Notice2024-16412
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to U.S. Coast Guard Fast Response Cutter Homeporting in Seward and Sitka, Alaska
Primary source
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Published
July 25, 2024
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from the United States Coast Guard (USCG) for authorization to take marine mammals incidental to fast response cutter (FRC) homeporting in Seward and Sitka, Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue two incidental harassment authorizations (IHAs) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on possible one-time, 1- year renewals that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorizations and agency responses will be summarized in the final notice of our decision.
Full Text
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<title>Federal Register, Volume 89 Issue 143 (Thursday, July 25, 2024)</title>
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[Federal Register Volume 89, Number 143 (Thursday, July 25, 2024)]
[Notices]
[Pages 60359-60385]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-16412]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XD989]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to U.S. Coast Guard Fast Response
Cutter Homeporting in Seward and Sitka, Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorizations; request
for comments on proposed authorizations and possible renewals.
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SUMMARY: NMFS has received a request from the United States Coast Guard
(USCG) for authorization to take marine mammals incidental to fast
response cutter (FRC) homeporting in Seward and Sitka, Alaska. Pursuant
to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments
on its proposal to issue two incidental harassment authorizations
(IHAs) to incidentally take marine mammals during the specified
activities. NMFS is also requesting comments on possible one-time, 1-
year renewals that could be issued under certain circumstances and if
all requirements are met, as described in Request for Public Comments
at the end of this notice. NMFS will consider public comments prior to
making any final decision on the issuance of the requested MMPA
authorizations and agency responses will be summarized in the final
notice of our decision.
DATES: Comments and information must be received no later than August
26, 2024.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
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#87ced3d7a9e4ebe2f1e2e9f4f3eee9e2c7e9e8e6e6a9e0e8f1"><span class="__cf_email__" data-cfemail="feb7aaaed09d929b889b908d8a97909bbe90919f9fd0999188">[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: Alyssa Clevenstine, Office of
Protected Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the monitoring and
reporting of the takings. 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 IHAs qualify 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 requests.
Summary of Request
On January 19, 2024, NMFS received a request from the USCG for two
IHAs to take marine mammals incidental to pile driving (installation
and removal) associated with construction of two FRC homeporting docks
in Seward and Sitka, Alaska. Following NMFS' review of the application,
the USCG submitted revised versions on April 3, 2024, June 6, 2024, and
June 11, 2024. The application was deemed adequate and complete on June
11, 2024. The USCG's request is for take of 11 species (18 stocks) of
marine mammals by Level B harassment and, for a subset of five these
species, Level A harassment. Neither the USCG nor NMFS expect serious
injury or mortality to result from this activity and, therefore, IHAs
are appropriate.
Description of Proposed Activity
Overview
The USCG proposes to construct shore-side facilities and associated
infrastructure at Moorings Seward to homeport one FRC located in the
Seward Marine Industrial Center (SMIC) boat basin, and demolishing and
constructing shore side facilities at Moorings Sitka in Sitka Harbor to
[[Page 60360]]
support a second FRC. The shore-side facilities and associated
infrastructure for Moorings Seward would be constructed parallel to the
existing SMIC dock. Construction of a new floating dock at Moorings
Sitka would be attached to the existing pier. The projects are needed
to provide adequate vessel berthing capability to support modern USCG
cutters and ultimately, readiness as part of the USCG's overall
mission. The USCG would use a variety of methods, including impact,
down-the-hole (DTH), and vibratory pile driving, to install and remove
piles, including concrete, steel, plastic, and timber piles. These
methods of pile driving would introduce underwater sounds that may
result in take, by Level A and Level B harassment, of marine mammals.
Pile removal may occur by vibratory, cutting, or clipping methods.
Cutting and clipping are not anticipated to have the potential to
result in incidental take of marine mammals because they are either
above water, do not last for sufficient duration to present the
reasonable potential for disruption of behavioral patterns, do not
produce sound levels with likely potential to result in marine mammal
harassment, or some combination of the above.
Dates and Duration
Each IHA would be effective for 1 year from the date of issuance.
Pile extraction and installation activities at Moorings Seward would
occur for a total of 22 non-consecutive days, of which pile removal is
anticipated to take 2 days and pile installation is anticipated to take
a maximum of 20 days (15 days to complete installation plus 5
additional days to account for potential weather-related delays). Pile
removal and installation activities at Moorings Sitka would occur for a
total of 117 non-consecutive days, of which pile removal is anticipated
to take 3 days and pile installation is anticipated to take a maximum
of 114 days (89 days to complete installation plus 25 additional days
to account for potential weather-related delays).
Specific Geographic Region
The current USCG Moorings Seward is located within the City of
Seward Harbor while the SMIC (where the new Moorings will be
constructed) is located approximately 3.5 miles southeast of Seward
Harbor on the east side of Resurrection Bay (figure 1). The SMIC
currently occupies approximately 200 acres (0.809 square kilometer
(km\2\)) on the eastern shore of Resurrection Bay and maintains an
enclosed basin protected by rip-rap seawall with a floating dock.
Depths in the vicinity of the SMIC are dredged to an approximate depth
of -21 feet (ft; -6.4 meters (m)) below mean lower low water (MLLW) in
the boat basin and up to -25 ft (-7.6 m) MLLW at the North Dock.
USCG Moorings Sitka is located on the northeast side of Japonski
Island within Sitka Harbor on the Sitka Channel separating Japonski
Island from the larger Baranof Island (figure 2). The shore side and
in-water cutter facilities at Moorings Sitka currently occupy a 1.13-
acre (0.005 km\2\) upland site with adjacent waterside structures on
the southeastern shore of Japonski Island. Currently, only one dock is
present at Moorings Sitka and supports USCG Cutter Kukui. The
bathymetry of the narrow Sitka Channel, less than 1,000 ft (304.8 m)
wide at points, is steep at the sides and reaches approximately 30 ft
(9.1 m) MLLW at the end of the pier where the moorings facility is
located.
BILLING CODE 3510-22-P
[[Page 60361]]
[GRAPHIC] [TIFF OMITTED] TN25JY24.002
[[Page 60362]]
[GRAPHIC] [TIFF OMITTED] TN25JY24.003
BILLING CODE 3510-22-C
Detailed Description of the Specified Activity
At Moorings Seward, reconfiguration of the SMIC floating dock would
be required to allow for construction of a new FRC floating dock.
Extraction of 10 existing 14-inch (35.56 centimeter (cm)) steel piles
would occur over 2 days at a rate of five piles per day, potentially
using vibratory methods (table 1), pile cutting, or diamond wire
sawing. Pile cutting and diamond wire sawing are not expected to cause
take of marine mammals because they occur either above water, do not
last for sufficient duration to present the reasonable potential for
disruption of behavioral patterns, do not produce sound levels with
likely potential to result in marine mammal harassment, or some
combination of the above, and are thus not addressed further.
Installation of 30 30-inch (76.2 cm) concrete piles would occur over a
maximum of 20 days using DTH, vibratory, and impact driving.
Installation of a single concrete pile would require the following
sequence: up to 3 hours of DTH (rock socketing) drilling to create a
socket in the bedrock, followed by 10 minutes using a vibratory pile
driver to settle the pile into its socket, and finally proofing the
pile using 5 strikes from an impact driver to ensure the pile is fully
embedded at an expected rate of two
[[Page 60363]]
piles per day, plus 5 days of buffer (table 2).
At Moorings Sitka, removal of existing mooring dolphins and float,
owned by the City of Sitka, would be required to allow for construction
of a new sea-going buoy tender pier and FRC floating dock. Extraction
of 10 piles (four 24-inch (60.96 cm) concrete piles and six 14-inch
timber piles) would occur over a maximum of 3 days, with vibratory
extraction of the timber piles requiring 2 days and 1 day to remove the
concrete piles, potentially using vibratory methods (table 3), pile
cutting, or diamond wire sawing. Installation of 178 piles (118 30-inch
concrete piles, 54 13-inch (33.02 cm) plastic piles, and six 14-inch
timber piles) would occur over a maximum of 117 days using DTH,
vibratory, and impact driving. Installation of plastic piles and timber
piles would only require impact hammers. Installation of a single
concrete pile would require the same sequence described above for
Moorings Seward: up to 3 hours of DTH drilling to create a socket in
the bedrock, followed by 10 minutes using a vibratory pile driver to
settle the pile into its socket, and finally proofing the pile using 5
strikes from an impact drive to ensure the pile is fully embedded at an
expected rate of two piles per day, plus 25 days of buffer (table 4).
Table 1--Pile Removal Methods and Durations at USCG Moorings Seward
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Estimated
Removal method and pile type Number of Duration per pile Piles removed duration
piles per day (days)
----------------------------------------------------------------------------------------------------------------
Vibratory extraction of 14-in steel piles 10 30 min..................... 5 2
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Note: A total of 10 steel piles will be removed over a total of 2 days (rate 5 piles/day). Pile cutting and
diamond wire sawing may also be used but these methods are not expected to cause take of marine mammals.
Table 2--Pile Installation Methods and Durations at USCG Moorings Seward
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Estimated
Installation method and pile type Number of Duration or strikes per Piles driven duration
piles pile per day (days)
----------------------------------------------------------------------------------------------------------------
DTH drilling of 30-in concrete piles..... 30 180 min.................... 2 20
Vibratory driving of 30-in concrete piles 30 10 min..................... 2
Impact driving of 30-in concrete piles... 30 5 strikes per pile......... 2
----------------------------------------------------------------------------------------------------------------
Note: A total of 30 concrete guide piles will be installed via all methods listed above. Installation of a
single concrete pile would require the following sequence: up to 3 hours of DTH, followed by 10 minutes using
a vibratory pile driver, and proofing the pile using 5 strikes from an impact hammer (rate 2 piles per day
plus 5 days of buffer).
Table 3--Pile Removal Methods and Durations at USCG Moorings Sitka
----------------------------------------------------------------------------------------------------------------
Estimated
Removal method and pile type Number of Duration per pile Piles removed duration
piles per day (days)
----------------------------------------------------------------------------------------------------------------
Vibratory extraction concrete and 10 30 min.................... 5 3
timber piles.
----------------------------------------------------------------------------------------------------------------
Note: A total of 10 piles (four concrete piles and six timber piles) will be removed over a total of 3 days
(rate 5 piles per day). The applicant expects it will require 2 days to remove the six timber piles and 1 day
to remove the four concrete piles. Pile cutting and diamond wire sawing may also be used but these methods are
not expected to cause take of marine mammals.
