Tracking (Southern California)--Satellite tagging as well as land-
based visual survey will investigate the habitat use by age-sex 
class of Guadalupe fur seals across both the Southern California 
Range Complex and Northwest Training and Testing study areas, as 
well as other areas including epipelagic waters.
    [ssquf] Blue and Fin Whale Satellite Tagging and Genetics 
(Southern California)--Satellite tagging of blue whales and fin 
whales at various locations off southern California occurred from 
2014-2017. The project investigated movement patterns, occurrence, 
and residence times of blue and fin whales within Navy training and 
testing areas along the U.S. West Coast as compared to other areas 
visited by tagged whales outside of Navy training and testing areas. 
While field efforts for this project are complete, additional 
analysis will continue beyond 2018 and include peer-reviewed result 
publication.

    Additional scientific projects may have field efforts within Hawaii 
and Southern California under separate Navy funding from the Navy's two 
marine species research programs, the Office of Naval Research Marine 
Mammals and Biology Program and the Living Marine Resources Program. 
The periodicity of these research projects are more variable than the 
Navy's compliance monitoring described above.

Adaptive Management

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

Reporting

    In order to issue an incidental take authorization for an activity, 
section

[[Page 66977]]

101(a)(5)(A) of the MMPA states that NMFS must set forth ``requirements 
pertaining to the monitoring and reporting of such taking.'' Effective 
reporting is critical both to compliance as well as ensuring that the 
most value is obtained from the required monitoring. Reports from 
individual monitoring events, results of analyses, publications, and 
periodic progress reports for specific monitoring projects would be 
posted to the Navy's Marine Species Monitoring web portal: http://www.navymarinespeciesmonitoring.us. Currently, there are several 
different reporting requirements pursuant to these regulations:

Notification of Injured, Live Stranded or Dead Marine Mammals

    The Navy will consult the Notification and Reporting Plan, which 
sets out notification, reporting, and other requirements when injured, 
live stranded, or dead marine mammals are detected. The Notification 
and Reporting Plan is available for review at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.

Annual HSTT Monitoring Report

    The Navy will submit an annual report to NMFS of the HSTT 
monitoring describing the implementation and results from the previous 
calendar year. Data collection methods will be standardized across 
range complexes and HSTT Study Area to allow for comparison in 
different geographic locations. The draft of the annual monitoring 
report will be submitted either three months after the calendar year, 
or three months after the conclusion of the monitoring year to be 
determined by the Adaptive Management process. Such a report would 
describe progress of knowledge made with respect to intermediate 
scientific objectives within the HSTT Study Area associated with the 
Integrated Comprehensive Monitoring Program. Similar study questions 
will be treated together so that summaries can be provided for each 
topic area. The report need not include analyses and content that do 
not provide direct assessment of cumulative progress on the monitoring 
plan study questions. NMFS will submit comments on the draft monitoring 
report, if any, within three months of receipt. The report will be 
considered final after the Navy has addressed NMFS' comments, or three 
months after the submittal of the draft if NMFS does not have comments.
    As an alternative, the Navy may submit a multi-Range Complex annual 
Monitoring Plan report to fulfill this requirement. Such a report will 
describe progress of knowledge made with respect to monitoring study 
questions across multiple Navy ranges associated with the ICMP. Similar 
study questions will be treated together so that progress on each topic 
will be summarized across multiple Navy ranges. The report need not 
include analyses and content that does not provide direct assessment of 
cumulative progress on the monitoring study question. This will 
continue to allow Navy to provide a cohesive monitoring report covering 
multiple ranges (as per ICMP goals), rather than entirely separate 
reports for the HSTT, Gulf of Alaska, Mariana Islands, and the 
Northwest Study Areas.

Annual HSTT Training Exercise Report and Testing Activity Report

    Each year, the Navy will submit two preliminary reports (Quick Look 
Reports) to NMFS detailing the status of authorized sound sources 
within 21 days after the anniversary of the date of issuance of the 
LOAs. Each year, the Navy will also submit detailed reports to NMFS 
within three months after the one-year anniversary of the date of 
issuance of the LOAs. The annual reports will contain information on 
MTEs, Sinking Exercise (SINKEX) events, and a summary of all sound 
sources used (total hours or quantity (per the LOA) of each bin of 
sonar or other non-impulsive source; total annual number of each type 
of explosive exercises; and total annual expended/detonated rounds 
(missiles, bombs, sonobuoys, etc.) for each explosive bin). The report 
will also include the details regarding specific requirements 
associated with specific mitigation areas. The analysis in the detailed 
reports will be based on the accumulation of data from the current 
year's report and data collected from previous reports. Information 
included in the classified annual reports may be used to inform future 
adaptive management of activities within the HSTT Study Area.
    The Annual HSTT Training Exercise Report and Testing Activity Navy 
reports (classified or unclassified versions) can be consolidated with 
other exercise reports from other range complexes in the Pacific Ocean 
for a single Pacific Exercise Report, if desired. Specific sub-
reporting in these annual reports include:

    [ssquf] Humpback Whale Special Reporting Area (December 15-April 
15): The Navy will report the total hours of operation of surface 
ship hull-mounted mid-frequency active sonar used in the special 
reporting area; and
    [ssquf] HSTT Mitigation Areas (see Chapter 11 of the Navy's 
rulemaking/LOA application): The Navy will report any use of surface 
ship hull-mounted mid-frequency active sonar that occurred as 
specifically described in these areas.
    [ssquf] Major Training Exercises Notification

    The Navy shall submit an electronic report to NMFS within fifteen 
calendar days after the completion of any major training exercise 
indicating: Location of the exercise; beginning and end dates of the 
exercise; and type of exercise.

Other Reporting and Coordination

    The Navy will continue to report and coordinate with NMFS for the 
following:

    [ssquf] Annual marine species monitoring technical review 
meetings with researchers and the Marine Mammal Commission 
(currently, every two years a joint Pacific-Atlantic meeting is 
held); and
    [ssquf] Annual Adaptive Management meetings with the Marine 
Mammal Commission (recently modified to occur in conjunction with 
the annual monitoring technical review meeting).

Analysis and Negligible Impact Determination

Negligible Impact Analysis

Introduction
    NMFS has defined negligible impact as ``an impact resulting from 
the specified activity that cannot be reasonably expected to, and is 
not reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through mortality, serious injury, and Level A or Level B 
harassment (as presented in Tables 41 and 42), NMFS considers other 
factors, such as the likely nature of any responses (e.g., intensity, 
duration), the context of any responses (e.g., critical reproductive 
time or location, migration), as well as effects on habitat, and the 
likely effectiveness of the mitigation. We also assess the number, 
intensity, and context of estimated takes by evaluating this 
information relative to population status. Consistent with the 1989 
preamble for NMFS' implementing regulations (54 FR 40338; September 29, 
1989), the impacts from other past and ongoing anthropogenic activities 
are incorporated into this analysis via their

[[Page 66978]]

impacts on the environmental baseline (e.g., as reflected in the 
regulatory status of the species, population size and growth rate where 
known, other ongoing sources of human-caused mortality, ambient noise 
levels, and specific consideration of take by Level A harassment or 
serious injury or mortality (hereafter referred to as M/SI) previously 
authorized for other NMFS activities).
    In the Estimated Take of Marine Mammals section, we identified the 
subset of potential effects that would be expected to rise to the level 
of takes, and then identified the number of each of those mortality 
takes that we believe could occur or harassment takes that are likely 
to occur based on the methods described. The impact that any given take 
will have is dependent on many case-specific factors that need to be 
considered in the negligible impact analysis (e.g., the context of 
behavioral exposures such as duration or intensity of a disturbance, 
the health of impacted animals, the status of a species that incurs 
fitness-level impacts to individuals, etc.). Here we evaluate the 
likely impacts of the enumerated harassment takes that are proposed for 
authorization and anticipated to occur under this rule, in the context 
of the specific circumstances surrounding these predicted takes. We 
also include a specific assessment of serious injury or mortality takes 
that could occur, as well as consideration of the traits and statuses 
of the affected species and stocks. Last, we collectively evaluate this 
information, as well as other more taxa-specific information and 
mitigation measure effectiveness, in group-specific discussions that 
support our negligible impact conclusions for each stock.
Harassment
    The Navy's Specified Activities reflect representative levels/
ranges of training and testing activities, accounting for the natural 
fluctuation in training, testing, and deployment schedules. This 
approach is representative of how the Navy's activities are conducted 
over any given year over any given five-year period. Specifically, the 
Navy provided a range of levels for each activity/source type for a 
year--they used the maximum annual level to calculate annual takes, and 
they used the sum of three nominal years (average level) and two 
maximum years to calculate five-year takes for each source type. The 
Description of the Specified Activity section contains a more realistic 
annual representation of activities, but includes years of a higher 
maximum amount of training and testing to account for these 
fluctuations. There may be some flexibility in the exact number of 
hours, items, or detonations that may vary from year to year, but take 
totals would not exceed the five-year totals indicated in Tables 41 and 
42. We base our analysis and negligible impact determination (NID) on 
the maximum number of takes that would be reasonably expected to occur 
and are being authorized, although, as stated before, the number of 
takes are only a part of the analysis, which includes extensive 
qualitative consideration of other contextual factors that influence 
the degree of impact of the takes on the affected individuals. To avoid 
repetition, we provide some general analysis immediately below that 
applies to all the species listed in Tables 41 and 42, given that some 
of the anticipated effects of the Navy's training and testing 
activities on marine mammals are expected to be relatively similar in 
nature. However, below that, we break our analysis into species (and/or 
stock), or groups of species (and the associated stocks) where relevant 
similarities exist, to provide more specific information related to the 
anticipated effects on individuals of a specific stock or where there 
is information about the status or structure of any species that would 
lead to a differing assessment of the effects on the species or stock. 
Organizing our analysis by grouping species or stocks that share common 
traits or that will respond similarly to effects of the Navy's 
activities and then providing species- or stock-specific information 
allows us to avoid duplication while assuring that we have analyzed the 
effects of the specified activities on each affected species or stock.
    The Navy's harassment take request is based on its model and 
quantitative assessment of mitigation, which NMFS believes 
appropriately predicts that maximum amount of harassment that is likely 
to occur. In the discussions below, the ``acoustic analysis'' refers to 
the Navy's modeling results and quantitative assessment of mitigation. 
The model calculates sound energy propagation from sonar, other active 
acoustic sources, and explosives during naval activities; the sound or 
impulse received by animat dosimeters representing marine mammals 
distributed in the area around the modeled activity; and whether the 
sound or impulse energy received by a marine mammal exceeds the 
thresholds for effects. Assumptions in the Navy model intentionally err 
on the side of overestimation when there are unknowns. Naval activities 
are modeled as though they would occur regardless of proximity to 
marine mammals, meaning that no mitigation is considered (e.g., no 
power down or shut down) and without any avoidance of the activity by 
the animal. The final step of the quantitative analysis of acoustic 
effects, which occurs after the modeling, is to consider the 
implementation of mitigation and the possibility that marine mammals 
would avoid continued or repeated sound exposures. NMFS provided input 
to, independently reviewed, and concurred with the Navy on this process 
and the Navy's analysis, which is described in detail in Section 6 of 
the Navy's rulemaking/LOA application (https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities), was used to quantify harassment takes 
for this rule.
    Generally speaking, the Navy and NMFS anticipate more severe 
effects from takes resulting from exposure to higher received levels 
(though this is in no way a strictly linear relationship for behavioral 
effects throughout species, individuals, or circumstances) and less 
severe effects from takes resulting from exposure to lower received 
levels. However, there is also growing evidence of the importance of 
distance in predicting marine mammal behavioral response to sound--
i.e., sounds of a similar level emanating from a more distant source 
have been shown to be less likely to evoke a response of equal 
magnitude (DeRuiter 2012). The estimated number of Level A and Level B 
harassment takes does not equate to the number of individual animals 
the Navy expects to harass (which is lower), but rather to the 
instances of take (i.e., exposures above the Level A and Level B 
harassment threshold) that are anticipated to occur over the five-year 
period. These instances may represent either brief exposures (seconds 
or minutes) or, in some cases, longer durations of exposure within a 
day. Some individuals may experience multiple instances of take 
(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

[[Page 66979]]

likely taken at least once in a year. We look at this comparative 
metric to give us a relative sense of where a larger portion of a stock 
is being taken by Navy activities, where there is a higher likelihood 
that the same individuals are being taken across multiple days, and 
where that number of days might be higher or more likely sequential. In 
the ocean, the use of sonar and other active acoustic sources is often 
transient and is unlikely to repeatedly expose the same individual 
animals within a short period, for example within one specific 
exercise. However, for some individuals of some stocks repeated 
exposures across different activities could occur over the year, 
especially where events occur in generally the same area with more 
resident species. In short, for some stocks we expect that the total 
anticipated takes represent exposures of a smaller number of 
individuals of which some were exposed multiple times, but based on the 
nature of the Navy activities and the movement patterns of marine 
mammals, it is unlikely that individuals from most species or stocks 
would be taken over more than a few sequential days. This means that 
even where repeated takes of individuals are likely to occur, they are 
more likely to result from non-sequential exposures from different 
activities, and, even if sequential, individual animals are not 
predicted to be taken for more than several days in a row, at most. As 
described elsewhere, the nature of the majority of the exposures would 
be expected to be of a less severe nature and based on the numbers it 
is likely that any individual exposed multiple times is still only 
taken on a small percentage of the days of the year. The greater 
likelihood is that not every individual is taken, or perhaps a smaller 
subset is taken with a slightly higher average and larger variability 
of highs and lows, but still with no reason to think that any 
individuals would be taken a significant portion of the days of the 
year, much less that many of the days of disturbance would be 
sequential.
    Some of the lower level physiological stress responses (e.g., 
orientation or startle response, change in respiration, change in heart 
rate) discussed earlier would likely co-occur with the predicted 
harassments, although these responses are more difficult to detect and 
fewer data exist relating these responses to specific received levels 
of sound. Level B harassment takes, then, may have a stress-related 
physiological component as well; however, we would not expect the 
Navy's generally short-term, intermittent, and (typically in the case 
of sonar) transitory activities to create conditions of long-term, 
continuous noise leading to long-term physiological stress responses in 
marine mammals.
    The estimates calculated using the behavioral response function do 
not differentiate between the different types of behavioral responses 
that rise to the level of Level B harassments. As described in the 
Navy's application, the Navy identified (with NMFS' input) the types of 
behaviors that would be considered a take (moderate behavioral 
responses as characterized in Southall et al. (2007) (e.g., altered 
migration paths or dive profiles, interrupted nursing, breeding or 
feeding, or avoidance) that also would be expected to continue for the 
duration of an exposure). The Navy then compiled the available data 
indicating at what received levels and distances those responses have 
occurred, and used the indicated literature to build biphasic 
behavioral response curves that are used to predict how many instances 
of Level B behavioral harassment occur in a day. Take estimates alone 
do not provide information regarding the potential fitness or other 
biological consequences of the reactions on the affected individuals. 
We therefore consider the available activity-specific, environmental, 
and species-specific information to determine the likely nature of the 
modeled behavioral responses and the potential fitness consequences for 
affected individuals.
    Use of sonar and other transducers would typically be transient and 
temporary. The majority of acoustic effects to individual animals from 
sonar and other active sound sources during testing and training 
activities would be primarily from ASW events. It is important to note 
that although ASW is one of the warfare areas of focus during MTEs, 
there are significant periods when active ASW sonars are not in use. 
Nevertheless, behavioral reactions are assumed more likely to be 
significant during MTEs than during other ASW activities due to the 
duration (i.e., multiple days), scale (i.e., multiple sonar platforms), 
and use of high-power hull-mounted sonar in the MTEs. In other words, 
in the range of potential behavioral effects that might expect to be 
part of a response that qualifies as an instance of Level B behavioral 
harassment (which by nature of the way it is modeled/counted, occurs 
within one day), the less severe end might include exposure to 
comparatively lower levels of a sound, at a detectably greater distance 
from the animal, for a few or several minutes, that could result in a 
behavioral response such as avoiding an area that an animal would 
otherwise have chosen to move through or feed in for some amount of 
time or breaking off one or a few feeding bouts. More severe effects 
could occur when the animal gets close enough to the source to receive 
a comparatively higher level, is exposed continuously to one source for 
a longer time, or is exposed intermittently to different sources 
throughout a day. Such effects might result in an animal having a more 
severe flight response and leaving a larger area for a day or more or 
potentially losing feeding opportunities for a day. However, such 
severe behavioral effects are expected to occur infrequently.
    To help assess this, for sonar (LFAS/MFAS/HFAS) used in the HSTT 
Study Area, the Navy provided information estimating the percentage of 
animals that may be taken by Level B harassment under each behavioral 
response function that would occur within 6-dB increments (percentages 
discussed below in the Group and Species-Specific Analyses section). As 
mentioned above, all else being equal, an animal's exposure to a higher 
received level is more likely to result in a behavioral response that 
is more likely to lead to adverse effects, which could more likely 
accumulate to impacts on reproductive success or survivorship of the 
animal, but other contextual factors (such as distance) are important 
also. The majority of Level B harassment takes are expected to be in 
the form of milder responses (i.e., lower-level exposures that still 
rise to the level of take, but would likely be less severe in the range 
of responses that qualify as take) of a generally shorter duration. We 
anticipate more severe effects from takes when animals are exposed to 
higher received levels or at closer proximity to the source. Because 
stocks belonging to the same species and species belonging to taxa that 
share common characteristics are likely to respond and be affected in 
similar ways, these discussions are presented within each species group 
below in the Group and Species-Specific Analyses section. Specifically, 
given a range of behavioral responses that may be classified as Level B 
harassment, to the degree that higher received levels are expected to 
result in more severe behavioral responses, only a smaller percentage 
of the anticipated Level B harassment from Navy activities might 
necessarily be expected to potentially result in more severe responses 
(see the Group and Species-Specific Analyses section below for more 
detailed information). To fully understand the likely impacts of the 
predicted/authorized take on an

[[Page 66980]]

individual (i.e., what is the likelihood or degree of fitness impacts), 
one must look closely at the available contextual information, such as 
the duration of likely exposures and the likely severity of the 
exposures (e.g., whether they will occur for a longer duration over 
sequential days or the comparative sound level that will be received). 
Moore and Barlow (2013) emphasizes the importance of context (e.g., 
behavioral state of the animals, distance from the sound source, etc.) 
in evaluating behavioral responses of marine mammals to acoustic 
sources.
Diel Cycle
    As noted previously, many animals perform vital functions, such as 
feeding, resting, traveling, and socializing on a diel cycle (24-hour 
cycle). Behavioral reactions to noise exposure, when taking place in a 
biologically important context, such as disruption of critical life 
functions, displacement, or avoidance of important habitat, are more 
likely to be significant if they last more than one diel cycle or recur 
on subsequent days (Southall et al., 2007). Henderson et al. (2016) 
found that ongoing smaller scale events had little to no impact on 
foraging dives for Blainville's beaked whale, while multi-day training 
events may decrease foraging behavior for Blainville's beaked whale 
(Manzano-Roth et al., 2016). Consequently, a behavioral response 
lasting less than one day and not recurring on subsequent days is not 
considered severe unless it could directly affect reproduction or 
survival (Southall et al., 2007). Note that there is a difference 
between multiple-day substantive behavioral reactions and multiple-day 
anthropogenic activities. For example, just because an at-sea exercise 
lasts for multiple days does not necessarily mean that individual 
animals are either exposed to those exercises for multiple days or, 
further, exposed in a manner resulting in a sustained multiple day 
substantive behavioral response. Large multi-day Navy exercises such as 
ASW activities, typically include vessels that are continuously moving 
at speeds typically 10-15 kn, or higher, and likely cover large areas 
that are relatively far from shore (typically more than 3 nmi from 
shore) and in waters greater than 600 ft deep. Additionally marine 
mammals are moving as well, which would make it unlikely that the same 
animal could remain in the immediate vicinity of the ship for the 
entire duration of the exercise. Further, the Navy does not necessarily 
operate active sonar the entire time during an exercise. While it is 
certainly possible that these sorts of exercises could overlap with 
individual marine mammals multiple days in a row at levels above those 
anticipated to result in a take, because of the factors mentioned 
above, it is considered unlikely for the majority of takes. However, it 
is also worth noting that the Navy conducts many different types of 
noise-producing activities over the course of the year and it is likely 
that some marine mammals will be exposed to more than one and taken on 
multiple days, even if they are not sequential.
    Durations of Navy activities utilizing tactical sonar sources and 
explosives vary and are fully described in Appendix A (Navy Activity 
Descriptions) of the HSTT FEIS/OEIS. Sonar used during ASW would impart 
the greatest amount of acoustic energy of any category of sonar and 
other transducers analyzed in the Navy's rulemaking/LOA application and 
include hull-mounted, towed, sonobuoy, helicopter dipping, and torpedo 
sonars. Most ASW sonars are MFAS (1-10 kHz); however, some sources may 
use higher or lower frequencies. ASW training activities using hull 
mounted sonar proposed for the HSTT Study Area generally last for only 
a few hours. Some ASW training and testing can generally last for 2-10 
days, or as much as 21 days for an MTE-Large Integrated ASW (see Table 
4). For these multi-day exercises there will typically be extended 
intervals of non-activity in between active sonar periods. Because of 
the need to train in a large variety of situations, the Navy does not 
typically conduct successive ASW exercises in the same locations. Given 
the average length of ASW exercises (times of sonar use) and typical 
vessel speed, combined with the fact that the majority of the cetaceans 
would not likely remain in proximity to the sound source, it is 
unlikely that an animal would be exposed to LFAS/MFAS/HFAS at levels or 
durations likely to result in a substantive response that would then be 
carried on for more than one day or on successive days.
    Most planned explosive events are scheduled to occur over a short 
duration (1-8 hours); however, the explosive component of the activity 
only lasts for minutes (see Tables 4 through 7). Although explosive 
exercises may sometimes be conducted in the same general areas 
repeatedly, because of their short duration and the fact that they are 
in the open ocean and animals can easily move away, it is similarly 
unlikely that animals would be exposed for long, continuous amounts of 
time, or demonstrate sustained behavioral responses. Although SINKEXs 
may last for up to 48 hrs (4-8 hrs, possibly 1-2 days), they are almost 
always completed in a single day and only one event is planned annually 
for the HSTT training activities. They are stationary and conducted in 
deep, open water where fewer marine mammals would typically be expected 
to be encountered. They also have shutdown procedures and rigorous 
monitoring, i.e., during the activity, the Navy conducts passive 
acoustic monitoring and visually observes for marine mammals 90 min 
prior to the first firing, during the event, and 2 hrs after sinking 
the vessel. All of these factors make it unlikely that individuals 
would be exposed to the exercise for extended periods or on consecutive 
days.
Assessing the Number of Individuals Taken and the Likelihood of 
Repeated Takes
    As described previously, Navy modeling uses the best available 
science to predict the instances of exposure above certain acoustic 
thresholds, which are equated, as appropriate, to harassment takes (and 
further corrected to account for mitigation and avoidance). As further 
noted, for active acoustics it is more challenging to parse out the 
number of individuals taken by Level B harassment and the number of 
times those individuals are taken from this larger number of instances. 
One method that NMFS can use to help better understand the overall 
scope of the impacts is to compare these total instances of take 
against the abundance of that stock. For example, if there are 100 
harassment takes in a population of 100, one can assume either that 
every individual was exposed above acoustic thresholds in no more than 
one day, or that some smaller number were exposed in one day but a few 
of those individuals were exposed multiple days within a year. Where 
the instances of take exceed 100 percent of the population, multiple 
takes of some individuals are predicted and expected to occur within a 
year. Generally speaking, the higher the number of takes as compared to 
the population abundance, the more multiple takes of individuals are 
likely, and the higher the actual percentage of individuals in the 
population that are likely taken at least once in a year. We look at 
this comparative metric to give us a relative sense of where larger 
portions of the stocks are being taken by Navy activities and where 
there is a higher likelihood that the same individuals are being taken 
across multiple days and where that number of days might be higher. It 
also provides a relative picture of the scale of impacts to each stock.

[[Page 66981]]

    In the ocean, unlike a modeling simulation with static animals, the 
use of sonar and other active acoustic sources is often transient, and 
is unlikely to repeatedly expose the same individual animals within a 
short period, for example within one specific exercise. However, some 
repeated exposures across different activities would likely occur over 
the year, especially where numerous activities occur in generally the 
same area (for example on instrumented ranges) with more resident 
species. In short, we expect that the total anticipated takes represent 
exposures of a smaller number of individuals of which some would be 
exposed multiple times, but based on the nature of the Navy's 
activities and the movement patterns of marine mammals, it is unlikely 
that any particular subset would be taken over more than several 
sequential days (with a few possible exceptions discussed in the stock-
specific conclusions).
    When calculating the proportion of a population affected by takes 
(e.g., the number of takes divided by population abundance), which can 
also be helpful in estimating the number of days over which some 
individuals may be taken, it is important to choose an appropriate 
population estimate against which to make the comparison. The SARs 
provide the official population estimate for a given species or stock 
in U.S. waters in a given year (and are typically based solely on the 
most recent survey data). When the stock is known to range well outside 
of U.S. EEZ boundaries, population estimates based on surveys conducted 
only within the U.S. EEZ are known to be underestimates. In the case of 
both Hawaii and Southern California (near which mutually exclusive sets 
of stocks are impacted by Navy activities), the areas of Navy 
activities across which take is estimated have boundaries that vary 
significantly from the U.S. EEZ boundaries, and further vary 
differently in Hawaii versus Southern California. For example, the 
Study Area encompasses large areas of ocean space outside U.S. waters 
(i.e., extending seaward beyond the U.S. EEZ) or, separately, many 
stocks range up and down the U.S., Canada, and/or Mexican West Coast, 
while Navy activities covered in this rule are confined north-south to 
the Southern California area included in the Navy study area. 
Additionally, the information used to estimate take includes the data 
underlying the SAR abundances, as well as other survey data, used 
together to model density layers. If takes are calculated from another 
dataset (for example a broader sample of survey data) and compared to 
the population estimate from the SARs, it may distort the percent of 
the population affected or an assessment of how many days a year 
individuals may be taken because of different population baselines. 
However, when the SAR considers the larger area within which the stock 
ranges it may contribute to a more appropriate sense of the proportion 
of the population taken. Accordingly, in calculating the percentage of 
takes versus abundance for each stock in order to assist in 
understanding both the percentage of the stock affected, as well as how 
many days across a year individuals could be taken, we use the data 
most appropriate for the situation.
    For Hawaii, a fair number of stocks range outside of the U.S. EEZ, 
the majority of the take occurs inside the U.S. EEZ, and a fair number 
of stocks do not have abundance estimates in the SAR. Therefore, for 
the purposes of this analytical exercise, the tables included in the 
group-specific analyses below include percentages calculated for the 
Navy's take in the U.S. EEZ versus the Navy-estimated abundances within 
the U.S. EEZ, as well as the take in the whole Study Area versus the 
Navy-estimated abundances in the whole area. However, where appropriate 
for a given stock (and the explanation will be provided in the 
narrative), the SAR abundance may also be used for comparison. For 
Southern California, while a fair number of stocks range seaward from 
the U.S. EEZ, many also range significantly north and south outside the 
Navy Study Area and that abundance is captured by the SAR. 
Additionally, generally speaking, except where stocks are more coastal, 
a higher percentage of the take occurs outside of the U.S. EEZ than 
around Hawaii (though the majority are still inside the U.S. EEZ). 
Accordingly, rather than focus on the take in the U.S. EEZ, the tables 
included in the group-specific analyses below include percentages 
calculated for the Navy's take in the entire Study Area as compared 
against both the Navy-calculated abundance in the entire Study Area and 
the SARs.
    The estimates found in NMFS' SARs remain the official estimates of 
stock abundance where they are current. These estimates are typically 
generated from the most recent shipboard and/or aerial surveys 
conducted. Studies based on abundance and distribution surveys 
restricted to U.S. waters are unable to detect temporal shifts in 
distribution beyond U.S. waters that might account for any changes in 
abundance within U.S. waters. In some cases, NMFS' abundance estimates 
show substantial year-to-year variability. However, for highly 
migratory species (e.g., large whales) or those whose geographic 
distribution extends well beyond the boundaries of the Navy's study 
area (e.g., populations with distribution along the entire California 
Current versus just SOCAL), comparisons to the SAR may be more 
appropriate. This is because the Navy's acoustic modeling process does 
not horizontally move animats, and therefore does not account for 
immigration and emigration within the study area. For instance, while 
it may be accurate that the abundance of animals in Southern California 
at any one time for a particular species is 200 individuals, if the 
species is highly migratory or has large daily home ranges, it is not 
likely that the same 200 individuals would be present every day. A good 
descriptive example is blue whales, which tagging data have shown 
traverse the SOCAL area in a few days to weeks on their migrations. 
Therefore, at any one time there may be a stable number of animals, but 
over the course of the entire year the entire population may cycle 
through SOCAL. Therefore, when comparing the estimated takes to an 
abundance, in this case the SAR, which represents the total population, 
may be more appropriate than the Navy's modeled abundance for SOCAL. In 
each of the species write-ups for the negligible impact assessment we 
explain which abundance was used for making the comparison of takes to 
the impacts to the population.
    NMFS' Southwest Fisheries Science Center derived densities for the 
Navy, and NMFS supports the use of spatially and temporally explicit 
density models that vary in space and time to estimate their potential 
impacts to species. See the U.S. Navy Marine Species Density Database 
Phase III Hawaii-Southern California Training and Testing Area 
Technical Report to learn more on how the Navy selects density 
information and the models selected for individual species. These 
models may better characterize how Navy impacts can vary in space and 
time but often predict different population abundances than the SARs.
    Models may predict different population abundances for many 
reasons. The models may be based on different data sets or different 
temporal predictions may be made. The SARs are often based on single 
years of NMFS surveys, whereas the models used by the Navy generally 
include multiple years of survey data from NMFS, the Navy, and other 
sources. To present a single, best estimate, the SARs often use a 
single season survey where they have the best spatial coverage 
(generally Summer). Navy models often use

[[Page 66982]]

predictions for multiple seasons, where appropriate for the species, 
even when survey coverage in non-Summer seasons is limited, to 
characterize impacts over multiple seasons as Navy activities may occur 
in any season. Predictions may be made for different spatial extents. 
Many different, but equally valid, habitat and density modeling 
techniques exist and these can also be the cause of differences in 
population predictions. Differences in population estimates may be 
caused by a combination of these factors. Even similar estimates should 
be interpreted with caution and differences in models should be fully 
understood before drawing conclusions.
Temporary Threshold Shift
    NMFS and the Navy have estimated that some individuals of some 
species of marine mammals may sustain some level of TTS from active 
sonar. As mentioned previously, in general, TTS can last from a few 
minutes to days, be of varying degree, and occur across various 
frequency bandwidths, all of which determine the severity of the 
impacts on the affected individual, which can range from minor to more 
severe. Tables 72-77 indicate the number of takes by TTS that may be 
incurred by different stocks from exposure to active sonar and 
explosives. The modeling predicts that no TTS will result from air guns 
or pile driving activities. The TTS sustained by an animal is primarily 
classified by three characteristics:
    1. Frequency--Available data (of mid-frequency hearing specialists 
exposed to mid- or high-frequency sounds; Southall et al., 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 MF sources, which are the highest power and most 
numerous sources and the ones that cause the most take, utilize the 1-
10 kHz frequency band, which suggests that if TTS were to be induced by 
any of these MF sources it would be in a frequency band somewhere 
between approximately 2 and 20 kHz, which is in the range of 
communication calls for many odontocetes, but below the range of the 
echolocation signals used for foraging. There are fewer hours of HF 
source use and the sounds would attenuate more quickly, plus they have 
lower source levels, but if an animal were to incur TTS from these 
sources, it would cover a higher frequency range (sources are between 
10 and 100 kHz, which means that TTS could range up to 200 kHz), which 
could overlap with the range in which some odontocetes communicate or 
echolocate. However, HF systems are typically used less frequently and 
for shorter time periods than surface ship and aircraft MF systems, so 
TTS from these sources is unlikely. There are fewer LF sources and the 
majority are used in the more readily mitigated testing environment, 
and TTS from LF sources would most likely occur below 2 kHz, which is 
in the range where many mysticetes communicate and also where other 
non-communication auditory cues are located (waves, snapping shrimp, 
fish prey). TTS from explosives would be broadband. Also of note, the 
majority of sonar sources from which TTS may be incurred occupy a 
narrow frequency band, which means that the TTS incurred would also be 
across a narrower band (i.e., not affecting the majority of an animal's 
hearing range). This frequency provides information about the cues to 
which a marine mammal may be temporarily less sensitive, but not the 
degree or duration of sensitivity loss.
    2. Degree of the shift (i.e., by how many dB the sensitivity of the 
hearing is reduced)--Generally, both the degree of TTS and the duration 
of TTS will be greater if the marine mammal is exposed to a higher 
level of energy (which would occur when the peak dB level is higher or 
the duration is longer). The threshold for the onset of TTS was 
discussed previously in this rule. An animal would have to approach 
closer to the source or remain in the vicinity of the sound source 
appreciably longer to increase the received SEL, which would be 
difficult considering the Lookouts and the nominal speed of an active 
sonar vessel (10-15 kn) and the relative motion between the sonar 
vessel and the animal. In the TTS studies discussed in the proposed 
rule, some using exposures of almost an hour in duration or up to 217 
SEL, most of the TTS induced was 15 dB or less, though Finneran et al. 
(2007) induced 43 dB of TTS with a 64-second exposure to a 20 kHz 
source. However, since any hull-mounted sonar such as the SQS-53 
(MFAS), emits a ping typically every 50 seconds, incurring those levels 
of TTS is highly unlikely. In short, given the anticipated duration and 
levels of sound exposure, we would not expect marine mammals to incur 
more than relatively low levels of TTS (i.e., single digits of 
sensitivity loss). To add context to this degree of TTS, individual 
marine mammals may regularly experience variations of 6dB differences 
in hearing sensitivity across time (Finneran et al., 2000, 2002; 
Schlundt et al., 2000).
    3. Duration of TTS (recovery time)--In the TTS laboratory studies 
(as discussed in the proposed rule), some using exposures of almost an 
hour in duration or up to 217 SEL, almost all individuals recovered 
within 1 day (or less, often in minutes), although in one study 
(Finneran et al., 2007), recovery took 4 days.
    Based on the range of degree and duration of TTS reportedly induced 
by exposures to non-pulse sounds of energy higher than that to which 
free-swimming marine mammals in the field are likely to be exposed 
during LFAS/MFAS/HFAS training and testing exercises in the HSTT Study 
Area, it is unlikely that marine mammals would ever sustain a TTS from 
MFAS that alters their sensitivity by more than 20 dB for more than a 
few hours--and any incident of TTS would likely be far less severe due 
to the short duration of the majority of the events and the speed of a 
typical vessel, especially given the fact that the higher power sources 
resulting in TTS are predominantly intermittent, which have been shown 
to result in shorter durations of TTS. Also, for the same reasons 
discussed in the Analysis and Negligible Impact Determination--Diel 
Cycle section, and because of the short distance within which animals 
would need to approach the sound source, it is unlikely that animals 
would be exposed to the levels necessary to induce TTS in subsequent 
time periods such that their recovery is impeded. Additionally, though 
the frequency range of TTS that marine mammals might sustain would 
overlap with some of the frequency ranges of their vocalization types, 
the frequency range of TTS from MFAS (the source from which TTS would 
most likely be sustained because the higher source level and slower 
attenuation make it more likely that an animal would be exposed to a 
higher received level) would not usually span the entire frequency 
range of one vocalization type, much less span all types of 
vocalizations or other critical auditory cues.
    Tables 72-77 indicate the number of incidental takes by TTS that 
are likely to result from the Navy's activities. As a general point, 
the majority of these TTS takes are the result of exposure to hull-
mounted MFAS (MF narrower band sources), with fewer from explosives 
(broad-band lower frequency sources), and even fewer from LF or HF 
sonar sources (narrower band). As described above, we expect the 
majority of these takes to be in the form of mild (single-digit), 
short-term (minutes to hours), narrower band (only affecting a portion 
of the animal's hearing range) TTS. This means that for one to several 
times per year, for several minutes to maybe a few hours (high end) 
each, a

