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Notice2025-19008

Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Yakutat Small Boat Harbor Replacement Project in Yakutat, Alaska

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Published

September 30, 2025

Issuing agencies

Commerce DepartmentNational Oceanic and Atmospheric Administration

Abstract

NMFS has received a request from the City & Borough of Yakutat, Alaska (CBY) for authorization to take marine mammals incidental to the Yakutat Small Boat Harbor Replacement Project in Yakutat, Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an incidental harassment authorization (IHA) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, 1-year renewal that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorization and agency responses will be summarized in the final notice of our decision.

Full Text

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<title>Federal Register, Volume 90 Issue 187 (Tuesday, September 30, 2025)</title>
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[Federal Register Volume 90, Number 187 (Tuesday, September 30, 2025)]
[Notices]
[Pages 46812-46834]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-19008]

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XF219]

Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Yakutat Small Boat Harbor
Replacement Project in Yakutat, Alaska

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

ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.

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SUMMARY: NMFS has received a request from the City & Borough of
Yakutat, Alaska (CBY) for authorization to take marine mammals
incidental to the Yakutat Small Boat Harbor Replacement Project in
Yakutat, Alaska. Pursuant to the Marine Mammal Protection Act (MMPA),
NMFS is requesting comments on its proposal to issue an incidental
harassment authorization (IHA) to incidentally take marine mammals
during the specified activities. NMFS is also requesting comments on a
possible one-time, 1-year renewal that could be issued under certain
circumstances and if all requirements are met, as described in Request
for Public Comments at the end of this notice. NMFS will consider
public comments prior to making any final decision on the issuance of
the requested MMPA authorization and agency responses will be
summarized in the final notice of our decision.

DATES: Comments and information must be received no later than October
30, 2025.

ADDRESSES: Comments should be addressed to Permits and Conservation
Division, Office of Protected Resources, National Marine Fisheries
Service and should be submitted via email to <a href="/cdn-cgi/l/email-protection#367f6266184657435a5f5853765859575718515940"><span class="__cf_email__" data-cfemail="d59c8185fba5b4a0b9bcbbb095bbbab4b4fbb2baa3">[email&#160;protected]</span></a>.
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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a> without change. All personal identifying
information (e.g., name, address) voluntarily submitted by the
commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.

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

SUPPLEMENTARY INFORMATION:

Background

The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Section 101(a)(5)(D) of the MMPA (16 U.S.C. 1361 et seq.)
directs the Secretary of Commerce (as delegated to NMFS) to allow, upon
request, the incidental, but not intentional, taking of small numbers
of marine mammals by U.S. citizens who engage in a specified activity
(other than commercial fishing) within a specified geographical region
if 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 (collectively referred to as
``mitigation''); and requirements pertaining to the monitoring and
reporting of the takings. The definitions of all applicable MMPA
statutory terms used above are included in the relevant sections below
and can be found in section 3 of the MMPA (16 U.S.C. 1362) and NMFS
regulations at 50 CFR 216.103.

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 proposed 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 preliminarily determined
that the issuance of the proposed IHA qualifies to be categorically
excluded from further NEPA review.

Summary of Request

On July 8, 2024, NMFS received a request from CBY for an IHA to
take marine mammals incidental to construction activities in Yakutat,
Alaska. Following NMFS' review of the application and extended response
times to questions that were forwarded to CBY, they submitted a revised
version on August 22, 2025. The application was deemed adequate and
complete on September 16, 2025. CBY's request is for take of nine
species of marine mammals by Level B harassment only, and for a subset
of these species, Level A harassment. Neither CBY nor NMFS expect
serious injury or mortality to result from this activity and,
therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

CBY is proposing to replace the existing Yakutat Small Boat Harbor
(YSBH) infrastructure which has been in use for approximately 60 years.
The replacement project will improve accessibility, public safety, and
continue to provide the current level of public service and vessel
mooring in Yakutat, Alaska. The existing gangway, headwalk, mainwalk,
finger, and seaplane floats will be removed. The existing approach dock
will be extended. New modular floats will be installed following
completion of the approach dock extension. Temporary and permanent
piles will secure the floats during and after installation.
In-water pile driving would occur on approximately 54 non-
consecutive days over the course of 1 year. The proposed activities
that have the potential to take marine mammals, by Level A and Level B
harassment, include vibratory removal

[[Page 46813]]

of current steel and timber piles, vibratory installation and removal
of temporary steel pipe piles, vibratory and impact installation of
permanent steel pipe piles, and down-the-hole drilling (DTH) of rock
sockets.

Dates and Duration

The proposed IHA would be valid for the statutory maximum of 1 year
from the date of effectiveness. It would become effective upon written
notification from the applicant to NMFS, but not beginning later than 1
year from the date of issuance or extending beyond 2 years from the
date of issuance. Project construction is anticipated to require
approximately 54 days of in-water work (22 days of vibratory
extraction; 32 days of installation, including impact, vibratory, and
DTH methods) beginning in spring 2026 and would have a duration of
approximately 6 months. Construction would occur based on a 10- or 12-
hour work schedule, with exact timing based upon shift staffing, tide
ranges, and other project scheduling considerations. In-water work,
including pile driving, needs to occur between March 15 and September
30 to avoid hazardous weather conditions.

Specific Geographic Region

The proposed project is located in Yakutat, Alaska with the YSBH
being found within Shipyard Cove. The cove is a sheltered body of water
located on the eastern shore of Monti Bay. It offers a deep-water
anchorage and is part of the larger Yakutat Foreland, an area of
significant biodiversity, supporting over 200 species of birds and
various marine mammals. Yakutat Roads refers to a waterway or channel
in the vicinity of Yakutat, Alaska. It trends northeast between Monti
Bay and Johnstone Passage, about 1 mile northwest of the town of
Yakutat. Northwest of Shipyard Cove and across Yakutat Roads lies Deep
Bay and then Sea Otter Bay which features shallower water.
[GRAPHIC] [TIFF OMITTED] TN30SE25.006

Figure 1--Yakutat Small Boat Harbor Replacement Project

Detailed Description of the Specified Activity

CBY proposed to replace the existing YSBH infrastructure.
Demolition of the existing structure would consist of removing all
existing timber headwalk floats, mainwalk floats, and finger floats
with the exception of the seaplane haulout ramp and work float, which
would be removed and salvaged for refurbishment and reinstallation. The
existing steel gangway and a small portion of the current timber
approach dock would also be removed. Existing harbor floats are
primarily moored with timber piles and a small number of steel piles.
Piles would be removed with a vibratory hammer to facilitate removal of
the floats. Quantities and methods for pile removal are detailed within
table 1.
Installation of new harbor infrastructure would begin at the
existing approach dock and extend offshore. A new 20-foot (6-meter)
approach dock extension would be installed consisting of a steel
substructure with timber stringers and timber decking, supported by a
total of four 12.75-in (32.3 centimeters (cm)) diameter steel piles.
All piles would be driven with a vibratory hammer from a barge-based
crane. Following vibratory installation, the piles would be proofed
with an impact hammer to achieve design bearing capacity. The
contractor would install temporary template piles (up to 24-in (50.8-
cm) diameter pipe piles or equivalent) to facilitate accurate
installation of permanent piles, with temporary piles being removed
following permanent pile installation. Temporary piles would be
installed and removed using vibratory methods only.
New floats would be mobilized to site on a materials barge and
offloaded

[[Page 46814]]

directly into the water. Individual float modules would be connected
into manageable sections for installation. To ensure floats are
installed accurately, the contractor would install up to 15 temporary
template piles (up to 24-in diameter pipe piles or equivalent) to moor
the floats in the proper position prior to the installation of the
permanent piles. Temporary piles would be installed and removed using
vibratory methods only. Once floats are in position, permanent float
piles would be driven with a vibratory hammer to the greatest extent
possible to achieve the specified minimum embedment of 20 feet (6.09 m)
for 12.75-in piles, 25 feet (7.6 m) for 16-in (40.6 cm) piles or 40
feet (12.2 m) for 24-in piles. If insufficient overburden exists, pile
installation via rock sockets would be employed as described below.
Due to the suspected presence of near-surface bedrock within the
project site, some permanent float piles may require drilled rock
sockets if the minimum specified pile embedment is not obtained. If
determined to be necessary, sockets a minimum of 8 feet deep would be
drilled into bedrock through the pile shaft to the width of the
associated pile via DTH drilling methods. The pile would be drawn down
into the DTH drilled socket through the drilling action. Prior to DTH
drilling, an impact hammer would be used to seat (secure) the pile tip
into the bedrock to ensure the pile does move during the drilling
operations.

Table 1--Number and Type of Piles To Be Installed and Removed
--------------------------------------------------------------------------------------------------------------------------------------------------------
Project Max piles Minutes/ strikes Days of Avg. piles
Pile size and type Construction method total per day per pile effort per day
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
Steel Pile Removal (up to 16'').............. Vibratory.............................. 14 15 5-15/NA 2 7
Timber Pile Removal (up to 12'')............. Vibratory.............................. 65 15 5-15/NA 10 7
--------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Trestle Template Pile (up to 24'' steel pipe Vibratory.............................. 8 4 10-20/NA 2 4
pile or equiv.).
Float Template Pile (up to 24'' steel pipe or Vibratory.............................. 15 5 10-20/NA 8 2
equiv.).
--------------------------------------------------------------------------------------------------------------------------------------------------------
New Pile Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Permanent Trestle Steel Pipe Pile (12.75'').. Vibratory.............................. 4 4 10-20/NA 2 2
Impact \1\............................. 4 4 10-30/500 2
Permanent Float Steel Pipe Pile (up to 24''). Vibratory.............................. 91 5 10-20/NA 30 3
Impact................................. 91 5 10-30/1000 3
DTH Drilling \2\....................... 30 2 60-180/180 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Vibratory hammer would be the primary pile installation method. Piles would be proofed with an impact hammer to achieve design bearing capacity.
\2\ Vibratory hammer would be used whenever feasible for float pile installation. If minimum pile embedment is not achieved due to bedrock, the pile
would be impacted to seat the pile into the bedrock and socketed via DTH drilling methods.

Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).

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; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 2 lists all species or stocks for which take is expected and
proposed to be 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 proposed
to be authorized here, PBR and annual serious injury and mortality (M/
SI) 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. Marine Mammal SARs. All values presented in table 2 are the
most recent available at the time of publication (including from the
draft 2024 SARs) and are available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.

