Notice2026-04857
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Port of Adak Pier 5 Improvements Project at Adak Island, Alaska
Primary source
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Published
March 12, 2026
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from The Aleut Corporation (TAC) for authorization to take marine mammals incidental to the Port of Adak Pier 5 Improvements Project (hereafter referred to as the Pier 5 Improvements Project), Adak Island, Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an incidental harassment authorization (IHA) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, 1-year renewal that could be issued under certain circumstances and if all requirements are met, as described in the Request for Public Comments section 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 48 (Thursday, March 12, 2026)</title>
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[Federal Register Volume 91, Number 48 (Thursday, March 12, 2026)]
[Notices]
[Pages 12148-12171]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-04857]
[[Page 12148]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XF200]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Port of Adak Pier 5
Improvements Project at Adak Island, 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 Aleut Corporation (TAC)
for authorization to take marine mammals incidental to the Port of Adak
Pier 5 Improvements Project (hereafter referred to as the Pier 5
Improvements Project), Adak Island, Alaska. Pursuant to the Marine
Mammal Protection Act (MMPA), NMFS is requesting comments on its
proposal to issue an incidental harassment authorization (IHA) to
incidentally take marine mammals during the specified activities. NMFS
is also requesting comments on a possible one-time, 1-year renewal that
could be issued under certain circumstances and if all requirements are
met, as described in the Request for Public Comments section 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 April
13, 2026.
ADDRESSES: Comments should be addressed to Howard Goldstein, Biologist,
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#5b120f0b751c34373f282f3e32351b35343a3a753c342d"><span class="__cf_email__" data-cfemail="0f465b5f214860636b7c7b6a66614f61606e6e21686079">[email protected]</span></a>. Electronic copies of the application and
supporting documents, as well as a list of the references cited in this
document, may be obtained online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>. 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: Howard Goldstein, Office of Protected
Resources, NMFS, (301) 427-8417.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of the takings are set forth. The definitions
of all applicable MMPA statutory terms cited above are included in the
relevant sections below.
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.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA request.
Investing in Infrastructure and Jobs Act
The Pier 5 Improvements Project is published on the Federal
Permitting Dashboard as a Department of Transportation project.
Requirements for publication and tracking on the Federal Permitting
Dashboard include a suite of provisions designed to expedite the
environmental review, including enhanced interagency coordination as
well as milestone tracking. The Pier 5 Improvements Project page,
including milestones and schedules related to the environmental review
and permitting for the project can be found at: <a href="https://www.permits.performance.gov/permitting-project/dot-projects/port-adak-pier-five-improvements-project">https://www.permits.performance.gov/permitting-project/dot-projects/port-adak-pier-five-improvements-project</a>.
Summary of Request
On August 6, 2025, NMFS received a request from TAC for an IHA to
take marine mammals incidental to pile removal and installation
activities associated with the Pier 5 Improvements Project at Adak
Island, Alaska. Following NMFS' review of the application, and
discussions between NMFS and TAC, TAC submitted a revised application
on February 11, 2026, which NMFS deemed adequate and complete on March
2, 2026. TAC's request is for take of five species of marine mammals,
by Level B harassment and Level A harassment. Neither TAC nor NMFS
expect serious injury or mortality to result from this activity and
none is proposed to be authorized; therefore, an IHA is appropriate.
[[Page 12149]]
Description of Proposed Activity
Overview
TAC is proposing to fix and modernize the fender and piling system
at Pier 5 on Adak Island, Alaska, to current industry and safety
standards as well as upgrade the pier lighting and utilities. The
project would remove the existing timber pile fender system, timber
wale top rail, steel egress ladders, under-deck catwalk system, and
abandoned pipelines and related utilities and infrastructure; and would
replace the damaged concrete pier support piles and the entire timber
fender system with a heavy-duty steel pile (circular pipe-shaped) and
fender sleeve assembly with greater capacity for absorbing energy from
berthing vessels. The current footprint of the pier or pier deck would
not be altered. The project would enable goods to be more efficiently
and safely loaded and unloaded from small/large commercial and military
vessels and allow for the safe embarking/disembarking of the vessel's
crew, which would support the local and regional economy as well as the
seafood industry. The pier also includes a NOAA data collection
structure as well as serves as an oil spill response storage hub.
Pier 5, which was constructed by the U.S. Navy in 1980, is 730 feet
(ft) (222.5 meters [m]) long with concrete decking consisting of
precast concrete panels and concrete topping/wear surface. The initial
165 ft (50.3 m) is 40 ft (12.2 m) wide and the next 565 ft (172.2 m) is
90 ft wide (27.4 m). Pier 5 and the surrounding infrastructure are
remnants of the former Adak Naval Air Station and have experienced
significant wear due to harsh environmental conditions and limited
maintenance since military decommissioning. Due to the condition of the
current fender and piling system at Pier 5, both large and small
commercial and military vessels that have called on or been interested
in calling on the Port of Adak have been unable to moor or had
complications when mooring. Additionally, the electrical, firewater,
potable water, and wastewater systems on Pier 5 have been abandoned in
place and have not been repaired or upgraded. Limited electrical
service is provided to a NOAA data collection structure, accessed by
galvanized steel stairs on either side of Pier 5.
The Port of Adak also serves as an oil spill response hub for the
Alaska Chadux Network, an industry-funded non-profit oil spill response
organization headquartered in Anchorage, Alaska. The unmanned equipment
stored at the Port of Adak would be used for oil spill response for
vessels passing through the Great Circle Route from North America to
Asia. Pier 5 cannot currently support the movement of equipment and
must rely on nearby Adak airfield to fly in response personnel.
The specified activities that have the potential to result in take
of marine mammals include vibratory removal and impact and vibratory
installation of piles.
Dates and Duration
The proposed IHA would be valid for the statutory maximum of 1 year
from the date of effectiveness, and 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 project would likely occur between April and
November 2027 and would require up to 126 days of pile removal and
installation. The window for pile removal and installation activities
is planned from May 1 through September 30 but may extend from April 1
through November 30. In-water pile removal and installation activities
may not be continuous and would only occur during daylight hours, and
typically over a 12-hour work day, up to 7 days per week.
Specific Geographic Region
The proposed activities would occur at Pier 5 of the Port of Adak,
a maritime facility owned by TAC in the city of Adak, on the northern
shoreline of Adak Island, Alaska. Adak Island is a remote island in the
central Aleutians. The pier is located at 100 Mechanic Road in the City
of Adak, Alaska. The geographical coordinates of the 2.39-acre property
are approximately 51 degrees 51' 42.57'' North, 176 degrees 38' 15.73''
West. The seafloor footprint of the pile removal and installation
activities would be within the existing footprint of Pier 5 and would
not be enlarged.
The waters around Adak Island represent a complex, high-energy
marine ecosystem characterized by deep, nutrient-rich, and cold water
that supports a high density of benthic invertebrates, marine mammals,
and seabirds. The area serves as a transitional zone between the North
Pacific Ocean and the Bering Sea, influenced by strong currents that
drive vertical mixing and create productive feeding grounds.
The coastline of Adak Island is characterized by steep slopes and
extremely deep water depths just offshore. Adak Island is subject to
strong winds and frequent storms due to its maritime climate in the
Bering Sea/North Pacific Ocean. The project area includes a large
portion of Sweeper Cover and a small portion of the adjacent Kuluk Bay.
Water depths within Sweeper Cove range from 36 to 132 (ft) (10.9 to
40.2 m). A breakwater at the entrance to Sweeper Cove creates a
protected harbor. The island is ice-free and open to navigation all
year.
[[Page 12150]]
[GRAPHIC] [TIFF OMITTED] TN12MR26.010
Detailed Description of the Specified Activity
The Port of Adak is owned by TAC and managed and operated by its
wholly owned subsidiary Aleut Enterprise, LLC. TAC is one of the 13
regional Alaska Native corporations created by the Alaska Native Claims
Settlement Act of 1971. U.S. forces built the Port of Adak and other
facilities on Adak Island during World War II. The Naval Air Facility
in Adak operationally closed in 1997, and in 2002 the U.S. Department
of the Navy and U.S. Department of the Interior entered into a land
exchange agreement with TAC that resulted in conveyance of 47,150 acres
(190.8 square kilometers) of the former Adak Naval Complex property to
TAC, including the Port of Adak.
Pier 5 was constructed by the U.S. Navy in 1980. It is a 730 ft
(222.5 m) long concrete decked pier with precast concrete panels and
concrete topping/wear surface. In 2005 and 2014, Pier 5 was evaluated
and determined to be in good condition with significant remaining life,
with the exception of the fender and piling system, which was in poor
condition.
The current fender and piling system of Pier 5 are failing, with
several portions having parted from the concrete deck. On the east side
of the pier, 12 of 56 fender pile assemblies have parted from the dock,
and on the west side of the pier, 8 of 56 fender pile assemblies have
parted from the dock. The entire timber waler system of the fenders is
severely dilapidated, and most of the timbers in the waler system are
broken or decayed (especially on the east side of the pier). The
fenders were further damaged when they were struck by barges coming to
dock at Pier 5. In December 2011, there was a barge allision incident
at the southwest corner of the pier that damaged two concrete support
piles, and in March 2018, there was another barge allision incident at
the west side of the pier (including near the previously damaged
southwest corner). Numerous timber fender system components and piles
were damaged during these incidents.
The Pier 5 Improvements Project would repair and modernize the
fender and piling system to current industry and safety standards as
well as upgrade lighting and utilities. The existing timber pile fender
system, timber wale top rail, steel egress ladders, under-deck catwalk
system, and abandoned pipelines and related infrastructure and
utilities would be removed. The current above-water footprint of Pier 5
would not be altered as it is in good condition, but the in-water
(benthic) footprint would be reduced.
Existing timber fender piles would be removed by gaining access to
the tops of piles and pulling them out. Shallow fender piles would be
extracted using a crane, when possible; however, a vibratory hammer
would be used for pile extraction if necessary. A hydraulic chainsaw
may be used to cut below the mud (sediment) line for piles that break
off during vibratory removal. The hydraulic chainsaw would be used
intermittently with a sound source level lower than vibratory pile
removal, and is not expected to have adverse impacts on marine mammals.
Under ideal conditions, extraction of piles would be accomplished
quickly, at a rate of potentially 5 to 60 piles per day. For purposes
of this analysis, TAC assumes all 385 timber piles would be removed
with a vibratory hammer.
[[Page 12151]]
Two damaged prestressed concrete piles on the southwest end of Pier
5 would be repaired, and new concrete, pile caps, bullrail, and topping
slab would be installed. These two concrete piles would be reinforced
and would not be removed. Vibratory pile driving techniques would be
used for installation of the fender piles. A modern high-energy
absorbing fender system with rubber cylindrical fenders would be
installed. The fender system would be designed around the mooring
requirements of the 58 ft (17.7 m) commercial fishing vessel fleet.
Inset egress ladders would be incorporated into the face of the fender
assemblies, and mooring cleats and bollards would be recoated.
Installation of 86 steel support piles (18- and 30-inch [45.7 and
76.2 centimeters (cm)] fender and bearing) would include vibratory pile
driving for initiation penetration, and completion with an impact
hammer. No other forms of advancement assistance (such as jetting or
overdrilling) are planned. The installation timeline would depend on
site conditions and the required embed depth of the piles. For shorter
fender piles (18 inches [45.7 cm]), potentially 1 or 15 piles may be
installed per day. TAC would minimize the use of impact pile driving
and use it only to seat the pile in its final position, or to penetrate
material that is too dense for a vibratory hammer. The total number of
piles to be installed are described in table 1.
Pile removal and installation activities would occur from floating
barges and Pier 5. The piles would be installed from the floating
barges. The barges are anticipated to be secured by multiple means with
temporary anchors and the use of barge-mounted spuds. No dredging or
trenching would be required. The pile removal and installation
activities would also include installation of a new sewer (including
upland replacement), potable water, firewater, and access control
fencing on Pier 5. The sewer and water connection points have been
coordinated with the City of Adak. All of the utilities would be routed
above ground to coordinated upland locations. All of the work would be
done in the vicinity of Pier 5 and would not extend past the southern
side of Seawall Road. Use of barges and other vessels are not expected
to result in marine mammal harassment.
