[Federal Register Volume 89, Number 10 (Tuesday, January 16, 2024)]
[Notices]
[Pages 2584-2598]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-00622]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XC959]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Pile Driving and Removal To Improve 
the Auke Bay East Ferry Terminal

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

ACTION: Notice; issuance of an incidental harassment authorization.

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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 
Alaska Department of Transportation and Public Facilities (ADOT&PF) to 
incidentally harass, by Level A and Level B harassment, marine mammals 
during construction activities associated with a pile driving project 
for improvements to the Auke Bay East Ferry Terminal in Juneau, Alaska.

DATES: This authorization is effective from October 1, 2024 through 
September 30, 2025.

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/action/incidental-take-authorization-alaska-department-transportation-pile-driving-and-removal. In case of problems accessing these documents, 
please call the contact listed above.

FOR FURTHER INFORMATION CONTACT: Craig Cockrell, 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

[[Page 2585]]

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 or, if the taking 
is limited to harassment, a notice of a issued 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 mitigation, 
monitoring and reporting of the takings are set forth. The definitions 
of all applicable MMPA statutory terms cited above are included in the 
relevant sections below.

Summary of Request

    On September 13, 2022, NMFS received a request from ADOT&PF for an 
IHA to take marine mammals incidental to vibratory and impact pile 
driving to improve the Auke Bay East Ferry Terminal. Following NMFS' 
review of the application, ADOT&PF submitted a revised version on 
January 11, 2023. The application was deemed adequate and complete on 
February 14, 2023. NMFS published the proposed IHA on April 13, 2023 
(88 FR 22411). The ADOT&PF's request is for the incidental take of 
small numbers of 11 species or stocks of marine mammals, in the form of 
Level B harassment and, for harbor seals (Phoca vitulina) and harbor 
porpoise (Phocoena phocoena), including take by Level A harassment. 
Neither ADOT&PF nor NMFS expect serious injury or mortality to result 
from this activity and, therefore, an IHA is appropriate.

Description of Activity

Overview

    ADOT&PF is completing improvements to the existing Alaska Marine 
Highway System (AMHS) Auke Bay East Berth marine terminal. The activity 
includes removal of existing piles and the installation of both 
temporary and permanent piles of various sizes and materials. A total 
of 143 piles will be either removed or installed. Takes of marine 
mammals by Level A and Level B harassment will occur due to both impact 
installation and vibratory pile installation and removal. The project 
will occur in Auke Bay, Alaska which is located in southeast Alaska in 
close proximity to the city of Juneau. Construction activities are 
expected to over a four month period in fall 2023. It is expected to 
take up to 61 nonconsecutive days to complete the in-water pile driving 
activities.
    A detailed description of the planned construction project is 
provided in the Federal Register notice for the proposed IHA (88 FR 
22411, April 13, 2023). 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 Response

    A notice of NMFS' proposal to issue an IHA to ADOT&PF was published 
in the Federal Register on April 13, 2023 (88 FR 22411). That notice 
described, in detail, ADOT&PF's activities, the marine mammal species 
that may be affected by the activities, 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. This proposed notice was available for a 30-
day public comment period.
    NMFS received one comment from the general public. This comment was 
not related to the activity described in the notice and is not 
discussed further.

Changes From Proposed IHA to Final IHA

    Several changes have been made to the Final IHA. These changes are 
summarized below and also identified, and expanded upon as necessary, 
in the associated sections of the notice below. In the Proposed IHA the 
extent of the Level B harassment zone for vibratory installation and 
removal of 24 in. steel piles was inadvertently combined with 18 in. 
steel pipe piles. Table 6 has been modified to include the correct size 
of the Level B harassment zone size for the vibratory installation and 
removal of 24 in. steel piles. The Level A and Level B harassment zones 
for 18 in. steel pipe piles were not calculated correctly in the 
Proposed IHA. Table 6 has been updated, and Level A and Level B 
harassment zones for vibratory installation and removal of the existing 
18 in. steel pipe piles have been corrected.
    As a result of our consultation under Section 7 of the ESA with the 
NMFS Alaska Regional Office, NMFS has revised the source levels for 
vibratory driving of 24 in. and 30 inch steel piles. In the Proposed 
IHA, 159 and 154 dB RMS re 1[micro]Pa were the selected source values 
for 30 in. and 24 in. steel pipe pile driving, respectively (Caltrans 
2020). During the comment period for the Proposed IHA, NFMS determined 
that measured values from a previous project in Auke Bay and other 
sites with similar geology were more appropriate than the proposed 
values. Based on this information NMFS has revised our analysis to use 
source proxy values of 168.8 from Denes et al. (2016) and 163 dB RMS re 
1[micro]Pa (NMFS 2023 analysis \1\) for vibratory driving of 30 in. and 
24 in. steel pipe piles, respectively. Denes et al. (2016) measured a 
spreading loss coefficient (TL) of 16.4 for 30 in. piles, which NMFS 
has applied in the harassment zone calculations. These values increase 
the size of the harassment zones, shutdown zones, and monitoring zones 
for this project (table 6, 8, and 9). Due to the larger estimated 
harassment zones, NMFS has increased the level of take by Level B 
harassment for some marine mammal species (table 7). No increase in 
Level A take occurred based on this new analysis because the ADOT&PF 
has agreed to implement shut down zones larger than the expected Level 
A harassment zones. The larger shutdown and monitoring zones do not 
require any changes to the other subsequent mitigation, monitoring, or 
reporting measures from Proposed IHA, and thus there have been no 
changes to the mitigation, monitoring, and reporting sections in this 
Notice.
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    \1\ Averaged values from Navy (2012, 2013) and Miner (2020).
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    Since the Federal Register notice of the proposed IHA was published 
(April 13, 2023, 88 FR 22411), NMFS published the final 2022 Alaska and 
Pacific Stock Assessment Reports (SARs), which describe revised stock 
structures under the MMPA for humpback whales and southeast Alaska 
harbor porpoise (Carretta et al., 2023; Young et al., 2023). In the 
notice of proposed IHA, we explained that although we typically 
consider updated peer-reviewed data provided in draft SARs to be the 
best available science, and use the information accordingly, we make 
exception for proposed revised stock structures. Upon finalization of 
these revised stock structures, we have

[[Page 2586]]

made appropriate updates, including description of the potentially 
affected stocks (see table 1), attribution of take numbers to stock 
(see Estimated Take), and by updating our analyses to ensure the 
necessary determinations are made for the new stocks (see Negligible 
Impact Analysis and Determination and Small Numbers).
    There was also a clerical error in the calculation of the 
percentage of humpback whales from each respective DPS. The Proposed 
IHA used 2.4 percent as the estimated percentage of Mexico DPS humpback 
whales present in Southeast Alaska. This was revised to 2 percent in 
this notice and the numbers of take from each DPS were revised 
accordingly (see Estimated Take).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the IHA 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, incorporated here by reference, 
instead of reprinting the information. Additional information regarding 
population trends and threats may be found in NMFS' SARs; 
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).
    All values presented in table 1 are the most recent available at 
the time of publication (including from the draft 2022 SARs) and are 
available online at: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments).

