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Notice2026-20789

Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the City and Borough of Juneau's Seawalk Extension Project, Juneau, Alaska

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Published

October 13, 2026

Issuing agencies

Commerce DepartmentNational Oceanic and Atmospheric Administration

Abstract

NMFS has received a request from the City and Borough of Juneau (CBJ) for authorization to take marine mammals incidental to the Seawalk Extension Project in Juneau, Alaska (AK). 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 91 Issue 196 (Tuesday, October 13, 2026)</title>
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[Federal Register Volume 91, Number 196 (Tuesday, October 13, 2026)]
[Notices]
[Pages 64890-64912]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-20789]

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XF854]

Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the City and Borough of Juneau's
Seawalk Extension Project, Juneau, 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 and Borough of
Juneau (CBJ) for authorization to take marine mammals incidental to the
Seawalk Extension Project in Juneau, Alaska (AK). 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

[[Page 64891]]

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 November
12, 2026.

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#6e273a3e40040f0d010c1b1d2e00010f0f40090118"><span class="__cf_email__" data-cfemail="5e170a0e70343f3d313c2b2d1e30313f3f70393128">[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/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>. In case of problems
accessing these documents, please call the contact listed below.
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: Kristy Jacobus, 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)(A) and (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). If such findings are made, NMFS must prescribe the
permissible methods of taking; other ``means of effecting the least
practicable adverse impact'' on the affected species or stocks and
their habitat, paying particular attention to rookeries, mating
grounds, and areas of similar significance, and on the availability of
the species or stocks for taking for certain subsistence uses (referred
to 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
(see also 16 U.S.C. 1362; 50 CFR 216.3, 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 March 3, 2026, NMFS received a request from CBJ for an IHA to
take marine mammals incidental to a seawalk extension project in
Juneau, AK. Following NMFS' review of the application, CBJ submitted
additional information on May 29, July 8, July 21, and August 3, 2026.
A revised application was submitted on September 10, 2026, which NMFS
deemed adequate and complete on September 14, 2026. CBJ's request is
for take of five species of marine mammals by Level B harassment, and
for a subset of two species, Level A harassment. Neither CBJ nor NMFS
expect serious injury or mortality to result from the proposed project
and, therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

CBJ proposes to extend the existing seawalk from the Franklin Dock
to the AJ Dock to provide safe and continuous pedestrian access between
cruise vessels moored at the AJ Dock and downtown Juneau. The project
includes removal of an existing dock and mooring dolphins and unused
timber piles; installation and removal of temporary template piles; and
installation of a new seawalk, cruise ship mooring dolphin, and an
access catwalk. Activities that have the potential to cause incidental
take by Level A harassment and Level B harassment of marine mammals
include vibratory pile driving (including installation and removal),
impact pile driving, and down-the hole (DTH) drilling. Herein, unless
otherwise specified, the term ``pile driving'' refers to impact pile
installation and vibratory installation and removal.

Dates and Duration

The proposed IHA would be valid for the statutory maximum of 1 year
from the date of effectiveness. It will 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. The specified activities are currently scheduled to
begin in April 2027 and would occur on approximately 238 days over a
12-month period. However, project delays may occur due to a number of
factors, including project funding, permitting requirements,
availability of equipment and/or materials, weather-related delays,
equipment maintenance and/or repair, transit to and from ports to
survey locations, and other contingencies. Work is expected to be
conducted for up to 12-hours on any given day.

Specific Geographic Region

The proposed project would occur on the eastern shore of Gastineau
Channel, adjacent to downtown Juneau, AK (see figure 1). The Juneau
waterfront is heavily influenced by industrialization, characterized by
a blend of heavy marine industrial activities and significant tourism
infrastructure. The waterfront supports commercial seafood processing,
fishing, and, historically, major mining operations. Marine mammals
within the area are

[[Page 64892]]

consistently subjected to commercial and recreational vessel traffic,
most notably large cruise ships.
[GRAPHIC] [TIFF OMITTED] TN13OC26.000

Detailed Description of the Specified Activity

CBJ proposes to extend the existing seawalk from the Franklin Dock
to the AJ Dock and install a cruise ship mooring dolphin with access
catwalks. Construction includes removal of existing pile-supported
docks, floats, and mooring dolphins and miscellaneous abandoned timber
piles; installation and removal of temporary template construction
piles; and installation of piles to support the new seawalk, cruise
ship mooring dolphin, and access catwalks.
Removal of Existing Docks and Piles
Prior to construction of the new seawalk and cruise ship mooring
dolphin CBJ would demolish the existing National Guard Dock and Moorage
Float and National Guard Approach Dock and remove the supporting timber
piles; remove two mooring dolphins supported by 24-inch and 36-inch
steel pipe piles; and remove miscellaneous abandoned timber piles. All
piles would be removed using a vibratory hammer if they cannot be
removed via direct pull methods. See table 1 for summary of pile
installation and removal details.
Seawalk Construction
The seawalk would be constructed using two-, three-, and four-pile
bents, comprised of approximately 230 24-inch steel pipe piles. The
piles would be initially installed with vibratory methods and then
proofed for proper penetration and load capacity with an impact hammer.
Three 24-inch steel pipe piles would similarly be installed using both
vibratory and impact methods in support of a catwalk. A cruise ship
mooring dolphin, supported by five 42-inch steel pipe piles, would be
installed using both vibratory and impact methods. Mooring dolphin
piles that do not achieve the required embedment to resist loads will
require the installation of 10-inch rock sockets with DTH drilling.
Approximately 160 template piles would be installed and removed using
vibratory methods in support of construction of seawalk piles and
mooring dolphin. CBJ anticipates the use of two template piles per bent
along the seawalk and four template piles in support of each mooring
dolphin pile. See table 1 for pile installation and removal details.

[[Page 64893]]

Table 1--CBJ Seawalk Extension Project Summary of Pile Installation and Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated
Project component Pile size/type Installation/removal Number of Average piles Maximum piles number of days
method piles per day per day \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
National Guard Dock and Moorage Float 10- to 16-inch timber Vibratory Removal...... 40 10 12 \b\ 7
piles.
National Guard Approach Dock......... 10- to 16-inch timber Vibratory Removal...... 4 2 4 2
piles.
Miscellaneous timber piles........... 10- to 16-inch timber Vibratory removal...... 20 2 10 \b\ 14
piles.
Mooring dolphin...................... 24-inch steel pipe pile. Vibratory removal...... 12 3 12 4
Mooring dolphin...................... 36-inch steel pipe pile. Vibratory removal...... 4 1 4 4
--------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary Pile Installation and Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
Template piles....................... 24-inch steel pipe pile. Vibratory Installation 320 (160 4 12 80
and Removal. installed, 160
removed)
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New Pile Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Seawalk support piles................ 24-inch steel pipe piles Vibratory and impact... 230 2 7 115
Catwalk support piles................ 24-inch steel pipe piles Vibratory and impact... 3 2 3 2
Mooring dolphin...................... 42-inch steel pipe piles Vibratory and impact... 5 1 3 5
Mooring dolphin...................... 10-inch rock socket..... DTH drilling........... 5 1 2 5
---------------------------------------------------------------
Total............................ ........................ ....................... .............. .............. .............. 238
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Average number of piles per day used to determine estimated number of pile driving days.
\b\ Estimated number of days were calculated by dividing the total number of piles by the average number of piles per day. For the National Guard Dock
and Moorage Float and the miscellaneous timber piles, 4 days and 3 days were added to this number, respectively, to account for the possibility that
some of the deteriorated piles might break during extraction, requiring more time for removal.

Existing armor rock slope protection may require temporary removal
to facilitate pile installation, which would be conducted using a
clamshell bucket or excavator. The armor rock would be replaced around
the piles following installation. Excavation and fill activities are
not expected to result in take of marine mammals.
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 likely 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 mortality and serious injury (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. 2024 SARs. All values presented in table 2 are the most
recent available at the time of publication (including from the 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 64894]]

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\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae (rorquals):
Humpback Whale.................. Megaptera novaeangliae. Hawai[revaps]i......... -, -, N 11,278 (0.56, 7,265, 127 27.09
2020).
Family Delphinidae:
Killer Whale.................... Orcinus orca........... Eastern North Pacific -, -, N 1,920 (N/A, 1,920, 19 1.3
Alaska Resident. 2019) \ 5\.
Killer Whale.................... Orcinus orca........... Eastern North Pacific -, -, N 587 (N/A, 587, 2012) 5.9 0.8
Gulf of Alaska, \5\.
Aleutian Islands and
Bering Sea Transient.
Killer Whale.................... Orcinus orca........... Eastern North Pacific -, -, N 302 (N/A, 302, 2018) 2.2 0.2
Northern Resident. \5\.
Killer Whale.................... Orcinus orca........... West Coast Transient... -, -, N 349 (N/A, 349, 2018) 3.5 0.4
\5\.
Family Phocoenidae (porpoises):
Harbor Porpoise................. Phocoena phocoena...... Northern Southeast -, -, N 1,619 (0.26, 1,250, 13 5.6
Alaska Inland Waters. 2019).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
sea lions):
Steller Sea Lion................ Eumetopias jubatus..... Western................ E, D, Y 49,837 (N/A, 49,837, 299 267
2022) \ 6\.
Steller Sea Lion................ Eumetopias jubatus..... Eastern................ -, -, N 36,308 (N/A, 36,308, 2,178 93.2
2022) \ 6\.
Family Phocidae (earless seals):
Harbor Seal..................... Phoca vitulina......... Lynn Canal/Stephens -, -, N 13,388 (N/A, 11,883, 214 50
Passage. 2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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>).
\2\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\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; Nmin 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, vessel strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.
\5\ Stock abundance is based upon counts of individuals identified from photo-ID catalogs.
\6\ Stock abundance is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates are provided for
the United States only.