[[Page 66983]]

taken individual will have slightly diminished hearing sensitivity 
(slightly more than natural variation, but nowhere near total deafness) 
more often within a narrower mid- to higher frequency band that may 
overlap part (but not all) of a communication, echolocation, or 
predator range, but sometimes across a lower or broader bandwidth. The 
significance of TTS is also related to the auditory cues that are 
germane within the time period that the animal incurs the TTS--for 
example, if an odontocete has TTS at echolocation frequencies, but 
incurs it at night when it is resting and not feeding, for example, it 
is not impactful. In short, the expected results of any one of these 
small number of mild TTS occurrences could be that (1) it does not 
overlap signals that are pertinent to that animal in the given time 
period, (2) it overlaps parts of signals that are important to the 
animal, but not in a manner that impairs interpretation, or (3) it 
reduces detectability of an important signal to a small degree for a 
short amount of time--in which case the animal may be aware and be able 
to compensate (but there may be slight energetic cost), or the animal 
may have some reduced opportunities (e.g., to detect prey) or reduced 
capabilities to react with maximum effectiveness (e.g., to detect a 
predator or navigate optimally). However, given the small number of 
times that any individual might incur TTS, the low degree of TTS and 
the short anticipated duration, and the low likelihood that one of 
these instances would occur in a time period in which the specific TTS 
overlapped the entirety of a critical signal, it is unlikely that TTS 
of the nature expected to result from Navy activities would result in 
behavioral changes or other impacts that would impact any individual's 
(of any hearing sensitivity) reproduction or survival.
Acoustic Masking or Communication Impairment
    The ultimate potential impacts of masking on an individual (if it 
were to occur) are similar to those discussed for TTS, but an important 
difference is that masking only occurs during the time of the signal 
(and potential secondary arrivals of indirect rays) versus TTS, which 
continues beyond the duration of the signal. Fundamentally, masking is 
referred to as a chronic effect because one of the key harmful 
components of masking is its duration--the fact that an animal would 
have reduced ability to hear or interpret critical cues becomes much 
more likely to cause a problem the longer it is occurring. Also 
inherent in the concept of masking is the fact that the potential for 
the effect is only present during the times that the animal and the 
source are in close enough proximity for the effect to occur (and 
further, this time period would need to coincide with a time that the 
animal was utilizing sounds at the masked frequency). As our analysis 
has indicated, because of the relative movement of vessels and the 
species involved in this rule, we do not expect the exposures with the 
potential for masking to be of a long duration. In addition, masking is 
fundamentally more of a concern at lower frequencies, because low 
frequency signals propagate significantly further than higher 
frequencies and because they are more likely to overlap both the 
narrower LF calls of mysticetes, as well as many non-communication cues 
such as fish and invertebrate prey, and geologic sounds that inform 
navigation. Masking is also more of a concern from continuous sources 
(versus intermittent sonar signals) where there is no quiet time 
between pulses within which auditory signals can be detected and 
interpreted. For these reasons, dense aggregations of, and long 
exposure to, continuous LF activity, such as shipping or seismic airgun 
operation (the latter signal changes from intermittent to continuous at 
distance), are much more of a concern for masking, whereas 
comparatively short-term exposure to the predominantly intermittent 
pulses of often narrow frequency range MFAS or HFAS, or explosions are 
not expected to result in a meaningful amount of masking. While the 
Navy occasionally uses LF and more continuous sources, it is not in the 
contemporaneous aggregate amounts that would accrue to a masking 
concern. Specifically, the nature of the activities and sound sources 
used by the Navy do not support the likelihood of a level of masking 
accruing that would have the potential to affect reproductive success 
or survival. Additional detail is provided below.
    Standard hull-mounted MFAS typically ping every 50 seconds for 
hull-mounted sources. Some hull-mounted anti-submarine sonars can also 
be used in an object detection mode known as ``Kingfisher'' mode (e.g., 
used on vessels when transiting to and from port) where pulse length is 
shorter but pings are much closer together in both time and space since 
the vessel goes slower when operating in this mode. For the majority of 
sources, the pulse length is significantly shorter than hull-mounted 
active sonar, on the order of several microseconds to tens of 
milliseconds. Some of the vocalizations that many marine mammals make 
are less than one second long, so, for example with hull-mounted sonar, 
there would be a 1 in 50 chance (only if the source was in close enough 
proximity for the sound to exceed the signal that is being detected) 
that a single vocalization might be masked by a ping. However, when 
vocalizations (or series of vocalizations) are longer than one second, 
masking would not occur. Additionally, when the pulses are only several 
microseconds long, the majority of most animals' vocalizations would 
not be masked.
    Most ASW sonars and countermeasures use MF frequencies and a few 
use LF and HF frequencies. Most of these sonar signals are limited in 
the temporal, frequency, and spatial domains. The duration of most 
individual sounds is short, lasting up to a few seconds each. A few 
systems operate with higher duty cycles or nearly continuously, but 
they typically use lower power, which means that an animal would have 
to be closer, or in the vicinity for a longer time, to be masked to the 
same degree as by a higher level source. Nevertheless, masking could 
occasionally occur at closer ranges to these high-duty cycle and 
continuous active sonar systems, but as described previously, it would 
be expected to be of a short duration when the source and animal are in 
close proximity. Most ASW activities are geographically dispersed and 
last for only a few hours, often with intermittent sonar use even 
within this period. Most ASW sonars also have a narrow frequency band 
(typically less than one-third octave). These factors reduce the 
likelihood of sources causing significant masking. HF signals (above 10 
kHz) attenuate more rapidly in the water due to absorption than do 
lower frequency signals, thus producing only a very small zone of 
potential masking. If masking or communication impairment were to occur 
briefly, it would more likely be in the frequency range of MFAS (the 
more powerful source), which overlaps with some odontocete 
vocalizations (but few mysticete vocalizations); however, it would 
likely not mask the entirety of any particular vocalization, 
communication series, or other critical auditory cue, because the 
signal length, frequency, and duty cycle of the MFAS/HFAS signal does 
not perfectly resemble the characteristics of any single marine mammal 
species' vocalizations.
    Masking could occur briefly in mysticetes due to the overlap 
between their low-frequency vocalizations and the dominant frequencies 
of airgun pulses. However, masking in odontocetes or pinnipeds is less 
likely

[[Page 66984]]

unless the airgun activity is in close range when the pulses are more 
broadband. Masking is more likely to occur in the presence of 
broadband, relatively continuous noise sources such as during vibratory 
pile driving and from vessels, however, the duration of temporal and 
spatial overlap with any individual animal and the spatially separated 
sources that the Navy uses would not be expected to result in more than 
short-term, low impact masking that would not affect reproduction or 
survival.
    The other sources used in Navy training and testing, many of either 
higher frequencies (meaning that the sounds generated attenuate even 
closer to the source) or lower amounts of operation, are similarly not 
expected to result in masking. For the reasons described here, any 
limited masking that could potentially occur would be minor and short-
term and not expected to have adverse impacts on reproductive success 
or survivorship.
PTS From Sonar Acoustic Sources and Explosives and Tissue Damage From 
Explosives
    Tables 72-77 indicate the number of individuals of each of species 
and stock for which Level A harassment in the form of PTS resulting 
from exposure to active sonar and/or explosives is estimated to occur. 
Tables 72-77 also indicate the number of individuals of each species 
and stock for which Level A harassment in the form of tissue damage 
resulting from exposure to explosive detonations is estimated to occur. 
The number of individuals to potentially incur PTS annually (from sonar 
and explosives) for the predicted species ranges from 0 to 209 (209 is 
for Dall's porpoise), but is more typically 0-10 (with the exception of 
several other species that range up to 97). Only five stocks (three 
dolphins and two pinnipeds) have the potential to incur tissue damage 
from explosives and the number of individuals from any given stock 
ranges from one to ten.
    NMFS believes that many marine mammals would deliberately avoid 
exposing themselves to the received levels of active sonar necessary to 
induce injury by moving away from or at least modifying their path to 
avoid a close approach. Additionally, in the unlikely event that an 
animal approaches the sonar-emitting vessel at a close distance, NMFS 
believes that the mitigation measures (i.e., shutdown/powerdown zones 
for active sonar) would typically ensure that animals would not be 
exposed to injurious levels of sound. As discussed previously, the Navy 
utilizes both aerial (when available) and passive acoustic monitoring 
(during ASW exercises, passive acoustic detections are used as a cue 
for Lookouts' visual observations when passive acoustic assets are 
already participating in an activity) in addition to Lookouts on 
vessels to detect marine mammals for mitigation implementation. As 
discussed previously, the Navy utilized a post-modeling quantitative 
assessment to adjust the take estimates based on avoidance and the 
likely success of some portion of the mitigation measures. As is 
typical in predicting biological responses, it is challenging to 
predict exactly how avoidance and mitigation will affect the take of 
marine mammals, and therefore the Navy erred on the side of caution in 
choosing a method that would more likely still overestimate the take by 
PTS to some degree. Nonetheless, these modified Level A harassment take 
numbers represent the maximum number of instances in which marine 
mammals would be reasonably expected to incur either PTS or tissue 
damage, and we have analyzed them accordingly.
    If a marine mammal is able to approach a surface vessel within the 
distance necessary to incur PTS in spite of the mitigation measures, 
the likely speed of the vessel (nominally 10-15 kn) and relative motion 
of the vessel would make it very difficult for the animal to remain in 
range long enough to accumulate enough energy to result in more than a 
mild case of PTS. As mentioned previously in relation to TTS, the 
likely consequences to the health of an individual that incurs PTS can 
range from mild to more serious dependent upon the degree of PTS and 
the frequency band it is in. The majority of any PTS incurred as a 
result of exposure to Navy sources would be expected to be in the 2-20 
kHz region (resulting from the most powerful hull-mounted sonar) and 
could overlap a small portion of the communication frequency range of 
many odontocetes, whereas other marine mammal groups have communication 
calls at lower frequencies. Regardless of the frequency band though, 
the more important point in this case is that any PTS accrued as a 
result of exposure to Navy activities would be expected to be of a 
small amount (single digits). Permanent loss of some degree of hearing 
is a normal occurrence for older animals, and many animals are able to 
compensate for the shift, both in old age or at younger ages as the 
result of stressor exposure. While a small loss of hearing sensitivity 
may include some degree of energetic costs for compensating or may mean 
some small loss of opportunities or detection capabilities, at the 
expected scale it would be unlikely to impact behaviors, opportunities, 
or detection capabilities to a degree that would interfere with 
reproductive success or survival.
    We also assume that the acoustic exposures sufficient to trigger 
onset PTS (or TTS) would be accompanied by physiological stress 
responses, although the sound characteristics that correlate with 
specific stress responses in marine mammals are poorly understood. As 
discussed above for Level B behavioral harassment, we would not expect 
the Navy's generally short-term, intermittent, and (in the case of 
sonar) transitory activities to create conditions of long-term, 
continuous noise leading to long-term physiological stress responses in 
marine mammals that could affect reproduction or survival.
    The Navy implements mitigation measures (described in the 
Mitigation Measures section) during explosive activities, including 
delaying detonations when a marine mammal is observed in the mitigation 
zone. Nearly all explosive events will occur during daylight hours to 
improve the sightability of marine mammals and thereby improve 
mitigation effectiveness. Observing for marine mammals during the 
explosive activities will include aerial and passive acoustic detection 
methods (when they are available and part of the activity) before the 
activity begins, in order to cover the mitigation zones that can range 
from 200 yds (183 m) to 2,500 yds (2,286 m) depending on the source 
(e.g., explosive sonobuoy, explosive torpedo, explosive bombs), and 2.5 
nmi for sinking exercise (see Tables 48-57).
    We analyze the type and amount of take by Level A harassment in 
Tables 39 through 41. Generally speaking, tissue damage injuries from 
explosives could range from minor lung injuries (the most sensitive 
organ and first to be affected) that consist of some short-term 
reduction of health and fitness immediately following the injury that 
heals quickly and will not have any discernible long-term effects, up 
to more impactful permanent injuries across multiple organs that may 
cause health problems and negatively impact reproductive success (i.e., 
increase the time between pregnancies or even render reproduction 
unlikely) but fall just short of a ``serious injury'' by virtue of the 
fact that the animal is not expected to die. Nonetheless, due to the 
Navy's mitigation and detection capabilities, we would not expect 
marine mammals to typically be exposed to a more severe blast located 
closer to the source--so the impacts

[[Page 66985]]

likely would be on the less severe end. It is still difficult to 
evaluate how these injuries may or may not impact an animal's fitness, 
however, these effects are only seen in very small numbers (single 
digits with the exception of two stocks) and in species of fairly high 
to very high abundances. In short, it is unlikely that any, much less 
all, of the small number of injuries accrued to any one stock would 
result in reduced reproductive success of any individuals, but even if 
a few did, the status of the affected stocks are such that it would not 
be expected to adversely impact rates of reproduction (and PTS of the 
low severity anticipated here is not expected to affect the survival of 
any individual marine mammals).
Serious Injury and Mortality
    NMFS is authorizing a very small number of serious injuries or 
mortalities that could occur in the event of a ship strike or as a 
result of marine mammal exposure to explosive detonations. We note here 
that the takes from potential ship strikes or explosive exposures 
enumerated below could result in non-serious injury, but their worst 
potential outcome (mortality) is analyzed for the purposes of the 
negligible impact determination.
    In addition, we discuss here the connection, and differences, 
between the legal mechanisms for authorizing incidental take under 
section 101(a)(5) for activities such as the Navy's testing and 
training in the HSTT Study Area, and for authorizing incidental take 
from commercial fisheries. In 1988, Congress amended the MMPA's 
provisions for addressing incidental take of marine mammals in 
commercial fishing operations. Congress directed NMFS to develop and 
recommend a new long-term regime to govern such incidental taking (see 
MMC, 1994). The need to develop a system suited to the unique 
circumstances of commercial fishing operations led NMFS to suggest a 
new conceptual means and associated regulatory framework. That concept, 
PBR, and a system for developing plans containing regulatory and 
voluntary measures to reduce incidental take for fisheries that exceed 
PBR were incorporated as sections 117 and 118 in the 1994 amendments to 
the MMPA. In Conservation Council for Hawaii v. National Marine 
Fisheries Service, 97 F. Supp.3d 1210 (D. Haw. 2015), which concerned a 
challenge to NMFS' regulations and LOAs to the Navy for activities 
assessed in the 2013-2018 HSTT MMPA rulemaking, the Court ruled that 
NMFS' failure to consider PBR when evaluating lethal takes in the 
negligible impact analysis under section 101(a)(5)(A) violated the 
requirement to use the best available science.
    PBR is defined in section 3 of the MMPA as ``the maximum number of 
animals, not including natural mortalities, that may be removed from a 
marine mammal stock while allowing that stock to reach or maintain its 
optimum sustainable population'' (OSP) and, although not controlling, 
can be one measure considered among other factors when evaluating the 
effects of M/SI on a marine mammal species or stock during the section 
101(a)(5)(A) process. OSP is defined in section 3 of the MMPA as ``the 
number of animals which will result in the maximum productivity of the 
population or the species, keeping in mind the carrying capacity of the 
habitat and the health of the ecosystem of which they form a 
constituent element.'' Through section 2, an overarching goal of the 
statute is to ensure that each species or stock of marine mammal is 
maintained at or returned to its OSP.
    PBR values are calculated by NMFS as the level of annual removal 
from a stock that will allow that stock to equilibrate within OSP at 
least 95 percent of the time, and is the product of factors relating to 
the minimum population estimate of the stock (N<INF>min</INF>), the 
productivity rate of the stock at a small population size, and a 
recovery factor. Determination of appropriate values for these three 
elements incorporates significant precaution, such that application of 
the parameter to the management of marine mammal stocks may be 
reasonably certain to achieve the goals of the MMPA. For example, 
calculation of the minimum population estimate (N<INF>min</INF>) 
incorporates the level of precision and degree of variability 
associated with abundance information, while also providing reasonable 
assurance that the stock size is equal to or greater than the estimate 
(Barlow et al., 1995), typically by using the 20th percentile of a log-
normal distribution of the population estimate. In general, the three 
factors are developed on a stock-specific basis in consideration of one 
another in order to produce conservative PBR values that appropriately 
account for both imprecision that may be estimated, as well as 
potential bias stemming from lack of knowledge (Wade, 1998).
    Congress called for PBR to be applied within the management 
framework for commercial fishing incidental take under section 118 of 
the MMPA. As a result, PBR cannot be applied appropriately outside of 
the section 118 regulatory framework without consideration of how it 
applies within the section 118 framework, as well as how the other 
statutory management frameworks in the MMPA differ from the framework 
in section 118. PBR was not designed and is not used as an absolute 
threshold limiting commercial fisheries. Rather, it serves as a means 
to evaluate the relative impacts of those activities on marine mammal 
stocks. Even where commercial fishing is causing M/SI at levels that 
exceed PBR, the fishery is not suspended. When M/SI exceeds PBR in the 
commercial fishing context under section 118, NMFS may develop a take 
reduction plan, usually with the assistance of a take reduction team. 
The take reduction plan will include measures to reduce and/or minimize 
the taking of marine mammals by commercial fisheries to a level below 
the stock's PBR. That is, where the total annual human-caused M/SI 
exceeds PBR, NMFS is not required to halt fishing activities 
contributing to total M/SI but rather utilizes the take reduction 
process to further mitigate the effects of fishery activities via 
additional bycatch reduction measures. In other words, under section 
118 of the MMPA, PBR does not serve as a strict cap on the operation of 
commercial fisheries that may incidentally take marine mammals.
    Similarly, to the extent PBR may be relevant when considering the 
impacts of incidental take from activities other than commercial 
fisheries, using it as the sole reason to deny (or issue) incidental 
take authorization for those activities would be inconsistent with 
Congress's intent under section 101(a)(5), NMFS' long-standing 
regulatory definition of ``negligible impact,'' and the use of PBR 
under section 118. The standard for authorizing incidental take for 
activities other than commercial fisheries under section 101(a)(5) 
continues to be, among other things that are not related to PBR, 
whether the total taking will have a negligible impact on the species 
or stock. Nowhere does section 101(a)(5)(A) reference use of PBR to 
make the negligible impact finding or authorize incidental take through 
multi-year regulations, nor does its companion provision at 
101(a)(5)(D) for authorizing non-lethal incidental take under the same 
negligible-impact standard. NMFS' MMPA implementing regulations state 
that take has a negligible impact when it does not ``adversely affect 
the species or stock through effects on annual rates of recruitment or 
survival''--likewise without reference to PBR. When Congress amended 
the MMPA in 1994 to add section 118 for commercial fishing, it did not 
alter the standards for authorizing non-commercial fishing

[[Page 66986]]

incidental take under section 101(a)(5), implicitly acknowledging that 
the negligible impact standard under section 101(a)(5) is separate from 
the PBR metric under section 118. In fact, in 1994 Congress also 
amended section 101(a)(5)(E) (a separate provision governing commercial 
fishing incidental take for species listed under the ESA) to add 
compliance with the new section 118 but retained the standard of the 
negligible impact finding under section 101(a)(5)(A) (and section 
101(a)(5)(D)), showing that Congress understood that the determination 
of negligible impact and application of PBR may share certain features 
but are, in fact, different.
    Since the introduction of PBR in 1994, NMFS had used the concept 
almost entirely within the context of implementing sections 117 and 118 
and other commercial fisheries management-related provisions of the 
MMPA. Prior to the Court's ruling in Conservation Council for Hawaii v. 
National Marine Fisheries Service and consideration of PBR in a series 
of section 101(a)(5) rulemakings, there were a few examples where PBR 
had informed agency deliberations under other MMPA sections and 
programs, such as playing a role in the issuance of a few scientific 
research permits and subsistence takings. But as the Court found when 
reviewing examples of past PBR consideration in Georgia Aquarium v. 
Pritzker, 135 F. Supp. 3d 1280 (N.D. Ga. 2015), where NMFS had 
considered PBR outside the commercial fisheries context, ``it has 
treated PBR as only one `quantitative tool' and [has not used it] as 
the sole basis for its impact analyses.'' Further, the agency's 
thoughts regarding the appropriate role of PBR in relation to MMPA 
programs outside the commercial fishing context have evolved since the 
agency's early application of PBR to section 101(a)(5) decisions. 
Specifically, NMFS' denial of a request for incidental take 
authorization for the U.S. Coast Guard in 1996 seemingly was based on 
the potential for lethal take in relation to PBR and did not appear to 
consider other factors that might also have informed the potential for 
ship strike in relation to negligible impact (61 FR 54157; October 17, 
1996).
    The MMPA requires that PBR be estimated in SARs and that it be used 
in applications related to the management of take incidental to 
commercial fisheries (i.e., the take reduction planning process 
described in section 118 of the MMPA and the determination of whether a 
stock is ``strategic'' as defined in section 3), but nothing in the 
statute requires the application of PBR outside the management of 
commercial fisheries interactions with marine mammals. Nonetheless, 
NMFS recognizes that as a quantitative metric, PBR may be useful as a 
consideration when evaluating the impacts of other human-caused 
activities on marine mammal stocks. Outside the commercial fishing 
context, and in consideration of all known human-caused mortality, PBR 
can help inform the potential effects of M/SI requested to be 
authorized under 101(a)(5)(A). As noted by NMFS and the U.S. Fish and 
Wildlife Service in our implementation regulations for the 1986 
amendments to the MMPA (54 FR 40341, September 29, 1989), the Services 
consider many factors, when available, in making a negligible impact 
determination, including, but not limited to, the status of the species 
or stock relative to OSP (if known); whether the recruitment rate for 
the species or stock is increasing, decreasing, stable, or unknown; the 
size and distribution of the population; and existing impacts and 
environmental conditions. In this multi-factor analysis, PBR can be a 
useful indicator for when, and to what extent, the agency should take 
an especially close look at the circumstances associated with the 
potential mortality, along with any other factors that could influence 
annual rates of recruitment or survival.
    When considering PBR during evaluation of effects of M/SI under 
section 101(a)(5)(A), we first calculate a metric for each species or 
stock that incorporates information regarding ongoing anthropogenic M/
SI from all sources into the PBR value (i.e., PBR minus the total 
annual anthropogenic mortality/serious injury estimate in the SAR), 
which is called ``residual PBR.'' (Wood et al., 2012). We first focus 
our analysis on residual PBR because it incorporates anthropogenic 
mortality occurring from other sources. If the ongoing human-caused 
mortality from other sources does not exceed PBR, then residual PBR is 
a positive number, and we consider how the anticipated or potential 
incidental M/SI from the activities being evaluated compares to 
residual PBR using the framework in the following paragraph. If the 
ongoing anthropogenic mortality from other sources already exceeds PBR, 
then residual PBR is a negative number and we consider the M/SI from 
the activities being evaluated as described further below.
    When ongoing total anthropogenic mortality from the applicant's 
specified activities does not exceed PBR and residual PBR is a positive 
number, as a simplifying analytical tool we first consider whether the 
specified activities could cause incidental M/SI that is less than 10 
percent of residual PBR (the ``insignificance threshold,'' see below). 
If so, we consider M/SI from the specified activities to represent an 
insignificant incremental increase in ongoing anthropogenic M/SI for 
the marine mammal stock in question that alone (i.e., in the absence of 
any other take) will not adversely affect annual rates of recruitment 
and survival. As such, this amount of M/SI would not be expected to 
affect rates of recruitment or survival in a manner resulting in more 
than a negligible impact on the affected stock unless there are other 
factors that could affect reproduction or survival, such as Level A 
and/or Level B harassment, or other considerations such as information 
that illustrates the uncertainty involved in the calculation of PBR for 
some stocks. In a few prior incidental take rulemakings, this threshold 
was identified as the ``significance threshold,'' but it is more 
accurately labeled an insignificance threshold, and so we use that 
terminology here, as we did in the AFTT Proposed and Final Rules (83 FR 
57076; November 14, 2018). Assuming that any additional incidental take 
by Level A or Level B harassment from the activities in question would 
not combine with the effects of the authorized M/SI to exceed the 
negligible impact level, the anticipated M/SI caused by the activities 
being evaluated would have a negligible impact on the species or stock. 
However, M/SI above the 10 percent insignificance threshold does not 
indicate that the M/SI associated with the specified activities is 
approaching a level that would necessarily exceed negligible impact. 
Rather, the 10 percent insignificance threshold is meant only to 
identify instances where additional analysis of the anticipated M/SI is 
not required because the negligible impact standard clearly will not be 
exceeded on that basis alone.
    Where the anticipated M/SI is near, at, or above residual PBR, 
consideration of other factors (positive or negative), including those 
outlined above, as well as mitigation is especially important to 
assessing whether the M/SI will have a negligible impact on the species 
or stock. PBR is a conservative metric and not sufficiently precise to 
serve as an absolute predictor of population effects upon which 
mortality caps would appropriately be based. For example, in some cases 
stock abundance (which is one of three key inputs into the PBR 
calculation) is underestimated because marine mammal survey data within 
the

[[Page 66987]]

U.S. EEZ are used to calculate the abundance even when the stock range 
extends well beyond the U.S. EEZ. An underestimate of abundance could 
result in an underestimate of PBR. Alternatively, we sometimes may not 
have complete M/SI data beyond the U.S. EEZ to compare to PBR, which 
could result in an overestimate of residual PBR. The accuracy and 
certainty around the data that feed any PBR calculation, such as the 
abundance estimates, must be carefully considered to evaluate whether 
the calculated PBR accurately reflects the circumstances of the 
particular stock. M/SI that exceeds PBR may still potentially be found 
to be negligible in light of other factors that offset concern, 
especially when robust mitigation and adaptive management provisions 
are included.
    In Conservation Council for Hawaii v. National Marine Fisheries 
Service, which involved the challenge to NMFS' issuance of LOAs to the 
Navy in 2013 for activities in the HSTT Study Area, the Court reached a 
different conclusion, stating, ``Because any mortality level that 
exceeds PBR will not allow the stock to reach or maintain its OSP, such 
a mortality level could not be said to have only a `negligible impact' 
on the stock.'' As described above, the Court's statement fundamentally 
misunderstands the two terms and incorrectly indicates that these 
concepts (PBR and ``negligible impact'') are directly connected, when 
in fact nowhere in the MMPA is it indicated that these two terms are 
equivalent.
    Specifically, PBR was designed as a tool for evaluating mortality 
and is defined as the number of animals that can be removed while 
``allowing that stock to reach or maintain its [OSP].'' OSP is defined 
as a population that falls within a range from the population level 
that is the largest supportable within the ecosystem to the population 
level that results in maximum net productivity, and thus is an 
aspirational management goal of the overall statute with no specific 
timeframe by which it should be met. PBR is designed to ensure minimal 
deviation from this overarching goal, with the formula for PBR 
typically ensuring that growth towards OSP is not reduced by more than 
10 percent (or equilibrates to OSP 95 percent of the time). As PBR is 
applied by NMFS, it provides that growth toward OSP is not reduced by 
more than 10 percent, which certainly allows a stock to ``reach or 
maintain its [OSP]'' in a conservative and precautionary manner--and we 
can therefore clearly conclude that if PBR were not exceeded, there 
would not be adverse effects on the affected species or stocks. 
Nonetheless, it is equally clear that in some cases the time to reach 
this aspirational OSP level could be slowed by more than 10 percent 
(i.e., total human-caused mortality in excess of PBR could be allowed) 
without adversely affecting a species or stock through effects on its 
rates of recruitment or survival. Thus even in situations where the 
inputs to calculate PBR are thought to accurately represent factors 
such as the species' or stock's abundance or productivity rate, it is 
still possible for incidental take to have a negligible impact on the 
species or stock even where M/SI exceeds residual PBR or PBR.
    As noted above, in some cases the ongoing human-caused mortality 
from activities other than those being evaluated already exceeds PBR 
and, therefore, residual PBR is negative. In these cases (such as is 
specifically discussed for the Eastern North Pacific stock of blue 
whales and the CA/OR/WA stock of humpback whales), any additional 
mortality, no matter how small, and no matter how small relative to the 
mortality caused by other human activities, would result in greater 
exceedance of PBR. PBR is helpful in informing the analysis of the 
effects of mortality on a species or stock because it is important from 
a biological perspective to be able to consider how the total mortality 
in a given year may affect the population. However, section 
101(a)(5)(A) of the MMPA indicates that NMFS shall authorize the 
requested incidental take from a specified activity if we find that 
``the total of such taking [i.e., from the specified activity] will 
have a negligible impact on such species or stock.'' In other words, 
the task under the statute is to evaluate the applicant's anticipated 
take in relation to their take's impact on the species or stock, not 
other entities' impacts on the species or stock. Neither the MMPA nor 
NMFS' implementing regulations call for consideration of other 
unrelated activities and their impacts on the species or stock. In 
fact, in response to public comments on the implementing regulations 
NMFS explained that such effects are not considered in making 
negligible impact findings under section 101(a)(5), although the extent 
to which a species or stock is being impacted by other anthropogenic 
activities is not ignored. Such effects are reflected in the baseline 
of existing impacts as reflected in the species' or stock's abundance, 
distribution, reproductive rate, and other biological indicators.
    NMFS guidance for commercial fisheries provides insight when 
evaluating the effects of an applicant's incidental take as compared to 
the incidental take caused by other entities. Parallel to section 
101(a)(5)(A), section 101(a)(5)(E) of the MMPA provides that NMFS shall 
allow the incidental take of ESA-listed endangered or threatened marine 
mammals by commercial fisheries if, among other things, the incidental 
M/SI from the commercial fisheries will have a negligible impact on the 
species or stock. As discussed earlier, the authorization of incidental 
take resulting from commercial fisheries and authorization for 
activities other than commercial fisheries are under two separate 
regulatory frameworks. However when it amended the statute in 1994 to 
provide a separate incidental take authorization process for commercial 
fisheries, Congress kept the requirement of a negligible impact 
determination for this one category of species, thereby applying the 
standard to both programs. Therefore, while the structure and other 
standards of the two programs differ such that evaluation of negligible 
impact under one program may not be fully applicable to the other 
program (e.g., the regulatory definition of ``negligible impact'' at 50 
CFR 216.103 applies only to activities other than commercial fishing), 
guidance on determining negligible impact for commercial fishing take 
authorizations can be informative when considering incidental take 
outside the commercial fishing context. In 1999, NMFS published 
criteria for making a negligible impact determination pursuant to 
section 101(a)(5)(E) of the MMPA in a notice of proposed permits for 
certain fisheries (64 FR 28800; May 27, 1999). Criterion 2 stated ``If 
total human-related serious injuries and mortalities are greater than 
PBR, and fisheries-related mortality is less than 0.1 PBR, individual 
fisheries may be permitted if management measures are being taken to 
address non-fisheries-related serious injuries and mortalities. When 
fisheries-related serious injury and mortality is less than 10 percent 
of the total, the appropriate management action is to address 
components that account for the major portion of the total.'' This 
criterion addresses when total human-caused mortality is exceeding PBR, 
but the activity being assessed is responsible for only a small portion 
of the mortality. In the HSTT proposed rule and other incidental take 
authorizations in which NMFS has recently articulated a fuller 
description of how we consider PBR under section 101(a)(5)(A), this 
situation had not arisen, and NMFS' description of how we consider PBR 
in the section 101(a)(5) authorization process did not, therefore, 
include consideration of this scenario.

[[Page 66988]]

However, the analytical framework we use here appropriately 
incorporates elements of the one developed for use under section 
101(a)(5)(E) and because the negligible impact determination under 
section 101(a)(5)(A) focuses on the activity being evaluated, it is 
appropriate to utilize the parallel concept from the framework for 
section 101(a)(5)(E).
    Accordingly, we are using a similar criterion in our negligible 
impact analysis under section 101(a)(5)(A) to evaluate the relative 
role of an applicant's incidental take when other sources of take are 
causing PBR to be exceeded, but the take of the specified activity is 
comparatively small. Where this occurs, we may find that the impacts of 
the taking from the specified activity may (alone) be negligible even 
when total human-caused mortality from all activities exceeds PBR if 
(in the context of a particular species or stock): The authorized 
mortality or serious injury would be less than or equal to 10 percent 
of PBR and management measures are being taken to address serious 
injuries and mortalities from the other activities (i.e., other than 
the specified activities covered by the incidental take authorization 
under consideration). We must also determine, though, that impacts on 
the species or stock from other types of take (i.e., harassment) caused 
by the applicant do not combine with the impacts from mortality or 
serious injury to result in adverse effects on the species or stock 
through effects on annual rates of recruitment or survival.
    As discussed above, however, while PBR is useful in informing the 
evaluation of the effects of M/SI in section 101(a)(5)(A) 
determinations, it is just one consideration to be assessed in 
combination with other factors and is not determinative, including 
because, as explained above, the accuracy and certainty of the data 
used to calculate PBR for the species or stock must be considered. And 
we reiterate the considerations discussed above for why it is not 
appropriate to consider PBR an absolute cap in the application of this 
guidance. Accordingly, we use PBR as a trigger for concern while also 
considering other relevant factors to provide a reasonable and 
appropriate means of evaluating the effects of potential mortality on 
rates of recruitment and survival, while acknowledging that it is 
possible to exceed PBR (or exceed 10 percent of PBR in the case where 
other human-caused mortality is exceeding PBR but the specified 
activity being evaluated is an incremental contributor, as described in 
the last paragraph) by some small amount and still make a negligible 
impact determination under section 101(a)(5)(A).
    Our evaluation of the M/SI for each of the species and stocks for 
which mortality or serious injury could occur follows. No mortalities 
or serious injuries are anticipated from the Navy's sonar activities. 
In addition, all mortality authorized for some of the same species or 
stocks over the next several years pursuant to our final rulemaking for 
the NMFS Southwest and Pacific Islands Fisheries Science Centers has 
been incorporated into the residual PBR.
    We first consider maximum potential incidental M/SI from the Navy's 
ship strike analysis for the affected mysticetes and sperm whales (see 
Table 69) and from the Navy's explosive detonations for California sea 
lions and short-beaked common dolphin (see Table 70) in consideration 
of NMFS' threshold for identifying insignificant M/SI take. By 
considering the maximum potential incidental M/SI in relation to PBR 
and ongoing sources of anthropogenic mortality, we begin our evaluation 
of whether the potential incremental addition of M/SI through Navy's 
ship strikes and explosive detonations may affect the species' or 
stocks' annual rates of recruitment or survival. We also consider the 
interaction of those mortalities with incidental taking of that species 
or stock by harassment pursuant to the specified activity.
    Based on the methods discussed previously, NMFS believes that 
mortal takes of three large whales may occur over the course of the 
five-year rule. The rule authorizes no more than two from any of the 
following species/stocks over the five-year period: gray whale (Eastern 
North Pacific stock), fin whale (CA/OR/WA stock), and humpback whale 
(Central North Pacific stock). The rule authorizes no more than one 
mortality from any of the following species/stocks over the five-year 
period: blue whale (Eastern North Pacific stock), humpback whale (CA/
OR/WA stock, Mexico DPS), and sperm whale (Hawaii stock). We do not 
anticipate, nor authorize, ship strike takes to blue whale (Central 
North Pacific stock), fin whale (Hawaii stock), gray whale (Western 
North Pacific stock), minke whale (either CA/OR/WA stock or Hawaii 
stock), sei whale (either Hawaii stock or Eastern North Pacific stock), 
Bryde's whale (either Hawaii stock or Eastern Tropical Pacific stock) 
or sperm whale (CA/OR/WA stock). This means an annual average of 0.2 
whales from each species or stock where one mortality may occur and an 
annual average of 0.4 whales from each species or stock where two 
mortalities may occur as described in Table 69 (i.e., 1 or 2 takes over 
5 years divided by 5 to get the annual number) is authorized.

                                                    Table 69--Summary Information Related to Mortalities Requested for Ship Strike, 2018-2023
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Annual
                                                   authorized                                                                            Residual
                                        Stock       take by      Total     Fisheries interactions   Vessel collisions (Y/N);             PBR-PBR                             Recent UME (Y/N);
          Species (stock)             abundance     serious    annual M/  (Y/N); annual rate of M/  annual rate of M/SI from   PBR *      minus       Stock trend * \4\       number and year
                                      (Nbest) *    injury or    SI * \2\      SI from fisheries         vessel collision*              annual M/SI                              (since 2007)
                                                   mortality                   interactions *                                              \3\
                                                      \1\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Fin whale (CA/OR/WA stock).........        9,029          0.4     >=43.5  Y; >=0.5................  Y, 1.6..................       81         37.5  [uarr]...............  N.
Gray whale (Eastern North Pacific         26,960          0.4        138  Y, 7.7..................  Y, 0.8..................      801          663  stable since 2003....  N.
 stock).
Humpback whale (CA/OR/WA stock,            2,900          0.2     >=38.6  Y; >=14.1...............  Y, 22...................     16.7        -21.9  [uarr]...............  N.
 Mexico DPS).
Humpback whale (Central North             10,103          0.4      40.76  Y; 18.76................  Y, 22...................     33.4        -7.36  stable...............  N.
 Pacific stock).
Sperm whale (Hawaii stock).........        5,559          0.2        0.7  Y, 0.7..................  N.......................     13.9         13.2  ?....................  N.

