[Federal Register Volume 89, Number 107 (Monday, June 3, 2024)]
[Notices]
[Pages 47539-47555]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-12062]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XD889]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to U.S. Navy Maintenance and Pile 
Replacement Project in Puget Sound, Washington

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

ACTION: Notice; issuance of incidental harassment authorizations.

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SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA) as amended, notification is hereby given 
that NMFS has issued an incidental harassment authorization (IHA) to 
the United States Navy (Navy) to incidentally harass marine mammals 
during construction activities associated with the Naval Facilities 
Engineering Command Northwest (NAVFAC NW) Maintenance and Pile 
Replacement (MPR) project in Puget Sound, Washington.

DATES: These authorizations are effective from July 1, 2024 through 
June 30, 2025 and July 1, 2025 through June 30, 2026.

ADDRESSES: Electronic copies of the application and supporting 
documents, as well as a list of the references cited in this document, 
may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of problems accessing these documents, please call 
the contact listed below.

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

SUPPLEMENTARY INFORMATION: 

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are proposed or, if the taking is limited to harassment, a notice of a 
proposed IHA is provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the monitoring and 
reporting of the takings. The definitions of all applicable MMPA 
statutory terms cited above are included in the relevant sections 
below.

Summary of Request

    On October 5, 2023, NMFS received a request from the Navy for two 
consecutive 1-year IHAs to take marine mammals incidental to 
construction associated with the Navy's NAVFAC NW MPR project in Puget 
Sound, Washington. Following NMFS' review of the application, the Navy 
submitted a revised version on December 14, 2023, additional 
information on January 10, 2024, and the marine mammal monitoring plan 
on January 23, 2024. Final revisions to both the application and the 
marine mammal monitoring plan were provided on March 2, 2024. The 
application was deemed adequate and complete on February 27, 2024. The 
Navy's request is for take of 10 species of marine mammals by Level B 
harassment and, for harbor seal, Level B and Level A harassment. 
Neither the Navy nor NMFS expect serious injury or mortality to result 
from this activity. Therefore, IHAs are appropriate.
    NMFS previously issued a regulation and associated Letters of 
Authorization (LOAs) to the Navy for related work (84 FR 15963, April 
17, 2019); https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-navy-marine-structure-maintenance-and-pile-replacement-wa). The Navy complied with all the requirements (e.g., 
mitigation, monitoring, and reporting) of the previous LOAs, and 
information regarding their monitoring results may be found in the 
Effects of Specified Activities on Marine Mammals and Their Habitat of 
the Federal Register Notice for the proposed IHA. Please refer to the 
notice of proposed IHAs (89 FR 25580, April 11, 2024).
    There are no changes from the Proposed IHAs to the Final IHAs.

Description of the Specified Activity

Overview

    Maintaining existing wharfs and piers is vital to sustaining the 
Navy's mission and ensuring readiness. To ensure continuance of 
necessary missions at the four installations, the Navy must conduct 
annual maintenance and repair activities at existing marine waterfront 
structures, including removal and replacement of piles of various types 
and sizes. The Navy refers to this program as the Marine Structure MPR 
program.

[[Page 47540]]

    The activities that have the potential to take marine mammals by 
Level A harassment and Level B harassment include installation and/or 
removal of timber, concrete, and steel piles by vibratory and impact 
pile driving and down-the hole (DTH) drilling. Construction will span 
the course of 2 years, with the first year beginning on July 15, 2024, 
and lasting through July 14, 2025. The second year of construction 
activities will begin July 15, 2025, and continue through July 14, 
2026.
    A detailed description of the planned construction project is 
provided in the Federal Register notice for the proposed IHAs (89 FR 
25580, April 11, 2024). Since that time no changes have been made to 
the planned activities. Therefore, a detailed description is not 
provided here. Please refer to that Federal Register notice for the 
description of the specific activity.

Comments and Responses

    A notice of NMFS' proposal to issue an IHA to the Navy was 
published in the Federal Register on April 11, 2024 (89 FR 25580). That 
notice described, in detail, the Navy's activity, the marine mammal 
species that may be affected by the activity, and the anticipated 
effects on marine mammals. In that notice, we requested public input on 
the request for authorization described therein, our analyses, the 
proposed authorization, and any other aspect of the notice of proposed 
IHA, and requested that interested persons submit relevant information, 
suggestions, and comments. During the 30-day public comment period, the 
Bureau of Land Management noted that they ``do not have additional 
comments to submit at this time.'' NMFS received no other public 
comments.

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, instead of reprinting the information. Additional 
information regarding population trends and threats may be found in 
NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and 
more general information about these species (e.g., physical and 
behavioral descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
    Table 1 lists all species or stocks for which take is expected and 
authorized for both IHAs, and summarizes information related to the 
population or stock, including regulatory status under the MMPA and 
Endangered Species Act (ESA) and potential biological removal (PBR), 
where known. PBR is defined by 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 (as described in NMFS' SARs). While no 
serious injury or mortality is anticipated or authorized here, PBR and 
annual serious injury and mortality from anthropogenic sources are 
included here as gross indicators of the status of the species or 
stocks and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Alaska and Pacific SARs. All values presented in table 1 are 
the most recent available at the time of publication (including from 
the draft 2023 SARs) and are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                  Table 1--Marine Mammal Species \4\ Likely To Be Affected by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         ESA/MMPA status;    Stock abundance (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
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                                                 Order Artiodactyla--Cetacea--Mysticeti (baleen whales)
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Family Eschrichtiidae:
    Gray Whale......................  Eschrichtius robustus..  Eastern N Pacific......  -, -, N             26,960 (0.05, 25,849,         801        131
                                                                                                             2016).
Family Balaenopteridae (rorquals)
    Humpback Whale..................  Megaptera novaeangliae.  Central America/         E, D, Y             1,494 (0.171, 1,284,          3.5       14.9
                                                                Southern Mexico--CA/OR/                      2021).
                                                                WA.
                                                               Mainland Mexico--CA/OR/  T, D, Y             3,477 (0.101, 3,185,           43         22
                                                                WA.                                          2018).
                                                               Hawai'i................  -, -, N             11,278 (0.56, 7,265,          127      27.09
                                                                                                             2020).
    Minke Whale.....................  Balaenoptera             CA/OR/WA...............  -, -, N             915 (0.792, 509, 2018)        4.1       0.19
                                       acutorostrata.
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                                                  Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Killer Whale....................  Orcinus orca...........  Eastern North Pacific    E, D, Y             73 (N/A, 73, 2022)....       0.13          0
                                                                Southern Resident.
                                                               West Coast Transient...  -, -, N             349 \5\ (N/A, 349,            3.5        0.4
                                                                                                             2018).
Family Phocoenidae (porpoises):
    Dall's Porpoise.................  Phocoenoides dalli.....  CA/OR/WA...............  -, -, N             16,498 (0.61, 10,286,          99     >=0.66
                                                                                                             2018).
    Harbor Porpoise.................  Phocoena phocoena......  Washington Inland        -, -, N             11,233 (0.37, 8,308,           66      >=7.2
                                                                Waters.                                      2015).
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[[Page 47541]]

 
                                                               Order Carnivora--Pinnipedia
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Family Otariidae (eared seals and
 sea lions):
    CA Sea Lion.....................  Zalophus californianus.  U.S....................  -, -, N             257,606 (N/A, 233,515,     14,011       >321
                                                                                                             2014).
    Steller Sea Lion................  Eumetopias jubatus.....  Eastern................  -, -, N             36,308 \6\ (N/A,            2,178       93.2
                                                                                                             36,308, 2022).
Family Phocidae (earless seals):
    Harbor Seal.....................  Phoca vitulina.........  Washington Inland Hood   -, -, N             3,363 (0.16, 2,940,            88          2
                                                                Canal.                                       2019).
                                                               Washington Northern      -, -, N             16,451 (0.07, 15,462,         928         40
                                                                Inland Waters.                               2019).
    Northern Elephant Seal..........  Mirounga angustirostris  CA Breeding............  -, -, N             187,386 (N/A, 85,369,       5,122       13.7
                                                                                                             2013).
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\1\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
  designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or
  which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is
  automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal SARs online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region.
  CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.
\4\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
  (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/).
\5\ Nest is based upon count of individuals identified from photo-ID catalogs in analysis of a subset of data from 1958-2018.
\6\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the U.S.
  only.

    A detailed description of the species likely to be affected by the 
Navy's NAVFAC NW MPR project, including brief introductions to the 
species and relevant stocks as well as available information regarding 
population trends and threats, and information regarding local 
occurrence, were provided in the Federal Register notice for the 
proposed IHAs (89 FR 25580, April 11, 2024); since that time, we are 
not aware of any changes in the status of these species and stocks; 
therefore, detailed descriptions are not provided here. Please refer to 
that Federal Register notice for these descriptions. Please also refer 
to NMFS' website (https://www.fisheries.noaa.gov/find-species) for 
generalized species accounts.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Not all marine mammal species have equal 
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and 
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al. 
(2007, 2019) recommended that marine mammals be divided into hearing 
groups based on directly measured (behavioral or auditory evoked 
potential techniques) or estimated hearing ranges (behavioral response 
data, anatomical modeling, etc.). Note that no direct measurements of 
hearing ability have been successfully completed for mysticetes (i.e., 
low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in table 2.

                  Table 2--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
          Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans       7 Hz to 35 kHz.
 (baleen whales).
Mid-frequency (MF) cetaceans       150 Hz to 160 kHz.
 (dolphins, toothed whales,
 beaked whales, bottlenose
 whales).
High-frequency (HF) cetaceans      275 Hz to 160 kHz.
 (true porpoises, Kogia, river
 dolphins, Cephalorhynchid,
 Lagenorhynchus cruciger & L.
 australis).
Phocid pinnipeds (PW)              50 Hz to 86 kHz.
 (underwater) (true seals).
Otariid pinnipeds (OW)             60 Hz to 39 kHz.
 (underwater) (sea lions and fur
 seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al., 2007) and PW pinniped (approximation).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al., 
2013).
    For more detail concerning these groups and associated frequency 
ranges,

[[Page 47542]]

please see NMFS (2018) for a review of available information.