[[Page 46815]]

Table 2--Species \1\ With Estimated Take From the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/ MMPA status; Stock abundance (CV;
Common name Scientific name Stock strategic (Y/N) Nmin; most recent PBR Annual M/
\2\ abundance survey) \3\ SI \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Artiodactyla--Infraorder Cetacea--Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
Gray whale...................... Eschrichtius robustus.. E. North Pacific....... -,-,N 26,960 (0.05, 25,849, 801 131
2016).
Family Balaenopteridae (rorquals):
Humpback whale.................. Megaptera novaeangliae. Hawai[revaps]i \5\..... -,-,N 11,278 (0.56, 7,265, 127 27.09
2020).
Mex-North Pacific \6\.. T, D, Y 918 (N/A, N/A, 2006).. UND 0.57
--------------------------------------------------------------------------------------------------------------------------------------------------------
Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
Beluga whale.................... Delphinapterus leucas.. Cook Inlet............. E, D, Y 331(0.076 311, 2022) 0 0
\10\.
Killer whale.................... Orcinus orca........... E North Pacific Alaska -,-,N 1,920, (N/A, 1,920, 19 1.3
Resident. 2019) \7\.
ENP Gulf of Alaska, -,-,N 587 (N/A, 587, 2012).. 5.9 0.8
Aleutian Islands, and
Bering Sea Transient
stock.
West Coast Transient... -,-,N 349 (N/A, 349, 2018).. 3.5 0.4
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... Yakutat/SE AK Offshore. -,-,N N/A (N/A, N/A, 1997).. UND 22.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order--Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
sea lions):
California sea lion............. Zalophus californianus. U.S.................... -,-,N 257,606 (N/A, 233,515, 14,011 >321
2014).
Northern fur seal............... Callorhinus ursinus.... Eastern Pacific........ -,D,Y 626,618 (0.2, 530,376, 11,403 373
2019).
Steller sea lion................ Eumetopias jubatus..... Eastern................ -,-,N 36,308 (N/A, 36,308, 2,178 93.2
2022) \8\.
Western................ E, D, Y................ 49,837 (N/A, 299................... 267
49,837, 2022) \9\
Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... Prince William Sound... -,-,N 44,756 (N/A, 41,776, 1,253 413
2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>; Committee on Taxonomy, 2022).
\2\ 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.
\3\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region</a>. CV is coefficient of variation; N min is the minimum estimate of stock abundance. In some cases, CV is not applicable.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
\5\ The best available abundance estimate for this stock is not considered representative of the entire stock as surveys were limited to a small portion
of the stock's range. Based upon this estimate and the Nmin, the PBR value is likely negatively biased for the entire stock.
\6\ Abundance estimates are based upon data collected more than 8 years ago and and, therefore, current estimates are considered unknown. SAR in 2022
following North Pacific humpback whale stock structure changes.
\7\ Abundance estimates are based upon data collected more than 8 years ago and, therefore, current estimates are considered unknown.
\8\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the U.S.
only.
\9\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the U.S.
only. The overall Nmin is 73,211 and overall PBR is 439.
\10\ The Yakutat Bay beluga whales are a subset of the Cook Inlet beluga whale stock which are genetically and geographically separated, and have been
defined as a small and resident group.

As indicated above, all 9 species (with 13 managed stocks) in table
2 temporally and spatially co-occur with the activity to the degree
that take is reasonably likely to occur.
In addition to what is included in sections 3 and 4 of the IHA
application, and NMFS' website, further detail informing our analysis
on the regional occurrence for select species of particular or unique
vulnerability (i.e., information regarding ESA listed species) is
provided below.

Gray Whale

The migration corridor for Eastern North Pacific (ENP) stock of
gray whales is along the nearshore Gulf of Alaska. One satellite
tagging study of a migrating ENP gray whale found that the tagged whale
travelled relatively close to shore (within 23 km on average) but
primarily took the most direct route outside of embayments (Urban-
Ramirez et al., 2021). A migratory Biologically Important Area (BIA)
for the gray whale exists for the months of January, March, April, May,
November and December. The Alaska Department of Fish and Game wildlife
viewing recommendations for Yakutat indicate that gray whales can be
spotted in Yakutat Bay (ADFG 2024b).

[[Page 46816]]

A marine mammal monitoring report from the Ocean Cape Seafoods Dock
Fender Repairs project in Monti Bay did not report any occurrences of
gray whales from October 18 to October 21, 2016 (Bacon et al. 2016).

Humpback Whale

Two stocks of humpback whales could be found in the project area.
These include the Hawai'i Stock (not ESA-listed) and the Mexico-North
Pacific Stock (ESA-threatened). Although humpbacks seasonally migrate,
they are observed in inner and outer Resurrection Bay regularly
throughout the summer season (May through August) and may venture into
the outer bay year-round (McCaslin, 2019; GBIF, 2022a). There are no
designated critical habitats or biologically important areas for
humpback whales in the project area. In the project area it is assumed
that 2.4 percent of the animals are designated to the Mexico-North
Pacific stock, and the remaining are designated to the Hawai'i stock
(Wade 2021).

Beluga Whale

Beluga whales in Yakutat Bay represent a small resident population
of likely less than 20 individuals (Young et al. 2023). The core area
for these animals appears to be Disenchantment Bay, at the far
northeast end of Yakutat Bay, located between four actively calving
tidewater glaciers (Castellote et al. 2015). Disenchantment Bay is
located approximately 51 km north of Yakutat. Local and traditional
ecological knowledge suggests that the Yakutat Bay beluga whales have
been present in the bay continuously since at least the 1930s (Lucey et
al. 2015), and modern genetic analysis suggests that they are
genetically isolated from Cook Inlet beluga whales (Young et al. 2023).
Thus, the Yakutat Bay beluga whales are not included in the endangered
Cook Inlet Distinct Population Segment (DPS) of beluga whales under the
Endangered Species Act. However, when Cook Inlet beluga whales were
designated as depleted under the MMPA there was insufficient
information to identify Yakutat Bay beluga whales as a separate
population, and they were included in the Cook Inlet Stock (Young et
al. 2023).

Killer Whale

Seven stocks of the killer whale are found in Alaskan waters; the
ENP Alaska Resident stock; the ENP Northern Resident stock; the ENP
Gulf of Alaska, Aleutian Islands, and Bering Sea Transient stock; the
AT1 Transient stock; the West Coast Transient stock, the ENP Southern
Resident stock, and the ENP Offshore stock. All of these stocks are
considered non-strategic, except for the AT1 Transient and endangered
ENP Southern Resident stocks (Muto et al. 2021).
The ENP Alaska Resident stock; ENP Gulf of Alaska, Aleutian
Islands, and Bering Sea Transient stock; and West Coast Transient stock
killer whales may be found in the construction impacts area (Muto et
al. 2021). The ENP Alaska Resident stock is found between Southeast
Alaska and the Bering Sea (Muto et al. 2021). The ENP Gulf of Alaska,
Aleutian Islands, and Bering Sea Transient stock also occurs between
Southeast Alaska and the Bering Sea. The West Coast Transient stock
ranges from California to Southeast Alaska. Most of the transient
killer whales sighted in the inland waters of Southeast Alaska are West
Coast Transients. They may occasionally associate with Gulf of Alaska
transients but are not known to interbreed.
Records of killer whales in the Global Biodiversity Information
Facility (GBIF) show sightings nearshore from the Yakutat and Malaspina
forelands, but not within Yakutat Bay. The Alaska Department of Fish
and Game wildlife viewing recommendations for Yakutat indicates that
killer whales can be spotted in Yakutat Bay (ADFG 2024b). A marine
mammal monitoring report from the Ocean Cape Seafoods Dock Fender
Repairs project in Monti Bay did not report any occurrences of killer
whales from October 18 to October 21, 2016 (Bacon et al. 2016).

Harbor Porpoise

The harbor porpoise frequents nearshore waters and coastal
embayments throughout their range, including bays, harbors, estuaries,
and fjords less than 650 feet (198 m) deep (NMFS 2022b). Records of
harbor porpoises in the GBIF show 44 occurrences reported by the public
and agencies within and immediately offshore of Yakutat Bay in the past
twenty years (GBIF 2024).
A marine mammal monitoring report from the Ocean Cape Seafoods Dock
Fender Repairs project in Monti Bay reported three occurrences of
harbor porpoises with an estimated average group size of two
individuals from 18 October to 21 October 2016 (Bacon et al. 2016).
Harbor porpoises would be expected to be among the most frequently
encountered marine mammal species in the project area.

California Sea Lion

California sea lions do not have established or permanent haulouts
in Alaska; however, individual animals are occasionally sighted along
the coast. There are no records of California sea lions in the Global
Biodiversity Information Facility nearshore or offshore of the eastern
Gulf of Alaska coast from Lituya Bay to Icy Bay (GBIF 2024).
A marine mammal monitoring report from the Ocean Cape Seafoods Dock
Fender Repairs project in Monti Bay reported one occurrence of a single
unidentified otariid from 18 October to 21 October 2016 (Bacon et al.
2016).

Steller Sea Lion

The closest documented Steller sea lion haulouts are located at
Situk, approximately 30 km southeast of Yakutat, and Haenke,
approximately 48 km north of Yakutat. A marine mammal monitoring report
from the Ocean Cape Seafoods Dock Fender Repairs project in Monti Bay
reported a single occurrence of an unidentified otariid, presumably a
Steller sea lion, entering the project's exclusion zone between 18
October 18 and October 21, 2016 (Bacon et al. 2016).
The western DPS stock (ESA-endangered) of Steller sea lion may
occur in limited numbers in the project area. Womble et al. (2009)
characterized Steller sea lion distribution in southeast Alaska in
relation to seasonally available prey resources. It is estimated that
8.2 percent of the animals found near Yakutat could be from the western
DPS.

Northern Fur Seal

Northern fur seals are typically found in offshore waters outside
of the breeding season (May through November), although females and
young males may be found closer to shore as they move to southern
waters. Northern fur seals in Alaska are primarily located in the
Pribilof Islands in the Bering Sea, with significant breeding
populations on St. Paul Island and St. George Island. A smaller
breeding colony can also be found on Bogoslof Island. During the
winter, they migrate into the open ocean, ranging south into the Gulf
of Alaska and even as far as California. In Southeast Alaska and
British Columbia, they are known to occasionally haul out at sea lion
rookeries (Carretta et al. 2022).
Records of northern fur seals in the GBIF show a single occurrence
from a preserved specimen reported near the continental shelf break
outside Yakutat Bay in 1892 (GBIF 2024).
A marine mammal monitoring report from the Ocean Cape Seafoods Dock
Fender Repairs project in Monti Bay reported one occurrence of a single

[[Page 46817]]

unidentified Otariid from October 18-21, 2016 (Bacon et al. 2016).

Harbor Seal

Twelve stocks of harbor seals have been identified in Alaska,
ranging from the Dixon Entrance in Southeast Alaska to Bristol Bay and
the Aleutian Islands (Figure 10). Harbor seals found within the range
of effects from project construction are likely from the Prince William
Sound stock (Muto et al. 2021) which ranges from Elizabeth Island off
the southwest tip of the Kenai Peninsula to Cape Fairweather, including
Prince William Sound, the Copper River Delta, Icy Bay, and Yakutat Bay.
The current 8-year estimate of the Prince William Sound population
trend is-200 seals per year, with a probability that the stock is
decreasing of 0.648. There has been limited survey effort outside of
glacial habitats in recent years and, thus, the most recent abundance
estimates have larger credible intervals.
The nearest harbor seal haulout is located approximately 8.3 km
from Yakutat and is not considered to be a major haulout.
Records of harbor seals in the GBIF show 30 occurrences reported by
the public and agencies within and immediately offshore of Yakutat Bay
in the past twenty years (GBIF 2024).
A marine mammal monitoring report from the Ocean Cape Seafoods Dock
Fender Repairs project in Monti Bay did not report any occurrences of
harbor seals from 18 October to 21 October 2016 (Bacon et al. 2016).

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.). Generalized hearing ranges were
chosen based on the ~65 decibel (dB) threshold from composite
audiograms, previous analyses in NMFS (2018), and/or data from Southall
et al. (2007) and Southall et al. (2019). We note that the names of two
hearing groups and the generalized hearing ranges of all marine mammal
hearing groups have been recently updated (NMFS, 2024) as reflected
below in table 3.