For a total of up to 49 pile placement days, 86 piles would be
installed for the project and each pile would take approximately 1 day
to install. Removal of 385 timber piles with a maximum of 60 piles per
day for the project, for a total of up to 77 pile removal days.
Therefore, the estimated maximum duration for pile placement and
removal activities would be up to 126 days. The number of piles to be
removed per day depends on the condition of the piles and substrate.
Furthermore, some of the fender piles are clumped together and more
than one can be pulled at the same time. Pulling the piles will be
determined by the contractor, and likely a combination of dead pull and
vibratory pull.
Besides pile removal and installation activities, the only in-water
work would be anode installation. Anodes would be welded to the new
steel fender piles above the seafloor at approximately 15 to 22 ft (4.6
to 6.7 m) below sea level. Fender panels or foam fenders would be
bolted to the piles close to the water level. Because this activity is
not expected to appreciably increase in-water noise levels; it is not
expected to result in harassment of marine mammals. Similarly, top-side
work such as upgrade lighting and utilities and adding new concrete and
pile caps to existing concrete piles is not expected to result in
marine mammal harassment. Therefore, TAC did not request, and NMFS is
not proposing to authorize, take from anode installation or above-water
activities.
Table 1--Summary of Pier 5 Improvements Project Pile Removal and Installations
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Vibratory
Impact hammer hammer Estimated
Pile type and size Total number Minimum Maximum number strikes per duration per number of days
of piles number per day per day pile 1 2 pile \2\ \3\
(minutes)
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Piles to be Installed
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30-inch Steel Fender Pile............................... 6 1 3 600 30 to 45 6
30-inch Steel Bearing Pile.............................. 1 1 1 1,200 30 to 45 3
18-inch Steel Fender Pile............................... 79 2 15 300 30 to 45 6 to 40
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Piles to be Removed
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12-inch Timber Pile \4\................................. 385 5 60 NA 10 to 20 7 to 77
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\1\ Estimated based on vibrating piles to a depth of 15 ft (4.6 m) below the mudline, then impact hammer driving to final tip elevation with 30 strikes
per foot and a strike rate of one blow every 2 seconds.
\2\ The total estimated time to install the fender piles is 2 to 3 hours. The actual time driving with the vibratory hammer will be less, approximately
30 to 45 minutes each. Installation of steel support (both fender and bearing) piles will likely be driven by first using vibratory driving to start
the pile for the upper 10 to 20 ft (3 to 6.1 m) of embedment, and final driving will be accomplished using a diesel impact hammer.
\3\ TAC estimates pile removal and installation activities could occur for up to 126 days, depending on the number of piles removed and installed per
day.
\4\ Timber piles will be extracted with a crane and/or vibratory hammer. For piles that cannot be pulled statically, a vibratory hammer may be used to
vibrate the piles during extraction.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting sections).
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
[[Page 12152]]
these species (e.g., physical and behavioral descriptions) may be found
on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 2 lists all species or stocks for which take is expected and
proposed to be authorized for this activity, and summarizes information
related to the population or stock, including regulatory status under
the MMPA and Endangered Species Act (ESA) and potential biological
removal (PBR), where known. PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no serious injury or mortality is anticipated or proposed
to be authorized here, PBR and annual serious injury and mortality 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' Alaska Marine Mammal Stock Assessments (e.g., Young et al.,
2025). All values presented in table 2 are the most recent available at
the time of publication, including from the draft 2024 SARs, and are
available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
Table 2--Species Likely Impacted by the Specified Activities
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Stock abundance
(CV, Nmin, most Potential Total annual
Common name Scientific name Stock ESA/MMPA status; recent abundance biological mortality/
strategic (Yes/No) \1\ survey) \2\ removal serious injury
\3\
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Order Artiodactyla--Infraorder Cetacea--Mysticeti (Baleen Whales)
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Family Balaenopteridae:
Humpback Whale.............. Megaptera Hawai[revaps]i..... -, -, N E, D, Y 11,278 (0.56, 127 27.09
novaeangliae. 7,265, 2002-2020).
Mexico--North T, D, Y N/A (N/A, N/A, UND 0.57
Pacific. 2006) \ 4\.
Western North ........................ 1,084, (0.088, 3.4 5.82
Pacific. 1,007, 2004-2006).
Minke Whale................. Balaenoptera Alaska............. -, -, N N/A (N/A, N/A, N/ N/A 0
acutorostrata. A) \5\.
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Odontoceti (Toothed Whales, Dolphins, and Porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae (Dolphins):
Killer Whale................ Orcinus orca....... Eastern North -, -, N 1,920 (N/A, 1,920, 19 1.3
Pacific Alaska 2005-2019).
Resident.
Eastern North -, -, N 587 (N/A, 587, 5.9 0.8
Pacific Gulf of 2012).
Alaska, Aleutian
Islands, and
Bering Sea
Transient.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Pinnipedia (Seals and Sea Lions)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (Eared Seals
and Sea Lions):
Steller Sea Lion............ Eumetopias jubatus. Western............ E, D, Y 49,837 (N/A, 439 267
73,211, 2021-
2022).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (Earless Seals):
Harbor Seal................. Phoca vitulina..... Aleutian Islands... -, -, N 5,588 (N/A, 5,366, 97 90
2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: <a href="https://www.nmfs.noaa.gov/pr/sars/">https://www.nmfs.noaa.gov/pr/sars/</a>. CV is coefficient of variation; Nmin is the minimum
estimate of stock abundance.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, vessel strike, Native subsistence mortality). Annual M/SI often cannot be determined precisely and is in some cases presented as
a minimum value or range.
\4\ Abundance estimates are based upon data collected more than 8 years ago and therefore current estimates are considered unknown.
\5\ Reliable population estimates are not available for this stock. Please see Friday et al. (2013) and Zerbini et al. (2006) for additional information
on numbers for minke whales in Alaska.
As indicated above, all five species (with eight managed stocks) in
table 2 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. All species of marine
mammals that could potentially occur in the proposed project area are
included in table 3-1 of the IHA application. While blue whale
(Balaenoptera musculus), fin whale (Balaenoptera physalus), Eastern
North Pacific and Western North Pacific gray whale (Eschrichtius
robustus), North Pacific right whale (Eubalaena japonica), sei whale
(Balaenoptera borealis), sperm whale (Physeter macrocephalus), Baird's
beaked whale (Berardius bairdii), Cuvier's beaked whale (Ziphius
cavirostris), Sato's beaked whale (Berardius minimus), Stejneger's
beaked whale (Mesoplodon stejnegeri), Pacific white-sided dolphin
(Lagenorhynchus obliquidens), Dall's porpoise (Phocoenoides dalli),
harbor porpoise (Phocoena phocoena), Northern fur seal (Callorhinus
ursinus), Northern elephant seal (Mirounga
[[Page 12153]]
angustirostris), and ribbon seal (Histriophoca fasciata) could occur in
the area, the temporal and/or spatial occurrence of these species is
such that take is not expected to occur. These species all have
extremely low abundance and most are observed in areas outside of the
project area due to it being nearshore and its inlet geography;
therefore, they are not discussed further beyond the explanation
provided here.
In addition, northern sea otter (Enhydra lutris kenyoni) may be
found in the central Aleutian Islands. However, this species is managed
by the U.S. Fish and Wildlife Service and is not considered further in
this document.
Humpback Whale
On September 8, 2016, NMFS divided the once single population into
14 distinct population segments (DPS) under the ESA, removed the
species-level listing as endangered, and, in its place, listed four
DPSs as endangered and one DPS as threatened (81 FR 62259, September 8,
2016). The remaining nine DPSs were not listed. There are four DPSs in
the North Pacific Ocean, including the Western North Pacific and
Central America, which are listed as endangered, Mexico, which is
listed as threatened, and Hawai[revaps]i, which is not listed.
The 2022 Alaska and Pacific SARs described a revised stock
structure for humpback whales which modifies the previous stocks
designated under the MMPA to align more closely with the ESA-designated
DPSs (Caretta et al., 2023; Young et al., 2023). Specifically, the
three previous North Pacific humpback whale stocks (Central and Western
North Pacific stocks and a California/Oregon/Washington [CA/OR/WA]
stock) were replaced by five stocks, largely corresponding with the
ESA-designated DPSs. These include the Western North Pacific and
Hawai[revaps]i stocks and a Central America/Southern Mexico-CA/OR/WA
stock (which corresponds with the Central America DPS). The remaining
two stocks, corresponding with the Mexico DPS, are the Mainland Mexico-
CA/OR/WA and Mexico-North Pacific stocks (Caretta et al., 2023; Young
et al., 2023). The former stock is expected to occur along the west
coast from California to southern British Columbia, while the latter
stock may occur across the Pacific, from northern British Columbia
through the Gulf of Alaska and Aleutian Islands/Bering Sea region to
Russia.
The Hawai[revaps]i stock consists of one demographically
independent population (DIP)--Hawai[revaps]i-Southeast Alaska/Northern
British Columbia DIP and one unit--Hawai[revaps]i-North Pacific unit,
which may or may not be composed of multiple DIPs (Wade et al., 2021).
The DIP and unit are managed as a single stock at this time, due to the
lack of data available to separately assess them and lack of compelling
conservation benefit to managing them separately (NMFS, 2023; NMFS,
2019; NMFS, 2022b). The DIP is delineated based on two strong lines of
evidence: genetics and movement data (Wade et al., 2021). Whales in the
Hawai[revaps]i-Southeast Alaska/Northern British Columbia DIP winter
off Hawai[revaps]i and largely summer in Southeast Alaska and Northern
British Columbia (Wade et al., 2021). The group of whales that migrate
from Russia, western Alaska (Bering Sea and Aleutian Islands), and
central Alaska (Gulf of Alaska excluding Southeast Alaska) to
Hawai[revaps]i have been delineated as the Hawai[revaps]i-North Pacific
unit (Wade et al., 2021). There are a small number of whales that
migrate between Hawai[revaps]i and southern British Columbia/
Washington, but current data and analyses do not provide a clear
understanding of which unit these whales belong to (Wade et al., 2021;
Caretta et al., 2023; Young et al., 2023).
The Mexico-North Pacific unit is likely composed of multiple DIPs,
based on movement data (Martien et al., 2021; Wade, 2021; Wade et al.,
2021). However, because currently available data and analyses are not
sufficient to delineate or assess DIPs within the unit, it was
designated as a single stock (NMFS, 2023a; NMFS, 2019; NMFS, 2022c).
Whales in this stock winter off Mexico and the Revillagigedo
Archipelago and summer primarily in Alaska waters (Martien et al.,
2021; Carretta et al., 2023; Young et al., 2023).
The Western North Pacific stock consists of two units--the
Philippines/Okinawa-North Pacific unit and the Marianas/Ogasawara-North
Pacific unit. The units are managed as a single stock at this time, due
to a lack of data. Recognition of these units is based on movements and
genetic data (Oleson et al., 2022). Whales in the Philippines/Okinawa-
North Pacific unit winter near the Philippines and in the Ryukyu
Archipelago and migrate to summer feeding areas primarily off the
Russian mainland (Oleson et al., 2022). Whales that winter off the
Mariana Archipelago, Ogasawara, and other areas not yet identified and
then migrate to summer feeding areas off the Commander Islands, and to
the Bering Sea and Aleutian Islands comprise the Marianas/Ogasawara-
North Pacific unit.
Humpback whales that occur in the project area are predominantly
members of the Hawai'i stock, which corresponds to the Hawai[revaps]i
DPS (91 percent probability in the Aleutian Islands), and is not listed
under the ESA. However, members of the Mexico North Pacific stock,
which include the Mexico DPS and is listed as threatened under the ESA,
have a small potential to occur in the project location (7 percent
probability in the Aleutian Islands), and the Western North Pacific
stock, which corresponds to the Western North Pacific DPS and is listed
as endangered under the ESA, have an even smaller potential to occur in
the project location (2 percent probability in the Aleutian Islands).