Effects of Specified Activities on Marine Mammals and Their Habitat

    The effects of underwater noise from the Navy's construction 
activities have the potential to result in behavioral harassment of 
marine mammals in the vicinity of the project area. The notice of the 
proposed IHAs (89 FR 25580, April 11, 2024) included a discussion of 
the effects of anthropogenic noise on marine mammals and the potential 
effects of underwater noise from the Navy's construction on marine 
mammals and their habitat. That information and analysis is referenced 
in this final IHA determination and is not repeated here; please refer 
to the notice of proposed IHAs (89 FR 25580, April 11, 2024).

Estimated Take

    This section provides an estimate of the number of incidental takes 
authorized through the IHAs, which will inform both NMFS' consideration 
of ``small numbers,'' and the negligible impact determinations.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes will primarily be by Level B harassment, as use of 
the acoustic sources (i.e., impact and vibratory pile driving and 
removal and DTH drilling) has the potential to result in disruption of 
behavioral patterns for individual marine mammals. There is also some 
potential for auditory injury (Level A harassment) to result, primarily 
for phocids because predicted auditory injury zones are larger than for 
mid-frequency cetacean species and/or otariids, and they can be 
difficult to detect. Auditory injury is unlikely to occur for mid, low, 
and high-frequency cetacean species and otariids. The planned 
mitigation and monitoring measures are expected to minimize the 
severity of the taking to the extent practicable.
    As described previously, no serious injury or mortality is 
anticipated or authorized for this activity. Below, we describe how the 
take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) acoustic thresholds above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed or incur some degree of permanent hearing impairment; (2) the 
area or volume of water that will be ensonified above these levels in a 
day; (3) the density or occurrence of marine mammals within these 
ensonified areas; and (4) the number of days of activities. We note 
that while these factors can contribute to a basic calculation to 
provide an initial prediction of potential takes, additional 
information that can qualitatively inform take estimates is also 
sometimes available (e.g., previous monitoring results or average group 
size). Below, we describe the factors considered here in more detail 
and present the take estimates.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur permanent threshold shift (PTS) of some 
degree (equated to Level A harassment).
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007, 2021; Ellison et al., 2012). 
Based on what the available science indicates and the practical need to 
use a threshold based on a metric that is both predictable and 
measurable for most activities, NMFS typically uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS generally predicts that marine mammals are 
likely to be behaviorally harassed in a manner considered to be Level B 
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (c) of 120 dB (re 1 [mu]Pa) for 
continuous (e.g., vibratory pile driving, drilling) and above root mean 
square (RMS) sound pressure level (SPL) 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g., 
scientific sonar) sources. Generally speaking, Level B harassment take 
estimates based on these behavioral harassment thresholds are expected 
to include any likely takes by temporary threshold shift (TTS) as, in 
most cases, the likelihood of TTS occurs at distances from the source 
less than those at which behavioral harassment is likely. TTS of a 
sufficient degree can manifest as behavioral harassment, as reduced 
hearing sensitivity and the potential reduced opportunities to detect 
important signals (conspecific communication, predators, prey) may 
result in changes in behavior patterns that would not otherwise occur.
    The Navy's activity includes the use of continuous (vibratory pile 
driving and removal and DTH drilling) and impulsive (impact pile 
driving and DTH drilling) sources, and therefore the RMS SPL thresholds 
of 120 and 160 dB re 1 [mu]Pa is applicable, respectively.
    Level A harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) 
(Technical Guidance, 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 Navy's 
activity includes the use of impulsive (impact pile driving and DTH 
drilling) and non-impulsive (vibratory pile driving and removal) 
sources.
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

[[Page 47543]]



                     Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                     PTS onset acoustic thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;   Cell 2: LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,MF,24h: 198 dB.
                                          LE,F,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;   Cell 8: LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;   Cell 10: LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and SELcum (LE) has a reference value of
  1[micro]Pa\2\s. In this table, thresholds are abbreviated to reflect American National Standards Institute
  (ANSI) standards (ANSI, 2013). However, peak sound pressure is defined by ANSI as incorporating frequency
  weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is being
  included to indicate peak sound pressure should be flat weighted or unweighted within the generalized hearing
  range. The subscript associated with SELcum thresholds indicates the designated marine mammal auditory
  weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation
  period is 24 hours. The SELcum thresholds could be exceeded in a multitude of ways (i.e., varying exposure
  levels and durations, duty cycle). When possible, it is valuable for action proponents to indicate the
  conditions under which these acoustic thresholds will be exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that are used in estimating the area ensonified above the 
acoustic thresholds, including source levels and transmission loss (TL) 
coefficient.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the project. Marine 
mammals are expected to be affected via sound generated by the primary 
components of the project (i.e., pile driving and removal and DTH 
drilling).
    The project includes vibratory pile installation and removal, 
impact pile driving, and DTH drilling in year 1 and vibratory pile 
installation and removal and impact pile driving in year 2. Source 
levels for these activities are based on reviews of measurements of the 
same or similar types and dimensions of piles available in the 
literature. Source levels for each pile size and activity each year are 
presented in table 4. Source levels for vibratory installation and 
removal of piles of the same diameter are assumed to be the same.
    NMFS recommends treating DTH systems as both impulsive and 
continuous, non-impulsive sound source type simultaneously. Thus, 
impulsive thresholds are used to evaluate Level A harassment, and 
continuous thresholds are used to evaluate Level B harassment. With 
regards to DTH mono-hammers, NMFS recommends proxy levels for Level A 
harassment based on available data regarding DTH systems of similar 
sized piles and holes (Heyvaert and Reyff, 2021) (table 5 and table 6 
includes number of piles and duration each year; table 4 includes sound 
pressure and sound exposure levels for each pile type).
    The Navy plans to use bubble curtains when impact driving steel 
piles (relevant to year 2 activities only). For the reasons described 
in the next paragraph, we assume here that use of the bubble curtain 
would result in a reduction of 8 dB from the assumed SPL (rms) and SPL 
(peak) source levels for these pile sizes, and reduce the applied 
source levels accordingly.
    During the 2023 study at Naval Base Kitsap (NBK) Bremerton, the 
Navy conducted comparative measurements of source levels when impact 
driving steel piles with and without a bubble curtain. Underwater sound 
levels were measured at two locations during the installation of one 
24-in diameter steel pile and four 36-in steel piles. The bubble 
curtain used during the measurements reduced median peak sound levels 
by between 8 and 12 dB, median RMS sound levels by 10 and 12 dB, and 
median single strike SEL sound levels by 7 and 8 dB. The analysis 
included in the proposed rule for the regulations preceding these IHAs 
(83 FR 9366, March 5, 2018) as well as results from the NBK Bangor 
Trident Support Facilities Explosive Handling Wharf study (Navy, 2013), 
are consistent with these findings. While proper set-up and operation 
of the system is critical, and variability in performance should be 
expected, we believe that in the circumstances evaluated here an 
effective attenuation performance of 8 dB is a reasonable assumption.

Table 4--Estimates of Mean Underwater Sound Levels Generated During Vibratory and Impact Pile Installation, DTH Drilling, and Vibratory Pile Removal for
                                                                    Year 1 and Year 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
       Pile driving method             Pile type         Pile size        dB RMS          dB peak         dB SEL        Attenuation        Reference
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         Year 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact..........................  Concrete..........           18-in             170             184             159             N/A  Navy 2015.
                                                               24-in             174             188             164             N/A  Navy 2015.
Vibratory.......................  Timber............           13-in             161             N/A             N/A             N/A  Greenbusch Group,
                                                                                                                                       Inc. 2019.
DTH.............................  Concrete..........           24-in             167             184             159             N/A  Heyvaert & Reyff
                                                                                                                                       2021.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         Year 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact..........................  Steel \1\.........              12             177             192             167       -8 dB \1\  Caltrans 2015,
                                                                                                                                       2020.
                                                                  36             194             211             181       -8 dB \1\  Navy 2015b.
Vibratory.......................  ..................              12             153             N/A             N/A             N/A  Navy 2015b.
                                                                  24             161             N/A             N/A             N/A  Navy 2015b.

[[Page 47544]]

 
                                                                  36             166             N/A             N/A             N/A  Navy 2015b.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; DTH = down-the-hole drilling; rms = root mean square; SEL = sound exposure level.
\1\ Values modeled for impact driving of 12-inch and 36-inch steel piles will be reduced by 8 dB for noise exposure modeling to account for attenuation
  from a bubble curtain.

    TL is the decrease in acoustic intensity as an acoustic pressure 
wave propagates out from a source. TL parameters vary with frequency, 
temperature, sea conditions, current, source and receiver depth, water 
depth, water chemistry, and bottom composition and topography. The 
general formula for underwater TL is:

TL = B * Log10 (R1/R2),

where

TL = transmission loss in dB
B = transmission loss coefficient
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement

    Absent site-specific acoustical monitoring with differing measured 
TL, a practical spreading value of 15 is used as the TL coefficient in 
the above formula. Site-specific TL data for the Puget Sound are not 
available; therefore, the default coefficient of 15 is used to 
determine the distances to the Level A harassment and Level B 
harassment thresholds.
    The ensonified area associated with Level A harassment is more 
technically challenging to predict due to the need to account for a 
duration component. Therefore, NMFS developed an optional User 
Spreadsheet tool to accompany the Technical Guidance that can be used 
to relatively simply predict an isopleth distance for use in 
conjunction with marine mammal density or occurrence to help predict 
potential takes. We note that because of some of the assumptions 
included in the methods underlying this optional tool, we anticipate 
that the resulting isopleth estimates are typically overestimates of 
some degree, which may result in an overestimate of potential take by 
Level A harassment. However, this optional tool offers the best way to 
estimate isopleth distances when more sophisticated modeling methods 
are not available or practical. For stationary sources such as pile 
driving, the optional User Spreadsheet tool predicts the distance at 
which, if a marine mammal remained at that distance for the duration of 
the activity, it would be expected to incur PTS. Inputs used in the 
optional User Spreadsheet tool, and the resulting estimated isopleths, 
are reported below.