As indicated above, all five species (with nine managed stocks) in
table 2 temporally and spatially co-occur with the specified activity
to the degree that take is likely to occur. While minke whales (Balaena
acutorostrata), Dall's porpoise (Phocoenoides dalli), and Pacific
white-sided dolphins (Lagenorhynchus obliquidens) have been documented
in the area, the temporal and/or spatial occurrence of these species is
such that take is not expected to occur, and they are not discussed
further.
Only about 2 percent of the humpback whales in the project area are
expected to be from the Mexico-North Pacific stock (Wade, 2021). Given
the low occurrence of humpback whales in the area, the likelihood of
take of the Mexico-North Pacific stock is extremely low (see Estimated
Take of Marine Mammals section below) and, therefore, take of this
stock is neither expected nor proposed.
Large portions of southeast Alaska have been identified as humpback
whale biologically important areas (BIAs) for seasonal feeding due to
the species' dependence on foraging resources in the region. The BIAs
are active from April through October to overlap with the highest
densities of humpback whales and their prey (Wild et al., 2023). The
narrow Gastineau Channel, where CBJ proposes to conduct construction,
is positioned between the Juneau BIA to the north and the Frederick
Sound & Stephens Passage BIA to the south and is not located with an
area considered to be of importance for humpback whale foraging.
In addition, the northern sea otter (Enhydra lutris kenyoni) may be
found in Juneau, AK. However, sea otters are managed by the U.S. Fish
and Wildlife Service and are not considered further in this document.

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 approximately 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). In October
2024, NMFS published its 2024 Updated Technical Guidance, which
includes updated thresholds and weighting functions to inform auditory
injury estimates and

[[Page 64895]]

replaces the 2018 Technical Guidance referenced above. This 2024
Updated Technical Guidance represents the best available science.
Marine mammal hearing groups and their associated hearing ranges are
provided in table 3.

Table 3--Marine Mammal Hearing Groups
[NMFS, 2024]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 hertz (Hz) to 36 kilohertz
whales). (kHz)
High-frequency (HF) cetaceans (dolphins, 150 Hz to 160 kHz
toothed whales, beaked whales, bottlenose
whales).
Very High-frequency (VHF) cetaceans (true 200 Hz to 165 kHz
porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus cruciger
& L. australis).
Phocid pinnipeds (PW) (underwater) (true 40 Hz to 90 kHz
seals).
Otariid pinnipeds (OW) (underwater) (sea 60 Hz to 68 kHz
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 discusses how 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.
There are a variety of types and degrees of effects on marine
mammals, prey species, and habitats that could result from the project.
Below is a brief description of the sound sources the projects would
generate, the general impacts of these activities, and an analysis of
the anticipated impacts on marine mammals from the projects, with
consideration of the proposed mitigation measures.

Description of Sound Sources

Impact hammers typically operate by repeatedly dropping and/or
pushing a heavy piston onto a pile to drive the pile into the
substrate. Sound generated by impact hammers is impulsive,
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 hammer's weight to
drive them into the substrate. Vibratory hammers typically produce less
sound (i.e., lower levels) 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, Caltrans, 2015, 2020). Sounds produced by
vibratory hammers are non-impulsive; compared to sounds produced by
impact hammers, the rise time is slower, reducing the probability and
severity of injury, and the sound energy is distributed over a greater
amount of time (Nedwell and Edwards, 2002, Carlson et al., 2005).
DTH systems use a combination of percussive and drilling
mechanisms, with the hammer acting directly on the rock to advance a
hole into the rock and also advance the pile into that hole. The hammer
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). Therefore, DTH systems include both
impulsive and continuous components. For this project, CBJ would
utilize DTH drilling to install 10-inch rock sockets.

Potential Effects of Underwater Sound on Marine Mammals

The introduction of anthropogenic noise into the aquatic
environment from vibratory pile removal, vibratory and impact pile
installation, and DTH drilling are the means by which marine mammals
may be harassed from CBJ's specified activities. Anthropogenic sounds
span a broad range of frequencies and sound levels and can have highly
variable impacts on marine life, from none or minor to potentially
severe responses, depending on received levels, duration of exposure,
behavioral context, and other factors. Broadly, underwater sound from
active acoustic sources, such as those in these projects, can
potentially result in one or more of the following: temporary or
permanent hearing impairment, non-auditory physical or physiological
effects, behavioral disturbance, stress, and masking (Richardson et
al., 1995, Nowacek et al., 2007, Southall et al., 2007, G[ouml]tz et
al., 2009).
We describe the more severe effects of certain non-auditory
physical or physiological effects only briefly, as we do not expect
that the use of impact/vibratory hammers is reasonably likely to result
in such effects (see below for further discussion).
Potential physiological effects from sound sources, particularly
impulsive sound, can range from behavioral disturbance or tactile
perception to physical discomfort, slight injury to the internal organs
and the auditory system, or mortality (Yelverton et al., 1973). Non-
auditory physiological effects or injuries that theoretically might
occur in marine mammals exposed to high level underwater sound or as a
secondary effect of extreme behavioral reactions (e.g., change in dive
profile as a result of an avoidance reaction) caused by exposure to
sound include neurological effects, bubble formation, resonance
effects, and other types of organ or tissue damage (Cox et al., 2006,
Southall et al., 2007, Zimmer and Tyack, 2007, Tal et al., 2015).
However, the project activities considered here do not involve the use
of devices such as explosives or mid-frequency tactical sonar that are
associated with these types of effects.
In general, animals exposed to natural or anthropogenic sound may
experience physical and psychological effects, ranging in magnitude
from none to severe (Southall et al., 2007, 2019). Exposure to
anthropogenic noise can result in auditory threshold shifts and
behavioral responses (e.g., avoidance, temporary cessation of foraging
and vocalizing, changes in dive behavior). It

[[Page 64896]]

can also lead to non-observable physiological responses, such as
increased stress hormone levels. Additional noise in a marine mammal's
habitat can mask acoustic cues used in daily functions, such as
communication and predator and prey detection.
The degree of effect of an acoustic exposure on marine mammals is
dependent on several factors, including, but not limited to, sound type
(e.g., impulsive vs. non-impulsive), signal characteristics, the
species, age, and sex class (e.g., adult male vs. mom with calf),
duration of exposure, the distance between the noise source and the
animal, received levels, behavioral state at time of exposure, and
previous history with exposure (Wartzok et al., 2004, Southall et al.,
2007). In general, sudden, high-intensity sounds can cause hearing
loss, as can longer exposures to lower-intensity sounds. Moreover, any
temporary or permanent loss of hearing, if it occurs at all, would
occur almost exclusively for noise within an animal's hearing range. We
describe below the specific manifestations of acoustic effects that may
occur from the specified activities.
Richardson et al. (1995) described zones of increasing effect
intensity that might be expected to occur with distance from a source,
assuming that the signal is within an animal's hearing range. First (at
the greatest distance) is the area within which the acoustic signal
would be audible (potentially perceived) to the animal but not strong
enough to elicit any overt behavioral or physiological response. The
next zone (closer to the receiving animal) corresponds to the area
where the signal is audible to the animal and sufficiently intense to
elicit behavioral or physiological responsiveness. The third is a zone
within which, for high-intensity signals, the received level is
sufficient to cause discomfort or tissue damage to auditory or other
systems. Overlaying these zones to some extent is the area within which
masking (i.e., when a sound interferes with or masks an animal's
ability to detect a signal of interest above the absolute hearing
threshold) may occur; the masking zone may vary widely in size.
Hearing Threshold Shifts
NMFS defines a noise-induced threshold shift (TS) as a change,
usually an increase, in the audibility threshold at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018, 2024). The amount
of threshold shift 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), the 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, the time to recovery (seconds to minutes
or hours to days), the frequency range of the exposure (i.e., spectral
content), the hearing frequency range of the exposed species relative
to the signal's frequency spectrum (i.e., how the 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).
Temporary Threshold Shift
A temporary threshold shift (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, 2024) and is not considered an auditory injury
(AUD INJ). Based on data from marine mammal TTS measurements (see
Southall et al., 2007, 2019), a TTS of 6 dB is considered the minimum
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Finneran et
al., 2000, 2002, Schlundt et al., 2000). As described in Finneran
(2015), marine mammal studies have shown that the amount of TTS
increases with the 24-hour cumulative sound exposure level
(SEL<INF>24</INF>) in an accelerating fashion: at low exposures with
lower SEL<INF>24</INF>, the amount of TTS is typically small, and the
growth curves have shallow slopes. At higher SEL<INF>24</INF>
exposures, the growth curves become steeper and approach a linear
relationship with the sound exposure level (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 more impactful (similar to those discussed in
auditory masking, below). For example, a marine mammal may readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that occurs while the animal is traveling
through the open ocean, where ambient noise is lower and competing
sounds are fewer. Alternatively, a larger amount and longer duration of
TTS sustained during times when communication is critical for
successful mother/calf interactions could have more severe impacts. We
note that reduced hearing sensitivity, as a simple function of aging,
has been observed in marine mammals, as well as in humans and other
taxa (Southall et al., 2007), suggesting that strategies exist to cope
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, so the sound must be louder to be heard. In
terrestrial and marine mammals, TTS can last from minutes to hours (in
cases of strong TTS) (Finneran, 2015). 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 (Delphinapterus
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis) (Southall et al., 2019). For pinnipeds in water,
measurements of TTS are limited to harbor seals, northern elephant
seals (Mirounga angustirostris), bearded seals (Erignathus barbatus),
and California sea lions (Zalophus californianus) (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 in
marine mammals before and after exposure to intense or long-duration
sound. 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 depend on the exposure frequency.
Sounds below the region of best sensitivity for a species or hearing
group are less hazardous than those 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