                                              Table 1--Species Likely Impacted by the Specified Activities
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                                                                                         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\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae (rorquals):
    Humpback whale..................  Megaptera novaeangliae.  Hawai[revaps]i.........  -, -, N             11,278 (0.56, 7,265,          127      27.09
                                                                                                             2020).
                                                               Mexico-North Pacific...  T, D, Y             918 (0.217, UNK, 2006)        UND       0.57
    Minke whale.....................  Balaenoptera             Alaska.................  -/-; N              N/A (N/A, N/A, N/A)...        UND          0
                                       acutorostrada.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Killer whale....................  Orcinus orca...........  Alaska Resident........  -/-; N              1,920 (N/A, 1,920,             19        1.3
                                                                                                             2019).
                                                               West Coast Transient...  -/-; N              349 (N/A, 349, 2018)..        3.5        0.4
    Pacific white-sided dolphin.....  Lagenorhynchus           North Pacific..........  -/-; N              26,880 (N/A, N/A,             UND          0
                                       obliquidens.                                                          1990).
Family Phocoenidae (porpoises):
    Harbor Porpoise.................  Phocoena phocoena......  Northern Southeast       -, -, N             1,619 (0.26, 1,250,            13        5.6
                                                                Alaska Inland Waters.                        2019).
    Dall's porpoise.................  Phocoenoides dalli.....  Alaska.................  -/-; N              UND (UND, UND, 2015)..        UND         37
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
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Family Otariidae (eared seals and
 sea lions):
    Steller sea lion................  Eumetopias jubatus.....  Eastern DPS............  -/-; N              43,201 (N/A, 43,201,        2,592        112
                                                                                                             2017).
                                                               Western DPS............  E/D; Y              52,932 (N/A, 53,932,          318        254
                                                                                                             2019).
    California sea lion.............  Zalophus californianus.  U.S....................  -/-; N              257,606 (N/A, 233,515,     14,011       >321
                                                                                                             2014).
    Northern fur seal...............  Callorhinus ursinus....  Eastern Pacific........  -/-; Y              626,618 (0.2, 530,376,     11,403        373
                                                                                                             2019).
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulina.........  Lynn Canal/Stephens      -/-; N              13,388 (N/A, 11,867,          214         50
                                                                Passage.                                     2016).
    Northern Elephant Seal..........  Mirounga angustirostris  California.............  -/-; N              187,386 (N/A, 85,369,       5,122       13.7
                                                                                                             2013).
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds 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 stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
  stock abundance. In some cases, CV is not applicable.
\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. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.

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

[[Page 2587]]

(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 (baleen   7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans           150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true    275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 Cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater)     50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)    60 Hz to 39 kHz.
 (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 and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    The effects of underwater noise from ADOT&PF's construction 
activities have the potential to result in behavioral harassment of 
marine mammals in the vicinity of the survey area. The notice of 
proposed IHA (88 FR 22411, April 13, 2023) included a discussion of the 
effects of anthropogenic noise on marine mammals and the potential 
effects of underwater noise from ADOT&PF's on marine mammals and their 
habitat. That information and analysis is incorporated by reference 
into this final IHA determination and is not repeated here; please 
refer to the notice of proposed IHA (88 FR 22411, April 13, 2023).

Estimated Take

    This section provides an estimate of the number of incidental takes 
for the authorization through this IHA, 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. Authorized takes will primarily be by Level B harassment, 
as use of the acoustic sources (i.e., impact and vibratory pile 
driving) 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 high 
frequency cetaceans and phocids because predicted auditory injury zones 
are larger than for other hearing groups. Auditory injury is unlikely 
to occur for other groups. The mitigation and monitoring measures are 
expected to minimize the severity of the taking to the extent 
practicable.
    As described in the proposed notice (88 FR 22411, April 13, 2023), 
no serious injury or mortality is anticipated or authorized for this 
activity. Below we describe how the take numbers are estimated. As 
noted in the Changes from Proposed IHA to Final IHA section some of the 
harassment and monitoring zones have changed as well as the estimated 
take number for some marine mammal species.
    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 
will 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

[[Page 2588]]

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 (root mean square (RMS) sound 
pressure level (SPL)) of 120 dB (referenced to 1 micropascal (re 1 
microPascal ([mu]Pa)) for continuous (e.g., vibratory pile-driving) and 
above RMS SPL 160 dB re 1 [mu]Pa for non-explosive impulsive (e.g., 
seismic airguns, impact pile driving) 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 shifts (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 will not otherwise occur.
    ADOT&PF's activity includes the use of continuous (vibratory pile 
installation and removal) and impulsive (impact pile driving) sources, 
and therefore the RMS SPL thresholds of 120 and 160 dB re 1 [mu]Pa are 
applicable.
    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). ADOT&PF's 
activity includes the use of impulsive (impact pile driving) 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: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                                Table 3--Onset of Permanent Threshold Shift (PTS)
                                                   [NMFS 2018]
----------------------------------------------------------------------------------------------------------------
                                                         PTS onset thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: L0-pk,flat: 219     Cell 2: LE, LF,24h: 199 dB.
                                          dB; LE, LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: L0-pk,flat: 230     Cell 4: LE, MF,24h: 198 dB.
                                          dB; LE,  MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: L0-pk,flat: 202     Cell 6: LE, HF,24h: 173 dB.
                                          dB; LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: L0-pk.flat: 218     Cell 8: LE,PW,24h: 201 dB.
                                          dB; LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: L0-pk,flat: 232     Cell 10: LE,OW,24h: 219 dB.
                                          dB; LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric 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 are recommended for consideration.
Note: Peak sound pressure level (L0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
  exposure level (LE,) has a reference value of 1[micro]Pa\2\s. In this table, thresholds are abbreviated to be
  more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
  is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
  hearing range of marine mammals (i.e., 7 Hz to 160 kHz). The subscript associated with cumulative sound
  exposure level 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 weighted
  cumulative sound exposure level 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 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 
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., impact pile driving, vibratory pile 
driving and removal). The maximum (underwater) area ensonified above 
the thresholds for behavioral harassment referenced above is 30.7 km\2\ 
(11.9 mi\2\), and is governed by the topography of Auke Bay and the 
various islands located within and around the bay. This underwater area 
has increased from the proposed IHA due to the higher source level for 
30 inch piles (168.8 dB RMS re 1[micro]Pa) anticipated in Auke Bay. The 
eastern part of Auke Bay is acoustically shadowed by Auke Cape, Coghlan 
Island, and Suedla Island, and will inhibit sound transmission from 
reaching the more open waters toward Spuhn Island (see Figure 6-2 in 
the IHA application). Additionally, vessel traffic and other commercial 
and industrial activities in the project area may contribute to 
elevated background noise levels which may mask sounds produced by the 
project.
    Transmission loss (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 * Log<INF>10</INF> (R<INF>1</INF>/R<INF>2</INF>),

where:

TL = transmission loss in dB
B = transmission loss coefficient
R<INF>1</INF> = the distance of the modeled SPL from the driven 
pile, and
R<INF>2</INF> = the distance from the driven pile of the initial 
measurement

    This formula neglects loss due to scattering and absorption, which 
is assumed to be zero here. The degree to which underwater sound 
propagates away from a sound source is dependent on a variety of 
factors, most notably the water bathymetry and presence or absence of 
reflective or absorptive