                                    Table 5--User Spreadsheet Inputs, Year 1
----------------------------------------------------------------------------------------------------------------
                                       Vibratory                      Impact                          DTH
                                 -------------------------------------------------------------------------------
                                     13-in Timber       18-in Concrete      24-in Concrete      24-in Concrete
                                 -------------------------------------------------------------------------------
                                    Installation or
                                        removal          Installation        Installation        Installation
----------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used............  A.1) Vibratory      E.1) Impact Pile    E.1) Impact Pile    E.2) DTH Drilling.
                                   Pile Driving.       Driving.            Driving.
Source Level (SPL)..............  161 RMS...........  159 SEL...........  164 SEL...........  167 RMS, 159 SEL.
Transmission Loss Coefficient...  15................  15................  15................  15.
Weighting Factor Adjustment       2.5...............  2.................  2.................  2.
 (kHz).
Activity Duration per day         90................  ..................  ..................  80.
 (minutes).
Strike Rate per second..........  ..................  ..................  ..................  12.
Number of strikes per pile......  ..................  1000..............  1000..............  ..................
Number of piles per day.........  6.................  5.................  4.................  2.
Distance of sound pressure level  10................  10................  10................  10.
 measurement.
----------------------------------------------------------------------------------------------------------------


                                                        Table 6--User Spreadsheet Inputs, Year 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Vibratory                                                   Impact
                                    --------------------------------------------------------------------------------------------------------------------
                                           12-in Steel             24-in Steel            36-in Steel          12-in Steel; BC        36-in Steel; BC
                                    --------------------------------------------------------------------------------------------------------------------
                                         Installation or         Installation or        Installation or
                                             removal                 removal                removal              Installation           Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used...............  A.1) Vibratory Pile     A.1) Vibratory Pile     A.1) Vibratory Pile    E.1) Impact Pile       E.1) Impact Pile
                                      Driving.                Driving.                Driving.               Driving.               Driving.
Source Level (SPL).................  153 RMS...............  161 RMS...............  166 RMS..............  167 SEL..............  181 SEL.
Transmission Loss Coefficient......  15....................  15....................  15...................  15...................  15.
Weighting Factor Adjustment (kHz)..  2.5...................  2.5...................  2.5..................  2....................  2.
Activity Duration per day (minutes)  30....................  90....................  133..................  N/A..................  N/A.
Number of strikes per pile.........  N/A...................  N/A...................  N/A..................  1000.................  1000.
Number of piles per day............  2.....................  6.....................  4....................  2....................  4.
Distance of sound pressure level     10....................  10....................  10...................  10...................  10.
 measurement.
--------------------------------------------------------------------------------------------------------------------------------------------------------
BC = Bubble Curtain.


[[Page 47545]]


                  Table 7--Level A Harassment and Level B Harassment Isopleths From Vibratory and Impact Pile Driving and DTH Drilling
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Level A harassment isopleths (m)                             Level B         Area of
                Pile type                --------------------------------------------------------------------------------   harassment      harassment
                                                LF              MF              HF              PW              OW         isopleth (m)    zone (km\2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         Year 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory:
    13-inch timber......................             8.9              <1            13.2             5.4              <1           5,412              16
Impact:
    18-inch concrete....................            73.3             2.6            87.4            39.3             2.9              46           0.007
    24-inch concrete....................           136.2             4.8           162.2            72.9             5.3              86            0.02
DTH:
    24-inch concrete....................           374.1            13.3           445.6           200.2            14.6          13,594              75
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         Year 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory:
    12-inch steel.......................             1.3              <1              <1              <1              <1           1,585               8
    24-inch steel.......................             8.9              <1            13.2             5.4              <1           5,412              16
    36-inch steel.......................            25.1             2.2            37.0            15.2             1.1          11,659              31
Impact:
    12-inch steel.......................            39.8             1.4            47.4            21.3             1.6            39.8           0.005
    36-inch steel.......................           542.1            19.3           645.8           290.1            21.1           541.2            0.92
--------------------------------------------------------------------------------------------------------------------------------------------------------

Marine Mammal Occurrence

    In this section, we provide information about the occurrence of 
marine mammals, including density or other relevant information that 
will inform the take calculations.
    Available information regarding marine mammal occurrence in the 
vicinity of the four installations includes density information 
aggregated in the Navy's Marine Mammal Species Density Database (NMSDD; 
Navy, 2019) or site-specific survey information from particular 
installations (e.g., local pinniped counts). More recent density 
estimates for harbor porpoise are available in Smultea et al. (2017) 
and Rone et al., (2024). First, for each installation we describe 
anticipated frequency of occurrence and the information deemed most 
appropriate for the exposure estimates. For all facilities, large 
whales (humpback whale, minke whale, and gray whale), killer whales 
(transient and resident), Dall's porpoise, and elephant seal are 
considered as occurring only rarely and unpredictably, on the basis of 
past sighting records. For these species, average group size is 
considered in concert with expected frequency of occurrence to develop 
the most realistic exposure estimate. Although certain species are not 
expected to occur at all at some facilities--for example, resident 
killer whales are not expected to occur in Hood Canal--the Navy has 
developed an overall take estimate and request for these species for 
each project year.
    All species described above are considered as rare, unpredictably 
occurring species. A density-based analysis is used for harbor porpoise 
(table 8), while data from site-specific abundance surveys are used for 
California sea lion, Steller sea lion, and harbor seal at all 
installations. One exception is that for Steller sea lion at NBK 
Bremerton, a density-based analysis is used because local data have 
resulted in no observations of this species (Navy, 2023).

                    Table 8--Marine Mammal Densities
------------------------------------------------------------------------
                                                         Density (June-
             Species                     Region            February)
------------------------------------------------------------------------
Harbor porpoise.................  Hood Canal (Bangor)           \1\ 0.81
                                  East Whidbey Island           \2\ 0.75
                                   (Everett).
                                  Sinclair Inlet                \2\ 0.53
                                   (Bremerton).
                                  Vashon (Manchester)           \2\ 0.25
Steller Sea Lion................  Puget Sound--Fall/            \3\ 0.05
                                   Winter.
------------------------------------------------------------------------
Sources: \1\ Rone et al., 2024; \2\ Smultea et al., 2017; \3\ Navy,
  2019.

Take Estimation

    Here, we describe how the information provided above is synthesized 
to produce a quantitative estimate of the take that is reasonably 
likely to occur and authorized.
    To quantitatively assess exposure of marine mammals to noise from 
pile driving activities, the Navy plans three methods, to be used 
depending on the species' assumed spatial and temporal occurrence. For 
species with rare or infrequent occurrence at a given installation 
during the in-water work window, the likelihood of interaction was 
reviewed on the basis of past records of occurrence (described in 
Description of Marine Mammals in the Area of Specified Activities) and 
the potential maximum duration of work days at each installation, as 
well as total work days for all installations. Occurrence of the 
species in this category [i.e., large whales, killer whales, elephant 
seal (all installations), and Dall's porpoise (Hood Canal only)] would 
not be anticipated to extend for multiple days. Except for southern 
resident killer whales (SRKW), the probable duration of all rare, 
unpredictably occurring species is assumed to be 2 days, roughly 
equivalent to one transit in and out of a project site. In the case of 
SRKW, the probable duration is assumed to be 1 day only, as SRKW have 
not been observed near naval installations during work completed 
previously at these

[[Page 47546]]

installations. The calculation for species with rare or infrequent 
occurrence is:

Exposure estimate = expected group size x probable duration

    For species that occur regularly but for which site-specific 
abundance information is not available, density estimates (table 8) 
were used to determine the number of animals potentially exposed on any 
one day of pile driving or removal. The calculation for density-based 
analysis of species with regular occurrence is:

Exposure estimate = N (density) x Zone of Influence (ZOI, area) x days 
of pile driving

    For remaining species, site-specific abundance information (i.e., 
primarily the mean of monthly average counts per surveys completed 
between 2008 and 2022) was used. In cases where documented presence of 
a given pinniped species was variable throughout year and the mean of 
monthly average count (2008-2022) was >=1, the mean of monthly maximum 
counts of surveys completed between 2008 and 2022 was used:

