Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Sitka Seaplane Base Construction, 39591-39604 [2024-10145]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 89, Number 91 (Thursday, May 9, 2024)]
[Notices]
[Pages 39591-39604]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-10145]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XD743]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Sitka Seaplane Base Construction

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

ACTION: Notice; issuance of two incidental harassment authorizations.

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SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA) as amended, notification is hereby given 
that NMFS has issued two consecutive incidental harassment 
authorizations (IHAs) to City and Borough of Sitka (CBS) to 
incidentally harass marine mammals during construction activities 
associated with the CBS' Sitka Seaplane Base project, in Sitka, Alaska.

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

ADDRESSES: Electronic copies of the application and supporting 
documents, as well as a list of the references cited in this document, 
may be obtained online at: https://www.fisheries.noaa.gov/action/incidental-take-authorization-city-and-borough-sitkas-seaplane-base-construction-activities. In case of problems accessing these documents, 
please call the contact listed below.

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

SUPPLEMENTARY INFORMATION: 

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are proposed or, if the taking is limited to harassment, a notice of a 
proposed IHA is provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the 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 1, 2023, NMFS received a request from CBS for two IHAs 
to take marine mammals incidental to the Sitka seaplane base 
construction project in Sitka, Alaska, over the course of 2 years. 
Following NMFS' review of the application and a revised version, CBS 
submitted a final version on November 15, 2023. The application was 
deemed adequate and complete on December 1, 2023. The notice of 
proposed IHAs published for public comment on January 11, 2024 (89 FR 
1884). For both IHAs, CBS's request is for take of seven species of 
marine mammals by Level B harassment and, for a subset of three of 
these species, Level A harassment. Neither CBS nor

[[Page 39592]]

NMFS expect serious injury or mortality to result from this activity 
and, therefore, IHAs are appropriate.

Description of Activity

    CBS plans to replace the existing seaplane base in the Sitka 
Channel in Sitka, Alaska. The purpose of this project is to construct a 
new seaplane base, which would address existing capacity, safety, and 
condition deficiencies for critical seaplane operations, and for all 
seaplanes to transit the Sitka Chanel more safely. The planned location 
of the new seaplane base in the Sitka Channel is located on the 
northern shore of Japonski Island in the Sitka Sound. Over the course 
of 2 years spanning July 2024-June 2025 and July 2025-June 2026, CBS 
would use a variety of methods, including vibratory and impact pile 
driving, and down-the-hole (DTH) drilling to install and remove piles.
    Phase I would involve the installation and removal of temporary 
piles, and the installation of permanent piles. During Phase I, 10 16-
inch (in, 0.4 meter (m)) and 16 24-in (0.6 m) permanent steel piles 
would be installed. The installation and removal of 12 temporary 16-in 
(0.4 m) steel pipe piles would be completed to support permanent pile 
installation. Vibratory hammers, impact hammers, and DTH drilling would 
be used for the installation and removal of the piles (table 1). The 
installation and removal of temporary piles would be conducted using 
impact and vibratory hammers. All permanent piles would be initially 
installed with a vibratory hammer. After vibratory driving, piles would 
be socketed into the bedrock with DTH drilling equipment. Finally, 
piles would be driven the final few inches of embedment with an impact 
hammer.
    Phase II similarly would involve the installation and removal of 
temporary piles, and the installation of permanent piles. During Phase 
II six 24-in (0.6 m) steel piles would be installed. The installation 
and removal of six temporary 16-in (0.4 m) steel pipe piles would be 
completed to support the permanent pile installation. As in Phase I, 
vibratory hammers, impact hammers, and DTH drilling would be used for 
the installation and removal of the piles (table 2). The installation 
and removal of temporary piles would be conducted using impact and 
vibratory hammers. All permanent piles would be initially installed 
with a vibratory hammer. After vibratory driving, piles would be 
socketed into the bedrock with DTH drilling equipment. Finally, piles 
would be driven the final few inches of embedment with an impact 
hammer.
    A further detailed description of the planned construction project 
is provided in the Federal Register notice for the proposed IHAs (89 FR 
1884, January 11, 2024). Since that time, no changes have been made to 
the planned activities. Therefore, a detailed description is not 
provided here. Please refer to that Federal Register notice for the 
description of the specified activity. Mitigation, monitoring, and 
reporting measures are described in detail later in this document 
(please see Mitigation and Monitoring and Reporting).

Comments and Responses

    A notice of NMFS' proposal to issue two consecutive IHAs to CBS was 
published in the Federal Register on January 11, 2024 (89 FR 1884). 
That notice described, in detail, CBS' activity, the marine mammal 
species that may be affected by the activity, and the anticipated 
effects on marine mammals. During that 30-day public comment period, no 
comments were received.

Changes From the Proposed IHAs for Final IHAs

    Changes were made between publication of the notice of proposed 
IHAs and this notice of final IHAs. Changes have been made to correct 
typographical errors and inconsistences in the high frequency shutdown 
zones in both the Phase I and Phase II IHAs to reflect the correct 
shutdown zones included in the proposed Federal Register notice.

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, instead of reprinting the information. Additional 
information regarding population trends and threats may be found in 
NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and 
more general information about these species (e.g., physical and 
behavioral descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
    Table 1 lists all species or stocks for which take is expected and 
authorized for this activity and summarizes information related to the 
population or stock, including regulatory status under the MMPA and 
Endangered Species Act (ESA) and potential biological removal (PBR), 
where known. PBR is defined by the MMPA as the maximum number of 
animals, not including natural mortalities, that may be removed from a 
marine mammal stock while allowing that stock to reach or maintain its 
optimum sustainable population (as described in NMFS' SARs). While no 
serious injury or mortality is anticipated or authorized here, PBR and 
annual serious injury and mortality from anthropogenic sources are 
included here as gross indicators of the status of the species or 
stocks and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Alaska Marine Mammal SARs. All values presented in table 1 
are the most recent available final SAR at the time of publication of 
NMFS' proposed IHAs and are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

[[Page 39593]]