Table 4--Pile Installation Methods and Durations at USCG Moorings Sitka
----------------------------------------------------------------------------------------------------------------
Estimated
Installation method and pile type Number of Duration or strikes per Piles driven duration
piles pile per day (days)
----------------------------------------------------------------------------------------------------------------
Impact driving plastic fender piles... 54 100 strikes per pile.... 2 27
Impact driving timber guide piles..... 6 160 strikes per pile.... 2 3
DTH drilling concrete piles........... 118 180 min................. 2 84
Vibratory driving concrete piles...... 118 10 min.................. 2
Impact pile driving concrete piles.... 118 5 strikes per pile...... 2
----------------------------------------------------------------------------------------------------------------
Note: A total of 178 piles (118 concrete piles, 54 plastic piles, and six timber piles) will be installed via
all methods listed above. Installation of plastic and timber piles will require impact driving only.
Installation of a single concrete pile would require the following sequence: up to 3 hours of DTH, followed by
10 minutes using a vibratory pile driver, and proofing the pile using 5 strikes from an impact hammer (rate 2
piles per day plus 25 days of buffer).
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/
[[Page 60364]]
national/marine-mammal-protection/marine-mammal-stock-assessments) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 5 lists all species or stocks for which take is expected and
proposed to be authorized for the activities at Seward and Sitka, 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
either NMFS' U.S. Alaska SARs or U.S. Pacific SARs. All values
presented in table 5 are the most recent available at the time of
publication (including from the draft 2023 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 5--Marine Mammal Species \1\ Likely Impacted by the Specified Activities
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ESA/ MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\2\ abundance survey) \3\ SI \4\
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Family Eschrichtiidae
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Gray Whale.......................... Eschrichtius robustus.. Eastern North Pacific.. -, -, N 26,960 (0.05, 25,849, 801 131
2016).
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Family Balaenopteridae (rorquals)
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Fin Whale........................... Balaenoptera physalus.. Northeast Pacific...... E, D, Y UND (UND, UND, 2013).. UND 0.6
Humpback Whale...................... Megaptera novaeangliae. Hawai[revaps]i......... -, -, N 11,278 (0.56, 7,265, 127 27.09
2020).
Humpback Whale...................... Megaptera novaeangliae. Mexico-North Pacific... T, D, Y N/A (N/A, N/A, 2006).. UND 0.57
Minke Whale \5\..................... Balaenoptera Alaska................. -, -, N N/A (N/A, N/A, N/A)... UND 0
acutorostrata.
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Family Delphinidae
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Killer Whale........................ Orcinus orca........... Eastern North Pacific -, -, N 1,920 (N/A, 1,920, 19 1.3
Alaska Resident. 2019).
Killer Whale........................ Orcinus orca........... Eastern North Pacific -, -, N 587 (N/A, 587, 2012).. 5.9 0.8
Gulf of Alaska,
Aleutian Islands and
Bering Sea Transient.
Killer Whale........................ Orcinus orca........... Eastern Northern -, -, N 302 (N/A, 302, 2018).. 2.2 0.2
Pacific Northern
Resident.
Killer Whale........................ Orcinus orca........... West Coast Transient... -, -, N 349 (N/A, 349, 2018).. 3.5 0.4
Pacific White-Sided Dolphin......... Lagenorhynchus North Pacific.......... -, -, N 26,880 (N/A, N/A, UND 0
obliquidens. 1990).
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Family Phocoenidae (porpoises)
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Dall's Porpoise \6\................. Phocoenoides dalli..... Alaska................. -, -, N UND (UND, UND, 2015).. UND 37
Harbor Porpoise..................... Phocoena phocoena...... Gulf of Alaska......... -, -, Y 31,046 (0.21, N/A, UND 72
1998).
Harbor Porpoise \7\................. Phocoena phocoena...... Yakutat/Southeast -, -, N N/A (N/A, N/A, 1997).. UND 22.2
Alaska Offshore Waters.
Family Otariidae (eared seals and
sea lions).
Northern Fur Seal................... Callorhinus ursinus.... Eastern Pacific........ -, D, Y 626,618 (0.2, 530, 11,403 373
376, 2019).
Steller Sea Lion.................... Eumetopias jubatus..... Western................ E, D, Y 49,837 (N/A, 49,837, 299 267
2022).
Steller Sea Lion.................... Eumetopias jubatus..... Eastern................ -, -, N 36,308 (N/A, 36,308, 2,178 93.2
2022).
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Family Phocidae (earless seals)
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Harbor Seal......................... Phoca vitulina......... Prince William Sound... -, -, N 44,756 (N/A, 41,776, 1,253 413
2015).
Harbor Seal......................... Phoca vitulina......... Sitka/Chatham Strait... -, -, N 13,289 (N/A, 11,883, 356 77
2015).
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\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>).
\2\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or
which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is
automatically designated under the MMPA as depleted and as a strategic stock.
\3\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region</a>. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, vessel strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A
CV associated with estimated mortality due to commercial fisheries is presented in some cases.
\5\ No population estimates have been made for the number of minke whales in the entire North Pacific. Some information is available on the numbers of
minke whales in some areas of Alaska, but in the 2009, 2013, and 2015 offshore surveys, so few minke whales were seen during the surveys that a
population estimate for the species in this area could not be determined (Rone et al., 2017). Therefore, this information is N/A (not available).
\6\ Previous abundance estimates covering the entire stock's range are no longer considered reliable and the current estimates presented in the SARs and
reported here only cover a portion of the stock's range. Therefore, the calculated Nmin and PBR is based on the 2015 survey of only a small portion of
the stock's range. PBR is considered to be biased low since it is based on the whole stock whereas the estimate of mortality and serious injury is for
the entire stock's range.
[[Page 60365]]
\7\ Abundance estimates assumed that detection probability on the trackline was perfect; work is underway on a corrected estimate. Additionally,
preliminary data results based on environmental DNA analysis show genetic differentiation between harbor porpoise in the northern and southern regions
on the inland waters of southeast Alaska. Geographic delineation is not yet known. Data to evaluate population structure for harbor porpoise in
Southeast Alaska have been collected and are currently being analyzed. Should the analysis identify different population structure than is currently
reflected in the Alaska SARs, NMFS will consider how to best revise stock designations in the future.
As indicated above, all 11 species (with 18 managed stocks) in
table 5 temporally and spatially co-occur with the activities to the
degree that take is reasonably likely to occur at either location. All
species that could potentially occur in the proposed project areas are
included in section 4 and tables 3-1 and 3-2 of the USCG's IHA
application. While the AT1 Transient stock of killer whales has been
reported in the area of Moorings Seward, the stock consists of only 7
individuals, and the temporal and/or spatial occurrence of this species
in the project area during the short proposed project timeframe is such
that take is not expected to occur. Therefore, they are not discussed
further in this notice. In addition, the southcentral and southeastern
stocks of northern sea otter (Enhydra lutris kenyoni) may be found in
Seward and Sitka, respectively. However, this species is managed by the
U.S. Fish and Wildlife Service and is not considered further in this
document.
Gray whale--Two populations of gray whales are recognized, the
eastern and a western North Pacific (ENP and WNP). Whales from the WNP
are known to feed in the Okhotsk Sea and off of Kamchatka before
migrating south to poorly known wintering grounds, possibly in the
South China Sea. The ENP stock of gray whales inhabit California and
Mexico in the winter months, and the Chukchi, Beaufort, and Bering Seas
in northern Alaska in the summer and fall. The migration pattern of
gray whales appears to follow a route along the western coast of
Southeast Alaska, traveling northward from British Columbia through
Hecate Strait and Dixon Entrance, passing the west coast of Baranof
Island from late March to May and then return south in October and
November (Jones et al., 1984; Ford et al., 2013). The two populations
have historically been considered geographically isolated from each
other; however, data from satellite-tracked whales indicate that there
is some overlap between the stocks. Two WNP whales were tracked from
Russian foraging areas along the Pacific rim to Baja California (Mate
et al., 2011). Between 22-24 WNP whales are known to have occurred in
the eastern Pacific through comparisons of ENP and WNP photo-
identification catalogs (Weller et al., 2011). Therefore, a portion of
the WNP population is assumed to migrate, at least in some years, to
the eastern Pacific during the winter breeding season. However, it is
extremely unlikely that a gray whale in close proximity to the proposed
project areas would be one of the few WNP whales that have been
documented in the eastern Pacific. The likelihood that a WNP whale
would be present in the vicinity of Moorings Seward or Moorings Sitka
is insignificant and discountable, and WNP gray whales are omitted from
further analysis. Sitka Sound is within a gray whale migratory
Biologically Important Area (BIA) (March-May; November-January) and a
feeding BIA (March-June)(Wild et al., 2023).
Fin whale--The fin whale is widely distributed in all the world's
oceans (Gambell, 1985), but typically occurs in coastal, shelf, and
oceanic waters in temperate and polar regions from 20-70 degrees north
and south of the Equator. Stafford et al. (2009) noted that sea-surface
temperature is a suitable predictor for fin whale call detections in
the North Pacific. Fin whales appear to have complex seasonal movements
and are seasonal migrants; they mate and calve in temperate waters
during the winter and migrate to feed at northern latitudes during the
summer (Gambell, 1985). The North Pacific population summers from the
Chukchi Sea to California and winters from California southwards
(Gambell, 1985). Fin whales are generally solitary but can also occur
in groups of two to seven individuals.
Humpback whale--Humpback whales are the most commonly observed
baleen whale in Alaska and have been observed in Southeast Alaska in
all months of the year (Baker et al., 1986). They undergo seasonal
migrations in Alaska from spring until fall with other whale species
present. There are two potential stocks of humpback whales that may
occur in the project area: the Hawai'i stock and the Mexico-North
Pacific stock (ESA-threatened). The Hawai'i stock consists of the
Southeast Alaska/Northern British Columbia demographically independent
population (DIP) and the North Pacific unit. The Southeast Alaska/
Northern British Columbia DIP spends the winter months offshore of
Hawai'i and the summer months in Southeast Alaska and Northern British
Columbia (Wade et al., 2021). The North Pacific unit migrates between
Russia and western and Central Alaska to Hawai'i. The Mexico-North
Pacific stock is likely made up of multiple DIPs, though there is
insufficient data to delineate or assess DIPs at this time, and spend
winter months off Mexico and the Revillagigedo Islands, while spending
summer months primarily in Alaska (Martien et al., 2021). Moorings
Sitka is within a seasonal humpback whale feeding BIAs (March-May,
September-December)(Wild et al., 2023).
Minke whale--Minke whales are found throughout the northern
hemisphere in polar, temperate, and tropical waters. The International
Whaling Commission has identified three minke whale stocks in the North
Pacific: one near the Sea of Japan, a second in the rest of the western
Pacific (west of 180 degrees W), and a third less concentrated stock
throughout the eastern Pacific. NMFS further splits this third stock
between Alaska whales and resident whales of California, Oregon, and
Washington (Muto et al., 2018). Minke whales are found in all Alaska
waters, however no population estimates are currently available for the
Alaska stock.
Minke whales are generally found in shallow, coastal waters within
200 m (656 ft) of shore (Zerbini et al., 2006). Dedicated surveys for
cetaceans in southeast Alaska found that minke whales were scattered
throughout inland waters from Glacier Bay and Icy Strait to Clarence
Strait, with small concentrations near the entrance of Glacier Bay.