Exposure estimate = Abundance x days of pile driving

    Large Whales--For each species of large whale (i.e., humpback 
whale, minke whale, and gray whale), we assume rare and infrequent 
occurrence at all installations. For all three species, if observed, 
they typically occur singly or in pairs. Therefore, for all three 
species, we assume that a pair of whales may occur in the vicinity of 
an installation for a total of 2 days. We do not expect that this would 
happen multiple times, and cannot predict where such an occurrence may 
happen, so propose to authorize take by Level B harassment of four of 
each large whale species each project year.
    It is important to note that the Navy proposes to implement a 
shutdown of pile driving activity if any large whale is observed within 
any defined harassment zone (see Mitigation). Therefore, the IHAs are 
intended to provide insurance against the event that whales occur 
within Level B harassment zones that cannot be fully observed by 
monitors. As a result of this planned mitigation, we do not believe 
that Level A harassment is a likely outcome upon occurrence of any 
large whale. The calculated Level A harassment zone is a maximum of 374 
m for DTH installation of 24-in concrete piles in year 1 and 542 m for 
impact installation of 36-in steel piles with a bubble curtain in year, 
and this requires that a whale be present at that range for the full 
duration of 1,000 pile strikes. Given the Navy's commitment to shut 
down upon observation of a large whale in any harassment zone, and the 
likelihood that the presence of a large whale in the vicinity of any 
Navy installation would be known due to reporting via Orca Network, we 
do not expect that any whale would be present within a Level A 
harassment zone for sufficient duration to actually experience PTS.
    Killer Whales--For transient killer whales, the take authorization 
is derived via the same process described above for large whales: we 
assume an average group size of six whales occurring for a period of 2 
days. The resulting total authorization of take by Level B harassment 
of 12 for transient killer whales would also account for the low 
probability that a larger group occurred once. For SRKW, we assume an 
average group size of 20 whales occurring within the Level B harassment 
zone on 1 day each year. A group of 20 SRKW closely represents the 
average size of the pod most likely to occur near a Navy installation 
(the J pod), and corresponds to 75 percent of the average of all 3 pods 
that make up the stock. SRKW have not been observed near naval 
installations during work completed previously at these installations.
    Similar to large whales, the Navy plans to implement shutdown of 
pile driving activity at any time that any killer whale is observed 
within any calculated harassment zone. We expect this to minimize the 
extent and duration of any behavioral harassment. Given the small size 
of calculated Level A harassment zones--maximum of 13 m for DTH in year 
1, and 20 m for the worst-case scenario of impact-driven 36-in steel 
piles with a bubble curtain--we do not anticipate any potential for 
Level A harassment of killer whales.
    Dall's Porpoise--We assume rare and infrequent occurrence of Dall's 
porpoise at all installations. If observed, they typically occur in 
groups of five (Smultea et al., 2017). Therefore, we assume that a 
group of Dall's porpoise may occur in the vicinity of an installation 
for a total of 2 days. We do not expect that this would happen multiple 
times, and cannot predict where such an occurrence may happen, so 
conservatively propose to authorize take by Level B harassment of a 
total of 10 Dall's porpoise each project year.
    The Navy plans to implement shutdown of pile driving activity at 
any time if a Dall's porpoise is observed in the Level A harassment 
zone. The calculated Level A harassment zone is as large as 445 m for 
DTH of 24-in concrete in year 1 and as large as 646 m for impact 
driving of 36-in steel piles with a bubble curtain in year 2. Take by 
level A harassment would require that a porpoise be present at that 
range for the full duration of 1,000 pile strikes. Given the rarity of 
Dall's porpoise in the area, the Navy's commitment to shut down upon 
observation of a porpoise within the Level A harassment zone, and the 
likelihood that a porpoise would engage in aversive behavior prior to 
experiencing PTS, we do not expect that any porpoise would be present 
within a Level A harassment zone for sufficient duration to actually 
experience PTS.
    Harbor Porpoise--Level B exposure estimates for harbor porpoise 
were calculated for each installation each year using the appropriate 
density given in table 8, the largest appropriate Zone of Influence 
(ZOI) for each pile type, and the appropriate number of construction 
days.
     NBK Bangor: Pile driving is not planned at this 
installation in year 1. For year 2, using the Hood Canal sub-region 
density, 36 days of pile driving in year 2, and the largest ZOIs 
calculated for each pile type at this location (31 km\2\ for vibratory 
installation of 36-in steel piles) produces an estimate of 905 
incidents of Level B harassment for harbor porpoise.
     NBK Bremerton: In year 1, using the Sinclair Inlet sub-
region density, 31 days of pile driving, and the largest ZOI calculated 
for each pile type at this location (16 km\2\ for removal and 
installation of 13-in timber piles, 0.2 km for impact installation of 
24-in concrete piles, and 0.07 km for impact installation of 18-in 
concrete) produces an estimate of 93 incidents of Level B harassment 
for harbor porpoise. In year 2, using the Sinclair Inlet sub-region 
density, 24 days of pile driving, and the largest ZOI calculated for 
each pile type at this location (16 km\2\ for vibratory removal and 
installation of 24-in steel piles) produces an estimate of 204 
incidents of Level B harassment for harbor porpoise.
     NBK Manchester: In year 1, using the Vashon sub-region 
density, 37 days of pile driving, and the largest ZOI calculated for 
each pile type at this location (75.8 km\2\ for DTH of 24-in concrete 
piles) produces an estimate of 701 incidents of Level B harassment for 
harbor porpoise. There are no pile driving activities planned at this 
installation in year 2.
     Naval Station (NS) Everett: There are no pile driving 
activities planned at this installation in year 1. In year 2, using the 
East Whidbey sub-region density, 8 days of pile driving, and the 
largest ZOI calculated each pile type at this location (8 km\2\) 
produces an

[[Page 47547]]

estimate of 24 incidents of Level B harassment for harbor porpoise.
    The Navy plans to implement shutdown of pile driving activity at 
any time if a harbor porpoise is observed in the Level A harassment 
zone. As a result of this planned mitigation, we do not believe that 
Level A harassment is a likely outcome. There are two instances where 
the Level A harassment zone may extend beyond a distance where harbor 
porpoise may reliably be detected by protected species observers 
(PSOs). In year 1, the Level A harassment zone is 445 m during DTH 
drilling of 24-in concrete at NBK Manchester. In year 2, the Level A 
harassment zone is 645 m during impact driving of 36-in steel piles 
with a bubble curtain at NBK Bangor. However, Rone et al. (2024) 
reported a notable absence of harbor porpoise within 21 km\2\ in front 
of NBK Bangor. In both cases, harbor porpoise are uncommon in the area. 
Given the Navy's commitment to shut down upon observation of a porpoise 
within the Level A harassment zone, and the likelihood that a porpoise 
would engage in aversive behavior prior to experiencing PTS, we do not 
expect that any porpoise would be present within a Level A harassment 
zone for sufficient duration to actually experience PTS.
    Across all installations, we propose to authorize 794 takes by 
Level B harassment of harbor porpoise in year 1 and 1,157 takes by 
Level B harassment of harbor porpoise in year 2.
    Steller Sea Lion--Level B harassment estimates for Steller sea 
lions were calculated for each installation using the appropriate 
density given in table 8 or site-specific abundance, the largest 
appropriate ZOI for each pile type at each installation, and the 
appropriate number of days. Please see Marine Mammal Monitoring Report 
at Navy Region Northwest Installations: 2008-2022 (https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities) for details of site-
specific abundance information (Navy, 2023).
     NBK Bangor: Steller sea lions are routinely seen hauled 
out from mid-September through May, with a maximum daily haulout count 
of 21 individuals in November (based on data collected between 2008 and 
2022). Because the mean of monthly average counts per surveys between 
2008-2022 was 1, we relied the average of the maximum count of hauled 
out Steller sea lions for each month in the in-water work window (July-
January). The average of the monthly maximum counts during the in-water 
work window provides an estimate of 7.25 sea lions present per day. 
Using this value for 36 days in year 2 results in an estimate of 261 
incidents of Level B harassment in year 2. There are no pile driving 
activities planned at this installation in year 1.
     NBK Bremerton: Steller sea lions have been documented only 
twice at this installation between 2008 and 2022. As such density 
values were used to estimate take at this location. Using the Puget 
Sound density value for fall-winter, 31 days of pile driving in year 1, 
and the largest ZOI calculated for each pile type at this location (16 
km\2\ for removal and installation of 13-in timber piles, 0.2 km for 
impact installation of 24-in concrete piles, and 0.07 km for impact 
installation of 18-in concrete) produces an estimate of 9 incidents of 
Level B harassment for Steller sea lion in year 1. Using the Puget 
Sound density value for fall-winter, 24 days of pile driving in year 2, 
and the largest ZOI calculated for each pile type at this location (16 
km\2\ for vibratory removal and installation of 24-in steel piles) 
produces an estimate of 18 incidents of Level B harassment for Steller 
sea lion in year 2.
     NBK Manchester: Steller sea lions are observed 
periodically at NBK Manchester since surveys began in 2012. We estimate 
take based on the monthly mean counts per surveys conducted from July 
to February, between 2012 and 2022, which provides an estimate of six 
Steller sea lions per day. In year 1, using this value for 37 days in 
results in an estimate of 222 incidents of Level B harassment. There 
are no pile driving activities planned at this installation in year 2.
     NS Everett: Steller sea lions were rarely observed at NS 
Everett between 2012 and 2022. All observations were of lone 
individuals hauled out on a Port Security Barrier (PSB) or in a nearby 
basin. We conservatively estimate that one Steller sea lion could occur 
within the project area per day. Using this value for 8 days in year 2 
results in an estimate of 8 incidents of Level B harassment in year 2. 
There are no pile driving activities planned at this installation in 
year 1.
    Given the small size of calculated Level A harassment zones--
maximum of 15 m for the worst-case scenario of DTH-installed 24-in 
concrete piles in year 1 and maximum of 21 m for the worst-case 
scenario of impact-driven 36-in steel piles with the use of a bubble 
curtain in year 2--we do not anticipate any potential for Level A 
harassment of Steller sea lions.
    Across all installations we propose to authorize take by 231 takes 
by Level B harassment of Steller sea lion in year 1 and 287 takes by 
Level B harassment of Steller sea lions in year 2.
    California Sea Lion--Level B harassment estimates for California 
sea lions were calculated for each installation using the appropriate 
site-specific abundance, the largest appropriate ZOI for each pile type 
at each installation, and the appropriate number of days. Please see 
Marine Mammal Monitoring Report at Navy Region Northwest Installations: 
2008-2022 (https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities) for 
details of site-specific abundance information (Navy, 2023).
     NBK Bangor: California sea lions haul out in all months on 
floating PSB and on submarines docked at Delta Pier, with lower numbers 
in June through July. We estimate take based on the monthly mean counts 
per surveys conducted from July to January, between 2012 and 2022, 
which provides an estimate of 25 California sea lions per day. In year 
2, using this value for 36 days results in an estimate of 900 incidents 
of Level B harassment in year 2. There are no pile driving activities 
planned at this installation in year 1.
     NBK Bremerton: California sea lions are routinely seen 
hauled out on floats at NBK Bremerton during most of the year. We 
estimate take based on the monthly mean count per surveys conducted 
from July through February, between 2010 and 2022, which provides an 
estimate of 98 California sea lions per day. In year 1, using this 
value for 31 days generates an estimate of 3,038 incidents of Level B 
harassment. In year 2, using this value for 24 days generates an 
estimate of 2,352 incidents of Level B harassment in year 2.
     NBK Manchester: California sea lions have been observed at 
this installation at least once each month of the year, with peak 
numbers occurring in October and November. Floats used as haulouts are 
periodically installed and removed, making numbers in the vicinity 
highly variable. We estimate take based on the monthly mean count per 
surveys conducted from July through February, between 2012 and 2022, 
which provides an estimate of 24 California sea lions per day. In year 
1, using this value for 37 days generates an estimate of 1,274 
incidents of Level B harassment. There are no pile driving activities 
planned at this installation in year 2.
     NS Everett: California sea lions have been observed every 
month of the year. We estimate take based on the monthly mean count per 
survey conducted from July through February