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species (Finneran, 2015). In addition, TTS can accumulate across
multiple exposures, but the resulting TTS would be lower than that 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, SEL<INF>24</INF>, will overestimate
the amount 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 whale, and false killer whale (Pseudorca
crassidens)) when a warning sound preceded a relatively loud 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 enable conditioned hearing reduction and filtering of low-
frequency ambient noise, including increased stiffness and control of
middle ear structures, as well as placement of inner ear structures
(Ketten et al., 2021). Data available on noise-induced hearing loss for
mysticetes are currently lacking (NMFS, 2024). Additionally, the
existing marine mammal TTS data come from a limited number of
individuals within these species.
Relationships between TTS and permanent threshold shift (PTS)
thresholds have not been studied in marine mammals, and there are no
measured 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 dB 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 AUD
INJ 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 AUD INJ 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 AUD
INJ could occur.
Auditory Injury and Permanent Threshold Shift
NMFS (2024) defines AUD INJ as damage to the inner ear that can
result in tissue destruction, such as loss of cochlear neuron synapses
or auditory neuropathy (Houser, 2021, Finneran, 2024). AUD INJ may or
may not result in PTS. PTS is defined 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 generally affects only a limited
frequency range, and animals with PTS have some level of hearing loss
at the relevant frequencies; typically, animals with PTS or other AUD
INJ 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 the onset of PTS (see Ward et al.,
1958, 1959, Ward, 1960, Kryter et al., 1966, Miller, 1974, Ahroon et
al., 1996, Henderson et al., 2008). However, a variety of terrestrial
and marine mammal studies (see Ward et al., 1958, 1959, Ward, 1960,
Miller et al., 1963, Kryter et al., 1966, Southall et al., 2007,
Kastelein et al., 2013) indicate that threshold shifts of up to 40 to
50 dB (measured a few minutes after exposure) may be induced without
resulting in PTS. PTS levels for marine mammals are estimates; with the
exception of a single study unintentionally inducing PTS in a harbor
seal (Kastak et al., 2008), no empirical data measure PTS in marine
mammals largely due to the fact that, for various ethical reasons,
experiments involving anthropogenic noise exposure at levels inducing
AUD INJ are not typically pursued or authorized (NMFS, 2024). NMFS has
set the PTS onset as an initial threshold shift of 40 dB.
However, after sound exposure ceases or between successive sound
exposures, the potential for recovery from hearing loss exists. Thus,
because a threshold shift is measured a few minutes after noise
exposure does not mean that those initial shifts are persistent (i.e.,
no recovery). When initial threshold shifts fully recover back to
baseline hearing levels, these are considered TTS. PTS indicates there
is no full recovery back to baseline hearing levels; however, it does
not mean there is no recovery. Rather, PTS indicates incomplete
recovery of hearing. Recovery depends on the initial threshold shift
amount, the frequency at which the shift occurred, the temporal pattern
of exposure (e.g., exposure duration; continuous vs. intermittent
exposure), and the physiological mechanisms underlying the shift (e.g.,
mechanical vs. metabolic). Since recovery is complicated, our current
AUD INJ onset criteria do not account for the potential for recovery.
Behavioral Effects
Exposure to noise can also behaviorally disturb marine mammals to a
level that rises to the definition of harassment under the MMPA.
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 a behavioral disturbance,
and for responses that do, those of higher level or longer duration
have the potential to affect foraging, reproduction, or survival.
Behavioral disturbance may include subtle changes (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); and avoiding of areas where sound sources
are located. In addition, 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

[[Page 64898]]

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.
As noted above, behavioral state may affect the type of response.
For example, resting animals 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, 2005). Controlled
experiments with captive marine mammals have shown 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 (e.g., (Erbe et al., 2019). If a marine mammal briefly
reacts to an underwater sound by changing its behavior or moving a
small distance, the resulting change is unlikely to be significant to
the individual, let alone the stock or population. 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, National
Research Council, 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 on breathing, interference with or alteration of vocalization,
avoidance, and flight.
Avoidance and Displacement
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, Blair et al., 2016).
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 in dive behavior
resulting from acoustic exposure depends on what the animal is doing at
the time of exposure and on 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. 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, the relationship
between prey availability, foraging effort, and success, and the
animal's life history stage.
Respiration rates vary naturally with different behaviors, and
alterations in 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 of
understanding species differences in the 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 rates increased in
response to pile driving sounds at and above a received broadband SPL
of 136 dB (zero-peak SPL: 151 dB re 1 micropascal ([mu]Pa); SEL of a
single strike (SEL<INF>ss</INF>): 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 due to 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). 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 the abundance or distribution patterns of the
affected species in the affected region if habituation to 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, with
directed, rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
its intensity (e.g., directed movement and travel rate). Relatively
little information exists on the flight responses of marine mammals to
anthropogenic signals, although observations of flight responses to the
presence of predators have been made (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 affect marine mammals in more
subtle ways. Increased vigilance may incur costs from the diversion of
attention (i.e., when a response requires heightened vigilance, it may
come at the expense of reduced attention to other critical behaviors,
such as foraging or resting). These effects have generally not been
demonstrated in marine mammals, but studies of 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 reductions in fitness (e.g., declines in body condition) and
subsequent reductions 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 result
in sleep deprivation or stress.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions

[[Page 64899]]

resulting from reactions to stressors, such as sound exposure, is more
likely to be significant if it lasts more than 1 diel cycle or recurs
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 multiple days does not necessarily mean that
individual animals are exposed to activity-related stressors for
multiple days, or, further, exposed in a manner that results in
sustained, multi-day, substantive behavioral responses.
Physiological Stress Responses
An animal's perception of a threat may be sufficient to trigger
stress responses that include some combination of behavioral, autonomic
nervous system, neuroendocrine, and immune responses (e.g., Selye,
1950, Moberg, 2000). In many cases, an animal's first and sometimes
most economical response (in terms of energetic costs) 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 pituitary hormone secretion have been implicated in
reproductive failure, altered metabolism, reduced immune competence,
and behavioral disturbances (e.g., Moberg, 1987, Blecha, 2000).
Increases in glucocorticoid levels are also associated 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 its glycogen
stores, which 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 will last until the animal replenishes its energy
reserves to a sufficient level 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, Ayres et al., 2012, Yang
et al., 2021). Stress responses 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. In addition, Lemos et al. (2022)
observed a correlation between higher levels of fecal glucocorticoid
metabolite concentrations (indicative of a stress response) and vessel
traffic in gray whales. Yang et al. (2021) studied behavioral and
physiological responses in captive bottlenose dolphins exposed to
playbacks of ``pile-driving-like'' impulsive sounds, finding
significant changes in cortisol and other physiological indicators, but
only minor behavioral changes. These and other studies lead to a
reasonable expectation that some marine mammals will experience
physiological stress responses upon exposure to acoustic stressors, and
that some of these responses may be classified as ``distress.'' In
addition, any animal experiencing TTS would likely also experience
stress responses (National Research Council, 2005); however, distress
is unlikely to result from these projects based on observations of
marine mammals during previous, similar construction projects in
southeast Alaska.
Vocalizations and Auditory Masking
Since many marine mammals rely on sound to find prey, moderate
social interactions, and facilitate mating (Tyack, 2008), noise 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 specific frequencies for marine
mammals that rely on 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).
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 the
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, including modifications of the acoustic
properties of the signal or the signaling behavior (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. Few studies have addressed real-
world masking sounds likely to be experienced by marine mammals in the
wild (e.g., Branstetter et al., 2013).
Masking occurs in the frequency band that the animals use and is
more likely to occur in the presence of broadband, relatively
continuous noise sources such as vibratory pile removal or
installation. The energy distribution of pile-driving sound spans a
broad frequency spectrum and is expected to fall within the audible
range of marine mammals present in the project areas. Since noises
generated from the proposed construction activities are mostly
concentrated at low frequencies (<2 kHz), these activities likely have
less effect on mid-frequency echolocation sounds produced by
odontocetes (toothed whales). However, lower-frequency noises are more
likely to

[[Page 64900]]

affect the detection of communication calls and other potentially
important natural sounds, such as surf and prey noise. Low-frequency
noise may also affect communication signals when they occur near the
noise band, thereby reducing the communication space of animals (e.g.,
Clark et al., 2009) and increasing stress levels (e.g., Holt et al.,
2009). Unlike TS, masking, which can occur over large temporal and
spatial scales, can potentially affect the species at population,
community, or even ecosystem levels, in addition to individual levels.
Masking affects both senders and receivers of signals, and at higher
levels and for longer durations could have long-term chronic effects on
marine mammal species and populations. However, the noise generated by
the CBJ's proposed activities would occur only intermittently across
238 days in a relatively small area focused around the proposed
construction sites. Thus, while the CBJ's proposed activities may mask
some acoustic signals 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
affected.
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 across any of these modes and may result from a need to
compete with increased 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 (Balaenoptera physalus) have
also been documented to lower the bandwidth, peak frequency, and center
frequency of their vocalizations in the presence of increased
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 that exposed
them to vessel noise, have been observed to increase their vocalization
rate and produce louder signals during periods of increased outboard
engine noise (Dahlheim and Castellote, 2016). Alternatively, in some
cases, animals may cease sound production during the production of
aversive signals (Bowles et al., 1994, Wisniewska et al., 2018).
Under certain circumstances, marine mammals that experience
significant masking could also be impaired in maximizing their
performance fitness for survival and reproduction. Therefore, when the
coincident (masking) sound is human-made, it may be considered
harassment if it disrupts or alters 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 associated with
harassment). Therefore, under certain circumstances, marine mammals
whose acoustic sensors or environment are severely masked could also be
impaired in maximizing their performance fitness for survival and
reproduction.
Airborne Acoustic Effects
Pinnipeds occurring near the project site could be exposed to
airborne sounds associated with construction activities, depending on
their distance from these activities, which could cause behavioral
harassment. Airborne noise would primarily be an issue for pinnipeds
that are swimming or hauled out near either project site, within the
range of noise levels elevated above the airborne acoustic harassment
criteria. Cetaceans are not expected to be exposed to airborne sounds
that would result in harassment as defined under the MMPA.
We recognize that pinnipeds in the water may be exposed to airborne
sound that could result in behavioral harassment when they lift their
heads above the water or when they haul out. 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 a reduction in vocalizations, or to flush from
haulouts, temporarily abandon the area, and/or move further from the
source. However, these animals previously would have been ``taken''
because of exposure to underwater sound above the behavioral 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,
authorization of additional incidental take resulting from airborne
sound for pinnipeds was not requested by CBJ, and NMFS has determined
is not warranted; airborne sound is not discussed further here.