[[Page 2589]]

conditions including in-water structures and sediments. Spherical 
spreading occurs in a perfectly unobstructed (free-field) environment 
not limited by depth or water surface, resulting in a 6 dB reduction in 
sound level for each doubling of distance from the source 
(20*log<INF>10</INF>[range]). Cylindrical spreading occurs in an 
environment in which sound propagation is bounded by the water surface 
and sea bottom, resulting in a reduction of 3 dB in sound level for 
each doubling of distance from the source (10*log<INF>10</INF>[range]). 
A practical spreading value of 15 is often used under conditions, such 
as the project site, where water increases with depth as the receiver 
moves away from the shoreline, resulting in an expected propagation 
environment that will lie between spherical and cylindrical spreading 
loss conditions. Transmission loss can be measured in the field for 
specific sites and activities.
    Since the proposed IHA was published, NMFS identified site-specific 
spreading loss data that are applicable to Auke Bay. Specifically, 
Denes et al. (2016) measured a spreading loss coefficient of 16.4 
during the previous monitoring of vibratory installation of 30-in steel 
pipe piles in Auke Bay. This value is applicable for the current 
analysis, and we have therefore used TL = 16.4 for determining the 
harassment zones for vibratory installation of 30 inch steel pipe 
piles. For all other planned pile types and driving methods, there are 
no available site-specific TL measurements. NMFS has therefore used the 
default practical spreading model (TL = 15) in analysis of all other 
pile types for this project.
    The intensity of pile driving sounds is greatly influenced by 
factors such as the type of piles, hammers, and the physical 
environment in which the activity takes place. In order to calculate 
the distances to the Level A harassment and the Level B harassment 
thresholds for the methods and piles being used in this project, NMFS 
used acoustic monitoring data from other locations to develop proxy 
source levels for the various pile types, sizes and methods. The 
project includes vibratory and impact pile installation and vibratory 
removal of steel pipe piles. Proxy source levels for each pile size and 
driving method are presented in table 4. The source levels for 
vibratory and impact installation of all pile sizes are based on 
measured values from similar types of piles reported in the following 
sources: California Department of Transportation (Caltrans) in pile 
driving source level compendium documents (Caltrans, 2015 and 2020); 
Denes et al. (2016), and mean values for other regionally relevant 
reports compiled by NMFS (table 4).

                                          Table 4--Proxy Sound Source Levels for Pile Sizes and Driving Methods
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                     Proxy source level
                                                                 ---------------------------------------------------------
               Pile size                         Method               dB RMS re          dB SEL re          dB peak re           Literature source
                                                                      1[micro]Pa      1[micro]Pa\2\sec      1[micro]Pa
--------------------------------------------------------------------------------------------------------------------------------------------------------
30 in.................................  Vibratory...............            * 168.8                N/A                N/A  Denes et al. 2016.
24 in.................................  Vibratory...............              * 163                N/A                N/A  NMFS 2023 analysis.**
18 in.................................  Vibratory...............                158                N/A                N/A  Caltrans 2020.
30 in.................................  Impact..................                190                177                210  Caltrans 2015, 2020.
24 in.................................  Impact..................                190                177                203  Caltrans 2015, 2020.
18 in.................................  Impact..................                185                175                200  Caltrans 2015, 2020.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Source levels for vibratory pile installation and removal from the proposed IHA for 30 in. and 24 in. piles were 159 dB RMS re 1[micro]Pa and 154 dB
  RMS re 1[micro]Pa respectively.
** Navy (2012, 2013) and Miner (2020); averaging methodology followed Navy (2015).

    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 going to be 
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 impact or vibratory pile driving and 
removal, 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 will be expected to incur PTS. Inputs used in the 
optional User Spreadsheet tool (table 5), and the resulting estimated 
isopleths and the calculated Level B harassment isopleth (table 6), are 
reported below. For source levels of each pile please refer to table 4.
    For impact installation of piles, the harassment zones were 
calculated based on the number of piles to be installed per day. 
ADOT&PF provided a range of one to four piles per day for impact 
installation for all pile sizes. This was done to account for more 
efficient days of pile installation as not to limit construction 
activity on those days. If more piles per day are installed it is 
likely to reduce the number of days impact installation will occur.

[[Page 2590]]



          Table 5--User Spreadsheet Input Parameters Used for Calculating Level A Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
                                                     Weighting
  Pile size and installation     Spreadsheet tab      factor         Number of       Number of       Activity
            method                    used          adjustment      strikes per    piles per day     duration
                                                       (kHz)           pile                          (minutes)
----------------------------------------------------------------------------------------------------------------
30 in vibratory installation..  A.1 Vibratory                2.5             N/A               3              60
                                 pile driving.
24 in vibratory installation..  A.1 Vibratory                2.5             N/A               3              60
                                 pile driving.
24 in vibratory installation    A.1 Vibratory                2.5             N/A               3              30
 (temporary).                    pile driving.
24 in vibratory removal         A.1 Vibratory                2.5             N/A               3              60
 (temporary).                    pile driving.
18 in vibratory installation..  A.1 Vibratory                2.5             N/A               3              60
                                 pile driving.
18 in vibratory removal         A.1 Vibratory                2.5             N/A               3              30
 (existing).                     pile driving.
30 in impact installation.....  E.1 Impact pile                2           1,000             1-4             N/A
                                 driving.
24 in impact installation.....  E.1 Impact pile                2           1,000             1-4             N/A
                                 driving.
24 in impact installation.....  E.1 Impact pile                2             500             1-4             N/A
                                 driving.
18 in impact installation.....  E.1 Impact pile                2             800             1-4             N/A
                                 driving.
----------------------------------------------------------------------------------------------------------------


                                              Table 6--Calculated Level A and Level B Harassment Isopleths
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                   Level A harassment zone  (m)                               Level B
                        Activity                         --------------------------------------------------------------------------------   harassment
                                                           LF-cetaceans    MF-cetaceans    HF-cetaceans       Phocids        Otariids        zone  (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
30 in vibratory installation............................         41 (11)           5 (1)         59 (16)          26 (7)           2 (1)         * 9,454
24 in vibratory installation............................          19 (5)           2 (1)          29 (8)          12 (3)           1 (1)         * 7,356
24 in vibratory installation (temporary)................          12 (4)           1 (1)          18 (5)           7 (2)           1 (1)
24 in vibratory removal (temporary).....................          19 (5)           2 (1)          29 (8)          12 (3)           1 (1)
18 in vibratory installation............................               9               1              14               6               1         * 3,415
18 in vibratory removal (existing)......................           6 (9)           1 (1)          8 (14)           3 (6)           1 (1)
30 in impact installation (4 piles per day; 1,000                  1,002              36           1,194             537              39           1,000
 strikes per pile)......................................
30 in impact installation (3 piles per day; 1,000                    827              30             985             443              33
 strikes per pile)......................................
30 in impact installation (2 piles per day; 1,000                    632              23             752             338              25
 strikes per pile)......................................
30 in impact installation (1 pile per day; 1,000 strikes             398              15             474             213              16
 per pile)..............................................
24 in impact installation (4 piles per day; 1,000                  1,002              36           1,194             537              39           1,000
 strikes per pile)......................................
24 in impact installation (3 piles per day; 1,000                    827              30             985             443              33
 strikes per pile)......................................
24 in impact installation (2 piles per day; 1,000                    632              23             752             338              25
 strikes per pile)......................................
24 in impact installation (1 pile per day; 1,000 strikes             398              15             474             213              16
 per pile)..............................................
24 in impact installation (4 piles per day; 500 strikes              632              23             752             338              25
 per pile)..............................................
24 in impact installation (3 piles per day; 500 strikes              521              19             621             279              21
 per pile)..............................................
24 in impact installation (2 piles per day; 500 strikes              398              15             474             213              16
 per pile)..............................................
24 in impact installation (1 pile per day; 500 strikes               251               9             299             134              10
 per pile)..............................................
18 in impact installation (4 piles per day; 800 strikes              636              23             757             340              25             464
 per pile)..............................................
18 in impact installation (3 piles per day; 800 strikes              525              19             625             281              21
 per pile)..............................................
18 in impact installation (2 piles per day; 800 strikes              401              15             477             215              16
 per pile)..............................................
18 in impact installation (1 pile per day; 800 strikes               252               9             301             135              10
 per pile)..............................................
--------------------------------------------------------------------------------------------------------------------------------------------------------
* The Proposed IHA ((88 FR 22411, April 13, 2023) harassment zones for vibratory installation and removal for 30 in., 24 in., and 18 in. steel pipe
  piles were 3,981, 1,848, and 1,848 respectively.