Surveys took place in spring, summer, and fall, and minke whales were
present in low numbers in all seasons and years (Dahlheim et al.,
2009). Additionally, minke whales were observed during the Biorka
Island Dock Replacement Project at the mouth of Sitka Sound (Turnagain
Marine Construction, 2018).
Killer whale--Killer whales have been observed in all oceans, but
the highest densities occur in colder, more productive waters found at
high latitudes. Killer whales occur along the entire coast of Alaska
(Consiglieri et al., 1982), inland waterways of British Columbia and
Washington (Bigg et al., 1990), and along the outer coasts of
Washington, Oregon, and California (Forney and Barlow, 1998). Transient
killer whales hunt and feed primarily on marine mammals, including
harbor seals, Dall's porpoises, harbor porpoises, and sea lions.
Resident killer whale populations in the eastern North Pacific feed
mainly on salmonids, showing a
[[Page 60366]]
strong preference for Chinook salmon (Oncorhynchus tshawytscha) (Muto
et al., 2020). Both resident and transient killer whales were observed
in southeast Alaska during all seasons during surveys between 1991 and
2007, in a variety of habitats and in all major waterways, including
Lynn Canal, Icy Strait, Stephens Passage, Frederick Sound, and upper
Chatham Strait (Dahlheim et al., 2009). There does not appear to be
strong seasonal variation in abundance or distribution of killer
whales, but Dahlheim et al. (2009) observed substantial variability
across different years.
Eight stocks of killer whales are recognized within the Pacific
U.S. Exclusive Economic Zone (Young et al., 2023). Of those, five
stocks may be present in the project areas: Alaska Resident stock; AT1
Transient stock; Gulf of Alaska, Aleutian Islands, and Bering Sea
Transient stock; Northern Resident stock; and West Coast Transient
stock. The AT1 Transient stock is small and unlikely to occur in the
proposed project area at Moorings Seward during the 22 days of proposed
in-water work; only the Alaska Resident and Gulf of Alaska, Aleutian
Islands, and Bering Sea Transient stocks are expected at Moorings
Seward. At Moorings Sitka, the four stocks likely to be present are:
Alaska Resident stock; Gulf of Alaska, Aleutian Islands, and Bering Sea
Transient stock; Northern Resident stock; and West Coast Transient
stock.
Pacific white-sided dolphin--The Pacific white-sided dolphin is
found in temperate waters of the North Pacific from the southern Gulf
of California to Alaska. Across the North Pacific, it appears to occur
between 33 and 47 degrees N (Young et al., 2023; Waite and Shelden,
2018). In the eastern north Pacific Ocean, the Pacific white-sided
dolphin is one of the most common cetacean species, occurring primarily
in shelf and slope waters (Green et al., 1993). During winter, this
species is most abundant in California slope and offshore areas, and as
northern waters begin to warm in the spring, individuals move north to
slope and offshore waters off Oregon and Washington (Green et al.,
1993; Barlow, 2003).
Dall's porpoise--Dall's porpoise is found in temperate to subarctic
waters of the North Pacific and adjacent seas. It is widely distributed
across the North Pacific over the continental shelf and slope waters,
and over deep (greater than 2,500 m) oceanic waters (Friday et al.,
2012; Friday et al., 2013). It may be the most abundant small cetacean
in the North Pacific Ocean, and its abundance changes seasonally,
likely in relation to water temperature.
Harbor porpoise--The harbor porpoise is common in coastal waters.
Individuals frequently occur in coastal waters of southeast Alaska and
are observed most frequently in waters less than 107 m deep (Dahlheim
et al., 2009). There are six harbor porpoise stocks in Alaska: the
Bering Sea stock occurs throughout the Aleutian Islands and all waters
north of Unimak Pass; the Gulf of Alaska stock occurs from Cape
Suckling to Unimak Pass; the Northern Southeast Alaska Inland Waters
stock includes Cross Sound, Glacier Bay, Icy Strait, Chatham Strait,
Frederick Sound, Stephens Passage, Lynn Canal, and adjacent inlets; the
Southern Southeast Alaska Inland Waters stock encompasses Sumner
Strait, including areas around Wrangell and Zarembo Islands, Clarence
Strait, and adjacent inlets and channels within the inland waters of
Southeast Alaska north-northeast of Dixon Entrance; and the Yakutat/
Southeast Alaska Offshore Waters stock includes offshore habitats in
the Gulf of Alaska west of the Southeast Alaska inland waters and the
areas around Yakutat Bay (Young et al., 2023). Only the Yakutat/
Southeast Alaska Offshore Waters stock and the Gulf of Alaska stocks
are expected in the proposed project areas. The Yakutat/Southeast
Alaska Offshore Waters stock's range includes Moorings Sitka, while the
Gulf of Alaska stock range includes Moorings Seward.
Northern fur seal--The northern fur seal is endemic to the North
Pacific Ocean and occurs from southern California to the Bering Sea,
Sea of Okhotsk, and Sea of Japan. The worldwide population of northern
fur seals has declined substantially from 1.8 million animals in the
1950s due to large-scale fur seal harvests on the Pribilof Islands to
supply the fur trade (Muto et al., 2020). Two stocks are recognized in
U.S. waters: The Eastern Pacific and the California stocks. The Eastern
Pacific stock ranges from southern California during winter to the
Pribilof Islands and Bogoslof Island in the Bering Sea during summer
(Muto et al., 2020; Carretta et al., 2020). The northern fur seal
population appears to be greatly affected by El Ni[ntilde]o events and
most northern fur seals are highly migratory. The northern fur seal
spends approximately 90 percent of its time at sea, typically in areas
of upwelling along the continental slopes and over seamounts. The
remainder of its life is spent on or near rookery islands or haulouts.
During the breeding season, most of the world's population of northern
fur seals occurs on the Pribilof and Bogoslof Islands, with the main
breeding season occurring in July (Gentry, 2009).
Steller sea lion--The Steller sea lion's range extends from
northern Japan to California, with areas of abundance in the Gulf of
Alaska and Aleutian Islands (Muto et al., 2020). In 1997, based on
demographic and genetic dissimilarities, NMFS identified two distinct
population segments (DPSs) of Steller sea lions under the ESA: a
western DPS (Western stock) and an eastern DPS (Eastern stock). The
western DPS breeds on rookeries located west of 144 degrees W in Alaska
and Russia, whereas the eastern DPS breeds on rookeries in southeast
Alaska through California. Movement occurs between the western and
eastern DPSs of Steller sea lions, and increasing numbers of
individuals from the western DPS have been seen in southeast Alaska in
recent years (Muto et al., 2020; Fritz et al., 2016). This DPS-exchange
is especially evident in the outer southeast coast of Alaska, including
Sitka Sound. Hastings et al. (2020) indicates that the Eastern stock is
increasing while the Western stock is decreasing, influencing mixing of
both populations at new rookeries in northern southeast Alaska.
Steller sea lion critical habitat has been defined in Alaska at
major haulouts and major rookeries (50 CFR 226.202) but the project
action areas do not overlap with this critical habitat. Designated
critical habitat for the Western DPS of Steller sea lions includes two
major haulouts south of Moorings Seward at the mouth of Resurrection
Bay, one on Resurrection Peninsula and the other at Hive Island.
Harbor seal--Harbor seals are common in the coastal and inside
waters of the project areas. Harbor seals in Alaska are typically non-
migratory with local movements attributed to factors such as prey
availability, weather, and reproduction (Scheffer and Slipp, 1944;
Bigg, 1969; Hastings et al., 2004). Harbor seals haul out of the water
periodically to rest, give birth, and nurse their pups.
There are 12 stocks of harbor seals in Alaska, two of which occur
in the project areas: (1) the Prince William Sound stock ranges from
Elizabeth Island off the southwest tip of the Kenai Peninsula to Cape
Fairweather, including Moorings Seward; and (2) the Sitka/Chatham
Strait stock ranges from Cape Bingham south to Cape Ommaney, extending
inland to Table Bay on the west side of Kuiu Island and north through
Chatham Strait to Cube Point off the west coast of Admiralty Island,
and as far east as Cape Bendel on the
[[Page 60367]]
northeast tip of Kupreanof Island, which includes Moorings Sitka.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
(2007, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in table 6.
Table 6--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans (dolphins, 150 Hz to 160 kHz.
toothed whales, beaked whales, bottlenose
whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus cruciger
& L. australis).
Phocid pinnipeds (PW) (underwater) (true 50 Hz to 86 kHz.
seals).
Otariid pinnipeds (OW) (underwater) (sea 60 Hz to 39 kHz.
lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on approximately 65 dB threshold from
normalized composite audiogram, with the exception for lower limits
for LF cetaceans (Southall et al., 2007) and PW pinniped
(approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al.,
2013). This division between phocid and otariid pinnipeds is now
reflected in the updated hearing groups proposed in Southall et al.
(2019).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
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.
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far (ANSI, 1995). The sound level of an area is
defined by the total acoustical energy being generated by known and
unknown sources. These sources may include physical (e.g., waves, wind,
precipitation, earthquakes, ice, atmospheric sound), biological (e.g.,
sounds produced by marine mammals, fish, and invertebrates), and
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activities may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
In-water construction activities associated with the project would
include impact pile driving, vibratory pile driving, DTH, pile cutting,
and diamond wire sawing. 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 (ANSI, 1986; NIOSH, 1998; NMFS, 2018). Non-impulsive
sounds (e.g., aircraft, machinery operations such as drilling or
dredging, vibratory pile driving, pile cutting, diamond wire sawing,
and active sonar systems) can be broadband, narrowband, or tonal, brief
or prolonged (continuous or intermittent), and typically do not have
the high peak sound pressure with raid rise/decay time that impulsive
sounds do (ANSI, 1986; 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
[[Page 60368]]
to hearing (e.g., Ward, 1997; Southall et al., 2007).
Three types of hammers would be used on this project: impact,
vibratory, and DTH. Impact hammers operate by repeatedly dropping a
heavy piston onto a pile to drive the pile into the substrate. Sound
generated by impact hammers is characterized by rapid rise times and
high peak levels, a potentially injurious combination (Hastings and
Popper, 2005b). 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 10-20 dB lower than SPLs generated during impact pile driving
of the same-sized pile (Oestman et al., 2009). Rise time is slower,
reducing the probability and severity of injury, and sound energy is
distributed over a greater amount of time (Nedwell and Edwards, 2002;
Carlson et al., 2005).
A DTH hammer is essentially a drill bit that drills through the
bedrock using a rotating function like a normal drill, in concert with
a hammering mechanism operated by a pneumatic (or sometimes hydraulic)
component integrated into the DTH hammer to increase speed of progress
through the substrate (i.e., it is similar to a ``hammer drill'' hand
tool). The sounds produced by the DTH method contain both a continuous
non-impulsive component from the drilling action and an impulsive
component from the hammering effect. Therefore, we treat DTH systems as
both impulsive and non-impulsive sound source types simultaneously.