[[Page 66989]]

 
Blue whale (Eastern North Pacific          1,647          0.2       >=19  >=0.96..................  Y, 18...................      2.3        -16.7  stable...............  Y; 3, 2007.
 Stock).
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
* Presented in the SARS.
\1\ This column represents the annual take by serious injury or mortality by vessel collision and was calculated by the number of mortalities for authorization divided by five years (the
  length of the rule and LOAs).
\2\ This column represents the total number of incidents of M/SI that could potentially accrue to the specified species or stock. This number comes from the SAR, but deducts the takes accrued
  from either Navy strikes or NMFS' Southwest Fisheries Science Center (SWFSC) takes in the SARs to ensure not double-counted against PBR. However, for these species, there were no takes from
  either other Navy activities or SWFSC in the SARs to deduct that would be considered double-counting.
\3\ This value represents the calculated PBR less the average annual estimate of ongoing anthropogenic mortalities (i.e., total annual human-caused M/SI, which is presented in the SARs).
\4\ See relevant SARs for more information regarding stock status and trends.

    The Navy has also requested a small number of takes by serious 
injury or mortality from explosives. To calculate the annual average of 
mortalities for explosives in Table 70 we used the same method as 
described for vessel strikes. The annual average is the total number of 
takes divided by five years to get the annual number. Specifically, 
NMFS is authorizing the following serious injury or mortality takes 
from explosions: 4 California sea lions and 6 short-beaked common 
dolphins over the 5-year period (therefore 0.8 mortalities annually for 
California sea lions and 1.2 mortalities annually for short-beaked 
common dolphin), as described in Table 70.

                                     Table 70--Summary Information Related to Mortalities From Explosives, 2018-2023
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                               Annual
                                             authorized                  Fisheries                   SWFSC       Residual
                                  Stock       take by      Total    interactions (Y/N);            authorized    PBR--PBR      Stock
       Species (stock)          abundance     serious    annual M/  annual rate of M/SI   PBR *       take        minus       trend *      UME (Y/N);
                                (Nbest) *    injury or    SI * \2\     from fisheries               (annual)   annual M/SI      \5\      number and year
                                            mortality *                interactions *                 \3\       and SWFSC
                                                \1\                                                                \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
California sea lion (U.S.          257,606          0.8      318.4  Y; 197.............   14,011          6.6       13,686     [uarr]   Y; 2013.
 stock).
Short-beaked common dolphin        969,861          1.2       >=40  Y; >=40............    8,393          2.8      8,350.2          ?   N.
 (CA/OR/WA stock).
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Presented in the SARS.
\1\ This column represents the annual take by serious injury or mortality during explosive detonations and was calculated by the number of mortalities
  planned for authorization divided by five years (the length of the rule and LOAs).
\2\ This column represents the total number of incidents of M/SI that could potentially accrue to the specified species or stock. This number comes from
  the SAR, but deducts the takes accrued from either Navy activities or NMFS' SWFSC takes in the SARs to ensure not double-counted against PBR. In this
  case, for California sea lion 0.8 annual M/SI from the U.S. West Coast during scientific trawl and longline operations conducted by NMFS and 1.8
  annual M/SI from marine mammal research related mortalities authorized by NMFS was deducted from total annual M/SI (321).
\3\ This column represents annual take authorized through NMFS' SWFSC rulemaking/LOAs (80 FR 58982).
\4\ This value represents the calculated PBR less the average annual estimate of ongoing anthropogenic mortalities (i.e., total annual human-caused M/SI
  column and the annual authorized take from the SWFSC column. In the case of California sea lion the M/SI column (318.4) and the annual authorized take
  from the SWFSC (6.6) were subtracted from the calculated PBR.of 14,011. In the case of Short-beaked common dolphin the M/SI column (40) and the annual
  authorized take from the SWFSC (2.8) were subtracted from the calculated PBR of 8,393.
\5\ See relevant SARs for more information regarding stock status and trends.

Stocks With M/SI Below the Insignificance Threshold

    As noted above, for a species or stock with incidental M/SI less 
than 10 percent of residual PBR, we consider M/SI from the specified 
activities to represent an insignificant incremental increase in 
ongoing anthropogenic M/SI that alone (i.e., in the absence of any 
other take and barring any other unusual circumstances) will clearly 
not adversely affect annual rates of recruitment and survival. In this 
case, as shown in Tables 69 and 70, the following species or stocks 
have potential or estimated (from ship strike and explosive takes, 
respectively), and authorized, M/SI below their insignificance 
threshold: fin whale (CA/OR/WA stock), gray whale (Eastern North 
Pacific stock), humpback whale (Central North Pacific stock), sperm 
whale (Hawaii stock), California sea lion (U.S stock), and short-beaked 
common dolphin (CA/OR/WA stock). While the authorized mortality of 
California sea lions (U.S. stock) are below the insignificance 
threshold, because of the recent UMEs, we further address how the 
authorized serious injury or mortality and the UME inform the 
negligible impact determination immediately below. For the other five 
stocks with authorized mortality below the insignificance threshold, 
there are no other known factors, information, or unusual circumstances 
that indicate anticipated M/SI below the insignificance threshold could 
have adverse effects on annual rates of recruitment or survival and 
they are not discussed further. For the remaining two stocks with 
anticipated potential M/SI above the insignificance threshold, how that 
M/SI compares to residual PBR, as well as additional factors, as 
appropriate, are discussed below as well.
California Sea Lion (U.S. Stock)
    The estimated (and authorized) lethal take of California sea lions 
is well below the insignificance threshold (0.8 as compared to a 
residual PBR of 13,686) and NMFS classifies the stock as ``increasing'' 
in the SARs. Nonetheless, we consider here how the 2013-present 
California Sea Lion Unusual Mortality Event informs our negligible 
impact determination. This UME was confined

[[Page 66990]]

to pup and yearling sea lions and many were emaciated, dehydrated, and 
underweight. Although this UME has not been closed, NMFS staff 
confirmed that the mortality of pups and yearlings returned to normal 
in 2017 and 2018 and we plan to present it to the Working Group to 
discuss closure by the end of 2018 (Deb Fauquier, pers. comm.). NMFS' 
findings to date indicate that a change in the availability of sea lion 
prey, especially sardines, a high value food source for nursing 
mothers, was a likely contributor to the large number of strandings. 
Sardine spawning grounds shifted further offshore in 2012 and 2013, and 
while other prey were available (market squid and rockfish), these may 
not have provided adequate nutrition in the milk of sea lion mothers 
supporting pups, or for newly-weaned pups foraging on their own. 
Although the pups showed signs of some viruses and infections, findings 
indicate that this event was not caused by disease, but rather by the 
lack of high quality, close-by food sources for nursing mothers. 
Average mortalities from 2013-2017 averaged about 1,000-3,000 more 
annually than they had in the previous 10 years. However, even if these 
unusual mortalities were still occurring (with current data suggesting 
they are not), combined with other annual human-caused mortalities, and 
viewed through the PBR lens (for human-caused mortalities), total 
human-caused mortality (inclusive of the potential for additional UME 
deaths) would still fall well below residual PBR. Further, the loss of 
pups and yearlings would not be expected to have as much of an effect 
on annual population rates as the death of adult females. In 
conclusion, because of the abundance, population trend, and residual 
PBR of this stock, as well as the fact that the increased mortality 
stopped two years ago and the UME is expected to be closed soon, this 
UME is not expected to have any impacts on individuals in the coming 
five years, nor is it thought to have had impacts on the population 
rate when it was occurring that would influence our evaluation of the 
effects of authorized mortality on the stock.

Stocks With M/SI Above Residual PBR

Humpback Whale (CA/OR/WA Stock, Mexico DPS)
    For this stock, PBR is currently set at 33.4 and the total annual 
M/SI is estimated at greater than or equal to 40.76, yielding a 
residual PBR of -7.36. NMFS is authorizing one serious injury or 
mortality over the five-year duration of the rule (indicated as 0.2 
annually for the purposes of comparing to PBR), which means that 
residual PBR is exceeded by 7.56. However, as described previously, in 
the commercial fisheries setting for ESA-listed marine mammals (which 
is similar to the non-fisheries incidental take setting, in that a 
negligible impact determination is required that is based on the 
assessment of take caused by the activity being analyzed) NMFS may find 
the impact of the authorized take from a specified activity to be 
negligible even if total human-caused mortality exceeds PBR, if the 
authorized mortality is less than 10 percent of PBR and management 
measures are being taken to address serious injuries and mortalities 
from the other activities causing mortality (i.e., other than the 
specified activities covered by the incidental take authorization in 
consideration). When those considerations are applied in the section 
101(a)(5)(A) context, the authorized lethal take (0.2 annually) of 
humpback whales from the CA/OR/WA stock is significantly less than 10 
percent of PBR (in fact less than 1 percent of 33.4) and there are 
management measures in place to address serious injury and mortality 
from activities other than those the Navy is conducting (summarized 
below).
    Based on identical simulations as those conducted to identify 
Recovery Factors for PBR in Wade et al. (1998), but where values less 
than 0.1 were investigated (P. Wade, pers. comm.), we predict that 
where the mortality from a specified activity does not exceed Nmin *1/2 
Rmax * 0.013, the contemplated mortality for the specific activity will 
not delay the time to recovery by more than 1 percent. For this stock 
of humpback whales, Nmin *1/2 Rmax * 0.013 = 1.45 and the annual 
authorized mortality is 0.2 (i.e., less than 1.45), which means that 
the mortality authorized in this rule for HSTT activities will not 
delay the time to recovery by more than 1 percent.
    As described previously, NMFS must also ensure that impacts by the 
applicant on the species or stock from other types of take (i.e., 
harassment) do not combine with the impacts from mortality and serious 
injury to adversely affect the species or stock via impacts on annual 
rates of recruitment or survival, which is discussed further below in 
the stock-specific conclusion sections.
    We discuss here the nature in which the predicted average annual 
mortality from other sources has changed since the proposed rule. The 
proposed rule included the information from the 2017 SAR, which 
indicated that PBR was 11 and the total observed annual average 
mortality was greater than or equal to 6.5 (one from vessel strikes and 
>5.5 from fisheries interactions). The total human-caused mortality did 
not exceed residual PBR, and our analysis, which considered other 
factors as well, concluded that lethal take, alone, from the Navy's 
activities would not have more than a negligible impact on humpback 
whales (CA/OR/WA stock, Mexico DPS) (we also went on to analyze the 
effects of the potential lethal take in conjunction with the estimated 
harassment take under the negligible impact standard). In August 2018, 
NMFS published draft 2018 SARs in which PBR increased to 33.4 and the 
predicted average annual mortality increased to greater than or equal 
to 40.76 (22 estimated from vessel collisions, >14.1 observed fisheries 
interactions, and 2.16 predicted fisheries interactions if unidentified 
entanglements are prorated based on a model based on known species 
entanglements). While the observed mortality from vessel strikes 
remains low at 2.1, the draft 2018 SAR relies on a new method to 
estimate annual deaths by ship strike utilizing an encounter theory 
model that combined species distribution models of whale density, 
vessel traffic characteristics, along with whale movement patterns 
obtained from satellite-tagged animals in the region to estimate 
encounters that would result in mortality (Rockwood et al., 2017). The 
model predicts 22 annual mortalities of humpback whales from vessel 
strikes. The authors (Rockwood et al., 2017) do not suggest that ship 
strike suddenly increased to 22 this year. In fact, the model is not 
specific to a year, but rather offers a generalized prediction of ship 
strike off the U.S. West Coast. Therefore, if the Rockwood et al. 
(2017) model is an accurate representation of vessel strike, then 
similar levels of ship strike have been occurring in past years as 
well. Put another way, if the model is correct, for some number of 
years total human-caused mortality has been significantly 
underestimated, and PBR has been similarly exceeded by a notable 
amount, and yet the CA/OR/WA stock of humpback whales is considered 
stable nevertheless. We note that as of the date this final rule was 
signed and transmitted to the Office of the Federal Register, the 
public comment period for the draft 2018 SAR was still open. This means 
that NMFS has not yet considered any comments that other experts and 
the public might have regarding the propriety of the model for 
identifying annual mortality in the SAR.
    The CA/OR/WA stock of humpback whales experienced a steady increase

[[Page 66991]]

from the 1990s through approximately 2008, and more recent estimates 
through 2014 indicate a leveling off of the population size. This stock 
is comprised of the feeding groups of three DPSs. Two DPSs associated 
with this stock are listed under the ESA as either endangered (Central 
America DPS) or threatened (Mexico DPS), while the third is not listed. 
The mortality authorized by this rule is for an individual from the 
Mexico DPS only. As described in the Final Rule Identifying 14 DPSs of 
the Humpback Whale and Revision of Species-Wide Listing (81 FR 62260, 
September 8, 2016), the Mexico DPS was initially proposed not to be 
listed as threatened or endangered, but the final decision was changed 
in consideration of a new abundance estimate using a new methodology 
that was more accurate (less bias from capture heterogeneity and lower 
coefficient of variation) and resulted in a lower abundance than was 
previously estimated. To be clear, the new abundance estimate did not 
indicate that the numbers had decreased, but rather, the more accurate 
new abundance estimate (3,264), derived from the same data but based on 
an integrated spatial multi-strata mark recapture model (Wade et al., 
2016) was simply notably lower than earlier estimates, which were 
6,000-7,000 from the SPLASH project (Calambokidis et al., 2008) or 
higher (Barlow et al., 20111). The updated abundance was still higher 
than 2,000, which is the Biological Review Team's (BRT) threshold 
between ``not likely to be at risk of extinction due to low abundance 
alone'' and ``increasing risk from factors associated with low 
abundance.'' Further, the BRT concluded that the DPS was unlikely to be 
declining because of the population growth throughout most of its 
feeding areas, in California/Oregon and the Gulf of Alaska, but they 
did not have evidence that the Mexico DPS was actually increasing in 
overall population size.
    As discussed, we also take into consideration management measures 
in place to address serious injury and mortality caused by other 
activities. The California swordfish and thresher shark drift gillnet 
fishery is one of the primary causes of M/SI take from fisheries 
interactions for humpback whales on the West Coast. NMFS established 
the Pacific Offshore Cetacean Take Reduction Team in 1996 and prepared 
an associated Plan (PCTRP) to reduce the risk of M/SI via fisheries 
interactions. In 1997, NMFS published final regulations formalizing the 
requirements of the PCTRP, including the use of pingers following 
several specific provisions and the employment of Skipper education 
workshops.
    Crab pot fisheries are also a significant source of mortality for 
humpback whales and, unfortunately, have increased mortalities over 
recent years. However, the draft 2018 SAR notes that a recent increase 
in disentanglement efforts has resulted in an increase in the fraction 
of cases that are reported as non-serious injuries as a result of 
successful disentanglement. More importantly, since 2015, NMFS has 
engaged in a multi-stakeholder process in California (including 
California State resource managers, fishermen, NGOs, and scientists) to 
identify and develop solutions and make recommendations to regulators 
and the fishing industry for reducing whale entanglements (see http://www.opc.ca.gov/whale-entanglementworking-group/), referred to as the 
Whale Entanglement Working Group. More recently, similar efforts to 
address the entanglement issue have also been initiated in Oregon and 
Washington. The Whale Entanglement Working Group has made significant 
progress since 2015 and is tackling the problem from multiple angles, 
including:

    [ssquf] Development of Fact Sheets and Best Practices for 
specific Fisheries issues (e.g., California Dungeness Crab Fishing 
BMPs, or the 2018-2019 Best Fishing Practices Guide);
    [ssquf] 2018-2019 Risk Assessment and Mitigation Program (RAMP) 
to support the state of California in working collaboratively with 
experts (fishermen, researchers, NGOs, etc.) to identify and assess 
elevated levels of entanglement risk and determine the need for 
management options to reduce risk of entanglement; and
    [ssquf] Support of pilot studies to test new fisheries 
technologies to reduce take (e.g., Exploring Ropeless Fishing 
Technologies for the California Dungeness Crab Fishery).

    The Working Group meets regularly, posts reports and annual 
recommendations, and makes all of their products and guidance documents 
readily accessible for the public. The April 2018 Working Group Report 
reports on the progress of the RAMP (though there is a separate RAMP 
report), summarized new ideas for Fisheries BMPs, and indicated next 
steps.
    We also note that on November 26, 2018, NMFS' West Coast Regional 
Office received a notice of intent from the California Department of 
Fish and Wildlife to apply for a Section 10 Incidental Take Permit 
under the ESA to address protected species interactions in certain 
California state-managed fixed gear fisheries. Any request for such a 
permit must include a Habitat Conservation Plan that specifies, among 
other things, what steps the applicant will take to minimize and 
mitigate the impacts, and the funding that will be available to 
implement such steps.
    Further regarding measures in place to reduce mortality from 
sources other than the Navy, the Channel Islands NMS staff coordinates, 
collects, and monitors whale sightings in and around the Whale Advisory 
Zone and the Channel Islands NMS region, which is within the area of 
highest strike mortality (90th percentile) for humpback whales on the 
U.S. West coast (Rockwood et al., 2017). The seasonally established 
Whale Advisory Zone spans from Point Arguello to Dana Point, including 
the Traffic Separation Schemes in the Santa Barbara Channel and San 
Pedro Channel. Vessels transiting the area from June through November 
are recommended to exercise caution and voluntarily reduce speed to 10 
kn or less for blue, humpback, and fin whales. Channel Island NMS 
observers collect information from aerial surveys conducted by NOAA, 
the U.S. Coast Guard, California Department of Fish and Game, and Navy 
chartered aircraft. Information on seasonal presence, movement, and 
general distribution patterns of large whales is shared with mariners, 
NMFS' Office of Protected Resources, the U.S. Coast Guard, the 
California Department of Fish and Game, the Santa Barbara Museum of 
Natural History, the Marine Exchange of Southern California, and whale 
scientists. Real time and historical whale observation data collected 
from multiple sources can be viewed on the Point Blue Whale Database.
    We also note that in this case, 0.2 M/SI annually means the 
potential for one mortality in one of the five years and zero 
mortalities in four of those five years. Therefore, the Navy would not 
be contributing to the total human-caused mortality at all in four of 
the five, or 80 percent, of the years covered by this rule. That means 
that even if a humpback whale from the CA/OR/WA stock were to be 
struck, in four of the five years there could be no effect on annual 
rates of recruitment or survival from Navy-caused M/SI. Additionally, 
as noted previously, the loss of a male would have far less, if any, of 
an effect on population rates and absent any information suggesting 
that one sex is more likely to be struck than another, one could 
reasonably assume that there is a 50 percent chance that the single 
strike authorized by this rule would be a male, thereby further 
decreasing the likelihood of impacts on the population

[[Page 66992]]

rate. In situations like this where potential M/SI is fractional, 
consideration must be given to the lessened impacts anticipated due to 
the absence of mortality or serious injury in four of the five years 
and due to the fact that a single strike could be a male. Lastly, we 
reiterate that PBR is a conservative metric and also not sufficiently 
precise to serve as an absolute predictor of population effects upon 
which mortality caps would appropriately be based. This is especially 
important given the minor difference between zero and one across the 
five-year period covered by this rule, which is the smallest 
distinction possible when considering mortality. Wade et al. (1998), 
authors of the paper from which the current PBR equation is derived, 
note that ``Estimating incidental mortality in one year to be greater 
than the PBR calculated from a single abundance survey does not prove 
the mortality will lead to depletion; it identifies a population worthy 
of careful future monitoring and possibly indicates that mortality-
mitigation efforts should be initiated.''
    The information included here illustrates that this humpback whale 
stock is stable, the potential (and authorized) mortality is well below 
10 percent (0.6 percent) of PBR, and management actions are in place to 
minimize both fisheries interactions and ship strike from other vessel 
activity in the one of the highest-risk areas for strikes. More 
specifically, although the total human-mortality exceeds PBR, the 
authorized mortality for the Navy's specified activities would 
incrementally contribute less than 1 percent of that and, further, 
given the fact that it would occur in only one of five years and could 
be comprised of a male (far less impactful to the population), the 
potential impacts on population rates are even less. Based on the 
presence of the factors described above, including consideration of the 
fact that the authorized mortality of 0.2 will not delay the time to 
recovery by more than 1 percent, we do not expect lethal take from Navy 
activities, alone, to adversely affect the CA/OR/WA stock of humpback 
whales through effects on annual rates of recruitment or survival. 
Nonetheless, the fact that total human-caused mortality exceeds PBR 
necessitates close attention to the remainder of the impacts (i.e., 
harassment) on the CA/OR/WA stock of humpback whales from the Navy's 
activities to ensure that the total authorized takes have a negligible 
impact on the species and stock. Therefore this information will be 
considered in combination with our assessment of the impacts of 
harassment takes later in the section, in the humpback whale conclusion 
section.
Blue Whale (Eastern North Pacific Stock)
    For blue whales (Eastern North Pacific stock), PBR is currently set 
at 2.3 and the total annual M/SI is estimated at greater than or equal 
to 19, yielding a residual PBR of -16.7. NMFS is authorizing one 
serious injury or mortality for the Navy over the five-year duration of 
the rule (indicated as 0.2 annually for the purposes of comparing to 
PBR), which means that residual PBR is exceeded by 16.9. However, as 
described previously, in the commercial fisheries setting for ESA-
listed marine mammals (which is similar to the incidental take setting, 
in that the negligible impact determination is based on the assessment 
of take of the activity being analyzed) NMFS may find the impact of the 
authorized take from a specified activity to be negligible even if 
total human-caused mortality exceeds PBR, if the authorized mortality 
is less than 10 percent of PBR and management measures are being taken 
to address serious injuries and mortalities from the other activities 
causing mortality (i.e., other than the specified activities covered by 
the incidental take authorization in consideration). When those 
considerations are applied in the section 101(a)(5)(A) context, the 
authorized lethal take (0.2 annually) of blue whales from the Eastern 
North Pacific stock is less than 10 percent of PBR (which is 2.3) and 
there are management measures in place to address serious injury and 
mortality from activities other than those the Navy is conducting 
(summarized below). Perhaps more importantly, the population is 
considered ``stable'' and, specifically, the available data suggests 
that the current number of ship strikes is not likely to have an 
adverse impact on the population, despite the fact that it exceeds PBR, 
with the Navy's minimal additional mortality of one whale in the five 
years not creating the likelihood of adverse impact. Immediately below, 
we explain the information that supports our finding that the Navy's 
authorized mortality is not expected to result in more than a 
negligible impact on this stock. As described previously, NMFS must 
also ensure that impacts by the applicant on the species or stock from 
other types of take (i.e., harassment) do not combine with the impacts 
from mortality to adversely affect the species or stock via impacts on 
annual rates of recruitment or survival, which occurs further below in 
the stock-specific conclusion sections.
    We discuss here the nature in which the predicted average annual 
mortality from other sources has changed since the proposed rule. The 
proposed rule included the information from the 2017 SAR, which 
indicated that PBR was 2.3 and the total observed annual average 
mortality (which was all from ship strike) was 0.9. There were no other 
observed sources of mortality, the total human-caused mortality did not 
exceed residual PBR, and our analysis, which considered other factors 
as well, concluded that lethal take, alone, from the Navy's activities 
would not have more than a negligible impact on blue whales (Eastern 
North Pacific stock) (we also went on to analyze the effects of the 
potential lethal take in conjunction with the estimated harassment take 
under the negligible impact standard). In August 2018, NMFS published 
draft 2018 SARs in which PBR remained at 2.3 and observed average 
annual mortality went down to 0.2 (from ship strike). However, the 
draft 2018 SAR relies on a new method to estimate annual deaths by ship 
strike utilizing an encounter theory model that combined species 
distribution models of whale density, vessel traffic characteristics, 
along with whale movement patterns obtained from satellite-tagged 
animals in the region to estimate encounters that would result in 
mortality (Rockwood et al., 2017). The model predicts 18 annual 
mortalities of blue whales from vessel strikes, which, with the 
additional M/SI of 0.96 from fisheries interactions, results in the 
current estimate of residual PBR being -16.7. We note that as of the 
date this final rule was signed and transmitted to the Office of 
Federal Register, the public comment period for the draft 2018 SAR was 
still open. This means that NMFS has not yet considered any comments 
that other experts and the public might have regarding the propriety of 
the model for identifying annual mortality in the SAR.
    Although NMFS' Permits and Conservation Division in the Office of 
Protected Resources has independently reviewed the new ship strike 
model and its results and agrees that it is appropriate for estimating 
blue whale mortality by ship strike on the U.S. West Coast, for 
analytical purposes we also note that if the historical method were 
used to predict vessel strike (i.e., using observed mortality by vessel 
strike, or 0.2, instead of 18), then total human-caused mortality 
including the Navy's potential take would not exceed PBR. We further 
note that the authors (Rockwood et al., 2017) do not suggest that ship 
strike suddenly increased to 18

[[Page 66993]]

this past year. In fact, the model is not specific to a year, but 
rather offers a generalized prediction of ship strike off the U.S. West 
Coast. Therefore, if the Rockwood et al. (2017) model is an accurate 
representation of vessel strike, then similar levels of ship strike 
have been occurring in past years as well. Put another way, if the 
model is correct, for some number of years total-human-caused mortality 
has been significantly underestimated and PBR has been similarly 
exceeded by a notable amount, and yet the Eastern North Pacific stock 
of blue whales remains stable nevertheless.
    NMFS' draft 2018 SAR states that the stock is ``stable'' and there 
is no indication of a population size increase in this blue whale 
population since the early 1990s. The lack of a species' or stock's 
population increase can have several causes, some of which are 
positive. The draft SAR further cites to Monnahan et al. (2015), which 
used a population dynamics model to estimate that the Eastern North 
Pacific blue whale population was at 97 percent of carrying capacity in 
2013 and to suggest that the observed lack of a population increase 
since the early 1990s was explained by density dependence, not impacts 
from ship strike. This would mean that this stock of blue whales shows 
signs of stability and is not increasing in population size because the 
population size is at or nearing carrying capacity for its available 
habitat. And, in fact, we note that this stable population has 
maintained this status throughout the years that Navy has consistently 
tested and trained at similar levels (with similar vessel traffic) in 
areas that overlap with blue whale occurrence.
    Monnahan et al. (2015) modeled vessel numbers, ship strikes, and 
the population of the Eastern North Pacific blue whale population from 
1905 out to 2050 using a Bayesian framework to incorporate informative 
biological information and assign probability distributions to 
parameters and derived quantities of interest. The authors tested 
multiple scenarios with differing assumptions, incorporated 
uncertainty, and further tested the sensitivity of multiple variables. 
Their results indicated that there is no immediate threat (i.e. through 
2050) to the population from any of the scenarios tested, which 
included models with 10 and 35 strike mortalities per year. Broadly, 
the authors concluded that, unlike other blue whale stocks, the Eastern 
North Pacific blue whales have recovered from 70 years of whaling and 
are in no immediate threat from ship strikes. They further noted that 
their conclusion conflicts with the depleted and strategic designation 
under the MMPA, as well as PBR specifically.
    As discussed, we also take into consideration management measures 
in place to address serious injury and mortality caused by other 
activities. The Channel Islands NMS staff coordinates, collects, and 
monitors whale sightings in and around the Whale Advisory Zone and the 
Channel Islands NMS region. Redfern et al. (2013) note that the most 
risky area for blue whales is the Santa Barbara Channel, where shipping 
lanes intersect with common feeding areas. The seasonally established 
Whale Advisory Zone spans from Point Arguello to Dana Point, including 
the Traffic Separation Schemes in the Santa Barbara Channel and San 
Pedro Channel. Vessels transiting the area from June through November 
are recommended to exercise caution and voluntarily reduce speed to 10 
kn or less for blue, humpback, and fin whales. Channel Island NMS 
observers collect information from aerial surveys conducted by NOAA, 
the U.S. Coast Guard, California Department of Fish and Game, and U.S. 
Navy chartered aircraft. Information on seasonal presence, movement, 
and general distribution patterns of large whales is shared with 
mariners, NMFS Office of Protected Resources, U.S. Coast Guard, 
California Department of Fish and Game, the Santa Barbara Museum of 
Natural History, the Marine Exchange of Southern California, and whale 
scientists. Real time and historical whale observation data collected 
from multiple sources can be viewed on the Point Blue Whale Database.
    We also note that in this case, 0.2 M/SI means one mortality in one 
of the five years and zero mortalities in four of those five years. 
Therefore, the Navy would not be contributing to the total human-caused 
mortality at all in four of the five, or 80 percent, of the years 
covered by this rule. That means that even if a blue whale were to be 
struck, in four of the five years there could be no effect on annual 
rates of recruitment or survival from Navy-caused M/SI. Additionally, 
as noted previously, the loss of a male would have far less, if any, of 
an effect on population rates and absent any information suggesting 
that one sex is more likely to be struck than another, one could 
reasonably assume that there is a 50 percent chance that the single 
strike authorized by this rule would be a male, thereby further 
decreasing the likelihood of impacts on the population rate. In 
situations like this where potential M/SI is fractional, consideration 
must be given to the lessened impacts anticipated due to the absence of 
mortality or serious injury in four of the five years and the fact that 
the single strike could be a male. Lastly, we reiterate that PBR is a 
conservative metric and also not sufficiently precise to serve as an 
absolute predictor of population effects upon which mortality caps 
would appropriately be based. This is especially important given the 
minor difference between zero and one across the five-year period 
covered by this rule, which is the smallest distinction possible when 
considering mortality. Wade et al. (1998), authors of the paper from 
which the current PBR equation is derived, note that ``Estimating 
incidental mortality in one year to be greater than the PBR calculated 
from a single abundance survey does not prove the mortality will lead 
to depletion; it identifies a population worthy of careful future 
monitoring and possibly indicates that mortality-mitigation efforts 
should be initiated.'' The information included here illustrates that 
this blue whale stock is stable, approaching carrying capacity, and has 
leveled off because of density-dependence, not human-caused mortality, 
in spite of what might be otherwise indicated from the calculated PBR. 
Further, potential (and authorized) mortality is below 10 percent of 
PBR and management actions are in place to minimize ship strike from 
other vessel activity in the one of the highest-risk areas for strikes. 
Based on the presence of the factors described above, we do not expect 
lethal take from Navy activities, alone, to adversely Eastern North 
Pacific blue whales through effects on recruitment or survival. 
Nonetheless, the fact that total human-caused mortality exceeds PBR 
necessitates close attention to the remainder of the impacts (i.e., 
harassment) on the Eastern Central Pacific stock of blue whales from 
the Navy's activities to ensure that the total authorized takes have a 
negligible impact on the species or stock. Therefore, this information 
will be considered in combination with our assessment of the impacts of 
harassment takes later in the section.
Group and Species-Specific/Stock-Specific Analyses
    The maximum amount and type of incidental take of marine mammals 
reasonably likely to occur and therefore authorized from exposures to 
sonar and other active acoustic sources and explosions during the five-
year training and testing period are shown in Tables 41 and 42 along 
with the discussion in the Estimated Take of Marine Mammals section on 
Vessel Strike and Explosives. The vast majority of predicted

[[Page 66994]]

exposures (greater than 99 percent) are expected to be Level B 
harassment (non-injurious TTS and behavioral reactions) from acoustic 
and explosive sources during training and testing activities at 
relatively low received levels.
    As noted previously, the estimated Level B harassment takes 
represent instances of take, not the number of individuals taken (the 
much lower and less frequent Level A harassment takes are far more 
likely to be associated with separate individuals), and in many cases 
some individuals are expected to be taken more than one time, while in 
other cases a portion of individuals will not be taken at all. Below, 
we compare the total take numbers (including PTS, TTS, and behavioral 
harassment) for stocks to their associated abundance estimates to 
evaluate the magnitude of impacts across the stock and to individuals. 
Specifically, when an abundance percentage comparison is below 100, it 
means that that percentage or less of the individuals in the stock will 
be affected (i.e., some individuals will not be taken at all), that the 
average for those taken is one day per year, and that we would not 
expect any individuals to be taken more than a few times in a year. 
When it is more than 100 percent, it means there will definitely be 
some number of repeated takes of individuals. For example, if the 
percentage is 300, the average would be each individual is taken on 
three days in a year if all were taken, but it is more likely that some 
number of individuals will be taken more than three times and some 
number of individuals fewer or not at all. While it is not possible to 
know the maximum number of days across which individuals of a stock 
might be taken, in acknowledgement of the fact that it is more than the 
average, for the purposes of this analysis, we assume a number 
approaching twice the average. For example, if the percentage of take 
compared to the abundance is 800, we estimate that some individuals 
might be taken as many as 16 times. Those comparisons are included in 
the sections below. For some stocks these numbers have been adjusted 
slightly (with these adjustments being in the single digits) since the 
proposed rule so as to more consistently apply this approach, but these 
minor changes did not change the analysis or findings.
    To assist in understanding what this analysis means, we clarify a 
few issues related to estimated takes and the analysis here. An 
individual that incurs a PTS or TTS take may sometimes, for example, 
also be behaviorally disturbed at the same time. As described in more 
detail previously, the degree of PTS, and the degree and duration of 
TTS, expected to be incurred from the Navy's activities are not 
expected to impact marine mammals such that their reproduction or 
survival could be affected. Similarly, data do not suggest that a 
single instance in which an animal accrues PTS or TTS and is also 
behaviorally harassed would result in impacts to reproduction or 
survival. Alternately, we recognize that if an individual is 
behaviorally harassed repeatedly for a longer duration and on 
consecutive days, effects could accrue to the point that reproductive 
success is jeopardized (as discussed below in the stock-specific 
conclusions). Accordingly, as described in the previous paragraph, in 
analyzing the number of takes and the likelihood of repeated and 
sequential takes (which could accrue to reproductive impacts), we 
consider the total takes, not just the behavioral harassment takes, so 
that individuals exposed to both TS and behavioral harassment are 
appropriately considered. We note that the same logic applies with the 
potential addition of behavioral harassment to tissue damage from 
explosives, the difference being that we do already consider the 
likelihood of reproductive impacts whenever tissue damage occurs. 
Further, the number of level A harassment takes by either PTS or tissue 
damage are so low compared to abundance numbers that it is considered 
highly unlikely that any individual would be taken at those levels more 
than once.
    Use of sonar and other transducers would typically be transient and 
temporary. The majority of acoustic effects to mysticetes from sonar 
and other active sound sources during testing and training activities 
would be primarily from ASW events. It is important to note that 
although ASW is one of the warfare areas of focus during MTEs, there 
are significant periods when active ASW sonars are not in use. 
Nevertheless, behavioral reactions are assumed more likely to be 
significant during MTEs than during other ASW activities due to the 
duration (i.e., multiple days) and scale (i.e., multiple sonar 
platforms) of the MTEs. On the less severe end, exposure to 
comparatively lower levels of sound at a detectably greater distance 
from the animal, for a few or several minutes, could result in a 
behavioral response such as avoiding an area that an animal would 
otherwise have moved through or fed in, or breaking off one or a few 
feeding bouts. More severe behavioral effects could occur when an 
animal gets close enough to the source to receive a comparatively 
higher level of sound, is exposed continuously to one source for a 
longer time, or is exposed intermittently to different sources 
throughout a day. Such effects might result in an animal having a more 
severe flight response and leaving a larger area for a day or more, or 
potentially losing feeding opportunities for a day. However, such 
severe behavioral effects are expected to occur infrequently.
    Occasional, milder behavioral reactions are unlikely to cause long-
term consequences for individual animals or populations, and even if 
some smaller subset of the takes are in the form of a longer (several 
hours or a day) and more severe responses, if they are not expected to 
be repeated over sequential days, impacts to individual fitness are not 
anticipated. Nearly all studies and experts agree that infrequent 
exposures of a single day or less are unlikely to impact an 
individual's overall energy budget (Farmer et al., 2018; Harris et al., 
2017; King et al., 2015; NAS 2017; New et al., 2014; Southall et al., 
2007; Villegas-Amtmann et al., 2015). When impacts to individuals 
increase in magnitude or severity such that either repeated and 
sequential higher severity impacts occur (the probability of this goes 
up for an individual the higher total number of takes it has) or the 
total number of moderate to more severe impacts increases 
substantially, especially if occurring across sequential days, then it 
becomes more likely that the aggregate effects could potentially 
interfere with feeding enough to reduce energy budgets in a manner that 
could impact reproductive success via longer cow-calf intervals, 
terminated pregnancies, or calf mortality. It is important to note that 
these impacts only accrue to females, which only comprise a portion of 
the population (typically approximately 50 percent). Based on energetic 
models, it takes energetic impacts of a significantly greater magnitude 
to cause the death of an adult marine mammal, and females will always 
terminate a pregnancy or stop lactating before allowing their health to 
deteriorate. Also, the death of an adult female has significantly more 
impact on population growth rates than reductions in reproductive 
success, and death of males has very little effect on population growth 
rates. However, as explained earlier, such severe impacts from the 
Navy's activities would be very infrequent and not likely to occur at 
all for most species and stocks. Even for those species or stocks where 
it is possible for a small number of females to experience reproductive 
effects, we explain below why there still will be no

[[Page 66995]]

effect on rates of recruitment or survival.
    The analyses below in some cases address species collectively if 
they occupy the same functional hearing group (i.e., low, mid, and 
high-frequency cetaceans and pinnipeds in water), share similar life 
history strategies, and/or are known to behaviorally respond similarly 
to acoustic stressors. Because some of these groups or species share 
characteristics that inform the impact analysis similarly, it would be 
duplicative to repeat the same analysis for each species or stock. In 
addition, animals belonging to each stock within a species typically 
have the same hearing capabilities and behaviorally respond in the same 
manner as animals in other stocks within the species. Thus, our 
analysis below considers the effects of Navy's activities on each 
affected stock even where discussion is organized by functional hearing 
group and/or information is evaluated at the species level. Where there 
are meaningful differences between stocks within a species that would 
further differentiate the analysis (e.g., the status of the stock or 
mitigation related to biologically important areas for the stock), they 
are either described within the section or the discussion for those 
species or stocks is included as a separate subsection. Specifically 
below, we first give broad descriptions of the mysticete, odontocete, 
and pinniped groups and then differentiate into further groups as 
appropriate.