[[Page 47548]]

between 2012 and 2022, which provides an estimate of 48 California sea 
lions per day. In year 2, using this value for 8 days in year 2 
generates an estimate of 384 incidents of Level B exposures. There are 
no pile driving activities planned at this installation in year 1.
    Given the small size of calculated Level A harassment zones--
maximum of 15 m for the worst-case scenario of DTH-installed 24-in 
concrete piles in year 1 and maximum of 21 m for the worst-case 
scenario of impact-driven 36-in steel piles with the use of a bubble 
curtain in year 2--we do not anticipate any potential for Level A 
harassment of California sea lions.
    Across all installations we propose to authorize 3,926 takes by 
Level B harassment of California sea lions in year 1 and 3,636 takes by 
Level B harassment of California sea lions in year 2.
    Harbor Seal--Harbor seals are expected to occur year-round at all 
installations, with the greatest numbers expected at installations with 
nearby haul-out sites. Level B exposure estimates for harbor seals were 
calculated for each installation using the appropriate site-specific 
abundance, the largest appropriate ZOI for each pile type at each 
installation, and the appropriate number of days. Please see Marine 
Mammal Monitoring Report at Navy Region Northwest Installations: 2008-
2022 (https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities) for details of 
site-specific abundance information (Navy, 2023).
    Harbor seals are expected to be the most abundant marine mammal at 
all installations, often occurring in and around existing in-water 
structures in a way that may restrict observers' ability to adequately 
observe seals and subsequently implement shutdowns. In addition, the 
calculated Level A harassment zones are significantly larger than those 
for sea lions, which may also be abundant at various installations at 
certain times of year. For harbor seals in year 1, the largest 
calculated Level A harassment zone is 200 m (compared with a maximum 
zone of 15 m for sea lions), calculated for the worst-case scenario of 
DTH-installed 24-in concrete piles (other scenarios range from 5-75 m). 
In year 2, the largest calculated Level A harassment zone is 290 m 
(compared with a maximum zone of 21 m for sea lions), calculated for 
the worst-case scenario of impact-driven 36-in steel piles with the use 
of a bubble curtain (other scenarios range from 1-21 m). Therefore, we 
assume that some Level A harassment is likely to occur for harbor seals 
and provide installation-specific estimates below.
     NBK Bangor: Harbor seals are year-round residents at NBK 
Bangor and have been identified at least once during each calendar 
month over several survey years. They have been observed swimming and 
hauled out on man-made structures including docks, catwalks under the 
dock at Marginal Pier, PSBs, and boats along the NBK Bangor waterfront, 
The Navy plans to place fencing around the catwalks at Marginal Pier, 
which may reduce harbor seal haulout opportunities at NBK Bangor. 
Because the mean of monthly average counts per surveys between 2008-
2022 was <1, we estimate take by Level B harassment based on the mean 
maximum count per month of surveys conducted from July to January, 
between 2008 and 2022, which provides an estimate of 16 harbor seals 
per day. In year 2, using this value for 36 days results in an estimate 
of 576 incidents of Level B exposures. There are no pile driving 
activities planned at this installation in year 1.
    The Level A harassment zone expected to occur during impact 
installation of 36-in steel at NBK Bangor is 290 m. Since the Navy 
plans to maintain a shutdown zone of at 180 m (see table 11), the Navy 
estimates and NMFS agrees that one seal per day (n = 20) could remain 
within the calculated Level A harassment zone for a sufficient period 
to accumulate enough energy to result in PTS. As such, we propose to 
authorize 20 incidents of take by Level A harassment.
     NBK Bremerton: Observations of harbor seals are 
intermittent at NBK Bremerton. They are primarily observed swimming in 
the water around piers and structures and less frequently hauled out on 
floats and docked submarines. Because the mean of monthly average 
counts per surveys between 2008-2022 was <1, we estimate take based on 
the mean maximum count per month of surveys from July to February, 
between 2010 and 2022, which provides an estimate of two harbor seals 
per day. In year 1, using this value for 31 days results in an estimate 
of 62 incidents of Level B exposures. In year 2, using this value for 
24 days results in an estimate of 48 incidents of Level B harassment.
    In year 1, the Level A harassment zone expected to occur during 
impact installation of 18-in steel at NBK Bremerton is 39 m and the 
Level A harassment zone expected to occur during impact installation of 
24-in steel is 73 m. Although the Navy plans to shut down at distances 
slightly larger than these Level A harassment zones (see table 10), the 
Navy assumes and NMFS agrees that it is possible that one seal per day 
could go unobserved and remain within the calculated zone for a 
sufficient period to accumulate enough energy to result in PTS. As 
such, we propose to authorize 20 takes by Level A harassment. In year 
2, the largest Level A harassment zone is much smaller (<10 m) and as 
such we do not expect take by Level A harassment to occur and we do not 
propose to authorize such take.
     NBK Manchester: No harbor seal haulouts have been 
identified at NBK Manchester, but seals regularly haul out at Orchard 
Rocks and are observed swimming through the project area. We estimate 
take based on the monthly mean count per survey conducted from July 
through February between 2020 and 2022 (Orchard Rocks was incorporated 
into surveys in 2020), which provides an estimate of 10 harbor seals 
per day. In year 1, using this value for 37 days results in an estimate 
of 370 incidents of Level B harassment. There are no pile driving 
activities planned at this installation in year 2.
    The Level A harassment zone expected to occur during DTH 
installation of 24-in concrete at NBK Manchester is 200 m. Since the 
Navy plans to shut down at 150 m due to practicability concerns (see 
table 10), the Navy assumes and NMFS agrees that one seal per day (n = 
37) could remain within the calculated zone for a sufficient period to 
accumulate enough energy to result in PTS. As such, we propose to 
authorize 37 incidents of take by Level A harassment.
     NS Everett: Harbor seals haul out year round on floats, 
riprap, and human structures at NS Everett. We estimate take based on 
the monthly mean count per survey conducted from July through February 
between 2019 and 2022 (the east side of East Waterway was incorporated 
into surveys in 2019), which provides an estimate of 266 harbor seals 
per day. In year 2, using this value for 8 days results in an estimate 
of 2,128 incidents of Level B harassment. There are no planned pile 
driving activities at this installation in year 1.
    The largest Level A harassment zone expected to occur at NS Everett 
is 21 m and the Navy plans to shut down at this distance should a 
harbor seal be observed entering or within this zone. As such we do not 
expect take by Level A harassment to occur and we do not propose to 
authorize such take here.
    Any individuals exposed to the higher levels associated with the 
potential for PTS closer to the source might also be behaviorally 
disturbed, however, for the

[[Page 47549]]

purposes of quantifying take we do not count those exposures of one 
individual as both a Level A harassment take and a Level B harassment 
take, and therefore takes by Level B harassment calculated as described 
above are further modified to deduct the amount of take by Level A 
harassment. Therefore, in year 1, across all installations, NMFS 
proposes to authorize 57 takes by Level A harassment and 432 takes by 
Level B harassment for harbor seal, for a total of 489 takes. In year 
2, across all installations, NMFS proposes to authorize 20 takes by 
Level A harassment and 2,752 takes by Level B harassment for harbor 
seal, for a total of 2,772 takes.
    Northern Elephant Seal--Northern elephant seals are considered rare 
visitors to Puget Sound. However, solitary juvenile elephant seals have 
been known to sporadically haul out to molt in Puget Sound during 
spring and summer months. Because there are occasional sightings in 
Puget Sound, the Navy reasons that exposure of up to one seal to noise 
above Level B harassment thresholds could occur for a 2-day duration 
for a total of two takes by Level B harassment of northern elephant 
seals each year.
    The total take authorization for all species each year is 
summarized in table 9 below. No authorization of take by Level A 
harassment is authorized except a total of 57 such incidents for harbor 
seals in year 1 and 20 such incidents for harbor seals in year 2.