The likely or possible impacts of the USCG's proposed activity on
marine mammals involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of the equipment and personnel; however, any impacts to marine
mammals are expected to primarily be acoustic in nature. Acoustic
stressors include effects of heavy equipment operation during pile
driving activities.
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from DTH and pile driving and removal is the means by which
marine mammals may be harassed from the USCG's specified activity. In
general, animals exposed to natural or anthropogenic sound may
experience behavioral, physiological, and/or physical effects, ranging
in magnitude from none to severe (Southall et al., 2007). In general,
exposure to pile driving 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, an
auditory threshold shift (TS). Exposure to anthropogenic noise can also
lead to non-observable physiological responses such an increase in
stress hormones. Additional noise in a marine mammal's habitat can mask
acoustic cues used by marine mammals to carry out daily functions such
as communication and predator and prey detection. The effects of pile
driving noise on marine mammals are dependent on several factors,
including, but not limited to, sound type (e.g., impulsive versus non-
impulsive), the species, age and sex class (e.g., adult male versus
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., 2004; Southall et al.,
2007). Here we discuss physical auditory effects (i.e., TS) followed by
behavioral effects and potential impacts on habitat.
NMFS defines a noise-induced TS as a change, usually an increase,
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS, 2018). The amount of TS is customarily expressed in dB and
TS can be permanent or temporary. As described in NMFS (2018), 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) (Kastelein et al.,
2014), and the overlap between the animal and the source (e.g.,
spatial, temporal, and spectral).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). Available data
from humans and other terrestrial mammals indicate that a 40 dB TS
approximates PTS onset (see Ward et al., 1958; Ward et al., 1959; Ward,
1960; Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; Henderson
et al., 2008). PTS levels for marine mammals are estimates as, with the
exception of a single study unintentionally inducing PTS in a harbor
seal (e.g., Kastak et al., 2008), there are no empirical data measuring
PTS in marine mammals largely due to the fact that, for various ethical
reasons, experiments involving anthropogenic noise exposure at levels
inducing PTS are not typically pursued or authorized (NMFS, 2018).
Temporary Threshold Shift (TTS)--TTS is a temporary, reversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS, 2018). Based on data from cetacean TTS
measurements (see Southall et al., 2007), a TTS of 6 dB is considered
the minimum TS clearly larger than any day-to-day or session-to-session
variation in a subject's normal hearing ability (Finneran et al., 2000;
Schlundt 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).
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
[[Page 60369]]
some degree, though likely not without cost.
Many studies have examined noise-induced hearing loss in marine
mammals (see Finneran, 2015; Southall et al., 2019 for summaries). TTS
is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter et al., 1966). While experiencing TTS, the
hearing threshold rises, and a sound must be at a higher level in order
to be heard. In terrestrial and marine mammals, TTS can last from
minutes or hours to days (in cases of strong TTS). In many cases,
hearing sensitivity recovers rapidly after exposure to the sound ends.
For cetaceans, published data on the onset of TTS are limited to
captive bottlenose dolphin (Tursiops truncatus), beluga whale
(Delphinapterus leucas), harbor porpoise, and Yangtze finless porpoise
(Neophocoena asiaeorientalis) (Southall et al., 2019). For pinnipeds in
water, measurements of TTS are limited to harbor seals, elephant seals
(Mirounga angustirostris), bearded seals (Erignathus barbatus), and
California sea lions (Zalophus californianus) (Kastak et al., 1999;
Kastak et al., 2008; Kastelein et al., 2020b; Reichmuth et al., 2013;
Sills et al., 2020). TTS was not observed in spotted (Phoca largha) and
ringed (Pusa hispida) seals exposed to single airgun impulse sounds at
levels matching previous predictions of TTS onset (Reichmuth et al.,
2016). These studies examine hearing thresholds measured in marine
mammals before and after exposure to intense or long-duration sound
exposure. The difference between the pre-exposure and post-exposure
thresholds can be used to determine the amount of threshold shift at
various post-exposure times.
The amount and onset of TTS depends on the exposure frequency.
Sounds at low frequencies, well below the region of best sensitivity
for a species or hearing group, are less hazardous than those at higher
frequencies, near the region of best sensitivity (Finneran and
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are
higher compared to those in the region of best sensitivity (i.e., a low
frequency noise would need to be louder to cause TTS onset when TTS
exposure level is higher), as shown for harbor porpoises and harbor
seals (Kastelein et al., 2019a; Kastelein et al., 2019b; Kastelein et
al., 2020a; Kastelein et al., 2020b). Note that in general, harbor
seals and harbor porpoises have a lower TTS onset than other measured
pinniped or cetacean species (Finneran, 2015). In addition, TTS can
accumulate across multiple exposures but the resulting TTS will be less
than the TTS from a single, continuous exposure with the same SEL
(Mooney et al., 2009; Finneran et al., 2010; Kastelein et al., 2014;
Kastelein et al., 2015). This means that TTS predictions based on the
total SEL<INF>cum</INF> will overestimate the amount of TTS from
intermittent exposures, such as sonars and impulsive sources.
Nachtigall et al. (2018) describe measurements of hearing sensitivity
of multiple odontocete species (bottlenose dolphin, harbor porpoise,
beluga whale, and false killer whale (Pseudorca crassidens)) when a
relatively loud sound was preceded by a warning sound. These captive
animals were shown to reduce hearing sensitivity when warned of an
impending intense sound. Based on these experimental observations of
captive animals, the authors suggest that wild animals may dampen their
hearing during prolonged exposures or if conditioned to anticipate
intense sounds. Another study showed that echolocating animals
(including odontocetes) might have anatomical specializations that
might allow for conditioned hearing reduction and filtering of low-
frequency ambient noise, including increased stiffness and control of
middle ear structures and placement of inner ear structures (Ketten et
al., 2021). Data available on noise-induced hearing loss for mysticetes
are currently lacking (NMFS, 2018). Additionally, the existing marine
mammal TTS data come from a limited number of individuals within these
species.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals and there is no PTS data for cetaceans, but such
relationships are assumed to be similar to those in humans and other
terrestrial mammals. PTS typically occurs at exposure levels at least
several decibels above that inducing mild TTS (e.g., a 40-dB threshold
shift approximates PTS onset (Kryter et al., 1966; Miller, 1974), while
a 6-dB threshold shift approximates TTS onset (Southall et al., 2007;
Southall et al., 2019). Based on data from terrestrial mammals, a
precautionary assumption is that the PTS thresholds for impulsive
sounds (such as impact pile driving pulses as received close to the
source) are at least 6 dB higher than the TTS threshold on a peak-
pressure basis and PTS cumulative sound exposure level thresholds are
15 to 20 dB higher than TTS cumulative sound exposure level thresholds
(Southall et al., 2007; Southall et al., 2019). Given the higher level
of sound or longer exposure duration necessary to cause PTS as compared
with TTS, it is considerably less likely that PTS could occur.
Activities for this project include impact and vibratory pile
driving and removal. Installing piles requires a combination of impact
pile driving, vibratory pile driving, and DTH. For the proposed
project, these activities would not occur at the same time and there
would likely be pauses in activities producing the sound during each
day. Given these pauses and that many marine mammals are likely moving
through the project areas and not remaining for extended periods of
time, the potential for TS declines.
Behavioral Harassment--Exposure to noise from pile driving and
drilling also has the potential to behaviorally disturb marine mammals.
Generally speaking, NMFS considers a behavioral disturbance that rises
to the level of harassment under the MMPA a non-minor response--in
other words, not every response qualifies as behavioral disturbance,
and for responses that do, those of a higher level, or accrued across a
longer duration, have the potential to affect foraging, reproduction,
or survival. Behavioral disturbance may include a variety of effects,
including subtle changes in behavior (e.g., minor or brief avoidance of
an area or changes in vocalizations), more conspicuous changes in
similar behavioral activities, and more sustained and/or potentially
severe reactions, such as displacement from or abandonment of high-
quality habitat. Behavioral responses may include changing durations of
surfacing and dives, changing direction and/or speed; reducing/
increasing vocal activities; changing/cessation of certain behavioral
activities (such as socializing or feeding); eliciting a visible
startle response or aggressive behavior (such as tail/fin slapping or
jaw clapping); avoidance of areas where sound sources are located.
Pinnipeds may increase their haul out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006). Behavioral responses to sound
are highly variable and context-specific and any reactions depend on
numerous intrinsic and extrinsic factors (e.g., species, state of
maturity, experience, current activity, reproductive state, auditory
sensitivity, time of day), as well as the interplay between factors
(e.g., Richardson et al., 1995; Wartzok et al., 2004; Southall et al.,
2007; Southall et al., 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
[[Page 60370]]
associated with the sound source (e.g., whether it is moving or
stationary, number of sources, distance from the source). In general,
pinnipeds seem more tolerant of, or at least habituate more quickly to,
potentially disturbing underwater sound than do cetaceans, and
generally seem to be less responsive to exposure to industrial sound
than most cetaceans. Please see Appendices B and C of Southall et al.
(2007) and Gomez et al. (2016) for reviews of studies involving marine
mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2004). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure.
As noted above, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; Wartzok et al., 2004; NRC, 2005). Controlled experiments with
captive marine mammals have showed pronounced behavioral reactions,
including avoidance of loud sound sources (Ridgway et al., 1997;
Finneran et al., 2003). Observed responses of wild marine mammals to
loud pulsed sound sources (e.g., seismic airguns) have been varied but
often consist of avoidance behavior or other behavioral changes
(Richardson et al., 1995; Morton and Symonds, 2002; Nowacek et al.,
2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Nowacek et al., 2004; Goldbogen et al., 2013a;
Goldbogen et al., 2013b). Variations in dive behavior may reflect
interruptions in biologically significant activities (e.g., foraging)
or they may be of little biological significance. The impact of an
alteration to dive behavior resulting from an acoustic exposure depends
on what the animal is doing at the time of the exposure and the type
and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al.,
2007). A determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
Variations in respiration naturally vary with different behaviors
and alterations to breathing rate as a function of acoustic exposure
can be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response. Various studies have shown that respiration rates may
either be unaffected or could increase, depending on the species and
signal characteristics, again highlighting the importance in
understanding species differences in the 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).
For example, harbor porpoise' respiration rate increased in response to
pile driving sounds at and above a received broadband SPL of 136 dB
(zero-peak SPL: 151 dB re 1 [mu]Pa; SEL of a single strike: 127 dB re 1
[mu]Pa\2\-s) (Kastelein et al., 2013).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003) or vocalizations (Foote et al., 2004),
respectively, while North Atlantic right whales (Eubalaena glacialis)
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007). In some cases, animals may cease sound
production during production of aversive signals (Bowles et al., 1994).