Humpback whales migrate to the North Pacific Ocean, including the
Aleutian Islands, to feed after months of fasting in equatorial
breeding grounds. Humpback whales generally travel alone or in small
groups that persist for only a few hours. Groups may stay together for
longer in the summer in order to feed cooperatively. The Alaska
Department of Fish and Game reports that humpback whales occur in the
Aleutian Islands in the spring, summer, and fall during their
migration. Humpback whales are regularly observed around Adak Island
during the summer and early fall when prey availability is highest.
They are typically seen in small groups or as solitary individuals.
Local reports indicate that humpback whales are occasionally seen in
Kuluk Bay near the Port of Adak.
Minke Whale
Minke whales occur in polar, temperate, and tropical waters
worldwide in a range extending from the ice edge in the Arctic during
the summer to near the equator during winter. However, they are known
to prefer temperate to boreal waters due to the abundance of prey
(Guerrero, 2008b). When comparing distribution and abundance in the
years 2002, 2008, and 2010, it was found that that minke whales were
scattered throughout all oceanographic domains: coastal, middle shelf,
and outer shelf/slope (Muto et al., 2021). The minke whale mostly
migrates seasonally and can travel long distances; although, some minke
whale individuals and stocks have resident home ranges and are not
highly migratory (Guerrero, 2008b). The Alaska stock of minke whales
are migratory and are common in the waters of the Bering Sea, Gulf of
Alaska, and Southeast Alaska in the spring and summer (NMFS, 2023c).
The distribution of minke whales vary according to age, sex, and
reproductive status. Older mature males are commonly found in small
social groups
[[Page 12154]]
around the ice edge of polar regions during the summer feeding season.
Comparatively, adult females will migrate farther into the higher
latitudes but generally remain in coastal waters. Immature minke whales
tend to be solitary and stay in lower latitudes during the summer
(Guerrero, 2008b). Although the minke whale tends to be solitary or in
groups of 2 to 3 individuals, they can congregate into larger groups
containing up to 400 individuals at the higher latitude foraging areas
(Clark, 2008a; Guerrero 2008b; NOAA, 2021). During surveys in Alaska,
minke whales are predominately observed alone (Wade et al., 2003;
Waite, 2003). Breeding season typically occurs from December to March,
but in some regions minke whales breed year-round. When migrating north
in spring and summer, they will travel along in coastal waters, whereas
in fall and winter, they move farther offshore (NMFS, 2023c). There are
no known observations of minke whales in the project area.
Killer Whale
Killer whales occur in every ocean in the world and are the most
widely distributed of all cetaceans. Along the west coast of North
America, killer whales occur along the entire Alaska coast (Braham and
Dahlheim, 1982). This proposed IHA considers only the Eastern North
Pacific Alaska Resident stock (Alaska Resident stock), and the Eastern
North Pacific Gulf of Alaska, Aleutian Islands, and Bering Sea
Transient stock because all other killer whale stocks occur outside the
geographic area under consideration (Muto et al., 2021; Young et al.
2023).
There are three distinct ecotypes, or forms, of killer whales
recognized: Resident, Transient, and Offshore. The three ecotypes
differ morphologically, ecologically, behaviorally, and genetically.
Spatial distribution has been shown to vary among the different
ecotypes, with resident and, to a lesser extent, transient killer
whales more commonly observed along the continental shelf, and offshore
killer whales more commonly observed in pelagic waters (Rice et al.,
2021).
When comparing movement, residents tend to have more predictable
movements and the smallest home ranges and they return annually,
whereas transients are less predictable due to their larger home ranges
and quick transits through local areas. Offshore ecotypes have the
largest home ranges that are generally farther offshore compared to the
other two ecotypes (Zimmerman and Small, 2008). Resident killer whales
live in large, stable groups ranging normally from 5 to 50 individuals
and up to 100 or more. They feed only on fish, especially Pacific
salmon. Transient killer whales, on the other hand, hunt marine
mammals, like pinnipeds and porpoises, in smaller groups of 10
individuals or less (Forney and Wade, 2006).
Killer whales have been observed in the Aleutian Islands and into
the Bering Sea year-round, most commonly during the summer Chinook
salmon run (May through July) when the project would occur. However,
local reports indicate that killer whales are infrequently seen
transiting through the area near Adak Island.
Steller Sea Lion
Steller sea lions in the project area are anticipated to be from
the Western stock, which includes all Steller sea lions originating
from rookeries west of Cape Suckling (144[deg] West longitude). The
centers of abundance and distribution for Western DPS Steller sea lions
are located in the Gulf of Alaska and Aleutian Islands. At sea, Steller
sea lions commonly occur near the 656-ft (200-m) depth contour but have
been found from nearshore to well beyond the continental shelf
(Kajimura and Loughlin, 1988). Steller sea lions move offshore to
pelagic waters for feeding excursions.
There are major (i.e., haulouts supporting greater than 200
individuals) Steller sea lion haulouts and rookeries throughout the
Aleutian Islands and along the southern end of southwest Alaska. The
rookery, Lake Point, is located at the tip of the Yakak Peninsula on
southern Adak, on the opposite side of the island and approximately
35.4 miles (57 kilometers [km]) from Pier 5. The three major haulouts
are Cape Yakak on Adak (near Lake Point on the Yakak Peninsula, about
36.7 miles (59 km) from Pier 5 and on the opposite side of the island)
and Ragged Point on Kagalaska (on the side of the island facing away
from the project site and about 27.3 miles [44 km] away). Five other
haulouts in the area, include Argonne Point, Cape Kagigikak, Crone
Island, Cape Moffet, and Head Rock on Adak Island, and Kagalaska on
Kagalaska Island, have been lesser used in recent years (Sweeney et
al., 2023). These sites are used year-round, with increased activity
during the breeding season (mid-May through mid-July). Steller sea
lions are often seen foraging near fish processing facilities, marine
outfalls, and natural prey aggregations, especially during pollock and
Atka mackerel seasons. Steller sea lions are occasionally seen foraging
during small, seasonal (mid-June through September), steady runs of
coho salmon (Oncorhnchus kisutch), pink salmon (Oncorhynchus
gorbuscha), and Dolly Varden (Salvelinus malma) at the mouth of creeks
and streams at the west end of Sweeper Cover (approximately 0.65 miles
west of Pier 5).
Harbor Seal
Harbor seals inhabit coastal and estuarine waters off Alaska. They
haul out on rocks, reefs, beaches, and drifting glacial ice. They are
generally non-migratory, with local movements associated with such
factors as tides, weather, season, food availability, and reproduction
(Muto et al., 2021). They are opportunistic feeders and often adjust
their distribution to take advantage of locally and seasonally abundant
prey (Womble et al., 2010; Allen and Angliss, 2015). Although they tend
to be solitary when in the water, they can form groups of about 30 or
less individuals of both sexes and all ages when hauling out. Harbor
seals haul out to rest periodically, give birth or nurse.
Harbor seals in the project area are recognized as part of the
Aleutian Island stock, occurring along the entire Aleutian island chain
from Attu Island to Ugamak Island. Pupping season in the Aleutian
Islands occurs between mid-June to mid-July (Sease, 1992). Harbor seals
are regularly observed year-round around Adak Island, particularly in
Clam Lagoon. Clam Lagoon is a shallow, protected body of water on the
northern coast of Adak Island. Clam Lagoon, which is about 6.2 miles
(10 km) north of the Port of Adak, is the closest known haulout to the
project area. A 2014 study tagged 15 harbor seals in Clam Lagoon and
tracked their dive behavior, haul-out patterns, and movement, which
determined that the area is a key habitat for the species (NMFS 2017).
There have been local anectodal observations of the daily occurrence of
harbor seals in the project area (Matthew Holsinger personal
communication with Andrew Fisher on May 29, 2025).
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
[[Page 12155]]
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.).
Baleen whale hearing range is based on hearing measurements through
auditory evoked potential (AEP) tests. NMFS is aware that the National
Marine Mammal Foundation successfully collected preliminary hearing
data on minke whales in Norway (Houser et al. 2024). However, results
from both field seasons have yet to be published and therefore those
data are not yet considered in this analysis. Subsequently, NMFS (2018)
described generalized hearing ranges for these marine mammal hearing
groups. Generalized hearing ranges were chosen based on the
approximately 65-decibel (dB) threshold from the normalized composite
audiograms, with the exception for lower limits for low-frequency
cetaceans where the lower bound was deemed to be biologically
implausible and the lower bound from Southall et al. (2007) retained.
In October 2024, NMFS published its 2024 Updated Technical Guidance,
which includes updated thresholds and weighting functions to inform
auditory injury (AUD INJ) estimates and 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 Hz to 35 kHz.
whales).
High-frequency (HF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
Very High-frequency (VHF) cetaceans 200 Hz to 165 kHz.
(true porpoises, Kogia, river
dolphins, Cephalorhynchid,
Lagenorhynchus cruciger, and L.
australis).
Phocid pinnipeds (PW) (underwater) 40 Hz to 90 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 68 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65-dB threshold from composite
audiogram, previous analysis in NMFS (2018), and/or data from Southall
et al. (2007, 2019). Additionally, animals are able to detect very
loud sounds above and below that ``generalized'' hearing range.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take of Marine Mammals section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take of Marine Mammals section, and the Proposed Mitigation
section, to draw conclusions regarding the likely impacts of these
activities on the reproductive success or survivorship of individuals
and whether those impacts are reasonably expected to, or reasonably
likely to, adversely affect the species or stock through effects on
annual rates of recruitment or survival.
NMFS has summarized a brief technical description of the physics of
sound and relevant measurement metrics (i.e., root mean square [RMS],
Peak, and sound exposure level [SEL]) (NMFS, 2024), available online at
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>. We refer readers to this
document for definitions of the measurement terms and metrics used
herein.
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
In-water pile removal and installation activities associated with
the project would include impact pile driving and vibratory pile
driving and removal. The sounds produced by these activities fall into
one of two general sound types: Impulsive and non-impulsive. Impulsive
sounds (e.g., explosions, gunshots, sonic booms, impact pile driving)
are typically transient, brief (less than 1 second), broadband, and
consist of high peak sound pressure with rapid rise time and rapid
decay (American National Standards Institute [ANSI], 1986; National
Institute of Occupational Safety and Health [NIOSH], 1998; NMFS, 2018).
Non-impulsive sounds (e.g., aircraft, machinery operations such as
drilling or dredging, vibratory pile driving, and active sonar systems)
can be broadband, narrowband or tonal, brief or prolonged (continuous
or intermittent), and typically do not have the high peak sound
pressure with rapid rise/decay time that impulsive sounds do (ANSI,
1995; NIOSH, 1998; NMFS, 2018). The distinction between these two sound
types is important because they have differing potential to cause
physical effects, particularly with regard to hearing (e.g., Ward 1997
in Southall et al., 2007).
Two types of hammers would be used on this project: impact and
vibratory. Impact hammers 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 characterized by rapid rise times and
high peak levels, a potentially injurious combination (Hastings and
Popper, 2005). Vibratory hammers install piles by vibrating them and
allowing the weight of the hammer to push them into the sediment.
Vibratory hammers produce significantly less sound than impact hammers.
Peak Sound Pressure Levels (SPLs) may be 180 dB or greater but are
generally 10 to 20 dB lower than SPLs generated during impact pile
driving of the same-sized pile (Oestman et al., 2009). Rise time is
slower, reducing the probability and severity of injury, and sound
energy is distributed over a greater amount of time (Nedwell and
Edwards, 2002; Carlson et al., 2005).
Potential Effects of Underwater Sound on Marine Mammals
The introduction of anthropogenic noise into the aquatic
environment from
[[Page 12156]]
pile driving and removal equipment is the primary means by which marine
mammals may be harassed from TAC's specified activities. In general,
animals exposed to natural or anthropogenic sound may experience
behavioral, physiological, and/or physical effects, ranging in
magnitude from none to severe (Southall et al., 2007). Generally,
exposure to pile driving and removal noise has the potential to result
in behavioral reactions (e.g., avoidance, temporary cessation of
foraging and vocalizing, changes in dive behavior) and, in limited
cases, auditory threshold shifts. Exposure to anthropogenic noise can
also lead to non-observable physiological responses such as an increase
in stress hormones. Additional noise in a marine mammal's habitat can
mask acoustic cues used by marine mammals to carry out daily functions
such as communication and predator and prey detection. The effects of
pile driving and removal noise on marine mammals are dependent on
several factors, including, but not limited to, sound type (e.g.,
impulsive vs. non-impulsive), the species, age and sex class (e.g.,
adult male vs. mother with calf), duration of exposure, the distance
between the pile and the animal, received levels, behavior at time of
exposure, and previous history with exposure (Wartzok et al., 2003;
Southall et al., 2007). Here we discuss physical auditory effects
(threshold shifts) followed by behavioral effects and potential impacts
on habitat.