Marine Mammal Occurrence and Take Estimation

    In this section, we provide information about the occurrence of 
marine mammals, including density or other relevant information that 
will inform the take calculations. As described above, since the 
proposed IHA, changes have been made to some of the harassment zones. 
These changes have resulted in changes to the amount of Level B 
harassment authorized for all species, with the exception of the four 
species that are rarely encountered (minke whales, California sea 
lions, Northern fur seals, and Northern elephant seals). The changes 
are

[[Page 2591]]

described in the sections below and reflected in table 7.
    When available, peer-reviewed scientific publications were used to 
estimate marine mammal abundance in the project area. Data from 
monitoring reports from previous projects on the Auke Bay Ferry 
Terminal were used as well as reports from other projects in Juneau, 
Alaska. However, scientific surveys and resulting data, such as 
population estimates, densities, and other quantitative information, 
are lacking for some marine mammal populations and most areas of 
southeast Alaska, including Auke Bay. Therefore, AKDOT&PF gathered 
qualitative information from discussions with knowledgeable local 
people in the Auke Bay area.
    Here we describe how the information provided is synthesized to 
produce a quantitative estimate of the take that is reasonably likely 
to occur and authorized for authorization. Since reliable densities are 
not available, the applicant requests take based on the maximum number 
of animals that may occur in the harbor in a specified measure of time 
multiplied by the total duration of the activity.

Humpback Whale

    Use of Auke Bay by humpback whales is intermittent and irregular 
year-round. During winter, researchers have documented 1 to 19 
individual humpback whales per month in waters close to the project 
area, including Lynn Canal (Moran et al., 2018a; Straley et al., 2018). 
Group sizes in southeast Alaska generally range from one to four 
individuals (Dahlheim et al., 2009). In the Proposed IHA NMFS predicted 
that two groups of two humpback whales could be exposed to Level B 
harassment during each day of the 61 days of work for a total of 244 
animals. After revising the Level B harassment zones for 30 inch and 24 
inch steel pipe piles, NMFS noted that the entrance to Fritz Cove is 
part of the new ensonified area during vibratory driving of 24-in and 
30-in. piles. During winter, Fritz Cove is a known aggregation area for 
humpback whales. Thus, NMFS expects that an additional two groups of 
two could occur during pile driving activities for a total of 488 
animals (Wright, S., pers. comm.). As described previously, 2 percent 
of the humpback whales in Southeast Alaska are members of the Mexico 
distinct population segment (DPS), and therefore 10 animals will be 
Mexico DPS individuals and the remaining 478 animals will be Hawaii DPS 
individuals.
    The largest Level A shutdown zone for humpback whales extends 1,002 
meters from the noise source (table 6), and will occur only on days 
when impact driving of four 30 in. or 24 in. piles are expected. All 
construction work will be shut down prior to a humpback whale entering 
the Level A zone specific to the in-water activity underway at the 
time. No take by Level A harassment was requested and none is 
authorized for humpback whales.

Minke Whales

    Dedicated surveys for cetaceans in southeast Alaska found that 
minke whales were scattered throughout inland waters from Glacier Bay 
and Icy Strait to Clarence Strait, with small concentrations near the 
entrance of Glacier Bay. All sightings were of single minke whales, 
except for a single sighting of multiple minke whales. Surveys took 
place in spring, summer, and fall, and minke whales were present in low 
numbers in all seasons and years (Dahlheim et al., 2009). Although 
minke whales are rarely occur in the project area NMFS is authorizing 
take of one minke whale per month by Level B harassment for a total of 
four takes over the course of the project.
    The Level A harassment zones and shutdown protocols for minke 
whales are the same as for humpback whales. Therefore, given the low 
occurrence of minke whales combined with the mitigation, takes by Level 
A harassment have not been requested and are not authorized.

Killer Whale

    Killer whales are observed occasionally during summer throughout 
Lynn Canal, but their presence in Auke Bay is unlikely. In the Proposed 
IHA NMFS expected one killer whale resident pod and one transient pod 
to be taken by Level B harassment. Since the expansion of the new Level 
B harassment zone for vibratory pile driving activities now extends out 
into the open waters of the Stephens Passage, NMFS is authorizing two 
killer whale resident pods and two transient pods to be taken by Level 
B harassment. Group sizes for resident and transient pods are likely to 
be 14 and 44 animals, respectively, which will result in 28 and 88 
animals taken by level B harassment over the course of the project 
(Dahlheim et al., 2009).
    ADOT&PF will implement shutdown zones that encompass the largest 
Level A harassment zones for killer whales during all pile driving 
activities. Killer whales are generally conspicuous and protected 
species observers (PSOs) are expected to detect killer whales and 
implement a shutdown before the animals enter the Level A harassment 
zone. Therefore, takes by Level A harassment have not been requested 
and are not authorized.

Pacific White-Sided Dolphins

    Based on occurrence data ADOT&PF requested a total of 92 takes by 
Level B harassment (the median group size observed in aerial surveys; 
range from 20 to 164 individuals) (Muto et al. 2022). NMFS proposed 
this take level by Level B harassment based on one group of Pacific 
white-sided dolphins to occur over the duration of the project. Similar 
to killer whales, NMFS is authorizing higher take levels of Pacific 
white-sided dolphins by Level B harassment due to the larger harassment 
zone. NMFS expects two groups of 92 to occur during construction 
activities resulting in a total of 184 takes by Level B harassment.
    The largest Level A harassment zone for Pacific white-sided 
dolphins extends 36 m from the source during impact installation of 30-
in piles (table 6). Pacific white-sided dolphins are expected to be 
seen by PSOs before entering this zone and shutdown of activity will 
occur. No take by Level A harassment is authorized or anticipated.