Mysticetes

    This section builds on the broader discussion above and brings 
together the discussion of the different types and amounts of take that 
different stocks will incur, the applicable mitigation for each stock, 
and the status of the stocks to support the negligible impact 
determinations for each stock. We have already described above why we 
believe the incremental addition of the small number of low-level PTS 
takes will not have any meaningful effect towards inhibiting 
reproduction or survival. We have also described (above in this section 
and in the proposed rule, respectively, with no new applicable 
information received since publication of the proposed rule) the 
unlikelihood of any masking or habitat impacts having effects that 
would impact the reproduction or survival of any of the individual 
marine mammals affected by the Navy's activities. For mysticetes, there 
is no predicted tissue damage from explosives for any stock. Much of 
the discussion below focuses on the behavioral effects and the 
mitigation measures that reduce the probability or severity of effects 
in biologically important areas. Because there are multiple stock-
specific factors in relation to the status of the species, as well as 
mortality take for several stocks, at the end of the section we break 
out our findings for most stocks on a stock-specific basis, however we 
do consider five of the stocks in Hawaii with low-level impacts 
together.
    In Table 71 and Table 72 below, for mysticetes, we indicate the 
total annual mortality, Level A and Level B harassment, and a number 
indicating the instances of total take as a percentage of abundance.
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BILLING CODE 3510-22-C
    The majority of takes by harassment of mysticetes in the HSTT Study 
Area are caused by sources from the MF1 active sonar bin (which 
includes hull-mounted sonar) because they are high level, narrowband 
sources in the 1-10 kHz range, which intersect what is estimated to be 
the most sensitive area of hearing for mysticetes. They also are used 
in a large portion of exercises (see Table 1.5-5 in the Navy's 
application). Most of the takes (62 percent) from the MF1 bin in the 
HSTT Study Area would result from received levels between 154 and 172 
dB SPL, while another 35 percent would result from exposure between 172 
and 178 dB SPL. For the remaining active sonar bin types, the 
percentages are as follows: LF3 = 96 percent between 142 and 160 dB 
SPL, LF5 = 98 percent between 100 and 130 dB SPL, MF4 = 98 percent 
between 136 and 154 dB SPL, MF5 = 97 percent between 118 and 142 dB 
SPL, and HF4 = 98 percent between 100 and 148 dB SPL. These values may 
be derived from the information in Tables 6.4-8 through 6.4-12 in the 
Navy's rulemaking/LOA application (though they were provided directly 
to NMFS upon request). For mysticetes, explosive training and testing 
activities do not result in any Level B behavioral harassment, PTS from 
explosives is fewer than 3 for every stock, and the TTS takes from 
explosives comprise a small fraction (approximately 1-10 percent) of 
those caused by exposure to active sonar. There are only two Level B 
harassment takes of mysticetes by pile driving and airguns each, one 
gray whale and one blue whale for each activity type. Based on this 
information, the majority of the Level B behavioral harassment is 
expected to be of low to sometimes moderate severity and of a 
relatively shorter duration.
    Research and observations show that if mysticetes are exposed to 
sonar or other active acoustic sources they may react in a number of 
ways depending on the characteristics of the sound source, their 
experience with the sound source, and whether they are migrating or on 
seasonal feeding or breeding grounds. Behavioral reactions may include 
alerting, breaking off feeding dives and surfacing, diving or swimming 
away, or no response at all (DOD, 2017; Nowacek, 2007; Richardson, 
1995; Southall et al., 2007). Overall, mysticetes have been observed to 
be more reactive to acoustic disturbance when a noise source is located 
directly on their migration route. Mysticetes disturbed while migrating 
could pause their migration or route around the disturbance, while 
males en route to breeding grounds have been shown to be less 
responsive to disturbances. Although some may pause temporarily, they 
will resume migration shortly after the exposure ends. Animals 
disturbed while engaged in other activities such as feeding or 
reproductive behaviors may be more likely to ignore or tolerate the 
disturbance and continue their natural behavior patterns. Alternately, 
adult females with calves may be more responsive to stressors. As noted 
in the Potential Effects of Specified Activities on Marine Mammals and 
Their Habitat section, there are multiple examples from behavioral 
response studies of odontocetes ceasing their feeding dives when 
exposed to sonar pulses at certain levels, but alternately, blue whales 
were less likely to show a visible response to sonar exposures at 
certain levels when feeding than when traveling. However, Goldbogen et 
al. (2013) indicated some horizontal displacement of deep foraging blue 
whales in response to simulated MFA sonar. Most Level B behavioral 
harassment of mysticetes is likely to be short-term and low to moderate 
severity, with no anticipated effect on reproduction or survival from 
Level B harassment.
    Richardson et al. (1995) noted that avoidance (temporary 
displacement of an individual from an area) reactions are the most 
obvious manifestations of disturbance in marine mammals. Avoidance is 
qualitatively different from the startle or flight response, but also 
differs in the magnitude of the response (i.e., directed movement, rate

[[Page 66997]]

of travel, etc.). Oftentimes avoidance is temporary, and animals return 
to the area once the noise has ceased. Some mysticetes may avoid larger 
activities such as a MTE as it moves through an area, although these 
activities do not typically use the same training locations day-after-
day during multi-day activities, except periodically in instrumented 
ranges. Therefore, displaced animals could return quickly after the MTE 
finishes. Due to the limited number and geographic scope of MTEs, it is 
unlikely that most mysticetes would encounter a major training exercise 
more than once per year and additionally, total hull-mounted sonar 
hours are limited in several areas that are important to mysticetes 
(described below). In the ocean, the use of sonar and other active 
acoustic sources is transient and is unlikely to expose the same 
population of animals repeatedly over a short period of time, 
especially given the broader-scale movements of mysticetes.
    The implementation of procedural mitigation and the sightability of 
mysticetes (due to their large size) further reduces the potential for 
a significant behavioral reaction or a threshold shift to occur (i.e., 
shutdowns are expected to be successfully implemented), though we have 
analyzed the impacts that are anticipated to occur and that we are 
therefore authorizing.
    As noted previously, when an animal incurs a threshold shift, it 
occurs in the frequency from that of the source up to one octave above. 
This means that the vast majority of threshold shifts caused by Navy 
sonar sources will typically occur in the range of 2-20 kHz (from the 
1-10 kHz MF1 bin, though in a specific narrow band within this range as 
the sources are narrowband), and if resulting from hull-mounted sonar, 
will be in the range of 3.5-7 kHz. The majority of mysticete 
vocalizations occur in frequencies below 1 kHz, which means that TTS 
incurred by mysticetes will not interfere with conspecific 
communication. Additionally, many of the other critical sounds that 
serve as cues for navigation and prey (e.g., waves, fish, 
invertebrates) occur below a few kHz, which means that detection of 
these signals will not be inhibited by most threshold shift either. 
When we look in ocean areas where the Navy has been intensively 
training and testing with sonar and other active acoustic sources for 
decades, there is no data suggesting any long-term consequences to 
reproduction or survival rates of mysticetes from exposure to sonar and 
other active acoustic sources.
    The Navy will also limit activities and employ other measures in 
mitigation areas that will avoid or reduce impacts to mysticetes and 
where BIAs for large whales have been identified in the HSTT Study 
Area.
    In the SOCAL portion of the HSTT Study Area, the Navy will 
implement the San Diego Arc, San Nicolas Island, and Santa Monica/Long 
Beach Mitigation Areas from June 1 through October 31, which will 
reduce impacts primarily to blue whales, but also potentially gray 
whales and fin whales. These mitigation areas fully overlap the three 
associated blue whale Feeding Areas (all three of which are BIAs) in 
the HSTT Study Area both temporally and spatially (see also the HSTT 
FEIS/OEIS Appendix K (Geographic Mitigation Assessment), Section K.4); 
only the Tanner-Cortes Bank BIA is not included for practicability 
reasons discussed previously. Within these three Mitigation Areas, the 
Navy will not exceed 200 hrs of MFAS sensor MF1 use (with the exception 
of active sonar maintenance and systems checks) in all three of the 
areas combined, annually, and will not use explosives during large-
caliber gunnery, torpedo, bombing, and missile (including 2.75-inch 
(in) rockets) activities during training (or for mine warfare in the 
San Nicolas and Santa Monica areas).
    In addition, the Navy will implement the year-round Santa Barbara 
Island Mitigation Area, which encompasses the portion of the Channel 
Islands NMS that overlaps with the HSTT Study Area. The Navy will not 
use MFAS sensor MF1 surface hull-mounted sonar or explosives used in 
gunnery (all calibers), torpedo, bombing, and missile exercises 
(including 2.75-in rockets) during training. This Mitigation area 
overlaps a blue whale feeding BIA and also the Channel Islands NMS is 
consider a highly productive and diverse area of high-value habitat 
that is more typically free of anthropogenic stressors, and, therefore, 
limiting activities in this area is considered habitat protection for 
the myriad marine mammal species that use it or may pass through the 
area.
    In the HRC portion of the HSTT Study Area, the Navy will implement 
the 4-Islands Region Mitigation Area, which is expected to reduce 
impacts to humpback whales (during an important breeding/calving time 
period), as well as the Main Hawaiian Island Insular stock of false 
killer whale, monk seals, and several dolphin species. In this area, 
the Navy will not use MFAS sensor MF1 during training or testing 
activities from November 15 through April 15 nor will the Navy use any 
explosives throughout the year that could potentially result in takes 
of marine mammals. Since 2009, the Navy has adhered to a Humpback Whale 
Cautionary Area as a mitigation area within the Hawaiian Islands 
Humpback Whale NMS, an area identified as having one of the highest 
concentrations of humpback whales, with calves, during the critical 
winter months. As added protection, the Navy has expanded the size and 
extended the season of the current Humpback Whale Cautionary Area, 
renaming this area the 4-Islands Region Mitigation Area to reflect the 
benefits afforded to multiple species. The season is currently between 
December 15 and April 15 and the Navy has extended it from November 15 
through April 15 for the purposes of this mitigation because the peak 
humpback whale season has expanded. The size of the 4-Islands Region 
Mitigation Area has also expanded since the last HSTT regulation to 
include an area north of Maui and Molokai and overlaps an area 
identified as a BIA for the endangered Main Hawaiian Islands insular 
false killer whales (Baird et al., 2015; Van Parijs, 2015) (see Figure 
5.4-3, in Chapter 5 Mitigation Areas for Marine Mammals in the Hawaii 
Range Complex of the HSTT FEIS/OEIS).
    Within the 4-Islands Region Mitigation Area is the Hawaiian Islands 
Humpback Whale Reproduction Area BIA (4-Islands Region and Penguin 
Bank). The use of sonar and other transducers primarily occur farther 
offshore than the delineated boundaries of the Hawaiian Islands 
Humpback Whale Reproduction Area BIA. Explosive events are typically 
conducted in areas that are designated for explosive use, which are 
areas outside of the Hawaiian Islands Humpback Whale Reproduction Area 
BIA.
    The restrictions on MFAS sensor MF1 in this area and the fact that 
the Navy does not plan to use any explosives in this area mean that the 
number of takes of humpback whales will be lessened, as will their 
potential severity, in that the Navy is avoiding exposures in an area 
and time where the takes would be more likely to interfere with cow/
calf communication or result in potentially heightened impacts on 
sensitive or na[iuml]ve individuals (calves).
    The Navy is also implementing the Hawaii Island Mitigation Area. 
The Hawaii Island Mitigation Area is effective year-round and the Navy 
will not use more than 300 hrs of MFAS sensory MF1 and will not exceed 
20 hrs of MFAS sensory MF4. Also within the Hawaii Island Mitigation 
Area, the Navy will not use any explosives (e.g., surface-to-surface or 
air-to-surface

[[Page 66998]]

missile and gunnery events, BOMBEX, and mine neutralization) during 
testing and training year-round. Of note here, this measure would 
provide additional protection in this important reproductive area for 
humpback whales, reducing impacts in an area and time where impacts 
would likely be more severe if incurred. Separately (and addressed more 
later), these protected areas also reduce impacts for identified 
biologically important areas for endangered Main Hawaiian Islands 
insular false killer whales, two species of beaked whales (Cuvier and 
Blainville's), dwarf sperm whale, pygmy killer whale, melon-headed 
whale, short-finned pilot whale, and several small resident populations 
of dolphins (Baird et al., 2015; Van Parijs, 2015).
    The 4-Islands Region Mitigation Area and the Hawaii Island 
Mitigation Area both also overlap with portions (approximately 55 
percent) of the Hawaiian Islands Humpback Whale NMS. The Navy will 
continue to issue an annual humpback whale awareness notification 
message to remind ships and aircraft to be extra vigilant during times 
of high densities of humpback whales while in transit and to maintain 
certain distances from animals during the operation of ships and 
aircraft.
    Below we compile and summarize the information that supports our 
determination that the Navy's activities will not adversely impact 
rates of recruitment or survival for any of the affected mysticete 
stocks:
    Blue Whale (Eastern North Pacific stock)--The SAR identifies this 
stock as ``stable'' even though the larger species is listed as 
endangered under the ESA. We further note that this stock was 
originally listed under the ESA as a result of the impacts from 
commercial whaling, which is no longer affecting the species. As 
discussed above, both the abundance and PBR are likely underestimated 
to some degree in the SAR. NMFS will authorize one mortality over the 
five years covered by this rule, or 0.2 mortality annually. With the 
addition of this 0.2 annual mortality, residual PBR is exceeded, 
resulting in the total human-caused mortality exceeding PBR by 16.9. 
However, as described in more detail above in the Serious Injury and 
Mortality subsection, when total human-caused mortality exceeds PBR, we 
consider whether the incremental addition of a small amount of 
authorized mortality from the specified activity may still result in a 
negligible impact, in part by identifying whether it is less than 10 
percent of PBR. In this case, the authorized mortality is well below 10 
percent of PBR, management measures are in place to reduce mortality 
from other sources, and the incremental addition of a single mortality 
over the course of the five-year Navy rule is not expected to, alone, 
lead to adverse impacts on the stock through effects on annual rates of 
recruitment or survival.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), the number of estimated total instances of take 
compared to the abundance (measured against both the Navy-estimated 
abundance and the SAR) is 253 and 121 percent, respectively (Table 72). 
Given the range of blue whales, this information suggests that only 
some portion of individuals in the stock are likely impacted, but that 
there will likely be some repeat exposure (maybe 5 or 6 days within a 
year) of some subset of individuals that spend extended time within the 
SOCAL Range. Regarding the severity of those individual takes by Level 
B behavioral harassment, we have explained that the duration of any 
exposure is expected to be between minutes and hours (i.e., relatively 
short) and the received sound levels largely below 172 dB with a 
portion up to 178 dB (i.e., of a moderate or lower level, less likely 
to evoke a severe response). Additionally, the Navy implements time/
area mitigation in SOCAL in the majority of the BIAs, which will reduce 
the severity of impacts to blue whales by reducing interference in 
feeding that could result in lost feeding opportunities or necessitate 
additional energy expenditure to find other good opportunities. 
Regarding the severity of TTS takes, we have explained that they are 
expected to be low-level, of short duration, and mostly not in a 
frequency band that would be expected to interfere with blue whale 
communication or other important low-frequency cues--and that the 
associated lost opportunities and capabilities are not at a level that 
would impact reproduction or survival. For similar reasons (described 
above) the single estimated Level A harassment take by PTS for this 
stock is unlikely to have any effect on the reproduction or survival of 
that one individual, even if it were to be experienced by an animal 
that also experiences one or more Level B harassment behavioral 
disruptions.
    Altogether, only a small portion of the stock is impacted and any 
individual blue whale is likely to be disturbed at a low-moderate 
level, with likely many animals exposed only once or twice and a subset 
potentially disturbed across five or six days, but minimized in 
biologically important areas. This low magnitude and severity of 
harassment effects is not expected to result in impacts on the 
reproduction or survival of any individuals and, therefore, when 
combined with the authorized mortality (which our earlier analysis 
indicated would not, alone, have more than a negligible impact on this 
stock of blue whales), the total take is not expected to adversely 
affect this stock through impacts on annual rates of recruitment or 
survival. For these reasons, we have determined, in consideration of 
all of the effects of the Navy's activities combined, that the 
authorized take will have a negligible impact on the Eastern North 
Pacific stock of blue whales.
    Bryde's whale (Eastern Tropical Pacific stock)--Little is known 
about this stock, or its status, and it is not listed under the ESA. No 
mortality or Level A harassment is anticipated or authorized. Regarding 
the magnitude of Level B harassment takes (TTS and behavioral 
disruption), the number of estimated total instances of take compared 
to the abundance is 3,154 percent, however, the abundance upon which 
this percentage is based (1.3 whales from the Navy estimate, which is 
extrapolated from density estimates based on very few sightings) is 
clearly erroneous and the SAR does not include an abundance estimate 
because all of the survey data is outdated (Table 72). However, the 
abundance in the early 1980s was estimated as 22,000 to 24,000, a 
portion of the stock was estimated at 13,000 in 1993, and the minimum 
number in the Gulf of California was estimated at 160 in 1990. Given 
this information and the fact that 41 total takes of Bryde's whales 
were estimated, this information suggests that only a small portion of 
the individuals in the stock are likely impacted, and few, if any, are 
likely taken over more than one day. Regarding the severity of those 
individual takes by Level B behavioral harassment, we have explained 
that the duration of any exposure is expected to be between minutes and 
hours (i.e., relatively short) and the received sound levels largely 
below 172 dB with a portion up to 178 dB (i.e., of a moderate or lower 
level, less likely to evoke a severe response). Regarding the severity 
of TTS takes, we have explained that they are expected to be low-level, 
of short duration, and mostly not in a frequency band that would be 
expected to interfere with Bryde's whale communication or other 
important low-frequency cues. Any associated lost opportunities and 
capabilities are not at a level that would impact reproduction or 
survival.
    Altogether, only a small portion of the stock is impacted and any 
individual Bryde's whale is likely to be disturbed at a low-moderate 
level, with few, if

[[Page 66999]]

any, individuals exposed over more than one day in the year. This low 
magnitude and severity of harassment effects is not expected to result 
in impacts on individual reproduction or survival, much less annual 
rates of recruitment or survival. For these reasons, we have 
determined, in consideration of all of the effects of the Navy's 
activities combined, that the authorized take will have a negligible 
impact on the Eastern Tropical Pacific stock of Bryde's whales.
    Fin whale (CA/OR/WA stock)--The SAR identifies this stock as 
``increasing,'' even though the larger species is listed as endangered 
under the ESA. NMFS will authorize two mortalities over the five years 
covered by this rule, or 0.4 mortality annually. The addition of this 
0.4 annual mortality still leaves the total human-caused mortality well 
under residual PBR.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), the number of estimated total instances of take 
compared to the abundance (measured against both the Navy-estimated 
abundance and the SAR) is 613 and 25 percent, respectively (Table 72). 
This information suggests that only some portion (less than 25 percent) 
of individuals in the stock are likely impacted, but that there is 
likely some repeat exposure (perhaps up to 12 days within a year) of 
some subset of individuals that spend extended time within the SOCAL 
complex. Some of these takes could occur on a few sequential days for 
some small number of individuals, for example, if they resulted from a 
multi-day exercise on a range while individuals were in the area for 
multiple days feeding. Regarding the severity of those individual takes 
by Level B behavioral harassment, we have explained that the duration 
of any exposure is expected to be between minutes and hours (i.e., 
relatively short) and the received sound levels largely below 172 dB 
with a portion up to 178 dB (i.e., of a moderate or lower level, less 
likely to evoke a severe response). Additionally, while there are no 
designated BIAs for fin whales in the SOCAL range, the Navy implements 
time/area mitigation in SOCAL in blue whale BIAs, and fin whales are 
known to sometimes feed in some of the same areas, which means they 
could potentially accrue some benefits from the mitigation. Regarding 
the severity of TTS takes, we have explained that they are expected to 
be low-level, of short duration, and mostly not in a frequency band 
that would be expected to interfere with fin whale communication or 
other important low-frequency cues--and that the associated lost 
opportunities and capabilities are not at a level that would impact 
reproduction or survival. For similar reasons (described above) the 
single estimated Level A harassment take by PTS for this stock is 
unlikely to have any effects on the reproduction or survival of that 
one individual.
    Altogether, this population is increasing, only a small portion of 
the stock is impacted, and any individual fin whale is likely to be 
disturbed at a low-moderate level, with the taken individuals likely 
exposed between one and twelve days, with a few individuals potentially 
taken on a few sequential days. This low magnitude and severity of 
harassment effects is not expected to result in impacts on individual 
reproduction or survival, nor are these harassment takes combined with 
the authorized mortality expected to adversely affect this stock 
through impacts on annual rates of recruitment or survival. For these 
reasons, we have determined, in consideration of all of the effects of 
the Navy's activities combined, that the authorized take will have a 
negligible impact on the CA/OR/WA stock of fin whales.
    Humpback whale (CA/OR/WA stock)--The SAR identifies this stock as 
stable (having shown a long-term increase from 1990 and then leveling 
off between 2008 and 2014) and the individuals in this stock are 
associated with three DPSs, one of which is not listed under the ESA 
(Hawaii), one of which is designated as threatened (Mexico), and one of 
which is designated as endangered (Central America) (individuals 
encountered in the SOCAL portion of the HSTT Study Area are likely to 
come from the latter two). NMFS will authorize one mortality over the 
five years covered by this rule, or 0.2 mortality annually (Mexico DPS 
only). With the addition of this 0.2 annual mortality, the total human-
caused mortality exceeds PBR by 7.56. However, as described in more 
detail above in the Serious Injury and Mortality subsection, when total 
human-caused mortality exceeds PBR, we consider whether the incremental 
addition of a small amount of authorized mortality from the specified 
activity may still result in a negligible impact, in part by 
identifying whether it is less than 10 percent of PBR, which is 33.4. 
In this case, the authorized mortality is well below 10 percent of PBR 
(less than one percent, in fact) and management measures are in place 
to reduce mortality from other sources. More importantly, as described 
above in Serious Injury and Mortality, the authorized mortality of 0.2 
will not delay the time to recovery by more than 1 percent. Given these 
factors, the incremental addition of a single mortality over the course 
of the five-year Navy rule is not expected to, alone, lead to adverse 
impacts on the stock through effects on annual rates of recruitment or 
survival.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), the number of estimated total instances of take 
compared to the abundance (measured against both the Navy-estimated 
abundance and the SAR) is 808 and 104 percent, respectively (Table 72). 
Given the range of humpback whales, this information suggests that only 
some portion of individuals in the stock are likely impacted, but that 
there is likely some repeat exposure (maybe perhaps up to 16 days 
within a year) of some subset of individuals that spend extended time 
within the SOCAL complex. Regarding the severity of those individual 
takes by Level B behavioral harassment, we have explained that the 
duration of any exposure is expected to be between minutes and hours 
(i.e., relatively short) and the received sound levels largely below 
172 dB with a portion up to 178 dB (i.e., of a moderate or lower level, 
less likely to evoke a severe response). Some of these takes could 
occur on several sequential days for some small number of individuals, 
for example, if they resulted from a multi-day exercise on a range 
while individuals were in the area for multiple days feeding, however, 
in these amounts it would still not be expected to adversely impact 
reproduction or survival of any individuals.
    Regarding the severity of TTS takes, we have explained that they 
are expected to be low-level, of short duration, and mostly not in a 
frequency band that would be expected to interfere with humpback whale 
communication or other important low-frequency cues--and that the 
associated lost opportunities and capabilities are not at a level that 
would impact reproduction or survival. For similar reasons (described 
above) the single estimated Level A harassment take by PTS for this 
stock is unlikely to have any effects on the reproduction or survival 
of that one individual.
    Altogether, only a small portion of the stock is impacted and any 
individual humpback whale is likely to be disturbed at a low-moderate 
level, with likely many animals exposed only once or twice and a subset 
potentially disturbed up to 16 days, but with no reason to think that 
more than a few of those days would be sequential. This low magnitude 
and severity of harassment effects is not expected to

[[Page 67000]]

result in impacts on the reproduction or survival of any individuals 
and, therefore, when combined with the authorized mortality (which our 
earlier analysis indicated would not, alone, have more than a 
negligible impact on this stock of humpback whales), the total take is 
not expected to adversely affect this stock through impacts on annual 
rates of recruitment or survival. For these reasons, we have 
determined, in consideration of all of the effects of the Navy's 
activities combined, that the authorized take will have a negligible 
impact on the CA/OR/WA stock of humpback whales.
    Minke whale (CA/OR/WA stock)--The status of this stock is unknown 
and it is not listed under the ESA. No mortality from vessel strike or 
tissue damage from explosive exposure is anticipated or authorized for 
this species. Regarding the magnitude of Level B harassment takes (TTS 
and behavioral disruption), the number of estimated total instances of 
take compared to the abundance (measured against both the Navy-
estimated abundance and the SAR) is 568 and 146 percent, respectively 
(Table 72). Based on the behaviors of minke whales, which often occur 
along continental shelves and sometimes establish home ranges along the 
West Coast, this information suggests that only a portion of 
individuals in the stock are likely impacted, but that there is likely 
some repeat exposure (perhaps up to 11 days within a year) of some 
subset of individuals that spend extended time within the SOCAL 
complex. Some of these takes could occur on a few sequential days for 
some small number of individuals, for example, if they resulted from a 
multi-day exercise on a range while individuals were in the area for 
multiple days feeding. Regarding the severity of those individual takes 
by Level B behavioral harassment, we have explained that the duration 
of any exposure is expected to be between minutes and hours (i.e., 
relatively short) and the received sound levels largely below 172 dB 
with a portion up to 178 dB (i.e., of a moderate or lower level, less 
likely to evoke a severe response). Regarding the severity of TTS 
takes, we have explained that they are expected to be low-level, of 
short duration, and mostly not in a frequency band that would be 
expected to interfere with minke whale communication or other important 
low-frequency cues--and that the associated lost opportunities and 
capabilities are not at a level that would impact reproduction or 
survival. For similar reasons (described above) the single estimated 
Level A harassment take by PTS for this stock is unlikely to have any 
effects on the reproduction or survival of any individuals.
    Altogether, only a portion of the stock is impacted and any 
individual minke whale is likely to be disturbed at a low-moderate 
level, with the taken individuals likely exposed between one and eleven 
days, with a few individuals potentially taken on a few sequential 
days. This low magnitude and severity of harassment effects is not 
expected to result in impacts on individual reproduction or survival, 
much less annual rates of recruitment or survival. For these reasons, 
we have determined, in consideration of all of the effects of the 
Navy's activities combined, that the authorized take will have a 
negligible impact on the CA/OR/WA stock of minke whales.
    Sei whale (Eastern North Pacific stock)--The status of this stock 
is unknown and it is listed under the ESA. No mortality or Level A 
harassment is anticipated or authorized. Regarding the magnitude of 
Level B harassment takes (TTS and behavioral disruption), the number of 
estimated total instances of take compared to the abundance (measured 
against both the Navy-estimated abundance and the SAR) is 2,633 and 15 
percent, respectively (Table 72), however, the abundance upon which the 
Navy percentage is based (3 from the Navy estimate, which is 
extrapolated from density estimates based on very few sightings) is 
likely an underestimate of the number of individuals in the HSTT study 
Area, resulting in an overestimated percentage. Nonetheless, even given 
this information and the large range of sei whales, and the fact that 
only 79 total Level B harassment takes of sei whales were estimated, it 
is likely that some very small number of sei whales is taken 
repeatedly, potentially up to 15 days in a year (typically 2,633 
percent would lead to the estimate of 52 days/year, however, given that 
there are only 79 sei whale total takes, we used the conservative 
assumption that five individuals might be taken up to 15 times, with 
the few remaining takes distributed among other individuals). Regarding 
the severity of those individual takes by Level B behavioral 
harassment, we have explained that the duration of any exposure is 
expected to be between minutes and hours (i.e., relatively short) and 
the received sound levels largely below 172 dB with a portion up to 178 
dB (i.e., of a moderate or lower level, less likely to evoke a severe 
response). Some of these takes could occur on a few sequential days for 
some small number of individuals, for example, if they resulted from a 
multi-day exercise on a range while individuals were in the area for 
multiple days feeding, however, in these amounts it would still not be 
expected to adversely impact reproduction or survival of any 
individuals. Regarding the severity of TTS takes, we have explained 
that they are expected to be low-level, of short duration, and mostly 
not in a frequency band that would be expected to interfere with sei 
whale communication or other important low-frequency cues--and that the 
associated lost opportunities and capabilities are not at a level that 
would impact reproduction or survival.
    Altogether, only a small portion of the stock is impacted and any 
individual sei whale is likely to be disturbed at a low-moderate level, 
with only a few individuals exposed over one to 15 days in a year, with 
no more than a few sequential days. This low magnitude and severity of 
harassment effects is not expected to result in impacts on individual 
reproduction or survival, much less annual rates of recruitment or 
survival. For these reasons, we have determined, in consideration of 
all of the effects of the Navy's activities combined, that the 
authorized take will have a negligible impact on the Eastern North 
Pacific stock of sei whales.
    Gray whale (Eastern North Pacific stock)--The SAR identifies this 
stock as ``increasing'' and the species is not listed under the ESA. 
NMFS will authorize two mortalities over the five years covered by this 
rule, or 0.4 mortality annually. The addition of this 0.4 annual 
mortality still leaves the total human-caused mortality well under the 
insignificance threshold of residual PBR.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), the number of estimated total instances of take 
compared to the abundance (measured against both the Navy-estimated 
abundance and the SAR) is 2,424 and 22 percent, respectively (Table 
72). This information suggests that only some small portion of 
individuals in the stock are likely impacted (less than 22 percent), 
but that there is likely some level of repeat exposure of some subset 
of individuals that spend extended time within the SOCAL complex. 
Typically 2,424 percent would lead to the estimate of 48 days/year, 
however, given that a large number of gray whales are known to migrate 
through the SOCAL complex and the fact that there are only 4,678 total 
takes, we believe that it is more likely that a large number of 
individuals are taken one to a few times, while a small number staying 
in an area to feed for several days may be taken on 5-10

[[Page 67001]]

days. Regarding the severity of those individual takes by Level B 
behavioral harassment, we have explained that the duration of any 
exposure is expected to be between minutes and hours (i.e., relatively 
short) and the received sound levels largely below 172 dB with a 
portion up to 178 dB (i.e., of a moderate or lower level, less likely 
to evoke a severe response). Some of these takes could occur on a 
couple of sequential days for some small number of individuals, 
however, in these amounts it would still not be expected to adversely 
impact reproduction or survival of any individuals.
    Regarding the severity of TTS takes, we have explained that they 
are expected to be low-level, of short duration, and mostly not in a 
frequency band that would be expected to interfere with gray whale 
communication or other important low-frequency cues and that the 
associated lost opportunities and capabilities are not at a level that 
would impact reproduction or survival. For these same reasons (low 
level and frequency band), while a small permanent loss of hearing 
sensitivity may include some degree of energetic costs for compensating 
or may mean some small loss of opportunities or detection capabilities, 
at the expected scale the 7 estimated Level A harassment takes by PTS 
for gray whales would be unlikely to impact behaviors, opportunities, 
or detection capabilities to a degree that would interfere with 
reproductive success or survival of any individuals.
    Altogether, gray whales are not endangered or threatened under the 
ESA and the Eastern North Pacific stock is increasing. Only a small 
portion of the stock is impacted and any individual gray whale is 
likely to be disturbed at a low-moderate level, with likely many 
animals exposed only once or twice and a subset potentially disturbed 
across five to ten days. This low magnitude and severity of harassment 
effects is not expected to result in impacts to reproduction or 
survival for any individuals and nor are these harassment takes 
combined with the authorized mortality of two whales over the five year 
period expected to adversely affect this stock through impacts on 
annual rates of recruitment or survival. For these reasons, we have 
determined, in consideration of all of the effects of the Navy's 
activities combined, that the authorized take will have a negligible 
impact on the Eastern North Pacific stock of gray whales.
    Gray whale (Western North Pacific stock)--The Western North Pacific 
stock of gray whales is considered ``increasing,'' but is listed as 
endangered under the ESA. No mortality or Level A harassment is 
anticipated or authorized. This stock is expected and authorized to 
incur the very small number of 6 Level B harassment takes (2 behavioral 
and 4 TTS) to a stock with a SAR-estimated abundance of 140. These 
takes will likely accrue to different individuals, the behavioral 
disturbances will be of a low-moderate level, and the TTS instances 
will be at a low level and short duration. This low magnitude and 
severity of harassment effects is not expected to result in impacts on 
individual reproduction or survival, much less to adversely affect this 
stock through impacts on annual rates of recruitment or survival. For 
these reasons, we have determined, in consideration of all of the 
effects of the Navy's activities combined, that the authorized take 
will have a negligible impact on the Western North Pacific stock of 
gray whales.
    Humpback whale (Central North Pacific stock)--The SAR identifies 
this stock as ``increasing'' and the DPS is not listed under the ESA. 
No Level A harassment by tissue damage is authorized. NMFS will 
authorize two mortalities over the five years covered by this rule, or 
0.4 mortalities annually. The addition of this 0.4 annual mortality 
still leaves the total human-caused mortality well under the 
insignificance threshold for residual PBR.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), the number of estimated instances of take 
compared to the abundance, both throughout the HSTT Study Area and 
within the U.S. EEZ, respectively, is 180 and 161 percent (Table 71). 
This information and the complicated far-ranging nature of the stock 
structure suggests that some portion of the stock (but not all) are 
likely impacted, over one to several days per year, with little 
likelihood of take across sequential days. Regarding the severity of 
those individual takes by Level B behavioral harassment, we have 
explained that the duration of any exposure is expected to be between 
minutes and hours (i.e., relatively short) and the received sound 
levels largely below 172 dB with a portion up to 178 dB (i.e., of a 
moderate or lower level, less likely to evoke a severe response). 
Additionally, as noted above, there are two mitigation areas 
implemented by the Navy that span a large area of this important 
humpback reproductive area (BIA) and minimize impacts by limiting the 
use of MF1 active sonar and explosives, thereby reducing both the 
number and severity of takes of humpback whales. Regarding the severity 
of TTS takes, we have explained that they are expected to be low-level, 
of short duration, and mostly not in a frequency band that would be 
expected to interfere with humpback whale communication or other 
important low-frequency cues, and that the associated lost 
opportunities and capabilities are not at a level that would impact 
reproduction or survival. For these same reasons (low level and 
frequency band), while a small permanent loss of hearing sensitivity 
may include some degree of energetic costs for compensating or may mean 
some small loss of opportunities or detection capabilities, at the 
expected scale the 3 estimated Level A harassment takes by PTS for 
humpback whales would be unlikely to impact behaviors, opportunities, 
or detection capabilities to a degree that would interfere with 
reproductive success or survival of any individuals.
    Altogether, this stock is increasing and the DPS is not listed as 
endangered or threatened under the ESA. Only a small portion of the 
stock is impacted and any individual humpback whale is likely to be 
disturbed at a low-moderate level, with the taken individuals likely 
exposed between one and twelve days, with a few individuals potentially 
taken on a few sequential days. This low magnitude and severity of 
harassment effects is not expected to result in impacts on individual 
reproduction or survival, nor are these harassment takes combined with 
the authorized mortality expected to adversely affect this stock 
through effects on annual rates of recruitment or survival. For these 
reasons, we have determined, in consideration of all of the effects of 
the Navy's activities combined, that the authorized take will have a 
negligible impact on the Central North Pacific stock of humpback 
whales.
    Blue whale (Central North Pacific stock) and the Hawaii stocks of 
Bryde's whale, Fin whale, Minke whale, and Sei whale--The status of 
these stocks are not identified in the SARs. Blue whale (Central North 
Pacific stock) and the Hawaii stocks of fin whale and sei whale are 
listed as endangered under the ESA; the Hawaii stocks of minke whales 
and Bryde's whales are not listed under the ESA. No mortality or Level 
A harassment by tissue damage is anticipated or authorized for any of 
these stocks.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), the number of estimated instances of take 
compared to the abundance, both throughout the HSTT Study Area and 
within the U.S. EEZ, respectively, is 92-135 and 103-142

[[Page 67002]]

percent (Table 71). This information suggests that some portion of the 
stocks (but not all) are likely impacted, over one to several days per 
year, with little likelihood of take across sequential days. Regarding 
the severity of those individual takes by Level B behavioral 
harassment, we have explained that the duration of any exposure is 
expected to be between minutes and hours (i.e., relatively short) and 
the received sound levels largely below 172 dB with a portion up to 178 
dB (i.e., of a moderate or lower level, less likely to evoke a severe 
response). Regarding the severity of TTS takes, we have explained that 
they are expected to be low-level, of short duration, and mostly not in 
a frequency band that would be expected to interfere with mysticete 
communication or other important low-frequency cues--and that the 
associated lost opportunities and capabilities are not at a level that 
would impact reproduction or survival. For similar reasons (described 
above) the two estimated Level A harassment takes by PTS for the Hawaii 
stock of minke whales are unlikely to have any effects on the 
reproduction or survival of any individuals.
    Altogether, only a portion of these stocks are impacted and any 
individuals of these stocks are likely to be disturbed at a low-
moderate level, with the taken individuals likely exposed between one 
and several days, with little chance that any are taken across 
sequential days. This low magnitude and severity of harassment effects 
is not expected to result in impacts on individual reproduction or 
survival, much less impacts on annual rates of recruitment or survival. 
For these reasons, we have determined, in consideration of all of the 
effects of the Navy's activities combined, that the authorized take 
will have a negligible impact on these stocks.