Hearing Threshold Shifts
NMFS defines a noise-induced threshold shift (TS) as a change,
usually an increase, in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). 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), likelihood an individual would be exposed for a long
enough duration or to a high enough level to induce a TS, the magnitude
of the TS, time to recovery (seconds to minutes or hours to days), the
frequency range of the exposure (i.e., spectral content), the hearing
and vocalization frequency range of the exposed species relative to the
signal's frequency spectrum (i.e., how animal uses sound within the
frequency band of the signal; e.g., Kastelein et al., 2014), and the
overlap between the animal and the source (e.g., spatial, temporal, and
spectral).
Auditory Injury--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 a permanent threshold shift (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 AUD INJ onset (Ward et al., 1958; Ward et
al., 1959; Ward, 1960; Kryter et al., 1966; Miller, 1974; Henderson et
al., 2008). However, a variety of terrestrial and marine mammal studies
(see Ward et al., 1958; Ward et al., 1959; Ward, 1960; Miller et al.,
1963; Kryter et al., 1966; Finneran 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 (Phoca
vitulina) (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 temporary threshold shift
(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.
Temporary Threshold Shift--A temporary, fully reversible increase
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS, 2018). Based on data from cetacean TTS measurements
(Southall et al., 2007), 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 (Schlundt et
al., 2000; Finneran et al., 2000; Finneran et al., 2002). As described
in Finneran (2016), marine mammal studies have shown the amount of TTS
increases with cumulative sound exposure level (SEL<INF>cum</INF>) in
an accelerating fashion: At low exposures with lower SEL<INF>cum,</INF>
the amount of TTS is typically small and the growth curves have shallow
slopes. At exposures with higher SEL<INF>cum,</INF> the growth curves
become steeper and approach linear relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in Masking,
below). For example, a marine mammal may be able to readily compensate
for a brief, relatively small amount of TTS in a non-critical frequency
range that takes place during a time when the animal is traveling
through the open ocean, where ambient noise is lower and there are not
as many competing sounds present. Alternatively, a larger amount and
longer duration of TTS sustained during time when communication is
critical for successful mother/calf interactions could have more
serious impacts. We note that reduced hearing sensitivity as a simple
function of aging has been observed in marine mammals, as well as
humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis) and five species of pinnipeds exposed to a
[[Page 12157]]
limited number of sound sources (i.e., mostly tones and octave-band
noise) in laboratory settings (Finneran, 2015). TTS was not observed in
trained spotted (Phoca largha) and ringed (Pusa hispida) seals exposed
to impulsive noise at levels matching previous predictions of TTS onset
(Reichmuth et al., 2016). In general, harbor seals and harbor porpoises
have a lower TTS onset than other measured pinniped or cetacean species
(Finneran, 2015). Additionally, the existing marine mammal TTS data
come from a limited number of individuals within these species. No data
are available on noise-induced hearing loss for mysticetes. For
summaries of data on TTS in marine mammals or for further discussion of
TTS onset thresholds, please see Southall et al. (2007), Finneran and
Jenkins (2012), Finneran (2015), and table 5 in NMFS (2018).
Activities for this project include impact and vibratory pile
driving as well as vibratory pile removal activities. There would
likely be pauses in activities producing the sound during each day.
Given these pauses and the fact that many marine mammals are likely
moving through the project area and not remaining for extended periods
of time, the potential for threshold shift declines.
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
avoidance 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 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.
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; National
Research Council [NRC], 2005).
The following subsections provide examples of behavioral responses
that provide an idea of the variability in behavioral responses that
would be expected given the differential sensitivities of marine mammal
species to sound and the wide range of potential acoustic sources to
which a marine mammal may be exposed. Behavioral responses that could
occur for a given sound exposure should be determined from the
literature that is available for each species, or extrapolated from
closely related species when no information exists, along with
contextual factors. 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. There are broad categories of potential
response, which we describe in greater detail here, that include
alteration of dive behavior, alteration of foraging behavior, effects
to respiration, interference with or alteration of vocalization,
avoidance, and flight.
Pinnipeds may increase their haul out time, possibly to avoid in-
water disturbance (Thorson and Reyff, 2006). Behavioral reactions can
vary not only among individuals but also within an individual,
depending on previous experience with a sound source, context, and
numerous other factors (Ellison et al., 2012), and can vary depending
on characteristics associated with the sound source (e.g., whether it
is moving or stationary, number of sources, distance from the source).
In general, pinnipeds seem more tolerant of, or at least habituate more
quickly to, potentially disturbing underwater sound than do cetaceans,
and generally seem to be less responsive to exposure to industrial
sound than most cetaceans.
Alteration of Dive Behavior--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., 2013). Seals
exposed to non-impulsive sources with a received SPL within the range
of calculated exposures (142-193 dB referenced to 1 micropascal [re 1
[mu]Pa]), have been shown to change their behavior by modifying diving
activity and avoidance of the sound source (G[ouml]tz and Janik, 2010;
Kvadsheim et al., 2010). Variations in dive behavior may reflect
interruptions in biologically significant activities (e.g., foraging)
or they may be of little biological significance. The impact of an
alteration to dive behavior resulting from an acoustic exposure depends
on what the animal is doing at the time of the exposure and the type
and magnitude of the response.
Alteration of Feeding Behavior--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,
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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;
Melc[oacute]n et al., 2012). In addition, behavioral state of the
animal plays a role in the type and severity of a behavioral response,
such as disruption to foraging (e.g., Silve et al., 2016; Wensveen et
al., 2017). An evaluation of whether foraging disruptions would be
likely to incur fitness consequences considers temporal and spatial
scale of the activity in the context of the available foraging habitat
and, in more severe cases may necessitate consideration of information
on or estimates of the energetic requirements of the affected
individuals and the relationship between prey availability, foraging
effort and success, and the life history stage of the animal. Goldbogen
et al. (2013) indicate that disruption of feeding and displacement
could impact individual fitness and health. However, for this to be
true, we would have to assume that an individual could not compensate
for this lost feeding opportunity by either immediately feeding at
another location, by feeding shortly after cessation of acoustic
exposure, or by feeding at a later time. There is no indication this is
the case here, particularly since prey would likely still be available
in the environment in most cases following the cessation of acoustic
exposure.
Respiration--Respiration naturally varies with different behaviors,
and variations in respiration 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. Studies with captive harbor porpoises showed increased
respiration rates upon introduction of acoustic alarms (Kastelein et
al., 2001; Kastelein et al., 2006a) and emissions for underwater data
transmission (Kastelein et al., 2005). Various studies also have shown
that species and signal characteristics are important factors in
whether respiration rates are unaffected or change, again highlighting
the importance in 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., 2005;
Kastelein et al., 2006; Kastelein et al., 2018; Gailey et al., 2007;
Isojunno et al., 2018).
Vocalization--Marine mammals vocalize for different purposes and
across multiple modes, such as whistling, echolocation click
production, calling, and singing. Changes in vocalization behavior in
response to anthropogenic noise can occur for any of these modes and
may result from a need to compete with an increase in background noise
or may reflect increased vigilance or a startle response. For example,
in the presence of potentially masking signals, humpback whales and
killer whales have been observed to increase the length of their songs
(Miller et al., 2000; Fristrup et al., 2003; Foote et al., 2004), while
right whales 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; Rolland et al., 2012). Killer
whales off the northwestern coast of the United States have been
observed to increase the duration of primary calls once a threshold in
observing vessel density (e.g., whale watching) was reached, which has
been suggested as a response to increased masking noise produced by the
vessels (Foote et al., 2004; NOAA, 2014). In some cases, however,
animals may cease or alter sound production in response to underwater
sound (e.g., Bowles et al., 1994; Castellote et al., 2012; Cerchio et
al., 2014). Studies also demonstrate that even low levels of noise
received far from the noise source can induce changes in vocalization
and/or behavioral responses (Blackwell et al., 2013; Blackwell et al.,
2015).
Avoidance--Avoidance is the displacement of an individual from an
area or migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). Avoidance is qualitatively
different from the flight response, but also differs in the magnitude
of the response (i.e., directed movement, rate of travel, etc.). Often
avoidance is temporary, and animals return to the area once the noise
has ceased. Acute avoidance responses have been observed in captive
porpoises and pinnipeds exposed to a number of different sound sources
(Kastelein et al., 2001; Finneran et al., 2003; Kastelein et al.,
2006a; Kastelein et al., 2006b; Kastelein et al., 2015b; Kastelein et
al., 2015c; Kastelein et al., 2018). Short-term avoidance of seismic
surveys, low frequency emissions, and acoustic deterrents have also
been noted in wild populations of odontocetes (Bowles et al., 1994;
Goold, 1996; Goold and Fish, 1998; Morton and Symonds, 2002; Hiley et
al., 2021) and to some extent in mysticetes (Malme et al., 1984;
McCauley et al., 2000; Gailey et al., 2007). Longer-term displacement
is possible, however, which may lead to changes in abundance or
distribution patterns of the affected species in the affected region if
habituation to the presence of the sound does not occur (e.g.,
Blackwell et al., 2004; Bejder et al., 2006; Teilmann et al., 2006).
Forney et al. (2017) described the potential effects of noise on
marine mammal populations with high site fidelity, including
displacement and auditory masking. In cases of Western North Pacific
DPS/stock of gray whales and Cuvier's/goose-beaked whales (Ziphius
cavirostris), anthropogenic effects in areas where they are resident or
exhibit site fidelity could cause severe biological consequences, in
part because displacement may adversely affect foraging rates,
reproduction, or health, while an overriding instinct to remain in the
area could lead to more severe acute effects. Avoidance of overlap
between disturbing noise and areas and/or times of particular
importance for sensitive species may be critical to avoiding
population-level impacts because (particularly for animals with high
site fidelity) there may be a strong motivation to remain in the area
despite negative impacts.
Flight Response--A flight response is a dramatic change in normal
movement to a directed and rapid movement away from the perceived
location of a sound source. The flight response differs from other
avoidance responses in the intensity of the response (e.g., directed
movement, rate of travel). Relatively little information on flight
responses of marine mammals to anthropogenic signals exist, although
observations of flight responses to the presence of predators have
occurred (Connor and Heithaus, 1996). 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 (Evans and England, 2001). There are limited data on
flight response for marine mammals in water; however, there are
examples of this response in species on land. For instance, the
probability of flight responses in Dall's sheep (Ovis dalli dalli)
(Frid, 2003), hauled out ringed seals (Phoca hispida) (Born et al.,
1999), Pacific brant (Branta bernicla nigricans), and Canada geese (B.
canadensis) increased as a helicopter or fixed-wing aircraft more
directly approached groups of these animals (Ward et al., 1999).
However, it should be noted that
[[Page 12159]]
response to a perceived predator does not necessarily invoke flight
(Ford and Reeves, 2008), and whether individuals are solitary or in
groups may influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been observed in marine mammals, but studies
involving fish and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates and efficiency (e.g.,
Beauchamp and Livoreil, 1997; Fritz et al., 2002; Purser and Radford,
2011). In addition, chronic disturbance can cause population declines
through reduction of fitness (e.g., decline in body condition) and
subsequent reduction in reproductive success, survival, or both (e.g.,
Harrington and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998).
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than 1 day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive behavioral reactions and multi-day anthropogenic
activities. For example, just because an activity lasts for multiple
days does not necessarily mean that individual animals are either
exposed to activity-related stressors for multiple days or, further,
exposed in a manner resulting in sustained multi-day substantive
behavioral responses.