                                              Table 1--Species Likely Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         ESA/ MMPA status;   Stock abundance (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae (rorquals):
    Humpback Whale..................  Megaptera novaeangliae.  Hawai[revaps]i.........  -,-,N               11,278 (0.56, 7,265,          127         27
                                                                                                             2020).
                                                               Mexico-North Pacific...  T,D,Y               N/A (N/A, N/A, 2006)..        UND        0.6
    Minke Whale.....................  Balaenoptera             Alaska.................  -,-,N               N/A (N/A, N/A, 2018)..  .........          0
                                       acutorostrata.
Family Eschrichtiidae:
    Gray Whale......................  Eschrichtius robustus..  Eastern North Pacific..  -,-,N               26,960 (0.05, 25,849,         801        131
                                                                                                             2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Killer whale....................  Orca orcinus...........  Northern Resident......  -,-,N               302 (N/A, 302, 2018)..        2.2        0.2
                                                               Alaska Resident........  -,-,N               1,920 (N/A, 1,920,             19        1.3
                                                                                                             2019).
                                                               Gulf of Alaska/Aleutian  -,-,N               587 (N/A, 587, 2012)..        5.9        0.8
                                                                Islands/Bering Sea
                                                                Transient.
                                                               West Coast Transient...  -,-,N               349 (N/A, 349, 2018)..        3.5        0.4
Family Phocoenidae (porpoises):
    Harbor porpoise.................  Phocoena phocoena......  Northern Southeast       -,-,N               1,619 (0.26, 1,250,            13        5.6
                                                                Alaska.                                      2019).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    Steller sea lion................  Eumetopias jubatus.....  Western Stock..........  E,D,Y               52,932 (N/A, 52,932,          318        254
                                                                                                             2019).
                                                               Eastern Stock..........  -,-,N               43,201 (N/A, 43,201,        2,592        112
                                                                                                             2017).
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vituline           Sitka/Chatham..........  -,-,N               13,289 (N/A, 11,883,          356         77
                                       richardii.                                                            2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
  designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or
  which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is
  automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal SARs online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports CV is
  coefficient of variation; Nmin is the minimum estimate of stock abundance.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.

    As indicated above, all 7 species (with 12 managed stocks) in table 
1 temporally and spatially co-occur with the activity to the degree 
that take is reasonably likely to occur. All species that could 
potentially occur in the action area are included in table 8 of the IHA 
application. While northern fur seal, Pacific white-sided dolphin, 
Dall's porpoise, North Pacific right whale, sperm whale, fin whale, and 
Cuvier's beaked whale have been documented in or near Sitka Sound and 
Sitka Channel, the temporal and/or spatial occurrence of these species 
is such that take is not expected to occur, and they are not discussed 
further beyond the explanation provided here. These species are all 
considered to be rare (no sightings in recent years) or very rare (no 
local knowledge of sightings within the project vicinity) within Sitka 
Sound or near the action area. The take of these species has not been 
requested nor is authorized and these species are not considered 
further in this document. Additionally, the Northern Sea Otter may be 
found in Sitka Sound. However, the Northern Sea Otter are managed by 
the U.S. Fish and Wildlife Service and are not considered further in 
this document.
    A detailed description of the species likely to be affected by CBS' 
construction project, were provided in the Federal Register notice for 
the proposed IHAs (89 FR 1884, January 11, 2024). Since that time, we 
are not aware of any changes in the status of these species and stocks; 
therefore, detailed descriptions are not provided here. Please refer to 
the Federal Register notice for these descriptions. Please also refer 
to the NMFS website (https://www.fisheries.noaa.gov/find-species) for 
generalized species descriptions.

Marine Mammal Hearing

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

[[Page 39594]]

exception for lower limits for low-frequency cetaceans where the lower 
bound was deemed to be biologically implausible and the lower bound 
from Southall et al. (2007) retained. Marine mammal hearing groups and 
their associated hearing ranges are provided in table 2.

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

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al., 
2013).
    For more detail concerning these groups and associated frequency 
ranges, 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 CBS' pile driving activities 
have the potential to result in behavioral harassment of marine mammals 
in the vicinity of the project area. The notice of the proposed IHAs 
(89 FR 1884, January 11, 2024) included a discussion of the effects of 
anthropogenic noise on marine mammals and the potential effects of 
under noise from CBS' pile driving activities on marine mammals and 
their habitat. Please refer to the notice of the proposed IHAs (89 FR 
1884, January 11, 2024) for that information and analysis, which is not 
repeated here.

Estimated Take of Marine Mammals

    This section provides an estimate of the number of incidental takes 
authorized through the IHAs, which will inform NMFS' consideration of 
``small numbers,'' and the negligible impact determinations.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as 
vibratory or impact pile driving and DTH drilling has the potential to 
result in disruption of behavioral patterns for individual marine 
mammals. There is also some potential for auditory injury (Level A 
harassment) to result, primarily for harbor porpoise, harbor seals and 
Steller sea lions. Harbor porpoise have larger predicted auditory 
injury zones and due to their small size, they could enter the Level A 
harassment zone and remain undetected for sufficient duration to incur 
auditory injury. While Steller sea lion do not have large Level A 
harassment zones, they are frequently sighted in the project area and 
therefor have some potential for auditory injury. Additionally harbor 
seals have larger Level A harassment zones and are common in the action 
area, and therefore have potential for auditory injury. Auditory injury 
is unlikely to occur for all other species, based on the unlikelihood 
of the species in the action area and the smaller Level A harassment 
zones. The mitigation and monitoring measures are expected to minimize 
the severity of the taking to the extent practicable.
    As described previously, no serious injury or mortality is 
anticipated or authorized for this activity. Below we describe how the 
take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) acoustic thresholds above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed or incur some degree of permanent hearing impairment; (2) the 
area or volume of water that will be ensonified above these levels in a 
day; (3) the density or occurrence of marine mammals within these 
ensonified areas; and (4) the number of days of activities. We note 
that while these factors can contribute to a basic calculation to 
provide an initial prediction of potential takes, additional 
information that can qualitatively inform take estimates is also 
sometimes available (e.g., previous monitoring results or average group 
size). Below, we describe the factors considered here in more detail 
and present the take estimates.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur permanent threshold shift (PTS) of some 
degree (equated to Level A harassment).
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007, 2021; Ellison et al., 2012). 
Based on what the available science indicates and the practical need to 
use a threshold based on a metric that is both predictable and 
measurable for most activities, NMFS typically uses a generalized 
acoustic

[[Page 39595]]

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 (RMS SPL) of 120 dB (referenced 
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile 
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g., 
scientific sonar) sources. Generally speaking, Level B harassment take 
estimates based on these behavioral harassment thresholds are expected 
to include any likely takes by temporary threshold shift (TTS) as, in 
most cases, the likelihood of TTS occurs at distances from the source 
less than those at which behavioral harassment is likely. TTS of a 
sufficient degree can manifest as behavioral harassment, as reduced 
hearing sensitivity and the potential reduced opportunities to detect 
important signals (conspecific communication, predators, prey) may 
result in changes in behavior patterns that would not otherwise occur.
    CBS's planned activity includes the use of continuous (vibratory 
hammer and DTH drilling) and impulsive (DTH drilling and 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). CBS's 
planned activity includes the use of impulsive (impact pile driving and 
DTH drilling) and non-impulsive (vibratory hammer and DTH drilling) 
sources.
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