Potential Effects on Marine Mammal Habitat

CBJ's specified activities could have localized, temporary impacts
on marine mammal habitat, including prey, due to increased in-water
noise levels and water quality degradation. Increased noise levels may
affect the acoustic habitat and adversely affect marine mammal prey in
the vicinity of the project areas (see discussion below). Elevated
levels of underwater noise would ensonify the project areas where both
fishes and mammals occur and could affect foraging success.
Additionally, marine mammals may avoid the area during the proposed
construction activities; however, any displacement due to noise is
expected to be temporary and not to result in long-term effects on
individuals or populations. A temporary reduction in water quality is
expected due to disruption of sediment and increased turbidity, but
long-term effects to marine mammals and their prey is not expected (see
Water Quality section below).
The total area impacted by CBJ's proposed activities is relatively
small compared to the available habitat within southeast Alaska. While
marine mammals may forage in Gastineau Channel near the project area,
the waters ensonified do not contain unique or particularly important
habitat relative to other waters in southeast Alaska. Moreover, the
Juneau waterfront area where the project would occur is industrialized.
The proposed project would occur within the same footprint as
existing marine infrastructure. The nearshore and intertidal habitats
where the proposed projects would occur are in industrialized areas
with relatively high marine vessel traffic. Temporary, intermittent,
and short-term habitat alteration may result from increased noise
levels during the proposed construction activities, including temporary
displacement of prey species. Although installation of new piles
represents a permanent alteration to the marine habitat, the alteration
is minor and limited in space and would not affect the survival of
marine mammals or their prey.

[[Page 64901]]

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 removal and installation of piles, when bottom
sediments are disturbed, and may temporarily increase suspended
sediment in the project area. During pile extraction, sediment attached
to the pile moves vertically through the water column causing a
sediment plume. However, since currents are so strong in the area,
following the completion of sediment-disturbing activities, suspended
sediment in the water column should dissipate and quickly return to
background levels across all construction scenarios.
Turbidity in the water column can reduce dissolved oxygen levels
and irritate the gills of prey fish in the proposed project areas.
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). However, turbidity plumes associated with the projects
would be temporary and localized, and fish in the proposed project
areas would be able to move away from and avoid the areas where plumes
may occur.
Overall, the water quality in the immediate area that is likely
impacted by the proposed construction activities for both projects is
relatively small compared to the available marine mammal habitat within
and surrounding Juneau, and the effects would be temporary. Therefore,
it is expected that water quality impacts on prey species due to
turbidity, and therefore on marine mammals, would be minimal and
temporary.
Potential Effects on Prey
Sound may affect marine mammals by altering the abundance,
behavior, or distribution of prey species (e.g., crustaceans,
cephalopods, fishes, zooplankton). Marine mammal prey varies by
species, season, and location, and for some, it is not well documented.
Studies regarding the effects of noise on known marine mammal prey are
described here.
Avoidance by potential prey (i.e., fish) of the immediate areas due
to increased noise is possible. The duration of avoidance of this area
after construction stops is unknown, but a rapid return to normal
recruitment, distribution, and behavior is anticipated. Any behavioral
avoidance by fish would still leave significantly large areas of fish
and marine mammal foraging habitat in the nearby vicinity.
Fishes use 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 and detect the motion of surrounding water
(Fay et al., 2008). The potential effects of noise on fishes depend on
the overlapping frequency range, distance from the sound source, water
depth of exposure, and species-specific hearing sensitivity, anatomy,
and physiology. Key impacts on fishes may include behavioral responses,
hearing damage, barotrauma (pressure-related injuries), and mortality.
Fish react to 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 their physiological state, 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
fishes (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., Pe[ntilde]a et
al., 2013, Wardle et al., 2001, Jorgenson and Gyselman, 2009, Cott et
al., 2012). More commonly, though, the impacts of noise on fishes are
temporary.
SPLs of sufficient strength have been known to cause injury to
fishes and fish mortality (summarized in Popper et al., 2014). However,
in most fish species, hair cells in the ear continuously regenerate,
and loss of auditory function is likely restored when damaged cells are
replaced with new cells. Halvorsen et al. (2012b) showed that a TTS of
4-6 dB was recoverable within 24 hours in one species. Impacts would be
most severe when the individual fish is near the source, and the
exposure duration is long. Injury caused by barotrauma can range from
slight to severe and cause death; risk of injury is higher for fish
with swim bladders. Barotrauma injuries have been documented during
controlled exposure to impact pile driving (Halvorsen et al., 2012a,
Casper et al., 2013, 2017).
Fish populations in the proposed project area that serve as prey
for marine mammals could be temporarily affected by noise from pile
removal and installation. The frequency range in 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 in response to strong and/or intermittent sounds
that could harm fish. 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).
Zooplankton is a food source for several marine mammal species, as
well as a food source for fish that are then preyed upon by marine
mammals. Population effects on zooplankton could indirectly affect
marine mammals. Data are limited on the effects of underwater sound on
zooplankton species, particularly sound from construction (Erbe et al.,
2019). Popper and Hastings (2009) reviewed information on the effects
of human-generated sound and concluded that no substantive data are
available on whether sound levels from pile driving, seismic activity,
or other human-made sources would have physiological effects on
invertebrates. Any such effects would be limited to the area very near
(1 to 5 meters [m]) the sound source and would result in no population
effects because of the relatively small area affected at any one time
and the reproductive strategy of most zooplankton species (short
generation, high fecundity, and very high natural mortality). No
adverse impact on zooplankton populations is expected from the
specified activities, due in part to their large reproductive capacity
and naturally high levels of predation and mortality. Any mortalities
or impacts that might occur would be negligible.
The greatest potential acoustic impact on marine mammal prey during
construction would occur during impact pile driving. Vibratory pile
removal/installation may elicit behavioral responses in fishes, such as
temporary avoidance of the area, but is unlikely to cause injuries to
fishes or have persistent effects on local fish populations. In-water
construction

[[Page 64902]]

activities would only occur during daylight hours, allowing fish to
forage and transit the project area in the evening. Construction would
also have minimal permanent and temporary impacts on benthic
invertebrate species, a marine mammal prey source.
Potential Effects on Foraging Habitat
The proposed project activities are not expected to result in any
habitat-related effects that could cause significant or long-term
negative consequences for individual marine mammals or their
populations, since removal and installation of in-water piles would be
temporary and intermittent. The area affected by these activities is
relatively small compared to the available habitat just outside the
project areas, and neither project would affect any areas of particular
importance. Any behavioral avoidance by fish in the disturbed areas
would still leave significantly large areas of fish and marine mammal
foraging habitat in the nearby vicinity. As described in the preceding,
the potential for the CBJ's activities to affect the availability of
prey to marine mammals or to meaningfully impact the quality of
physical or acoustic habitat is considered to be insignificant.
Therefore, the impacts of the project activities are not likely to
adversely affect marine mammal foraging habitat in the proposed project
area.
In summary, given the relatively small areas being affected, as
well as the temporary and mostly transitory nature of the proposed
construction activities, any adverse effects from CBJ's activities on
prey habitat or prey populations are expected to be primarily minor and
temporary although some fish injury or mortality may occur (e.g.,
Hastings and Popper, 2005). The most likely impact on fishes at the
project sites would be temporary avoidance of the area. Any behavioral
avoidance by fish in the disturbed areas would still leave
significantly large areas of fish and marine mammal foraging habitat in
the nearby vicinity. Thus, we conclude that the impacts of the
specified activities are not likely to have more than short-term
adverse effects on any prey habitat or populations of prey species.
Further, any impacts on 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 the acoustic sources (i.e., vibratory and impact pile driving and
DTH drilling) has the potential to result in disruption of behavioral
patterns for individual marine mammals. There is also some potential
for AUD INJ (Level A harassment) to result for two species of marine
mammals (Steller sea lions and harbor seals). 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). Below, we describe the thresholds used by CBJ and
NMFS for this analysis.
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared sound pressure levels (RMS SPL) of 120 dB (referenced to 1
micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g.,
scientific sonar) sources. Generally speaking, Level B harassment take
estimates based on these behavioral harassment thresholds are expected
to include any likely takes by TTS as, in most cases, the likelihood of
TTS occurs at distances from the source less than those at which
behavioral harassment is likely. TTS of a sufficient degree can
manifest as behavioral harassment, as reduced hearing sensitivity and
the potential reduced opportunities to detect important signals
(conspecific communication, predators, prey) may result in changes in
behavior patterns that would not otherwise occur.
CBJ's proposed activities include the use of continuous (vibratory
pile driving and DTH drilling) and impulsive (impact pile driving and
DTH drilling) sources, and therefore the RMS SPL thresholds of 120 and
160 dB re 1 [mu]Pa 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)

[[Page 64903]]