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 may be short-
term, with animals returning to the area once the noise has ceased
(e.g., Bowles et al., 1994; Morton and Symonds, 2002). 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).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996; Bowers et al., 2018).
[[Page 60371]]
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). However, it should be noted that response to a
perceived predator does not necessarily invoke flight (Ford and Reeves,
2008), and whether individuals are solitary or in groups may influence
the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fishes and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Purser and Radford, 2011; Fritz et al., 2002). 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., Daan et
al., 1996; Bradshaw et al., 1998). However, Ridgway et al. (2006)
reported that increased vigilance in bottlenose dolphins exposed to
sound over a 5-day period did not cause any sleep deprivation or stress
effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than 1 day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive (i.e., meaningful) behavioral reactions and multi-day
anthropogenic activities. For example, just because an activity lasts
for multiple days does not necessarily mean that individual animals are
either exposed to activity-related stressors for multiple days or,
further, exposed in a manner resulting in sustained multi-day
substantive behavioral responses.
In 2016, the Alaska Department of Transportation and Public
Facilities documented observations of marine mammals during
construction activities (i.e., pile driving and DTH) at the Kodiak
Ferry Dock (see 80 FR 60636, October 7, 2015). In the marine mammal
monitoring report for that project, 1,281 Steller sea lions were
observed within the estimated Level B harassment zone during pile
driving or drilling. Of these, 19 individuals demonstrated an alert
behavior, seven were fleeing, and 19 swam away from the project site.
All other animals (98 percent) were engaged in activities such as
milling, foraging, or fighting and did not change their behavior. In
addition, two sea lions approached within 20 m of active vibratory pile
driving activities. Three harbor seals were observed within the
disturbance zone during pile driving activities; none of them displayed
disturbance behaviors. Fifteen killer whales and three harbor porpoises
were also observed within the estimated Level B harassment zone during
pile driving. The killer whales were travelling or milling while all
harbor porpoises were travelling. No signs of disturbance were noted
for either of these species. Given the similarities in activities and
habitat and the fact the same species are involved, we expect similar
behavioral responses of marine mammals to the USCG's specified
activity. That is, disturbance, if any, is likely to be temporary and
localized (e.g., small area movements). Monitoring reports from other
recent pile driving and DTH projects in Alaska have observed similar
behaviors (e.g., the Biorka Island Dock Replacement Project <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-faa-biorka-island-dock-replacement-project-sitka-ak">https://www.fisheries.noaa.gov/action/incidental-take-authorization-faa-biorka-island-dock-replacement-project-sitka-ak</a>).
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., Selye, 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 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 vessel traffic in the Bay of Fundy
was associated with decreased stress in North Atlantic right whales
(Eubalaena glacialis). These and other studies lead to a reasonable
expectation that some marine mammals will experience physiological
stress responses upon exposure to acoustic stressors and that 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 the proposed project based on observations of marine mammals during
previous, similar projects in the region.
Auditory Masking--Since many marine mammals rely on sound to find
prey, moderate social interactions, and facilitate mating (Tyack,
2008), noise from anthropogenic sound sources can interfere with these
functions, but only if the noise spectrum overlaps with the hearing
sensitivity of the receiving
[[Page 60372]]
marine mammal (Southall et al., 2007; Clark et al., 2009; Hatch et al.,
2012). Chronic exposure to excessive, though not high-intensity, noise
could cause masking at particular frequencies for marine mammals that
utilize sound for vital biological functions (Clark et al., 2009).
Acoustic masking is when other noises such as from human sources
interfere with an animal's ability to detect, recognize, or
discriminate between acoustic signals of interest (e.g., those used for
intraspecific communication and social interactions, prey detection,
predator avoidance, navigation) (Richardson et al., 1995; Erbe et al.,
2016). Therefore, under certain circumstances, marine mammals whose
acoustical sensors or environment are being severely masked could also
be impaired from maximizing their performance fitness in survival and
reproduction. The ability of a noise source to mask biologically
important sounds depends on the characteristics of both the noise
source and the signal of interest (e.g., signal-to-noise ratio,
temporal variability, direction), in relation to each other and to an
animal's hearing abilities (e.g., sensitivity, frequency range,
critical ratios, frequency discrimination, directional discrimination,
age or TTS hearing loss), and existing ambient noise and propagation
conditions (Hotchkin and Parks, 2013).
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is human-made, it may be considered
harassment when disrupting or altering critical behaviors. It is
important to distinguish TTS and PTS, which persist after the sound
exposure, from masking, which occurs during the sound exposure. Because
masking (without resulting in TS) is not associated with abnormal
physiological function, it is not considered a physiological effect,
but rather a potential behavioral effect (though not necessarily one
that would be associated with harassment).
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al., 2000;
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2010; Holt
et al., 2009). Masking can be reduced in situations where the signal
and noise come from different directions (Richardson et al., 1995),
through amplitude modulation of the signal, or through other
compensatory behaviors (Hotchkin and Parks, 2013). Masking can be
tested directly in captive species (e.g., Erbe, 2008), but in wild
populations it must be either modeled or inferred from evidence of
masking compensation. There are few studies addressing real-world
masking sounds likely to be experienced by marine mammals in the wild
(e.g., Branstetter et al., 2013).
Marine mammals at or near the proposed project sites may be exposed
to anthropogenic noise which may be a source of masking. Vocalization
changes may result from a need to compete with an increase in
background noise and include increasing the source level, modifying the
frequency, increasing the call repetition rate of vocalizations, or
ceasing to vocalize in the presence of increased noise (Hotchkin and
Parks, 2013). For example, in response to loud noise, beluga whales may
shift the frequency of their echolocation clicks to prevent masking by
anthropogenic noise (Eickmeier and Vallarta, 2023).
Masking is more likely to occur in the presence of broadband,
relatively continuous noise sources such as vibratory pile driving.
Energy distribution of pile driving covers a broad frequency spectrum,
and sound from pile driving would be within the audible range of
pinnipeds and cetaceans present in the proposed action area. While some
construction during the USCG's activities may mask some acoustic
signals that are relevant to the daily behavior of marine mammals, the
short-term duration and limited areas affected make it very unlikely
that the fitness of individual marine mammals would be impacted.
Airborne Acoustic Effects--Airborne noise would primarily be an
issue for pinnipeds that are swimming or hauled out near the project
areas 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. Thus, the behavioral
harassment of these animals is already accounted for in estimates of
potential take. Therefore, we do not believe that authorization of
incidental take resulting from airborne sound for pinnipeds is
warranted, and airborne sound is not discussed further. Cetaceans are
not expected to be exposed to airborne sounds that would result in
harassment as defined under the MMPA.
Marine Mammal Habitat Effects
The USCG's proposed construction activities could have localized,
temporary impacts on marine mammal habitat, including prey, by
increasing in-water SPLs and slightly decreasing water quality.
Increased noise levels may affect acoustic habitat (see Masking) and
adversely affect marine mammal prey in the vicinity of the project area
(see discussion below). During DTH, impact, and vibratory pile driving,
elevated levels of underwater noise would ensonify the project area
where both fish and mammals occur and could affect foraging success.
Additionally, marine mammals may avoid the area during construction;
however, displacement due to noise is expected to be temporary and is
not expected to result in long-term effects to the individuals or
populations. In-water pile driving activities would also cause short-
term effects on water quality due to increased turbidity. Temporary and
localized increase in turbidity near the seafloor would occur in the
immediate area surrounding the area where piles are installed or
removed. In general, turbidity associated with pile installation is
localized to about a 25 ft (7.6 m) radius around the pile (Everitt et
al., 1980). The sediments of the project site would settle out rapidly
when disturbed. Cetaceans are not expected to be close enough to the
pile driving areas to experience effects of turbidity, and any
pinnipeds could avoid localized areas of turbidity. The USCG would
employ other standard construction best management practices (see
section 11 in the USCG's application), thereby reducing any impacts.
Therefore, we expect the
[[Page 60373]]
impact from increased turbidity levels to be discountable to marine
mammals and do not discuss it further.
In-Water Construction Effects on Potential Foraging Habitat--The
proposed activities would not result in permanent impacts to habitats
used directly by marine mammals and no increases in vessel traffic are
expected in either location as a result of the specified activities.
The areas likely impacted by the proposed action are relatively small
compared to the total available habitat in the Gulf of Alaska and
Southeast Alaska. The proposed project areas are highly influenced by
anthropogenic activities and provides limited foraging habitat for
marine mammals. The total seafloor area affected by piling activities
is small compared to the vast foraging areas available to marine
mammals at either location. At best, the areas impacted provide
marginal foraging habitat for marine mammals and fishes. Furthermore,
pile driving at the project locations would not obstruct movements or
migration of marine mammals.
In-Water Construction Effects on Potential Prey--Sound may affect
marine mammals through impacts on the abundance, behavior, or
distribution of prey species (e.g., crustaceans, cephalopods, fish,
zooplankton, and other marine mammals). Marine mammal prey varies by
species, season, and location. Here, we describe studies regarding the
effects of noise on known marine mammal prey.
Construction activities would produce continuous, non-impulsive
(i.e., vibratory pile driving, DTH) and intermittent impulsive (i.e.,
impact pile driving, DTH) sounds. Fish utilize the soundscape and
components of sound in their environment to perform important functions
such as foraging, predator avoidance, mating, and spawning (Zelick et
al., 1999; Fay, 2009). Depending on their hearing anatomy and
peripheral sensory structures, which vary among species, fishes hear
sounds using pressure and particle motion sensitivity capabilities and
detect the motion of surrounding water (Fay et al., 2008). The
potential effects of noise on fishes depends on the overlapping
frequency range, distance from the sound source, water depth of
exposure, and species-specific hearing sensitivity, anatomy, and
physiology. Key impacts to fishes may include behavioral responses,
hearing damage, barotrauma (pressure-related injuries), and mortality.
Fish react to sounds which are especially strong and/or
intermittent low-frequency sounds, and behavioral responses such as
flight or avoidance are the most likely effects. Short duration, sharp
sounds can cause overt or subtle changes in fish behavior and local
distribution. The reaction of fish to noise depends on the
physiological state of the fish, past exposures, motivation (e.g.,
feeding, spawning, migration), and other environmental factors.
Hastings and Popper (2005a) 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 of
which are based on studies in support of large, multiyear bridge
construction projects (e.g., Scholik and Yan, 2001; Popper and
Hastings, 2009). Many 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.,
Pearson et al., 1992; Skalski et al., 1992; Santulli et al., 1999;
Fewtrell and McCauley, 2012; Paxton et al., 2017). In response to pile
driving, Pacific sardines (Sardinops sagax) and northern anchovies
(Engraulis mordax) may exhibit an immediate startle response to
individual strikes but return to ``normal'' pre-strike behavior
following the conclusion of pile driving with no evidence of injury as
a result (see NAVFAC, 2014). However, some studies have shown no or
slight reaction to impulse sounds (e.g., Wardle et al., 2001; Popper et
al., 2005; Jorgenson and Gyselman, 2009; Pe[ntilde]a et al., 2013).