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

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that are used in estimating the area ensonified above the 
acoustic thresholds, including source levels and transmission loss 
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, and DTH).
    In order to calculate distances to the Level A harassment and Level 
B harassment thresholds for the methods and piles being used in this 
project, NMFS used acoustic monitoring data from other locations to 
develop source levels for the various pile types, sizes and methods 
(table 4). This analysis uses practical spreading loss, a standard 
assumption regarding sound propagation for similar environments, to 
estimate transmission of sound through water. For this analysis, the 
transmission loss factor of 15 (4.5 dB per doubling of distance) is 
used. A weighting adjustment factor of 2.5 or 2, a standard default 
value for vibratory pile driving and removal or impact driving and DTH 
respectively, were used to calculate Level A harassment areas.
    NMFS recommends treating DTH systems as both impulsive and 
continuous, non-impulsive sound source types simultaneously. Thus, 
impulsive thresholds are used to evaluate Level A harassment, and 
continuous thresholds are used to evaluate Level B harassment. With 
regards to DTH mono-hammers, NMFS recommends proxy levels for Level A 
harassment based on available data regarding DTH systems of similar 
sized piles and holes (Denes et al., 2019; Guan and Miner, 2020; Reyff 
and Heyvaert, 2019; Reyff, 2020; Heyvaert and Reyff, 2021).

[[Page 39596]]



               Table 4--Estimates Underwater Proxy Source Level for Pile Installation and Removal
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
Method and pile type                            Sound source at 10 meters            Source
----------------------------------------------------------------------------------------------------------------
Vibratory Hammer                                         dB rms
----------------------------------------------------------------------------------------------------------------
16 in..............................                        161                       NAVFAC 2015.
24 in..............................                        161                       NAVFAC 2015.
----------------------------------------------------------------------------------------------------------------
DTH Drill                                    dB rms          dB SEL         dB peak
----------------------------------------------------------------------------------------------------------------
16 in..............................             167             146             172  Heyvaert and Reyff 2021,
                                                                                      Guan and Miner 2020.
24 in..............................             167             159             184  Heyvaert and Reyff 2021.
----------------------------------------------------------------------------------------------------------------
Impact Hammer                                dB rms          dB SEL         dB peak
----------------------------------------------------------------------------------------------------------------
16 in..............................             185             175             200  Caltrans 2020.
24 in..............................             190             177             203  Caltrans 2015.
----------------------------------------------------------------------------------------------------------------

Level B Harassment Zones

    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 * log10 (R1/R2),

Where:

TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R1 = the distance of the modeled SPL from the driven 
pile, and
R2 = the distance from the driven pile of the initial 
measurement.

    The recommended TL coefficient for most nearshore environments is 
the practical spreading value of 15. This value results in an expected 
propagation environment that would lie between spherical and 
cylindrical spreading loss conditions, which is the most appropriate 
assumption for CBS's planned underwater activities. The Level B 
harassment zones and approximate amount of area ensonified for the 
underwater activities are shown in table 5.

Level A Harassment Zones

    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 pile installation or 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 
would be expected to incur PTS. The isopleths generated by the User 
Spreadsheet used the same TL coefficient as the Level B harassment zone 
calculations (i.e., the practical spreading value of 15). Inputs used 
in the User Spreadsheet (e.g., number of piles per day, duration and/or 
strikes per pile) are presented in tables 1 and 2. The maximum RMS SPL, 
sound exposure level (SEL), and resulting isopleths are reported in 
tables 4 and 5.

                  Table 5--Level A and Level B Harassment Isopleths for Pile Driving Activities
----------------------------------------------------------------------------------------------------------------
                                                       Level A isopleth (m)
            Activity            -----------------------------------------------------------------     Level B
                                      LF           MF           HF        Phocids      Otariids    isopleth (m)
----------------------------------------------------------------------------------------------------------------
                                       Vibratory Pile Removal/Installation
----------------------------------------------------------------------------------------------------------------
Phase I:
    16- in temp install........          6.8          0.6         10.1          4.2          0.3         5,411.7
    16-in temp removal.........          6.8          0.6         10.1          4.2          0.3         5,411.7
    16-in perm install.........          6.8          0.6         10.1          4.2          0.3         5,411.7
    24-in perm install.........          6.8          0.6         10.1          4.2          0.3         5,411.7
Phase II:
    16- in temp install........          6.8          0.6         10.1          4.2          0.3         5,411.7
    16-in temp removal.........          6.8          0.6         10.1          4.2          0.3         5,411.7
    24-in perm install.........          6.8          0.6         10.1          4.2          0.3         5,411.7
----------------------------------------------------------------------------------------------------------------
                                              DTH Pile Installation
----------------------------------------------------------------------------------------------------------------
Phase I:
    16-in perm install.........           59          2.1         70.3         31.6          2.3       \1\ 8,500
    24-in perm install.........        568.9         20.2        677.6        304.4         22.2       \1\ 8,500
Phase II:
    24-in perm install.........        568.9         20.2        677.6        304.4         22.2       \1\ 8,500
----------------------------------------------------------------------------------------------------------------

[[Page 39597]]

 
                                            Impact Pile Installation
----------------------------------------------------------------------------------------------------------------
Phase I:
    16-in temp install.........          231          8.2          275          123            9           464.2
    16-in perm install.........          231          8.2          275          123            9           464.2
    24-in perm install.........          313         11.1          373          168         12.2           1,000
Phase II:
    16-in temp install.........          231          8.2          275          123            9           464.2
    24-in perm install.........          313         11.1          373          168         12.2           1,000
----------------------------------------------------------------------------------------------------------------
\1\ The calculated Level B harassment zone is 13,594 m. However, the farthest distance that sound will transmit
  from the source is 8,500 m before transmission is stopped by landmasses.

Marine Mammal Occurrence

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information which 
will inform the take calculations.
    Daily occurrence probability of each marine mammal species in the 
action area is based on consultation with previous monitoring reports, 
local researchers and marine professionals. Occurrence probability 
estimates are based on conservative density approximations for each 
species and factor in historic data of occurrence, seasonality, and 
group size in Sitka Sound and Sitka Channel. A summary of species 
occurrence is shown in table 6. To accurately describe species 
occurrence near the action area, marine mammals were described as 
either common (species sighted consistently during all monitoring 
efforts in the project vicinity, assume one to two groups per day), 
frequent (species sighted with some consistency during most monitoring 
efforts in the project vicinity, assume one group per week), or 
infrequent (species sighted occasionally during a few monitoring 
efforts in the project vicinity, assume one group per 2 weeks).