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) (see table 4). CBJ's activities
include the use of impulsive (impact pile driving and DTH drilling) and
non-impulsive (vibratory pile driving and DTH drilling) sources.
The 2024 Updated Technical Guidance criteria include both updated
thresholds and updated weighting functions for each hearing group. The
thresholds are provided in the table 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
----------------------------------------------------------------------------------------------------------------
LF Cetaceans........................... Cell 1: Lpk,flat: 222 dB; Cell 2: LE,LF,24h: 197 dB.
LE,LF,24h: 183 dB.
HF Cetaceans........................... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,HF,24h: 201 dB.
LE,HF,24h: 193 dB.
VHF Cetaceans.......................... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,VHF,24h: 181 dB.
LE,VHF,24h: 159 dB.
PW (Underwater)........................ Cell 7: Lpk,flat: 223 dB; Cell 8: LE,PW,24h: 195 dB.
LE,PW,24h: 183 dB.
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 peak SPL (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 [micro]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 project. Marine
mammals are expected to be affected via sound generated by the primary
components of the project (i.e., vibratory and impact pile driving and
DTH drilling).
The project includes vibratory pile installation and removal,
impact pile installation, and DTH drilling. Source levels for these
activities are based on reviews of measurements of the same or similar
types and dimensions of piles available in the literature. Source
levels for each pile size and activity 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--Proxy Sound Source Levels
----------------------------------------------------------------------------------------------------------------
Source level (at 10 m)
------------------------------------------------
Pile size and type Peak (dB re 1 RMS (dB re 1 SEL (dB re 1 Reference
[mu]Pa) [mu]Pa) [mu]Pa2 sec)
----------------------------------------------------------------------------------------------------------------
Vibratory
----------------------------------------------------------------------------------------------------------------
10- to 16-inch timber pile......... N/A 162 N/A Caltrans (2020).
24-inch steel pipe pile............ N/A 163 N/A U.S. Navy (2012, 2013),
Miner (2020).*
36-inch steel pipe pile............ N/A 166 N/A U.S. Navy (2012, 2013),
Sexton (2007), Laughlin
(2011, 2017), Miner (2020)
*
42-inch steel pipe piles........... N/A 170 N/A Reyff and Heyvaert (2019).*
----------------------------------------------------------------------------------------------------------------
Impact
----------------------------------------------------------------------------------------------------------------
24-inch steel pipe piles........... 203 190 177 Caltrans (2015).
42-inch steel pipe piles........... 208 195 180 Caltrans (2020)--Russian
River Geyersville, CA;
Terminal Replacement,
Antioch, CA, Illingworth &
Rodkin (2017)-
Philadelphia, PA; Austin
et al., (2016).*
----------------------------------------------------------------------------------------------------------------
DTH
----------------------------------------------------------------------------------------------------------------
10-inch rock socket................ 172 167 146 Guan and Miner (2020),
Reyff and Heyvaert (2019),
and Reyff (2020) as cited
in NMFS (2022).
----------------------------------------------------------------------------------------------------------------
* Methodology followed U.S. Navy (2015) and included available data from Puget Sound, Washington, and Southern
Alaska.

[[Page 64904]]

DTH systems have both continuous, non-impulsive, and impulsive
components. When evaluating Level B harassment, NMFS recommends
treating DTH as a continuous source and applying RMS SPL thresholds of
120 dB re 1 [mu]Pa, and when evaluating Level A harassment, NMFS
recommends treating DTH as an impulsive source (NMFS, 2022).
Transmission loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from space. 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 (R<INF>1</INF>/R<INF>2</INF>)

Where:

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

This formula neglects loss due to scattering and absorption, which
is assumed to be zero here. The degree to which underwater sound
propagates away from a sound source depends on various factors, most
notably the water bathymetry and the presence or absence of reflective
or absorptive conditions, including in-water structures and sediments.
Spherical spreading occurs in a perfectly unobstructed (free-field)
environment not limited by depth or water surface, resulting in a 6 dB
reduction in sound level for each doubling of distance from the source
(20*log[range]). Cylindrical spreading occurs in an environment in
which sound propagation is bounded by the water surface and sea bottom,
resulting in a reduction of 3 dB in sound level for each doubling of
distance from the source (10*log[range]). A practical spreading value
of 15 is often used in coastal waters, such as those found in the CBJ
Seawalk project area. In these environments, sound waves repeatedly
reflect off the surface and bottom, reflecting an expected propagation
environment between spherical and cylindrical spreading-loss
conditions. Therefore, the default coefficient of 15 is used to
calculate distances to the Level A harassment and Level B harassment
isopleths.
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 a practical, alternative way to estimate isopleth distances when
more sophisticated modeling methods are not available or practical. For
stationary sources, such as vibratory and impact pile driving and DTH
drilling, 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 AUD INJ. Inputs used in the
optional User Spreadsheet tool (table 6), and the resulting estimated
isopleths (table 7), are reported below.

Table 6--User Spreadsheet Input Parameters Used for Calculating Level A Harassment Isopleths for Pile Driving and DTH Drilling
--------------------------------------------------------------------------------------------------------------------------------------------------------
Piles per day Duration Strikes per Strikes per
Project component Pile size/type Hammer \a\ (minutes) \b\ pile second
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
National Guard Dock and Moorage Float 10- to 16-inch timber Vibratory.............. 12 30 N/A N/A
piles.
National Guard Approach Dock......... 10- to 16-inch timber Vibratory.............. 4 60 N/A N/A
piles.
Miscellaneous timber piles........... 10- to 16-inch timber Vibratory.............. 10 30 N/A N/A
piles.
Mooring dolphin...................... 24-inch steel pipe piles Vibratory.............. 12 45 N/A N/A
Mooring dolphin...................... 36-inch steel pipe piles Vibratory.............. 4 60 N/A N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Template piles....................... 24-inch steel pipe piles Vibratory.............. 12 45 N/A N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
New Pile Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Seawalk support...................... 24-inch steel pipe piles Vibratory.............. 7 100 N/A N/A
Impact................. 7 N/A 2,000 N/A
Catwalk support...................... 24-inch steel pipe piles Vibratory.............. 3 120 N/A N/A
Impact................. 3 N/A 1,200 N/A
Mooring dolphin...................... 42-inch steel pipe pile. Vibratory.............. 3 180 N/A N/A
Impact................. 3 N/A 3,000 N/A
Mooring dolphin...................... 10-inch rock socket..... DTH drilling........... 2 120 N/A 15
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ CBJ used the maximum number of piles that could be installed or removed per day (see table 1).
\b\ CBJ used the average amount of time expected per pile for installation or removal per day.

Table 7--Calculated Distances to Level A Harassment and Level B Harassment Isopleths for Pile Driving and DTH Drilling
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment zones (m) \a\ Level B
Project component Pile size/type Hammer ----------------------------------------------------------------- harassment
LF HF VHF PW OW zone (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
National Guard Dock and Moorage 10- to 16-inch Vibratory.......... 36 14 29 46 15 \b\ 6,310
Float. timber piles.

[[Page 64905]]

National Guard Approach Dock.... 10- to 16-inch Vibratory.......... 27 10 22 35 12 \b\ 6,310
timber piles.
Miscellaneous timber piles...... 10- to 16-inch Vibratory.......... 31 12 26 40 14 \b\ 6,310
timber piles.
Mooring dolphin................. 24-inch steel pipe Vibratory.......... 54 21 44 70 24 \b\ 7,356
piles.
Mooring dolphin................. 36-inch steel pipe Vibratory.......... 50 19 41 64 22 \b\ 11,659
piles.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Template piles.................. 24-inch steel pipe Vibratory.......... 54 21 44 70 24 \b\ 7,356
piles.
--------------------------------------------------------------------------------------------------------------------------------------------------------
New Pile Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Seawalk support................. 24-inch steel pipe Vibratory.......... 65 25 53 83 28 \b\ 7,356
piles.
Impact............. 2,301 294 \b\ 3,561 2,044 762 1,000
Catwalk support................. 24-inch steel pipe Vibratory.......... 41 16 34 53 18 \b\ 7,356
piles.
Impact............. 930 119 1,440 827 308 1,000
Mooring dolphin................. 42-inch steel pipe Vibratory.......... 159 61 130 205 69 \b\ 21,544
piles.
Impact............. 2,716 347 \b\ 4,204 2,413 900 2,154
Mooring dolphin................. 10-inch rock socket DTH drilling....... 122 16 189 109 41 \b\ 13,594
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Level A harassment isopleths are conservative because the maximum number of piles per day were used to calculate the isopleths.
\b\ These isopleths are truncated by land at approximately 3,550 m during high tide. During low tide, these isopleths are truncated by land at
approximately 2,230 m.

As described above, NMFS uses dual metric criteria for impulsive
sounds (impact pile driving) when determining onset of AUD INJ (Level A
harassment), using either the PK SPL or weighted cumulative sound
exposure level (SEL<INF>24</INF>) and recommends using the larger
isopleth. In table 7 above, all Level A harassment isopleths are based
on the SEL<INF>24</INF> metric. The PK SPL Level A harassment isopleths
were less than 10 m for all hearing groups for all impact pile driving
scenarios except for VHF cetaceans. The PK SPL Level A harassment
isopleths for VHF cetaceans were 12 m for the impact installation of
the seawalk and catwalk support piles and 25 m for the impact
installation of the mooring dolphin 42-inch steel pipe piles. For DTH
installation of the 10-inch rock socket, the PK SPL Level A harassment
isopleth based on the peak threshold was considered N/A for all hearing
groups because the peak source level is less than the threshold for
that marine mammal hearing group.