                                                    Table 9--Take Authorization by Level B Harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                           Year 1                                  Year 2
                                                                          ------------------------------------------------------------------------------
                                                                                                       Take as a                              Take as a
                  Species                               Stock                Level A      Level B     percentage     Level A      Level B     percentage
                                                                            harassment   harassment    of stock     harassment   harassment    of stock
                                                                                                       abundance                              abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback Whale............................  CenAmer./S Mex-CA-OR-WA......            0            0            0             0            0            0
                                            Mex-CA-OR-WA.................                         1           <1             0            1           <1
                                            Hawai[revaps]i...............                         3           <1             0            3           <1
Minke Whale...............................  CA-OR-WA.....................            0            4           <1             0            4           <1
Gray Whale................................  Eastern N Pacific............            0            4           <1             0            4           <1
Killer Whale..............................  W Coast Transient............            0           12            3             0           12            3
                                            E.N.P.--S Resident...........            0           20           27             0           20           27
Harbor Porpoise...........................  WA. Inland...................            0          794            7             0        1,157           10
Dall's Porpoise...........................  CA-OR-WA.....................            0           10           <1             0           10           <1
Steller Sea Lion..........................  Eastern US...................            0          231           <1             0          287           <1
California Sea Lion.......................  US...........................            0        3,926            2             0        3,636          1.4
Northern Elephant Seal....................  CA Breeding..................            0            2           <1             0            2           <1
Harbor Seal...............................  WA N Inland..................           57          375            4             0        2,176           13
                                            Hood Canal...................            0            0            0            20          576           17
--------------------------------------------------------------------------------------------------------------------------------------------------------

Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting the 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks, and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, NMFS 
considers two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned); and
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, and impact on 
operations.
    Timing--As described previously, the Navy will adhere to in-water 
work windows designed for the protection of fish. These timing windows 
would also benefit marine mammals by limiting the annual duration of 
construction activities. At NBK Bangor, the Navy will adhere to a July 
16 through January 15 window, while at the remaining facilities this 
window is extended to February 15 each project year.
    On a daily basis, in-water construction activities will occur only 
during daylight hours (sunrise to sunset) except from July 16 to 
September 15, when impact pile driving will only occur starting 2 hours 
after sunrise and ending 2 hours before sunset in order to protect 
marbled murrelets (Brachyramphus marmoratus) during the nesting season. 
The exception is NBK Bremerton, where marbled murrelets do not occur.
    Shutdown Zone--For all pile driving, removal, and DTH drilling, the 
Navy will implement shutdowns within designated zones. The purpose of a 
shutdown zone is generally to define an area within which shutdown of 
activity would occur upon sighting of a marine mammal (or in 
anticipation of an animal entering the defined area). For all pile 
driving activities, the Navy will establish a minimum shutdown zone 
with a radial distance of 10 m. This minimum zone is intended to 
prevent the already unlikely possibility of physical interaction with 
construction equipment and to establish a precautionary minimum zone 
with regard to acoustic effects. In most circumstances where the 
predicted Level A harassment zone exceeds the minimum zone, the Navy 
proposes to implement a shutdown zone greater or equal to the predicted 
Level A harassment zone (see tables 12 and 13). However, in cases where 
it would be challenging to detect marine mammals at the Level A 
harassment isopleth and frequent shutdowns would create practicability 
concerns (e.g., for phocids

[[Page 47550]]

during DTH at NBK Manchester in year 1 and impact pile driving at NBK 
Bangor in year 2), smaller shutdown zones have been established. In 
addition, the Navy proposes to implement shutdown upon observation of 
any large whales and killer whales within a calculated Level B 
harassment zone. Recognizing that the entirety of the Level B 
harassment zone cannot practicably be monitored, the Orca Network would 
be consulted prior to commencing pile driving each day, and pile 
driving would also be delayed or shutdown if low-frequency or mid-
frequency cetaceans are reported near or approaching the Level B 
harassment zone. In all cases, predicted injury zones are calculated on 
the basis of cumulative sound exposure, as peak pressure source levels 
produce smaller predicted zones.
    Finally, construction activities will be halted upon observation of 
a species for which incidental take is not authorized or a species for 
which incidental take has been authorized but the authorized number of 
takes has been met entering or within the harassment zone.

                                                            Table 10--Shutdown Zones, Year 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                  Shutdown zones (m)                          Level B         Level B
              Activity                    Pile size/type     ------------------------------------------------------------   harassment      monitoring
                                                                  LF          MF          HF          PW          OW         zone (m)        zone (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation.................  18-in Concrete........         100          50         100          40          10              46             N/A
                                      24-in Concrete........         170          90         170          75          10              86             N/A
Vibratory Installation or Removal...  13-in Timber..........   \2\ 5,412   \2\ 5,412          15          10          10           5,412         \1\ 400
DTH.................................  24-in Concrete........  \2\ 13,594  \2\ 13,594     \3\ 450         150          20          13,594         \1\ 450
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Observers must be able to monitor at minimum the Level B monitoring zone prior to commencing vibratory pile driving and removal and DTH drilling.
\2\ This shutdown zone likely extends beyond the distance that low- and mid-frequency cetaceans can be reliably detected. Observers will monitor this
  shutdown zone to the maximum extent possible based on the number and location of PSOs deployed and weather conditions.
\3\ This shutdown zone likely extends beyond the distance that harbor porpoise can be reliably detected. However, harbor porpoise are uncommon near NKB
  Manchester, and it is likely that they would engage in aversive behavior prior to experiencing PTS. As such, we do not expect that any porpoise would
  be present within a Level A harassment zone for sufficient duration to actually experience PTS.


                                                            Table 11--Shutdown Zones, Year 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                  Shutdown zones (m)                          Level B         Level B
              Activity                    Pile size/type     ------------------------------------------------------------   harassment      monitoring
                                                                  LF          MF          HF          PW          OW         zone (m)        zone (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation.................  12-in Steel...........          50          50          50          30          10            39.8             N/A
                                      36-in Steel...........         650         650     \3\ 650         180          25           541.2             N/A
Vibratory Installation or Removal...  12-in Steel...........       1,585       1,585          10          10          10           1,585         \1\ 400
                                      24-in Steel...........   \2\ 5,412   \2\ 5,412          15          10          10           5,412         \1\ 400
                                      36-in Steel...........  \2\ 11,659  \2\ 11,659          40          20          10          11,659         \1\ 400
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Observers must be able to monitor at minimum the Level B monitoring zone prior to commencing vibratory pile driving and removal.
\2\ This shutdown zone likely extends beyond the distance that low- and mid-frequency cetaceans can be reliably detected. Observers will monitor this
  shutdown zone to the maximum extent possible based on the number and location of deployed PSOs and weather conditions.
\3\ This shutdown zone likely extends beyond the distance that harbor porpoise can be reliably detected. However, harbor porpoise were notably absent
  within 21 km\2\ in front of NKB Bangor (Rone et al., 2024) and it is likely that they would engage in aversive behavior prior to experiencing PTS. As
  such, we do not expect that any porpoise would be present within a Level A harassment zone for sufficient duration to actually experience PTS.

    Protected Species Observers--The number and placement of PSOs 
during all construction activities (described in the Monitoring and 
Reporting section) would ensure that the entire shutdown zone is 
visible, except in cases when the shutdown zone is based on the Level B 
harassment zone (large whales and killer whales). In such cases, PSOs 
must be able to monitor at minimum the Level A harassment zone. The 
Navy will employ at least three PSOs for all pile driving and DTH 
drilling.
    Monitoring for Level B Harassment--PSOs will monitor the shutdown 
zones and beyond to the extent that PSOs can see. Monitoring beyond the 
shutdown zones enables observers to be aware of and communicate the 
presence of marine mammals in the project areas outside the shutdown 
zones and thus prepare for a potential cessation of activity should the 
animal enter the shutdown zone. Additionally, prior to commencing pile 
driving, PSOs will contact Navy marine biologists or the Orca Network 
directly to obtain reports of large whales in the area.
    In order to document observed incidents of harassment, PSOs record 
all marine mammal observations, regardless of location. The PSO's 
location and the location of the pile being driven are known, and the 
location of the animal may be estimated as a distance from the observer 
and then compared to the location from the pile. It may then be 
estimated whether the animal was exposed to sound levels constituting 
incidental harassment on the basis of predicted distances to relevant 
thresholds in post-processing of observational data, and a precise 
accounting of observed incidents of harassment created.
    Pre and Post-Activity Monitoring--Prior to the start of daily in-
water construction activity, or whenever a break in pile driving of 30 
minutes or longer occurs, PSOs will observe the shutdown zone, Level A 
harassment zone, and Level B harassment zone (to the extent possible 
based on the number and location of PSOs and weather conditions) for a 
period of 30 minutes. Pre-start clearance monitoring must be conducted 
during periods of visibility sufficient for the lead PSO to determine 
that the shutdown zones and, during vibratory driving and removal and 
DTH drilling, the Level B monitoring zone, are clear of marine mammals. 
If these zones are obscured by fog or poor lighting conditions, in-
water construction activity will not be initiated until the entire 
shutdown zone is visible. Pile driving may commence following 30 
minutes of observation when the determination is made that the shutdown 
zones and, during vibratory driving and removal and DTH drilling, the 
Level B monitoring zone, are clear of marine mammals. If a marine 
mammal is observed entering or within these zones, pile driving 
activity must be delayed or halted. During vibratory driving and 
removal and DTH, the Navy will shut down upon any observation of large 
whales and killer whales. If pile driving is delayed or halted due to 
the