Odontocetes

    This section builds on the broader discussion above and brings 
together the discussion of the different types and amounts of take that 
different stocks will incur, the applicable mitigation for each stock, 
and the status of the stocks to support the negligible impact 
determinations for each stock. We have previously described (above in 
this section and in the proposed rule, respectively, with no new 
applicable information received since publication of the proposed rule) 
the unlikelihood of any masking or habitat impacts having effects that 
would impact the reproduction or survival of any of the individual 
marine mammals affected by the Navy's activities. Here, we include 
information that applies to all of the odontocete species and stocks, 
which are then further divided and discussed in more detail in the 
following subsections: Sperm whales, dwarf sperm whales, and pygmy 
sperm whales; Dolphins and small whales; Beaked whales; and Dall's 
porpoise. These sub-sections include more specific information about 
the groups, as well as conclusions for each stock represented.
    The majority of takes by harassment of odontocetes in the HSTT 
Study Area are caused by sources from the MF1 active sonar bin (which 
includes hull-mounted sonar) because they are high level, typically 
narrowband sources at a frequency (in the 1-10 kHz range), which 
overlap a more sensitive portion (though not the most sensitive) of the 
MF hearing range, and they are used in a large portion of exercises 
(see Table 1.5-5 in the Navy's rulemaking/LOA application). For 
odontocetes other than beaked whales (for which these percentages are 
indicated separately in that section), most of the takes (98 percent) 
from the MF1 bin in the HSTT Study Area would result from received 
levels between 154 and 172 dB SPL. For the remaining active sonar bin 
types, the percentages are as follows: LF3 = 97 percent between 142 and 
160 dB SPL, LF5M = 99 percent between 106 and 118 dB SPL, MF4 = 99 
percent between 136 and 160 dB SPL, MF5 = 97 percent between 118 and 
148 dB SPL, and HF4 = 96 percent between 100 and 148 dB SPL. These 
values may be derived from the information in Tables 6.4-8 through 6.4-
12 in the Navy's rulemaking/LOA application (though they were provided 
directly to NMFS upon request). Based on this information, the majority 
of the takes by Level B behavioral harassment are expected to be low to 
sometimes moderate in nature, but still of a generally shorter 
duration.
    For all odontocetes, takes from explosives (Level B behavioral 
harassment, TTS, or PTS if present) comprise a very small fraction (and 
low number) of those caused by exposure to active sonar. Specifically, 
for all but six odontocete stocks the instances of PTS and TTS from 
explosives are five or fewer and 12 or fewer per stock, respectively. 
By virtue of the sheer density and abundance of these two stocks, long-
beaked and short-beaked dolphins incur a slightly higher number--13 or 
fewer and 30 or fewer instances of PTS and TTS, respectively. And, 
because of the lower threshold for HF species, pygmy and dwarf sperm 
whales have about 10-20 PTS takes and 30-100 TTS takes from explosives 
per stock, while Dall's porpoises have about 50 PTS takes and 300 PTS 
takes from explosives. Only five stocks incur take by harassment in the 
form of TTS or PTS from exposure to air guns and in all five cases it 
is limited to fewer than 10 takes each for TTS and PTS. No odontocetes 
incur PTS from exposure to pile driving, and only two stocks incur TTS 
in the amounts of one and three takes, respectively, from pile driving.
    Because the majority of harassment take of odontocetes results from 
the sources in the MF1 bin (typically a narrowband source in the 1-10 
kHz range), the vast majority of threshold shift caused by Navy sonar 
sources will typically occur across a narrower band in the range of 2-
20 kHz. This frequency range falls directly within the range of most 
odontocete vocalizations. However, odontocete vocalizations typically 
span a much wider range than this, and alternately, threshold shift 
from active sonar will often be in a narrower band (reflecting the 
narrower band source that caused it), which means that TTS incurred by 
odontocetes would typically only interfere with communication within a 
portion of their range (if it occurred during a time when communication 
with conspecifics was occurring) and as discussed earlier, it would 
only be expected to be of a short duration and relatively small degree. 
Odontocete echolocation occurs predominantly at frequencies 
significantly higher than 20 kHz, though there may be some small 
overlap at the lower part of their echolocating range for some species, 
which means that there is little likelihood that threshold shift, 
either temporary or permanent would interfere with feeding behaviors. 
Many of the other critical sounds that serve as cues for navigation and 
prey (e.g., waves, fish, invertebrates) occur below a few kHz, which 
means that detection of these signals will not be inhibited by most 
threshold shift either. The low number of takes by threshold shifts 
that might be incurred by individuals exposed to explosives, pile 
driving, or air guns would likely be lower frequency (5 kHz or less) 
and spanning a wider frequency range, which could slightly lower an 
individual's sensitivity to navigational or prey cues, or a small 
portion of communication calls, for several minutes to hours (if 
temporary) or permanently. There is no reason to think that any of the 
individual odontocetes taken by TTS would incur these types of takes 
over more than a few days of the year (with the exception of a few 
stocks, which are explicitly discussed below), at the most, and 
therefore they are unlikely to incur impacts on reproduction or 
survival.

[[Page 67003]]

PTS takes from these sources are very low, and while spanning a wider 
frequency band, are still expected to be of a low degree (i.e., low 
amount of hearing sensitivity loss).
    The range of potential behavioral effects of sound exposure on 
marine mammals generally, and odontocetes specifically, has been 
discussed in detail previously. There are behavioral patterns that 
differentiate the likely impacts on odontocetes as compared to 
mysticetes. First, odontocetes echolocate to find prey, which means 
that they actively send out sounds to detect their prey. While there 
are many strategies for hunting, one common pattern, especially for 
deeper diving species, is many repeated deep dives within a bout, and 
multiple bouts within a day, to find and catch prey. As discussed 
above, studies demonstrate that odontocetes cease their foraging dives 
in response to sound exposure. If enough foraging interruptions occur 
over multiple sequential days, and the individual either does not take 
in the necessary food, or must exert significant effort to find 
necessary food elsewhere, energy budget deficits can occur that could 
potentially result in impacts to reproductive success, such as 
increased cow/calf intervals (the time between successive calving). 
Second, many mysticetes rely on seasonal migratory patterns that 
position them in a geographic location at a specific time of the year 
to take advantage of ephemeral large abundances of prey (i.e., 
invertebrates or small fish, which they eat by the thousands), whereas 
odontocetes forage more homogeneously on one fish or squid at a time. 
Therefore, if odontocetes are interrupted while feeding, it is often 
possible to find more prey relatively nearby.
Sperm Whales, Dwarf Sperm Whales, and Pygmy Sperm Whales
    In this section, we bring together the discussion of marine mammals 
generally and odontocetes in particular regarding the different types 
and amounts of take that different stocks will incur, the applicable 
mitigation for each stock, and the status of the stocks to support the 
negligible impact determinations for each. We have also previously 
described the unlikelihood of any masking or habitat impacts to any 
marine mammals that would rise to the level of affecting individual 
fitness. The discussion in this section fairly narrowly focuses 
information that applies specifically to the sperm whale group, and 
then because there are multiple stock-specific factors in relation to 
differential Level B harassment effects and potential (and authorized) 
mortality, we break out specific findings into a few groups--CA/OR/WA 
stocks of sperm whales, dwarf sperm whales, and pygmy sperm whales; 
sperm whale (Hawaii stock); and Pygmy and dwarf sperm whales (Hawaii 
stocks).
    In Table 73 and Table 74 below, for sperm whales, dwarf sperm 
whales, and pygmy sperm whales, we indicate the total annual mortality, 
Level A and Level B harassment, and a number indicating the instances 
of total take as a percentage of abundance. No tissue damage is 
anticipated.
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    As discussed above, the majority of Level B harassment behavioral 
takes of odontocetes, and thereby sperm whales, is expected to be in 
the form of low to occasionally moderate severity of a generally 
shorter duration. As mentioned earlier in this section, we anticipate 
more severe effects from takes when animals are exposed to higher 
received levels or for longer durations. Occasional milder Level B 
behavioral harassment is unlikely to cause long-term consequences for 
individual animals or populations, even if some smaller subset of the 
takes are in the form of a longer (several hours or a day) and more 
moderate response. However, impacts across higher numbers of days, 
especially where sequential, have an increased probability of resulting 
in energetic deficits that could accrue to effects on reproductive 
success.
    We note here that dwarf and pygmy sperm whales, as HF-sensitive 
species, have a lower PTS threshold than all other groups and therefore 
are likely to experience larger amounts of TTS and PTS, and NMFS will 
accordingly authorize higher numbers. However, Kogia whales are still 
likely to avoid sound levels that would cause higher levels of TTS 
(greater than 20 dB) or PTS. Even though the number of TTS and PTS 
takes are relatively high, all of the reasons described above for why 
TTS and PTS are not expected to impact reproduction or survival still 
apply.
    We also note that impacts to dwarf sperm whale stocks will be 
reduced through the Hawaii Island Mitigation Area, which overlaps (but 
is larger than) the entirety of two BIAs for small resident populations 
of dwarf and pygmy sperm whales. In this mitigation area, the Navy will 
not conduct more than 300 hours of MF1 surface ship hull-mounted mid-
frequency active sonar or 20 hours of MF4 dipping sonar and will not 
use explosives during testing and training.
    Below we compile and summarize the information that supports our 
determination that the Navy's activities will not adversely impact 
recruitment or survival for any of the affected stocks addressed in 
this section.
    Sperm whale, dwarf sperm whale, and pygmy sperm whale (CA/OR/WA 
stocks)--The SAR identifies the CA/OR/WA stock of sperm whales as 
``stable'' and the species is listed as endangered under the ESA. The 
status of the CA/OR/WA stocks of pygmy and dwarf sperm whales is 
unknown and neither are listed under the ESA. Neither mortality nor 
Level A harassment by tissue damage from exposure to explosives is 
expected or authorized for any of these three stocks.
    Due to their pelagic distribution, small size, and cryptic 
behavior, pygmy sperm whales and dwarf sperm whales are rarely sighted 
during at-sea surveys and difficult to distinguish between when 
visually observed in the field. Many of the relatively few observations 
of Kogia spp. off the U.S. West Coast were not identified to species. 
All at-sea sightings of Kogia spp. have been identified as pygmy sperm 
whales or Kogia spp. Stranded dwarf sperm and pygmy sperm whales have 
been found on the U.S. West Coast, however dwarf sperm whale strandings 
are rare. NMFS SARs suggest that the majority of Kogia sighted off the 
U.S. West Coast were likely pygmy sperm whales. As such, the stock 
estimate in the NMFS SAR for pygmy sperm whales is the estimate derived 
for all Kogia spp. in the region (Barlow 2016), and no separate 
abundance estimate can be determined for dwarf sperm whales, though 
some low number likely reside in the U.S. EEZ. Due to the lack of 
abundance estimate it is not possible to predict the take of dwarf 
sperm whales and take estimates are identified as Kogia spp. (including 
both pygmy and dwarf sperm whales). We assume only a small portion of 
those takes are likely to be dwarf sperm whales as the density and 
abundance in the U.S. EEZ is thought to be low.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), the number of estimated total instances of take 
compared to the abundance (measured against both the Navy-estimated 
abundance and the SAR) is, respectively, 913 and 125 for sperm whales 
and 1,211 and 223 for Kogia spp., with a large proportion of these 
anticipated to be pygmy sperm whales due to the low abundance and 
density of dwarf sperm whales in the HSTT Study Area. (Table 74). Given 
the range of these stocks (which extends the entire length of the West 
Coast, as well as beyond the U.S. EEZ boundary), this information 
suggests that some portion of the individuals in these stocks will not 
be impacted, but that there is likely some repeat exposure (perhaps up 
to 24 days within a year for Kogia spp. and 18 days a year for sperm 
whales) of some small subset of individuals that spend extended time 
within the SOCAL Range. Additionally, while interrupted feeding bouts 
are a known response and concern for odontocetes, we also know that 
there are often viable alternative habitat options in the relative 
vicinity. Regarding the severity of those individual takes by Level B 
behavioral harassment, we have explained that the duration of any 
exposure is expected to be between minutes and hours (i.e., relatively 
short) and the received sound levels largely below 172 dB (i.e., of a

[[Page 67005]]

lower, to occasionally moderate, level and less likely to evoke a 
severe response). However, some of these takes could occur on a fair 
number of sequential days for some number on individuals.
    Regarding the severity of TTS takes, we have explained that they 
are expected to be low-level, of short duration, and mostly not in a 
frequency band that would be expected to interfere with sperm whale 
communication or other important low-frequency cues, and that the 
associated lost opportunities and capabilities are not at a level that 
would impact reproduction or survival. For these same reasons (low 
level and frequency band), while a small permanent loss of hearing 
sensitivity (PTS) may include some degree of energetic costs for 
compensating or may mean some small loss of opportunities or detection 
capabilities, at the expected scale the estimated Level A harassment 
takes by PTS for the dwarf and pygmy whale stocks would be unlikely to 
impact behaviors, opportunities, or detection capabilities to a degree 
that would interfere with reproductive success or survival of any 
individuals. Thus the 38 total Level A harassment takes by PTS for 
these two stocks would be unlikely to affect rates of recruitment and 
survival for the stocks.
    Altogether, most members of the stocks will likely be taken by 
Level B harassment (at a low to occasionally moderate level) over 
several days a year, and some smaller portion of the stocks are 
expected to be taken on a relatively moderate to high number of days 
(up to 18 or 24) across the year, some of which could be sequential 
days. Though the majority of impacts are expected to be of a lower to 
sometimes moderate severity, the larger number of takes for a subset of 
individuals makes it more likely that a small number of individuals 
could be interrupted during foraging in a manner and amount such that 
impacts to the energy budgets of females (from either losing feeding 
opportunities or expending considerable energy to find alternative 
feeding options) could cause them to forego reproduction for a year. 
Energetic impacts to males are generally meaningless to population 
rates unless they cause death, and it takes extreme energy deficits 
beyond what would ever be likely to result from these activities to 
cause the death of an adult marine mammal. As noted previously, 
however, foregone reproduction (especially for one year, which is the 
maximum predicted because the small number anticipated in any one year 
makes the probability that any individual would be impacted in this way 
twice in five years very low) has far less of an impact on population 
rates than mortality and a small number of instances of foregone 
reproduction would not be expected to adversely affect these stocks 
through effects on annual rates of recruitment or survival, and we note 
that residual PBR is 19 for pygmy dwarf sperm whales and 1.6 for sperm 
whales. Both the abundance and PBR are unknown for dwarf sperm whales, 
however, we know that take of this stock is likely significantly lower 
in magnitude and severity (i.e., lower number of total takes and 
repeated takes any individual) than pygmy sperm whales. For these 
reasons, in consideration of all of the effects of the Navy's 
activities combined, we have determined that the authorized take will 
have a negligible impact on the CA/OR/WA stocks of sperm whales and 
pygmy and dwarf sperm whales.
    Sperm whale (Hawaii stock)--The SAR does not identify a trend for 
this stock and the species is listed as endangered under the ESA. No 
Level A harassment by PTS or tissue damage is expected or authorized. 
NMFS will authorize one mortality over the 5 years covered by this 
rule, which is 0.2 mortalities annually. The addition of this 0.2 
annual mortality still leaves the total human-caused mortality well 
under the insignificance threshold for residual PBR.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), the number of estimated instances of take 
compared to the abundance, both throughout the HSTT Study Area and 
within the U.S. EEZ, respectively, is 151 and 147 percent (Table 73). 
This information and the sperm whale stock range suggest that likely 
only a smaller portion of the stock is impacted, over one to several 
days per year, with little likelihood of take across sequential days. 
Regarding the severity of those individual takes by Level B behavioral 
harassment, we have explained that the duration of any exposure is 
expected to be between minutes and hours (i.e., relatively short) and 
the received sound levels largely below 172 dB (i.e., of a lower, to 
occasionally moderate, level and less likely to evoke a severe 
response). Regarding the severity of TTS takes, we have explained that 
they are expected to be low-level, of short duration, and mostly not in 
a frequency band that would be expected to interfere with sperm whale 
communication or other important low-frequency cues, and that the 
associated lost opportunities and capabilities are not at a level that 
would impact reproduction or survival.
    Altogether, a relatively small portion of this stock is impacted 
and any individuals are likely to be disturbed at a low-moderate level, 
with the taken individuals likely exposed between one and several days, 
with little chance that any are taken across sequential days. This low 
magnitude and severity of harassment effects is not expected to result 
in impacts on individual reproduction or survival, nor are these 
harassment takes combined with the single authorized mortality expected 
to adversely affect the stock through annual rates of recruitment or 
survival. For these reasons, we have determined, in consideration of 
all of the effects of the Navy's activities combined, that the 
authorized take will have a negligible impact on the Hawaii stock of 
sperm whales.
    Pygmy and dwarf sperm whales (Hawaii stocks)--The SAR does not 
identify a trend for these stocks and the species are not listed under 
the ESA. No Level A harassment by tissue damage is authorized. 
Regarding the magnitude of Level B harassment takes (TTS and behavioral 
disruption), the number of estimated instances of take compared to the 
abundance, both throughout the HSTT Study Area and within the U.S. EEZ, 
respectively, is 244-249 and 235-240 percent (Table 73). This 
information and the pygmy and dwarf sperm whale stock ranges (at least 
throughout the U.S. EEZ around the entire Hawaiian Islands) suggest 
that likely a fair portion of each stock is not impacted, but that a 
subset of individuals may be over one to perhaps five days per year, 
with little likelihood of take across sequential days. Regarding the 
severity of those individual takes by Level B behavioral harassment, we 
have explained that the duration of any exposure is expected to be 
between minutes and hours (i.e., relatively short) and the received 
sound levels largely below 172 dB (i.e., of a lower, to occasionally 
moderate, level and less likely to evoke a severe response). 
Additionally, as noted earlier, within the Hawaii Island Mitigation 
Area, explosives are not used and the use of MF1 and MF4 active sonar 
is limited, greatly reducing the severity of impacts within the small 
resident population BIA for dwarf sperm whales, which is entirely 
contained within this mitigation area.
    Regarding the severity of TTS takes, we have explained that they 
are expected to be low-level, of short duration, and mostly not in a 
frequency band that would be expected to interfere with sperm whale 
communication or other important low-frequency cues--and that the 
associated lost opportunities and capabilities are not at a level that 
would impact reproduction or survival. For these same reasons (low

[[Page 67006]]

level and frequency band), while a small permanent loss of hearing 
sensitivity may include some degree of energetic costs for compensating 
or may mean some small loss of opportunities or detection capabilities, 
at the expected scale, estimated Level A harassment takes by PTS for 
dwarf and pygmy sperm whales would be unlikely to impact behaviors, 
opportunities, or detection capabilities to a degree that would 
interfere with reproductive success or survival of any individuals, 
even if it were to be experienced by an animal that also experiences 
one or more Level B harassment behavioral disruptions. Thus the 29 and 
64 total Level A harassment takes by PTS for dwarf and pygmy sperm 
whales, respectively, would be unlikely to affect rates of recruitment 
and survival for these stocks.
    Altogether, a portion of these stocks are likely to be impacted and 
any individuals are likely to be disturbed at a low-moderate level, 
with the taken individuals likely exposed between one and five days, 
with little chance that any are taken across sequential days. This low 
magnitude and severity of Level A and Level B harassment effects is not 
expected to result in impacts on individual reproduction or survival, 
much less impacts on annual rates of recruitment or survival. For these 
reasons, we have determined, in consideration of all of the effects of 
the Navy's activities combined, that the expected (and authorized) take 
will have a negligible impact on the Hawaii stocks of pygmy and dwarf 
sperm whales.
Beaked Whales
    In this section, we build on the broader odontocete discussion 
above (i.e., that information applies to beaked whales as well), except 
where we offer alternative information about the received levels for 
beaked whale Level B behavioral harassment. We bring together the 
discussion of the different types and amounts of take that different 
stocks will incur, the applicable mitigation for each stock, and the 
status of the stocks to support the negligible impact determinations 
for each stock. None of these species are listed as endangered or 
threatened under the ESA. For beaked whales, there is no predicted 
mortality or tissue damage for any stock. We have also described the 
unlikelihood of any masking or habitat impacts to any groups that would 
rise to the level of affecting individual fitness. The discussion below 
focuses on additional information that is specific to beaked whales (in 
addition to the general information on odontocetes provided above, 
which is relevant to these species) to support the conclusions for each 
stock. Because there are differential magnitudes of effect to the 
Hawaii stocks of beaked whales versus the CA/OR/WA stocks of beaked 
whales, we break out specific findings into those two groups.
    In Tables 75 and 76 below, for beaked whales, we indicate the total 
annual mortality, Level A and Level B harassment, and a number 
indicating the instances of total take as a percentage of abundance. No 
Level A harassment (PTS and Tissue Damage) takes are anticipated or 
authorized.
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    This first paragraph provides specific information that is in lieu 
of the parallel information provided for odontocetes as a whole. The 
majority of takes by harassment of beaked whales in the HSTT Study Area 
are caused by sources from the MF1 active sonar bin (which includes 
hull-mounted sonar) because they are high level narrowband sources in 
the 1-10 kHz range, which overlap a more sensitive portion (though not 
the most sensitive) of the MF hearing range, and of the sources 
expected to result in take, they are used in a large portion of 
exercises (see Table 1.5-5 in the Navy's rulemaking/LOA application). 
Most of the takes (94 percent) from the MF1 bin in the HSTT Study Area 
would result from received levels between 154 and 160 dB SPL. For the 
remaining active sonar bin types, the percentages are as follows: LF3 = 
90 percent between 136 and 148 dB SPL, LF5M = 99 percent between 100 
and 118 dB SPL, MF4 = 95 percent between 130 and 148 dB SPL, MF5 = 95 
percent between 100 and 142 dB SPL, and HF4 = 96 percent between 100 
and 148 dB SPL. These values may be derived from the information in 
Tables 6.4-8 through 6.4-12 in the Navy's rulemaking/LOA application 
(though they were provided directly to NMFS upon request). Given the 
levels they are exposed to and their sensitivity, some responses would 
be of a lower severity, but many would likely be considered moderate.
    As is the case with harbor porpoises, research has shown that 
beaked whales are especially sensitive to the presence of human 
activity (Pirotta et al., 2012; Tyack et al., 2011) and therefore have 
been assigned a lower harassment threshold, i.e., a more distant 
distance cutoff (50 km for high source level, 25 km for moderate source 
level).
    Beaked whales have been documented to exhibit avoidance of human 
activity or respond to vessel presence (Pirotta et al., 2012). Beaked 
whales were observed to react negatively to survey vessels or low 
altitude aircraft by quick diving and other avoidance maneuvers, and 
none were observed to approach vessels (Wursig et al., 1998). It has 
been speculated for some time that beaked whales might have unusual 
sensitivities to sonar sound due to their likelihood of stranding in 
conjunction with MFAS use, although few definitive causal relationships 
between MFAS use and strandings have been documented, and no such 
findings have been documented with Navy use in Hawaii and Southern 
California.
    Research and observations show that if beaked whales are exposed to 
sonar or other active acoustic sources, they may startle, break off 
feeding dives, and avoid the area of the sound source to levels of 157 
dB re 1 [micro]Pa, or below (McCarthy et al., 2011). Acoustic 
monitoring during actual sonar exercises revealed some beaked whales 
continuing to forage at levels up to 157 dB re 1 [micro]Pa (Tyack et 
al., 2011). Stimpert et al. (2014) tagged a Baird's beaked whale, which 
was subsequently exposed to simulated MFAS. Changes in the animal's 
dive behavior and locomotion were observed when received level reached 
127 dB re 1 [mu]Pa. However, Manzano-Roth et al. (2013) found that for 
beaked whale dives that continued to occur during MFAS activity, 
differences from normal dive profiles and click rates were not detected 
with estimated received levels up to 137 dB re 1 [micro]Pa while the 
animals were at depth during their dives. And in research done at the 
Navy's fixed tracking range in the Bahamas, animals were observed to 
leave the immediate area of the anti-submarine warfare training 
exercise (avoiding the sonar acoustic footprint at a distance where the 
received level was ``around 140 dB'' SPL, according to Tyack et al. 
(2011) but return within a few days after the event ended (Claridge and 
Durban, 2009; McCarthy et al., 2011; Moretti et al., 2009, 2010; Tyack 
et al., 2010, 2011). Tyack et al. (2011) report that, in reaction to 
sonar playbacks, most beaked whales stopped echolocating, made long 
slow ascent to the surface, and moved away from the sound. A similar 
behavioral response study conducted in Southern California waters 
during the 2010-2011 field season found that Cuvier's beaked whales 
exposed to MFAS displayed behavior ranging from initial orientation 
changes to avoidance responses characterized by energetic fluking and 
swimming away from the source (DeRuiter et al., 2013b). However, the 
authors did not detect similar responses to incidental exposure to 
distant naval sonar exercises at comparable received levels, indicating 
that context of the exposures (e.g., source proximity, controlled 
source ramp-up) may have been a significant factor. The study itself 
found the results inconclusive and meriting further investigation. 
Cuvier's beaked whale responses suggested particular sensitivity to 
sound exposure as consistent with results for Blainville's beaked 
whale.

[[Page 67008]]

    Populations of beaked whales and other odontocetes on the Bahamas 
and other Navy fixed ranges that have been operating for decades, 
appear to be stable. Behavioral reactions (avoidance of the area of 
Navy activity) seem likely in most cases if beaked whales are exposed 
to anti-submarine sonar within a few tens of kilometers, especially for 
prolonged periods (a few hours or more) since this is one of the most 
sensitive marine mammal groups to anthropogenic sound of any species or 
group studied to date and research indicates beaked whales will leave 
an area where anthropogenic sound is present (De Ruiter et al., 2013; 
Manzano-Roth et al., 2013; Moretti et al., 2014; Tyack et al., 2011). 
Research involving tagged Cuvier's beaked whales in the SOCAL Range 
Complex reported on by Falcone and Schorr (2012, 2014) indicates year-
round prolonged use of the Navy's training and testing area by these 
beaked whales and has documented movements in excess of hundreds of 
kilometers by some of those animals. Given that some of these animals 
may routinely move hundreds of kilometers as part of their normal 
pattern, leaving an area where sonar or other anthropogenic sound is 
present may have little, if any, cost to such an animal. Photo 
identification studies in the SOCAL Range Complex, a Navy range that is 
utilized for training and testing, have identified approximately 100 
individual Cuvier's beaked whale individuals with 40 percent having 
been seen in one or more prior years, with re-sightings up to seven 
years apart (Falcone and Schorr, 2014). These results indicate long-
term residency by individuals in an intensively used Navy training and 
testing area, which may also suggest a lack of long-term consequences 
as a result of exposure to Navy training and testing activities. Over 
eight years of passive acoustic monitoring on the Navy's instrumented 
range west of San Clemente Island documented no significant changes in 
annual and monthly beaked whale echolocation clicks, with the exception 
of repeated fall declines likely driven by a natural beaked whale life 
history functions (DiMarzio et al., 2018). Finally, results from 
passive acoustic monitoring estimated regional Cuvier's beaked whale 
densities were higher than indicated by the NMFS' broad scale visual 
surveys for the U.S. west coast (Hildebrand and McDonald, 2009).
    As mentioned earlier in the odontocete overview, we anticipate more 
severe effects from takes when animals are exposed to higher received 
levels or sequential days of impacts. Occasional instances of take by 
Level B behavioral harassment of a low to moderate severity are 
unlikely to affect reproduction or survival. Here, some small number of 
takes by Level B behavioral harassment could be in the form of a longer 
(several hours or a day) and more moderate response, and/or some small 
number could be repeated over more than several sequential days. 
Impacts to reproduction could be possible for some small number of 
individuals, but given the information presented regarding beaked whale 
movement patterns, their return to areas within hours to a few days 
after a disturbance, and their continued presence and abundance in the 
area of instrumented Navy ranges, these impacts seem somewhat less 
likely. Nonetheless, even where some smaller number of animals could 
experience effects on reproduction, those responses would not be 
expected to adversely affect rates of recruitment or survival.
    We also note that impacts to beaked whale stocks will be reduced 
through the Hawaii Island Mitigation Area, which overlaps (but is 
larger than) almost the entirety of two BIAs for small resident 
populations of Blainville's and Cuvier's beaked whales (the mitigation 
area covers all of the BIA for Blainville's and all but a very small 
portion of the BIA for Cuvier's). In this mitigation area, the Navy 
will not conduct more than 300 hours of MF1 surface ship hull-mounted 
mid-frequency active sonar and not more than 20 hours of MF4 dipping 
sonar and will not use explosives during testing and training.
    Below we synthesize and summarize the information that supports our 
determination that the Navy's activities will not adversely impact 
recruitment or survival rates for any of the affected stocks addressed 
in this section:
    Blainville's, Cuvier's, and Longman's beaked whales (Hawaii 
stocks)--The SAR does not identify a trend for these stocks and the 
species are not listed under the ESA. No mortality or Level A 
harassment are expected or authorized for any of these three stocks. 
Regarding the magnitude of Level B harassment takes (TTS and behavioral 
disruption), the number of estimated instances of take compared to the 
abundance, both throughout the HSTT Study Area and within the U.S. EEZ, 
respectively, is 521-545 and 514-539 percent (Table 75). This 
information and the stock ranges (at least of the small, resident 
Island associated stocks around Hawaii) suggest that likely a fair 
portion of the stocks (but not all) will be impacted, over one to 
perhaps eleven days per year, with little likelihood of much take 
across sequential days. Regarding the severity of those individual 
takes by Level B behavioral harassment, we have explained that the 
duration of any exposure is expected to be between minutes and hours 
(i.e., relatively short) and the received sound levels largely below 
160 dB, though with beaked whales, which are considered somewhat more 
sensitive, this could mean that some individuals will leave preferred 
habitat for a day or two (i.e., moderate level takes). However, while 
interrupted feeding bouts are a known response and concern for 
odontocetes, we also know that there are often viable alternative 
habitat options nearby. Additionally, as noted earlier, within the 
Hawaii Island mitigation area (which entirely contains the BIAs for 
Cuvier's and Blainville's beaked whales), explosives are not used and 
the use of MF1 and MF4 active sonar is limited, greatly reducing the 
severity of impacts within these two small resident populations.
    Regarding the severity of TTS takes, we have explained that they 
are expected to be low-level, of short duration, and mostly not in a 
frequency band that would be expected to interfere with beaked whale 
communication or other important low-frequency cues, and that the 
associated lost opportunities and capabilities are not at a level that 
would impact reproduction or survival.
    Altogether, a fair portion of these stocks are impacted and any 
individuals are likely to be disturbed at a moderate level, with the 
taken individuals likely exposed between one and eleven days, with 
little chance that individuals are taken across more than a few 
sequential days. This low, to occasionally moderate, magnitude and 
severity of harassment effects is not expected to result in impacts on 
individual reproduction or survival, much less impacts on annual rates 
of recruitment or survival. For these reasons, we have determined, in 
consideration of all of the effects of the Navy's activities combined, 
that the authorized take will have a negligible impact on the Hawaii 
stocks of beaked whales.
    Baird's and Cuvier's beaked whales and Mesoplodon species (all CA/
OR/WA stocks)--The species are not listed under the ESA and their 
populations have been identified as ``stable,'' ``decreasing,'' and 
``increasing,'' respectively. No mortality or Level A harassment are 
expected or authorized for any of these three stocks.
    No methods are available to distinguish between the six species of 
Mesoplodon beaked whale CA/OR/WA stocks (Blainville's beaked whale (M. 
densirostris), Perrin's beaked whale (M. perrini), Lesser beaked whale 
(M.