Harbor Porpoise

    Initially ADOT&PF requested a total of 122 takes of harbor porpoise 
over the course of the 61 day project. ADOT&PF estimated that 25 
percent of those takes could be Level A exposures which would equate to 
30 over the project duration. After further review of previous 
monitoring results, including unpublished data (Wright, S., pers. 
comm.), NMFS proposed authorization of four animals per day in the 
Proposed IHA, equating to 244 takes of harbor porpoise by Level A and 
Level B harassment.
    Given the larger Level B harassment zone, NMFS now expects an 
additional 56 takes by Level B harassment. This was calculated by 
doubling the estimated abundance of this species for the 14 days of 
vibratory driving of 30 inch piles. NMFS determined that increasing the 
take in proportion to the increased area ensonified was not justified 
because harbor porpoise tend to inhabit coastal shallow water and the 
new harassment zone does not encompass a substantial amount of new 
shoreline compared to the initial proposed harassment zone. The total 
number of takes by Level B harassment authorized is 300. NMFS has not 
increased the authorized takes by Level A harassment because the 
increases in Level A harassment zones expected during vibratory driving 
of 24-in and 30-in steel pipe piles are minimal and the

[[Page 2592]]

applicant has agreed to increase the size of the shutdown zone for this 
species during these activities to encompass the increased Level A 
isopleths.
    Harbor porpoises are known to be an inconspicuous species and are 
challenging for protected species observers (PSOs) to sight, making any 
approach to a specific area potentially difficult to detect. Because 
harbor porpoises move quickly and elusively, it is possible that they 
may enter the Level A harassment zone without detection. The largest 
Level A harassment zone results from impact driving of 30-in piles, and 
extends 1,194 m from the source for high frequency cetaceans (table 6). 
ADOT&PF will implement a shutdown zone for harbor porpoises that 
encompasses the largest Level A harassment zone (see Mitigation 
section) but given the sighting challenges for PSOs some take by Level 
A harassment is expected during impact pile driving.

Dall's Porpoise

    No systematic studies of Dall's porpoise abundance or distribution 
have occurred in Auke Bay; however, Dall's porpoises have been 
consistently observed in Lynn Canal, Stephens Passage, upper Chatham 
Strait, Frederick Sound, and Clarence Strait (Dalheim et al., 2000). 
ADOT&PF initially requested take of one group of 20 animals per month 
in the project area for a total of 80 takes by Level B harassment. 
After reviewing ADOT&PF's monitoring results from Auke Bay in 2021, one 
lone Dall's porpoise was sighted. Thus, the Proposed IHA included a 
conservative estimate of two groups of five animals per month, giving a 
maximum of 30 takes by Level B harassment throughout the course of the 
project. With the increase in the Level B harassment zones NMFS expects 
one additional group of 5 for a total of 35 takes by Level B 
harassment.
    ADOT&PF will implement shutdown zones for porpoises that encompass 
the largest Level A harassment zones for each pile driving activity 
(see Mitigation section). The largest Level A harassment zone for 
Dall's porpoise extends 1,194 m from the source during impact 
installation of 30-in piles (table 6). Given the more conspicuous 
rooster-tail generated by swimming Dall's porpoises, which makes them 
more noticeable than harbor porpoises, PSOs are expected to detect 
Dall's porpoises prior to them entering the Level A harassment zone 
(Jefferson 2009). Therefore, takes of Dall's porpoises by Level A 
harassment have not been requested and are not authorized.

Steller Sea Lion

    Based on recent monitoring reports for Auke Bay Ferry Terminal and 
Statter Harbor projects (2021 and 2019) it is estimated that groups of 
up to 50 animals per day could be exposed to underwater noise. The 
Proposed IHA predicted a total of 3,050 exposures to sound levels at or 
above the Level B harassment threshold could occur over the 61 days of 
construction. Steller sea lions have similar habitat usage pattern as 
humpback whales in Fritz Cove. Therefore, NMFS is increasing the number 
of takes to 6,100. Given the 1.4 percent of Steller sea lions belong to 
the western DPS (wDPS) in Auke Bay, 86 total exposures are expected 
from the wDPS and the remaining 6,015 exposures of eastern DPS Steller 
sea lions.
    The largest Level A harassment zone for otariid pinnipeds extends 
39 m from the source (table 6). ADOT&PF is planning to implement a 
larger shutdown zones than the Level A harassment zones during all pile 
installation and removal activities (see Mitigation section), which is 
expected to eliminate the potential for take by Level A harassment of 
Steller sea lions. Therefore, no takes of Steller sea lions by Level A 
harassment were requested or are authorized.

California Sea Lion

    California sea lions rarely occur in the project area. In 2017, a 
lone California sea lion was spotted in the harbor. Recently, 
monitoring reports from similar construction projects did not observe 
any California sea lions in Auke Bay. Based on the sighting from 2017, 
ADOT&PF is estimating one animal per day of construction which will 
equate to 61 takes by Level B harassment.
    The largest Level A harassment zone for otariid pinnipeds extends 
39 m from the source (table 6). ADOT&PF is planning to implement larger 
shutdown zones than the Level A harassment zones during all pile 
installation and removal activities (see Mitigation section), which is 
expected to eliminate the potential for take by Level A harassment of 
California sea lions. Therefore, no takes of California sea lions by 
Level A harassment were requested or are authorized.

Northern Fur Seal

    Although take of Northern fur seal was not requested by ADOT&PF, 
NMFS recommended the inclusion of Northern fur seals in the take 
estimation. We estimate that up to five northern fur seals may be 
present in the action area per month which may result in 15 takes by 
Level B harassment over the course of the project.
    The largest Level A harassment zone for otariid pinnipeds extends 
39 m from the source (table 6). ADOT&PF is planning to implement larger 
shutdown zones than the Level A harassment zones during all pile 
installation and removal activities (see Mitigation section), which is 
expected to eliminate the potential for take by Level A harassment of 
Northern fur seals. Therefore, no takes of Northern fur seals by Level 
A harassment were requested or are authorized.

Harbor Seal

    In the Proposed IHA, NMFS based take estimates on the monitoring 
results of ADOT&PF's 2021 project in Auke Bay. It was expected that 50 
harbor seals per day could be taken during the 61 days of construction 
(AKDOT&PF, 2021). NMFS proposed 3,050 takes of harbor seals by Level B 
harassment for the duration of the project. Similar to harbor porpoise, 
harbor seals typically inhabit costal inland waters. Given the larger 
Level B harassment zones NMFS expects, an additional 447 takes by Level 
B harassment over the 14 day of vibratory installation of 30-in piles 
are estimated. NMFS is authorizing 3,752 takes by Level B harassment 
for the duration of the project. NMFS has not increased the authorized 
takes by Level A harassment because the increases in Level A harassment 
zones expected during vibratory driving of 24-in and 30-in steel pipe 
piles are minimal and the applicant has agreed to increase the size of 
the shutdown zones for this species during these activities to 
encompass the increased Level A isopleths.
    The largest Level A harassment zone for phocid pinnipeds results 
from impact pile driving of 30-in piles and extends 537 m from the 
source (table 6). There are no haulouts located within the Level A 
harassment zone and although it is unlikely, it is possible that harbor 
seals may approach and enter the Level A harassment zone undetected. 
Two harbor seals are estimated to approach the site within 537 m of the 
source each day. Impact pile driving may occur on up to 34 days (table 
1). For this reason, we propose take by Level A harassment of two 
harbor seals daily on the 34 days of impact pile driving for a total of 
68 takes by Level A harassment. The largest Level A harassment zone for 
phocid pinnipeds from vibratory pile driving extends 30 m from the 
source (table 6). ADOT&PF is planning to implement larger shutdown 
zones than the Level A harassment zones during all pile installation 
and removal activities (see Mitigation

[[Page 2593]]

section), which is expected to eliminate the potential for Level A 
harassment of harbor seals from vibratory pile driving.

Northern Elephant Seal

    Given the increase in population size and sightings throughout 
Southeast Alaska ADOT&PF requested one elephant seal take per week. The 
project is expected to take up to 16 weeks to complete which will 
equate to 16 takes by Level B harassment.
    The largest Level A harassment zone for phocid pinnipeds extends 
537 m from the source (table 6). ADOT&PF is planning to implement 
larger shutdown zones than the Level A harassment zones during all pile 
installation and removal activities (see Mitigation section), which is 
expected to eliminate the potential for take by Level A harassment of 
elephant seals. Therefore, no takes of elephant seals by Level A 
harassment were requested or are authorized.