                    Table 6--Estimated Occurrence of Group Sightings of Marine Mammal Species
----------------------------------------------------------------------------------------------------------------
                                                                Average group
               Species                       Frequency              size              Expected occurrence
----------------------------------------------------------------------------------------------------------------
Humpback whale......................  Frequent...............             3.4  1 group/week.
Minke whale \1\.....................  Infrequent.............             3.5  1 group/2 weeks.
Gray whale..........................  Infrequent.............             3.5  1 group/2 weeks.
Killer whale........................  Frequent...............             6.6  1 group/week.
Harbor porpoise.....................  Infrequent.............             5.0  1 group/2 weeks.
Harbor seal \2\.....................  Common.................             2.1  1-2 groups/day.
Steller sea lion \2\................  Common.................             2.0  1-2 groups/day.
----------------------------------------------------------------------------------------------------------------
\1\ Minke whale considered rare in Sitka Channel, but to be conservative they are treated as infrequent for take
  estimation as there is a small likelihood they could be in the area during the activity.
\2\ Likelihood of one group/day in the Level A harassment zone and likelihood of two groups/day in the level B
  harassment zone.

Take Estimation

    Here we describe how the information provided above is synthesized 
to produce a quantitative estimate of the take that is reasonably 
likely to occur and authorized.
    For the total underwater take estimate, the daily occurrence 
probability for a species was multiplied by the estimated group size 
and by the number of days of each type of pile driving activity. Group 
size is based on the best available published research for these 
species and their presence in the action area.

Estimated take = Group size x Groups per day x Days of pile driving 
activity

    Take by Level A harassment is anticipated for Steller sea lions and 
harbor seals. Although Steller sea lion Level A harassment zones are 
small, as previously discussed they are known to spend extended periods 
of time within the breakwaters in Sitka sound and in the project area. 
Harbor seals are also common in the project area and although their 
Level A harassment zones are farther from the project area, CBS has 
requested a maximum shutdown zone of 125 m for harbor seals and 
therefor there is likelihood for take by Level A harassment of harbor 
seals. Take by Level A harassment is also requested for harbor 
porpoise. We require a maximum shutdown zone for high frequency species 
of 300 m in this case and therefor there is likelihood for some take by 
Level A harassment. Even though they are not as common within the 
breakwaters, their Level A harassment zone extends beyond the 
breakwaters and they are elusive in nature. The take by Level A 
harassment for both pinniped species are based on a lower daily 
occurrence rate based on the frequency of sightings within the smaller 
Level A harassment zone of the breakwaters (table 6).
    Additionally, for species that are large and/or infrequent (gray 
whale, minke whale, humpback whale, and harbor porpoise) in Sitka Sound 
and are unlikely to be within the breakwaters where the action will 
take place, take by Level B harassment is only anticipated to occur 
incidental to vibratory and DTH methods, given the larger Level B 
harassment zones which will extend beyond the breakwaters. Anticipated 
take by Level A harassment for harbor seal and harbor porpoise would 
likely occur only incidental to impact pile driving and DTH drilling, 
and anticipated take of Steller sea lion by Level A harassment would 
likely occur only incidental to DTH drilling, due to

[[Page 39598]]

the larger Level A harassment zones for these activities. See table 5.

                           Table 7--Take of Marine Mammals by Level A and Level B Harassment and Percent of Stock To Be Taken
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                           Phase 1                                Phase 2
                                                                           -----------------------------------------------------------------------------
                  Species                                Stock                                         Percent of                             Percent of
                                                                              Level A      Level B       stock       Level A      Level B       stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale \1\.........................  Hawai[revaps]i...............            0           11          0.1            0          4 *            0
                                             Mexico-North Pacific \2\.....            0            0            0            0            0            0
Gray Whale.................................  Eastern North Pacific........            0            6            0            0          * 4            0
Minke Whale................................  Alaska.......................            0            6           NA            0          * 4           NA
Killer whale...............................  West Coast Transients........            0            3          0.9            0            1          0.3
                                             Gulf, Aleutian, Bering                   0            6          0.9            0            2          0.3
                                              Transient.
                                             Northern Resident............            0            3          0.9            0            1          0.3
                                             Alaska Resident..............            0           18          0.9            0            6          0.3
Harbor porpoise............................  Northern Southeast Alaska....          * 5            8          0.9          * 5          * 5          0.7
Harbor seal................................  Sitka/Chatham Alaska.........           48          130          1.3           13           38          0.4
Steller sea lion...........................  Eastern US...................           16          121          0.3            6           35          0.1
                                             Western US...................            0            3            0            0          * 2            0
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Take estimates are weighted based on calculated percentages of population for each distinct stock, assuming animals present would follow same
  probability of presence in project area. Humpback whale probability by stock based on Southeast Alaska estimates from NMFS 2021 (98 percent Hawaii
  distinct population segment (DPS); 2 percent Mexico DPS).
\2\ ESA listed Mexico humpback whales take calculation resulted in less than 0.5 takes, therefore no takes are anticipated or authorized.
* Where calculated take was less than the average group size, the take was rounded up to a group size as that is likely what would be encountered.

Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses. 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, as 
well as subsistence uses. This considers the nature of the potential 
adverse impact being mitigated (likelihood, scope, range). It further 
considers the likelihood that the measure will be effective if 
implemented (probability of accomplishing the mitigating result if 
implemented as planned), the likelihood of effective implementation 
(probability implemented as planned); and
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, and impact on 
operations.