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. (2012b) showed that a TTS of 4-6 dB was recoverable within 24 hours
for one species. Impacts would be most severe when the individual fish
is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012a; Casper et al., 2013) and the greatest
potential effect on fish during the proposed project would occur during
impact pile driving, if it is required. However, the duration of impact
pile driving would be limited to a contingency in the event that
vibratory driving does not satisfactorily install the pile depending on
observed soil resistance. In-water construction activities would only
occur during daylight hours allowing fish to forage and transit the
project area at night. Vibratory pile driving may elicit behavioral
reactions from fish such as temporary avoidance of the area but is
unlikely to cause injuries to fish or have persistent effects on local
fish populations. In addition, it should be noted that the area in
question is low-quality habitat since it is already developed and
experiences anthropogenic noise from vessel traffic.
The most likely impact to fishes from pile driving and DTH
activities in the project areas would be temporary behavioral avoidance
of the area. The duration of fish avoidance of the area after pile
driving stops is unknown but a rapid return to normal recruitment,
distribution, and behavior is anticipated. There are times of known
seasonal marine mammal foraging when fish are aggregating but the
impacted areas are small portions of the total foraging habitats
available in the regions. In general, impacts to marine mammal prey
species are expected to be minor and temporary. Further, it is
anticipated that preparation activities for pile driving and DTH (i.e.,
positioning of the hammer) and upon initial startup of devices would
cause fish to move away from the affected area where injuries may
occur. Therefore, relatively small portions of the proposed project
area would be affected for short periods of time, and the potential for
effects on fish to occur would be temporary and limited to the duration
of sound[hyphen]generating activities.
Construction activities, in the form of increased turbidity, also
have the potential to adversely affect forage fish in the project area.
Pacific herring (Clupea pallasii) is a primary prey species of Steller
sea lions, humpback whales, and many other marine mammal species that
occur in the project areas. As discussed earlier, increased turbidity
is expected to occur in the immediate vicinity (approximately 25 ft
(7.6 m) or less) of construction activities (Everitt et al., 1980).
However, suspended sediments and particulates are expected to dissipate
quickly within a single tidal cycle. Given the limited area affected
and high tidal dilution rates any effects on forage fish are expected
to be minor or negligible. In addition, best management practices would
be in effect to limit the extent of turbidity to the immediate project
areas. Finally, exposure to turbid waters from construction activities
is not expected to be different from the current exposure; fish and
marine mammals in the regions
[[Page 60374]]
are routinely exposed to substantial levels of suspended sediment from
glacial sources.
In summary, given the short daily duration of sound associated with
pile driving and DTH, and the relatively small areas being affected,
pile driving and DTH activities associated with the proposed action are
not likely to have a permanent adverse effect on any fish habitat, or
populations of fish species. Thus, we conclude that impacts of the
specified activity are not likely to have more than short-term adverse
effects on any prey habitat or populations of prey species. Further,
any impacts to marine mammal habitat are not expected to result in
significant or long-term consequences for individual marine mammals, or
to contribute to adverse impacts on their populations.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
proposed for authorization through the IHA, which will inform NMFS'
consideration of ``small numbers,'' the negligible impact
determinations, and impacts on subsistence uses.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would primarily be by Level B harassment, as use
of the acoustic sources (i.e., vibratory and impact pile driving, DTH)
has the potential to result in disruption of behavioral patterns for
individual marine mammals. There is also some potential for auditory
injury (Level A harassment) to result, primarily for high-frequency
species and phocids, because predicted auditory injury zones are large
and these species could enter the Level A harassment zones and remain
undetected for a sufficient duration to incur auditory injury due to
their small size and inconspicuous nature. Although auditory injury
could occur for low-frequency species due to large predicted auditory
injury zones associated with DTH, due to their large size, conspicuous
nature, and proposed mitigation (i.e., large shutdown zones, boat-based
protected species observers (PSOs)), it is assumed that all low-
frequency species would be visually detected and, therefore, taking by
Level A harassment would be eliminated. 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 PTS of some degree (equated to Level A
harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007; Southall et al., 2021; Ellison et
al., 2012). Based on what the available science indicates and the
practical need to use a threshold based on a metric that is both
predictable and measurable for most activities, NMFS typically uses a
generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS generally predicts that marine
mammals are likely to be behaviorally harassed in a manner considered
to be Level B harassment when exposed to underwater anthropogenic noise
above root-mean-squared pressure received levels (RMS SPL) of 120 dB
(referenced to 1 microPascal (re 1 [mu]Pa)) for continuous (e.g.,
vibratory pile driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa
for non-explosive impulsive (e.g., seismic airguns) or intermittent
(e.g., scientific sonar) sources. Generally speaking, Level B
harassment take estimates based on these behavioral harassment
thresholds are expected to include any likely takes by TTS as, in most
cases, the likelihood of TTS occurs at distances from the source less
than those at which behavioral harassment is likely. TTS of a
sufficient degree can manifest as behavioral harassment, as reduced
hearing sensitivity and the potential reduced opportunities to detect
important signals (conspecific communication, predators, prey) may
result in changes in behavior patterns that would not otherwise occur.
The USCG's proposed activity includes the use of continuous
(vibratory and DTH) and impulsive (impact driving and DTH) sources, and
therefore the 120 and 160 dB re 1 [mu]Pa (RMS) thresholds,
respectively, are applicable.
Level A Harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0)
(NMFS, 2018) identifies dual criteria to assess auditory injury (Level
A harassment) to five different marine mammal groups (based on hearing
sensitivity) as a result of exposure to noise from two different types
of sources (impulsive or non-impulsive). The USCG's proposed activity
includes the use of impulsive (impact driving and DTH) and non-
impulsive (vibratory and DTH) sources.
These thresholds are provided in table 7 below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS' 2018 Technical Guidance, which may be accessed at:
<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>.
[[Page 60375]]
Table 7--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak SPL thresholds
associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this table, thresholds are abbreviated to reflect American
National Standards Institute (ANSI) standards (ANSI, 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss (TL)
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., impact pile driving, vibratory
pile driving, vibratory pile removal, and DTH).
In order to calculate distances to the Level A harassment and Level
B harassment thresholds for the methods and piles proposed for this
project, NMFS used acoustic monitoring data from other locations to
develop source levels for the various pile types, sizes and methods
(tables 8-11). This analysis uses practical spreading loss, a standard
assumption regarding sound propagation for similar environments, to
estimate transmission of sound through water. For this analysis, the TL
factor of 15 (4.5 dB per doubling of distance) is used. A weighting
adjustment factor of 2.5 or 2, a standard default value for vibratory
pile driving and removal or impact driving and DTH respectively, were
used to calculate Level A harassment areas.
NMFS recommends treating DTH systems as both impulsive and
continuous, non-impulsive sound source types simultaneously. Thus,
impulsive thresholds are used to evaluate Level A harassment, and
continuous thresholds are used to evaluate Level B harassment. With
regards to DTH mono-hammers, NMFS recommends proxy levels for Level A
harassment based on available data regarding DTH systems of similar
sized piles and holes (Denes et al., 2019; Guan and Miner, 2020;
Heyvaert and Reyff, 2021; Reyff, 2020; Reyff and Heyvaert, 2019).
Table 8--Observed Non-Impulsive Sound Levels and Durations for In-Water Activities Likely To Occur at Moorings
Seward
----------------------------------------------------------------------------------------------------------------
Average
RMS SPL (dB re duration Piles per
In-water activity Pile size and type 1 [micro]Pa) per pile day
at 10 m (seconds)
----------------------------------------------------------------------------------------------------------------
Vibratory Pile Extraction \a\............. 14-inch steel guide pile.... 160.0 1,800 5
Vibratory Pile Settling \a\............... 30-inch concrete guide pile. 163.0 600 2
Rock socket drill \b\ (non-impulsive 30-inch concrete guide pile. 174 \c\ 10,800 2
component).
----------------------------------------------------------------------------------------------------------------
Abbreviations: dB re 1 [micro]Pa = decibels referenced to a pressure of 1 microPascal, m = meters.
\a\ NMFS 2024.
\b\ NMFS 2022.
\c\ Rock socket drilling is a DTH activity with multiple strikes per second. DTH activities produce sounds that
simultaneously contain both non-impulsive and impulsive components.
Table 9--Observed Impulsive Sound Levels and Durations for Pile Installation Activities Likely To Occur at Moorings Seward
--------------------------------------------------------------------------------------------------------------------------------------------------------
SELsingle-strike
Peak (dB re 1 RMS (dB re 1 (dB re 1 Strikes per Maximum Piles per
Installation method Pile size and type [micro]Pa) at [micro]Pa) at [micro]Pa) at 10 day strikes day
10 m 10 m m per pile
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rock socket drill \a\.................. 30-inch concrete guide 194 174 164 \c\ 216,000 108,000 2
pile.
Impact hammer proofing \b\............. 30-inch concrete guide 198 186 173 10 5 2
pile.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Abbreviations: dB re 1 [micro]Pa = decibels referenced to a pressure of 1 microPascal, m = meters.
\a\ NMFS 2022.
\b\ NMFS 2024.
\c\ Rock socket drilling is a DTH activity with multiple strikes per second. DTH activities produce sounds that simultaneously contain both non-
impulsive and impulsive components.
[[Page 60376]]
Table 10--Observed Non-Impulsive Sound Levels and Durations for In-Water Activities Likely To Occur at Moorings
Sitka
----------------------------------------------------------------------------------------------------------------
Average
RMS SPL (dB re duration Piles per
In-water activity Pile size and type 1 [micro]Pa) per pile day
at 10 m (seconds)
----------------------------------------------------------------------------------------------------------------
Vibratory Pile Extraction \a\............. 12-inch timber piles........ 162.0 1,800 5
Vibratory Pile Settling \b\............... 30-inch concrete guide and 163.0 600 2
structure pile.
Rock socket drill \c\ (non-impulsive 30-inch concrete guide and 174 10,800 2
component). structure pile.
----------------------------------------------------------------------------------------------------------------
Abbreviations: dB re 1 [micro]Pa = decibels referenced to a pressure of 1 microPascal, m = meters.
\a\ NMFS 2024.
\b\ NMFS 2022.
\c\ Rock socket drilling is a DTH activity with multiple strikes per second. DTH activities produce sounds that
simultaneously contain both non-impulsive and impulsive components.
Table 11--Observed Impulsive Sound Levels and Durations for Pile Installation Activities Likely To Occur at
Moorings Sitka
----------------------------------------------------------------------------------------------------------------
SELsingle-
Pile size and Peak (re 1 RMS (dB re 1 strike (dB re
Installation method type [micro]Pa) at [micro]Pa) at 1 [micro]Pa) Strikes per day
10 m 10 m at 10 m
----------------------------------------------------------------------------------------------------------------
Impact drive \a\............. 13-inch plastic 177 153 NA 200 (up to 100
fender pile. strikes per
pile and 2
piles per
day).