[[Page 67009]]

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). Bycatch 
and stranding records from the region indicate that the Hubb's beaked 
whale is most commonly encountered (Carretta et al., 2008, Moore and 
Barlow, 2013). As indicated in the SAR, no species-specific abundance 
estimates are available, the abundance estimate includes all CA/OR/WA 
Mesoplodon spp, and the six species are managed as one unit. Due to the 
lack of species-specific abundance estimates it is not possible to 
predict the take of individual species and take estimates are 
identified as Mesoplodon spp.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), the number of estimated total instances of take 
compared to the abundance for these stocks is 2762, 2212, and 6960 
percent (measured against Navy-estimated abundance) and 76, 351, and 
203 percent (measured against the SAR) for Baird's beaked whales, 
Cuvier's beaked whales, and Mesoplodon spp., respectively (Table 76). 
Given the ranges of these stocks, this information suggests that some 
smaller portion of the individuals of these stocks will be taken, and 
that some subset of individuals within the stock will be taken 
repeatedly within the year (perhaps up to 20-25 days)--potentially over 
a fair number of sequential days, especially where individuals spend 
extensive time in the SOCAL Range (note that we predicted lower days of 
repeated exposure for these stocks than their percentages might have 
suggested because of the lower overall number of takes). While 
interrupted feeding bouts are a known response and concern for 
odontocetes, we also know that there are often viable alternative 
habitat options in the relative vicinity. Regarding the severity of 
those individual takes by Level B behavioral harassment, we have 
explained that the duration of any exposure is expected to be between 
minutes and hours (i.e., relatively short) and the received sound 
levels largely below 160 dB, though with beaked whales, which are 
considered somewhat more sensitive, this could mean that some 
individuals will leave preferred habitat for a day or two (i.e., of a 
moderate level). However, as noted, some of these takes could occur on 
a fair number of sequential days for these stocks.
    As described previously, the severity of TTS takes, is expected to 
be low-level, of short duration, and mostly not in a frequency band 
that would be expected to interfere significantly with conspecific 
communication, echolocation, or other important low-frequency cues. 
Therefore, the associated lost opportunities and capabilities would not 
be expected to impact reproduction or survival. For similar reasons 
(described above) the single estimated Level A harassment take by PTS 
for this stock is unlikely to have any effects on the reproduction or 
survival of any individuals.
    Altogether, a portion of these stocks will likely be taken (at a 
moderate or sometimes low level) over several days a year, and some 
smaller portion of the stock is expected to be taken on a relatively 
moderate to high number of days across the year, some of which could be 
sequential days. Though the majority of impacts are expected to be of a 
moderate severity, the repeated takes over a potentially fair number of 
sequential days for some individuals makes it more likely that a small 
number of individuals could be interrupted during foraging in a manner 
and amount such that impacts to the energy budgets of females (from 
either losing feeding opportunities or expending considerable energy to 
find alternative feeding options) could cause them to forego 
reproduction for a year. Energetic impacts to males are generally 
meaningless to population rates unless they cause death, and it takes 
extreme energy deficits beyond what would ever be likely to result from 
these activities to cause the death of an adult marine mammal). As 
noted previously, however, foregone reproduction (especially for only 
one year in five, as discussed previously) has far less of an impact on 
population rates than mortality and a small number of instances of 
foregone reproduction would not be expected to adversely affect these 
stocks through effects on annual rates of recruitment or survival, 
especially given the residual PBR of these three beaked whale stocks 
(16, 21, and 20, respectively).
    Further, Navy activities have been conducted in SOCAL for many 
years at similar levels and the SAR considers Mesoplodon spp. as 
increasing and Baird's beaked whales as stable. While NMFS' SAR 
indicates that Cuvier's beaked whales on the U.S. West Coast are 
declining based on a Bayesian trend analysis of NMFS' survey data 
collected from 1991 through 2014, results from passive acoustic 
monitoring and other research have estimated regional Cuvier's beaked 
whale densities that were higher than indicated by NMFS' broad-scale 
visual surveys for the U.S. West Coast (Debich et al., 2015a; Debich et 
al., 2015b; Falcone and Schorr, 2012, 2014; Hildebrand et al., 2009; 
Moretti, 2016; [Scaron]irovi[cacute] et al., 2016; Smultea and 
Jefferson, 2014). Research also indicates higher than expected 
residency in the Navy's instrumented Southern California Anti-Submarine 
Warfare Range in particular (Falcone and Schorr, 2012) and photo 
identification studies in the SOCAL have identified approximately 100 
individual Cuvier's beaked whale individuals with 40 percent having 
been seen in one or more prior years, with re-sightings up to 7 years 
apart (Falcone and Schorr, 2014). The documented residency by many 
Cuvier's beaked whales over multiple years suggest that a stable 
population may exist in that small portion of the stock's overall range 
(Falcone et al., 2009; Falcone and Schorr, 2014; Schorr et al., 2017).
    For these reasons, in consideration of all of the effects of the 
Navy's activities combined, we have determined that the authorized take 
will have a negligible impact on the CA/OR/WA stocks of Baird's and 
Cuvier's beaked whales, as well as all six species included within the 
Mesoplodon spp.
Small Whales and Dolphins
    This section builds on the broader discussion above and compiles 
the discussion of the different types and amounts of take that 
different stocks will incur, the applicable mitigation for each stock, 
and the status of the stocks to support the negligible impact 
determinations for each stock. None of these species are listed as 
endangered or threatened under the ESA. We also have described the 
unlikelihood of any masking or habitat impacts to any groups that would 
rise to the level of affecting individual fitness. The discussion below 
focuses on additional information that is specific to the dolphin taxa 
(in addition to the general information on odontocetes provided above, 
which is relevant to these species) and to support the summarized 
group-specific conclusions in the subsequent sections. Because of 
several factors, we break out specific findings into three groups: 1) 
long-beaked common dolphin (California stock), Northern right whale 
dolphin, and short-beaked common dolphin (CA/OR/WA stocks), which all 
have authorized mortality or tissue damage; 2) all other SOCAL dolphin 
stocks except those identified in 1; and 3) all HRC dolphin stocks.
    In Tables 77 and 78 below, for odontocetes (in this section 
odontocetes refers specifically to the small whales and dolphins 
indicated in Tables 77 and 78), we indicate the total annual

[[Page 67010]]

mortality, Level A and Level B harassment, and a number indicating the 
instances of total take as a percentage of abundance.
BILLING CODE 3510-22-P
[GRAPHIC] [TIFF OMITTED] TR27DE18.036


[[Page 67011]]


[GRAPHIC] [TIFF OMITTED] TR27DE18.037

BILLING CODE 3510-22-C
    As described above, the large majority of Level B behavioral 
harassments to odontocetes, and thereby dolphins and small whales, from 
hull-mounted sonar (MF1) in the HSTT Study Area would result from 
received levels between 160 and 172 dB SPL. Therefore, the majority of 
Level B harassment takes are expected to be in the form of low to 
occasionally moderate responses of a generally shorter duration. As 
mentioned earlier in this section, we anticipate more severe effects 
from takes when animals are exposed to higher received levels. 
Occasional milder occurrences of Level B behavioral harassment are 
unlikely to cause long-term consequences for individual animals or 
populations that have any effect on reproduction or survival. Some 
behavioral responses could be in the form of a longer (several hours or 
a day) and more moderate response, but because they are not expected to 
be repeated over more than several sequential days at the most, impacts 
to reproduction or survival for most animals are not anticipated. Even 
where a few animals could experience effects on reproduction, for the 
reasons explained below this would not affect rates of recruitment or 
survival.
    Research and observations show that if delphinids are exposed to 
sonar or other active acoustic sources they may react in a number of 
ways depending on their experience with the sound source and what 
activity they are engaged in at the time of the acoustic exposure. 
Delphinids may not react at all until the sound source is approaching 
within a few hundred meters to within a few kilometers depending on the 
environmental conditions and species. Some dolphin species (the more 
surface-dwelling taxa--typically those with ``dolphin'' in the common 
name, such as bottlenose dolphins, spotted dolphins, common dolphins, 
spinner dolphins, rough-toothed dolphins, etc., but not Risso's 
dolphin), especially those residing in more industrialized or busy 
areas, have demonstrated more tolerance for disturbance and loud sounds 
and many of these species are known to approach vessels to bow-ride. 
These species are often considered generally less sensitive to 
disturbance. Deep-diving dolphins that reside in deeper waters and 
generally have fewer interactions with human activities are more likely 
to demonstrate more typical avoidance reactions and foraging 
interruptions as described above in the odontocete overview.
    Identified important areas for odontocetes (BIAs for small resident 
populations) will be protected by the Navy's mitigation areas. The size 
of the 4-Islands Region Mitigation Area has been expanded to include an 
area north of Maui and Molokai and overlaps an area identified as a BIA 
for the endangered Main Hawaiian Islands insular false killer whale 
(Baird et al., 2015; Van Parijs, 2015) (see Figure 5.4-3, in Chapter 5 
Mitigation Areas for Marine Mammals in the Hawaii Range Complex of the 
HSTT FEIS/OEIS). The 4-Islands Region Mitigation Area provides partial 
protection for identified biologically important areas that span 
multiple islands for four species (small and resident populations) 
including false killer whales, common bottlenose dolphin, pantropical 
spotted dolphin, and spinner dolphin, by not using mid-frequency active 
anti-submarine warfare sensor MF1 in the area during testing or 
training.
    The Navy's Hawaii Island Mitigation Area also provides additional 
protection for identified biologically important areas (small and 
resident populations) for multiple Main Hawaii Island species by not 
conducting more than 300 hours of MF1 surface ship hull-mounted mid-
frequency active sonar or 20 hours of MF4 dipping sonar and not using 
explosives during testing and training. Specifically, this Mitigation 
Area entirely encompasses the BIAs for insular pygmy killer whales, 
melon-headed whales, short-finned pilot whales, and the Hawaii 
population of pantropical spotted dolphins; encompasses a large portion 
of the rough-toothed dolphin BIA; and overlaps the Hawaii Island 
portion of the multi-Island BIAs for false killer whales, common 
bottlenose dolphin, and spinner dolphin.
    Below we synthesize and summarize the information that supports our

[[Page 67012]]

determination that the Navy's activities will not adversely impact 
recruitment or survival for any of the affected stocks addressed in 
this section:
    Long-beaked common dolphin (California stock), northern right whale 
dolphin (CA/OR/WA stock), and short-beaked common dolphin (CA/OR/WA 
stock)--None of these stocks is listed under the ESA and their stock 
statuses are considered ``increasing,'' ``unknown,'' and ``stable,'' 
respectively. Short-beaked common dolphins are authorized for six takes 
by mortality over the five-year rule, or 1.2 M/SI annually. The 
addition of this 1.2 annual mortality still leaves the total human-
caused mortality well under the insignificance threshold for residual 
PBR. The three stocks are expected and authorized to accrue 2, 1, and 
10 Level A harassment takes from tissue damage resulting from exposure 
to explosives, respectively. As described in greater detail previously, 
the impacts of a Level A harassment take by tissue damage could range 
in impact from minor to something just less than M/SI that could 
seriously impact fitness. However, given the Navy's procedural 
mitigation, exposure at the closer to the source and more severe end of 
the spectrum is less likely and we cautiously assume some moderate 
impact for these takes that could lower the affected individual's 
fitness within the year such that a female (assuming a 50 percent 
chance of it being a female) might forego reproduction for one year. As 
noted previously, foregone reproduction has less of an impact on 
population rates than death (especially for only one year in five), and 
1 to 10 instances would not be expected to impact annual rates of 
recruitment or survival for these stocks.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), the number of estimated total instances of take 
compared to the abundance (measured against both the Navy-estimated 
abundance and the SAR) is 2411, 1273, and 571 (respective to the stocks 
listed in the heading) and 244, 369, and 229 (respective to the stocks 
listed in the heading) percent (Table 78). Given the range of these 
stocks, this information suggests that likely some portion (but not all 
or even the majority) of the individuals in the Northern right whale 
dolphin and short-beaked common dolphin stocks are likely impacted, 
while it is entirely possible that most or all of the range-limited 
long-beaked common dolphin is taken. All three stocks likely will 
experience some repeat Level B harassment exposure (perhaps up to 48, 
25, or 11 days within a year, respective to the stocks listed in the 
heading) of some subset of individuals that spend extended time within 
the SOCAL range complex. While interrupted feeding bouts are a known 
response and concern for odontocetes, we also know that there are often 
viable alternative habitat options in the relative vicinity. Regarding 
the severity of those individual takes by Level B behavioral 
harassment, we have explained that the duration of any exposure is 
expected to be between minutes and hours (i.e., relatively short) and 
the received sound levels largely below 172 dB with a portion up to 178 
dB (i.e., of a moderate or lower level, less likely to evoke a severe 
response). However, some of these takes could occur on a fair number of 
sequential days for long-beaked common dolphins or northern right whale 
dolphins, or even some number of short-beaked common dolphins, given 
the high number of total takes (i.e., the probability that some number 
of individuals get taken on a higher number of sequential days is 
higher, because the total take number is relatively high, even though 
percentage not that high).
    As described previously, the severity of TTS takes, is expected to 
be low-level, of short duration, and mostly not in a frequency band 
that would be expected to interfere significantly with conspecific 
communication, echolocation, or other important low-frequency cues, and 
the associated lost opportunities and capabilities would not be 
expected to impact reproduction or survival. For these same reasons 
(low level and frequency band), while a small permanent loss of hearing 
sensitivity may include some degree of energetic costs for compensating 
or may mean some small loss of opportunities or detection capabilities, 
as discussed above, it would be unlikely to impact behaviors, 
opportunities, or detection capabilities to a degree that would 
interfere with reproductive success or survival of any individuals.
    Altogether and as described in more detail immediately above, 
short-beaked common dolphins are authorized for 1.2 annual lethal 
takes, all three stocks may experience a very small number of takes by 
tissue damage or PTS (relative to the stock abundance and PBR), and a 
moderate to large portion of all three stocks will likely be taken (at 
a low to occasionally moderate level) over several days a year, and 
some smaller portion of these stocks is expected to be taken on a 
relatively moderate to high number of days across the year, some of 
which could be sequential days. Though the majority of impacts are 
expected to be of a lower to sometimes moderate severity, the larger 
number of takes (in total and for certain individuals) makes it more 
likely (probabilistically) that a small number of individuals could be 
interrupted during foraging in a manner and amount such that impacts to 
the energy budgets of females (from either losing feeding opportunities 
or expending considerable energy to find alternative feeding options) 
could cause them to forego reproduction for a year. Energetic impacts 
to males are generally meaningless to population rates unless they 
cause death, and it takes extreme energy deficits beyond what would 
ever be likely to result from these activities to cause the death of an 
adult marine mammal. As noted previously, however, foregone 
reproduction (especially for only one year out of five) has far less of 
an impact on population rates than mortality and a small number of 
instances of foregone reproduction (including in combination with that 
which might result from the small number of tissue damage takes) would 
not be expected to adversely affect the stocks through effects on 
annual rates of recruitment or survival, especially given the very high 
residual PBRs of these stocks (621, 175, and 8353, respectively). For 
these reasons, in consideration of all of the effects of the Navy's 
activities combined (mortality, Level A harassment, and Level B 
harassment), we have determined that the authorized take will have a 
negligible impact on these three stocks of dolphins.
    All other SOCAL dolphin stocks (except Long-beaked common dolphin, 
Northern right whale dolphin, and short-beaked common dolphin)--None of 
these stocks is listed under the ESA and their stock statuses are 
considered ``unknown,'' except for the bottlenose dolphin (California 
coastal stock) and killer whale (Eastern North Pacific stock), which 
are considered ``stable.'' No M/SI or Level A harassment via tissue 
damage from exposure to explosives is expected or authorized for these 
stocks.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), the number of estimated total instances of take 
compared to the abundance (measured against both the Navy-estimated 
abundance and the SAR) is from 440-2675 and 45 to 2881, respectively 
(Table 78). Given the range of these stocks (along the entire U.S. West 
Coast, or even beyond, with some also extending seaward of the HSTT 
Study Area boundaries), this information suggests that some portion 
(but not all or even the majority) of the individuals of any of these 
stocks will be taken, with the exception that most or all of the 
individuals of the more

[[Page 67013]]

range-limited California coastal stock of bottlenose dolphin may be 
taken. It is also likely that some subset of individuals within most of 
these stocks will be taken repeatedly within the year (perhaps up to 
10-15 days within a year), but with no more than several potentially 
sequential days, although the CA/OR/WA stocks of bottlenose dolphins, 
Pacific white-sided dolphins, and Risso's dolphins may include 
individuals that are taken repeatedly within the year over a higher 
number of days (up to 57, 22, and 40 days, respectively) and 
potentially over a fair number of sequential days, especially where 
individuals spend extensive time in the SOCAL range complex. Note that 
though percentages are high for the Eastern North Pacific stock of 
killer whales and short-finned pilot whales, given the low overall 
number of takes, it is highly unlikely that any individuals would be 
taken across the number of days their percentages would suggest. While 
interrupted feeding bouts are a known response and concern for 
odontocetes, we also know that there are often viable alternative 
habitat options in the relative vicinity. Regarding the severity of 
those individual takes by Level B behavioral harassment, we have 
explained that the duration of any exposure is expected to be between 
minutes and hours (i.e., relatively short) and the received sound 
levels largely below 172 dB (i.e., of a lower, or sometimes moderate 
level, less likely to evoke a severe response). However, as noted, some 
of these takes could occur on a fair number of sequential days for the 
three stocks listed earlier.
    As described previously, regarding the severity of TTS takes, is 
expected to be low-level, of short duration, and mostly not in a 
frequency band that would be expected to interfere significantly with 
conspecific communication, echolocation, or other important low-
frequency cues. For these same reasons (low level and frequency band), 
while a small permanent loss of hearing sensitivity may include some 
degree of energetic costs for compensating or may mean some small loss 
of opportunities or detection capabilities, it would be unlikely to 
impact behaviors, opportunities, or detection capabilities to a degree 
that would interfere with reproductive success or survival of any 
individuals.
    Altogether, a portion of all of these stocks will likely be taken 
(at a low to occasionally moderate level) over several days a year, and 
some smaller portion of CA/OR/WA stocks of bottlenose dolphins, Pacific 
white-sided dolphins, and Risso's dolphins, specifically, are expected 
to be taken on a relatively moderate to high number of days across the 
year, some of which could be sequential days. Though the majority of 
impacts are expected to be of a lower to sometimes moderate severity, 
the larger number of takes (in total and for certain individuals) for 
the CA/OR/WA stocks of bottlenose dolphins, Pacific white-sided 
dolphins, and Risso's dolphins makes it more likely (probabilistically) 
that a small number of individuals could be interrupted during foraging 
in a manner and amount such that impacts to the energy budgets of 
females (from either losing feeding opportunities or expending 
considerable energy to find alternative feeding options) could cause 
them to forego reproduction for a year. Energetic impacts to males are 
generally meaningless to population rates unless they cause death, and 
it takes extreme energy deficits beyond what would ever be likely to 
result from these activities to cause the death of an adult marine 
mammal. As noted previously, however, foregone reproduction (especially 
for only one year in five) has far less of an impact on population 
rates than mortality and a small number of instances of foregone 
reproduction would not be expected to adversely affect the stocks 
through effects on annual rates of recruitment or survival, especially 
given the residual PBRs of the CA/OR/WA stocks of bottlenose dolphins, 
Pacific white-sided dolphins, and Risso's dolphins (9.4, 183, and 84, 
respectively). For these reasons, in consideration of all of the 
effects of the Navy's activities combined, we have determined that the 
authorized take will have a negligible impact on these stocks of 
dolphins.
    All HRC dolphin stocks--With the exception of the Main Hawaiian 
Island stock of false killer whales (listed as endangered under the 
ESA, with the MMPA stock identified as ``decreasing''), none of these 
stocks are listed under the ESA and their stock statuses are considered 
``unknown.'' No M/SI or Level A harassment via tissue damage from 
exposure to explosives is expected or authorized for these stocks.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), the number of estimated total instances of take 
compared to the abundance (measured against both the Navy-estimated 
abundance and the SAR) is from 46-1169 percent and 41 to 2130 percent, 
respectively (Table 77). Given the ranges of these stocks (many of them 
are small, resident, island-associated stocks), this information 
suggests that a fairly large portion of the individuals of many of 
these stocks will be taken, but that most individuals will only be 
impacted across a smaller to moderate number of days within the year 
(1-15), and with no more than several potentially sequential days, 
although two stocks (the Oahu stocks of bottlenose dolphin and 
pantropical spotted dolphin) have a slightly higher percentage, 
suggesting they could be taken up to 23 days within a year, with 
perhaps a few more of those days being sequential. We note that 
although the percentage is higher for the tropical stock of pygmy 
killer whale within the U.S. EEZ (2130), given (1) the low overall 
number of takes (760) and (2) the fact that the small within-U.S. EEZ 
abundance is not a static set of individuals, but rather individuals 
moving in and out of the U.S. EEZ making it more appropriate to use the 
percentage comparison for the total takes versus total abundance--it is 
highly unlikely that any individuals would be taken across the number 
of days the within-U.S. EEZ percentage suggests (42). While interrupted 
feeding bouts are a known response and concern for odontocetes, we also 
know that there are often viable alternative habitat options in the 
relative vicinity. Regarding the severity of those individual takes by 
Level B behavioral harassment, we have explained that the duration of 
any exposure is expected to be between minutes and hours (i.e., 
relatively short) and the received sound levels largely below 172 dB 
(i.e., of a lower, or sometimes moderate level, less likely to evoke a 
severe response). However, as noted, some of these takes could occur on 
a fair number of sequential days for the Oahu stocks of bottlenose 
dolphin and pantropical spotted dolphins.
    Regarding the severity of TTS takes, as described previously they 
are expected to be low-level, of short duration, and mostly not in a 
frequency band that would be expected to interfere significantly with 
conspecific communication, echolocation, or other important low-
frequency cues. For these same reasons (low level and frequency band), 
while a small permanent loss of hearing sensitivity may include some 
degree of energetic costs for compensating or may mean some small loss 
of opportunities or detection capabilities, they would be unlikely to 
impact behaviors, opportunities, or detection capabilities to a degree 
that would interfere with reproductive success or survival of any 
individuals, even if accrued to individuals that are also taken by 
behavioral harassment at the same time.
    Altogether, most of these stocks (all but the Oahu stocks of 
bottlenose dolphin and pantropical spotted

[[Page 67014]]

dolphins) will likely be taken (at a low to occasionally moderate 
level) over several days a year, with some smaller portion of the stock 
potentially taken on a more moderate number of days across the year 
(perhaps up to 15 days for Fraser's dolphin, though others notably 
less), some of which could be across a few sequential days, which is 
not expected to affect the reproductive success or survival of 
individuals. For the Oahu stocks of bottlenose dolphin and pantropical 
spotted dolphins, some subset of individuals could be taken up to 23 
days in a year, with some small number being taken across several 
sequential days, such that a small number of individuals could be 
interrupted during foraging in a manner and amount such that impacts to 
the energy budgets of females (from either losing feeding opportunities 
or expending considerable energy to find alternative feeding options) 
could cause them to forego reproduction for a year. Energetic impacts 
to males are generally meaningless to population rates unless they 
cause death, and it takes extreme energy deficits beyond what would 
ever be likely to result from these activities to cause the death of an 
adult marine mammal. As noted previously, however, foregone 
reproduction (especially for one year, which is the maximum predicted 
because the small number anticipated in any one year makes the 
probability that any individual would be impacted in this way twice in 
five years very low) has far less of an impact on population rates than 
mortality and a small number of instances of foregone reproduction 
would not be expected to adversely affect these two stocks through 
effects on annual rates of recruitment or survival.
    For these reasons, in consideration of all of the effects of the 
Navy's activities combined, we have determined that the authorized take 
will have a negligible impact on all of the stocks of dolphins found in 
the vicinity of the HRC (Table 77).
Dall's Porpoise
    In this section, we build on the broader odontocete discussion 
above (i.e., that information applies to Dall's porpoises as well), 
except where we offer alternative information about the received levels 
for Dall's porpoise Level B behavioral harassment. We discuss the 
different types and amounts of take that the stock will incur, the 
applicable mitigation for the stock, and the status of the stock to 
support the negligible impact determination. The discussion below 
focuses on additional information that is specific to porpoises (in 
addition to the general information on odontocetes provided above, 
which is relevant to this species) to support the conclusion for this 
stock. We have described previously (above in this section and in the 
proposed rule, respectively, with no new applicable information 
received since publication of the proposed rule) the unlikelihood of 
any masking or habitat impacts to Dall's porpoises that would affect 
reproduction or survival.
    In Table 79 below, for Dall's porpoise, we indicate the total 
annual mortality, Level A and Level B harassment, and a number 
indicating the instances of total take as a percentage of abundance.
[GRAPHIC] [TIFF OMITTED] TR27DE18.038

    Most Level B harassments to Dall's porpoise from hull-mounted sonar 
(MF1) in the HSTT Study Area would result from received levels between 
154 and 166 dB SPL (85 percent). While harbor porpoises have been 
observed to be especially sensitive to human activity, the same types 
of responses have not been observed in Dall's porpoises. Dall's 
porpoises are typically notably longer than, and weigh more than twice 
as much as, harbor porpoises, making them generally less likely to be 
preyed upon and likely differentiating their behavioral repertoire 
somewhat from harbor porpoises. Further, they are typically seen in 
large groups and feeding aggregations, or exhibiting bow-riding 
behaviors, which is very different from the group dynamics observed in 
the more typically solitary, cryptic harbor porpoises, which are not 
often seen bow-riding. For these reasons, Dall's porpoises are not 
treated as especially sensitive species (versus harbor porpoises which 
have a lower behavioral harassment threshold and more distant cutoff) 
but, rather, are analyzed similarly to other odontocetes. Therefore, 
the majority of Level B takes are expected to be in the form of milder 
responses compared to higher level exposures. As mentioned earlier in 
this section, we anticipate more severe effects from takes when animals 
are exposed to higher received levels.
    Dall's porpoise is not listed under the ESA and the stock status is 
considered ``unknown.'' No M/SI or Level A harassment via tissue damage 
from exposure to explosives is expected or authorized for this stock.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), the number of estimated total instances of take 
compared to the abundance (measured against both the Navy-estimated 
abundance and the SAR) is 2170 and 173, respectively (Table 79). Given 
the range of this stock (up the U.S. West Coast through Washington and 
sometimes beyond the U.S. EEZ), this information suggests that some 
smaller portion of the individuals of these stocks will be taken, and 
that

[[Page 67015]]

some subset of individuals within the stock will be taken repeatedly 
within the year (perhaps up to 42 days)--potentially over a fair number 
of sequential days, especially where individuals spend extensive time 
in the SOCAL range complex. While interrupted feeding bouts are a known 
response and concern for odontocetes, we also know that there are often 
viable alternative habitat options in the relative vicinity. Regarding 
the severity of those individual takes by Level B behavioral 
harassment, we have explained that the duration of any exposure is 
expected to be between minutes and hours (i.e., relatively short) and 
the received sound levels largely below 172 dB (i.e., of a lower, or 
sometimes moderate level, less likely to evoke a severe response). 
However, as noted, some of these takes could occur on a fair number of 
sequential days for this stock.
    As described previously, the severity of TTS takes, is expected to 
be low-level, of short duration, and mostly not in a frequency band 
that would be expected to interfere significantly with conspecific 
communication, echolocation, or other important low-frequency cues. 
Therefore, the associated lost opportunities and capabilities would not 
be expected to impact reproduction or survival. For these same reasons 
(low level and the likely frequency band), while a small permanent loss 
of hearing sensitivity may include some degree of energetic costs for 
compensating or may mean some small loss of opportunities or detection 
capabilities, the estimated 209 Level A harassment takes by PTS for 
Dall's porpoise would be unlikely to impact behaviors, opportunities, 
or detection capabilities to a degree that would interfere with 
reproductive success or survival for most individuals. Because of the 
high number of PTS takes, however, we acknowledge that a few animals 
could potentially incur permanent hearing loss of a higher degree that 
could potentially interfere with their successful reproduction and 
growth. Given the status of the stock, even if this occurred, it would 
not adversely impact rates of recruitment or survival.
    Altogether, a portion of this stock will likely be taken (at a low 
to occasionally moderate level) over several days a year, and some 
smaller portion of the stock is expected to be taken on a relatively 
moderate to high number of days across the year, some of which could be 
sequential days. Though the majority of impacts are expected to be of a 
lower to sometimes moderate severity, the larger number of takes (in 
total and for certain individuals) for the Dall's porpoise makes it 
more likely (probabilistically) that a small number of individuals 
could be interrupted during foraging in a manner and amount such that 
impacts to the energy budgets of females (from either losing feeding 
opportunities or expending considerable energy to find alternative 
feeding options) could cause them to forego reproduction for a year. 
Energetic impacts to males are generally meaningless to population 
rates unless they cause death, and it takes extreme energy deficits 
beyond what would ever be likely to result from these activities to 
cause the death of an adult marine mammal. Similarly, we acknowledge 
the potential for this to occur to a few individuals out of the 209 
total that might incur a higher degree of PTS. As noted previously, 
however, foregone reproduction (especially for only one year in five) 
has far less of an impact on population rates than mortality. Further, 
the small number of instances of foregone reproduction that could 
potentially result from PTS and/or the few repeated, more severe 
behavioral harassment takes would not be expected to adversely affect 
the stock through effects on annual rates of recruitment or survival, 
especially given the status of the species (not endangered or 
threatened; minimum population of 25,170 just within the U.S. EEZ) and 
residual PBR of Dall's porpoise (171.4). For these reasons, in 
consideration of all of the effects of the Navy's activities combined, 
we have determined that the authorized take will have a negligible 
impact on Dall's porpoise.
Pinnipeds
    In this section, we build on the broader discussion above and bring 
together the discussion of the different types and amounts of take that 
different species and stocks will incur, the applicable mitigation for 
each stock, and the status of the stocks to support the negligible 
impact determinations for each stock. Of these stocks, only Hawaiian 
monk seals and Guadalupe fur seals are listed under the ESA (endangered 
and threatened, respectively) and the SARs identify both stocks as 
``increasing.'' The other stocks are not ESA-listed. All of the 
pinniped stocks are considered ``increasing,'' except for harbor seal 
(California stock), which is considered stable, and Hawaiian monk 
seals, which are increasing in the main Hawaiian islands, but 
decreasing in the Northwest Hawaiian islands (the SAR says that 
therefore they are not certain whether to consider the whole stock as 
decreasing, stable, or possible increasing). Broadly, we have already 
described above why we believe the incremental addition of the 
comparatively small number of low-level PTS takes in predominantly 
narrow frequency bands will not have any meaningful effect towards 
inhibiting reproduction or survival. Other than for California sea 
lions, no mortality is expected or authorized. We have described (above 
in this section and in the proposed rule, respectively, with no new 
applicable information received since publication of the proposed rule) 
the unlikelihood of any masking or habitat impacts to any groups that 
would rise to the level of affecting reproduction or survival.
    In Tables 80 and 81 below, for pinnipeds, we indicate the total 
annual mortality, Level A and Level B harassment, and a number 
indicating the instances of total take as a percentage of abundance.
BILLING CODE 3510-22-P

[[Page 67016]]

[GRAPHIC] [TIFF OMITTED] TR27DE18.039

[GRAPHIC] [TIFF OMITTED] TR27DE18.040

BILLING CODE 3510-22-C
    The majority of takes by harassment of pinnipeds in the HSTT Study 
Area are caused by sources from the MF1 active sonar bin (which 
includes hull-mounted sonar) because they are high level sources at a 
frequency (1-10 kHz) which overlaps the most sensitive portion of the 
pinniped hearing range, and of the sources expected to result in take, 
they are used in a large portion of exercises (see Table 1.5-5 in the 
Navy's rulemaking/LOA application). Most of the takes (83 percent) from 
the MF1 bin in the HSTT Study Area would result from received levels 
between 160 and 172 dB SPL, while another 16 percent would result from 
exposure between 172 and 178 dB SPL. For the remaining active sonar bin 
types, the percentages are as follows: LF3 = 92 percent between 154 and 
166 dB SPL, LF5M = 99 percent between 112 and 124 dB SPL, MF4 = 98 
percent between 148 and 166 dB SPL, MF5 = 97 percent between 130 and 
160 dB SPL, and HF4 = 96 percent between 100 and 160 dB SPL. These 
values may be derived from the information in Tables 6.4-8 through 6.4-
12 in the Navy's rulemaking/LOA application (though they were provided 
directly to NMFS upon request). Exposures at these levels would be 
considered of low to occasionally moderate severity. As mentioned 
earlier in this section, we anticipate more severe effects from takes 
when animals are exposed to higher received levels. Occasional milder 
takes by Level B behavioral harassment are unlikely to cause long-term 
consequences for individual animals or populations, especially when 
they are not expected to be repeated over sequential multiple days. For 
all pinnipeds, harassment takes from explosives (behavioral, TTS, or 
PTS if present) comprise a very small fraction of those caused by 
exposure to active sonar. No PTS is expected to result from pile 
driving or air guns for pinnipeds and TTS from pile driving and air 
guns is limited to single digits for elephant seals.
    Because the majority of harassment take of pinnipeds results from 
narrowband sources in the range of 1-10 kHz, the vast majority of 
threshold shift caused by Navy sonar sources will typically occur in 
the range of 2-20 kHz. This frequency range falls within the range of 
pinniped hearing, however, pinniped vocalizations typically span a 
somewhat lower range than this (<0.2 to 10 kHz) and threshold shift 
from active sonar will often be in a narrower band (reflecting the 
narrower band source that caused it), which means that TTS incurred by 
pinnipeds would typically only interfere with communication within a 
portion of a pinniped's range (if it occurred during a time when 
communication with conspecifics was

[[Page 67017]]

occurring). As discussed earlier, it would only be expected to be of a 
short duration and relatively small degree. Many of the other critical 
sounds that serve as cues for navigation and prey (e.g., waves, fish, 
invertebrates) occur below a few kHz, which means that detection of 
these signals will not be inhibited by most threshold shifts either. 
The very low number of takes by threshold shifts that might be incurred 
by individuals exposed to explosives or air guns would likely be lower 
frequency (5 kHz or less) and spanning a wider frequency range, which 
could slightly lower an individual's sensitivity to navigational or 
prey cues, or a small portion of communication calls, for several 
minutes to hours (if temporary) or permanently.
    We note that as described previously, the Hawaii and 4-Islands 
mitigation areas protect (by not using explosives and limiting MFAS 
within) a significant portion of the designated critical habitat for 
Hawaiian monk seals in the Main Hawaiian Islands, including all of it 
around the islands of Hawaii and Lanai, most around Maui, and good 
portions around Molokai and Kaho'olawe. As discussed, this protection 
reduces the overall number of takes, and further reduces the severity 
of effects by minimizing impacts near pupping beaches and in important 
foraging habitat.
    Regarding behavioral disturbance, research and observations show 
that pinnipeds in the water may be tolerant of anthropogenic noise and 
activity (a review of behavioral reactions by pinnipeds to impulsive 
and non-impulsive noise can be found in Richardson et al. (1995) and 
Southall et al. (2007). Available data, though limited, suggest that 
exposures between approximately 90 and 140 dB SPL do not appear to 
induce strong behavioral responses in pinnipeds exposed to non-pulse 
sounds in water (Costa et al., 2003; Jacobs and Terhune, 2002; 
Kastelein et al., 2006c). Based on the limited data on pinnipeds in the 
water exposed to multiple pulses (small explosives, impact pile 
driving, and seismic sources), exposures in the approximately 150 to 
180 dB SPL range generally have limited potential to induce avoidance 
behavior in pinnipeds (Blackwell et al., 2004; Harris et al., 2001; 
Miller et al., 2004). If pinnipeds are exposed to sonar or other active 
acoustic sources they may react in a number of ways depending on their 
experience with the sound source and what activity they are engaged in 
at the time of the acoustic exposure. Pinnipeds may not react at all 
until the sound source is approaching within a few hundred meters and 
then may alert, ignore the stimulus, change their behaviors, or avoid 
the immediate area by swimming away or diving. Effects on pinnipeds in 
the HSTT Study Area that are taken by Level B harassment, on the basis 
of reports in the literature as well as Navy monitoring from past 
activities, will likely be limited to reactions such as increased 
swimming speeds, increased surfacing time, or decreased foraging (if 
such activity were occurring). Most likely, individuals will simply 
move away from the sound source and be temporarily displaced from those 
areas, or not respond at all, which would have no effect on 
reproduction or survival. In areas of repeated and frequent acoustic 
disturbance, some animals may habituate or learn to tolerate the new 
baseline or fluctuations in noise level. Habituation can occur when an 
animal's response to a stimulus wanes with repeated exposure, usually 
in the absence of unpleasant associated events (Wartzok et al., 2003). 
While some animals may not return to an area, or may begin using an 
area differently due to training and testing activities, most animals 
are expected to return to their usual locations and behavior. Given 
their documented tolerance of anthropogenic sound (Richardson et al., 
1995 and Southall et al., 2007), repeated exposures of individuals of 
any of these species to levels of sound that may cause Level B 
harassment are unlikely to result in hearing impairment or to 
significantly disrupt foraging behavior.
    Thus, even repeated Level B harassment of some small subset of 
individuals of an overall stock is unlikely to result in any 
significant realized decrease in fitness to those individuals that 
would result in any adverse impact on rates of recruitment or survival 
for the stock as a whole.
    The Navy is authorized for four M/SI takes of California sea lions 
and when this mortality is combined with the other human-caused 
mortality from other sources, it still falls well below the 
insignificance threshold for residual PBR. A small number of Level A 
harassment takes by tissue damage will also be authorized (9 and 2 for 
California sea lions and northern elephant seals, respectively), which, 
as noted previously, could range in impact from minor to something just 
less than M/SI that could seriously impact fitness. However, given the 
Navy's mitigation, exposure at the closer to the source and more severe 
end of the spectrum is less likely. Nevertheless, we cautiously assume 
some moderate impact on the individuals that experience these small 
numbers of take that could lower the individual's fitness within the 
year such that a female (assuming a 50 percent chance of it being a 
female) might forego reproduction for one year. As noted previously, 
foregone reproduction has less of an impact on population rates than 
death (especially for only one within five years) and these low numbers 
of instances (especially assuming the likelihood that only 50 percent 
of the takes would affect females) would not be expected to impact 
annual rates of recruitment or survival, especially given the 
population sizes of these species.
    Regarding the magnitude of Level B harassment takes (TTS and 
behavioral disruption), for Hawaiian monk seals and Guadalupe fur 
seals, the two species listed under the ESA, the estimated instances of 
takes as compared to the stock abundance does not exceed 124 percent, 
which suggests that some portion of these two stocks would be taken on 
one to a few days per year. For the remaining stocks, the number of 
estimated total instances of take compared to the abundance (measured 
against both the Navy-estimated abundance and the SAR) for these stocks 
is 1,484-2,896 percent and 18-40 percent, respectively (Table 81). 
Given the ranges of these stocks (i.e., very large ranges, but with 
individuals often staying in the vicinity of haulouts), this 
information suggests that some very small portion of the individuals of 
these stocks will be taken, but that some subset of individuals within 
the stock will be taken repeatedly within the year (perhaps up to 58 
days)--potentially over a fair number of sequential days. Regarding the 
severity of those individual takes by Level B behavioral harassment, we 
have explained that the duration of any exposure is expected to be 
between minutes and hours (i.e., relatively short) and the received 
sound levels largely below 172 dB, which is considered a relatively low 
to occasionally moderate level for pinnipeds. However, as noted, some 
of these takes could occur on a fair number of sequential days for this 
stock.
    As described previously, the severity of TTS takes, expected to be 
low-level, of short duration, and mostly not in a frequency band that 
would be expected to interfere significantly with conspecific 
communication, echolocation, or other important low-frequency cues that 
would affect the individual's reproduction or survival. For these same 
reasons (low level and frequency band), while a small permanent loss of 
hearing sensitivity may include some degree of energetic costs for 
compensating or may mean

[[Page 67018]]

some small loss of opportunities or detection capabilities, the one to 
eight estimated Level A harassment takes by PTS for monk seals, 
northern fur seals, and harbor seals would be unlikely to impact 
behaviors, opportunities, or detection capabilities to a degree that 
would interfere with reproductive success or survival of any 
individuals. Because of the high number of PTS takes for California sea 
lions and northern elephant seals (87 and 97, respectively); however, 
we acknowledge that a few animals could potentially incur permanent 
hearing loss of a higher degree that could potentially interfere with 
their successful reproduction and growth. Given the status of the 
stock, even if this occurred, it would not adversely impact rates of 
recruitment or survival (residual PBR of 13,686 and 4,873, 
respectively).
    Altogether, Hawaiian monk seals and Guadalupe fur seals individuals 
will be taken no more than a few days in any year, with none of the 
expected take anticipated to affect individual reproduction or 
survival, let alone annual rates of recruitment and survival. With all 
other stocks, only a very small portion of the stock will be taken in 
any manner. Of those taken, some individuals will be taken by Level B 
harassment (at a moderate or sometimes low level) over several days a 
year, and some smaller portion of those taken will be on a relatively 
moderate to high number of days across the year (up to 58), a fair 
number of which would likely be sequential days. Though the majority of 
impacts are expected to be of a lower to sometimes moderate severity, 
the repeated takes over a potentially fair number of sequential days 
for some individuals makes it more likely that some number of 
individuals could be interrupted during foraging in a manner and amount 
such that impacts to the energy budgets of females (from either losing 
feeding opportunities or expending considerable energy to find 
alternative feeding options) could cause them to forego reproduction 
for a year (energetic impacts to males are generally meaningless to 
population rates unless they cause death, and it takes extreme energy 
deficits beyond what would ever be likely to result from these 
activities to cause the death of an adult marine mammal). As noted 
previously, however, foregone reproduction (especially for only one 
year within five) has far less of an impact on population rates than 
mortality and a relatively small number of instances of foregone 
reproduction (as compared to the stock abundance and residual PBR) 
would not be expected to adversely affect the stock through effects on 
annual rates of recruitment or survival, especially given the status of 
these stocks. Accordingly, we do not anticipate the relatively small 
number of individual Northern fur seals or harbor seals that might be 
taken over repeated days within the year in a manner that results in 
one year of foregone reproduction to adversely affect the stocks 
through effects on rates of recruitment or survival, given the status 
of the stocks, which are respectively increasing and stable with 
abundances and residual PBRs of 14,050/30,968 and 449/1,598.
    For California sea lions, given the very high abundance and 
residual PBR (296,750 and 13,686), as well as the increasing status of 
the stock in the presence of similar levels of Navy activities over 
past years--the impacts of 0.2 annual mortalities, potential foregone 
reproduction for up to nine individuals in a year taken by tissue 
damage and some relatively small number of individuals taken as a 
result of repeated behavioral harassment over a fair number of 
sequential days are not expected to adversely affect the stock through 
effects on annual rates of recruitment or survival. similarly, for 
Northern elephant seals, given the very high abundance and residual PBR 
(179,000 and 4,873), as well as the increasing status of the stock in 
the presence of similar levels of Navy activities over past years--the 
impacts of potential foregone reproduction for up to two individuals in 
a year taken by tissue damage and some relatively small number of 
individuals taken as a result of repeated behavioral harassment over a 
fair number of sequential days are not expected to adversely affect the 
stock through effects on annual rates of recruitment or survival. For 
these reasons, in consideration of all of the effects of the Navy's 
activities combined (mortality, Level A harassment, and Level B 
harassment), we have determined that the authorized take will have a 
negligible impact on all pinniped species and stocks (Tables 80 and 
81).