Marine Mammal Occurrence

In this section we provide information about the occurrence of
marine mammals, including density or other relevant information which
will inform the take calculations.
Density estimates are not readily available for the project area;
therefore, CBJ reviewed marine mammal monitoring reports for
construction conducted in the same area, citizen science reports from
<a href="http://inaturalist.com">inaturalist.com</a> and <a href="http://happywhale.com">happywhale.com</a>, and anecdotal evidence. More
information regarding occurrence data and sources cited can be found in
section 6 of CBJ's application.
Humpback whale--Humpback whales are relatively common in southeast
Alaska, especially during the summer, but they are seen in Gastineau
Channel relatively rarely, with only occasional sightings (PND
Engineers, 2026). One humpback whale was seen in March during
monitoring for the Downtown Waterfront Improvements Project (Uchytil et
al., 2020). During monitoring for other projects in Gastineau Channel,
no humpback whales were seen (Michrowski and Easterly, 2025, Uchytil
and Michrowski, 2021, Michrowski et al., 2021), although these projects
were all conducted during fall and winter months when humpback whales
are less likely to be in the area. Because anecdotal reports and
citizen science suggest that humpback whales pass through the project
area intermittently (PND Engineers, 2026), particularly in summer
months, CBJ conservatively assumes that three individual whales will
occur per month, and NMFS concurs.
Killer whale--Killer whales are occasionally seen transiting
through Gastineau Channel. During 58 days of marine mammal monitoring
for the Downtown Juneau Waterfront Improvements Project, a group of 4
killer whales was observed (Uchytil et al., 2020). Reports indicate
occasional sightings of killer whales in Gastineau Channel, with a
group of at least seven animals seen near downtown Juneau in January
2020 and May 2021 (<a href="http://happywhale.com">happywhale.com</a>). CBJ therefore conservatively
assumes one group of seven killer whales could occur per month during
construction, and NMFS concurs with this approach.
Harbor porpoise--Harbor porpoise are relatively uncommon in
Gastineau Channel. Additionally, harbor porpoises can be very cryptic,
making reports of harbor porpoises in Gastineau Channel relatively
scarce. During marine mammal monitoring for the Downtown Juneau
Waterfront Improvements Project, a group of four harbor porpoises were
observed (Uchytil et al., 2020). In February 2024, a pair of harbor
porpoises were spotted near the Juneau-Douglas Bridge (Woodford, 2024).
CBJ conservatively estimates that one group of four harbor porpoises
will occur in CBJ's construction area per month, and NMFS concurs with
this approach.
Steller sea lion--During 58 days of monitoring for the Downtown
Waterfront Improvement project, eight Steller sea lions were observed
on 1 day (Uchytil et al., 2020), and one Steller sea lion was observed
during the Wayside Park Float and Dredging project in December of 2024
(Michrowski and Easterly, 2025). The Douglas Island Pink and Chum, Inc.
salmon hatchery is located along the Gastineau Channel, approximately
5.5 kilometers (km) northwest of CBJ's project area. Hatchery staff
report that during the months of July through September, they see one
to two Steller sea lion per day (PND Engineers, 2026). Given the
proximity of the CBJ project area to the hatchery (which attracts
Steller sea lions) and likelihood that Steller sea lions would pass
through CBJ's project area, CBJ assumes that two Steller sea

[[Page 64906]]

lions per day would be present in CBJ's project area, and NMFS concurs.
Harbor seal--Harbor seals are one of the most frequently sighted
marine mammals in the project area. Over the course of 58 days of
monitoring for the Downtown Juneau Waterfront Improvements Project in
2020, harbor seals were present in the project area on most days, and
the monitoring report suggests that a resident group of around 10-12
harbor seals uses Gastineau Channel in the winter (Uchytil et al.,
2020). In total, there were 164 observations of harbor seals within the
Level B harassment isopleth throughout the course of monitoring. Over 2
days of monitoring for the Harris Harbor Pile Driving project in
February 2021, a total of 26 harbor seals were observed, and observers
estimated that approximately three to five resident harbor seals
comprised the bulk of the recorded sightings (Michrowski et al., 2021).
CBJ conducted pre-construction monitoring of a 130 m shutdown zone for
the Downtown Juneau Waterfront Improvements Projects, and an average of
18 harbor seals were observed per day (PND Engineers, 2019). CBJ
therefore assumes 18 harbor seals per day in the project area, and NMFS
concurs with this approach.

Take Estimation

Here we describe how the information provided above is synthesized
to produce a quantitative estimate of the take that is reasonably
likely to occur and proposed for authorization.
In general, the formula for determining the number of takes that
may occur incidental to CBJ's proposed project is:

Total take by harassment = occurrence estimate (in days) x pile
activity days (238 days)

For species where occurrence was estimated as a number of
individuals per month, CBJ assumed 30 days per month and converted the
monthly occurrence to daily occurrence by dividing the monthly
occurrence by 30. When the calculated number had a decimal, the number
was rounded down when below 0.5 and up when greater than or equal to
0.5. See table 8 for estimated takes.

Table 8--Estimated Monthly and Daily Marine Mammal Occurrence During
CBJ's Proposed Project
------------------------------------------------------------------------
Monthly Daily
Species occurrence occurrence
------------------------------------------------------------------------
Humpback whale................................ 3 0.1
Killer whale.................................. 7 0.23
Harbor porpoise............................... 4 0.13
Steller sea lion.............................. N/A 2
Harbor seal................................... N/A 18
------------------------------------------------------------------------

To determine the number of takes that may occur by Level A
harassment, NMFS considered sound sources, calculated distance to
thresholds assuming the maximum number of piles per day would be
installed, and species detectability and behavior. For vibratory pile
installation and removal, it is unlikely that Level A harassment would
occur due to relatively lower source levels and that threshold were
either not exceeded or calculated distances to thresholds were small.
Therefore, all takes calculated incidental to these activities were
attributed to Level B harassment.
Similarly, NMFS does not expect nor does it propose take by Level A
harassment for killer whales for any activity. The calculated distances
to Level A harassment thresholds for killer whales is relatively short
(see table 7) and represents extended durations. Because an animal is
unlikely to remain in such close proximity to the piles for that time,
AUD INJ is unlikely to occur. Further, killer whales are a highly
visible species such that PSOs are likely to detect them and implement
mitigation to avoid take by Level A harassment. Some of the Level A
harassment isopleths for humpback whales due to impact pile driving are
relatively large (approximately 2.3 km for impact installation of the
seawalk support piles and 2.7 km for impact installation of 42-inch
steel pipe piles (see table 7). CBJ proposes to shut down impact pile
driving for humpback whales at 2,000 m for these piles. We expect
humpback whales to be highly visible for protected species observers
(PSOs) to implement shutdown, and we do not expect that humpback whales
would remain in the area between the furthest extent of the Level A
harassment isopleth and the shutdown zone long enough to incur AUD INJ.
For other piles and DTH drilling, the calculated distances to the Level
A harassment threshold are less than 2 km. Therefore, no Level A
harassment of humpback whales is anticipated and none is proposed to be
authorized.
The best available science demonstrates that harbor porpoises are
behaviorally sensitive species and exhibit strong reactions to
impulsive noise such as impact pile driving. For example, displacement
of harbor porpoises has been observed during impact pile driving
associated with the construction at multiple offshore wind projects
(Tougaard et al., 2009, Bailey et al., 2010, D[auml]hne et al., 2013,
Lucke et al., 2012, Haelters et al., 2015, Brandt et al., 2018). These
studies document long-distance (i.e., several kilometers) displacement;
however, the duration of displacement has been documented to generally
be temporary. The piles involved in coastal construction projects are
smaller than those in these studies; however, other data support
predicted avoidance responses wherein porpoise move away from a man-
made sound source; thereby reducing accumulated noise energy. For
example, Kok et al. (2018) found that two captive harbor porpoises
spatially avoided a noisy pool when exposed to intermittent or
continuous sound stimuli. In summary, harbor porpoises are likely to
avoid coastal construction-related sound sources associated with the
project to the degree that AUD INJ is unlikely. For these reasons, NMFS
is not proposing to authorize Level A harassment of harbor porpoise.
Take by Level A harassment is proposed for authorization for
Steller sea lions and harbor seals primarily because Level A harassment
isopleths are relatively large for impact pile driving and DTH drilling
(up to approximately 2.4 km for phocids and 900 m for otariids for
impact pile driving of the 42-inch steel pipe pile), visibility of
these species is such that we would not expect PSOs to observe them at
such a large distance, and it is possible these species could remain in
the area between the furthest extent of the Level A harassment zone and
the shutdown zone to incur AUD INJ.
To determine the number of takes by Level A harassment for Steller
sea lions and harbor seals, CBJ first considered the number of days
that Level A harassment might occur and considered this to be days of
impact pile driving and DTH drilling where the Level A harassment zone
is larger than the shutdown zone. CBJ estimates the number of days in
which harbor seals might incur Level A harassment to be 127 days (5
days for impact installation of 42-inch steel pipe piles, 2 days of
impact installation of 24-inch steel catwalk piles, 115 days of impact
installation of 24-inch seawalk support piles, and 5 days of DTH
drilling) and for Steller sea lions, CBJ estimates 120 days (5 days for
impact installation of 42-inch pipe piles and 115 days of