Mitigation Measures

    For each IHA, CBS must follow mitigation measures as specified 
below:
     Ensure that construction supervisors and crews, the 
monitoring team, and relevant CBS staff are trained prior to the start 
of all pile driving and DTH drilling activity, so that 
responsibilities, communication procedures, monitoring protocols, and 
operational procedures are clearly understood. New personnel joining 
during the project must be trained prior to commencing work;
     Employ Protected Species Observers (PSOs) and establish 
monitoring locations as described in the application and the IHA. The 
Holder must monitor the project area to the maximum extent possible 
based on the required number of PSOs, required monitoring locations, 
and environmental conditions. For all pile driving and removal at least 
one PSO must be used. The PSO will be stationed as close to the 
activity as possible;
     The placement of the PSOs during all pile driving and 
removal and DTH drilling activities will ensure that the entire 
shutdown zone is visible during pile installation;
     Monitoring must take place from 30 minutes prior to 
initiation of pile driving or DTH drilling activity (i.e., pre-
clearance monitoring) through 30 minutes post-completion of pile 
driving or DTH drilling activity;
     Pre-start clearance monitoring must be conducted during 
periods of visibility sufficient for the lead PSO to determine that the 
shutdown zones indicated in table 10 are clear of marine mammals. Pile 
driving and DTH drilling may commence following 30 minutes of 
observation when the determination is made that the shutdown zones are 
clear of marine mammals;
     CBS must use soft start techniques when impact pile 
driving. Soft start requires contractors to provide an initial set of 
three strikes at reduced energy, followed by a 30-second waiting 
period, then two subsequent reduced-energy strike sets. A soft start 
must 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; and
     If a marine mammal is observed entering or within the 
shutdown zones indicated in table 10, pile driving and DTH drilling 
must be delayed or halted. If pile driving is delayed or halted due to 
the presence of a marine mammal, the activity may not commence or 
resume until either the animal has voluntarily exited and been visually 
confirmed beyond the shutdown zone (table 11) or 15 minutes have passed 
without re-detection of the animal.
    As planned by the applicant, in water activities will take place 
only between civil dawn and civil dusk when PSOs can effectively 
monitor for the presence of marine mammals; during conditions with a 
Beaufort sea state of four or less. Pile driving and DTH drilling may 
continue for up to 30 minutes after sunset during evening civil 
twilight, as necessary to secure a pile for safety prior to 
demobilization during this time.

[[Page 39599]]

The length of the post-activity monitoring period may be reduced if 
darkness precludes visibility of the shutdown and monitoring zones.

Shutdown Zones

    CBS will establish shutdown zones for all pile driving and DTH 
drilling activities. The purpose of a shutdown zone is generally to 
define an area within which shutdown of the activity would occur upon 
sighting of a marine mammal (or in anticipation of an animal entering 
the defined area). Shutdown zones would be based upon the Level A 
harassment isopleth for each pile size/type and driving method where 
applicable, as shown in table 10.
    For in-water heavy machinery activities other than pile driving, if 
a marine mammal comes within 10 m, work will stop and vessels will 
reduce speed to the minimum level required to maintain steerage and 
safe working conditions. A 10 m shutdown zone serves to protect marine 
mammals from physical interactions with project vessels during pile 
driving and other construction activities, such as barge positioning or 
drilling. If an activity is delayed or halted due to the presence of a 
marine mammal, the activity may not commence or resume until either the 
animal has voluntarily exited and been visually confirmed beyond the 
shutdown zone indicated in table 10 or 15 minutes have passed without 
re-detection of the animal. Construction activities must be halted upon 
observation of a species for which incidental take is not authorized or 
a species for which incidental take has been authorized but the 
authorized number of takes has been met entering or within the 
harassment zone.
    All marine mammals will be monitored in the Level B harassment 
zones and throughout the area as far as visual monitoring can take 
place. If a marine mammal enters the Level B harassment zone, 
construction activities including in-water work will continue and the 
animal's presence within the estimated harassment zone will be 
documented.
    CBS would also establish shutdown zones for all marine mammals for 
which take has not been authorized or for which incidental take has 
been authorized but the authorized number of takes has been met. These 
zones are equivalent to the Level B harassment zones for each activity. 
If a marine mammal species not covered under this IHA enters the 
shutdown zone, all in-water activities will cease until the animal 
leaves the zone or has not been observed for at least 15 minutes, and 
NMFS will be notified about species and precautions taken. Pile driving 
will proceed if the non-IHA species is observed to leave the Level B 
harassment zone or if 15 minutes have passed since the last 
observation.
    If shutdown and/or clearance procedures would result in an imminent 
safety concern, as determined by CBS or its designated officials, the 
in-water activity will be allowed to continue until the safety concern 
has been addressed, and the animal will be continuously monitored.

                                     Table 8--Shutdown and Monitoring Zones
----------------------------------------------------------------------------------------------------------------
                                                       Level A isopleth (m)
            Activity            -----------------------------------------------------------------     Level B
                                      LF           MF         HF \2\    Phocids \1\    Otariids    isopleth  (m)
----------------------------------------------------------------------------------------------------------------
                                       Vibratory Pile Removal/Installation
----------------------------------------------------------------------------------------------------------------
Phase I:
    16- in temp install........           10           10           20           10           10           5,415
    16-in temp removal.........           10           10           20           10           10           5,415
    16-in perm install.........           10           10           20           10           10           5,415
    24-in perm install.........           10           10           20           10           10           5,415
Phase II:
    16- in temp install........           10           10           20           10           10           5,415
    16-in temp removal.........           10           10           20           10           10           5,415
    24-in perm install.........           10           10           20           10           10           5,415
----------------------------------------------------------------------------------------------------------------
                                              DTH Pile Installation
----------------------------------------------------------------------------------------------------------------
Phase I:
    16-in perm install.........           60           10           75           35           10           8,500
    24-in perm install.........          570           30          300          125           30           8,500
Phase II:
    24-in perm install.........          570           30          300          125           30           8,500
----------------------------------------------------------------------------------------------------------------
                                            Impact Pile Installation
----------------------------------------------------------------------------------------------------------------
Phase I:
    16-in temp install.........          235           10          275          125           10             465
    16-in perm install.........          235           10          275          125           10             465
    24-in perm install.........          315           20          300          125           20           1,000
Phase II:
    16-in temp install.........          235           10          275          125           10             465
    24-in perm install.........          315           20          300          125           20           1,000
----------------------------------------------------------------------------------------------------------------
\1\ Maximum shutdown for phocids is reduced to 125 m as they are a common species within the breakwaters of
  Sitka Sound.
\2\ Maximum shutdown for high frequency species is reduced to 300 m, given the difficulty observing harbor
  porpoise at greater distances.

Protected Species Observers

    The placement of PSOs during all construction activities (described 
in the Monitoring and Reporting section) would ensure that the entire 
shutdown zone is visible. Should environmental conditions deteriorate 
such that the entire shutdown zone would not be visible (e.g., fog, 
heavy rain), pile driving would be delayed until the PSO is confident 
marine mammals within the shutdown zone could be detected.

[[Page 39600]]

    PSOs would monitor the full shutdown zones and the remaining Level 
A harassment and the Level B harassment zones to the extent 
practicable. 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 areas outside the 
shutdown zones and thus prepare for a potential cessation of activity 
should the animal enter the shutdown zone.