Determination

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

Subsistence Harvest of Marine Mammals

    There are no relevant subsistence uses or harvest of marine mammals 
implicated by this action. Therefore, NMFS has 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 nine marine mammal species under NMFS jurisdiction that 
are listed as endangered or threatened under the ESA with confirmed or 
possible occurrence in the HSTT Study Area: Blue whale (Eastern and 
Central North Pacific stocks), fin whale (CA/OR/WA and Hawaii stocks), 
gray whale (Western North Pacific stock), humpback whale (Mexico and 
Central America DPSs), sei whale (Eastern North Pacific and Hawaii 
stocks), sperm whale (CA/OR/WA and Hawaii stocks), false killer whale 
(Main Hawaii Islands Insular), Hawaiian monk seal (Hawaii stock), and 
Guadalupe fur seal (Mexico to California). There is also ESA-designated 
critical habitat for Hawaiian monk seals and Main Hawaiian Island 
insular false killer whales. The Navy consulted with NMFS pursuant to 
section 7 of the ESA, and NMFS also consulted internally on the 
issuance of these regulations and LOAs under section 101(a)(5)(A) of 
the MMPA for HSTT activities. NMFS issued a Biological Opinion 
concluding that the issuance of the rule and subsequent LOAs is not 
likely to jeopardize the continued existence of the threatened and 
endangered species under NMFS' jurisdiction and are not likely to 
result in the destruction or adverse modification of critical habitat 
in the HSTT Study Area. The Biological Opinion for this action is 
available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.

National Marine Sanctuaries Act

    Federal agencies are subject to the National Marine Sanctuaries Act 
(NMSA), as applicable. NMFS has fulfilled its responsibilities and 
completed all requirements under the NMSA.

National Environmental Policy Act

    NMFS participated as a cooperating agency on the HSTT FEIS/OEIS, 
which was published on October 26, 2018, and is available at https://www.hstteis.com/. In accordance with 40 CFR 1506.3, NMFS independently 
reviewed and

[[Page 67019]]

evaluated the HSTT FEIS/OEIS and determined that it is adequate and 
sufficient to meet our responsibilities under NEPA for the issuance of 
this rule and associated LOAs. NOAA therefore adopted the Navy's HSTT 
FEIS/OEIS. NMFS has prepared a separate Record of Decision. NMFS' 
Record of Decision for adoption of the HSTT FEIS/OEIS and issuance of 
this final rule and subsequent LOAs can be found at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.

Classification

    The Office of Management and Budget has determined that this final 
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 
final rule will not have a significant economic impact on a substantial 
number of small entities. The RFA requires Federal agencies to prepare 
an analysis of a rule's impact on small entities whenever the agency is 
required to publish a notice of proposed rulemaking. However, a Federal 
agency may certify, pursuant to 5 U.S.C. 605(b), that the action will 
not have a significant economic impact on a substantial number of small 
entities. The Navy is the sole entity that would be affected by this 
rulemaking, and the Navy is not a small governmental jurisdiction, 
small organization, or small business, as defined by the RFA. Any 
requirements imposed by an LOA issued pursuant to these regulations, 
and any monitoring or reporting requirements imposed by these 
regulations, would be applicable only to the Navy. Because this action 
will directly affect the Navy and not a small entity, NMFS concludes 
the action will not result in a significant economic impact on a 
substantial number of small entities.

Waiver of Delay in Effective Date

    NMFS has determined that there is good cause under the 
Administrative Procedure Act (5 U.S.C 553(d)(3)) to waive the 30-day 
delay in the effective date of this final rule. No individual or entity 
other than the Navy is affected by the provisions of these regulations. 
The Navy has informed NMFS that it requests that this final rule take 
effect on or by December 21, 2018, to accommodate the Navy's current 
LOAs expiring December 24, 2018, so as to not cause a disruption in 
training and testing activities. NMFS was unable to accommodate the 30-
day delay of effectiveness period due to the need for additional time 
to consider additional mitigation measures presented by the Navy as 
well as new analysis of information showing that incidental mortality 
and serious injury of seven stocks previously analyzed is unlikely to 
occur. The waiver of the 30-day delay of the effective date of the 
final rule will ensure that the MMPA final rule and LOAs are in place 
by the time the previous authorizations expire. Any delay in finalizing 
the rule would result in either: (1) A suspension of planned naval 
training and testing, which would disrupt vital training and testing 
essential to national security; or (2) the Navy's procedural non-
compliance with the MMPA (should the Navy conduct training and testing 
without LOAs), thereby resulting in the potential for unauthorized 
takes of marine mammals. Moreover, the Navy is ready to implement the 
rule immediately. For these reasons, NMFS finds good cause to waive the 
30-day delay in the effective date. In addition, the rule authorizes 
incidental take of marine mammals that would otherwise be prohibited 
under the statute. Therefore the rule is granting an exception to the 
Navy and relieving restrictions under the MMPA, which is a separate 
basis for waiving the 30-day effective date for the rule.

List of Subjects in 50 CFR Part 218

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

    Dated: December 13, 2018.
Alan D. Risenhoover,
Acting Deputy Assistant Administrator for Regulatory Programs, National 
Marine Fisheries Service.

    For reasons set forth in the preamble, 50 CFR part 218 is amended 
as follows:

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

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

    Authority: 16 U.S.C. 1361 et seq., unless otherwise noted.


0
2. Revise subpart H to part 218 to read as follows:
Subpart H--Taking and Importing Marine Mammals; U.S. Navy's Hawaii-
Southern California Training and Testing (HSTT)
Sec.
218.70 Specified activity and geographical region.
218.71 Effective dates.
218.72 Permissible methods of taking.
218.73 Prohibitions.
218.74 Mitigation requirements.
218.75 Requirements for monitoring and reporting.
218.76 Letters of Authorization.
218.77 Renewals and modifications of Letters of Authorization.
218.78 [Reserved]
218.79 [Reserved]

Subpart H--Taking and Importing Marine Mammals; U.S. Navy's Hawaii-
Southern California Training and Testing (HSTT)


Sec.  218.70  Specified activity and geographical region.

    (a) Regulations in this subpart apply only to the U.S. Navy for the 
taking of marine mammals that occurs in the area described in paragraph 
(b) of this section and that occurs incidental to the activities listed 
in paragraph (c) of this section.
    (b) The taking of marine mammals by the Navy under this subpart may 
be authorized in Letters of Authorization (LOAs) only if it occurs 
within the Hawaii-Southern California Training and Testing (HSTT) Study 
Area, which includes established operating and warning areas across the 
north-central Pacific Ocean, from the mean high tide line in Southern 
California west to Hawaii and the International Date Line. The Study 
Area includes the at-sea areas of three existing range complexes the 
Hawaii Range Complex (HRC), the Southern California Range Complex 
(SOCAL), and the Silver Strand Training Complex, and overlaps a portion 
of the Point Mugu Sea Range (PMSR). Also included in the Study Area are 
Navy pierside locations in Hawaii and Southern California, Pearl 
Harbor, San Diego Bay, and the transit corridor on the high seas where 
sonar training and testing may occur.
    (c) The taking of marine mammals by the Navy is only authorized if 
it occurs incidental to the Navy conducting training and testing 
activities, including:
    (1) Training. (i) Amphibious warfare;
    (ii) Anti-submarine warfare;
    (iii) Electronic warfare;
    (iv) Expeditionary warfare;
    (v) Mine warfare; and
    (vi) Surface warfare.
    (2) Testing. (i) Naval Air Systems Command Testing Activities;
    (ii) Naval Sea System Command Testing Activities; and
    (iii) Office of Naval Research Testing Activities.

[[Page 67020]]

Sec.  218.71   Effective dates.

    Regulations in this subpart are effective December 21, 2018 through 
December 20, 2023.


Sec.  218.72  Permissible methods of taking.

    (a) Under LOAs issued pursuant to Sec. Sec.  216.106 of this 
chapter and 218.76, the Holder of the LOAs (hereinafter ``Navy'') may 
incidentally, but not intentionally, take marine mammals within the 
area described in Sec.  218.70(b) by Level A harassment and Level B 
harassment associated with the use of active sonar and other acoustic 
sources and explosives as well as serious injury or mortality 
associated with vessel strikes and explosives, provided the activity is 
in compliance with all terms, conditions, and requirements of these 
regulations in this subpart and the applicable LOAs.
    (b) The incidental take of marine mammals by the activities listed 
in Sec.  218.80(c) is limited to the following species:

                        Table 1 to Sec.   218.72
------------------------------------------------------------------------
                Species                               Stock
------------------------------------------------------------------------
Blue whale.............................  Central North Pacific.
Blue whale.............................  Eastern North Pacific.
Bryde's whale..........................  Eastern Tropical Pacific.
Bryde's whale..........................  Hawaii.
Fin whale..............................  CA/OR/WA.
Fin whale..............................  Hawaiian.
Humpback whale.........................  CA/OR/WA.
Humpback whale.........................  Central North Pacific.
Minke whale............................  CA/OR/WA.
Minke whale............................  Hawaii.
Sei whale..............................  Eastern North Pacific.
Sei whale..............................  Hawaii.
Gray whale.............................  Eastern North Pacific.
Gray whale.............................  Western North Pacific.
Sperm whale............................  CA/OR/WA.
Sperm whale............................  Hawaii.
Dwarf sperm whale......................  Hawaii.
Pygmy sperm whale......................  Hawaii.
Kogia whales...........................  CA/OR/WA.
Baird's beaked whale...................  CA/OR/WA.
Blainville's beaked whale..............  Hawaii.
Cuvier's beaked whale..................  CA/OR/WA.
Cuvier's beaked whale..................  Hawaii.
Longman's beaked whale.................  Hawaii.
Mesoplodon spp.........................  CA/OR/WA.
Bottlenose dolphin.....................  California Coastal.
Bottlenose dolphin.....................  CA/OR/WA Offshore.
Bottlenose dolphin.....................  Hawaii Pelagic.
Bottlenose dolphin.....................  Kauai & Niihau.
Bottlenose dolphin.....................  Oahu.
Bottlenose dolphin.....................  4-Island.
Bottlenose dolphin.....................  Hawaii.
False killer whale.....................  Hawaii Pelagic.
False killer whale.....................  Main Hawaiian Islands Insular.
False killer whale.....................  Northwestern Hawaiian Islands.
Fraser's dolphin.......................  Hawaii.
Killer whale...........................  Eastern North Pacific (ENP)
                                          Offshore.
Killer whale...........................  ENP Transient/West Coast
                                          Transient.
Killer whale...........................  Hawaii.
Long-beaked common dolphin.............  California.
Melon-headed whale.....................  Hawaiian Islands.
Melon-headed whale.....................  Kohala Resident.
Northern right whale dolphin...........  CA/OR/WA.
Pacific white-sided dolphin............  CA/OR/WA.
Pantropical spotted dolphin............  Hawaii Island.
Pantropical spotted dolphin............  Hawaii Pelagic.
Pantropical spotted dolphin............  Oahu.
Pantropical spotted dolphin............  4-Island.
Pygmy killer whale.....................  Hawaii.
Pygmy killer whale.....................  Tropical.
Risso's dolphin........................  CA/OR/WA.
Risso's dolphin........................  Hawaii.
Rough-toothed dolphin..................  Hawaii.
Short-beaked common dolphin............  CA/OR/WA.
Short-finned pilot whale...............  CA/OR/WA.
Short-finned pilot whale...............  Hawaii.
Spinner dolphin........................  Hawaii Island.
Spinner dolphin........................  Hawaii Pelagic.
Spinner dolphin........................  Kauai & Niihau.
Spinner dolphin........................  Oahu & 4-Island.
Striped dolphin........................  CA/OR/WA.

[[Page 67021]]

 
Striped dolphin........................  Hawaii.
Dall's porpoise........................  CA/OR/WA.
California sea lion....................  U.S.
Guadalupe fur seal.....................  Mexico.
Northern fur seal......................  California.
Harbor seal............................  California.
Hawaiian monk seal.....................  Hawaii.
Northern elephant seal.................  California.
------------------------------------------------------------------------
Note to Table 1: CA/OR/WA = California/Oregon/Washington.

Sec.  218.73  Prohibitions.

    Notwithstanding incidental takings contemplated in Sec.  218.72(a) 
and authorized by LOAs issued under Sec. Sec.  216.106 of this chapter 
and 218.76, no person in connection with the activities listed in Sec.  
218.70(c) may:
    (a) Violate, or fail to comply with, the terms, conditions, and 
requirements of this subpart or an LOA issued under Sec. Sec.  216.106 
of this chapter and 218.76;
    (b) Take any marine mammal not specified in Sec.  218.72(b);
    (c) Take any marine mammal specified in Sec.  218.72(b) in any 
manner other than as specified in the LOAs; or
    (d) Take a marine mammal specified in Sec.  218.72(b) if NMFS 
determines such taking results in more than a negligible impact on the 
species or stocks of such marine mammal.


Sec.  218.74  Mitigation requirements.

    When conducting the activities identified in Sec.  218.70(c), the 
mitigation measures contained in any LOAs issued under Sec. Sec.  
216.106 of this chapter and 218.76 must be implemented. These 
mitigation measures include, but are not limited to:
    (a) Procedural mitigation. Procedural mitigation is mitigation that 
the Navy must implement whenever and wherever an applicable training or 
testing activity takes place within the HSTT Study Area for each 
applicable activity category or stressor category and includes acoustic 
stressors (i.e., active sonar, air guns, pile driving, weapons firing 
noise), explosive stressors (i.e., sonobuoys, torpedoes, medium-caliber 
and large-caliber projectiles, missiles and rockets, bombs, sinking 
exercises, mines, anti-swimmer grenades, and mat weave and obstacle 
loading), and physical disturbance and strike stressors (i.e., vessel 
movement; towed in-water devices; small-, medium-, and large-caliber 
non-explosive practice munitions; non-explosive missiles and rockets; 
and non-explosive bombs and mine shapes).
    (1) Environmental awareness and education. Appropriate Navy 
personnel (including civilian personnel) involved in mitigation and 
training or testing activity reporting under the specified activities 
must complete one or more modules of the U.S Navy Afloat Environmental 
Compliance Training Series, as identified in their career path training 
plan. Modules include: Introduction to the U.S. Navy Afloat 
Environmental Compliance Training Series, Marine Species Awareness 
Training; U.S. Navy Protective Measures Assessment Protocol; and U.S. 
Navy Sonar Positional Reporting System and Marine Mammal Incident 
Reporting.
    (2) Active sonar. Active sonar includes low-frequency active sonar, 
mid-frequency active sonar, and high-frequency active sonar. For 
vessel-based activities, mitigation applies only to sources that are 
positively controlled and deployed from manned surface vessels (e.g., 
sonar sources towed from manned surface platforms). For aircraft-based 
activities, mitigation applies only to sources that are positively 
controlled and deployed from manned aircraft that do not operate at 
high altitudes (e.g., rotary-wing aircraft). Mitigation does not apply 
to active sonar sources deployed from unmanned aircraft or aircraft 
operating at high altitudes (e.g., maritime patrol aircraft).
    (i) Number of Lookouts and observation platform--(A) Hull-mounted 
sources. One Lookout for platforms with space or manning restrictions 
while underway (at the forward part of a small boat or ship) and 
platforms using active sonar while moored or at anchor (including 
pierside); and two Lookouts for platforms without space or manning 
restrictions while underway (at the forward part of the ship).
    (B) Sources that are not hull-mounted sources. One Lookout on the 
ship or aircraft conducting the activity.
    (ii) Mitigation zone and requirements. During the activity, at 
1,000 yards (yd) Navy personnel must power down 6 decibels (dB), at 500 
yd Navy personnel must power down an additional 4 dB (for a total of 10 
dB), and 200 yd Navy personnel must shut down for low-frequency active 
sonar >=200 dB and hull-mounted mid-frequency active sonar; or at 200 
yd Navy personnnel must shut down for low-frequency active sonar <200 
dB, mid-frequency active sonar sources that are not hull-mounted, and 
high-frequency active sonar.
    (A) Prior to the start of the activity (e.g., when maneuvering on 
station), Navy personnel must observe the mitigation zone for floating 
vegetation; if floating vegetation is observed, Navy personnel must 
relocate or delay the start of active sonar transmission until the 
mitigation zone is clear. Navy personnel must also observe the 
mitigation zone for marine mammals; if marine mammals are observed, 
Navy personnel must relocate or delay the start of active sonar 
transmission.
    (B) During the activity for low-frequency active sonar at or above 
200 dB and hull-mounted mid-frequency active sonar, Navy personnel must 
observe the mitigation zone for marine mammals and power down active 
sonar transmission by 6 dB if marine mammals are observed within 1,000 
yd of the sonar source; power down by an additional 4 dB (for a total 
of 10 dB total) if marine mammals are observed within 500 yd of the 
sonar source; and cease transmission if marine mammals are observed 
within 200 yd of the sonar source.
    (C) During the activity for low-frequency active sonar below 200 
dB, mid-frequency active sonar sources that are not hull mounted, and 
high-frequency active sonar, Navy personnel must observe the mitigation 
zone for marine mammals and cease active sonar transmission if marine 
mammals are observed within 200 yd of the sonar source.
    (D) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing or

[[Page 67022]]

powering up active sonar transmission) until one of the following 
conditions has been met: The animal is observed exiting the mitigation 
zone; the animal is thought to have exited the mitigation zone based on 
a determination of its course, speed, and movement relative to the 
sonar source; the mitigation zone has been clear from any additional 
sightings for 10 minutes (min) for aircraft-deployed sonar sources or 
30 min for vessel-deployed sonar sources; for mobile activities, the 
active sonar source has transited a distance equal to double that of 
the mitigation zone size beyond the location of the last sighting; or 
for activities using hull-mounted sonar where a dolphin(s) is observed 
in the mitigation zone, the Lookout concludes that the dolphin(s) are 
deliberately closing in on the ship to ride the ship's bow wave, and 
are therefore out of the main transmission axis of the sonar (and there 
are no other marine mammal sightings within the mitigation zone).
    (3) Air guns--(i) Number of Lookouts and observation platform. One 
Lookout positioned on a ship or pierside.
    (ii) Mitigation zone and requirements. 150 yd around the air gun.
    (A) Prior to the initial start of the activity (e.g., when 
maneuvering on station), Navy personnel must observe the mitigation 
zone for floating vegetation; if floating vegetation is observed, Navy 
personnel must relocate or delay the start until the mitigation zone is 
clear. Navy personnel must also observe the mitigation zone for marine 
mammals; if marine mammals are observed, Navy personnel must relocate 
or delay the start of air gun use.
    (B) During the activity, Navy personnel must observe the mitigation 
zone for marine mammals; if marine mammals are observed, Navy personnel 
must cease air gun use.
    (C) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing air gun use) until one of the following conditions 
has been met: The animal is observed exiting the mitigation zone; the 
animal is thought to have exited the mitigation zone based on a 
determination of its course, speed, and movement relative to the air 
gun; the mitigation zone has been clear from any additional sightings 
for 30 min; or for mobile activities, the air gun has transited a 
distance equal to double that of the mitigation zone size beyond the 
location of the last sighting.
    (4) Pile driving. Pile driving and pile extraction sound during 
Elevated Causeway System training.
    (i) Number of Lookouts and observation platform. One Lookout must 
be positioned on the shore, the elevated causeway, or a small boat.
    (ii) Mitigation zone and requirements. 100 yd around the pile 
driver.
    (A) Prior to the initial start of the activity (for 30 min), Navy 
personnel must observe the mitigation zone for floating vegetation; if 
floating vegetation is observed, Navy personnel must delay the start 
until the mitigation zone is clear. Navy personnel also must observe 
the mitigation zone for marine mammals; if marine mammals are observed, 
Navy personnel must delay the start of pile driving or vibratory pile 
extraction.
    (B) During the activity, Navy personnel must observe the mitigation 
zone for marine mammals; if marine mammals are observed, Navy personnel 
must cease impact pile driving or vibratory pile extraction.
    (C) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. The Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing pile driving or pile extraction) until one of the 
following conditions has been met: The animal is observed exiting the 
mitigation zone; the animal is thought to have exited the mitigation 
zone based on a determination of its course, speed, and movement 
relative to the pile driving location; or the mitigation zone has been 
clear from any additional sightings for 30 min.
    (5) Weapons firing noise. Weapons firing noise associated with 
large-caliber gunnery activities.
    (i) Number of Lookouts and observation platform. One Lookout must 
be positioned on the ship conducting the firing. Depending on the 
activity, the Lookout could be the same as the one provided for under 
``Explosive medium-caliber and large-caliber projectiles'' or under 
``Small-, medium-, and large-caliber non-explosive practice munitions'' 
in paragraphs (a)(8)(i) and (a)(18)(i) of this section.
    (ii) Mitigation zone and requirements. Thirty degrees on either 
side of the firing line out to 70 yd from the muzzle of the weapon 
being fired.
    (A) Prior to the start of the activity, Navy personnel must observe 
the mitigation zone for floating vegetation; if floating vegetation is 
observed, Navy personnel must relocate or delay the start of weapons 
firing until the mitigation zone is clear. Navy personnel must also 
observe the mitigation zone for marine mammals; if marine mammals are 
observed, Navy personnel must relocate or delay the start of weapons 
firing.
    (B) During the activity, Navy personnel must observe the mitigation 
zone for marine mammals; if marine mammals are observed, Navy personnel 
must cease weapons firing.
    (C) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing weapons firing) until one of the following 
conditions has been met: The animal is observed exiting the mitigation 
zone; the animal is thought to have exited the mitigation zone based on 
a determination of its course, speed, and movement relative to the 
firing ship; the mitigation zone has been clear from any additional 
sightings for 30 min; or for mobile activities, the firing ship has 
transited a distance equal to double that of the mitigation zone size 
beyond the location of the last sighting.
    (6) Explosive sonobuoys--(i) Number of Lookouts and observation 
platform. One Lookout must be positioned in an aircraft or on small 
boat. If additional platforms are participating in the activity, Navy 
personnel positioned in those assets (e.g., safety observers, 
evaluators) must support observing the mitigation zone for applicable 
biological resources while performing their regular duties.
    (ii) Mitigation zone and requirements. 600 yd around an explosive 
sonobuoy.
    (A) Prior to the initial start of the activity (e.g., during 
deployment of a sonobuoy field, which typically lasts 20-30 min), Navy 
personnel must observe the mitigation zone for floating vegetation; if 
floating vegetation is observed, Navy personnel must relocate or delay 
the start of sonobuoy or source/receiver pair detonations until the 
mitigation zone is clear. Navy personnel must conduct passive acoustic 
monitoring for marine mammals and use information from detections to 
assist visual observations. Navy personnel also must visually observe 
the mitigation zone for marine mammals; if marine mammals are observed, 
Navy personnel must relocate or delay the start of sonobuoy or source/
receiver pair detonations.
    (B) During the activity, Navy personnel must observe the mitigation 
zone for marine mammals; if marine

[[Page 67023]]

mammals are observed, Navy personnel must cease sonobuoy or source/
receiver pair detonations.
    (C) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing detonations) until one of the following conditions 
has been met: The animal is observed exiting the mitigation zone; the 
animal is thought to have exited the mitigation zone based on a 
determination of its course, speed, and movement relative to the 
sonobuoy; or the mitigation zone has been clear from any additional 
sightings for 10 min when the activity involves aircraft that have fuel 
constraints (e.g., helicopter), or 30 min when the activity involves 
aircraft that are not typically fuel constrained.
    (D) After completion of the activity (e.g., prior to maneuvering 
off station), when practical (e.g., when platforms are not constrained 
by fuel restrictions or mission-essential follow-on commitments), Navy 
personnel must observe for marine mammals in the vicinity of where 
detonations occurred; if any injured or dead marine mammals are 
observed, Navy personnel must follow established incident reporting 
procedures. If additional platforms are supporting this activity (e.g., 
providing range clearance), these Navy assets must assist in the visual 
observation of the area where detonations occurred.
    (7) Explosive torpedoes--(i) Number of Lookouts and observation 
platform. One Lookout positioned in an aircraft. If additional 
platforms are participating in the activity, Navy personnel positioned 
in those assets (e.g., safety observers, evaluators) must support 
observing the mitigation zone for applicable biological resources while 
performing their regular duties.
    (ii) Mitigation zone and requirements. 2,100 yd around the intended 
impact location.
    (A) Prior to the initial start of the activity (e.g., during 
deployment of the target), Navy personnel must observe the mitigation 
zone for floating vegetation; if floating vegetation is observed, Navy 
personnel must relocate or delay the start of firing until the 
mitigation zone is clear. Navy personnel must conduct passive acoustic 
monitoring for marine mammals and use the information from detections 
to assist visual observations. Navy personnel must visually observe the 
mitigation zone for marine mammals and jellyfish aggregations; if 
marine mammals or jellyfish aggregations are observed, Navy personnel 
must relocate or delay the start of firing.
    (B) During the activity, Navy personnel must observe for marine 
mammals and jellyfish aggregations; if marine mammals or jellyfish 
aggregation are observed, Navy personnel must cease firing.
    (C) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity, Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing firing) until one of the following conditions has 
been met: the animal is observed exiting the mitigation zone; the 
animal is thought to have exited the mitigation zone based on a 
determination of its course, speed, and movement relative to the 
intended impact location; or the mitigation zone has been clear from 
any additional sightings for 10 min when the activity involves aircraft 
that have fuel constraints, or 30 min when the activity involves 
aircraft that are not typically fuel constrained.
    (D) After completion of the activity (e.g., prior to maneuvering 
off station), Navy personnel must when practical (e.g., when platforms 
are not constrained by fuel restrictions or mission-essential follow-on 
commitments), observe for marine mammals in the vicinity of where 
detonations occurred; if any injured or dead marine mammals are 
observed, Navy personnel must follow established incident reporting 
procedures. If additional platforms are supporting this activity (e.g., 
providing range clearance), these Navy assets must assist in the visual 
observation of the area where detonations occurred.
    (8) Explosive medium-caliber and large-caliber projectiles. Gunnery 
activities using explosive medium-caliber and large-caliber 
projectiles. Mitigation applies to activities using a surface target.
    (i) Number of Lookouts and observation platform. One Lookout must 
be on the vessel or aircraft conducting the activity. For activities 
using explosive large-caliber projectiles, depending on the activity, 
the Lookout could be the same as the one described in ``Weapons firing 
noise'' in paragraph (a)(5)(i) of this section. If additional platforms 
are participating in the activity, Navy personnel positioned in those 
assets (e.g., safety observers, evaluators) must support observing the 
mitigation zone for applicable biological resources while performing 
their regular duties.
    (ii) Mitigation zone and requirements. (A) 200 yd around the 
intended impact location for air-to-surface activities using explosive 
medium-caliber projectiles.
    (B) 600 yd around the intended impact location for surface-to-
surface activities using explosive medium-caliber projectiles.
    (C) 1,000 yd around the intended impact location for surface-to-
surface activities using explosive large-caliber projectiles.
    (D) Prior to the start of the activity (e.g., when maneuvering on 
station), Navy personnel must observe the mitigation zone for floating 
vegetation; if floating vegetation is observed, Navy personnel must 
relocate or delay the start of firing until the mitigation zone is 
clear. Navy personnel must observe the mitigation zone for marine 
mammals; if marine mammals are observed, Navy personnel must relocate 
or delay the start of firing.
    (E) During the activity, Navy personnel must observe for marine 
mammals; if marine mammals are observed, Navy personnel must cease 
firing.
    (F) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity, Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing firing) until one of the following conditions has 
been met: The animal is observed exiting the mitigation zone; the 
animal is thought to have exited the mitigation zone based on a 
determination of its course, speed, and movement relative to the 
intended impact location; the mitigation zone has been clear from any 
additional sightings for 10 min for aircraft-based firing or 30 min for 
vessel-based firing; or for activities using mobile targets, the 
intended impact location has transited a distance equal to double that 
of the mitigation zone size beyond the location of the last sighting.
    (G) After completion of the activity (e.g., prior to maneuvering 
off station), Navy personnel must, when practical (e.g., when platforms 
are not constrained by fuel restrictions or mission-essential follow-on 
commitments), observe for marine mammals in the vicinity of where 
detonations occurred; if any injured or dead marine mammals are 
observed, Navy personnel must follow established incident reporting 
procedures. If additional platforms are supporting this

[[Page 67024]]

activity (e.g., providing range clearance), these Navy assets must 
assist in the visual observation of the area where detonations 
occurred.
    (9) Explosive missiles and rockets. Aircraft-deployed explosive 
missiles and rockets. Mitigation applies to activities using a surface 
target.
    (i) Number of Lookouts and observation platform. One Lookout must 
be positioned in an aircraft. If additional platforms are participating 
in the activity, Navy personnel positioned in those assets (e.g., 
safety observers, evaluators) must support observing the mitigation 
zone for applicable biological resources while performing their regular 
duties.
    (ii) Mitigation zone and requirements. (A) 900 yd around the 
intended impact location for missiles or rockets with 0.6-20 lb net 
explosive weight.
    (B) 2,000 yd around the intended impact location for missiles with 
21-500 lb net explosive weight.
    (C) Prior to the initial start of the activity (e.g., during a fly-
over of the mitigation zone), Navy personnel must observe the 
mitigation zone for floating vegetation; if floating vegetation is 
observed, Navy personnel must relocate or delay the start of firing 
until the mitigation zone is clear. Navy personnel must observe the 
mitigation zone for marine mammals; if marine mammals are observed, 
Navy personnel must relocate or delay the start of firing.
    (D) During the activity, Navy personnel must observe for marine 
mammals; if marine mammals are observed, Navy personnel must cease 
firing.
    (E) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing firing) until one of the following conditions has 
been met: The animal is observed exiting the mitigation zone; the 
animal is thought to have exited the mitigation zone based on a 
determination of its course, speed, and movement relative to the 
intended impact location; or the mitigation zone has been clear from 
any additional sightings for 10 min when the activity involves aircraft 
that have fuel constraints, or 30 min when the activity involves 
aircraft that are not typically fuel constrained.
    (F) After completion of the activity (e.g., prior to maneuvering 
off station), Navy personnel must, when practical (e.g., when platforms 
are not constrained by fuel restrictions or mission-essential follow-on 
commitments), observe for marine mammals in the vicinity of where 
detonations occurred; if any injured or dead marine mammals are 
observed, Navy personnel must follow established incident reporting 
procedures. If additional platforms are supporting this activity (e.g., 
providing range clearance), these Navy assets will assist in the visual 
observation of the area where detonations occurred.
    (10) Explosive bombs--(i) Number of Lookouts and observation 
platform. One Lookout must be positioned in an aircraft conducting the 
activity. If additional platforms are participating in the activity, 
Navy personnel positioned in those assets (e.g., safety observers, 
evaluators) must support observing the mitigation zone for applicable 
biological resources while performing their regular duties.
    (ii) Mitigation zone and requirements. 2,500 yd around the intended 
target.
    (A) Prior to the initial start of the activity (e.g., when arriving 
on station), Navy personnel must observe the mitigation zone for 
floating vegetation; if floating vegetation is observed, Navy personnel 
must relocate or delay the start of bomb deployment until the 
mitigation zone is clear. Navy personnel must observe the mitigation 
zone for marine mammals; if marine mammals are observed, Navy personnel 
must relocate or delay the start of bomb deployment.
    (B) During the activity (e.g., during target approach), Navy 
personnel must observe the mitigation zone for marine mammals; if 
marine mammals are observed, Navy personnel must cease bomb deployment.
    (C) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing bomb deployment) until one of the following 
conditions has been met: The animal is observed exiting the mitigation 
zone; the animal is thought to have exited the mitigation zone based on 
a determination of its course, speed, and movement relative to the 
intended target; the mitigation zone has been clear from any additional 
sightings for 10 min; or for activities using mobile targets, the 
intended target has transited a distance equal to double that of the 
mitigation zone size beyond the location of the last sighting.
    (D) After completion of the activity (e.g., prior to maneuvering 
off station), Navy personnel must, when practical (e.g., when platforms 
are not constrained by fuel restrictions or mission-essential follow-on 
commitments), observe for marine mammals in the vicinity of where 
detonations occurred; if any injured or dead marine mammals are 
observed, Navy personnel must follow established incident reporting 
procedures. If additional platforms are supporting this activity (e.g., 
providing range clearance), these Navy assets must assist in the visual 
observation of the area where detonations occurred.
    (11) Sinking exercises--(i) Number of Lookouts and observation 
platform. Two Lookouts (one must be positioned in an aircraft and one 
must be positioned on a vessel). If additional platforms are 
participating in the activity, Navy personnel positioned in those 
assets (e.g., safety observers, evaluators) must support observing the 
mitigation zone for applicable biological resources while performing 
their regular duties.
    (ii) Mitigation zone and requirements. 2.5 nautical miles (nmi) 
around the target ship hulk.
    (A) Prior to the initial start of the activity (90 min prior to the 
first firing), Navy personnel must conduct aerial observations of the 
mitigation zone for floating vegetation; if floating vegetation is 
observed, Navy personnel must delay the start of firing until the 
mitigation zone is clear. Navy personnel also must conduct aerial 
observations of the mitigation zone for marine mammals and jellyfish 
aggregations; if marine mammals or jellyfish aggregations are observed, 
Navy personnel must delay the start of firing.
    (B) During the activity, Navy personnel must conduct passive 
acoustic monitoring for marine mammals and use the information from 
detections to assist visual observations. Navy personnel must visually 
observe the mitigation zone for marine mammals from the vessel; if 
marine mammals are observed, Navy personnel must cease firing. 
Immediately after any planned or unplanned breaks in weapons firing of 
longer than two hours, Navy personnel must observe the mitigation zone 
for marine mammals from the aircraft and vessel; if marine mammals are 
observed, Navy personnel must delay recommencement of firing.
    (C) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing firing) until one of the following