Table 3--Marine Mammal Hearing Groups
[NMFS, 2024]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 36 kHz.
whales).
High-frequency (HF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
Very High-frequency (VHF) cetaceans 200 Hz to 165 kHz.
(true porpoises, Kogia, river
dolphins, Cephalorhynchid,
Lagenorhynchus cruciger & L.
australis).
Phocid pinnipeds (PW) (underwater) 40 Hz to 90 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 68 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges may not be as broad. Generalized hearing range
chosen based on approximately 65 dB threshold from composite
audiogram, previous analysis in NMFS (2018), and/or data from Southall
et al. (2007) and Southall et al. (2019). Additionally, animals are
able to detect very loud sounds above and below that ``generalized''
hearing range.

For more detail concerning these groups and associated frequency
ranges, please see NMFS (2024) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their
Habitat

This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take of Marine Mammals section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take of Marine Mammals section, and the Proposed Mitigation
section, to draw conclusions regarding the likely impacts of these
activities on the reproductive success or survivorship of individuals
and whether those impacts are reasonably expected to, or reasonably
likely to, adversely affect the species or stock through effects on
annual rates of recruitment or survival.
Acoustic effects on marine mammals during the specified activity
can occur from impact and vibratory pile driving as well as DTH. The
effects of underwater noise from CBY's proposed activities have the
potential to result in Level A or Level B harassment of marine mammals
in the action area.

Description of Sound Sources

The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far. The sound level of an area is defined by the
total acoustical energy being generated by known and unknown sources.
These sources may include physical (e.g., waves, wind, precipitation,
earthquakes, ice, and atmospheric sound), biological (e.g., sounds
produced by marine mammals, fish, and invertebrates), and anthropogenic
sound (e.g., vessels, dredging, aircraft, and construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor and is frequency-dependent. As a result of the dependence on many
varying factors, ambient sound levels can be expected to vary widely
over both coarse and fine spatial and temporal scales. Sound levels at
a given frequency and location can vary by 10 to 20 dB from day to day
(Richardson et al., 1995). The result is that, depending on the source
type and its

[[Page 46818]]

intensity, sound from the specified activity may be a negligible
addition to the local environment or could form a distinctive signal
that may affect marine mammals.
In-water construction activities associated with the project would
include vibratory pile removal, impact and vibratory pile driving, and
DTH. The sounds produced by these activities fall into one of two
general sound types: impulsive and non-impulsive. Impulsive sounds
(e.g., explosions, gunshots, sonic booms, and impact pile driving) are
typically transient, brief (less than 1 second), broadband, and consist
of high peak sound pressure with rapid rise time and rapid decay (ANSI,
1986; NIOSH, 1998; ANSI, 2005; NMFS, 2018a). Non-impulsive sounds
(e.g., aircraft, machinery operations such as drilling or dredging,
vibratory pile driving, and active sonar systems) can be broadband,
narrowband or tonal, brief or prolonged (continuous or intermittent),
and typically do not have the high peak sound pressure with raid rise/
decay time that impulsive sounds do (ANSI, 1995; NIOSH, 1998; NMFS,
2018a). The distinction between these two sound types is important
because they have differing potential to cause physical effects,
particularly with regard to hearing (e.g., Ward 1997 in Southall et
al., 2007).
CBY proposes to use vibratory hammers to remove steel piles,
vibratory and impact pile driving to install new steel pipe piles, and
DTH for a subset of installed piles to reach full depth. Impact hammers
operate by repeatedly dropping a heavy piston onto a pile to drive the
pile into the substrate. Sound generated by impact hammers is
characterized by rapid rise times and high peak levels, a potentially
injurious combination (Hastings and Popper, 2005). Vibratory hammers
install piles by vibrating them and allowing the weight of the hammer
to push them into the sediment. Vibratory hammers produce significantly
less sound than impact hammers. Peak sound pressure levels (SPLs) may
be 180 dB or greater, but are generally 10 to 20 dB lower than SPLs
generated during impact pile driving of the same-sized pile (Oestman et
al., 2009). Rise time is slower, reducing the probability and severity
of injury, and sound energy is distributed over a greater amount of
time (Nedwell and Edwards, 2002; Carlson et al., 2005).
A DTH hammer is essentially a drill bit that drills through the
bedrock using a rotating function like a normal drill, in concert with
a hammering mechanism operated by a pneumatic (or sometimes hydraulic)
component integrated into the DTH hammer to increase speed of progress
through the substrate (i.e., it is similar to a ``hammer drill'' hand
tool). The sounds produced by the DTH method contain both a continuous
non-impulsive component from the drilling action and an impulsive
component from the hammering effect. Therefore, we treat DTH systems as
both impulsive and non-impulsive sound source types simultaneously.
The likely or possible impacts of CBY's proposed activity on marine
mammals could involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of equipment and personnel; however, any impacts to marine
mammals are expected to be primarily acoustic in nature. Acoustic
stressors include effects of heavy equipment operation during pile
installation and removal.

Acoustic Effects

The introduction of anthropogenic noise into the aquatic
environment from pile driving and removal is the means by which marine
mammals may be harassed from CBY's specified activity. In general,
animals exposed to natural or anthropogenic sound may experience
behavioral, physiological, and/or physical effects, ranging in
magnitude from none to severe (Southall et al., 2007, 2019). In
general, exposure to pile driving noise has the potential to result in
behavioral reactions (e.g., avoidance, temporary cessation of foraging
and vocalizing, and changes in dive behavior) and, in limited cases, an
auditory threshold shift (TS). Exposure to anthropogenic noise can also
lead to non-observable physiological responses such an increase in
stress hormones. Additional noise in a marine mammal's habitat can mask
acoustic cues used by marine mammals to carry out daily functions such
as communication and predator and prey detection. The effects of pile
driving noise on marine mammals are dependent on several factors,
including, but not limited to, sound type (e.g., impulsive vs. non-
impulsive), the species, age and sex class (e.g., adult male vs. mom
with calf), duration of exposure, the distance between the pile and the
animal, received levels, behavior at time of exposure, and previous
history with exposure (Wartzok et al., 2004; Southall et al., 2007).
Here we discuss physical auditory effects (TSs) followed by behavioral
effects and potential impacts on habitat.
NMFS defines a noise-induced TS as a change, usually an increase,
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS, 2018, 2024). The amount of TS is customarily expressed in
dB. A TS can be permanent or temporary. As described in NMFS (2018,
2024), there are numerous factors to consider when examining the
consequence of TS, including, but not limited to, the signal temporal
pattern (e.g., impulsive or non-impulsive), likelihood an individual
would be exposed for a long enough duration or to a high enough level
to induce a TS, the magnitude of the TS, time to recovery (seconds to
minutes or hours to days), the frequency range of the exposure (i.e.,
spectral content), the hearing and vocalization frequency range of the
exposed species relative to the signal's frequency spectrum (i.e., how
animal uses sound within the frequency band of the signal; e.g.,
Kastelein et al., 2014), and the overlap between the animal and the
source (e.g., spatial, temporal, and spectral).
Auditory Injury (AUD INJ) and Permanent Threshold Shift (PTS)--NMFS
defines AUD INJ as ``damage to the inner ear that can result in
destruction of tissue . . . which may or may not result in PTS'' (NMFS,
2024). NMFS defines PTS as a permanent, irreversible increase in the
threshold of audibility at a specified frequency or portion of an
individual's hearing range above a previously established reference
level (NMFS, 2024). PTS does not generally affect more than a limited
frequency range, and an animal that has incurred PTS has incurred some
level of hearing loss at the relevant frequencies; typically, animals
with PTS are not functionally deaf (Au and Hastings, 2008; Finneran,
2016). Available data from humans and other terrestrial mammals
indicate that a 40-dB threshold shift approximates PTS onset (see Ward
et al., 1958, 1959, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et
al., 1996; Henderson et al., 2008). PTS levels for marine mammals are
estimates, as with the exception of a single study unintentionally
inducing PTS in a harbor seal (Kastak et al., 2008), there are no
empirical data measuring PTS in marine mammals largely due to the fact
that, for various ethical reasons, experiments involving anthropogenic
noise exposure at levels inducing PTS are not typically pursued or
authorized (NMFS, 2018).
Temporary Threshold Shift (TTS)--TTS is a temporary, reversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS, 2018). Based on data from

[[Page 46819]]

cetacean TTS measurements (Southall et al., 2007), a TTS of 6 dB is
considered the minimum TS clearly larger than any day-to-day or
session-to-session variation in a subject's normal hearing ability
(Schlundt et al., 2000; Finneran et al., 2000, 2002). As described in
Finneran (2015), marine mammal studies have shown the amount of TTS
increases with cumulative sound exposure level (SEL<INF>cum</INF>) in
an accelerating fashion: At low exposures with lower SEL<INF>cum,</INF>
the amount of TTS is typically small and the growth curves have shallow
slopes. At exposures with higher SEL<INF>cum</INF>, the growth curves
become steeper and approach linear relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in the Masking
section, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Many studies have examined noise-induced hearing loss in marine
mammals (see Finneran (2015) and Southall et al. (2019) for summaries).
TTS is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter, 2013). While experiencing TTS, the hearing
threshold rises, and a sound must be at a higher level in order to be
heard. In terrestrial and marine mammals, TTS can last from minutes or
hours to days (in cases of strong TTS). In many cases, hearing
sensitivity recovers rapidly after exposure to the sound ends. For
cetaceans, published data on the onset of TTS are limited to captive
bottlenose dolphin (Tursiops truncatus), beluga whale, harbor porpoise,
and Yangtze finless porpoise (Neophocoena asiaeorientalis) (Southall et
al., 2019). For pinnipeds in water, measurements of TTS are limited to
harbor seals, elephant seals (Mirounga angustirostris), bearded seals
(Erignathus barbatus) and California sea lions (Kastak et al., 1999,
2007; Kastelein et al., 2019b, 2019c, 2021, 2022a, 2022b; Reichmuth et
al., 2019; Sills et al., 2020). TTS was not observed in spotted (Phoca
largha) and ringed (Pusa hispida) seals exposed to single airgun
impulse sounds at levels matching previous predictions of TTS onset
(Reichmuth et al., 2016). These studies examine hearing thresholds
measured in marine mammals before and after exposure to intense or
long-duration sound exposures. The difference between the pre-exposure
and post-exposure thresholds can be used to determine the amount of
threshold shift at various post-exposure times.
The amount and onset of TTS depends on the exposure frequency.
Sounds at low frequencies, well below the region of best sensitivity
for a species or hearing group, are less hazardous than those at higher
frequencies, near the region of best sensitivity (Finneran and
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are
higher compared to those in the region of best sensitivity (i.e., a low
frequency noise would need to be louder to cause TTS onset when TTS
exposure level is higher), as shown for harbor porpoises and harbor
seals (Kastelein et al., 2019a, 2019c). Note that in general, harbor
seals and harbor porpoises have a lower TTS onset than other measured
pinniped or cetacean species (Finneran, 2015). In addition, TTS can
accumulate across multiple exposures, but the resulting TTS would be
less than the TTS from a single, continuous exposure with the same SEL
(Mooney et al., 2009; Finneran et al., 2010; Kastelein et al., 2014,
2015). This means that TTS predictions based on the total, cumulative
SEL would overestimate the level of TTS from intermittent exposures,
such as sonars and impulsive sources. Nachtigall et al. (2018) describe
measurements of hearing sensitivity of multiple odontocete species
(bottlenose dolphin, harbor porpoise, beluga, and false killer whale
(Pseudorca crassidens)) when a relatively loud sound was preceded by a
warning sound. These captive animals were shown to reduce hearing
sensitivity when warned of an impending intense sound. Based on these
experimental observations of captive animals, the authors suggest that
wild animals may dampen their hearing during prolonged exposures or if
conditioned to anticipate intense sounds. Another study showed that
echolocating animals (including odontocetes) might have anatomical
specializations that might allow for conditioned hearing reduction and
filtering of low-frequency ambient noise, including increased stiffness
and control of middle ear structures and placement of inner ear
structures (Ketten et al., 2021). Data available on noise-induced
hearing loss for mysticetes are currently lacking (NMFS, 2018).
Additionally, the existing marine mammal TTS data come from a limited
number of individuals within these species.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals, and there is no PTS data for cetaceans, but such
relationships are assumed to be similar to those in humans and other
terrestrial mammals. PTS typically occurs at exposure levels at least
several decibels above that inducing mild TTS (e.g., a 40-dB threshold
shift approximates PTS onset (Kryter et al., 1966; Miller, 1974), while
a 6-dB threshold shift approximates TTS onset (Southall et al., 2007,
2019). Based on data from terrestrial mammals, a precautionary
assumption is that the PTS thresholds for impulsive sounds (such as
impact pile driving pulses as received close to the source) are at
least 6 dB higher than the TTS threshold on a peak-pressure basis and
PTS cumulative sound exposure level thresholds are 15 to 20 dB higher
than TTS cumulative sound exposure level thresholds (Southall et al.,
2007, 2019). Given the higher level of sound or longer exposure
duration necessary to cause PTS as compared with TTS, it is
considerably less likely that PTS could occur.
Activities for this project include impact pile driving, vibratory
pile driving and vibratory removal, and DTH. There would likely be
pauses in activities producing the sound during each day. Given these
pauses and the fact that many marine mammals are likely moving through
the project areas and not remaining for extended periods of time, the
potential for TS declines.
Behavioral Harassment--Exposure to noise from pile driving also has
the potential to behaviorally disturb marine mammals. Generally
speaking, NMFS considers a behavioral disturbance that rises to the
level of harassment under the MMPA a non-minor response--in other
words, not every response qualifies as behavioral disturbance, and for
responses that do, those of a higher level, or accrued across a longer
duration, have the potential to affect foraging, reproduction, or
survival. Behavioral disturbance may include a variety of effects,
including subtle