[[Page 64907]]

impact installation of the 24-inch steel seawalk support piles).
Steller sea lions are not expected to incur Level A harassment on days
of DTH drilling because the Level A harassment isopleth for Steller sea
lions during DTH drilling is only 41 m, and we expect PSOs to institute
shutdown before this species would enter the Level A harassment
isopleth. The Level A harassment isopleth for harbor seals during DTH
drilling, on the other hand, is 109 m. The shutdown zone for phocids
has been set to 25 m for practicability concerns (see Proposed
Mitigation section below), and therefore we expect that harbor seals
could incur Level A harassment. CBJ then estimated the number of takes
by Level A harassment by multiplying the daily occurrence estimate by
120 days for Steller sea lions and 127 days for harbor seals.
To estimate the number of takes by Level B harassment, CBJ used the
following equation:
Takes by Level B harassment = Total take by harassment-Takes by
Level A harassment
NMFS acknowledges that the number of estimated exposures above
higher threshold criteria using the methodology (e.g., sound exposures
exceeding Level A harassment criteria), also encompasses the potential
for less impactful effects (e.g., Level B harassment). An individual
exposure exceeding a Level A harassment criterion may not result in
actual AUD INJ, yet the individual may have experienced Level B
harassment. This outcome is accounted for in our authorization of
potential higher-level takes and in our analysis.
Where multiple stocks of a single species may be present, NMFS
considered the best available science to determine the percentage of
takes by stock. Both the Hawai'i and Mexico-North Pacific stocks of
humpback whale occur in the project area. However, only about 2 percent
of the humpback whales in the area are expected to be from the Mexico-
North Pacific stock, as described in Wade (2021). Because the total
calculated takes of humpback whales in the area are 24, the calculated
number of humpback whales from the Mexico-North Pacific stock would be
less than 0.5 whales. Therefore, we do not expect humpback whales from
the Mexico-North Pacific Stock to be taken by harassment incidental to
the specified activities.
In the Juneau area, about 1.4 percent of Steller sea lions are
expected to be from the Western stock (NOAA Fisheries, 2020), and the
remainder are expected to be from the Eastern stock. Therefore, to
determine the number of takes that may occur to Steller sea lions from
the Western stock, the total number of takes by Level A harassment
(240) and Level B harassment (236) were multiplied by 1.4 percent and
rounded to the nearest whole number. The remainder of takes by Level A
and Level B harassment were attributed to the Eastern stock of Steller
sea lions (see table 9).
Sufficient data does not exist to predict the likelihood of each
stock of killer whale in the project area. Therefore, NMFS assumes that
the proposed takes could be attributed to any of the stocks in the
area.

Table 9--Number of Takes, by Level A and Level B Harassment, Proposed for Authorization
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated Estimated Total
Species Stock Stock takes by Level takes by Level instances of Percent of
abundance A harassment B harassment take Stock \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale............................ Hawai[revaps]i.............. 11,278 0 24 24 0.2
Killer whale.............................. Eastern North Pacific Alaska 1,920 0 55 55 2.9
Resident.
Eastern North Pacific Gulf 587 9.4
of Alaska, Aleutian Island,
and Bering Sea Transient.
Eastern North Pacific 302 18.2
Northern Resident.
West Coast Transient........ 349 15.8
Harbor porpoise........................... Northern Southeast Alaska 1,619 0 31 31 1.9
Inland Water.
Steller sea lion.......................... Western..................... 49,837 3 3 6 <0.1
Eastern..................... 36,308 237 233 470 1.3
Harbor seal............................... Lynn Canal/Stephens Passage. 13,388 2,286 1,998 4,284 \b\ 32
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ The values presented here are based on calculations assuming all takes were from a different individual. However, repeated takes of the same
individual are more likely to occur for species remaining within the area to forage or those that display increase site fidelity (e.g., harbor seals).
Therefore, the actual percentage of the population taken is likely less than that provided here.
\b\ Harbor seals in Gastineau Channel display site fidelity, and there is a group of resident harbor seals within Gastineau Channel (see Marine Mammal
Occurrence section above). Therefore, repeated takes of an individual are likely, and the actual percentage of the population is likely less than what
is provided here.

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, as
well as subsistence uses. This considers the

[[Page 64908]]

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 CBJ in
its adequate and complete application or are the result of subsequent
coordination between NMFS and CBJ. CBJ 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 which is available for review 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>.

Establishment of Clearance and Shutdown Zones

CBJ proposed, and NMFS would require, the establishment of
clearance and shutdown zones identified in table 10 for all pile
driving and DTH activities. The purpose of ``clearance'' of a
particular zone is to prevent potential instances of auditory injury
and more severe behavioral disturbance the maximum extent practicable
by delaying the commencement of pile driving or DTH drilling if marine
mammals are detected within certain pre-defined distances from the pile
being installed. The purpose of a shutdown is to prevent a specific
acute impact, such as auditory injury or severe behavioral disturbance,
by halting the activity if a marine mammal is to approach or enter the
Level A harassment isopleth. Additionally, to avoid unauthorized takes,
CBJ would delay an activity or shut down in the event that a species
for which take is not authorized or for which take has been reached is
observed within or entering any designated harassment zone. If pile
driving or DTH activities are 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 clearance and shutdown zones indicated in table 10 or 15 minutes
have passed without re-detection of the animal.
In-water construction activities that do not include the specified
activities but require heavy equipment will also shut down if a marine
mammal approaches within 10 m to avoid direct interaction.
In general, the clearance and shutdown zones represent the
calculated Level A harassment distance rounded up for ease of
implementation. However, a maximum shutdown zone of 2,000 m for low
frequency cetaceans and 300 m for very high frequency cetaceans and
otariids will be maintained due to detectability and/or practicability.
In addition, CBJ is proposing a maximum 25 m clearance and shutdown
zone be maintained for harbor seals. Data collected by CBJ in 2019
during pre-construction monitoring for the Downtown Juneau Waterfront
Improvement Project indicates that extended mitigation zones would not
be practicable as harbor seals are frequently observed in close
proximity (within 130 m) to the project site such that the specified
activities would not be able to commence or continue to the degree that
the project could be completed within reasonable time frames (PND
Engineers, 2019). For that project, harbor seal presence close to the
pile driving location resulted in CBJ requesting a modified IHA to
reduce original harbor seal shutdown zone sizes from 130 m to 25 m
(<a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-juneau-waterfront-improvement-project-juneau-alaska">https://www.fisheries.noaa.gov/action/incidental-take-authorization-juneau-waterfront-improvement-project-juneau-alaska</a>), and they have
applied that experience to this project. NMFS has determined that
clearance and shutdown zones beyond 25m for harbor seals is not
practicable and could result in delays such that noise-generating
activities associated with the project would be unnecessarily extended.

Table 10--Proposed Shutdown/Clearance Zones From Source (m)
----------------------------------------------------------------------------------------------------------------
Pile size/type LF HF VHF PW OW
----------------------------------------------------------------------------------------------------------------
Vibratory
----------------------------------------------------------------------------------------------------------------
10- to 16-inch timber piles..... 40 15 30 25 15
24-inch steel pipe piles........ 65 25 55 25 30
36-inch steel pipe piles........ 50 20 45 25 25
42-inch steel pipe piles........ 160 65 130 25 70
----------------------------------------------------------------------------------------------------------------
Impact
----------------------------------------------------------------------------------------------------------------
Seawalk support piles (24-inch 2,000 295 300 25 300
steel pipe piles)..............
Catwalk support piles (24-inch 930 120 300 25 300
steel pipe piles)..............
42-inch steel pipe piles........ 2,000 350 300 25 300
----------------------------------------------------------------------------------------------------------------
DTH Drilling
----------------------------------------------------------------------------------------------------------------
10-inch rock socket............. 125 20 190 25 45
----------------------------------------------------------------------------------------------------------------

Pre- and Post-Activity Monitoring

Monitoring would take place from 30 minutes prior to initiation of
pile driving and DTH drilling (pre-start clearance monitoring) through
30 minutes post-completion of pile driving and DTH drilling. In
addition, monitoring for 30 minutes would take place whenever a break
in the specified activity (i.e., impact or vibratory pile driving or
DTH drilling) of 30 minutes or longer occurs. Pre-start clearance
monitoring would be conducted during periods of visibility sufficient
for protected species observers (PSOs) to

[[Page 64909]]

determine that the clearance zones indicated in table 10 are clear of
marine mammals. Pile driving and DTH drilling may commence following 30
minutes of observation when the determination is made that the
clearance zones are clear of marine mammals.

Soft Start

CBJ would use soft start procedures for impact pile driving to
provide additional protection to marine mammals by issuing a warning
and/or giving them a chance to leave the area before the hammer
operates at full capacity. 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.
This soft start would be implemented at the start of each day's impact
pile driving and at any time following cessation of this activity for a
period of 30 minutes or longer within a day.

Bubble Curtains

CBJ has not proposed to use a bubble curtain during impact pile
driving due to limited effectiveness of the bubble curtains due to the
strong tides in the area and economic impracticability. In general,
bubble curtains reduce noise levels near the source, minimizing
exposure level. However, for this project, most of the piles are
located within the intertidal zone, and for a significant number of
piles the upper limits of the bubble curtain would be above the water
surface preventing the bubble curtains from being effective. In
addition, requiring the use of a bubble curtain would reduce the number
of piles that could be installed in a day due to the time it takes to
install and move the device. Therefore, the duration over which the
project would occur would be extending, increasing project costs and
exposing marine mammals to underwater sound over longer time periods.
For these reasons, CBJ has determined that the use of a bubble curtain
is not practicable, and NMFS agrees.
NMFS conducted an independent evaluation of the proposed measures
and 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, areas of similar significance,
and on the availability of such species or stock for subsistence uses.
Specific proposed mitigation measures can be found in the draft IHA
found 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>.

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 CBJ in its adequate and complete application
and/or are the result of subsequent coordination between NMFS and CBJ.
CBJ has agreed to the requirements. NMFS describes these below as
requirements and has included them in the proposed IHA.
CBJ would abide by all monitoring and reporting measures contained
within the IHA, if issued, and their Protected Species Mitigation and
Monitoring Plan (see NMFS' website 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>).

Visual Monitoring

A minimum of one NMFS-approved PSO would be assigned to each active
pile driving and DTH drilling location, and at least two NMFS-approved
PSOs would be on duty during all pile driving and DTH drilling
activities. PSOs would be independent of the activity contractor (for
example, employed by a subcontractor) and have no other assigned tasks
during monitoring periods. At least one PSO would have prior experience
performing the duties of a PSO during an activity pursuant to a NMFS
issued Incidental Take Authorization (ITA) or Letter of Concurrence
(LOC). Other PSOs may substitute other relevant experience (including
relevant 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. Where a team of three or
more PSOs is required a lead observer or monitoring coordinator would
be designated. The lead observer must have prior experience performing
the duties of a PSO during construction activity pursuant to a NMFS-
issued ITA or LOC.