Pre-Activity Monitoring

    Prior to the start of daily in-water construction activity, or 
whenever a break in pile driving or DTH drilling of 30 minutes or 
longer occurs, PSOs would observe the shutdown and monitoring zones for 
a period of 30 minutes. The shutdown zone would 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 zones 
listed in table 10, pile driving activity would be delayed or halted. 
If work ceases for more than 30 minutes, the pre-activity monitoring of 
the shutdown zones would commence. A determination that the shutdown 
zone is clear must be made during a period of good visibility (i.e., 
the entire shutdown zone and surrounding waters must be visible to the 
naked eye).

Soft-Start Procedures

    Soft-start procedures 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 would be required to provide an 
initial set of three strikes from the hammer at reduced energy, 
followed by a 30-second waiting period, then two subsequent reduced-
energy strike sets. Soft-start would 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.
    Based on our evaluation of the applicant's measures NMFS has 
determined that the mitigation measures provide the means of effecting 
the least practicable impact on the affected species or stocks and 
their habitat, paying particular attention to rookeries, mating 
grounds, and areas of similar significance.

Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present while 
conducting the activities. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
     Mitigation and monitoring effectiveness.

Visual Monitoring

    Marine mammal monitoring must be conducted in accordance with the 
conditions in this section and the IHA. Marine mammal monitoring during 
pile driving activities would be conducted by PSOs meeting NMFS' 
following requirements:
     PSOs must be independent of the activity contractor (for 
example, employed by a subcontractor) and have no other assigned tasks 
during monitoring periods;
     At least one PSO would have prior experience performing 
the duties of a PSO during construction activity pursuant to a NMFS-
issued incidental take authorization;
     Other PSOs may substitute education (degree in biological 
science or related field) or training for experience; and
     Where a team of three or more PSOs is required, a lead 
observer or monitoring coordinator would be designated. The lead 
observer would be required to have prior experience working as a marine 
mammal observer during construction.
    PSOs should have the following additional qualifications:
    [cir] Ability to conduct field observations and collect data 
according to assigned protocols;
    [cir] Experience or training in the field identification of marine 
mammals, including the identification of behaviors;
    [cir] Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    [cir] Writing skills sufficient to prepare a report of observations 
including but not limited to the number and species of marine mammals 
observed; dates and times when in-water construction activities were 
conducted; dates, times and reason for implementation of mitigation (or 
why mitigation was not implemented when required); and marine mammal 
behavior; and
    [cir] 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.
     CBS must employ up to five PSOs depending on the size of 
the monitoring and shutdown zones. A minimum of two PSOs (including the 
lead PSO) must be assigned to the active pile driving location to 
monitor the shutdown zones and as much of the Level B harassment zones 
as possible.
     CBS must establish monitoring locations with the best 
views of monitoring zones as described in the IHA and Monitoring Plan 
posted on our website.
     Up to four monitors will be used at a time depending on 
the size of the monitoring area. PSOs would be deployed in strategic 
locations around the area of potential effects at all times during in-
water pile driving and removal. PSOs will be positioned at

[[Page 39601]]

locations that provide full views of the monitoring zones and the Level 
A harassment Shutdown Zones. All PSOs would have access to high-quality 
binoculars, range finders to monitor distances, and a compass to record 
bearing to animals as well as radios or cells phones for maintaining 
contact with work crews.
     Up to four PSOs will be stationed at the following 
locations: the project site, Sandy Beach Day use site, O'Connell 
lightering float, and Whale Park.
    Monitoring would be conducted 30 minutes before, during, and 30 
minutes after all in water construction activities. In addition, PSOs 
would record all incidents of marine mammal occurrence, regardless of 
distance from activity, and would document any behavioral reactions in 
concert with distance from piles being driven or removed. Pile driving 
activities include the time to install or remove a single pile or 
series of piles, as long as the time elapsed between uses of the pile 
driving equipment is no more than 30 minutes.
    CBS shall conduct briefings between construction supervisors and 
crews, PSOs, CBS staff prior to the start of all pile driving 
activities and when new personnel join the work. These briefings would 
explain responsibilities, communication procedures, marine mammal 
monitoring protocol, and operational procedures.

Reporting

    A draft marine mammal monitoring report will be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities for each IHA, or 60 days prior to a requested date of 
issuance from any future IHAs for projects at the same location, 
whichever comes first. The report will include an overall description 
of work completed, a narrative regarding marine mammal sightings, and 
associated PSO data sheets. Specifically, the report must include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     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, vibratory, or DTH drilling) 
and the total equipment duration for vibratory removal for each pile or 
total number of strikes for each pile (impact driving);
     PSO locations during marine mammal monitoring;
     Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
     Upon observation of a marine mammal, the following 
information:
     Name of PSO who sighted the animal(s) and PSO location and 
activity at the time of sighting;
     Time of sighting;
     Identification of the animal(s) (e.g., genus/species, 
lowest possible taxonomic level, or unidentifiable), 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 sightings (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, sex class, 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 resulted from the 
activity (e.g., no response or changes in behavioral state such as 
ceasing feeding, changing direction, flushing, or breaching);
     Number of marine mammals detected within the harassment 
zones and shutdown zones; by species; and
     Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensured, and resulting changes in behavior of the 
animal(s), if any.
    If no comments are received from NMFS within 30 days, the draft 
reports will constitute the final reports. 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 event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the IHA-holder must 
immediately cease the specified activities and report the incident to 
the Office of Protected Resources (OPR) 
([email protected]), NMFS and to the Alaska Regional 
Stranding Coordinator as soon as feasible. If the death or injury was 
clearly caused by the specified activity, CBS must immediately cease 
the specified activities until NMFS is able to review the circumstances 
of the incident and determine what, if any, additional measures are 
appropriate to ensure compliance with the terms of the IHA. The IHA-
holder must not resume their activities until notified by NMFS. The 
report must include the following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), as well as 
effects on habitat, and the likely effectiveness of the mitigation. We 
also assess the number, intensity, and context of estimated takes by 
evaluating this information relative to population status. Consistent 
with the 1989 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