[[Page 46820]]

changes in behavior (e.g., minor or brief avoidance of an area or
changes in vocalizations), more conspicuous changes in similar
behavioral activities, and more sustained and/or potentially severe
reactions, such as displacement from or abandonment of high-quality
habitat. Behavioral responses may include changing durations of
surfacing and dives, changing direction and/or speed; reducing/
increasing vocal activities; changing/cessation of certain behavioral
activities (such as socializing or feeding); eliciting a visible
startle response or aggressive behavior (such as tail/fin slapping or
jaw clapping); avoidance of areas where sound sources are located.
Pinnipeds may increase their haul out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006).
Behavioral responses to sound are highly variable and context-
specific and any reactions depend on numerous intrinsic and extrinsic
factors (e.g., species, state of maturity, experience, current
activity, reproductive state, auditory sensitivity, time of day), as
well as the interplay between factors (e.g., Richardson et al., 1995;
Wartzok et al., 2004; Southall et al., 2007, 2019; Weilgart, 2007;
Archer et al., 2010). Behavioral reactions can vary not only among
individuals but also within an individual, depending on previous
experience with a sound source, context, and numerous other factors
(Ellison et al., 2012), and can vary depending on characteristics
associated with the sound source (e.g., whether it is moving or
stationary, number of sources, distance from the source). In general,
pinnipeds seem more tolerant of, or at least habituate more quickly to,
potentially disturbing underwater sound than do cetaceans, and
generally seem to be less responsive to exposure to industrial sound
than most cetaceans. Please see Appendices B and C of Southall et al.
(2007) and Gomez et al. (2016) for reviews of studies involving marine
mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2004). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure.
As noted above, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; Wartzok et al., 2004; National Research Council (NRC), 2005).
Controlled experiments with captive marine mammals have showed
pronounced behavioral reactions, including avoidance of loud sound
sources (Ridgway et al., 1997; Finneran et al., 2003). Observed
responses of wild marine mammals to loud pulsed sound sources (e.g.,
seismic airguns) have been varied but often consist of avoidance
behavior or other behavioral changes (Richardson et al., 1995; Morton
and Symonds, 2002; Nowacek et al., 2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et
al., 2004; Goldbogen et al., 2013a, 2013b). Variations in dive behavior
may reflect interruptions in biologically significant activities (e.g.,
foraging) or they may be of little biological significance. The impact
of an alteration to dive behavior resulting from an acoustic exposure
depends on what the animal is doing at the time of the exposure and the
type and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. However, acoustic and movement bio-logging tools have been
used in some cases, to infer responses of feeding to anthropogenic
noise. For example, Blair et al. (2016) reported significant effects on
humpback whale foraging behavior in Stellwagen Bank in response to ship
noise including slower descent rates, and fewer side-rolling events per
dive with increasing ship nose. In addition, Wisniewska et al. (2018)
reported that tagged harbor porpoises demonstrated fewer prey capture
attempts when encountering occasional high-noise levels resulting from
vessel noise as well as more vigorous fluking, interrupted foraging,
and cessation of echolocation signals observed in response to some
high-noise vessel passes.
In response to playbacks of vibratory pile driving sounds, captive
bottlenose dolphins showed changes in target detection and number of
clicks used for a trained echolocation task (Branstetter et al., 2018).
Similarly, harbor porpoises trained to collect fish during playback of
impact pile driving sounds also showed potential changes in behavior
and task success, though individual differences were prevalent
(Kastelein et al., 2019d). As for other types of behavioral response,
the frequency, duration, and temporal pattern of signal presentation,
as well as differences in species sensitivity, are likely contributing
factors to differences in response in any given circumstance (e.g.,
Croll et al., 2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko
et al., 2007). A determination of whether foraging disruptions incur
fitness consequences would require information on or estimates of the
energetic requirements of the affected individuals and the
relationships among prey availability, foraging effort and success, and
the life history stage(s) of the animal.
Variations in respiration naturally vary with different behaviors
and alterations to breathing rate as a function of acoustic exposure
can be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response. Various studies have shown that respiration rates may
either be unaffected or could increase, depending on the species and
signal characteristics, again highlighting the importance in
understanding species differences in the

[[Page 46821]]

tolerance of underwater noise when determining the potential for
impacts resulting from anthropogenic sound exposure (e.g., Kastelein et
al., 2001, 2005, 2006; Gailey et al., 2007). For example, harbor
porpoise respiration rate increased in response to pile driving sounds
at and above a received broadband SPL of 136 dB (zero-peak SPL: 151 dB
(referenced to 1 micropascal (re 1 [mu]Pa)); SEL of a single strike:
127 dB re 1 [mu]Pa\2\-s) (Kastelein et al., 2013).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
are known to change direction--deflecting from customary migratory
paths--in order to avoid noise from seismic surveys (Malme et al.,
1984). Avoidance may be short-term, with animals returning to the area
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996;
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007).
Longer-term displacement is possible, however, which may lead to
changes in abundance or distribution patterns of the affected species
in the affected region if habituation to the presence of the sound does
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann
et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996; Bowers et al., 2018). The result of a flight response
could range from brief, temporary exertion and displacement from the
area where the signal provokes flight to, in extreme cases, marine
mammal strandings (England et al., 2001). However, it should be noted
that response to a perceived predator does not necessarily invoke
flight (Ford and Reeves, 2008), and whether individuals are solitary or
in groups may influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fishes and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a 5-day period did not cause any sleep
deprivation or stress effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than 1 day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive (i.e., meaningful) behavioral reactions and multi-day
anthropogenic activities. For example, just because an activity lasts
for multiple days does not necessarily mean that individual animals are
either exposed to activity-related stressors for multiple days or,
further, exposed in a manner resulting in sustained multi-day
substantive behavioral responses.
Stress Responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress would last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker, 2000;
Romano et al., 2002b) and, more rarely, studied in wild populations
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found
that noise reduction from reduced ship traffic in the Bay of Fundy was
associated with decreased stress in North Atlantic right whales. These
and other studies lead to a reasonable expectation that some marine
mammals would experience physiological stress responses upon exposure
to acoustic stressors and that it is possible that some of these would
be classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2003), however
distress is an unlikely result of this project based on observations of
marine mammals during previous, similar projects in the area.
Auditory Masking--Since many marine mammals rely on sound to find
prey, moderate social interactions, and facilitate mating (Tyack,
2008), noise

[[Page 46822]]

from anthropogenic sound sources can interfere with these functions,
but only if the noise spectrum overlaps with the hearing sensitivity of
the receiving marine mammal (Southall et al., 2007; Clark et al., 2009;
Hatch et al., 2012). Chronic exposure to excessive, though not high-
intensity, noise could cause masking at particular frequencies for
marine mammals that utilize sound for vital biological functions (Clark
et al., 2009). Acoustic masking is when other noises such as from human
sources interfere with an animal's ability to detect, recognize, or
discriminate between acoustic signals of interest (e.g., those used for
intraspecific communication and social interactions, prey detection,
predator avoidance, navigation) (Richardson et al., 1995; Erbe et al.,
2016). Therefore, under certain circumstances, marine mammals whose
acoustical sensors or environment are being severely masked could also
be impaired from maximizing their performance fitness in survival and
reproduction. The ability of a noise source to mask biologically
important sounds depends on the characteristics of both the noise
source and the signal of interest (e.g., signal-to-noise ratio,
temporal variability, direction), in relation to each other and to an
animal's hearing abilities (e.g., sensitivity, frequency range,
critical ratios, frequency discrimination, directional discrimination,
age or TTS hearing loss), and existing ambient noise and propagation
conditions (Hotchkin and Parks, 2013).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003) or vocalizations (Foote et al., 2004),
respectively, while North Atlantic right whales (Eubalaena glacialis)
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007). Fin whales have also been documented
lowering the bandwidth, peak frequency, and center frequency of their
vocalizations under increased levels of background noise from large
vessels (Castellote et al., 2012). Other alterations to communication
signals have also been observed. For example, gray whales, in response
to playback experiments exposing them to vessel noise, have been
observed increasing their vocalization rate and producing louder
signals at times of increased outboard engine noise (Dahlheim and
Castellote, 2016). Alternatively, animals may cease sound production
during production of aversive signals (Bowles et al., 1994).
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is human-made, it may be considered
harassment when disrupting or altering critical behaviors. It is
important to distinguish TTS and PTS, which persist after the sound
exposure, from masking, which occurs during the sound exposure. Because
masking (without resulting in TS) is not associated with abnormal
physiological function, it is not considered a physiological effect,
but rather a potential behavioral effect (though not necessarily one
that would be associated with harassment).
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al., 2000;
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2010; Holt
et al., 2009). Masking can be reduced in situations where the signal
and noise come from different directions (Richardson et al., 1995),
through amplitude modulation of the signal, or through other
compensatory behaviors (Hotchkin and Parks, 2013). Masking can be
tested directly in captive species (e.g., Erbe, 2008), but in wild
populations it must be either modeled or inferred from evidence of
masking compensation. There are few studies addressing real-world
masking sounds likely to be experienced by marine mammals in the wild
(e.g., Branstetter et al., 2013).
Marine mammals at or near the proposed CBY project site may be
exposed to anthropogenic noise which may be a source of masking.
Vocalization changes may result from a need to compete with an increase
in background noise and include increasing the source level, modifying
the frequency, increasing the call repetition rate of vocalizations, or
ceasing to vocalize in the presence of increased noise (Hotchkin and
Parks, 2013). For example, in response to loud noise, beluga whales may
shift the frequency of their echolocation clicks to prevent masking by
anthropogenic noise (Tyack, 2000; Eickmeier and Vallarta, 2022).
Masking occurs in the frequency band or bands that animals utilize
and is more likely to occur in the presence of broadband, relatively
continuous noise sources such as vibratory pile driving. Energy
distribution of pile driving covers a broad frequency spectrum, and
sound from pile driving would be within the audible range of pinnipeds
and cetaceans present in the proposed action area. While some
construction during the CBY's activities may mask some acoustic signals
that are relevant to the daily behavior of marine mammals, the short-
term duration and limited areas affected make it very unlikely that the
fitness of individual marine mammals would be impacted.
Airborne Acoustic Effects--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving
or DTH that have the potential to cause behavioral harassment,
depending on their distance from the activities. Cetaceans are not
expected to be exposed to airborne sounds that would result in
harassment as defined under the MMPA.
Airborne noise would primarily be an issue for pinnipeds that are
swimming or hauled out near the project site within the range of noise
levels elevated above the airborne acoustic harassment criteria. We
recognize that pinnipeds in the water could be exposed to airborne
sound that may result in behavioral harassment when swimming with their
heads above water. Most likely, airborne sound would cause behavioral
responses similar to those discussed above in relation to underwater
sound. For instance, anthropogenic sound could cause hauled-out
pinnipeds to exhibit changes in their normal behavior, such as
reduction in vocalizations, or cause them to temporarily abandon the
area and move further from the source. However, these animals would
previously have been `taken' because of exposure to underwater sound
above the behavioral