Impact drive \a\............. 14-inch timber 180 170 160 320 (up to 160
guide pile. strikes per
pile and 2
piles per
day).
Rock socket drill \b\........ 30-inch concrete 194 174 164 216,000 (up to
guide pile. 108,000
strikes per
pile and 2
piles per
day).\d\
Impact hammer proofing \c\... 30-inch concrete 198 186 173 10 (up to 5
guide pile. strikes per
pile and 2
piles per
day).
----------------------------------------------------------------------------------------------------------------
Abbreviations: dB re 1 [micro]Pa = decibels referenced to a pressure of 1 microPascal, m = meters.
\a\ Caltrans 2020.
\b\ NMFS 2022.
\c\ NMFS 2024.
\d\ Rock socket drilling is a DTH activity with multiple strikes per second. DTH activities produce sounds that
simultaneously contain both non-impulsive and impulsive components.
Level B Harassment Zones--TL is the decrease in acoustic intensity
as an acoustic pressure wave propagates out from a source. TL
parameters vary with frequency, temperature, sea conditions, current,
source and receiver depth, water depth, water chemistry, and bottom
composition and topography. The general formula for underwater TL is:
TL = B * log<INF>10</INF> (R<INF>1</INF>/R<INF>2</INF>),
Where:
TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R<INF>1</INF> = the distance of the modeled SPL from the driven
pile, and
R<INF>2</INF> = the distance from the driven pile of the initial
measurement.
The recommended TL coefficient for most nearshore environments is
the practical spreading value of 15. This value results in an expected
propagation environment that would lie between spherical and
cylindrical spreading loss conditions, which is the most appropriate
assumption for the USCG's proposed activities. The Level B harassment
zones and approximate amount of area ensonified for the proposed
underwater activities are shown in tables 12 and 13.
Level A Harassment Zones--The ensonified area associated with Level
A harassment is more technically challenging to predict due to the need
to account for a duration component. Therefore, NMFS developed an
optional User Spreadsheet tool to accompany the Technical Guidance that
can be used to relatively simply predict an isopleth distance for use
in conjunction with marine mammal density or occurrence to help predict
potential takes. We note that because of some of the assumptions
included in the methods underlying this optional tool, we anticipate
that the resulting isopleth estimates are typically going to be
overestimates of some degree, which may result in an overestimate of
potential take by Level A harassment. However, this optional tool
offers the best way to estimate isopleth distances when more
sophisticated modeling methods are not available or practical. For
stationary sources such as pile driving and DTH, the optional User
Spreadsheet tool predicts the distance at which, if a marine mammal
remained at that distance for the duration of the activity, it would be
expected to incur PTS. Inputs used in the optional User Spreadsheet
tool (e.g., number of piles per day, duration and/or strikes per pile)
are presented in tables 8-11, and the resulting estimated isopleths and
total ensonified areas are reported below in tables 12 and 13.
Table 12--Projected Distances to Level A and Level B Harassment Isopleths by Marine Mammal Hearing Group at Moorings Seward
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total
Distance to Distance to Distance to Distance to Distance to Level B ensonified
Activity Level A (m) Level A (m) Level A (m) Level A (m) Level A (m) distance area
for LF for MF for HF for PW for OW (m) (km\2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory pile extraction.................................... 10.8 1.0 16.0 6.6 0.5 4,641.6 1.94
DTH (Impulsive component) concrete........................... 1,945.5 69.2 2,317.4 1,041.2 75.8 39,810.7 * 2.26
Vibratory settling concrete.................................. 4.5 0.4 6.6 2.7 0.2 7,356.4 * 2.26
[[Page 60377]]
Impact driver proofing concrete.............................. 10.0 0.4 11.9 5.3 0.4 541.2 0.11
--------------------------------------------------------------------------------------------------------------------------------------------------------
Abbreviations: LF = low-frequency cetaceans, MF = mid-frequency cetaceans, HF = high-frequency cetaceans, PW = phocid pinnipeds in water, OW = otariid
pinnipeds in water.
* Total harassment areas are the same despite having varying radii because the maximum distance intersects with the other side of Resurrection Bay near
Seward resulting in the same areal extent.
Table 13--Projected Distances to Level A and Level B Harassment Isopleths by Marine Mammal Hearing Group at Moorings Sitka
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total
Distance to Distance to Distance to Distance to Distance to Level B ensonified
Activity Level A (m) Level A (m) Level A (m) Level A (m) Level A (m) distance area
for LF for MF for HF for PW for OW (m) (km\2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory pile extraction.................................... 14.7 1.3 21.7 6.9 0.6 6,309.6 4.17
Impact drive plastic......................................... 13.6 0.5 16.2 7.3 0.5 3.4 0.0
Impact drive timber.......................................... 13.7 0.5 16.3 7.3 0.5 46.4 0.01
DTH (Impulsive component).................................... 1,945.5 69.2 2,317.4 1,041.2 75.8 39,810.7 6.31
Vibratory settling concrete.................................. 4.5 0.4 6.6 2.7 0.2 7,356.4 4.89
Impact driver proofing concrete.............................. 10.0 0.4 11.9 5.3 0.4 541.2 0.33
--------------------------------------------------------------------------------------------------------------------------------------------------------
Abbreviations: LF = low-frequency cetaceans, MF = mid-frequency cetaceans, HF = high-frequency cetaceans, PW = phocid pinnipeds in water, OW = otariid
pinnipeds in water.
Marine Mammal Occurrence
In this section we provide information about the occurrence of
marine mammals, including density or other relevant information which
will inform the take calculations. Available information regarding
marine mammal occurrence and density in the project areas includes
monitoring data, prior incidental take authorizations, and ESA
consultations on previous projects. When local density information is
not available, data aggregated in the Navy's Marine Mammal Species
Density Database (Navy, 2019; Navy, 2020) for the Northwest or Gulf of
Alaska Testing and Training areas or nearby proxies from the monitoring
data are used; whichever gives the most precautionary take estimate was
chosen. Daily occurrence probability of each marine mammal species is
based on consultation with previous monitoring reports, local
researchers and marine professionals. Occurrence probability estimates
at Moorings Sitka are based on conservative density approximations for
each species and factor in historic data of occurrence, seasonality,
and group size in Sitka Sound and Sitka Channel. A summary of proposed
occurrence is shown in table 14. Group size is based on the best
available published research for these species and their presence in
the project areas.
Table 14--Estimated Species Occurrence or Density Values
----------------------------------------------------------------------------------------------------------------
Species Stock Moorings Seward Moorings Sitka
----------------------------------------------------------------------------------------------------------------
Steller sea lion a b................. Western................ 2 individuals/day...... 1-2 groups of 2
individuals/day of
either stock.
Steller sea lion a b................. Eastern................ 0...................... 1-2 groups of 2
individuals/day of
either stock.
Northern fur seal.................... Eastern Pacific........ 0...................... 1 individual/month.
Harbor seal.......................... Prince William Sound... 48.95 individuals/day.. 0.
Harbor seal \a\...................... Sitka/Chatham Strait... 0...................... 1-2 groups of 2.1
individuals/day.
Killer whale......................... Alaska Resident........ 1 group of 7 1 group of 6.6
individuals/week of individuals/week of
either stock. any stock.
Killer whale......................... Gulf of Alaska, 1 group of 7 1 group of 6.6
Aleutian Islands, and individuals/week of individuals/week of
Bering Sea Transient. either stock. any stock.
Killer whale......................... Northern Resident...... 0...................... 1 group of 6.6
individuals/week of
any stock.
Killer whale......................... West Coast Transient... 0...................... 1 group of 6.6
individuals/week of
any stock.
Pacific white-sided dolphin.......... North Pacific.......... 3 individuals/day...... 0.
Harbor porpoise...................... Gulf of Alaska......... 0.4547 individuals/ 0.
km\2\.
Harbor porpoise...................... Yakutat/Southeast 0...................... 1 group of 5
Alaska Offshore Waters. individuals/2 weeks.
Dall's porpoise...................... Alaska................. 0.25 individuals/day... 0.121 individuals/
km\2\.
Sperm whale.......................... North Pacific.......... 0...................... 0.002 individuals/
km\2\.
Humpback whale \c\................... Hawai[revaps]i......... 1 individual/day of 1 group of 3.4
either stock. individuals/week of
either stock.
Humpback whale \c\................... Mexico-North Pacific... 1 individual/day of 1 group of 3.4
either stock. individuals/week of
either stock.
Gray whale........................... Eastern North Pacific.. 0.0155 individuals/ 1 group of 3.5
km\2\. individuals/2 weeks.
[[Page 60378]]
Fin whale............................ Northeast Pacific...... 0.068 individuals/km\2\ 0.0001 individuals/
km\2\.
Minke whale.......................... Alaska................. 0.006 individuals/km\2\ 1 group of 3.5
individuals/2 weeks.
----------------------------------------------------------------------------------------------------------------
Note: Occurrence value presented as individuals per unit time; density value presented as individuals per square
kilometer.
\a\ Likelihood of one group per day in the Level A harassment zone and likelihood of two groups per day in the
Level B harassment zone.
\b\ Steller sea lion stock attribution is 100% Western DPS at Moorings Seward; 97.8% Eastern DPS and 2.2%
Western DPS at Moorings Sitka.
\c\ Humpback whale stock attribution is 89% Hawai[revaps]i and 11% Mexico-North Pacific at Moorings Seward; 98%
Hawai[revaps]i and 2% Mexico-North Pacific at Moorings Sitka.
Gray whale--Members of the ENP stock have a small chance to occur
at the northern end of Resurrection Bay near Moorings Seward, with an
estimated density of 0.0155 individuals/km\2\.
During 190 hours of observation from 1994 to 2002 from Sitka's
Whale Park, only three gray whales were observed (Straley et al.,
2017). However, Straley and Wild (unpublished data) note that since
2014, the number of gray whale sightings in Sitka Sound has increased
to an estimated 150-200 individuals in 2021 and 2022. Based on this and
recent monitoring data collected near Sitka, the estimated occurrence
of gray whales at Moorings Sitka is one group of 3.5 individuals every
2 weeks.
Fin whale--Fin whales have the potential to occur at both Moorings
Seward and Moorings Sitka. Based on survey data, fin whales in the
vicinity of Moorings Seward are anticipated to occur at a density of
0.068/km\2\ and fin whales in the vicinity of Moorings Sitka are
anticipated to occur at a density of 0.0001/km\2\.