To assess the strength of behavioral changes and responses to
external sounds and SPLs associated with changes in behavior, Southall
et al. (2007) developed and utilized a severity scale, which is a 10-
point scale ranging from no effect (labeled 0), effects not likely to
influence vital rates (low; labeled from one to three), effects that
could affect vital rates (moderate; labeled from 4 to 6), to effects
that were thought likely to influence vital rates (high; labeled from 7
to 9). Southall et al. (2021) updated the severity scale by integrating
behavioral context (i.e., survival, reproduction, and foraging) into
severity assessment. For non-impulsive sounds (i.e., similar to the
sources used during the proposed action), data suggest that exposures
of pinnipeds to sources between 90 and 140 dB re 1 [mu]Pa do not elicit
strong behavioral responses; no data were available for exposures at
higher received levels for Southall et al. (2007) to include in the
severity scale analysis. Reactions of harbor seals were the only
available data for which the responses could be ranked on the severity
scale. For reactions that were recorded, the majority (17 of 18
individuals/groups) were ranked on the severity scale as a 4 (defined
as moderate change in movement, brief shift in group distribution, or
moderate change in vocal behavior) or lower. The remaining response was
ranked as a six (defined as minor or moderate avoidance of the sound
source).
Habituation--Habituation can occur when an animal's response to a
stimulus wanes with repeated exposure, usually in the absence of
unpleasant associated events (Wartzok et al., 2003). Animals are most
likely to habituate to sounds that are predictable and unvarying. It is
important to note that habituation is appropriately considered as a
``progressive reduction in response to stimuli that are perceived as
neither aversive nor beneficial,'' rather than as, more generally,
moderation in response to human disturbance (Bejder et al., 2009). The
opposite process is sensitization, when an unpleasant experience leads
to subsequent responses, often in the form of avoidance, at a lower
level of exposure. As noted, behavioral state may affect the type of
response. For example, animals that are resting may show greater
behavioral change in response to disturbing sound levels than animals
that are highly motivated to remain in an area for feeding (Richardson
et al., 1995; NRC, 2003; Wartzok et al., 2003). 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 impulsive sound sources (typically seismic airguns or acoustic
harassment devices) have been varied but often consist of avoidance
behavior or other behavioral changes suggesting discomfort (Morton and
Symonds, 2002; Richardson et al., 1995; Nowacek et al., 2007).
Stress Responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker, 2000;
Romano et al., 2002b) and, more rarely, studied in wild populations
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found
that noise reduction from reduced ship traffic in the Bay of Fundy was
associated with decreased stress in North Atlantic right whales. These
and
[[Page 12160]]
other studies lead to a reasonable expectation that some marine mammals
will experience physiological stress responses upon exposure to
acoustic stressors and that it is possible that some of these would be
classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2003), however
distress is an unlikely result of these projects based on observations
of marine mammals during previous, similar projects.
Auditory Masking--Sound can disrupt behavior through masking, or
interfering 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). Masking
occurs when the receipt of a sound is interfered with by another
coincident sound at similar frequencies and at similar or higher
intensity, and may occur whether the sound is natural (e.g., snapping
shrimp, wind, waves, precipitation) or anthropogenic (e.g., pile
driving, shipping, sonar, seismic exploration) in origin. The ability
of a noise source to mask biologically important sounds depends on the
characteristics of both the noise source and the signal of interest
(e.g., signal-to-noise ratio, temporal variability, direction), in
relation to each other and to an animal's hearing abilities (e.g.,
sensitivity, frequency range, critical ratios, frequency
discrimination, directional discrimination, age or TTS hearing loss),
and existing ambient noise and propagation conditions. Masking of
natural sounds can result when human activities produce high levels of
background sound at frequencies important to marine mammals.
Conversely, if the background level of underwater sound is high (e.g.,
on a day with strong wind and high waves), an anthropogenic sound
source would not be detectable as far away as would be possible under
quieter conditions and would itself be masked.
Airborne Acoustic Effects--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving
and removal that have the potential to cause behavioral harassment,
depending on their distance from pile driving activities. Cetaceans are
not expected to be exposed to airborne sounds that would result in
harassment as defined under the MMPA. Airborne noise would primarily be
an issue for pinnipeds that are swimming with heads above the waterline
or hauled out near the project site within the range of noise levels
elevated above the acoustic criteria. We recognize that pinnipeds in
the water could be exposed to airborne sound that may result in
behavioral harassment when looking with their heads above water. Most
likely, airborne sound would cause behavioral responses similar to
those discussed above in relation to underwater sound. For instance,
anthropogenic sound could cause hauled out pinnipeds to exhibit changes
in their normal behavior, such as reduction in vocalizations, or cause
them to temporarily abandon the area and move further from the source.
However, these animals would likely previously have been `taken'
because of exposure to underwater sound above the behavioral harassment
thresholds, which are generally larger than those associated with
airborne sound (i.e., 8 m and 36 to 58 m for phocid pinnipeds, 2 m and
12 to 18 m for otariid pinnipeds). Thus, the behavioral harassment of
these animals is already accounted for in these estimates of potential
take. Therefore, we do not believe that authorization of additional
incidental take resulting from airborne sound for pinnipeds is
warranted, and airborne sound is not discussed further.
Potential Effects on Marine Mammal Habitat
TAC's proposed pile removal and installation activities could have
localized, temporary impacts on marine mammal habitat, including prey,
by increasing in-water SPLs, and slightly decreasing water quality from
increased turbidity. Increased noise levels may affect acoustic habitat
(see Masking discussion above) and adversely affect marine mammal prey
in the vicinity of the project area (see discussion below). Elevated
levels of underwater noise would ensonify the project area where both
fishes and marine mammals occur and could affect foraging success.
Additionally, marine mammals may avoid the area during pile removal and
installation activities; however, displacement due to noise is expected
to be temporary and is not expected to result in long-term effects to
the individuals or populations.
Temporary and localized reduction in water quality would occur as a
result of in-water pile removal and installation 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 pile removal and installation
activities is relatively small compared to the available marine mammal
habitat.
The proposed pile removal and installation activities would also
remove an estimated 385 timber creosote-treated piles which would
potentially improve water quality. Given those piles would be replaced
by an estimated 86 piles; the total net reduction would be an estimated
299 piles, which would permanently decrease the in-water footprint of
Pier 5 and increase the area (by approximately 128.32 square ft [11.9
square m]) of the seafloor without manmade structures that is available
as marine mammal habitat in the Port of Adak.
In-Water Pile Removal and Installation Activities Effects on
Potential Prey--Pile removal and installation activities would produce
continuous (i.e., vibratory pile driving) and intermittent (i.e.,
impact driving) sounds. Sound may affect marine mammals through impacts
on the abundance, behavior, or distribution of prey species (e.g.,
crustaceans, cephalopods, fish, zooplankton). Marine mammal prey varies
by species, season, and location. Here, we describe studies regarding
the effects of noise on known marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay,
2009). Depending on their hearing anatomy and peripheral sensory
structures, which vary among species, fishes hear sounds using pressure
and particle motion sensitivity capabilities and
[[Page 12161]]
detect the motion of surrounding water (Fay et al., 2008). The
potential effects of noise on fishes depends on the overlapping
frequency range, distance from the sound source, water depth of
exposure, and species-specific hearing sensitivity, anatomy, and
physiology. Key impacts to fishes may include behavioral responses,
hearing damage, barotrauma (pressure-related injuries), and mortality.
Fish react to sounds that are especially strong and/or intermittent
low-frequency sounds, and behavioral responses such as flight or
avoidance are the most likely effects. Short duration, sharp sounds can
cause overt or subtle changes in fish behavior and local distribution.
The reaction of fish to noise depends on the physiological state of the
fish, past exposures, motivation (e.g., feeding, spawning, migration),
and other environmental factors. Hastings and Popper (2005) identified
several studies that suggest fish may relocate to avoid certain areas
of sound energy. Additional studies have documented effects of pile
driving on fish; several are based on studies in support of large,
multiyear bridge construction projects (e.g., Scholik and Yan, 2001;
Scholik and Yan, 2002; Popper and Hastings, 2009). Several studies have
demonstrated that impulse sounds might affect the distribution and
behavior of some fishes, potentially impacting foraging opportunities
or increasing energetic costs (e.g., Fewtrell and McCauley, 2012;
Pearson et al., 1992; Skalski et al., 1992; Santulli et al., 1999;
Paxton et al., 2017). However, some studies have shown no or slight
reaction to impulse sounds (e.g., Pena et al., 2013; Wardle et al.,
2001; Jorgenson and Gyselman, 2009).
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function likely is
restored when damaged cells are replaced with new cells. Halvorsen et
al. (2012a) showed that a TTS of 4 to 6 dB was recoverable within 24
hours for one species. Impacts would be most severe when the individual
fish is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012b; Casper et al., 2013).
The most likely impact to fishes from pile driving activities at
the project area would be temporary behavioral avoidance of the area.
The duration of fish avoidance of this area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution, and
behavior is anticipated.
Pile removal and installation activities have the potential to have
adverse impacts on forage fish in the project area in the form of
increased turbidity. Forage fish form a significant prey base for many
marine mammal species that occur in the project area. Turbidity within
the water column has the potential to reduce the level of oxygen in the
water and irritate the gills of prey fish in the proposed project area.
However, fish in the proposed project area would be able to move away
from and avoid the areas where increase turbidity may occur. Given the
limited area affected and ability of fish to move to other areas, any
effects on forage fish are expected to be minor or negligible.
In summary, given the short daily duration of sound associated with
individual pile driving and removal events and the relatively small
areas being affected, pile driving and removal activities associated
with the proposed action are not likely to have a permanent, adverse
effect on any fish habitat, or populations of fish species. Any
behavioral avoidance by fish of the disturbed area would still leave
significantly large areas of fish and marine mammal foraging habitat in
the nearby vicinity. Thus, we conclude that impacts of the specified
activities are not likely to have more than short-term adverse effects
on any prey habitat or populations of prey species. Further, any
impacts to marine mammal habitat are not expected to result in
significant or long-term consequences for individual marine mammals, or
to contribute to adverse impacts on their populations.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
proposed for authorization through the IHA, which will inform both
NMFS' consideration of ``small numbers,'' and the negligible impact
determinations.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which: (i) has the potential to injure
a marine mammal or marine mammal stock in the wild (Level A
harassment); or (ii) has the potential to disturb a marine mammal or
marine mammal stock in the wild by causing disruption of behavioral
patterns, including, but not limited to, migration, breathing, nursing,
breeding, feeding, or sheltering (Level B harassment).
Authorized takes would be by Level B harassment, as use of the
acoustic sources (i.e., impact and vibratory pile driving and removal)
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 mysticetes (low-frequency),
odontocetes (high-frequency), phocids, and otariids. The proposed
mitigation and monitoring measures are expected to minimize the
severity of the taking to the extent practicable. As described
previously, no serious injury or mortality is anticipated or proposed
to be authorized for this activity. Below we describe how the proposed
take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of permanent hearing impairment; (2) the
area or volume of water that will be ensonified above these levels in a
day; (3) the density or occurrence of marine mammals within these
ensonified areas; and, (4) the number of days of activities. We note
that while these factors can contribute to a basic calculation to
provide an initial prediction of potential takes, additional
information that can qualitatively inform take estimates is also
sometimes available (e.g., previous monitoring results or average group
size). Below, we describe the factors considered here in more detail
and present the proposed take estimates.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur AUD INJ of some degree (equated to
Level A harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
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experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007; Southall et al., 2021; Ellison et
al., 2012). Based on what the available science indicates and the
practical need to use a threshold based on a metric that is both
predictable and measurable for most activities, NMFS typically uses a
generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS generally predicts that marine
mammals are likely to be behaviorally harassed in a manner considered
to be Level B harassment when exposed to underwater anthropogenic noise
above root-mean-squared pressure received levels (RMS SPL) of 120 dB 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 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. TAC's proposed activity
includes the use of continuous (vibratory pile driving and removal) and
impulsive (impact pile driving) sources, and therefore the RMS SPL
thresholds of 120 and 160 dB re 1 [mu]Pa is/are applicable.