[[Page 46823]]

harassment thresholds, which are in all cases larger than those
associated with airborne sound. Thus, the behavioral harassment of
these animals is already accounted for in these estimates of potential
take. Therefore, we do not believe that authorization of incidental
take resulting from airborne sound for pinnipeds is warranted, and
airborne sound is not discussed further.

Marine Mammal Habitat Effects

Construction activities at the Yakutat Small Boat Harbor
Replacement Project could have localized, temporary impacts on marine
mammal habitat and their prey by increasing in-water SPLs and slightly
decreasing water quality. Increased noise levels may affect acoustic
habitat (see Auditory Masking discussion above) and adversely affect
marine mammal prey in the vicinity of the project area (see discussion
below). During in-water vibratory and impact pile driving and DTH,
elevated levels of underwater noise would ensonify a portion of
Shipyard Cove, Yakutat Roads, Deep Bay and Sea Otter Bay where both
fish and some mammals occur and could affect foraging success.
Additionally, marine mammals may avoid the area during construction;
however, displacement due to noise is expected to be temporary and is
not expected to result in long-term effects to the individuals or
populations.
Water Quality--Temporary and localized reduction in water quality
would occur as a result of in-water construction activities. Most of
this effect would occur during the installation and removal of piles
when bottom sediments are disturbed. The installation and removal of
piles would disturb bottom sediments and may cause a temporary increase
in suspended sediment in the project area. During pile removal,
sediment attached to the pile moves vertically through the water column
until gravitational forces cause it to slough off under its own weight.
The small resulting sediment plume is expected to settle out of the
water column within a few hours. Studies of the effects of turbid water
on fish (marine mammal prey) suggest that concentrations of suspended
sediment can reach thousands of milligrams per liter before an acute
toxic reaction is expected (Burton, 1993).
Effects to turbidity and sedimentation are expected to be short-
term, minor, and localized. Suspended sediments in the water column
should dissipate and quickly return to background levels in all
construction scenarios. Turbidity within the water column has the
potential to reduce the level of oxygen in the water and irritate the
gills of prey fish species in the proposed project area. However,
turbidity plumes associated with the project would be temporary and
localized, and fish in the proposed project area would be able to move
away from and avoid the areas where plumes may occur. Therefore, it is
expected that the impacts on prey fish species from turbidity, and
therefore on marine mammals, would be minimal and temporary. In
general, the area likely impacted by the proposed construction
activities is relatively small compared to the available marine mammal
habitat in the Gulf of Alaska, and does not include any areas of
particular importance.
In-Water Construction Effects on Potential Prey--Sound may affect
marine mammals through impacts on the abundance, behavior, or
distribution of prey species (e.g., crustaceans, cephalopods, fish,
zooplankton). Marine mammal prey varies by species, season, and
location and, for some, is not well documented. Here, we describe
studies regarding the effects of noise on known marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009).
Depending on their hearing anatomy and peripheral sensory structures,
which vary among species, fishes hear sounds using pressure and
particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds which are especially strong and/or
intermittent low-frequency sounds, and behavioral responses such as
flight or avoidance are the most likely effects. Short duration, sharp
sounds can cause overt or subtle changes in fish behavior and local
distribution. The reaction of fish to noise depends on the
physiological state of the fish, past exposures, motivation (e.g.,
feeding, spawning, migration), and other environmental factors.
Hastings and Popper (2005) identified several studies that suggest fish
may relocate to avoid certain areas of sound energy. Additional studies
have documented effects of pile driving on fish, although several are
based on studies in support of large, multiyear bridge construction
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings,
2009). Several studies have demonstrated that impulse sounds might
affect the distribution and behavior of some fishes, potentially
impacting foraging opportunities or increasing energetic costs (e.g.,
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al.,
1992; Santulli et al., 1999; Paxton et al., 2017). However, some
studies have shown no or slight reaction to impulse sounds (e.g., Pena
et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott
et al., 2012). More commonly, though, the impacts of noise on fish are
temporary.
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function likely is
restored when damaged cells are replaced with new cells. Halvorsen et
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours
for one species. Impacts would be most severe when the individual fish
is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012b; Casper et al., 2013).
The greatest potential impact to fishes during construction would
occur during unattenuated impact pile and DTH. In-water construction
activities would only occur during daylight hours, allowing fish to
forage and transit the project area in the evening. Vibratory pile
driving would possibly elicit behavioral reactions from fishes such as
temporary avoidance of the area but is unlikely to cause injuries to
fishes or have persistent effects on local fish populations.
Construction also would have minimal permanent and temporary
impacts on benthic invertebrate species, a marine mammal prey source.
In addition, it should be noted that the area in question is low-
quality habitat since it is already highly developed and experiences a
high level of anthropogenic noise from normal operations and other
vessel traffic. In general, any negative impacts on marine mammal prey
species are expected to be minor and temporary.
Fish populations in the proposed project area that serve as marine
mammal prey could be temporarily affected by noise from pile
installation and removal. The frequency range in

[[Page 46824]]

which fishes generally perceive underwater sounds is 50 to 2,000 Hz,
with peak sensitivities below 800 Hz (Popper and Hastings, 2009). Fish
behavior or distribution may change, especially with strong and/or
intermittent sounds that could harm fishes. High underwater SPLs have
been documented to alter behavior, cause hearing loss, and injure or
kill individual fish by causing serious internal injury (Hastings and
Popper, 2005).
The most likely impact to fish from pile driving activities in the
project area would be temporary behavioral avoidance of the area. The
duration of fish avoidance of an area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution and
behavior is anticipated. In general, impacts to marine mammal prey
species are expected to be minor and temporary due to the expected
short daily duration of individual pile driving events.
In-Water Construction Effects on Potential Foraging Habitat--The
area likely impacted by the project, Shipyard Cove across the Strait to
Deep Bay and Sea Otter Bay, is relatively small compared to the
available habitat in Yakutat Bay and the larger Gulf of Alaska. The
total area affected by pile installation and removal and the new
footprint is small compared to the vast foraging area available to
marine mammals in the area. Pile driving and removal at the project
site would not obstruct long-term movements or migration of marine
mammals.
Avoidance by potential prey (i.e., fish) of the immediate area due
to the temporary loss of this foraging habitat is also possible. The
duration of fish and marine mammal avoidance of this area after pile
driving stops is unknown, but a rapid return to normal recruitment,
distribution, and behavior is anticipated. Any behavioral avoidance by
fish or marine mammals of the disturbed area would still leave
significantly large areas of fish and marine mammal foraging habitat in
the nearby vicinity.
In summary, given the short daily duration of sound associated with
individual pile driving events and the relatively small areas being
affected, pile driving activities associated with the proposed action
are not likely to have a permanent adverse effect on any fish habitat,
or populations of fish species. Any behavioral avoidance by fish of the
disturbed area would still leave significantly large areas of fish and
marine mammal foraging habitat in the nearby vicinity. Thus, we
conclude that impacts of the specified activity are not likely to have
more than short-term adverse effects on any prey habitat or populations
of prey species. Further, any impacts to marine mammal habitat are not
expected to result in significant or long-term consequences for
individual marine mammals, or to contribute to adverse impacts on their
populations.

Estimated Take of Marine Mammals

This section provides an estimate of the number of incidental takes
proposed for authorization through the IHA, which will inform NMFS'
consideration of ``small numbers,'' the negligible impact
determinations, and impacts on subsistence uses.
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 use
of pile driving and DTH has the potential to result in disruption of
behavioral patterns for individual marine mammals. There is also some
potential for auditory injury (AUD INJ) (Level A harassment) to result,
primarily for very high frequency species and/or phocids because
predicted AUD INJ zones are larger than for high-frequency species and/
or otariids. The proposed 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 proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic criteria above which NMFS believes there is
some reasonable potential for marine mammals to be behaviorally
harassed or incur some degree of AUD INJ; (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 proposed
take estimates.

Acoustic Criteria

NMFS recommends the use of acoustic criteria 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 AUD INJ of some degree (equated to
Level A harassment). We note that the criteria for AUD INJ, as well as
the names of two hearing groups, have been recently updated (NMFS,
2024) as reflected below in the Level A harassment section.
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; Southall et al., 2021; Ellison et
al., 2012). Based on what the available science indicates and the
practical need to use a threshold based on a metric that is both
predictable and measurable for most activities, NMFS typically uses a
generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS generally predicts that marine
mammals are likely to be behaviorally harassed in a manner considered
to be Level B harassment when exposed to underwater anthropogenic noise
above root-mean-squared pressure received levels (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, estimates of take
by Level B harassment based on these behavioral harassment thresholds
are expected to include any likely takes by 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

[[Page 46825]]

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.
CBY's proposed activity includes the use of continuous (vibratory
pile driving and DTH) and impulsive (DTH 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' Updated Technical Guidance for Assessing
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version
3.0) (Updated Technical Guidance, 2024) identifies dual criteria to
assess AUD INJ (Level A harassment) to five different underwater marine
mammal groups (based on hearing sensitivity) as a result of exposure to
noise from two different types of sources (impulsive or non-impulsive).
CBY's proposed activity includes the use of impulsive (DTH and impact
pile driving) and non-impulsive (vibratory pile driving and DTH)
sources.
The 2024 Updated Technical Guidance criteria include both updated
thresholds and updated weighting functions for each hearing group. The
thresholds are provided in table 4 below. The references, analysis, and
methodology used in the development of the criteria are described in
NMFS' 2024 Updated Technical Guidance, which may be accessed at:
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools</a>.