                                    Table 7--Authorized Take by Level A and Level B Harassment, by Species and Stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        Proposed IHA               Final IHA authorized take
                                                                              Stock    -----------------------------------------------------------------
                Common name                             Stock               abundance       Total                                              Take as
                                                                               \a\        proposed      Level A      Level B     Total take   percentage
                                                                                            take       harassment   harassment                 of stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale............................  Hawai[revaps]i...............       11,278           238            0          476          476          4.2
                                            Mexico-North Pacific.........          918             6            0           10           10          1.1
Minke whale...............................  Alaska.......................          N/A             4            0            4            4          N/A
Killer Whale..............................  Alaska Resident..............        1,920            41            0           82           82          4.3
                                            West Coast Transient.........          349            14            0           28           28          8.0
Pacific white-sided dolphin...............  North Pacific................      931,000            92            0          184          184         0.02
Harbor porpoise...........................  Northern Southeast Alaska....        1,619           244           61          300          361         22.3
Dall's porpoise...........................  Alaska.......................       83,400            30            0           35           35         0.04
Steller sea lion..........................  Eastern U.S..................       43,201         3,008            0        6,015        6,015         13.9
                                            Western U.S..................       52,932            43            0           86           86         0.16
California sea lion.......................  U.S..........................      257,606            61            0           61           61         0.02
Northern fur seal.........................  Eastern Pacific..............      626,618            15            0           15           15        <0.01
Harbor seal...............................  Lynn Canal/Stephens Passage..       13,388         3,050           68        3,752        3,820         28.5
Northern Elephant Seal....................  California...................      187,386            16            0           16           16        <0.01
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Stock or DPS size is Nbest according to NMFS 2022 Final Stock Assessment Reports.

Mitigation Measures

    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. 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, impact on 
operations.
    In addition to the measures described later in this section, 
ADOT&PF will employ the following standard mitigation measures:
    <bullet> At the start of each day, the Contractor(s) will hold a 
briefing with the Lead PSO to outline the activities planned for that 
day.
    <bullet> If poor weather conditions restrict the PSO's ability to 
make observations within the Level A and B harassment zone of pile 
driving (e.g., if there is excessive wind or fog), pile installation 
and removal will be halted.
    The following measures will apply to ADOT&PF's mitigation 
requirements:
    Implementation of Shutdown Zones for Level A Harassment--For all 
pile driving/removal activities, ADOT&PF will implement shutdowns 
within designated zones. The purpose of a shutdown zone is generally to 
define an area within which shutdown of activity will occur upon 
sighting of a marine mammal (or in anticipation of an animal entering 
the defined area). Implementation of shutdowns will be used to avoid or 
minimize incidental Level A harassment exposures from vibratory and 
impact pile driving for all 11 species for which take may occur (see 
table 7). ADOT&PF has voluntarily implemented a minimum shutdown zone 
of 30 m during all pile driving and removal activities (table 8). 
Shutdown zones for impact pile driving activities are based on the 
Level A harassment zones and therefore vary by pile size, number of 
piles installed per day, and marine mammal hearing group (table 8). 
Shutdown zones for impact pile driving will be established each day for 
the greatest number of piles that are expected to be installed that 
day. The placement of PSOs during all pile driving activities 
(described in detail in the Monitoring and Reporting Section) will 
ensure the full extent of shutdown zones are visible to PSOs.

[[Page 2594]]



                          Table 8--Shutdown Zones During Pile Installation and Removal
----------------------------------------------------------------------------------------------------------------
                                                                        Shutdown zones (m)
                                     Piles per  ----------------------------------------------------------------
             Activity                  day *          LF           MF           HF
                                                  cetaceans    cetaceans    cetaceans     Phocids      Otariids
----------------------------------------------------------------------------------------------------------------
All vibratory installation and              N/A        ** 75           30        ** 75           30           30
 removal..........................
30-in impact (1,000 strikes)......            4        1,100           40        1,200          540           40
                                              3          830           30          990          450
                                              2          640                       760          340           30
                                              1          400                       480          220
24-in impact (1,000 strikes)......            4        1,100           40        1,200          540           40
                                              3          830           30          990          450
                                              2          640                       760          340           30
                                              1          400                       480          220
24-in impact (500 strikes)........            4          640           30          760          340           30
                                              3          530                       630          280
                                              2          400                       480          220
                                              1          260                       300          140
18-in impact (800 strikes)........            4          640           30          760          340           30
                                              3          530                       630          280
                                              2          400                       480          220
                                              1          260                       300          140
----------------------------------------------------------------------------------------------------------------
* The applicant will chose the number of piles to be driven in any given day (and therefore the maximum
  associated shutdown zone to be implemented that day) before work begins. Shutdown zones may not change for a
  given day once implemented.
** Zones that have increased from the Proposed IHA (88 FR 22411, April 13, 2023).

    Establishment of Monitoring Zones--ADOT&PF has identified 
monitoring zones correlated with the larger of the Level B harassment 
or Level A harassment zones. Monitoring zones provide utility for 
observing by establishing monitoring protocols for areas adjacent to 
the shutdown zones. Monitoring zones enable observers to be aware of 
and communicate the presence of marine mammals in the project area 
outside the shutdown zone and thus prepare for a potential cease of 
activity should the animal enter the shutdown zone. PSOs will monitor 
the entire visible area to maintain the best sense of where animals are 
moving relative to the zone boundaries defined in tables 8 and 9. 
Placement of PSOs on the shorelines around Auke Bay allow PSOs to 
observe marine mammals within and near Auke Bay.

                 Table 9--Marine Mammal Monitoring Zone
------------------------------------------------------------------------
                                                            Monitoring
                        Activity                             zone (m)
------------------------------------------------------------------------
30-in vibratory installation............................         * 9,454
24-in 18-in vibratory installation and removal..........         * 7,356
18-in vibratory installation and removal................         * 3,415
30-in and 24 in impact installation.....................           1,200
18-in impact installation...............................             760
------------------------------------------------------------------------
* Zones that have increased from the Proposed IHA (88 FR 22411, April
  13, 2023).

    Soft Start--The use of soft-start procedures are believed to 
provide additional protection to marine mammals by providing warning 
and/or giving marine mammals a chance to leave the area prior to the 
hammer operating at full capacity. For impact pile driving, contractors 
will be required to provide an initial set of strikes from the hammer 
at reduced energy, with each strike followed by a 30-second waiting 
period. This procedure will be conducted a total of three times before 
impact pile driving begins. Soft start will be implemented at the start 
of each day's impact pile driving and at any time following cessation 
of impact pile driving for a period of 30 minutes or longer. Soft start 
is not required during vibratory pile driving and removal activities.
    Pre-Activity Monitoring--Prior to the start of daily in-water 
construction activity, or whenever a break in pile driving/removal of 
30 minutes or longer occurs, PSOs will observe the shutdown and 
monitoring zones for a period of 30 minutes. The shutdown zone will be 
considered cleared when a marine mammal has not been observed within 
the zone for that 30-minute period. If a marine mammal is observed 
within the shutdown zone, a soft-start cannot proceed until the animal 
has left the zone or has not been observed for 15 minutes. If the 
monitoring zone has been observed for 30 minutes and marine mammals are 
not present within the zone, soft-start procedures can commence and 
work can continue even if visibility becomes impaired within the 
monitoring zone. When a marine mammal permitted for take by Level B 
harassment is present in the Level B harassment zone, activities may 
begin. No work may begin unless the entire shutdown zone is visible to 
the PSOs. If work ceases for more than 30 minutes, the pre-activity 
monitoring of both the monitoring zone and shutdown zone will commence.
    Based on our evaluation of the applicant's mitigation measures, 
NMFS has determined that the 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:
    <bullet> Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
    <bullet> Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through

[[Page 2595]]

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);
    <bullet> Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
    <bullet> How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
    <bullet> Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
    <bullet> Mitigation and monitoring effectiveness.