Level A Harassment--NMFS' ``2024 Update to: Technical Guidance for
Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing''
(Version 3.0, Technical Guidance, 2024) identifies and updates
underwater and in-air dual criteria to assess AUD INJ (Level A
harassment) to five different marine mammal groups (based on hearing
sensitivity) as a result of exposure to noise from two different types
of sources (impulsive or non-impulsive). TAC's proposed activity
includes the use of impulsive (impact pile driving) and non-impulsive
(vibratory pile driving and removal) sound sources.
NMFS AUD INJ thresholds are provided in table 4. The references,
analysis, and methodology used in the development of the thresholds 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">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>-other-acoustic-
tools.
Table 4--Thresholds Identifying the Onset of Auditory Injury
----------------------------------------------------------------------------------------------------------------
Auditory injury onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 222 dB; Cell 2: LE,LF,24h: 197 dB.
LE,LF,24h: 183 dB;.
High-Frequency (HF) Cetaceans.......... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 201 dB.
LE,MF,24h: 193 dB;.
Very High-Frequency (VHF) Cetaceans.... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 181 dB.
LE,HF,24h: 159 dB;.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 223 dB; Cell 8: LE,PW,24h: 195 dB.
LE,PW,24h: 183 dB;.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 230 dB; Cell 10: LE,OW,24h: 199 dB.
LE,OW,24h: 185 dB;.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak SPL thresholds
associated with impulsive sounds, these thresholds are recommended for consideration.
Note: Peak sound pressure (Lpk) 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, thresholds are abbreviated to be more
reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat'' is
being included to indicate peak sound pressure are flat weighted or unweighted within the generalized hearing
range of marine mammals (i.e., 7 Hz to 165 kHz). The subscript associated with cumulative sound exposure level
thresholds 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 thresholds could be exceeded in a multitude of ways (i.e., varying exposure levels and
durations, duty cycle). When possible, it is valuable for action proponents to indicate the conditions under
which these acoustic thresholds will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the proposed project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., pile driving and removal).
The project includes vibratory pile installation and removal as
well as impact pile driving. Vibratory pile drivers will be the primary
method of steel pile installation. Vibratory pile driving have
relatively lower sound levels than impact pile driving and are not
expected to cause AUD INJ to marine mammals. 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--Estimates of Mean Underwater Sound Levels (at 10 Meters) Generated During Vibratory and Impact Pile
Installation and Vibratory Pile Removal
----------------------------------------------------------------------------------------------------------------
Continuous sound sources dB peak dB RMS dB SEL Reference
----------------------------------------------------------------------------------------------------------------
Vibratory Pile Driving
----------------------------------------------------------------------------------------------------------------
30-inch Steel Piles................... NA 166 NA PR1 2023 Calculations.
<=24-inch Steel Piles................. NA 163 NA PR1 2023 Calculations.
[[Page 12163]]
12 to 16-inch Timber Piles............ NA 162 NA Caltrans, 2020.
----------------------------------------------------------------------------------------------------------------
Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
30-inch Steel Piles................... 210 190 177 Caltrans, 2015.
14 to 18-inch Steel Piles............. 200 185 175 Caltrans, 2020.
12 to 14-inch Timber Piles............ 180 170 160 Caltrans, 2020.
----------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; RMS = root mean square; SEL = sound exposure level.
Transmission loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater TL is:
TL = B * Log10 (R1/R2),
Where:
TL = transmission loss in dB
B = transmission loss coefficient
R1 = the distance of the modeled SPL from the driven pile, and
R2 = 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 Pier
5 Improvements 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.
Assuming practicable spreading and other assumptions regarding the
source characteristics and operational logistics (e.g., source level,
number of strikes per pile, number of piles per day), TAC calculated
distances to the Level A harassment and Level B harassment isopleths
and associated ensonified areas. Because an ensonified area associated
with Level A harassment is more technically challenging to predict due
to the need to account for a duration component, NMFS developed an
optional User Spreadsheet tool to assist applicants in assessing the
potential for Level A harassment without the need for complex modeling
(<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>-other-acoustic-tools). This
relatively simple tool can be used to calculate a Level A harassment
isopleth distance for use in conjunction with marine mammal density or
occurrence data to predict the amount of take that may occur incidental
to an activity. The resulting isopleth does not account for animal
movement and represents the distance at which an individual would have
to remain for the entire duration of pile driving or removal within a
24-hour period. As the amount of time considered in the calculation
becomes longer, the likelihood of an individual accumulating noise
energy above threshold at that distance becomes less realistic.
However, individuals may approach a source more closely than the
calculated distance in which case the amount of time needed to elicit
the onset of AUD INJ decreases. While the risk of AUD INJ is low
overall due to expected avoidance behavior, the User Spreadsheet offers
a practical alternative for estimating isopleth distances when more
sophisticated modeling methods are unavailable or are impractical.
Table 6 provides the inputs into the User Spreadsheet tool for
estimating distances to Level A harassment isopleths.
Table 6--User Spreadsheet Inputs
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Impact
--------------------------------------------------------------------------------------------------------------------------
30-inch Steel 30-inch Steel 18-inch Steel 12-inch Timber 30-inch Steel 30-inch Steel 18-inch Steel
Fender Piles Bearing Piles Fender Piles Piles Fender Piles Bearing Piles Fender Piles
--------------------------------------------------------------------------------------------------------------------------
Installation or
Removal Installation Installation Removal Installation Installation Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used......... A.1) Vibratory A.1) Vibratory A.1) Vibratory A.1) Vibratory E.1) Impact E.1) Impact E.1) Impact
Pile Driving. Pile Driving. Pile Driving. Pile Driving. Pile Driving. Pile Driving. Pile Driving
Source Level (SPL)........... 166 RMS......... 166 RMS......... 163 RMS......... 162 RMS......... 177 SEL........ 177 SEL........ 175 SEL
Transmission Loss Coefficient 15.............. 15.............. 15.............. 15.............. 15............. 15............. 15
Weighting Factor Adjustment 2.5............. 2.5............. 2.5............. 2.5............. 2.............. 2.............. 2
(kHz).
Activity Duration per Day 135............. 45.............. 675............. 1,200........... NA............. NA............. NA
(Minutes).
Number of Strikes per Pile... ................ ................ ................ ................ 600............ 1,200.......... 300
Number of Piles per Day...... 3............... 1............... 15.............. 60.............. 3.............. 1.............. 15
Distance of Sound Pressure 10.............. 10.............. 10.............. 10.............. 10............. 10............. 10
Level Measurement.
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 12164]]
Using the practical spreading model and assumptions identified in
table 5 and 6, TAC calculated, and NMFS has carried forward into this
analysis, the distances to the Level A harassment and Level B
harassment thresholds for marine mammals (table 7).
Table 7--Level A Harassment and Level B Harassment Isopleths From Vibratory and Impact Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment isopleths (m) Level B
Pile Type -------------------------------------------------------------------------------- harassment
LF HF VHF 1 PW OW isopleth (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
30-inch Steel Fender Piles.............................. 34.1 13.1 NA 43.9 14.8 11,659
30-inch Steel Bearing Piles............................. 16.4 6.3 NA 21.1 7.1 11,659
18-inch Steel Fender Piles.............................. 62.9 24.2 NA 81 27.3 7,356
12-inch Timber Piles.................................... 79.2 30.4 NA 102 34.3 6,310
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
30-inch Steel Fender Piles.............................. 586.1 74.8 NA 520.7 194.1 1,000
30-inch Steel Bearing Piles............................. 447.3 57.1 NA 397.4 148.1 1,000
18-inch Steel Fender Piles.............................. 794.3 101.3 NA 705.6 263 464
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ No takes of VHF species (e.g., harbor porpoises) have been requested by TAC and no take is being authorized by NMFS.
While the modeled ensonified area for the Level B harassment
isopleth for vibratory pile driving is 6,310 to 11,659 m depending on
the size and type of pile, the Level B harassment isopleth is actually
smaller as it is attenuated by land on three sides by the boundaries of
Sweeper Cove, and on the other side is partially attenuated by the
earthen fill and rock revetment breakwater that separates Sweeper Cove
and Kuluk Bay. The remaining area at the southeast end of the isopleth
is attenuated by land at 10,105 ft (3,080 m) at the farthest point. The
radial distance to the underwater noise thresholds for vibratory pile
driving would reach the shoreline opposite Pier 5 and then stop.
Marine Mammal Occurrence and Take Estimation
In this section we provide information about the occurrence of
marine mammals, including density or other relevant information which
will inform the take calculations. We describe how the information
provided is synthesized to produce a quantitative estimate of the take
that is reasonably likely to occur and proposed for authorization.
As described above, estimated density for marine mammal species
(humpback whale, minke whale, killer whale, Steller sea lion, and
harbor seal) within the project area were not available to directly
inform the take estimates. TAC conducted a literature review to
determine specific occurrence of marine mammals for Sweeper Cove and/or
Kuluk Bay, but most documents were too broad for the specific project
area. Two individuals (including a biologist for the U.S. Fish and
Wildlife Service's Alaska Maritime Wildlife Refuge) who have lived on
Adak Island for about 30 years provided details on marine mammal
species potential occurrence and sightings near the project area to TAC
via personal communication. The group size and predictable occurrence
of marine mammal species in the project area were also compiled from
reviews of scientific literature, previous IHA applications and
monitoring reports for similar construction activities in Alaska, as
well as information from local biologists. NMFS recognizes that while
anecdotal data provide some insight into the potential number of marine
mammals present within the action area, the data may have some biases
based on when personnel were observing for marine mammals (e.g., during
favorable weather) and these efforts were sparse. Additionally, there
have been no project-specific, or systematic surveys within Sweeper
Cove. Moreover, there is the potential for unusual events where more
marine mammals may be encountered (e.g., strong salmon runs in Sweeper
Cove). Therefore, TAC has requested slightly higher number of takes
than the scant data available may provide to ensure that enough take
has been authorized to conduct the project as needed.
Average group sizes used to inform estimated takes by Level B
harassment for all species with prior observations near the project
area are primarily based on those data. The estimated group size and
predictable occurrence of marine mammal species in the Port of Adak is
shown in table 8.
Table 8--Estimated Average Group Size and Frequency of Occurrence of Marine Mammal Species in the Port of Adak
----------------------------------------------------------------------------------------------------------------
Estimated
average group Frequency of occurrence in
Species size or the project area Reference
occurrence
----------------------------------------------------------------------------------------------------------------
Humpback Whale--Hawai[revaps]i Stock... 2 Yearly...................... Matthew Holsinger, Tom
Spittler, and Lisa
Spittler Personal
Communication with
Andrew Fisher, 2025.
Humpback Whale--Mexico-North Pacific 2 Yearly...................... Matthew Holsinger, Tom
Stock. Spittler, and Lisa
Spittler Personal
Communication with
Andrew Fisher, 2025.
Humpback Whale--Western North Pacific 2 Yearly...................... Matthew Holsinger, Tom
Stock. Spittler, and Lisa
Spittler Personal
Communication with
Andrew Fisher, 2025.
Minke Whale............................ 2 Yearly...................... Guerrero, 2008b.
Killer Whale--Eastern North Pacific 23 Yearly...................... Forney and Wade, 2006.
Alaska Resident Stock.
Killer Whale--Gulf of Alaska, Aleutian 8 Yearly...................... Forney and Wade, 2006.
Islands, and Bering Sea Transient
Stock.
Steller Sea Lions...................... 10 Monthly..................... Matthew Holsinger, Tom
Spittler, and Lisa
Spittler Personal
Communication with
Andrew Fisher, 2025.
[[Page 12165]]
Harbor Seal............................ 3 Daily....................... Matthew Holsinger, Tom
Spittler, and Lisa
Spittler Personal
Communication with
Andrew Fisher, 2025.
----------------------------------------------------------------------------------------------------------------
Humpback whales, minke whales, and killer whales are uncommon
within the project area. Therefore, TAC estimated that only one group
of each species and stock may be exposed to noise above harassment
thresholds during the effective period of the IHA. For these species,
TAC requested authorization to take one group per year (per stock) by
Level B harassment and one individual by Level A harassment. However,
this approach overestimates the potential for take. Therefore, NMFS has
reduced the amount of Level B harassment by the requested number of
Level A harassment exposures.
Steller sea lions and harbor seals are common in the project area.