Table 4--Thresholds Identifying the Onset of Auditory Injury
----------------------------------------------------------------------------------------------------------------
AUD INJ onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 222 dB; Cell 2: LE,LF,24h: 197 dB.
LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans.......... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,HF,24h: 201 dB.
LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans.... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,VHF,24h: 181 dB.
LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 223 dB; Cell 8: LE,PW,24h: 195 dB.
LE,PW,24h: 183 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 230 dB; Cell 10: LE,OW,24h: 199 dB.
LE,OW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric criteria for impulsive sounds: Use whichever criteria results in the larger isopleth for
calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure
level criteria associated with impulsive sounds, the PK SPL criteria are recommended for consideration for non-
impulsive sources.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
exposure level (LE,p) has a reference value of 1 [mu]Pa\2\s. In this table, criteria are abbreviated to be
more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
hearing range of marine mammals underwater (i.e., 7 Hz to 165 kHz). The subscript associated with cumulative
sound exposure level criteria indicates the designated marine mammal auditory weighting function (LF, HF, and
VHF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The weighted
cumulative sound exposure level criteria 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 criteria 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 proposed project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., pile driving and removal, and
DTH).
The project includes vibratory pile installation and removal,
impact pile driving, and DTH. Source levels for these activities are
based on reviews of measurements of the same or similar types and
dimensions of piles available in the literature. Source levels for each
pile size are presented in table 5. Source levels for vibratory
installation and removal of piles of the same diameter are assumed to
be the same.

Table 5--Estimates of Mean Underwater Sound Levels Generated During In-Water Vibratory and Impact Pile
Installation and Vibratory Pile Removal
----------------------------------------------------------------------------------------------------------------
Proxy sound source levels at 10m (dB
re 1 [mu]Pa)
----------------------------------------
Source Source type RMS source Sound Peak source Reference
level (SPL exposure level (SPL
RMS) level (SEL) RMS)
----------------------------------------------------------------------------------------------------------------
Existing steel piles (16'' steel Non-impulsive, 160 153.0 181.0 Sexton, 2007.
pipe). continuous
removal.
Existing timber piles (12'' Non-impulsive, 162.0 153.0 199.0 Caltrans 2020.
timber). continuous
removal.
Trestle template piles (24'' Non-impulsive, 163.0 153.0 181.0 Naval Base Kitsap
steel pipe or equivalent). continuous Bangor Test Pile
installation & (Navy (2012) and
removal. EHW-2 (Navy).
Trestle piles (12.75'' steel Non-impulsive, 160.0 155.0 171.0 Sexton, 2007.
pipe). continuous
installation.
Impulsive 177.0 167.0 192.0 Caltrans 2015,
installation. 2020.
Float piles (24'' steel pipe)... Non-impulsive, 163.0 153.0 181.0 Sexton, 2007.
continuous
installation.

[[Page 46826]]

Impulsive 190 177 203 Caltrans 2015.
Installation.
DTH Drilling...... 167.0 159.0 184.0 Heyvaert & Reyff
2021.
----------------------------------------------------------------------------------------------------------------
Note: peak = peak sound level; rms = root mean square; SEL = sound exposure level.
\1\ Sources: Anacortes, WA (Sexton, 2007).
\2\ Sources: Naval Base Kitsap Bangor Test Pile (Navy (2012) and EHW-2 (Navy 2013) Gustavus (Miner, 2020).

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 x Log10 (R1/R2),

Where:

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

Absent site-specific acoustical monitoring with differing measured
TL, a practical spreading value of 15 is used as the TL coefficient in
the above formula. Site-specific TL data for Shipyard Cove where the
YSBH is located are not available; therefore, the default coefficient
of 15 is used to determine the distances to the Level A harassment and
Level B harassment thresholds.
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional User
Spreadsheet tool to accompany the 2024 Updated 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 driving, the optional User Spreadsheet
tool predicts the distance at which, if a marine mammal remained at
that distance for the duration of the activity, it would be expected to
incur auditory injury. Inputs used in the User Spreadsheet (e.g.,
number of piles per day, duration and/or strikes per pile) are found in
tables 1, 5 and 6. The resulting estimated isopleths are reported below
(table 6).

Table 6--Predicted Level A and Level B Harassment Isopleths
--------------------------------------------------------------------------------------------------------------------------------------------------------
AUD INJ Isopleths(m)/area (km\2\)
------------------------------------------------------------ Disturbance
Max Min./ (VHF) Very Isopleth
Source Source type piles (Strikes) (LF) Low (HF) High high Phocid Otariid (m)/area
per day per pile frequency frequency frequency pinnipeds pinnipeds (km\2\)
cetaceans cetaceans cetaceans (PW) (OW)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
Existing steel piles (16'' steel Non-impulsive, 15 15 30.3 11.6 24.7 39 13.1 7,356.4
pipe). continuous removal. 0.0437 0.0345 0.0312 0.0436 0.0354 4.4207
Existing timber piles (12'' timber) Non-impulsive, 15 15 26.0 10.0 21.2 33.4 11.2 6,309.6
continuous removal. 0.0396 0.0312 0.0396 0.0436 0.0354 4.4207
--------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Trestle template piles (24'' steel Non-impulsive, 4 20 15.2 5.8 12.4 19.5 6.6 7,356.4
pipe or equivalent). continuous 0.0354 0.0312 0.0396 0.0354 0.0312 4.4207
installation &
removal.
--------------------------------------------------------------------------------------------------------------------------------------------------------
New Pile Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Trestle piles (12.75'' steel pipe). Non-impulsive, 4 20 9.6 3.7 7.8 12.3 4.2 4,641.6
continuous 0.0312 0.0312 0.0312 0.0354 0.0312 4.4207
installation.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impulsive 4 500 135.5 17.3 209.6 120.3 44.9 135.9
installation. 0.1019 0.0354 0.1495 0.0968 0.0464 0.1019
Float piles (24'' steel pipe)...... Non-impulsive, 5 20 17.6 6.8 14.4 22.7 7.6 7,356.4
continuous 0.0354 0.0312 0.034 0.0396 0.0312 4.4207
installation.
Impulsive 5 1000 1,158.3 147.8 1,792.4 1,028.9 383.5 1,000
Installation. 1.1225 0.1100 2.663 0.991 0.2436 0.9446
DTH Drilling......... 2 180 899.8 114.8 1,392.4 799.3 297.9 13,593.6
0.7918 0.0917 1.7076 0.6571 0.19388 \1\ 4.4207
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Even though the isopleth is larger than other isopleths, the associated area is equivalent to areas of several other isopleths due clipping of the
ensonified area by landforms.

[[Page 46827]]

Marine Mammal Occurrence and Take Estimate

In this section we provide information about the occurrence of
marine mammals, including density or other relevant information which
will inform the take calculations.
CBY calculated occurrence estimates based on literature and
communication with locals in the Yakutat area, notably a local charter
boat operator. They then multiplied that occurrence by estimated days,
weeks, or months of work. After reviewing their occurrence estimates,
NMFS believed some of the estimates to be inconsistent with the cited
literature and local observations. Following careful review of the
analysis and literature presented by CBY in its application, including
marine mammal occurrence data and estimates, NMFS has preliminarily
determined that the occurrence estimates for some species represent the
best available scientific information for marine mammal abundance in
the action area. The following paragraphs explain how the local
abundance of authorized species was determined (table 7). Table 8
depicts the proposed take by stock, harassment type, and as a
percentage of stock abundance.

Humpback Whale

Dalheim et al. (2019) reported an avg group size between 1.2-2 of
humpback whales while the Yakutat Charter Boat Company reports group
sizes ranging up to 10 individuals, but typically an average of three
whales per group. It was assumed that there would be 3 whales/group
with one group sighting per day over 54 days. Approximately 97.6
percent likely originate from the Hawai[revaps]i stock while 2.4
percent are from the Mexico DPS (Wade 2021). No take by Level A
harassment is expected due to the large shutdown zone and easy
observability of animals from this species.

Gray Whale

The local boat charter company reports gray whales are occasionally
seen travelling in groups of three. It was assumed that there would be
one whale spotted very three days. No take by Level A is expected due
to the large shutdown zone and easy observability of animals from this
species.

Killer Whale

Killer whale group sizes in Southeast Alaska vary by ecotype and by
season (Dalheim et al. 2009). Resident killer whales had group sizes of
15.6-70 in the spring, 25-45 in the summer, and 15-36 in the fall; and
transient killer whales had group sizes of 1-14-5.6 in the spring,
4.25-14.5 in the summer, and 1-16.33 in the fall. The local charter
boat reports the whales are intermittently spotted about once a month,
traveling in groups of up to 10 individuals. Therefore, it is assumed
that there will be a single group of 10 animals spotted once per month.
For the purposes of estimating the percentage of each stock taken, it
is assumed that all takes would accrue to each stock.
No take by Level A harassment is proposed due to the small AUD INJ
zone and high visibility of this species.

Harbor Porpoise

An average group size of two has been reported by Zerbini et al.
(2022) while NMFS has indicated that group sizes can be as large as 10
(NMFS 2025). Dalheim et al. (2009) reported a mean group size of 1.2-
2.7. For estimated proposed take it was assumed that there would be
three animals per group with a single group observed per day for 54
days of in-water driving. Take by Level A harassment is proposed since
the Level A harassment zone is larger than the Level B harassment zone
during impact driving and DTH. The apportioning of Level A and Level B
harassment takes is described below.

Beluga Whale

Observation of beluga whales in the project is uncommon. This is
not surprising given the small number of animals (<20) in this small
resident population and relatively large habitat area. Lucey et al.
(2015) reported two sightings of beluga whales in Yakutat Bay off
Khantaak Island, within approximately 5 miles of the project site. The
sightings occurred in March 2003 and June 2008. Lucey et al. (2015)
also compiled 76 beluga sightings from 1938 to 2013 within Yakutat Bay.
The average group size was reported to be 6 to 10 individuals per
sighting. Sightings of belugas from 1976 to 2000 in the Yakutat area
from various sources were compiled in Laidre et al (2000). Sightings in
the 1990s tended to be groups of 1 to 11 individuals. The core habitat
area for this small resident population is Disenchantment Bay,
approximately 50 km to the northwest. Given the rarity of this group,
NMFS considers it reasonably likely that groups of up to 10 belugas may
occur within the project area up to two times over the course of the
project. No take by Level A harassment is proposed due to the small AUD
INJ zone.

Steller Sea Lion

A marine mammal monitoring report from the Ocean Cape Seafoods Dock
Fender Repairs project in Monti Bay reported a single occurrence of an
unidentified otariid, presumably a Steller sea lion, during 1 week in
October 2016 (Bacon et al. 2016). The local boat charter reported a
single animal camped out at the YSBH harbor, but no other information
about regular occurrences was available. Steller sea lions are also
known to congregate around fishing boats in harbors and marinas. Since
the YSBH houses a number of commercial fishing vessels, it was
conservatively assumed that six animals could be observed per day over
54 days of in-water work. No take by Level A harassment is proposed due
to the small AUD INJ zone.

California Sea Lion

California sea lion sightings in Southeast and Southcentral Alaska
are relatively rare but do occur on occasion (Woodford 2020). There are
no records of California sea lions in the GBIFn the project area (GBIF
2024). A marine mammal monitoring report from the Ocean Cape Seafoods
Dock Fender Repairs project in Monti Bay reported one occurrence of a
single unidentified otariid during 1 week in Oct 2016 (Bacon et al.
2016). CBY conservatively proposed, and NMFS concurs, that there could
be a single sighting per week over the 24-week project timeline. No
take by Level A harassment is proposed due to the small AUD INJ zone.

Northern Fur Seal

Norther fur seals are uncommon in the project area as there are no
definitive observations on record. A marine mammal monitoring report
from the Ocean Cape Seafoods Dock Fender Repairs project in Monti Bay
reported one occurrence of a single unidentified otariid, which may
have been a fur seal, during one week in October 2016 (Bacon et al.
2016). CBY conservatively proposed, and NMFS concurs that a single
animal could be observed during each month of the proposed project. No
take by Level A harassment is proposed due to the small AUD INJ zone.