Visual Monitoring

    Monitoring shall be conducted by NMFS-approved observers in 
accordance with the monitoring plan and Section 5 of the IHA. Trained 
observers shall be placed from the best vantage point(s) practicable to 
monitor for marine mammals and implement shutdown or delay procedures 
when applicable through communication with the equipment operator. 
Observer training must be provided prior to project start, and shall 
include instruction on species identification (sufficient to 
distinguish the species in the project area), description and 
categorization of observed behaviors and interpretation of behaviors 
that may be construed as being reactions to the specified activity, 
proper completion of data forms, and other basic components of 
biological monitoring, including tracking of observed animals or groups 
of animals such that repeat sound exposures may be attributed to 
individuals (to the extent possible).
    Monitoring will be conducted 30 minutes before, during, and 30 
minutes after pile driving/removal activities. In addition, observers 
shall record all incidents of marine mammal occurrence, regardless of 
distance from activity, and shall document any behavioral reactions in 
concert with distance from piles being driven or removed. Pile driving/
removal 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.
    A minimum of two PSOs will be on duty during all impact 
installation and a minimum of three PSOs during vibratory installation/
removal. Locations from which PSOs will be able to monitor for marine 
mammals are readily available from publicly accessible shoreside areas 
at the Auke Bay East Ferry Terminal and, if necessary, other public and 
private points along the Glacier and Douglas highways. Monitoring 
locations will be selected by the Contractor during pre-construction. 
PSOs will monitor for marine mammals entering the Level B harassment 
zones; the position(s) may vary based on construction activity and 
location of piles or equipment.
    PSOs will scan the waters using binoculars, and/or spotting scopes, 
and will use a handheld range-finder device to verify the distance to 
each sighting from the project site. All PSOs will be trained in marine 
mammal identification and behaviors and are required to have no other 
project-related tasks while conducting monitoring. In addition, 
monitoring will be conducted by qualified observers, who will be placed 
at the best vantage point(s) practicable to monitor for marine mammals 
and implement shutdown/delay procedures when applicable by calling for 
the shutdown to the hammer operator via a radio. ADOT&PF will adhere to 
the following observer qualifications:
    (i) Independent observers (i.e., not construction personnel) are 
required;
    (ii) One PSO will be designated as the lead PSO or monitoring 
coordinator and that observer must have prior experience working as an 
observer;
    (iii) Other observers may substitute education (degree in 
biological science or related field) or training for experience; and
    (iv) ADOT&PF must submit observer Curriculum Vitaes for approval by 
NMFS.
    Additional standard observer qualifications include:
    <bullet> Ability to conduct field observations and collect data 
according to assigned protocols;
    <bullet> Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
    <bullet> Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    <bullet> 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 and times when in-water construction 
activities were suspended to avoid potential incidental injury from 
construction sound of marine mammals observed within a defined shutdown 
zone; and marine mammal behavior; and
    <bullet> 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.

Reporting

    A draft marine mammal monitoring report will be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities. It will include an overall description of work completed, a 
narrative regarding marine mammal sightings, and associated PSO data 
sheets. Specifically, the report must include:
    <bullet> Dates and times (begin and end) of all marine mammal 
monitoring.
    <bullet> Construction activities occurring during each daily 
observation period, including the number and type of piles driven or 
removed and by what method (i.e., impact driving) and the total 
equipment duration for cutting for each pile or total number of strikes 
for each pile (impact driving).
    <bullet> PSO locations during marine mammal monitoring.
    <bullet> 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;
    <bullet> Upon observation of a marine mammal, the following 
information: Name of PSO who sighted the animal(s) and PSO location and 
activity at time of sighting; Time of sighting; 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; Distance and bearing of each 
marine mammal observed relative to the pile being driven for each 
sighting (if pile driving was occurring at time of sighting); Estimated 
number of animals (min/max/best estimate); Estimated number of animals 
by cohort (adults, juveniles, neonates, group composition, etc.); 
Animal's closest point of approach and estimated time spent within the 
harassment zone; 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

[[Page 2596]]

resulted from the activity (e.g., no response or changes in behavioral 
state such as ceasing feeding, changing direction, flushing, or 
breaching);
    <bullet> Number of marine mammals detected within the harassment 
zones, by species.
    <bullet> Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensued, and resulting changes in behavior of the 
animal(s), if any.
    If no comments are received from NMFS within 30 days, the draft 
final report will constitute the final report. If comments are 
received, a final report addressing NMFS comments must be submitted 
within 30 days after receipt of comments.

Reporting Injured or Dead Marine Mammals

    In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA 
(if issued), such as an injury, serious injury or mortality, ADOT&PF 
will immediately cease the specified activities and report the incident 
to the Chief of the Permits and Conservation Division, Office of 
Protected Resources, NMFS, and the Alaska Regional Stranding 
Coordinator. The report will include the following information:
    <bullet> Description of the incident;
    <bullet> Environmental conditions (e.g., Beaufort sea state, 
visibility);
    <bullet> Description of all marine mammal observations in the 24 
hours preceding the incident;
    <bullet> Species identification or description of the animal(s) 
involved;
    <bullet> Fate of the animal(s); and
    <bullet> Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities will not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS will work with ADOT&PF to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. ADOT&PF will not be able to 
resume their activities until notified by NMFS via letter, email, or 
telephone.
    In the event that ADOT&PF discovers an injured or dead marine 
mammal, and the lead PSO determines that the cause of the injury or 
death is unknown and the death is relatively recent (e.g., in less than 
a moderate state of decomposition as described in the next paragraph), 
ADOT&PF will immediately report the incident to the Chief of the 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
and the NMFS Alaska Stranding Hotline and/or by email to the Alaska 
Regional Stranding Coordinator. The report will include the same 
information identified in the paragraph above. Activities will be able 
to continue while NMFS reviews the circumstances of the incident. NMFS 
will work with ADOT&PF to determine whether modifications in the 
activities are appropriate.
    In the event that ADOT&PF discovers an injured or dead marine 
mammal and the lead PSO determines that the injury or death is not 
associated with or related to the activities authorized in the IHA 
(e.g., previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), ADOT&PF will report the incident 
to the Chief of the Permits and Conservation Division, Office of 
Protected Resources, NMFS, and the NMFS Alaska Stranding Hotline and/or 
by email to the Alaska Regional Stranding Coordinator, within 24 hours 
of the discovery. ADOT&PF will provide photographs, video footage (if 
available), or other documentation of the stranded animal sighting to 
NMFS and the Marine Mammal Stranding Network.