[[Page 47551]]

presence of a marine mammal, the activity may not commence or resume 
until either the animal has voluntarily exited and been visually 
confirmed beyond the shutdown zone or 15 minutes have passed without 
re-detection of the animal.
    The Navy also plans to take measures to ensure that killer whales 
and large cetaceans (i.e., humpback whale, gray whale, and minke whale) 
are not located within the vicinity of the project area, including, but 
not limited to, contacting and/or reviewing the latest sightings data 
from the Orca Network and/or Center for Whale Research, including 
passive acoustic detections, to determine the location of the nearest 
marine mammal sightings.
    Soft Start--The use of a soft start procedure is believed to 
provide additional protection to marine mammals by warning marine 
mammals or providing them with a chance to leave the area prior to the 
hammer operating at full capacity. The Navy will utilize soft start 
techniques for impact pile driving. We require an initial set of three 
strikes from the impact hammer at reduced energy, followed by a 30-
second waiting period, then two subsequent three-strike sets. Soft 
start will be required at the beginning of each day's impact pile 
driving work and at any time following a cessation of impact pile 
driving of 30 minutes or longer; the requirement to implement soft 
start for impact driving is independent of whether vibratory driving 
has occurred within the prior 30 minutes. Soft start is not required 
during vibratory pile driving activities.
    Bubble Curtain--A bubble curtain will be used for all impact 
driving of steel piles to attenuate noise. A bubble curtain will be 
employed during impact installation or proofing of steel pile where 
water depths are greater than 2 ft (0.67 m). Bubble curtains are not 
planned for installation of other pile types due to the relatively low 
source levels, as the requirement to deploy the curtain system at each 
driven pile results in a significantly lower production rate. Where a 
bubble curtain is used, the contractor will be required to turn it on 
prior to the soft start in order to flush fish from the area closest to 
the driven pile.
    To avoid loss of attenuation from design and implementation errors, 
the Navy will require specific bubble curtain design specifications, 
including testing requirements for air pressure and flow at each 
manifold ring prior to initial impact hammer use, and a requirement for 
placement on the substrate. The bubble curtain must distribute air 
bubbles around 100 percent of the piling perimeter for the full depth 
of the water column. The lowest bubble ring shall be in contact with 
the mudline for the full circumference of the ring, and the weights 
attached to the bottom ring shall ensure 100 percent mudline contact. 
No parts of the ring or other objects shall prevent full mudline 
contact. The contractor shall also train personnel in the proper 
balancing of air flow to the bubblers, and must submit an inspection/
performance report to the Navy for approval within 72 hours following 
the performance test. Corrections to the noise attenuation device to 
meet the performance standards shall occur prior to use for impact 
driving.
    Based on our evaluation of the applicant's planned measures, NMFS 
has determined that the mitigation measures provide the means of 
effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that 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 
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 while 
conducting the activities. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
     Mitigation and monitoring effectiveness.
    Visual Monitoring--Marine mammal monitoring must be conducted in 
accordance with the Marine Mammal Monitoring and Mitigation Plan. 
Marine mammal monitoring during pile driving and removal and DTH 
drilling must be conducted by NMFS-approved PSOs in a manner consistent 
with the following:
     PSOs must be independent of the activity contractor (for 
example, employed by a subcontractor), and have no other assigned tasks 
during monitoring periods;
     At least one PSO must have prior experience performing the 
duties of a PSO during construction activity pursuant to a NMFS-issued 
incidental take authorization;
     Other PSOs may substitute other relevant experience, 
education (degree in biological science or related field) or training 
for experience performing the duties of a PSO during construction 
activities pursuant to a NMFS-issued incidental take authorization;
     Where a team of three or more PSOs is required, a lead 
observer or monitoring coordinator will be designated. The lead 
observer will be required to have prior experience working as a marine 
mammal observer during construction activity pursuant to a NMFS-issued 
incidental take authorization; and
     PSOs must be approved by NMFS prior to beginning any 
activity subject to each IHA.
    PSOs should also have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;

[[Page 47552]]

     Writing skills sufficient to prepare a report of 
observations including, but not limited to, the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was note implemented when required); 
and marine mammal behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    Visual monitoring will be conducted by a minimum of three trained 
PSOs positioned at suitable vantage points practicable (e.g., from a 
small boat, the pile driving barge, on shore, piers, or any other 
suitable location). One PSO will have an unobstructed view of all water 
within the shutdown zone, and during vibratory pile driving and removal 
and DTH drilling, the Level B monitoring zone. Remaining PSOs will 
observe as much as the Level A and Level B harassment zones as 
possible.
    Monitoring will be conducted 30 minutes before, during, and 30 
minutes after all in water construction activities. In addition, PSOs 
will record all incidents of marine mammal occurrence, regardless of 
distance from activity, and will document any behavioral reactions in 
concert with distance from piles being driven or removed. Pile driving 
activities include the time to install or remove a single pile or 
series of piles, as long as the time elapsed between uses of the pile 
driving equipment is no more than 30 minutes.

Acoustic Monitoring

    The Navy plans to conduct hydroacoustic monitoring for a subset of 
impact-driven steel piles for projects including more than three piles 
where a bubble curtain is used (relevant to year 2 project activities 
only).

Reporting

    The Navy will submit a draft marine mammal monitoring report to 
NMFS within 90 days after the completion of pile driving activities, or 
60 days prior to a requested date of issuance of any future IHAs for 
the project, or other projects at the same location, whichever comes 
first. The marine mammal monitoring report will include an overall 
description of work completed, a narrative regarding marine mammal 
sightings, and associated PSO data sheets. Specifically, the report 
will include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including: (1) The number and type of piles that 
were driven and the method (e.g., impact or vibratory); and (2) Total 
duration of driving time for each pile (vibratory driving) and number 
of strikes for each pile (impact driving);
     PSO locations during marine mammal monitoring;
     Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
     Upon observation of a marine mammal, the following 
information: (1) Name of PSO who sighted the animal(s) and PSO location 
and activity at time of sighting; (2) Time of sighting; (3) 
Identification of the animal(s) (e.g., genus/species, lowest possible 
taxonomic level, or unidentified), PSO confidence in identification, 
and the composition of the group if there is a mix of species; (4) 
Distance and location of each observed marine mammal relative to the 
pile being driven for each sighting; (5) Estimated number of animals 
(min/max/best estimate); (6) Estimated number of animals by cohort 
(adults, juveniles, neonates, group composition, etc.); (7) Animal's 
closest point of approach and estimated time spent within the 
harassment zone; and (8) Description of any marine mammal behavioral 
observations (e.g., observed behaviors such as feeding or traveling), 
including an assessment of behavioral responses thought to have 
resulted from the activity (e.g., no response or changes in behavioral 
state such as ceasing feeding, changing direction, flushing, or 
breaching);
     Number of marine mammals detected within the harassment 
zones, by species; and
     Detailed information about implementation of any 
mitigation (e.g., shutdowns and delays), a description of specific 
actions that ensued, and resulting changes in behavior of the 
animal(s), if any.
    A final report must be prepared and submitted within 30 calendar 
days following receipt of any NMFS comments on the draft report. If no 
comments are received from NMFS within 30 calendar days of receipt of 
the draft report, the report will be considered final. All PSO data 
will be submitted electronically in a format that can be queried such 
as a spreadsheet or database and will be submitted with the draft 
marine mammal report.
    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the Holder must report the 
incident to the Office of Protected Resources (OPR), NMFS 
([email protected] and [email protected]) and the 
West Coast Regional Stranding Coordinator as soon as feasible. If the 
death or injury was clearly caused by the specified activity, the 
Holder must immediately cease the activities until NMFS OPR is able to 
review the circumstances of the incident and determine what, if any, 
additional measures are appropriate to ensure compliance with the terms 
of the IHAs. The Holder must not resume their activities until notified 
by NMFS. The report must include the following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
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 harassment, NMFS considers other factors, such as the 
likely nature of any impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), 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

[[Page 47553]]