Harbor Seal

The local charter boat reports that harbor seals not typically
observed entering Shipyard Cove but are regularly recorded in Yakutat
Bay and associated fjords of Disenchantment Bay, where they use glacial
ice for critical life stages like pupping and molting. Records of
harbor seals in the GBIF show 30 occurrences reported by the public and
agencies within and immediately offshore of Yakutat Bay in the past 20
years (GBIF 2024). It is conservatively assumed that three harbor seals
would be observed per day over 54 in-water

[[Page 46828]]

work days. Take by Level A harassment is proposed for authorization
because the Level A harassment zone is larger than the Level B
harassment zone for impact driving and DTH activities. The apportioning
of Level A and Level B harassment takes is described below.
Total exposure estimates were calculated by multiplying the number
of days of work (54 days total; 22 days of vibratory-only activities,
and 32 days of vibratory, impact, and DTH activities) by the occurrence
estimates for each species, and total exposures were then divided into
estimates of take by Level A and Level B harassment. For days with
impact and DTH activities, there is potential for take by Level A
harassment for very high-frequency cetaceans (harbor porpoises) and
phocid pinnipeds (harbor seals) due to the larger Level A harassment
zones associated with animals in these hearing groups. In some
instances, the largest zones for some species are greater than the
shutdown zones due to the cryptic nature and assumed lower
detectability of some species and the sensitivity of these species'
hearing thresholds. CBY calculated estimated take by Level A harassment
for these species by calculating the ratio of the area of the Level A
harassment zones to the area of the maximum Level B harassment zone.
This ratio was multiplied by the exposure estimate for days with impact
driving and DTH activities to get the estimated take by Level A
harassment. Take by Level B harassment was then calculated by
subtracting the calculated take by Level A harassment from the total
exposure estimate. This was only necessary for harbor porpoises and
harbor seals as they are the only species for which the Level A
harassment zones exceeded the Level B harassment zone. Calculations are
presented below.
Harbor Porpoise
3 animals/day x 22 days vibratory driving = 66 exposures

3 animals/day x 32 days vibratory/impact/DTH = 96 exposures

Ratio of Maximum Level A harassment area (2.663)/Maximum Level B
harassment area (4.4207) = 0.60

Level A harassment estimate = 0.60 * 96 animals = 58 takes by Level A
harassment

Level B harassment estimate = 66 + 96 - 58 = 104 takes by Level B
harassment
Harbor Seal

3 animals/day x 22 days vibratory driving = 66 exposures

3 animals/day x 32 days vibratory/impact/DTH = 96 exposures

Ratio of Maximum Level A harassment area (0.991)/Maximum Level B
harassment area (4.4207) = 0.22

Level A harassment estimate = 0.22 * 96 animals = 22 takes by Level A
harassment

Level B harassment estimate = 66 + 96 - 22 = 140 takes by Level B
harassment

Table 7--Species Occurrence and Total Exposure Estimates
------------------------------------------------------------------------
Species Abundance estimate
------------------------------------------------------------------------
Humpback whale............... 3 whales/group x 1 group/day x 54 days
=162 spilt between 2 stocks.
Gray whale................... 1 whale every 3 days =18.
Killer whale................. 10 whales/group x 1 group/every month (7)
= 70 split between 3 stocks.
Harbor porpoise.............. 3/group x 1 group/day x 54 days in-water
driving = 162 animals split between
Level A and Level B harassment takes.
Beluga whale................. 10/group x 2 groups over project duration
= 20.
Steller Sea lion............. 6/day x 54 days vibratory = 324.
California sea lion.......... 1/week x 24 weeks = 24.
Northern fur seal............ 1 animal/month x 7 months = 7.
Harbor seal.................. 3/day x 54 days = 162 animals split
between Level A and Level B harassment
takes.
------------------------------------------------------------------------

Table 8--Proposed Take by Stock, Harassment Type, and as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
Level A Level B
Species Stock Stock abundance harassment harassment Percentage
take take
----------------------------------------------------------------------------------------------------------------
Humpback whale.................. Hawai[revaps]i..... 11,278............ 0 158 1.4
Mex-North \1\ N/A (918)......... 0 4 0.4
Pacific/Mexico DPS.
Gray whales..................... E. North Pacific... 29,260............ 0 18 0.06
Killer whales................... ENP Alaska Resident 1,920............. 0 70 3.6
ENP Gulf of Alaska, 302............... 0 23.1
Aleutian Islands,
and Bering Sea
Transient.
West Coast 349............... 0 20.0
Transient.
Harbor porpoises................ Yakutat/Southeast UNK............... 58 94 1.5
Alaska Offshore (11,146)..........
Waters stock).
Beluga whales................... Cook Inlet stock... 331............... 0 20 6.04
Steller sea lions............... Eastern DPS........ 36,308............ 0 297 0.8
Western DPS \2\.... 49,837............ 0 27 0.05
California sea lions............ U.S. stock......... 257,606........... 0 24 <0.01
Northern fur seals.............. Eastern Pacific.... 62,6618........... 0 7 <0.01
Harbor seals.................... Prince William 44,756............ 22 140 0.4
Sound.
----------------------------------------------------------------------------------------------------------------
\1\ For MMPA take apportionment and ESA section 7 consultation purposes, 2.4 percent are designated to the
Mexico-North Pacific stock, and the remaining are designated to the Hawai[revaps]i stock (Wade 2021).
\2\ Approximately 8.2 percent of SSLs in this area are from the WDPS (NMFS 2020).

[[Page 46829]]

Proposed 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.
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.
The mitigation requirements described below were proposed by CBY in
its adequate and complete application or are the result of subsequent
coordination between NMFS and CBY. CBY has agreed that all of the
mitigation measures are practicable. NMFS has fully reviewed the
specified activities and the mitigation measures to determine if the
mitigation measures would result in the least practicable adverse
impact on marine mammals and their habitat, as required by the MMPA,
and has determined the proposed measures are appropriate. NMFS
describes these below as proposed mitigation requirements and has
included them in the proposed IHA.
CBY must ensure that construction supervisors and crews, the
monitoring team, and relevant CBY staff are trained prior to the start
of all pile driving and DTH 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.

Pre- and Post-Activity Monitoring

<bullet> Monitoring must take place from 30 minutes prior to
initiation of pile driving and DTH activity (i.e., pre-clearance
monitoring) through 30 minutes post-completion of pile driving and DTH
activity; and,
<bullet> Pre-start clearance monitoring must be conducted during
periods of visibility sufficient for the lead protected species
observer (PSO) to determine that the shutdown zones indicated in table
10 are clear of marine mammals. Pile driving and DTH may commence
following 30 minutes of observation when the determination is made that
the shutdown zones are clear of marine mammals.

Soft Start

CBY 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.

Shutdown Zones

CBY would establish shutdown zones for all pile driving 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).
If a marine mammal is observed entering or within the shutdown
zones indicated in table 9, pile driving and DTH must be delayed or
halted. For in-water heavy machinery activities other than pile
driving, if a marine mammal comes within 10-m, work must stop and
vessels must reduce speed to the minimum level required to maintain
steerage and safe working conditions. A 10-m shutdown zone would also
serve 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 9, 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 would be monitored to the extent possible based
on PSO locations. If a marine mammal enters the Level B harassment
zone, in-water activities would continue and the animal's presence
within the estimated harassment zone would be documented.
CBY 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. If a
marine mammal species for which take is not authorized by this IHA
enters the shutdown zone, all in-water activities would cease until the
animal leaves the zone or has not been observed for at least 15
minutes. Pile driving would 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 CBY or its designated officials, the
in-water activity would be allowed to continue until the safety concern
has been addressed, and the animal would be continuously monitored.

[[Page 46830]]

Table 9--Shutdown Zones and Level B Harassment Zones
----------------------------------------------------------------------------------------------------------------
Shutdown zones--authorized species (m) Monitoring
-------------------------------------------------- zone (m)
Pile size/type Construction ------------
method LF HF VHF PW OW Level B
harassment
----------------------------------------------------------------------------------------------------------------
Pile Removal
----------------------------------------------------------------------------------------------------------------
Existing steel piles (16'' Non-impulsive, 40 40 40 40 40 7,360
round steel). continuous
removal.
Existing timber piles (12'' Non-impulsive, 30 10 30 40 20 6,310
timber). continuous
removal.
----------------------------------------------------------------------------------------------------------------
Temporary Piles
----------------------------------------------------------------------------------------------------------------
Template piles (24'' steel Non-impulsive, 20 10 20 20 10 7,360
pipe or equivalent). continuous
installation &
removal.
----------------------------------------------------------------------------------------------------------------
New Pile Installation
----------------------------------------------------------------------------------------------------------------
Trestle piles (12.75'' steel Non-impulsive, 10 10 10 20 10 4,650
pipe). continuous
installation.
Impulsive 140 20 210 130 50 140
installation.
Float piles (24'' steel pipe). Non-impulsive, 20 10 20 30 10 7,360
continuous
installation.
Impulsive 1,160 150 200 200 400 1,000
installation.
DTH Drilling..... 900 120 200 200 300 \1\ 13,600
----------------------------------------------------------------------------------------------------------------
\1\ This isopleth is considerably larger than other isopleths but is clipped by landforms.

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 lead PSO is
confident marine mammals within the shutdown zone could be detected.
CBY must employ PSOs and establish monitoring locations as
described in the marine mammal monitoring plan and the IHA. PSOs would
monitor the full shutdown zones 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.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed 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.

Proposed Monitoring and Reporting

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

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 and DTH activities must be conducted by PSOs meeting the
following requirements:

[[Page 46831]]

<bullet> PSOs must be independent of the activity contractor (for
example, employed by a subcontractor) and have no other assigned tasks
during monitoring periods;
<bullet> At least one PSO must have prior experience performing the
duties of a PSO during construction activity pursuant to a NMFS-issued
incidental take authorization;
<bullet> Other PSOs may substitute relevant experience (including
Alaska Native traditional knowledge), education (degree in biological
science or related field), or training for prior experience performing
the duties of a PSO during construction activity pursuant to a NMFS-
issued incidental take authorization or Letter of Concurrence (LOC);
and,
<bullet> 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 performing the
duties of a PSO during construction activities pursuant to a NMFS-
issued incidental take authorization.
<bullet> PSOs must be approved by NMFS prior to beginning any
activities subject to this IHA.
PSOs must have the following additional qualifications:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including the identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates, times and reason for implementation
of mitigation (or why mitigation was not implemented when required);
and marine mammal behavior; and,
<bullet> Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
CBY must assign a minimum of two PSOs to monitor during pile
driving and DTH. They must be stationed where they have an unobstructed
view of the work being conducted and unobstructed view of all the water
within the Shutdown Zones and as much of the Level B harassment zone as
possible. Optimal observation locations will be selected based on
visibility and the type of work occurring. 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.
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.
CBY shall conduct briefings between construction supervisors and
crews, PSOs, and CBY staff prior to the start of all pile driving
activities and when new personnel join the work. These briefings must
explain responsibilities, communication procedures, marine mammal
monitoring protocol, and operational procedures.