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 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 7, 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 and removal activities associated with the project as 
outlined previously, have the potential to disturb or displace marine 
mammals. Specifically, the specified activities may result in take, in 
the form of Level A harassment and Level B harassment from underwater 
sounds generated from pile driving and removal. Potential takes could 
occur if individuals of these species are present in zones ensonified 
above the thresholds for Level A or Level B harassment identified above 
when these activities are underway.
    Take by Level A and Level B harassment will be due to potential 
behavioral disturbance, TTS, and PTS. No serious injury or mortality is 
anticipated or authorized given the nature of the activity and measures 
designed to minimize the possibility of injury to marine mammals. Take 
by Level A harassment is only anticipated for harbor porpoise and 
harbor seal. The potential for harassment is minimized through the 
construction method and the implementation of the mitigation measures 
(see Mitigation section).
    Based on reports in the literature as well as monitoring from other 
similar activities, behavioral disturbance (i.e., Level B harassment) 
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; 
ABR, 2016). Most likely for pile driving, 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 in association with impact pile driving. The pile driving 
activities analyzed here are similar to, or less impactful than, 
numerous other construction activities conducted in southeast Alaska, 
which have taken place with no observed severe responses of any 
individuals or

[[Page 2597]]

known long-term adverse consequences. 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 
associated with the project may produce sound at distances of many 
kilometers from the project site, thus overlapping with some likely 
less-disturbed habitat, the project site itself is located in a busy 
harbor and the majority of sound fields produced by the specified 
activities are close to the harbor. Animals disturbed by project sound 
would be expected to avoid the area and use nearby higher-quality 
habitats.
    In addition to the expected effects resulting from authorized Level 
B harassment, we anticipate that harbor porpoises and harbor seals may 
sustain some limited Level A harassment in the form of auditory injury. 
However, animals in these locations that experience PTS will 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, 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 will 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 
will 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 project also is not expected to have significant adverse 
effects on affected marine mammals' habitat. The project activities 
will not modify existing marine mammal habitat for a significant amount 
of time. The activities may cause some fish or invertebrates 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, the relatively small 
area of the habitat that may be affected, and the availability of 
nearby habitat of similar or higher value, the impacts to marine mammal 
habitat are not expected to cause significant or long-term negative 
consequences.
    Nearly all inland waters of southeast Alaska, including Auke Bay, 
are considered Biological Important Areas (BIA) for feeding at some 
time of the year (Wild et al. 2023), and most are considered ephemeral, 
as humpback whale distribution in southeast Alaska varies by season and 
waterway (Dahlheim et al., 2009). The BIA that overlaps closest to the 
project are active from April through October while the project is 
scheduled to occur between October and March, so overlap with during 
one month of the active BIA is expected. Additionally, pile driving 
associated with the project is expected to take only 61 days, further 
reducing the temporal overlap with the BIA. Therefore, the project is 
not expected to have significant adverse effects on the foraging of 
Alaska humpback whales. No areas of specific biological importance 
(e.g., ESA critical habitat, other BIAs, or other areas) for any other 
species are known to co-occur with the project area.
    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:
    <bullet> No serious injury or mortality is anticipated or 
authorized;
    <bullet> Any Level A harassment exposures (i.e., to harbor 
porpoises and harbor seals, only) are anticipated to result in slight 
PTS (i.e., of a few decibels), within the lower frequencies associated 
with pile driving;
    <bullet> The anticipated incidents of Level B harassment will 
consist of, at worst, temporary modifications in behavior that will not 
result in fitness impacts to individuals;
    <bullet> The area impacted by the specified activity is very small 
relative to the overall habitat ranges of all species, does not include 
ESA-designated critical habitat; and
    <bullet> The mitigation measures are expected to reduce the effects 
of the specified activity to the level of least practicable adverse 
impact.
    In combination, we believe that these factors, as well as the 
available body of evidence from other similar activities, demonstrate 
that the potential effects of the specified activities will have only 
minor, short-term effects on individuals. The specified activities are 
not expected to affect the reproduction or survival of any individual 
marine mammals and, therefore, will not result in impacts on rates of 
recruitment or survival for any species or stock.
    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 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 fewer 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.
    Table 7 demonstrates the number of animals that could be exposed to 
received noise levels that could cause Level A and Level B harassment 
for the work in Auke Bay. Our analysis shows that less than 28.5 
percent of each affected stock could be taken by harassment. The 
numbers of animals to be taken for these stocks will be considered 
small relative to the relevant stock's abundances, even if each 
estimated taking occurred to a new individual--an extremely unlikely 
scenario.
    Based on the analysis contained herein of the activity (including 
the mitigation and monitoring measures) and the anticipated take of 
marine mammals, NMFS finds that small numbers of marine mammals will be 
taken relative to the population size of the affected species or 
stocks.

Unmitigable Adverse Impact Analysis and Determination

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity: (1) 
That is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet

[[Page 2598]]

subsistence needs by: (i) Causing the marine mammals to abandon or 
avoid hunting areas; (ii) Directly displacing subsistence users; or 
(iii) Placing physical barriers between the marine mammals and the 
subsistence hunters; and (2) That cannot be sufficiently mitigated by 
other measures to increase the availability of marine mammals to allow 
subsistence needs to be met.
    The project is not known to occur in an area important for 
subsistence hunting. It is a developed area with regular marine vessel 
traffic. However, ADOT&PF plans to provide advanced public notice of 
construction activities to reduce construction impacts on local 
residents, ferry travelers, adjacent businesses, and other users of the 
Auke Bay ferry terminal and nearby areas. This will include 
notification to local Alaska Native tribes that may have members who 
hunt marine mammals for subsistence. Of the marine mammals considered 
in this IHA application, only harbor seals are known to be used for 
subsistence in the project area. If any tribes express concerns 
regarding project impacts to subsistence hunting of marine mammals, 
further communication between will take place, including provision of 
any project information, and clarification of any mitigation and 
minimization measures that may reduce potential impacts to marine 
mammals.
    Based on the description of the specified activity, the measures 
described to minimize adverse effects on the availability of marine 
mammals for subsistence purposes, and the mitigation and monitoring 
measures, NMFS has determined that there will not be an unmitigable 
adverse impact on subsistence uses from ADOT&PF's activities.

Endangered Species Act

    There are two marine mammal species (western DPS Steller sea lion 
and Mexico DPS humpback whale) with confirmed occurrence in the project 
area that is listed as endangered and threatened respectively under the 
ESA. The NMFS Alaska Regional Office Protected Resources Division 
issued a Biological Opinion on December 22, 2023 under section 7 of the 
ESA, on the issuance of an IHA to ADOT&PF under section 101(a)(5)(D) of 
the MMPA by the NMFS Permits and Conservation Division. The Biological 
Opinion concluded that this action is not likely to jeopardize the 
continued existence of western DPS Steller sea lions or Mexico DPS 
humpback whale, and is not likely to destroy or adversely modify 
western DPS Steller sea lion or Mexico DPS humpback whale critical 
habitats.

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 an IHA) and 
alternatives 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 will preclude this 
categorical exclusion. Accordingly, NMFS has determined that the 
issuance of this IHA qualifies to be categorically excluded from 
further NEPA review.

Authorization

    NMFS has issued an IHA to ADOT&PF for the potential harassment of 
small numbers of 11 marine mammal species incidental to the 
construction project in Auke Bay, Alaska, that includes the previously 
explained mitigation, monitoring and reporting requirements. The issued 
IHA can be found at: https://www.fisheries.noaa.gov/action/incidental-take-authorization-alaska-department-transportation-pile-driving-and-removal.

    Dated: January 9, 2024.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2024-00622 Filed 1-12-24; 8:45 am]
BILLING CODE 3510-22-P