[[Page 67025]]

conditions has been met: The animal is observed exiting the mitigation 
zone; the animal is thought to have exited the mitigation zone based on 
a determination of its course, speed, and movement relative to the 
target ship hulk; or the mitigation zone has been clear from any 
additional sightings for 30 min.
    (D) After completion of the activity (for two hours after sinking 
the vessel or until sunset, whichever comes first), Navy personnel must 
observe for marine mammals in the vicinity of where detonations 
occurred; if any injured or dead marine mammals are observed, Navy 
personnel must follow established incident reporting procedures. If 
additional platforms are supporting this activity (e.g., providing 
range clearance), these Navy assets will assist in the visual 
observation of the area where detonations occurred.
    (12) Explosive mine countermeasure and neutralization activities--
(i) Number of Lookouts and observation platform. (A) One Lookout must 
be positioned on a vessel or in an aircraft when implementing the 
smaller mitigation zone.
    (B) Two Lookouts (one must be positioned in an aircraft and one 
must be on a small boat) when implementing the larger mitigation zone.
    (C) If additional platforms are participating in the activity, Navy 
personnel positioned in those assets (e.g., safety observers, 
evaluators) must support observing the mitigation zone for applicable 
biological resources while performing their regular duties.
    (ii) Mitigation zone and requirements. (A) 600 yd around the 
detonation site for activities using 0.1-5 lb net explosive weight.
    (B) 2,100 yd around the detonation site for activities using 6-650 
lb net explosive weight (including high explosive target mines).
    (C) Prior to the initial start of the activity (e.g., when 
maneuvering on station; typically, 10 min when the activity involves 
aircraft that have fuel constraints, or 30 min when the activity 
involves aircraft that are not typically fuel constrained), Navy 
personnel must observe the mitigation zone for floating vegetation; if 
floating vegetation is observed, Navy personnel must relocate or delay 
the start of detonations until the mitigation zone is clear. Navy 
personnel must observe the mitigation zone for marine mammals; if 
marine mammals are observed, Navy personnel must relocate or delay the 
start of detonations.
    (D) During the activity, Navy personnel must observe the mitigation 
zone for marine mammals, concentrations of seabirds, and individual 
foraging seabirds; if marine mammals, concentrations of seabirds, and 
individual foraging seabirds are observed, Navy personnel must cease 
detonations.
    (E) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity or a sighting of seabird 
concentrations or individual foraging seabirds during the activity. 
Navy personnel must allow a sighted animal to leave the mitigation zone 
prior to the initial start of the activity (by delaying the start) or 
during the activity (by not recommencing detonations) until one of the 
following conditions has been met: The animal is observed exiting the 
mitigation zone; the animal is thought to have exited the mitigation 
zone based on a determination of its course, speed, and movement 
relative to detonation site; or the mitigation zone has been clear from 
any additional sightings for 10 min when the activity involves aircraft 
that have fuel constraints, or 30 min when the activity involves 
aircraft that are not typically fuel constrained.
    (F) After completion of the activity (typically 10 min when the 
activity involves aircraft that have fuel constraints, or 30 min when 
the activity involves aircraft that are not typically fuel 
constrained), Navy personnel must observe for marine mammals in the 
vicinity of where detonations occurred; if any injured or dead marine 
mammals are observed, Navy personnel must follow established incident 
reporting procedures. If additional platforms are supporting this 
activity (e.g., providing range clearance), these Navy assets must 
assist in the visual observation of the area where detonations 
occurred.
    (13) Explosive mine neutralization activities involving Navy 
divers--(i) Number of Lookouts and observation platform. (A) Two 
Lookouts (two small boats with one Lookout each, or one Lookout must be 
on a small boat and one must be in a rotary-wing aircraft) when 
implementing the smaller mitigation zone.
    (B) Four Lookouts (two small boats with two Lookouts each), and a 
pilot or member of an aircrew must serve as an additional Lookout if 
aircraft are used during the activity, when implementing the larger 
mitigation zone.
    (C) All divers placing the charges on mines will support the 
Lookouts while performing their regular duties and will report 
applicable sightings to their supporting small boat or Range Safety 
Officer.
    (D) If additional platforms are participating in the activity, Navy 
personnel positioned in those assets (e.g., safety observers, 
evaluators) must support observing the mitigation zone for applicable 
biological resources while performing their regular duties.
    (ii) Mitigation zone and requirements. (A) 500 yd around the 
detonation site during activities under positive control using 0.1-20 
lb net explosive weight.
    (B) 1,000 yd around the detonation site during all activities using 
time-delay fuses (0.1-29 lb net explosive weight) and during activities 
under positive control using 21-60 lb net explosive weight charges.
    (C) Prior to the initial start of the activity (e.g., when 
maneuvering on station for activities under positive control; 30 min 
for activities using time-delay firing devices), Navy personnel must 
observe the mitigation zone for floating vegetation; if floating 
vegetation is observed, Navy personnel must relocate or delay the start 
of detonations or fuse initiation until the mitigation zone is clear. 
Navy personnel also must observe the mitigation zone for marine 
mammals; if marine mammals are observed, Navy personnel must relocate 
or delay the start of detonations or fuse initiation.
    (D) During the activity, Navy personnel must observe the mitigation 
zone for marine mammals, concentrations of seabirds, and individual 
foraging seabirds (in the water and not on shore); if marine mammals, 
concentrations of seabirds, and individual foraging seabirds are 
observed, Navy personnel must cease detonations or fuse initiation. To 
the maximum extent practicable depending on mission requirements, 
safety, and environmental conditions, Navy personnel must position 
boats near the mid-point of the mitigation zone radius (but outside of 
the detonation plume and human safety zone), must position themselves 
on opposite sides of the detonation location (when two boats are used), 
and must travel in a circular pattern around the detonation location 
with one Lookout observing inward toward the detonation site and the 
other observing outward toward the perimeter of the mitigation zone. If 
used, Navy aircraft must travel in a circular pattern around the 
detonation location to the maximum extent practicable. Navy personnel 
must not set time-delay firing devices (0.1-29 lb. net explosive 
weight) to exceed 10 min.
    (E) During activities conducted in shallow water, a shore-based 
Navy observer must survey the mitigation zone with binoculars for birds 
before and after each detonation. If training involves multiple 
detonations, the second (or third, etc.) detonation will occur either 
immediately after the

[[Page 67026]]

preceding detonation (i.e., within 10 seconds) or after 30 min to avoid 
potential impacts on birds foraging underwater.
    (F) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity or a sighting of seabird 
concentrations or individual foraging seabirds during the activity. 
Navy personnel must allow a sighted animal to leave the mitigation zone 
prior to the initial start of the activity (by delaying the start) or 
during the activity (by not recommencing detonations) until one of the 
following conditions has been met: the animal is observed exiting the 
mitigation zone; the animal is thought to have exited the mitigation 
zone based on a determination of its course, speed, and movement 
relative to the detonation site; or the mitigation zone has been clear 
from any additional sightings for 10 min during activities under 
positive control with aircraft that have fuel constraints, or 30 min 
during activities under positive control with aircraft that are not 
typically fuel constrained and during activities using time-delay 
firing devices.
    (G) After completion of an activity (for 30 min), the Navy must 
observe for marine mammals for 30 min. Navy personnel must observe for 
marine mammals in the vicinity of where detonations occurred; if any 
injured or dead marine mammals are observed, Navy personnel must follow 
established incident reporting procedures. If additional platforms are 
supporting this activity (e.g., providing range clearance), these Navy 
assets must assist in the visual observation of the area where 
detonations occurred.
    (14) Maritime security operations--anti-swimmer grenades--(i) 
Number of Lookouts and observation platform. One Lookout must be 
positioned on the small boat conducting the activity. If additional 
platforms are participating in the activity, Navy personnel positioned 
in those assets (e.g., safety observers, evaluators) must support 
observing the mitigation zone for applicable biological resources while 
performing their regular duties.
    (ii) Mitigation zone and requirements. 200 yd around the intended 
detonation location.
    (A) Prior to the initial start of the activity (e.g., when 
maneuvering on station), Navy personnel must observe the mitigation 
zone for floating vegetation; if floating vegetation is observed, Navy 
personnel must relocate or delay the start of detonations until the 
mitigation zone is clear. Navy personnel must observe the mitigation 
zone for marine mammals; if marine mammals are observed, Navy personnel 
must relocate or delay the start of detonations.
    (B) During the activity, Navy personnel must observe the mitigation 
zone for marine mammals; if marine mammals are observed, Navy personnel 
must cease detonations.
    (C) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing detonations) until one of the following conditions 
has been met: the animal is observed exiting the mitigation zone; the 
animal is thought to have exited the mitigation zone based on a 
determination of its course, speed, and movement relative to the 
intended detonation location; the mitigation zone has been clear from 
any additional sightings for 30 min; or the intended detonation 
location has transited a distance equal to double that of the 
mitigation zone size beyond the location of the last sighting.
    (D) After completion of the activity (e.g., prior to maneuvering 
off station), Navy personnel must, when practical (e.g., when platforms 
are not constrained by fuel restrictions or mission-essential follow-on 
commitments), observe for marine mammals in the vicinity of where 
detonations occurred; if any injured or dead marine mammals are 
observed, Navy personnel must follow established incident reporting 
procedures. If additional platforms are supporting this activity (e.g., 
providing range clearance), these Navy assets will assist in the visual 
observation of the area where detonations occurred.
    (15) Underwater demolition multiple charge--mat weave and obstacle 
loading exercises--(i) Number of Lookouts and observation platform. Two 
Lookouts (one must be positioned on a small boat and one must be 
positioned on shore from an elevated platform). If additional platforms 
are participating in the activity, Navy personnel positioned in those 
assets (e.g., safety observers, evaluators) must support observing the 
mitigation zone for applicable biological resources while performing 
their regular duties.
    (ii) Mitigation zone and requirements. 700 yd around the intended 
detonation location.
    (A) Prior to the initial start of the activity, or 30 min prior to 
the first detonation, the Lookout positioned on a small boat must 
observe the mitigation zone for floating vegetation and marine mammals; 
if floating vegetation or marine mammals are observed, Navy personnel 
must delay the start of detonations. For 10 min prior to the first 
detonation, the Lookout positioned on shore must use binoculars to 
observe the mitigation zone for marine mammals; if marine mammals are 
observed, Navy personnel must delay the start of detonations until the 
mitigation zone has been clear of any additional sightings for a 
minimum of 10 min.
    (B) During the activity, Navy personnel must observe the mitigation 
zone for marine mammals; if marine mammals are observed, Navy personnel 
must cease detonations.
    (C) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing detonations) until one of the following conditions 
has been met: the animal is observed exiting the mitigation zone; the 
animal is thought to have exited the mitigation zone based on a 
determination of its course, speed, and movement relative to the 
detonation location; or the mitigation zone has been clear from any 
additional sightings for 10 min (as determined by the Navy shore 
observer).
    (D) After completion of the activity (for 30 min), the Lookout 
positioned on a small boat must observe for marine mammals in the 
vicinity of where detonations occurred; if any injured or dead marine 
mammals are observed, Navy personnel must follow established incident 
reporting procedures. If additional platforms are supporting this 
activity (e.g., providing range clearance), these Navy assets must 
assist in the visual observation of the area where detonations 
occurred.
    (16) Vessel movement. The mitigation will not be applied if: the 
vessel's safety is threatened; the vessel is restricted in its ability 
to maneuver (e.g., during launching and recovery of aircraft or landing 
craft, during towing activities, when mooring); the vessel is operated 
autonomously; or when impracticable based on mission requirements 
(e.g., during Amphibious Assault--Battalion Landing exercise).
    (i) Number of Lookouts and observation platform. One Lookout must 
be on the vessel that is underway.
    (ii) Mitigation zone and requirements. (A) 500 yd around whales.
    (B) 200 yd around all other marine mammals (except bow-riding 
dolphins and pinnipeds hauled out on man-made

[[Page 67027]]

navigational structures, port structures, and vessels).
    (iii) During the activity. When underway Navy personnel must 
observe the mitigation zone for marine mammals; if marine mammals are 
observed, Navy personnel must maneuver to maintain distance.
    (iv) Incident reporting procedures. Additionally, if a marine 
mammal vessel strike occurs, Navy personnel must follow the established 
incident reporting procedures.
    (17) Towed in-water devices. Mitigation applies to devices that are 
towed from a manned surface platform or manned aircraft. The mitigation 
will not be applied if the safety of the towing platform or in-water 
device is threatened.
    (i) Number of Lookouts and observation platform. One Lookout must 
be positioned on a manned towing platform.
    (ii) Mitigation zone and requirements. 250 yd around marine 
mammals.
    (iii) During the activity. During the activity (i.e., when towing 
an in-water device), Navy personnel must observe the mitigation zone 
for marine mammals; if marine mammals are observed, Navy personnel must 
maneuver to maintain distance.
    (18) Small-, medium-, and large-caliber non-explosive practice 
munitions. Mitigation applies to activities using a surface target.
    (i) Number of Lookouts and observation platform. One Lookout must 
be positioned on the platform conducting the activity. Depending on the 
activity, the Lookout could be the same as the one described for 
``Weapons firing noise'' in paragraph (a)(5)(i) of this section.
    (ii) Mitigation zone and requirements. 200 yd around the intended 
impact location.
    (A) Prior to the start of the activity (e.g., when maneuvering on 
station), Navy personnel must observe the mitigation zone for floating 
vegetation; if floating vegetation is observed, Navy personnel must 
relocate or delay the start of firing until the mitigation zone is 
clear. Navy personnel must observe the mitigation zone for marine 
mammals; if marine mammals are observed, Navy personnel must relocate 
or delay the start of firing.
    (B) During the activity, Navy personnel must observe the mitigation 
zone for marine mammals; if marine mammals are observed, Navy personnel 
must cease firing.
    (C) Commencement/recommencement conditions after a marine mammal 
sighting before or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing firing) until one of the following conditions has 
been met: the animal is observed exiting the mitigation zone; the 
animal is thought to have exited the mitigation zone based on a 
determination of its course, speed, and movement relative to the 
intended impact location; the mitigation zone has been clear from any 
additional sightings for 10 min for aircraft-based firing or 30 min for 
vessel-based firing; or for activities using a mobile target, the 
intended impact location has transited a distance equal to double that 
of the mitigation zone size beyond the location of the last sighting.
    (19) Non-explosive missiles and rockets. Aircraft-deployed non-
explosive missiles and rockets. Mitigation applies to activities using 
a surface target.
    (i) Number of Lookouts and observation platform. One Lookout must 
be positioned in an aircraft.
    (ii) Mitigation zone and requirements. 900 yd around the intended 
impact location.
    (A) Prior to the initial start of the activity (e.g., during a fly-
over of the mitigation zone), Navy personnel must observe the 
mitigation zone for floating vegetation; if floating vegetation is 
observed, Navy personnel must relocate or delay the start of firing 
until the mitigation zone is clear. Navy personnel must observe the 
mitigation zone for marine mammals; if marine mammals are observed, 
Navy personnel must relocate or delay the start of firing.
    (B) During the activity, Navy personnel must observe the mitigation 
zone for marine mammals; if marine mammals are observed, Navy personnel 
must cease firing.
    (C) Commencement/recommencement conditions after a marine mammal 
sighting prior to or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing firing) until one of the following conditions has 
been met: the animal is observed exiting the mitigation zone; the 
animal is thought to have exited the mitigation zone based on a 
determination of its course, speed, and movement relative to the 
intended impact location; or the mitigation zone has been clear from 
any additional sightings for 10 min when the activity involves aircraft 
that have fuel constraints, or 30 min when the activity involves 
aircraft that are not typically fuel constrained.
    (20) Non-explosive bombs and mine shapes. Non-explosive bombs and 
non-explosive mine shapes during mine laying activities.
    (i) Number of Lookouts and observation platform. One Lookout must 
be positioned in an aircraft.
    (ii) Mitigation zone and requirements. 1,000 yd around the intended 
target.
    (A) Prior to the initial start of the activity (e.g., when arriving 
on station), Navy personnel must observe the mitigation zone for 
floating vegetation; if floating vegetation is observed, Navy personnel 
must relocate or delay the start of bomb deployment or mine laying 
until the mitigation zone is clear. Navy personnel also must observe 
the mitigation zone for marine mammals; if marine mammals are observed, 
Navy personnel must relocate or delay the start of bomb deployment or 
mine laying.
    (B) During the activity (e.g., during approach of the target or 
intended minefield location), Navy personnel must observe the 
mitigation zone for marine mammals and, if marine mammals are observed, 
Navy personnel must cease bomb deployment or mine laying.
    (C) Commencement/recommencement conditions after a marine mammal 
sighting prior to or during the activity. Navy personnel must allow a 
sighted marine mammal to leave the mitigation zone prior to the initial 
start of the activity (by delaying the start) or during the activity 
(by not recommencing bomb deployment or mine laying) until one of the 
following conditions has been met: the animal is observed exiting the 
mitigation zone; the animal is thought to have exited the mitigation 
zone based on a determination of its course, speed, and movement 
relative to the intended target or minefield location; the mitigation 
zone has been clear from any additional sightings for 10 min; or for 
activities using mobile targets, the intended target has transited a 
distance equal to double that of the mitigation zone size beyond the 
location of the last sighting.
    (b) Mitigation areas. In addition to procedural mitigation, Navy 
personnel must implement mitigation measures within mitigation areas to 
avoid or reduce potential impacts on marine mammals.
    (1) Mitigation areas for marine mammals in the Hawaii Range Complex 
for sonar, explosives, and vessel strikes--(i) Mitigation area 
requirements--(A) Hawaii Island Mitigation Area (year-round). (1) 
Except as provided in paragraph (b)(1)(i)(A)(2)

[[Page 67028]]

of this section, Navy personnel must not conduct more than 300 hours of 
MF1 surface ship hull-mounted mid-frequency active sonar or 20 hours of 
MF4 dipping sonar annually, or use explosives that could potentially 
result in takes of marine mammals during training and testing.
    (2) Should national security require conduct of more than 300 hours 
of MF1 surface ship hull-mounted mid-frequency active sonar or 20 hours 
of MF4 dipping sonar, or use of explosives that could potentially 
result in the take of marine mammals during training or testing, Naval 
units must obtain permission from the appropriate designated Command 
authority prior to commencement of the activity. Navy personnel must 
provide NMFS with advance notification and include the information 
(e.g., sonar hours or explosives usage) in its annual activity reports 
submitted to NMFS.
    (B) 4-Islands Region Mitigation Area (November 15-April 15 for 
active sonar; year-round for explosives). (1) Except as provided in 
paragraph (b)(1)(i)(B)(2) of this section, Navy personnel must not use 
MF1 surface ship hull-mounted mid-frequency active sonar or explosives 
that could potentially result in takes of marine mammals during 
training and testing.
    (2) Should national security require use of MF1 surface ship hull-
mounted mid-frequency active sonar or explosives that could potentially 
result in the take of marine mammals during training or testing, Naval 
units must obtain permission from the appropriate designated Command 
authority prior to commencement of the activity. Navy personnel must 
provide NMFS with advance notification and include the information 
(e.g., sonar hours or explosives usage) in its annual activity reports 
submitted to NMFS.
    (C) Humpback Whale Special Reporting Areas (December 15-April 15). 
Navy personnel must report the total hours of surface ship hull-mounted 
mid-frequency active sonar used in the special reporting areas in its 
annual training and testing activity reports submitted to NMFS.
    (D) Humpback Whale Awareness Notification Message Area (November-
April). (1) Navy personnel must issue a seasonal awareness notification 
message to alert ships and aircraft operating in the area to the 
possible presence of concentrations of large whales, including humpback 
whales.
    (2) To maintain safety of navigation and to avoid interactions with 
large whales during transits, Navy personnel must instruct vessels to 
remain vigilant to the presence of large whale species (including 
humpback whales), that when concentrated seasonally, may become 
vulnerable to vessel strikes.
    (3) Platforms must use the information from the awareness 
notification message to assist their visual observation of applicable 
mitigation zones during training and testing activities and to aid in 
the implementation of procedural mitigation.
    (ii) [Reserved]
    (2) Mitigation areas for marine mammals in the Southern California 
portion of the study area for sonar, explosives, and vessel strikes--
(i) Mitigation area requirements--(A) San Diego Arc, San Nicolas 
Island, and Santa Monica/Long Beach Mitigation Areas (June 1-October 
31). (1) Except as provided in paragraph (b)(2)(i)(A)(2) of this 
section, Navy personnel must not conduct more than a total of 200 hours 
of MF1 surface ship hull-mounted mid-frequency active sonar in the 
combined areas, excluding normal maintenance and systems checks, during 
training and testing.
    (2) Should national security require conduct of more than 200 hours 
of MF1 surface ship hull-mounted mid-frequency active sonar in the 
combined areas during training and testing (excluding normal 
maintenance and systems checks), Naval units must obtain permission 
from the appropriate designated Command authority prior to commencement 
of the activity. Navy personnel must provide NMFS with advance 
notification and include the information (e.g., sonar hours) in its 
annual activity reports submitted to NMFS.
    (3) Except as provided in paragraph (b)(2)(i)(A)(4) of this 
section, within the San Diego Arc Mitigation Area, Navy personnel must 
not use explosives that could potentially result in the take of marine 
mammals during large-caliber gunnery, torpedo, bombing, and missile 
(including 2.75-inch rockets) activities during training and testing.
    (4) Should national security require use of explosives that could 
potentially result in the take of marine mammals during large-caliber 
gunnery, torpedo, bombing, and missile (including 2.75-inch rockets) 
activities during training or testing within the San Diego Arc 
Mitigation Area, Naval units must obtain permission from the 
appropriate designated Command authority prior to commencement of the 
activity. Navy personnel must provide NMFS with advance notification 
and include the information (e.g., explosives usage) in its annual 
activity reports submitted to NMFS.
    (5) Except as provided in paragraph (b)(2)(i)(A)(6) of this 
section, within the San Nicolas Island Mitigation Area, Navy personnel 
must not use explosives that could potentially result in the take of 
marine mammals during mine warfare, large-caliber gunnery, torpedo, 
bombing, and missile (including 2.75-inch rockets) activities during 
training.
    (6) Should national security require use of explosives that could 
potentially result in the take of marine mammals during mine warfare, 
large-caliber gunnery, torpedo, bombing, and missile (including 2.75-
inch rockets) activities during training in the San Nicolas Island 
Mitigation Area, Naval units must obtain permission from the 
appropriate designated Command authority prior to commencement of the 
activity. Navy personnel must provide NMFS with advance notification 
and include the information (e.g., explosives usage) in its annual 
activity reports submitted to NMFS.
    (7) Except as provided in paragraph (b)(2)(i)(A)(8) of this 
section, within the Santa Monica/Long Beach Mitigation Area, Navy 
personnel must not use explosives that could potentially result in the 
take of marine mammals during mine warfare, large-caliber gunnery, 
torpedo, bombing, and missile (including 2.75-inch rockets) activities 
during training and testing.
    (8) Should national security require use of explosives that could 
potentially result in the take of marine mammals during mine warfare, 
large-caliber gunnery, torpedo, bombing, and missile (including 2.75-
inch rockets) activities during training or testing in the Santa 
Monica/Long Beach Mitigation Area, Naval units must obtain permission 
from the appropriate designated Command authority prior to commencement 
of the activity. Navy personnel must provide NMFS with advance 
notification and include the information (e.g., explosives usage) in 
its annual activity reports submitted to NMFS.
    (B) Santa Barbara Island Mitigation Area (year-round). (1) Except 
as provided in paragraph (b)(2)(i)(B)(2) of this section, Navy 
personnel must not use MF1 surface ship hull-mounted mid-frequency 
active sonar during training or testing, or explosives that could 
potentially result in the take of marine mammals during medium-caliber 
or large-caliber gunnery, torpedo, bombing, and missile (including 
2.75-inch rockets) activities during training.
    (2) Should national security require use of MF1 surface ship hull-
mounted mid-frequency active sonar during training or testing, or 
explosives that

[[Page 67029]]

could potentially result in the take of marine mammals during medium-
caliber or large-caliber gunnery, torpedo, bombing, and missile 
(including 2.75-inch rockets) activities during training, Naval units 
must obtain permission from the appropriate designated Command 
authority prior to commencement of the activity. Navy personnel must 
provide NMFS with advance notification and include the information 
(e.g., sonar hours or explosives usage) in its annual activity reports 
submitted to NMFS.
    (C) Blue Whale (June-October), Gray Whale (November-March), and Fin 
Whale (November-May) Awareness Notification Message Areas. (1) Navy 
personnel must issue a seasonal awareness notification message to alert 
ships and aircraft operating in the area to the possible presence of 
concentrations of large whales, including blue whales, gray whales, and 
fin whales.
    (2) To maintain safety of navigation and to avoid interactions with 
large whales during transits, Navy personnel must instruct vessels to 
remain vigilant to the presence of large whale species, that when 
concentrated seasonally, may become vulnerable to vessel strikes.
    (3) Platforms must use the information from the awareness 
notification messages to assist their visual observation of applicable 
mitigation zones during training and testing activities and to aid in 
the implementation of procedural mitigation.
    (ii) [Reserved]


Sec.  218.75   Requirements for monitoring and reporting.

    (a) Unauthorized take. Navy personnel must notify NMFS immediately 
(or as soon as operational security considerations allow) if the 
specified activity identified in Sec.  218.70 is thought to have 
resulted in the mortality or serious injury of any marine mammals, or 
in any Level A or Level B harassment take of marine mammals not 
identified in this subpart.
    (b) Monitoring and reporting under the LOAs. The Navy must conduct 
all monitoring and reporting required under the LOAs, including abiding 
by the HSTT Study Area monitoring program. Details on program goals, 
objectives, project selection process, and current projects are 
available at www.navymarinespeciesmonitoring.us.
    (c) Notification of injured, live stranded, or dead marine mammals. 
The Navy must consult the Notification and Reporting Plan, which sets 
out notification, reporting, and other requirements when dead, injured, 
or live stranded marine mammals are detected. The Notification and 
Reporting Plan is available at www.fisheries.noaa.gov/national/marine-mammal-protection/incidentaltake-authorizations-military-readinessactivities.
    (d) Annual HSTT Study Area marine species monitoring report. The 
Navy must submit an annual report of the HSTT Study Area monitoring 
describing the implementation and results from the previous calendar 
year. Data collection methods must be standardized across range 
complexes and study areas to allow for comparison in different 
geographic locations. The report must be submitted to the Director, 
Office of Protected Resources, NMFS, either three months after the end 
of the calendar year, or three months after the conclusion of the 
monitoring year, to be determined by the Adaptive Management process. 
This report will describe progress of knowledge made with respect to 
intermediate scientific objectives within the HSTT Study Area 
associated with the Integrated Comprehensive Monitoring Program (ICMP). 
Similar study questions must be treated together so that progress on 
each topic must be summarized across all Navy ranges. The report need 
not include analyses and content that does not provide direct 
assessment of cumulative progress on the monitoring plan study 
questions. As an alternative, the Navy may submit a multi-Range Complex 
annual Monitoring Plan report to fulfill this requirement. Such a 
report will describe progress of knowledge made with respect to 
monitoring study questions across multiple Navy ranges associated with 
the ICMP. Similar study questions must be treated together so that 
progress on each topic can be summarized across multiple Navy ranges. 
The report need not include analyses and content that does not provide 
direct assessment of cumulative progress on the monitoring study 
question. This will continue to allow the Navy to provide a cohesive 
monitoring report covering multiple ranges (as per ICMP goals), rather 
than entirely separate reports for the HSTT, Gulf of Alaska, Mariana 
Islands, and Northwest Study Areas.
    (e) Annual HSTT Study Area training exercise report and testing 
activity report. Each year, the Navy must submit two preliminary 
reports (Quick Look Report) detailing the status of authorized sound 
sources within 21 days after the anniversary of the date of issuance of 
each LOA to the Director, Office of Protected Resources, NMFS. Each 
year, the Navy must submit detailed reports to the Director, Office of 
Protected Resources, NMFS, within 3 months after the one-year 
anniversary of the date of issuance of the LOA. The HSTT annual 
Training Exercise Report and Testing Activity Report can be 
consolidated with other exercise reports from other range complexes in 
the Pacific Ocean for a single Pacific Exercise Report, if desired. The 
annual reports must contain information on major training exercises 
(MTEs), Sinking Exercise (SINKEX) events, and a summary of all sound 
sources used, including within specific mitigation reporting areas as 
described in paragraph (e)(3) of this section. The analysis in the 
detailed reports must be based on the accumulation of data from the 
current year's report and data collected from previous reports. The 
detailed reports must contain information identified in paragraphs 
(e)(1) through (7) of this section.
    (1) MTEs. This section of the report must contain the following 
information for MTEs conducted in the HSTT Study Area.
    (i) Exercise Information (for each MTE).
    (A) Exercise designator.
    (B) Date that exercise began and ended.
    (C) Location.
    (D) Number and types of active sonar sources used in the exercise.
    (E) Number and types of passive acoustic sources used in exercise.
    (F) Number and types of vessels, aircraft, and other platforms 
participating in exercise.
    (G) Total hours of all active sonar source operation.
    (H) Total hours of each active sonar source bin.
    (I) Wave height (high, low, and average) during exercise.
    (ii) Individual marine mammal sighting information for each 
sighting in each exercise when mitigation occurred:
    (A) Date/Time/Location of sighting.
    (B) Species (if not possible, indication of whale/dolphin/
pinniped).
    (C) Number of individuals.
    (D) Initial Detection Sensor (e.g., sonar, Lookout).
    (E) Indication of specific type of platform observation was made 
from (including, for example, what type of surface vessel or testing 
platform).
    (F) Length of time observers maintained visual contact with marine 
mammal.
    (G) Sea state.
    (H) Visibility.
    (I) Sound source in use at the time of sighting.
    (J) Indication of whether animal was less than 200 yd, 200 to 500 
yd, 500 to 1,000 yd, 1,000 to 2,000 yd, or greater than 2,000 yd from 
sonar source.

[[Page 67030]]

    (K) Whether operation of sonar sensor was delayed, or sonar was 
powered or shut down, and how long the delay.
    (L) If source in use was hull-mounted, true bearing of animal from 
the vessel, true direction of vessel's travel, and estimation of 
animal's motion relative to vessel (opening, closing, parallel).
    (M) Lookouts must report, in plain language and without trying to 
categorize in any way, the observed behavior of the animal(s) (such as 
animal closing to bow ride, paralleling course/speed, floating on 
surface and not swimming, etc.) and if any calves were present.
    (iii) An evaluation (based on data gathered during all of the MTEs) 
of the effectiveness of mitigation measures designed to minimize the 
received level to which marine mammals may be exposed. This evaluation 
must identify the specific observations that support any conclusions 
the Navy reaches about the effectiveness of the mitigation.
    (2) SINKEXs. This section of the report must include the following 
information for each SINKEX completed that year.
    (i) Exercise information (gathered for each SINKEX).
    (A) Location.
    (B) Date and time exercise began and ended.
    (C) Total hours of observation by Lookouts before, during, and 
after exercise.
    (D) Total number and types of explosive source bins detonated.
    (E) Number and types of passive acoustic sources used in exercise.
    (F) Total hours of passive acoustic search time.
    (G) Number and types of vessels, aircraft, and other platforms, 
participating in exercise.
    (H) Wave height in feet (high, low, and average) during exercise.
    (I) Narrative description of sensors and platforms utilized for 
marine mammal detection and timeline illustrating how marine mammal 
detection was conducted.
    (ii) Individual marine mammal observation (by Navy Lookouts) 
information (gathered for each marine mammal sighting) for each 
sighting where mitigation was implemented.
    (A) Date/Time/Location of sighting.
    (B) Species (if not possible, indicate whale, dolphin, or 
pinniped).
    (C) Number of individuals.
    (D) Initial detection sensor (e.g., sonar or Lookout).
    (E) Length of time observers maintained visual contact with marine 
mammal.
    (F) Sea state.
    (G) Visibility.
    (H) Whether sighting was before, during, or after detonations/
exercise, and how many minutes before or after.
    (I) Distance of marine mammal from actual detonations (or target 
spot if not yet detonated): Less than 200 yd, 200 to 500 yd, 500 to 
1,000 yd, 1,000 to 2,000 yd, or greater than 2,000 yd.
    (J) Lookouts must report, in plain language and without trying to 
categorize in any way, the observed behavior of the animal(s) (such as 
animal closing to bow ride, paralleling course/speed, floating on 
surface and not swimming etc.), including speed and direction and if 
any calves were present.
    (K) The report must indicate whether explosive detonations were 
delayed, ceased, modified, or not modified due to marine mammal 
presence and for how long.
    (L) If observation occurred while explosives were detonating in the 
water, indicate munition type in use at time of marine mammal 
detection.
    (3) Summary of sources used. This section of the report must 
include the following information summarized from the authorized sound 
sources used in all training and testing events:
    (i) Total annual hours or quantity (per the LOA) of each bin of 
sonar or other acoustic sources (e.g., pile driving and air gun 
activities); and
    (ii) Total annual expended/detonated ordinance (missiles, bombs, 
sonobuoys, etc.) for each explosive bin.
    (4) Humpback Whale Special Reporting Area (December 15--April 15). 
The Navy must report the total hours of operation of surface ship hull-
mounted mid-frequency active sonar used in the special reporting area.
    (5) HSTT Study Area Mitigation Areas. The Navy must report any use 
that occurred as specifically described in these areas. Information 
included in the classified annual reports may be used to inform future 
adaptive management of activities within the HSTT Study Area.
    (6) Geographic information presentation. The reports must present 
an annual (and seasonal, where practical) depiction of training and 
testing bin usage (as well as pile driving activities) geographically 
across the HSTT Study Area.
    (7) Sonar exercise notification. The Navy must submit to NMFS 
(contact as specified in the LOA) an electronic report within fifteen 
calendar days after the completion of any MTE indicating:
    (i) Location of the exercise;
    (ii) Beginning and end dates of the exercise; and
    (iii) Type of exercise.


Sec.  218.76  Letters of Authorization.

    (a) To incidentally take marine mammals pursuant to the regulations 
in this subpart, the Navy must apply for and obtain LOAs in accordance 
with Sec.  216.106 of this chapter.
    (b) LOAs, unless suspended or revoked, may be effective for a 
period of time not to exceed December 20, 2023.
    (c) If an LOA expires prior to December 20, 2023, the Navy may 
apply for and obtain a renewal of the LOA.
    (d) In the event of projected changes to the activity or to 
mitigation, monitoring, or reporting (excluding changes made pursuant 
to the adaptive management provision of Sec.  218.77(c)(1)) required by 
an LOA issued under this subpart, the Navy must apply for and obtain a 
modification of the LOA as described in Sec.  218.77.
    (e) Each LOA must set forth:
    (1) Permissible methods of incidental taking;
    (2) Geographic areas for incidental taking;
    (3) Means of effecting the least practicable adverse impact (i.e., 
mitigation) on the species or stocks of marine mammals and their 
habitat; and
    (4) Requirements for monitoring and reporting.
    (f) Issuance of the LOA(s) must be based on a determination that 
the level of taking must be consistent with the findings made for the 
total taking allowable under the regulations in this subpart.
    (g) Notice of issuance or denial of the LOA(s) must be published in 
the Federal Register within 30 days of a determination.


Sec.  218.77  Renewals and modifications of Letters of Authorization.

    (a) An LOA issued under Sec. Sec.  216.106 of this chapter and 
218.76 for the activity identified in Sec.  218.70(c) may be renewed or 
modified upon request by the applicant, provided that:
    (1) The planned specified activity and mitigation, monitoring, and 
reporting measures, as well as the anticipated impacts, are the same as 
those described and analyzed for 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

[[Page 67031]]

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. Sec.  216.106 of this chapter and 
218.76 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. Sec.  216.106 
of this chapter and 218.76, 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.


Sec. Sec.  218.78-218.79   [Reserved]

[FR Doc. 2018-27342 Filed 12-20-18; 8:45 am]
 BILLING CODE 3510-22-P