Reporting

A draft marine mammal monitoring report would be submitted to NMFS
within 90 days after the completion of pile driving and removal
activities, 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 would include an overall description of work completed, a
narrative regarding marine mammal sightings, and associated electronic
PSO data sheets. Specifically, the report must include:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> Construction activities occurring during each daily
observation period, including the number and type of piles driven or
removed and by what method (i.e., impact) and the total equipment
duration for vibratory removal for each pile or total number of strikes
for each pile (impact driving);
<bullet> PSO locations during marine mammal monitoring;
<bullet> Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance;
<bullet> Upon observation of a marine mammal, the following
information: (1) Name of PSO who sighted the animal(s) and PSO location
and activity at the time of sighting; (2) Time of sighting; (3)
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; (4)
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); (5) Estimated number of animals (min/max/best
estimate); (6) Estimated number of animals by cohort (adults,
juveniles, neonates, group composition, sex class, etc.); (7) Animal's
closest point of approach and estimated time spent within the
harassment zone; (8) Description of any marine mammal behavioral
observations (e.g., observed behaviors such as feeding or traveling),
including an assessment of behavioral responses thought to have
resulted from the activity (e.g., no response or changes in behavioral
state such as ceasing feeding, changing direction, flushing, or
breaching);
<bullet> Number of marine mammals detected within the harassment
zones and shutdown zones; by species; and,
<bullet> 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
final report would constitute the final report. If comments are
received, a final report addressing NMFS comments must be submitted
within 30 days after receipt of comments.

Reporting Injured or Dead Marine Mammals

In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, CBY must immediately cease
the specified activities and report the incident to the Office of
Protected Resources (<a href="/cdn-cgi/l/email-protection#4b1b1965021f1b65062425223f243922252c192e3b24393f380b25242a2a652c243d"><span class="__cf_email__" data-cfemail="ffafadd1b6abafd1b29091968b908d969198ad9a8f908d8b8cbf91909e9ed1989089">[email&#160;protected]</span></a>), NMFS and to
the Alaska Regional Stranding Coordinator as soon as feasible. If the
death or injury was clearly caused by the specified activity, CBY 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. CBY must not resume their activities until notified by
NMFS. The report must include the following information:

[[Page 46832]]

<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and,
<bullet> 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 human-caused mortality, or ambient noise levels).
To avoid repetition, the discussion of our analysis applies to all
the species listed in table 2, 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.
Pile driving and DTH activities associated with the CBY project
have the potential to disturb or displace marine mammals. Specifically,
the project activities may result in take, in the form of Level A and
Level B harassment, from underwater and in-air sounds generated from
pile driving and removal. Potential takes could occur if individuals
are present in the ensonified zone when these activities are underway.
Takes by Level B harassment would be due to potential behavioral
disturbance and TTS. Takes by Level A harassment would be due to
auditory injury. No serious injury or mortality is expected, even in
the absence of required mitigation measures, given the nature of the
activities. The potential for harassment would be further minimized
through the construction method and the implementation of the planned
mitigation measures.
Take by Level A harassment is authorized for harbor porpoises and
harbor seals to account for the possibility that an animal could enter
a Level A harassment zone and remain within that zone for a duration
long enough to incur auditory injury before being observed by PSOs.
Given the relatively short duration expected to drive each pile and
breaks 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 an extended
period. This is highly unlikely given the mobile nature of marine
mammals in the area. Any take by Level A harassment is expected to
arise from, at most, a small degree of auditory injury, i.e., minor
degradation (likely only a few dB) of hearing capabilities within
regions of hearing that align most completely with the energy produced
by vibratory and impact pile driving (i.e., the low-frequency region
below 2 kHz). Severe hearing impairment or impairment within the ranges
of greatest hearing sensitivity are unlikely. Animals would need to be
exposed to higher levels and/or longer duration than are anticipated.
Due to the small degree anticipated, any auditory injury incurred would
not be expected to affect the reproductive success or survival of any
individual, much less result in adverse impacts on the species or
stock.
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.
Behavioral responses of marine mammals to pile driving and DTH in
the ensonified area 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 the proposed 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 and DTH would occur intermittently
and for only a portion of the project's duration, any harassment would
be temporary.
Any impacts on marine mammal prey that would occur during CBY's
proposed activity would have, at most, short-term effects on foraging
of individual marine mammals, and likely no effect on the populations
of marine mammals as a whole. Indirect effects on marine mammal prey
during the construction are expected to be minor, and these effects are
unlikely to cause substantial effects on marine mammals at the
individual level, with no expected effect on annual rates of
recruitment or survival.
For all species and stocks, take would occur within a limited,
confined space (i.e., in-water ensonified area adjacent to the project
site) of the stock's range. While pinniped species are most likely to
occur within the immediate project area, the nearest officially
documented haulouts are outside of the ensonified area and located some
distance from the project area. There are no Steller sea lion haulouts
in the project area. The closest haulouts are between 8 km (harbor
seal) and 48 km (Steller sea lion) km from the project area.
There is a migratory BIA for the gray whale that includes the
months of January, March, April, May, November and December. In-water
construction operations would occur during the March through May period
when whales are migrating; however, the project area is inside Yakutat
Bay, a relatively sheltered area with only one entrance and exit point,
and gray whales are not expected to spend significant time nearby.
There is also a Yakutat Bay Beluga whale Small and Resident Population
BIA that is active year-

[[Page 46833]]

round. The core area for this population, however, is Disenchantment
Bay located approximately 50 km from the project site. Movement of
whales near Yakutat would likely occur infrequently and the amount of
time spent in the project area is expected to be low.
In addition, it is unlikely that minor noise effects in a small,
localized area of habitat would have any effect on the reproduction or
survival of any individuals, much less the stocks' annual rates of
recruitment or survival. 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 preliminary determination that the impacts resulting from
this activity are not expected to adversely affect any of the species
or stocks through effects on annual rates of recruitment or survival:
<bullet> No serious injury or mortality is anticipated or proposed
for authorization;
<bullet> Take by Level A harassment (AUD INJ) is proposed for
authorization for two species due to associated large Level A
harassment zones but the amount of take would be limited and of a low
degree;
<bullet> For all species and stocks, Yakutat Bay is a small and
peripheral part of their range;
<bullet> The intensity of anticipated take by Level B harassment is
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 driving and DTH is occurring, with
some low-level TTS that may limit the detection of acoustic cues for
relatively brief periods;
<bullet> 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;
<bullet> The ensonified areas are small relative to the overall
habitat ranges of all species and stocks; and,
<bullet> The lack of anticipated significant or long-term negative
effects to marine mammal habitat.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.

Small Numbers

As noted previously, only take of small numbers of marine mammals
may be authorized under section 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 (86 FR 5322,
January 19, 2021). Additionally, other qualitative factors may be
considered in the analysis, such as the temporal or spatial scale of
the activities.
Another circumstance in which NMFS considers it appropriate to make
a small numbers finding is in the case of a species or stock that may
potentially be taken but is either rarely encountered or only expected
to be taken on rare occasions. In that circumstance, one or two assumed
encounters with a group of animals (meaning a group that is traveling
together or aggregated, and thus exposed to a stressor at the same
approximate time) should reasonably be considered small numbers,
regardless of consideration of the proportion of the stock (if known),
as rare encounters resulting in take of one or two groups should be
considered small relative to the range and distribution of any stock.
While the percentage of stock taken for the Cook Inlet beluga whale
stock is below one third, the Yakutat portion of the Cook Inlet beluga
whale stock is considered to be resident in the waters around Yakutat,
particularly in Disenchantment Bay, and consists of fewer than 20
individuals. It is possible that all or a subset of these whales will
visit the project site during the construction period during their
regular movements in the area. NMFS considers it reasonably likely that
Yakutat belugas may occur up to two times during the project. Based on
the rarity of encounters with this group expected, this represents
small numbers for this stock.
For all other stocks, except for the ENP Gulf of Alaska, Aleutian
Islands, and Bering Sea transient and West Coast transient stocks of
killer whale, the proposed number of takes is less than one-third of
the best available population abundance estimate (table 8). The numbers
of animals proposed for authorization to be taken from these stocks
would be considered small relative to the relevant stocks' abundances,
even if each estimated taking occurred to a new individual--an
extremely unlikely scenario. The estimated take of the two killer whale
stocks assumes that all takes would be accrued by a single stock. This
is highly unlikely for animals with extended habitat ranges throughout
coastal Alaska down to California.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals would be taken relative to the population
size of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

In order to issue an IHA, NMFS must find that the specified
activity will not have an ``unmitigable adverse impact'' on the
subsistence uses of the affected marine mammal species or stocks by
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50
CFR 216.103 as an impact resulting from the specified activity: (1)
That is likely to reduce the availability of the species to a level
insufficient for a harvest to meet 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.
Harbor seals and sea lions have traditionally been taken as part of
subsistence harvests in Yakutat. Because of the high hunting pressure
harbor seals may avoid areas like Monti Bay and Yakutat Roads where
they are easily visible and readily accessible to hunters, although
they are still expected to be common within the range of construction
impacts. The small boat harbor is the primary access point for
subsistence users to the traditional seal hunting grounds in
Disenchantment Bay

[[Page 46834]]

and some temporary disruptions to mooring availability during
construction would occur, but replacement of the harbor to provide safe
marine access into the future would be beneficial to subsistence users
in the long term.
The proposed 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. Some minor, short-term harassment of Steller sea
lions and harbor seals could occur, potentially including displacement
from Yakutat Bay and into the surrounding habitat. Displacement is
expected to be short-term and temporary, and limited to the immediate
project area. Therefore, any effects on subsistence harvest activities
in the project areas are expected to be minimal and would not have an
adverse impact on overall harvest.
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 proposed mitigation and
monitoring measures, NMFS has preliminarily determined that there will
not be an unmitigable adverse impact on subsistence uses from CBY's
proposed activities.

Endangered Species Act

Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.)
requires that each Federal agency ensures that any action it
authorizes, funds, or carries out is not likely to jeopardize the
continued existence of any endangered or threatened species or result
in the destruction or adverse modification of designated critical
habitat. To ensure ESA compliance for the issuance of incidental take
authorizations, NMFS consults internally whenever we propose to
authorize take for ESA-listed species, in this case with the NMFS
Office of Protected Resources Alaska Regional Office.
NMFS is proposing to authorize take of humpback whale (Mexico DPS;
Mex-North Pacific) and Steller sea lion (western DPS), which are listed
under the ESA.
The Permits and Conservation Division has requested initiation of
section 7 consultation with the Alaska Regional Office for the issuance
of this IHA. NMFS will conclude the ESA consultation prior to reaching
a determination regarding the proposed issuance of the authorization.

Proposed Authorization

As a result of these preliminary determinations, NMFS proposes to
issue an IHA to CBY for conducting construction activities in Yakutat,
Alaska, provided the previously mentioned mitigation, monitoring, and
reporting requirements are incorporated. A draft of the proposed IHA
can be found at: <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>.

Request for Public Comments

We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA for the proposed
construction. We also request comment on the potential renewal of this
proposed IHA as described in the paragraph below. Please include with
your comments any supporting data or literature citations to help
inform decisions on the request for this IHA or a subsequent renewal
IHA.
On a case-by-case basis, NMFS may issue a one-time, 1-year renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activity section of this notice is planned or (2) the activities as
described in the Description of Proposed Activity section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
<bullet> A request for renewal is received no later than 60 days
prior to the needed renewal IHA effective date (recognizing that the
renewal IHA expiration date cannot extend beyond 1 year from expiration
of the initial IHA).
<bullet> The request for renewal must include the following:
1. An explanation that the activities to be conducted under the
requested renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
2. A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
<bullet> Upon review of the request for renewal, the status of the
affected species or stocks, and any other pertinent information, NMFS
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.

Dated: September 25, 2025.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2025-19008 Filed 9-29-25; 8:45 am]
BILLING CODE 3510-22-P

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