[[Page 39602]]

human-caused mortality, or ambient noise levels).
    To avoid repetition, the discussion of our analysis applies to all 
species listed in table 3, given that the anticipated effects of this 
activity on these different marine mammal stocks are expected to be 
similar. There is little information about the nature or severity of 
the impacts, or the size, status, or structure of any of these species 
or stocks that would lead to a different analysis for this activity. In 
addition, because both the number and nature of the estimated takes 
anticipated to occur are identical in Phase I and II, the analysis 
below applies to both of the IHAs.
    Pile driving and DTH drilling 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 B harassment and, for some 
species, Level A harassment from underwater sounds generated by pile 
driving and DTH drilling. Potential takes could occur if individuals 
are present in the ensonified zone when these activities are underway.
    No serious injury or mortality would be expected, even in the 
absence of required mitigation measures, given the nature of the 
activities. Further, no take by Level A harassment is anticipated for 
killer whales, humpback whales, gray whales, or minke whales due to the 
application of planned mitigation measures, such as shutdown zones that 
encompass the Level A harassment zones for the species, the rarity of 
the species near the action area, and the small Level A harassment 
zones (for killer whales only). The potential for harassment would be 
minimized through the construction method and the implementation of the 
planned mitigation measures (see Mitigation section).
    Take by Level A harassment is authorized for three species (harbor 
porpoise, Steller sea lion, and harbor seal) as the Level A harassment 
isopleths exceed the size of the shutdown zones for specific 
construction scenarios, the Level A harassment zones are large, and/or 
the species is frequent near the action area. Therefore, there is the 
possibility that an animal could enter a Level A harassment zone and 
remain within that zone for a duration long enough to incur PTS. Level 
A harassment of these species is therefore authorized. Any take by 
Level A harassment is expected to arise from, at most, a small degree 
of PTS (i.e., minor degradation of hearing capabilities within regions 
of hearing that align most completely with the energy produced by 
impact pile driving such as the low-frequency region below 2 kHz), not 
severe hearing impairment or impairment within the ranges of greatest 
hearing sensitivity. Animals would need to be exposed to higher levels 
and/or longer duration than are expected to occur here in order to 
incur any more than a small degree of PTS.
    Further, the amount of take authorized by Level A harassment is 
very low for the marine mammal stocks and species. If hearing 
impairment occurs, it is most likely that the affected animal would 
lose only a few decibels in its hearing sensitivity. Due to the small 
degree anticipated, any PTS potential incurred would not be expected to 
affect the reproductive success or survival of any individuals, much 
less result in adverse impacts on the species or stock.
    The Level A harassment zones identified in table 7 are based upon 
an animal exposed to pile driving or DTH drilling of several piles per 
day (six piles per day for vibratory removal and installation, four 
piles per day of impact driving, and two piles per day of DTH 
drilling). Given the short duration to impact drive or vibratory 
install or remove, or use DTH drilling, each pile and break between 
pile installations (to reset equipment and move piles into place), an 
animal would have to remain within the area estimated to be ensonified 
above the Level A harassment threshold for multiple hours. This is 
highly unlikely given marine mammal movement patterns in the area. If 
an animal was exposed to accumulated sound energy, the resulting PTS 
would likely be small (e.g., PTS onset) at lower frequencies where pile 
driving energy is concentrated, and unlikely to result in impacts to 
individual fitness, reproduction, or survival.
    Additionally, some subset of the individuals that are behaviorally 
harassed could also simultaneously incur some small degree of TTS for a 
short duration of time. However, since the hearing sensitivity of 
individuals that incur TTS is expected to recover completely within 
minutes to hours, it is unlikely that the brief hearing impairment 
would affect the individual's long-term ability to forage and 
communicate with conspecifics, and would therefore not likely impact 
reproduction or survival of any individual marine mammal, let alone 
adversely affect rates of recruitment or survival of the species or 
stock.
    The nature of the pile driving project precludes the likelihood of 
serious injury or mortality. For all species and stocks, take would 
occur within a limited, confined area (adjacent to the project site) of 
the stock's range. The intensity and duration of take by Level A and 
Level B harassment would be minimized through use of mitigation 
measures described herein. Further, the amount of take authorized is 
extremely small when compared to stock abundance.
    Behavioral responses of marine mammals to pile driving, pile 
removals, and DTH drilling in Sitka Channel and the surrounding Sitka 
Sound are expected to be mild, short term, and temporary. Marine 
mammals within the Level B harassment zones may not show any visual 
cues they are disturbed by activities or they could become alert, avoid 
the area, leave the area, or display other mild responses that are not 
observable such as changes in vocalization patterns. Given that pile 
driving, pile removal, and DTH drilling are temporary activities and 
effects would cease when equipment is not operating, any harassment 
occurring would be temporary. Additionally, many of the species present 
in the region would only be present temporarily based on seasonal 
patterns or during transit between other habitats. These species would 
be exposed to even smaller periods of noise-generating activity, 
further decreasing the impacts.
    Nearly all inland waters of southeast Alaska, including Sitka 
Sound, are included in the southeast Alaska humpback whale feeding 
Biologically Important Area (BIA) (Wild et al., 2023), though humpback 
whale distribution in southeast Alaska varies by season and waterway 
(Dahlheim et al., 2009). Humpback whales could be present within Sitka 
Sound year round, however the action area is within the breakwaters 
where humpback whales are not commonly found and therefore, the BIA is 
not expected to be affected. Therefore, the planned project is not 
expected to have significant adverse effects on the foraging of 
humpback whales.
    Sitka Sound is also within a gray whale migratory corridor BIA 
(Wild et al., 2023). Construction is expected to occur while the BIA is 
active during the southbound migration (November to January) and 
northbound migration (March to May). The Sound is also a Gray whale 
feeding BIA. Construction is expected to overlap with the feeding BIA 
(March to June). However, as noted for humpback whales, project 
activities will only overlap seasonally in the gray whale migratory and 
feeding BIAs, and the overall 2 year project (Phase I and Phase II) is 
expected to occur over just 40 in-water workdays, further reducing the 
temporal overlap with the BIAs.