For Steller sea lions, TAC estimated 10 Steller sea lions (table 8)
could be present and potentially taken each month activities could
occur (4 months). For harbor seals, TAC estimated three harbor seals
per day (table 8) could be present and potentially taken each day the
specified activities could occur (up to 126 days).
The resulting exposure estimates from these calculations are
provided in table 8. NMFS acknowledges that the number of estimated
exposures above higher threshold criteria, (e.g., sound exposures
exceeding Level A harassment criteria), also encompass 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.
Humpback Whale
The average group size for humpback whales for each stock estimated
in the project area was two animals per group on a yearly occurrence.
However, as described above, the available data is scant and humpbacks
are occasionally observed near the project area.
For estimating take by Level B harassment where monitoring data
confirmed the presence of the marine mammal species, NMFS concurred
with TAC's proposed approach. TAC requested take by Level B harassment
by predicting that one group of humpback whales would be sighted every
year, which was based on the applicant predicting this species would
occur within the project area. This was then multiplied by the average
group size for humpback whales (two individuals), to achieve a yearly
rate.
It is possible that humpback whales could enter the Level A
harassment zone during pile driving activities and stay long enough to
incur AUD INJ before TAC detects the animal and implements a shutdown.
As such, TAC requested and NMFS proposed to authorize a small amount of
take by Level A harassment of humpback whales. NMFS determined takes by
Level A harassment with the assumption that one individual may be
present in the Level A harassment zone.
Therefore, NMFS proposes to authorize a total of 6 takes by Level B
harassment and three takes by Level A harassment of humpback whales.
Based on the information on the occurrence of the three stocks in the
waters off the coast of Alaska (in the Aleutian Islands), the percent
probability of harassment occur to individuals of the Hawaii stock,
Mexico North Pacific stock, and Western North Pacific stock is 91
percent, 7 percent, and 2 percent, respectively.
Minke Whale
The average group size for minke whales estimated in the project
area was two animals per group on a yearly occurrence. TAC used an
average group size of two individuals based on observations of minke
whales around Adak Island, Alaska.
For estimating take by Level B harassment where monitoring data
confirmed the presence of the marine mammal species, NMFS concurred
with TAC's proposed approach. TAC estimates that one group of minke
whales could occur within the ensonified area during the specified
activities in a year. This was then multiplied by the average group
size for minke whales (two individuals), to achieve a yearly rate.
It is possible that minke whales could enter the Level A harassment
zone during pile driving activities and stay long enough to incur AUD
INJ before TAC detects the animal and implements a shutdown. As such,
TAC requested and NMFS proposed to authorize one take by Level A
harassment of minke whales.
Therefore, TAC requested, and NMFS proposes to authorize, a total
of two takes by Level B harassment and one take by Level A harassment
for minke whales.
Killer Whale
The average group size for killer whales detected in the project
area was 23 (Eastern North Pacific Alaska Resident stock) or 8 (Eastern
North Pacific Gulf of Alaska, Aleutian Islands, and Bering Sea
Transient stock) animals per group on a yearly occurrence, depending on
the stock.
For estimating take by Level B harassment where monitoring data
confirmed the presence of the marine mammal species, NMFS concurred
with TAC's proposed approach. TAC estimates that one group of killer
whales from each stock would be sighted every year. This was then
multiplied by the average group size for killer whales (23 or 8
individuals), to achieve a yearly rate.
TAC requested authorize a small amount of take by Level A
harassment of killer whales. NMFS determined takes by Level A
harassment is unlikely due to the small size of the Level A harassment
zone, establishment of a shutdown zone, and the high visibility of
this. NMFS is not proposing to authorize take by Level A harassment for
both stocks of killer whales.
Therefore, NMFS proposed to authorize a total of 23 and 8 takes by
Level B harassment for the Eastern North Pacific Alaska Resident stock
and Eastern North Pacific Gulf of Alaska, Aleutian Islands, and Bering
Sea Transient stock, respectively.
Steller Sea Lion
The average group size for Steller sea lions estimated in the
project area was 10 animals on a monthly occurrence. However, as
described above, the data are scant and stochastic events such as a
strong salmon run could result in more frequent occurrences.
[[Page 12166]]
For estimating take by Level B harassment where monitoring data
confirmed the presence of the marine mammal species, NMFS concurred
with TAC's proposed approach. TAC requested take by Level B harassment
by predicting that one group of Steller sea lions would be sighted
every month, which was based on the applicant predicting that this
species would occur within the project area. This was then multiplied
by the average group size for Steller sea lions (10 individuals), to
achieve a monthly rate.
It is possible that Steller sea lions could enter the Level A
harassment zone during pile driving activities and stay long enough to
incur AUD INJ before TAC detects the animal and implements a shutdown.
As such, TAC requested and NMFS proposed to authorize a small amount of
take by Level A harassment of Steller sea lions. NMFS determined takes
by Level A harassment with the assumption that 12 individuals may be
present in the Level A harassment zone based on the potential that
several small groups may remain near the mouth of streams foraging on
salmon runs at the west end of Sweeper Cove.
Therefore, NMFS proposes to authorize a total of 40 takes by Level
B harassment and 12 takes by Level A harassment for Steller sea lions.
Harbor Seal
The average group size for harbor seals estimated in the project
area was three harbor seals per group on a daily occurrence.
For estimating take by Level B harassment where monitoring data
confirmed the presence of the marine mammal species, NMFS concurred
with TAC's proposed approach. TAC requested take by Level B harassment
by predicting that one group of harbor seals would be sighted every
day, which was based on the applicant predicting this species would
more commonly occur within the project area. This was then multiplied
by the average group size for harbor seals (three individuals), to
achieve a daily rate.
It is possible that harbor seals could enter the Level A harassment
zone during pile driving activities and stay long enough to incur AUD
INJ before TAC detects the animal and implements a shutdown. As such,
TAC requested and NMFS proposed to authorize a small amount of take by
Level A harassment of harbor seals. NMFS determined takes by Level A
harassment with the assumption that one individual may be present per
day in the Level A harassment zone.
Therefore, NMFS proposes to authorize a total of 378 takes by Level
B harassment and 126 takes by Level A harassment for harbor seals.
Takes by Level A harassment for harbor seals are not requested nor are
they proposed for authorization.
Table 9--Proposed Take by Stock and Harassment Type and as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
Proposed authorized take
-------------------------------- Proposed take as
Species Stock Level A Level B a percentage of
harassment harassment stock abundance
----------------------------------------------------------------------------------------------------------------
Humpback Whale...................... Hawai[revaps]i......... 3 6 >1
Mexico-North Pacific... (*)
Western North Pacific.. >1
Minke Whale......................... Alaska................. 1 2 (*)
Killer Whale........................ Eastern North Pacific 0 23 1.2
Alaska Resident.
Eastern North Pacific 0 8 1.4
Gulf of Alaska,
Aleutian Islands, and
Bering Sea Transient.
Steller Sea Lion.................... Western................ 12 40 <1
Harbor Seal......................... Aleutian Islands....... 126 378 9
----------------------------------------------------------------------------------------------------------------
* Reliable abundance estimates for these stocks are currently unavailable.
\1\ 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. Therefore, the number of Level B harassment exposures
documented in a monitoring report may exceed the number of Level B harassment takes authorized but may not
exceed the sum of all take authorized.
The number of takes by Level A and Level B harassment were
estimated based on Port of Adak personnel that live and work near
Sweeper Cove. While their anecdotal data provides some level of
certainty in the potential number of marine mammals present within the
project area; the data may have some biases based on when personnel
were observing marine mammals in the field. Additionally, there have
been no project-specific, or systematic surveys within Sweeper Cove and
Kuluk Bay to provide a solid baseline for the number of marine mammals
that regularly use the area during the spring/summer/fall months.
Therefore, to provide a conservative scenario for the number of marine
mammals that may be encountered during the construction window (May
through September), the takes by Level A harassment were added to the
takes by Level B harassment. Furthermore, there is the potential for
unusual events where more marine mammals may be encountered (e.g.,
strong salmon runs in Sweeper Cover). Therefore, to account for the
uncertainty and variability in the number of marine mammals that could
be taken, the Level A and Level B harassment numbers are additive.
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 (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting the
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks, and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is
[[Page 12167]]
expected to reduce impacts to marine mammals, marine mammal species or
stocks, and their habitat, as well as subsistence uses. This considers
the nature of the potential adverse impact being mitigated (likelihood,
scope, range). It further considers the likelihood that the measure
will be effective if implemented (probability of accomplishing the
mitigating result if implemented as planned), the likelihood of
effective implementation (probability implemented as planned), and;
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost, and impact on
operations.
The mitigation requirements described in the following were
proposed by TAC in its adequate and complete application or are the
result of subsequent coordination between NMFS and TAC. TAC 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.
TAC must ensure that construction supervisors and crews, the
monitoring team and relevant TAC staff are trained prior to the start
of all pile driving activity, so that responsibilities, communication
procedures, monitoring protocols, and operational procedures are
clearly understood. New personnel joining during the project must be
trained prior to commencing work.
Along with the IHA application, TAC provided a comprehensive Marine
Mammal Monitoring and Mitigation Plan (4MP) for the Pier 5 Improvements
Project, which included additional general mitigation measures,
Protected Species Observer (PSO) requirements, PSO procedures,
mitigation measures for impact pile installation (pipe piles),
mitigation measures for vibratory pipe removal and installation,
mitigation measures for wood treated pilings, mitigation measures for
project-dedicated vessels, mitigation measures for vessel transit
(North Pacific right whales, Steller sea lions, and their designated
critical habitat), data collection, and reporting. Please see that
document for more detailed information.
Mitigation for Marine Mammals and Their Habitat
Visibility Conditions--Pile driving or removal would begin no
sooner than 30 minutes after sunrise to allow for 30-minute pre-
activity monitoring and would cease in time to allow for the 30-minutes
post-activity monitoring period. Pile driving and removal may not begin
or continue without sufficient daylight or weather conditions to
observe marine mammals within the clearance or shutdown zones.
Bubble Curtains--Bubble curtains would be used during impact pile
driving reduce in-water noise effects.
Clearance and Shutdown Zones--TAC proposed, and NMFS would require,
the establishment of clearance and shutdown zones identified in table
10 for pile installation and removal activities. The purpose of
``clearance'' of a particular zone is to prevent potential instances of
AUD INJ and more severe behavioral disturbance the maximum extent
practicable by delaying the commencement of impact pile driving 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 AUD INJ or severe behavioral disturbance
of sensitive species, by halting the activity. Additionally, to avoid
unauthorized takes, TAC would be required to 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. After shutdown, an activity may be
reinitiated once all clearance zones are clear of marine mammals for
the minimum species-specific periods (15 minutes for odontocetes or
pinnipeds and 30 minutes for mysticetes). Specified activities would
also be delayed or shutdown if PSOs cannot visually observe the zones
in table 10. In-water activities that do not include the specified
activities but require heavy equipment would also shutdown if a marine
mammal approaches within 10 m to avoid direct interaction. The shutdown
zone for mysticetes (humpback whales and minke whales), phocids (harbor
seals), and otariids (Steller sea lions) would be 200 m to simplify
mitigation measures for PSOs across all species and specified activity
types. Larger shutdown zones would not be practicable for these hearing
groups/species as TAC would have to shutdown too often (which could
extend the time needed to complete the specified activities that
produce in-air and underwater sound) and it may be difficult to
reliably detect (and implement mitigation measures by PSOs at those
distances) smaller species such as harbor seals.
Table 10--Proposed Shutdown Zones
----------------------------------------------------------------------------------------------------------------
Shutdown zones (m)
Activity Pile diameter and -----------------------------------------------------------
type LF HF VHF PW OW
----------------------------------------------------------------------------------------------------------------
Vibratory....................... 30-inch Steel 35 15 NA 45 15
Fender.
Vibratory....................... 30-inch Steel 20 10 NA 25 15
Bearing.
Vibratory....................... 18-inch Steel 65 25 NA 85 30
Fender.
Vibratory....................... 12-inch Timber.... 80 30 NA 100 35
Impact.......................... 30-inch Steel 200 100 NA 200 200
Fender.
Impact.......................... 30-inch Steel 200 100 NA 200 200
Bearing.