preamble for NMFS' implementing regulations (54 FR 40338, September 29, 
1989), the impacts from other past and ongoing anthropogenic activities 
are incorporated into this analysis via their impacts on the baseline 
(e.g., as reflected in the regulatory status of the species, population 
size and growth rate where known, ongoing sources of human-caused 
mortality, or ambient noise levels).
    To avoid repetition, the majority of our analysis applies to all 
the species listed in table 1, given that many of the anticipated 
effects of this project on different marine mammal stocks are expected 
to be relatively similar in nature. Where there are meaningful 
differences between species or stocks, or groups of species, in 
anticipated individual responses to activities, impact of expected take 
on the population due to differences in population status, or impacts 
on habitat, they are described independently in the analysis below.
    Pile driving activities associated with the maintenance projects, 
as described previously, have the potential to disturb or displace 
marine mammals. Specifically, the specified activities may result in 
take, in the form of Level B harassment (behavioral disturbance) only 
(for all species other than harbor seal) from underwater sounds 
generated from pile driving. Potential takes could occur if individual 
marine mammals are present in the ensonified zone when pile driving is 
happening.
    No serious injury or mortality would be expected even in the 
absence of the planned mitigation measures. For all species other than 
the harbor seal, no Level A harassment is anticipated given the nature 
of the activities, i.e., much of the anticipated activity would involve 
measures designed to minimize the possibility of injury. The potential 
for injury is small for cetaceans and sea lions, and is expected to be 
essentially eliminated through implementation of the mitigation 
measures--use of the bubble curtain for steel piles (relevant to year 2 
only), soft start (for impact driving), and shutdown zones. Impact 
driving, as compared with vibratory driving, has source characteristics 
(short, sharp pulses with higher peak levels and much sharper rise time 
to reach those peaks) that are potentially injurious or more likely to 
produce severe behavioral reactions. Given sufficient notice through 
use of soft start, marine mammals are expected to move away from a 
sound source that is annoying prior to becoming potentially injurious 
or resulting in more severe behavioral reactions. Additionally, 
environmental conditions in inland waters are expected to generally be 
good, with calm sea states, and we expect conditions would allow a high 
marine mammal detection capability, enabling a high rate of success in 
implementation of shutdowns to avoid injury.
    As described previously, there are multiple species that are 
considered rare in the project areas and for which we authorize limited 
take, by Level B harassment, of a single group for a minimal period of 
time in each authorization year (1 or 2 days).
    ESA critical habitat for southern resident killer whale occurs in 
Puget Sound (see the Description of Marine Mammals in the Area of 
Specified Activities section of this notice). NMFS did not identify in-
water sound levels as a separate essential feature of critical habitat, 
though anthropogenic sound is recognized as one of the primary threats 
to SRKW (NMFS, 2019). The exposure of SRKW to sound from the planned 
activities would be minimized by the required mitigation measures 
(e.g., shutdown zones equivalent to the Level B harassment zones). The 
effects of the activities on SRKW habitat generally, such as 
sedimentation and impacts to availability of prey species, are expected 
to be limited both spatially and temporally, constrained to the 
immediate area around the pile driver(s) at each pier and returning to 
baseline levels quickly. Additionally, the timing of the in-water work 
window for the projects is intended to limit impacts to ESA-listed 
fishes, which would accordingly reduce potential impacts to SRKW prey.
    Puget Sound is part of a biologically important area (BIA) for 
migrating gray whales (Calambokidis et al., 2015). However, gray whales 
in this area typically remain further north, primarily in the waters 
around Whidbey Island (Calambokidis et al., 2018) (an area where only 8 
days of pile driving are planned). Therefore, even though the project 
areas overlap with the BIA, the infrequent occurrence of gray whales 
suggests that the projects would have minimal, if any, impact on the 
migration of gray whales, and would therefore not affect reproduction 
or survival.
    Aside from the SRKW critical habitat and BIA for gray whales, there 
are no known important areas for other marine mammals, such as feeding 
or pupping areas. Therefore, we do not expect meaningful impacts to 
these species (i.e., humpback whale, gray whale, minke whale, transient 
and resident killer whales, Dall's porpoise, and northern elephant 
seal) and find, for both the year 1 and year 2 IHAs, that the total 
marine mammal take from the specified activities will have a negligible 
impact on these marine mammal species.
    For remaining species (harbor porpoise, California sea lion, 
Steller sea lion, and harbor seal), we discuss the likely effects of 
the specified activities in greater detail. Effects on individuals that 
are taken by Level B harassment, on the basis of reports in the 
literature as well as monitoring from other similar activities, will 
likely be limited to reactions such as increased swimming speeds, 
increased surfacing time, or decreased foraging (if such activity were 
occurring) (e.g., Thorson and Reyff, 2006; HDR, Inc., 2012; Lerma, 
2014). Most likely, individuals will simply move away from the sound 
source and be temporarily displaced from the areas of pile driving, 
although even this reaction has been observed primarily only in 
association with impact pile driving.
    The Navy has conducted multi-year activities potentially affecting 
marine mammals, and typically involving greater or similar levels of 
activity than is contemplated here in various locations, such as San 
Diego Bay, and some of the installations considered herein (NBK Bangor, 
NBK Bremerton, NBK Manchester). Reporting from these activities has 
similarly reported no apparently consequential behavioral reactions or 
long-term effects on marine mammal populations (Lerma, 2014; Navy, 
2016; Sandoval et al., 2022; Sandoval and Johnson, 2022; Hamer 
Environmental 2021; DoN, 2021 and 2022). Repeated exposures of 
individuals to relatively low levels of sound outside of preferred 
habitat areas are unlikely to significantly disrupt critical behaviors. 
Thus, even repeated Level B harassment of some small subset of the 
overall stock is unlikely to result in any significant realized 
decrease in viability for the affected individuals, and thus would not 
result in any adverse impact to the stock as a whole. Level B 
harassment will be reduced to the level of least practicable adverse 
impact through use of mitigation measures described herein and, if 
sound produced by project activities is sufficiently disturbing, 
animals are likely to simply avoid the area while the activity is 
occurring. While vibratory driving and DTH drilling associated with 
some project components may produce sound at distances of many 
kilometers from the pile driving site, thus intruding on higher-quality 
habitat, the project sites themselves and the majority of sound fields 
produced by the specified activities are within industrialized areas. 
Therefore, we expect that animals

[[Page 47554]]

annoyed by project sound would simply avoid the area and use more-
preferred habitats.
    In addition to the expected effects resulting from authorized Level 
B harassment, we anticipate that harbor seals may sustain some limited 
Level A harassment in the form of auditory injury at two installations 
in year 1 (NBK Bremerton and NBK Manchester) and one installation in 
year 2 (NBK Bangor), assuming they remain within a given distance of 
the pile driving activity for the full number of pile strikes. However, 
seals in these locations that experience PTS would likely only receive 
slight PTS, i.e., minor degradation of hearing capabilities within 
regions of hearing that align most completely with the energy produced 
by pile driving, i.e., the low-frequency region below 2 kHz, not severe 
hearing impairment or impairment in the regions of greatest hearing 
sensitivity. If hearing impairment occurs, it is most likely that the 
affected animal would lose a few decibels in its hearing sensitivity, 
which in most cases is not likely to meaningfully affect its ability to 
forage and communicate with conspecifics. As described above, we expect 
that marine mammals would be likely to move away from a sound source 
that represents an aversive stimulus, especially at levels that would 
be expected to result in PTS, given sufficient notice through use of 
soft start.
    The pile driving activities are also not expected to have 
significant adverse effects on these affected marine mammals' habitats. 
The activities may cause some fish to leave the area of disturbance, 
thus temporarily impacting marine mammals' foraging opportunities in a 
limited portion of the foraging range; but, because of the short 
duration of the activities and the relatively small area of the habitat 
that may be affected (with no known particular importance to marine 
mammals), the impacts to marine mammal habitat are not expected to 
cause significant or long-term negative consequences.
    In combination, we believe that these factors, as well as the 
available body of evidence from other similar activities, demonstrate 
that the specified activities will have only minor, short-term effects 
on individuals that will not have any bearing on those individuals' 
fitness. Thus the specified activities are not expected to impact rates 
of recruitment or survival and will therefore have a negligible impact 
on those species or stocks.
    In summary and as described above, the following factors primarily 
support our determination that the impacts resulting from this activity 
are not expected to adversely affect any of the species or stocks 
through effects on annual rates of recruitment or survival:
     No serious injury or mortality is anticipated or 
authorized;
     The anticipated incidents of Level B harassment consist 
of, at worst, temporary modifications in behavior;
     The additional impact of PTS of a slight degree to few 
individual harbor seals at two locations in year 1 and one location in 
year 2 is not anticipated to increase individual impacts to a point 
where any population-level impacts might be expected;
     The absence of any significant habitat within the 
industrialized project areas, including known areas or features of 
special significance for foraging or reproduction; and
     The presumed efficacy of the mitigation measures in 
reducing the effects of the specified activity to the level of least 
practicable adverse impact.
     The effects on species that serve as prey for marine 
mammals from the activities are expected to be short-term and, 
therefore, any associated impacts on marine mammal feeding are not 
expected to result in significant or long-term consequences for 
individuals, or to accrue to adverse impacts on their populations from 
either project;
     The ensonifed areas from both projects are very small 
relative to the overall habitat ranges of all species and stocks, and 
will not cause more than minor impacts in any ESA-designated critical 
habitat, BIAs or any other areas of known biological importance.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the monitoring and mitigation 
measures, NMFS finds that the total marine mammal take from the 
activity, specific to each of the year 1 and year 2 IHAs, will have a 
negligible impact on all affected marine mammal species or stocks.

Small Numbers

    As noted previously, only take of small numbers of marine mammals 
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is less than one-third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    We propose to authorize incidental take of 14 marine mammal stocks 
each project year (table 9). The total amount of taking authorized is 
less than 1 percent for eight of these stocks in year 1 and year 2, 
equal or less than 10 percent for an additional four stocks in year 1 
and three stocks in year 2, and equal or less than 27 percent for 
another stock in year 1 and three stocks in year 2, all of which we 
consider relatively small percentages and thus small numbers of marine 
mammals relative to the estimated overall population abundances for 
those stocks.
    Based on the analysis contained herein of the activity (including 
the mitigation and monitoring measures) and the anticipated take of 
marine mammals, NMFS finds, for each of the year 1 and year 2 IHAs, 
that small numbers of marine mammals would be taken relative to the 
population size of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

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

Endangered Species Act

    Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.) 
requires that each Federal agency insure that any action it authorizes, 
funds, or carries out is not likely to jeopardize the continued 
existence of any endangered or threatened species or result in the 
destruction or adverse modification of designated critical habitat. To 
ensure ESA compliance for the issuance of IHAs, NMFS consults 
internally whenever we propose to authorize take for endangered or 
threatened species, in this case with the West Coast Regional Office.
    NMFS is authorizing take of SRKW, as well as two distinct 
population segments (DPSs) of humpback whale (Central American/Southern 
Mexico-California-Oregon-Washington and Mainland Mexico-California-
Oregon-

[[Page 47555]]

Washington), which are listed under the ESA.
    The NMFS OPR requested initiation of section 7 consultation with 
the NMFS West Coast Region (WCR) for the issuance of these IHAs. On 
April 29, 2024, WCR concluded that NMFS' current action remains covered 
by the programmatic Biological Opinion (WCRO-2016-00018) completed for 
the issuance of regulations preceding these IHAs (83 FR 9366, March 5, 
2018), and that reinitiation of the consultation is not required. WCR 
specified that the new IHAs are consistent with the original effects 
analysis included in the original programmatic opinion, and OPR's 
action would not change the conclusions nor the effects of the proposed 
action as written in the Biological Opinion.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must evaluate our action (i.e., the issuance of two consecutive 
IHAs) with respect to potential impacts on the human environment.
    This action is consistent with categories of activities identified 
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or 
mortality) of the Companion Manual for NAO 216-6A, which do not 
individually or cumulatively have the potential for significant impacts 
on the quality of the human environment and for which we have not 
identified any extraordinary circumstances that would preclude this 
categorical exclusion. Accordingly, NMFS has determined that the 
issuance of the IHAs qualifies to be categorically excluded from 
further NEPA review.

Authorization

    NMFS has issued two consecutive IHAs to the Navy for the potential 
harassment of small numbers of 10 marine mammal species incidental to 
the NAVFAC NW MPR Project in Puget Sound, Washington, that includes the 
previously explained mitigation, monitoring, and reporting 
requirements.

    Dated: May 28, 2024.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2024-12062 Filed 5-31-24; 8:45 am]
BILLING CODE 3510-22-P