[[Page 39603]]

Additionally, the area of the feeding BIA in which impacts of the 
planned project may occur is small relative to both the overall area of 
the BIA and the overall area of suitable gray whale habitat outside of 
this BIA. The area of Sitka Sound affected by this project is also 
small relative to the rest of the Sound, such that it allows animals 
within the migratory corridor to still utilize Sitka Sound without 
necessarily being disturbed by the construction. Specifically, all 
Level A harassment isopleths for gray whale are within the breakwaters 
where gray whales are not expected. Therefore, take of gray whales 
using the feeding and migratory BIAs is not expected to impact feeding 
or migratory behavior and, therefore, would not impact reproduction or 
survivorship.
    As noted previously, since January 1, 2019, elevated gray whale 
strandings have occurred along the west coast of North America from 
Mexico through Alaska. The event has been declared an unusual mortality 
event (UME), though a cause has not yet been determined. While six 
takes by Level B harassment in phase I and four takes by Level B 
harassment in phase II of gray whale are authorized for each year this 
is an extremely small portion of the stock (<1 percent), and CBS will 
be required to implement a shutdown zone that includes the entire Level 
A harassment zone for low-frequency cetaceans such as gray whales.
    The same regions are also a part of the Western DPS Steller sea 
lion ESA critical habitat. While Steller sea lions are common in the 
project area, there are no essential physical and biological habitat 
features, such as haulouts or rookeries, within the project area. The 
nearest haulout is approximately 25 kilometers away from the project 
area. Therefore, the project is not expected to have significant 
adverse effects on the critical habitat of Western DPS Steller sea 
lions. 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 addition, it is unlikely that minor noise effects in a small, 
localized area of habitat would have any effect on each stock's ability 
to recover. 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 
would have only minor, short-term effects on individuals. The specified 
activities are not expected to impact rates of recruitment or survival 
and would therefore not result in population-level impacts.
    In summary and as described above, the following factors primarily 
support our determination that the impacts resulting from this activity 
are not expected to adversely affect any of the species or stocks 
through effects on annual rates of recruitment or survival:
     No serious injury or mortality is anticipated or 
authorized;
     Level A harassment would be very small amounts and of low 
degree;
     Level A harassment takes of only harbor porpoise, Steller 
sea lions and harbor seals;
     For all species, the Sitka Sound and channel are a very 
small and peripheral part of their range;
     Anticipated takes by Level B harassment are relatively low 
for all stocks. Level B harassment would be primarily in the form of 
behavioral disturbance, resulting in avoidance of the project areas 
around where impact or vibratory pile driving is occurring, with some 
low-level TTS that may limit the detection of acoustic cues for 
relatively brief amounts of time in relatively confined footprints of 
the activities;
     Effects on species that serve as prey for marine mammals 
from the activities are expected to be short-term and, therefore, any 
associated impacts on marine mammal feeding are not expected to result 
in significant or long-term consequences for individuals, or to accrue 
to adverse impacts on their populations;
     The ensonified areas are very small relative to the 
overall habitat ranges of all species and stocks, and would not 
adversely affect ESA-designated critical habitat for any species or any 
areas of known biological importance;
     The lack of anticipated significant or long-term negative 
effects to marine mammal habitat; and
     CBS would implement mitigation measures including soft-
starts and shutdown zones to minimize the numbers of marine mammals 
exposed to injurious levels of sound, and to ensure that take by Level 
A harassment is, at most, a small degree of PTS.
    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, specific to 
each of the 2 consecutive years of planned activity, would 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.
    The amount of take NMFS authorized, for each of the 2 consecutive 
years of the activity, is below one third of the estimated stock 
abundance for all species (in fact, take of individuals is less than 2 
percent of the abundance of the affected stocks, see table 9). This is 
likely a conservative estimate because we assume all takes are of 
different individual animals, which is likely not the case. Some 
individuals may return multiple times in a day, but PSOs would count 
them as separate takes if they cannot be individually identified.
    There is no current or historical estimate of the Alaska minke 
whale stock, but there are known to be over 1,000 minke whales in the 
Gulf of Alaska (Muto et al., 2018), so the 10 takes by Level B 
harassment over the 2 years of the project duration is small relative 
to estimated survey abundance, even if each take occurred to a new 
individual. Additionally, the range of the Alaska stock of minke whales 
is extensive, stretching from the Canadian Pacific coast to the Chukchi 
Sea, and CBS's project would only impact a small portion of this range.
    Based on the analysis contained herein of the planned activity 
(including the mitigation and monitoring measures) and the anticipated 
take of marine mammals, NMFS finds that, for each of the two IHAs, 
small numbers of marine mammals would be taken relative to the 
population size of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact''

[[Page 39604]]

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 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.
    Sitka Channel and other nearby areas are within the traditional 
territory of the Sheet[revaps]k[aacute] Kgw[aacute]an. Alaska natives 
have traditionally harvested marine mammals in Sitka, however today a 
majority of the subsistence harvest is of species other than marine 
mammals. Alaska Department Fish and Game reported that in 2013, around 
11 percent of Sitka households used subsistence-caught marine mammals 
(ADF&G, 2023), however this is the most recent data available and there 
has not been a survey since.
    The project is not likely to adversely impact the availability of 
any marine mammal species or stocks that are commonly used for 
subsistence purposes or impact subsistence harvest of marine mammals in 
the region because:
     There is no recent recorded subsistence harvest of marine 
mammals in the area;
     Construction activities are temporary and localized 
primarily within Sitka Channel;
     Construction will not take place during the herring 
spawning season when subsistence species are more active;
     Mitigation measures will be implemented to minimize 
disturbance of marine mammals in the action area; and
     The project will not result in significant changes to 
availability of subsistence resources.
    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, specific to each of the 2 
consecutive years of planned activity, there will not be an unmitigable 
adverse impact on subsistence uses from CBS's activities.

Endangered Species Act

    There are two marine mammals (western DPS Steller sea lion and 
Mexico- North Pacific DPS humpback whale) with the potential to occur 
in the project area that are listed as endangered or threatened under 
the ESA. The NMFS Alaska Regional Office issued a Biological Opinion 
under section 7 of the ESA on the issuance of two IHAs to CBS under 
section 101(a)(5)(D) of the MMPA by the NMFS OPR. The Biological 
Opinion concluded that this action is not likely to jeopardize the 
continued existence of either DPS. In addition, the action authorized 
no take of the Mexico- North Pacific DPS humpback whale and is not 
likely to adversely affect any critical habitat.

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 review our action (i.e., the issuance of an IHA) with respect 
to potential impacts on the human environment.
    This action is consistent with categories of activities identified 
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or 
mortality) of the Companion Manual for NAO 216-6A, which do not 
individually or cumulatively have the potential for significant impacts 
on the quality of the human environment and for which we have not 
identified any extraordinary circumstances that would preclude this 
categorical exclusion. Accordingly, NMFS has determined that the 
issuance of these IHAs qualifies to be categorically excluded from 
further NEPA review.

Authorization

    NMFS has issued two consecutive IHAs to CBS for conducting Seaplane 
Base construction in Sitka, Alaska, starting in July 2024 for Phase I 
and July 2025 for Phase II, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated. 
The issued IHAs can be found at: https://www.fisheries.noaa.gov/action/incidental-take-authorization-city-and-borough-sitkas-seaplane-base-construction-activities.

    Dated: May 6, 2024.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2024-10145 Filed 5-8-24; 8:45 am]
BILLING CODE 3510-22-P