Impact.......................... 18-inch Steel 200 100 NA 200 200
Fender.
----------------------------------------------------------------------------------------------------------------
Soft Start--The use of soft-start procedures provide warning,
giving marine mammals a chance to leave the area prior to the hammer
operating at full capacity. For impact pile driving, contractors would
be required to provide an initial set of three strikes from the hammer
at reduced energy (at no more than half the operational power), with
each strike followed by a 30-second waiting period, then two subsequent
reduced-power-strike sets. Soft start would be implemented at the start
of each day's impact pile driving and at any time following cessation
of impact pile driving for a period of 30 minutes or longer (and PSO
visual monitoring has also stopped). Soft start is not required during
vibratory pile driving and removal activities.
[[Page 12168]]
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
<bullet> Mitigation and monitoring effectiveness.
The monitoring and reporting requirements described in the
following were proposed by TAC in its adequate and complete application
and/or are the result of subsequent coordination between NMFS and TAC.
TAC has agreed to the requirements. NMFS describes these below as
requirements and has included them in the proposed IHA.
Marine mammal monitoring must be conducted in accordance with the
4MP. Marine mammal monitoring during pile driving and removal
activities must be conducted by NMFS-approved PSOs who have no other
assigned tasks during monitoring periods. At least one PSO would have
prior experience performing the duties of a PSO during pile removal and
installation activities pursuant to a NMFS-issued Incidental Take
Authorization. Visual monitoring would be conducted by at least two PSO
positioned at suitable vantage points (i.e., breakwater that separates
Sweeper Cove from Kuluk Bay, Pier 5, Fuel Pier, or the bluff along the
south side of Sweeper Cove opposite Pier 5). At least one PSO would
have an unobstructed view of all water within the shutdown zone and
would be stationed at or near the pier and/or breakwater. Remaining
PSOs would be placed at one or more of the observer monitoring
locations identified in the 4MP, in order to observe as much as the
Level A and Level B harassment zone as possible. All PSOs would be
required to use standard equipment such as reticle binoculars (7 by 50
or better), Big-Eye binoculars, spotting scopes (30 times),
clinometers, and range finders. A contact list, field guide,
instructional handbook, and maps would also be available to PSOs.
Details regarding PSO qualifications and monitoring requirements can be
found 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>.
Reporting
TAC will submit a draft marine mammal monitoring report to NMFS
within 90 calendar days after the completion of pile driving
activities, or 60 days prior to the requested issuance of any
subsequent IHA for similar activities at the same location, whichever
comes first. 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/incidentaltake-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidentaltake-authorizations-construction-activities</a>. In summary, the
report would include, but not be limited to, information regarding
activities that occurred, marine mammal sighting data, and whether
mitigative actions were taken or could not be taken. TAC would also be
required to submit reports on any observed injured or dead marine
mammals. If the death or injury was clearly caused by the specified
activity, TAC 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. TAC would not resume its activities until
notified by NMFS.
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, our analysis applies to all the species listed
in table 2, given that many of the anticipated effects of this project
on different marine mammal stocks are expected to be relatively similar
in nature. Where there are meaningful differences
[[Page 12169]]
between species or stocks, or groups of species, in anticipated
individual responses to activities, impact of expected take on the
population due to differences in population status, or impacts on
habitat, they are described independently in the analysis below.
Specified activities associated with the TAC's Pier 5 Improvements
Project, as outlined previously, have the potential to disturb or
displace as well as cause AUD INJ to marine mammals. Specifically, the
specified activities may result in take, in the form of Level B
harassment and Level A harassment, from underwater sounds generated by
pile driving. Potential takes could occur if marine mammals are present
in zones ensonified above the thresholds for Level B harassment or
Level A harassment, identified above, while activities are underway.
No serious injury or mortality would be expected, even in the
absence of required mitigation measures, given the nature of the
activities. The potential for harassment would be minimized through the
implementation of planned mitigation measures (see Proposed Mitigation
section).
Take by Level A harassment is proposed for five species (humpback
whale, minke whale, killer whale, Steller sea lion, and harbor seal) as
the shutdown zone is so large that it is possible that a humpback
whale, minke whale, killer whale, Steller sea lion, or harbor seal
could enter the Level A harassment zone and remain within the zone for
a duration long enough to incur AUD INJ before being detected.
Any take by Level A harassment is expected to arise from, at most,
a small degree of AUD INJ (i.e., minor degradation of hearing
capabilities within regions of hearing that align most completely with
the energy produced by impact pile driving such as the low-frequency
region below 2 kHz), not severe hearing impairment or impairment within
the ranges of greatest hearing sensitivity. Animals would need to be
exposed to higher levels and/or longer duration than are expected to
occur here in order to incur any more than a small degree of AUD INJ.
TAC would also shut down pile driving activities if marine mammals
enter the shutdown zones (table 10) further minimizing the likelihood
and degree of AUD INJ that would be incurred. Given the small degree
anticipated, any AUD INJ potential incurred would not be expected to
affect the reproductive success or survival of any individuals, much
less result in adverse impacts on the species or stock.
Additionally, some subset of the individuals that are behaviorally
harassed could also simultaneously incur some small degree of TTS for a
short duration of time. However, since the hearing sensitivity of
individuals that incur TTS is expected to recover completely within
minutes to hours, it is unlikely that the brief hearing impairment
would affect the individual's long-term ability to forage and
communicate with conspecifics, and would therefore not likely impact
reproduction or survival of any individual marine mammal, let alone
adversely affect rates of recruitment or survival of the species or
stock.
As described above, NMFS expects that marine mammals would likely
move away from an aversive stimulus, especially at levels that would be
expected to result in AUD INJ, given sufficient notice through use of
soft start.
Effects on individuals that are taken by Level B harassment in the
form of behavioral disruption, on the basis of reports in the
literature as well as monitoring from other similar activities, would
likely be limited to reactions such as avoidance, increased swimming
speeds, increased surfacing time, or decreased foraging (if such
activity were occurring) (e.g., Thorson and Reyff, 2006). Most likely,
individuals would simply move away from the sound source and
temporarily avoid the area where pile driving is occurring. If sound
produced by pile removal and installation activities is sufficiently
disturbing, animals are likely to simply avoid the area while the
activities are occurring. We expect that any avoidance of the project
area by marine mammals would be temporary in nature and that any marine
mammals that avoid the project area during pile removal and
installation activities would not be permanently displaced. Short-term
avoidance of the project area and energetic impacts of interrupted
foraging or other important behaviors is unlikely to affect the
reproduction or survival of individual marine mammals, and the effects
of behavioral disturbance on individuals is not likely to accrue in a
manner that would affect the rates of recruitment or survival of any
affected stock.
As described in the Description of Marine Mammal in the Area of
Specified Activities section, there are several haulouts in the
Aleutian Islands. The ensonified area from pile driving activities that
would occur during this project overlaps with the 23 miles (37 km) area
around only haulouts in this lesser used category, including Argonne
Point, Cape Moffet, Head Rock, and Kagalaska. The ensonified area
overlaps ESA-designated critical habitat for Western DPS of Steller sea
lion. Specifically, the Level B harassment ensonified area overlaps
with the aquatic zones of designated major haulouts. The ensonified
area Level B harassment zone related to implementation of the proposed
project, described in the Estimated Take of Marine Mammals section,
overlaps with the designated aquatic zone of the designated major
haulouts. No terrestrial or in-air critical habitat of any major
haulout overlaps with the project area. The effects from the pile
driving activities would be insignificant and temporary to designated
critical habitat for Steller sea lions.
The Pier 5 Improvements Project is also not expected to have
significant adverse effects on affected marine mammals' habitats. The
pile removal and installation activities would not modify existing
marine mammal habitat for a significant amount of time. The activities
may cause some fish to leave the area of disturbance, thus temporarily
impacting marine mammals' foraging opportunities in a limited portion
of the foraging range. We do not expect pile driving activities to have
significant consequences to marine invertebrate populations. Given the
short duration of the activities and the relatively small area of the
habitat that may be affected, the impacts to marine mammal habitat,
including fish and invertebrates, are not expected to cause significant
or long-term negative consequences. Further, the new improvements to
Pier 5 would be contained within the footprint of the existing pier so
no permanent impacts to habitat are expected to occur.
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> Level A harassment of four species proposed for
authorization are expected to be of a small degree;
<bullet> Effects on species that serve as prey for marine mammals
from the activities are expected to be short-term and, therefore, any
associated impacts on marine mammal feeding are not expected to result
in significant or long-term consequences for individuals, or to accrue
to adverse impacts on their populations;
<bullet> The lack of anticipated significant or long-term negative
effects to marine mammal habitat; and
<bullet> The efficacy of the mitigation measures in reducing the
effects of the
[[Page 12170]]
specified activities on all species and stocks.
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 sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. When the predicted number of
individuals to be taken is fewer than one-third of the species or stock
abundance, the take is considered to be of small numbers. Additionally,
other qualitative factors may be considered in the analysis, such as
the temporal or spatial scale of the activities.
The instances of take NMFS proposes to authorize are below one-
third of the estimated stock abundance for all stocks (table 9). The
number of animals that we expect to authorize to be taken from these
stocks would be considered small relative to the relevant stocks'
abundances even if each estimated taking occurred to a new individual,
which is an unlikely scenario.
The most recent abundance estimate for the Mexico-North Pacific
stock of humpback whale is likely unreliable as it is more than 8 years
old. The most relevant estimate of this stock's abundance in the Bering
Sea and Aleutian Islands is 918 humpback whales (Wade, 2021), so the 2
proposed takes by Level B harassment and 1 proposed takes by Level A
harassment, is small relative to the estimated abundance (0.3 percent),
even if each proposed take occurred to a new individual.
A lack of an accepted stock abundance value for the Alaska stock of
minke whale did not allow for the calculation of an expected percentage
of the population that would be affected. The most relevant estimate of
partial stock abundance is 1,233 minke whales in coastal waters of the
Alaska Peninsula and Aleutian Islands (Zerbini et al., 2006), so the 2
proposed takes by Level B harassment, and 1 proposed takes by Level A
harassment, compared to the abundance estimate, shows that less than 1
percent of the stock would be expected to be impacted.
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.
Alaskan Natives have hunted marine mammals in the Aleutian Islands
of Alaska for subsistence uses for hundreds of years (ADF&G 1997). In
2008, residents of Adak harvested four harbor seals and eight Steller
sea lions. Hunting for subsistence uses usually occurs in October and
November and does not generally occur within the harbor area of Adak
Island (ADF&G 2009). The Pier 5 Improvement Project is located in an
already developed area where commercial and human activities occur. The
proposed activities will not take place in or near a traditional Arctic
subsistence hunting area and is not likely to impact subsistence
activities or the availability of any marine mammal for subsistence
uses. No plan of cooperation is required for this project.
Based on the description of the specified activity, NMFS has
preliminarily determined that there will not be an unmitigable adverse
impact on subsistence uses from TAC's proposed activities.
Endangered Species Act
Section 7(a)(2) of the ESA (16 U.S.C. 1531 et seq.) requires that
each Federal agency insure that any action it authorizes, funds, or
carries out is not likely to jeopardize the continued existence of any
endangered or threatened species or result in the destruction or
adverse modification of designated critical habitat. To ensure ESA
compliance for the issuance of IHAs, NMFS consults internally whenever
we propose to authorize take for endangered or threatened species, in
this case with the Alaska Regional Office.
NMFS Office of Protected Resources (OPR) is proposing to authorize
take of Mexico DPS of humpback whale, Western North Pacific DPS of
humpback whale, and Western DPS of Steller sea lion which are listed
under the ESA. NMFS OPR has requested initiation of section 7
consultation with the NMFS Alaska Regional Office for the issuance of
this IHA. NMFS will conclude the ESA section 7 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 TAC authorizing the take of marine mammals incidental
to the Pier 5 Improvements Project at Adak Island, Alaska, provided the
previously mentioned mitigation, monitoring, and reporting requirements
are incorporated. A draft of the proposed IHA can be found at: <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA. 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
[[Page 12171]]
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);
and,
(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.
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: March 10, 2026.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2026-04857 Filed 3-11-26; 8:45 am]
BILLING CODE 3510-22-P
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