Reporting

CBJ would submit a draft report on all construction activities and
marine mammal monitoring results to NMFS within 90 days of the
completion of monitoring, or 60 days prior to the requested issuance of
any subsequent IHAs or similar activity at the same location, whichever
comes first. CBJ will provide a final report to NMFS within 30 days
following resolution of NMFS' comments on the draft report. The
information required to be collected and reported to NMFS is included
in the draft IHA available 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>. In summary, the report would include, but not be limited
to, information regarding activities that occurred, marine mammal
sighting data,

[[Page 64910]]

and whether mitigative actions were taken or could not be taken. CBJ
would also be required to submit reports on any observed injured or
dead marine mammals. If the death or injury was clearly caused by a
specified activity, the CBJ would 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. CBJ would
not resume its activities until notified by NMFS.
Specific proposed monitoring and reporting measures can be found in
the draft IHA found 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>.

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
species listed in table 9 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.
Specifically, the specified activities may result in take, in the
form of Level A harassment and/or Level B harassment, from underwater
sounds generated from pile driving and DTH drilling. Potential takes
could occur if individuals of these species are present in zones
ensonified above the thresholds for Level A harassment and/or Level B
harassment identified above when these activities are underway. CBJ
would implement mitigation measures designed to reduce the potential
for and severity of harassment that effect the least practicable
adverse impact on the affected marine mammal species and stocks during
the specified activities. Given the nature of the proposed activities,
NMFS does not anticipate serious injury or mortality due to CBJ's
specified activities, even in the absence of required mitigation.
For all species and stocks, take is expected to occur within a
limited, confined area (adjacent to the project site) of the species'
range, including Southeast Alaska. The intensity and duration of take
by Level A harassment and/or Level B harassment would be minimized
through the proposed mitigation measures described herein. Furthermore,
the number of takes proposed for authorization is small compared to the
relative stock's abundance, even assuming that every take for any
particular species could wholly occur to individuals of an individual
stock.
NMFS is proposing to authorize take, by Level A harassment, for two
marine mammal species (Steller sea lions and harbor seals) incidental
to the specified activities. As described in the Potential Effects to
Marine Mammals and Their Habitat section, the impacts could be a small
degree of AUD INJ which may or may not manifest as PTS. Should PTS
occur, at most, NMFS anticipates it would be of a small degree;
therefore, NMFS anticipates a sound would have to be only slightly
louder for it to be heard by an individual that may incur PTS from the
project. Further, PTS would only occur within the frequency range of
the source (i.e., impact pile driving, DTH drilling) which does not
cover any species' complete hearing range. For most species, the
frequency range of the noise produced by the specified activities is
outside their primary hearing range.
Additionally, as noted previously, some subset of individuals who
are behaviorally harassed during the activities could also
simultaneously incur some small degree of TTS for a short duration.
However, because of the anticipated small degree of possible overlap of
sound exposure, duration, and hearing frequency with species
occurrence, any TTS is expected to be limited.
Behavioral responses of marine mammals to pile removal and
installation activities in the project area, if any, are expected to be
mild, short-term, and temporary. Marine mammals within the Level B
harassment zones may not show any visual cues that they are disturbed
by activities, or they may become alert, avoid the area, leave the
area, or display other mild responses that are not observable, such as
changes in vocalization patterns. Additionally, many of the species
present in the region would be present only temporarily, based on
seasonal patterns or during active transit between other habitats. Most
likely, during the specified activities, individuals are expected to
move away from the sound source until the source ceases. An avoidance
response is most likely to occur if an animal is in close proximity to
a source, most notably impact pile driving and DTH drilling. At
distance, the severity of any behavioral response is likely to be
diminished from all of the specified activities. It is possible that
avoidance or other behavioral responses do not occur for some species,
especially for non-impulsive sources such as vibratory pile removal and
driving, given marine mammals in the Juneau area are consistently
exposed to anthropogenic noise sources like vessel traffic. Regardless,
NMFS conservatively assumes animals disturbed by project sounds would
be expected to avoid the area and use nearby higher-quality habitats.
Further, pinnipeds in the area would be able to haul out to avoid
underwater noise exposure.
Although the majority of marine mammal species would be temporarily
passing through the project area, there is likely a small group of
resident harbor seals in Gastineau Channel, as described in previous
monitoring reports (Uchytil et al., 2020, Michrowski et al., 2021).
These animals may be taken repeatedly during construction. However,
because these animals are habituated to the industrialized waters
around Juneau, it is unlikely that repeated takes would occur either in
numbers or clumped across sequential days in a manner likely to impact
foraging success and energetic or other behaviors such that

[[Page 64911]]

reproduction or survival of any individuals is likely to be impacted.
For humpback whales, the inland waters of Southeast Alaska are a
seasonal feeding BIA from May through September (Wild et al., 2023).
However, the Gastineau Channel, where CBJ proposes to conduct their
construction, is not included within this feeding BIA. Thus, neither
the proposed activities nor the ensonified areas from CBJ's proposed
activities would have overlap with this foraging habitat, and we do not
expect CBJ's proposed activities to have any effect on humpback whale's
ability to forage.
The potential and severity of harassment is minimized by
implementing the proposed mitigation measures. During all pile removal
and installation activities, CBJ would delay commencement of or
shutdown activities if a marine mammal is observed within designates
zones to minimize instance and severity of behavioral harassment and
injury. These zones would be monitored by NMFS-approved PSOs. Further,
prior to impact pile driving, CBJ will implement a soft-start of the
equipment prior to operating at maximum energy. Given sufficient notice
through soft start, marine mammals are expected to move away from a
sound source to avoid the loudest noise exposure, thereby reducing the
intensity of any behavioral reactions or injury that may occur.
Any impact on marine mammal habitat, including prey, from CBJ's
proposed activities would primarily have temporary effects primarily
resulting in increased turbidity and avoidance of the immediate
vicinity around the project site by prey. Some injury or mortality of
fish prey may occur if exposed to sufficiently high SPLs; however,
these more severe impacts are expected to be minimal, if any at all.
Addition of the new seawalk and cruise ship mooring dolphin would
result in permanent impacts; however, these and the expected temporary
impacts are not expected to adversely affect the degree to which marine
mammals can efficiently forage.
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
authorized;
<bullet> Any Level A harassment (AUD INJ) is anticipated to be
slight AUD INJ, including slight PTS of a few dB within the lower
frequencies associated with pile driving and not encompassing a
species' full hearing range;
<bullet> The anticipated incidents of Level B harassment would
result in, at worst, temporary modifications in behavior or a small
degree of TTS that would resume to baseline at the cessation of
activities or as animals move away from the source;
<bullet> The project area is located in a highly industrialized and
commercial area; therefore, species taken are likely acclimated to
anthropogenic activities and behavioral reactions are expected to be
temporary and of low severity;
<bullet> Take would occur within a very small area affected by the
specified activity relative to the overall habitat ranges of all
species, and it does not include any rookeries, ESA-designated critical
habitat, or BIAs;
<bullet> Effects on species that serve as prey for marine mammals
from the activities are primarily 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 adverse impacts on their populations; and
<bullet> The proposed mitigation measures, such as soft-starts for
impact pile driving and implementation of clearance and shutdown zones,
are expected to reduce the effects of the specified activity to the
least practicable adverse impact level.
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 (see 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.
The amount of take NMFS proposes to authorize is below one-third of
the estimated stock abundances for all stocks (table 9). Calculations
are assuming that all takes were from a different individual. However,
as described in the Marine Mammal Occurrence section, there is a group
of resident harbor seals in Gastineau Channel. It is, therefore,
likely, that repeated takes of harbor seals would occur, and that the
percentage of the Lynn Canal/Stephens Passage stock of harbor seals is
likely less than the calculated 32 percent.
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.
Alaska Natives have traditionally harvested subsistence resources,
including sea lions and harbor seals, in Southeast Alaska. Surveys of
harbor seal and sea lion subsistence harvest in Alaska began in 1992,
and since 2001, there has been a discernible decrease in households
harvesting harbor seals. In the period from 1992 to 2001, the counts of
households harvesting harbor seals ranged from 246 to 310 households
each year, but since 2001 the counts of harvesters ranged from 138 to
205 households (Wolfe et al., 2013). In 2012 (the last reported survey
year), the count of harvesters was the second lowest it

[[Page 64912]]

had ever been at 140 households (Wolfe et al., 2013). Throughout all
the years of subsistence surveys, hunting effort for sea lions has
remained at a low level, with only 4 households reporting to hunt sea
lions in 2012 (Wolfe et al., 2013). In 2012, the community of Juneau
harvested 23 harbor seals and no sea lions (Wolfe et al., 2013).
The Alaska Department of Fish and Game has designated the area
around Juneau, including ensonified waters from the project, a non-
subsistence area, defined as an area where dependence upon subsistence
(customary and traditional uses of fish and wildlife) is not a
principal characteristic of the economy, culture, and way of life (AS
16.05.258(c)). Regardless, the impact of the project on marine mammals
is expected to be primarily limited to mild behavioral reactions (e.g.,
avoidance during pile activities, increased swim speeds, or cessation
of vocalizations) such that it would not affect their availability for
subsistence use.
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 CBJ'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
Alaska Regional Office (AKRO).
NMFS Office of Protected Resources (OPR) is proposing to authorize
take of the western stock of Steller sea lions, which are listed under
the ESA. OPR has requested initiation of section 7 consultation with
AKRO 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 CBJ allowing for the incidental take of marine mammals
incidental to the Seawalk Extension Project in Juneau, AK, 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/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</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: October 7, 2026.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2026-20789 Filed 10-9-26; 8:45 am]
BILLING CODE 3510-22-P

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