Humpback whale--Humpback whales found in the project areas are
predominantly members of the Hawai[revaps]i DPS (89 percent at Moorings
Seward, 98 percent probability at Moorings Sitka), which is not listed
under the ESA. However, based on a comprehensive photo-identification
study, members of the Mexico DPS, which is listed as threatened, have a
small potential to occur in all project locations (11 percent at
Moorings Seward, 2 percent at Moorings Sitka) (Wade, 2016), and it is
estimated that one individual per day of either stock may occur at
Moorings Seward while one group of 3.5 individuals per 2 weeks of
either stock may occur at Moorings Sitka.
Minke whale--Minke whales are generally found in shallow, coastal
waters within 200 m (656 ft) of shore (Zerbini et al., 2006). Dedicated
surveys for cetaceans in southeast Alaska found that minke whales were
scattered throughout inland waters from Glacier Bay and Icy Strait to
Clarence Strait, with small concentrations near the entrance of Glacier
Bay. Surveys took place in spring, summer, and fall, and minke whales
were present in low numbers in all seasons and years (Dahlheim et al.,
2009). Additionally, minke whales were observed during the Biorka
Island Dock Replacement Project at the mouth of Sitka Sound (Turnagain
Marine Construction, 2018). Minke whale density at Moorings Seward is
estimated as 0.006 individuals/km\2\ while estimated occurrence at
Moorings Sitka is one group of 3.5 individuals every 2 weeks.
Killer whale--Killer whales occur along the entire coast of Alaska
(Braham and Dahlheim, 1982) and four stocks may be present in the
project areas as follows: (1) Alaska Resident stock--both locations;
(2) Gulf of Alaska, Aleutian Islands, and Bering Sea Transient stock--
both locations; (3) Northern Resident--Sitka only; and (4) West Coast
Transient stock--Sitka only.
The Alaska Resident stock occurs from southeast Alaska to the
Aleutian Islands and Bering Sea. The Gulf of Alaska, Aleutian Islands,
and Bering Sea Transient stock occurs from the northern British
Columbia coast to the Aleutian Islands and Bering Sea. The Northern
Resident stock occurs from Washington north through part of southeast
Alaska. The West Coast Transient stock occurs from California north
through southeast Alaska (Muto et al., 2020). One group of seven
individuals per week from either the Alaska Resident stock or the Gulf
of Alaska, Aleutian Islands, and Bering Sea Transient stock are
estimated to occur at Moorings Seward. One group of 6.6 individuals per
week from any of the four stocks are estimated to occur at Moorings
Sitka.
Pacific white-sided dolphin--Pacific white-sided dolphins are
anticipated to occur in the vicinity of Moorings Seward only. Previous
construction monitoring reported by NOAA as an appropriate proxy for
Moorings Seward is three individuals per day. During 8 years of surveys
near Sitka, Straley et al. (2017) only documented seven Pacific white-
sided dolphins, therefore, we do not reasonably expect the species to
occur in the vicinity of Moorings Sitka.
Dall's porpoise--Dall's porpoise are anticipated to occur in the
vicinity of both locations. At Moorings Seward, the expected occurrence
rate is approximately 0.25 animals per day, and the average group size
throughout Alaskan waters is estimated to be between 2-12 individuals.
We therefore estimate that approximately one group of up to six
individuals could occur over 22 non-consecutive days of in-water work.
At Moorings Sitka, the estimated density of Dall's porpoise is 0.121
individuals/km\2\.
Harbor porpoise--Only the Yakutat/Southeast Alaska Offshore Waters
stock and the Gulf of Alaska stock are expected to be encountered in
the project areas. The Gulf of Alaska stock range includes Moorings
Seward while the Yakutat/Southeast Alaska Offshore Waters stock's range
includes Moorings Sitka. The estimated density of harbor porpoises at
Moorings Seward is 0.4547/km\2\ and the estimated occurrence at
Moorings Sitka is one group of five individuals every 2 weeks.
Northern fur seal--Northern fur seals are not expected near
Moorings Seward and one individual per month is estimated to occur at
Moorings Sitka.
Steller sea lion--Only the Western stock of Steller sea lion is
expected to occur at Moorings Seward with an estimated occurrence of
two individuals per day. Both the Western and Eastern stocks may occur
at Moorings Sitka, which is located in the Central Outer Coast
population mixing zone delineated by Hastings et al. (2020). Based on
these data, 2.2 percent of Steller sea lions near Sitka are expected to
be from the Western stock while 97.8 percent are expected to be from
the Eastern stock (Hastings et al., 2020), and it is estimated that one
to two groups of two individuals per day may occur at Moorings Sitka,
with a likelihood of no more than one group per day in the Level A
harassment zone and likelihood of up to one additional (for a total of
two) group per day in the level B harassment zone.
Harbor seal--There are 12 stocks of harbor seals in Alaska, 2 of
which occur in the project areas: (1) the Prince
[[Page 60379]]
William Sound stock ranges from Elizabeth Island off the southwest tip
of the Kenai Peninsula to Cape Fairweather, including Moorings Seward;
and (2) the Sitka/Chatham Strait stock ranges from Cape Bingham south
to Cape Ommaney, extending inland to Table Bay on the west side of Kuiu
Island and north through Chatham Strait to Cube Point off the west
coast of Admiralty Island, and as far east as Cape Bendel on the
northeast tip of Kupreanof Island, which includes Moorings Sitka. Daily
occurrence of harbor seals at Moorings Sitka is estimated as 48.95
individuals/day and at Moorings Sitka one to two groups of 2.1
individuals/day are estimated based on previous monitoring in the
vicinity, with a likelihood of no more than one group per day in the
Level A harassment zone and likelihood of up to one additional (for a
total of two) group per day in the level B harassment zone.
Take Estimation
Here we describe how the information provided above is synthesized
to produce a quantitative estimate of the take that is reasonably
likely to occur and proposed for authorization.
Neither the applicant nor NMFS have fine-scale data to
quantitatively assess the number of animals in the relatively small
predicted Level A harassment zones at either location. Therefore, we
assumed that, for cryptic species (e.g., Steller sea lion, Pacific
white-sided dolphin (Moorings Seward only), harbor seal, harbor
porpoise), up to 10 percent of the animals that entered the Level B
harassment zone could enter the Level A harassment zone undetected,
potentially accumulating sound exposure that rises to the level of
Level A harassment.
For species with observational data, the following equation was
used to estimate take by Level B harassment, where daily occurrence is
measured as individuals per day:
Estimated take = (daily occurrence x number of days) - Level A
harassment takes
For species with observational data, the following equation was
used to estimate take by Level A harassment, where daily occurrence is
multiplied by the number of days of work, which is then multiplied by
10 percent:
Estimated take = (daily occurrence x number of days) x 10 percent
For species with density data, the following equation was used to
estimate take by Level B harassment, where ensonified area is measured
as km\2\:
Estimated take = (species density x daily ensonified Level B harassment
area x number of days)-Level A harassment takes
For species with density data, the following equation was used to
estimate take by Level A harassment, where species density is
multiplied by the daily ensonified Level A harassment area multiplied
by the number of days of work:
Estimated take = (species density x daily ensonified Level A harassment
area x number of days)
Table 15 summarizes proposed amounts of take by both Level A and
Level B harassment, as well as the percentage of each stock expected to
be taken, at Moorings Seward.
Table 15--Proposed Take of Marine Mammals by Level A and Level B Harassment and Percent of Stock Proposed To Be Taken at Moorings Seward
--------------------------------------------------------------------------------------------------------------------------------------------------------
SAR Percentage of
Species Stock Level A Level B Total abundance population
--------------------------------------------------------------------------------------------------------------------------------------------------------
Steller sea lion................................ Western........................... 4 40 44 49,837 0.09
Harbor seal..................................... Prince William Sound.............. 98 980 1,078 44,756 2.41
Killer whale *.................................. Alaska Resident................... 0 21 21 1,920 1.09
Killer whale *.................................. Eastern North Pacific Gulf of 0 7 7 587 1.19
Alaska, Aleutian Islands and
Bering Sea Transient.
Pacific white-sided dolphin..................... North Pacific..................... 6 60 66 26,880 0.25
Harbor porpoise................................. Gulf of Alaska.................... 5 18 23 31,046 0.07
Dall's porpoise................................. Alaska............................ 1 5 6 UND UND
Humpback whale.................................. Hawai[revaps]i.................... 0 20 20 11,278 0.18
Humpback whale.................................. Mexico-North Pacific.............. 0 2 2 N/A N/A
Gray whale...................................... Eastern North Pacific............. 0 1 1 26,960 0.00
Fin whale....................................... Northeast Pacific................. 0 3 3 UND UND
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Humpback whale stock attribution: 89% Hawai[revaps]i and 11% Mexico-North Pacific.
* Percent of stock impacted for killer whales was estimated assuming each stock is taken in proportion to its population size at each location from the
total take. At Moorings Seward, the Alaska Resident and Gulf of Alaska stocks are the only stocks present. Of these, the Alaska Resident stock
represents approximately 76 percent of the available animals, while the Gulf of Alaska stock represents approximately 23 percent. This division was
replicated for Moorings Sitka for all present stocks. Takes were then calculated for each site based on the proportional representation of available
stocks, so for Moorings Seward, this results in 21 Level B harassment takes of the Alaska Resident stock of killer whale and seven Level B harassment
takes of the Gulf of Alaska stock of killer whale. Total takes for each stock are shown as a percentage of the stock size.
Table 16 summarizes amount of take proposed to be authorized by
both Level A and Level B harassment, as well as the percentage of each
stock expected to be taken, at Moorings Sitka.
Table 16--Proposed Take of Marine Mammals by Level A and Level B Harassment and Percent of Stock Proposed To Be Taken at Moorings Sitka
--------------------------------------------------------------------------------------------------------------------------------------------------------
SAR Percentage of
Species Stock Level A Level B Total abundance population
--------------------------------------------------------------------------------------------------------------------------------------------------------
Steller sea lion................................ Western........................... 1 7 8 49,837 0.02
Steller sea lion................................ Eastern........................... 16 336 352 36,308 0.97
Northern fur seal............................... Eastern Pacific................... 0 3 3 626,618 0.00
[[Page 60380]]
Harbor seal..................................... Sitka/Chatham Strait.............. 18 342 360 13,289 2.71
Killer whale *.................................. Alaska Resident................... 0 55 55 1,920 2.86
Killer whale *.................................. Eastern North Pacific Gulf of 0 17 17 587 2.90
Alaska, Aleutian Islands and
Bering Sea Transient.
Killer whale *.................................. Northern Resident................. 0 8 8 302 2.65
Killer whalex*.................................. West Coast Transient.............. 0 10 10 349 2.87
Harbor porpoise................................. Yakutat/Southeast Alaska Offshore 3 32 35 N/A N/A
Waters.
Dall's porpoise................................. Alaska............................ 14 52 66 UND UND
Humpback whale.................................. Hawai[revaps]i.................... 0 43 43 11,278 0.38
Humpback whale.................................. Mexico-North Pacific.............. 0 1 1 N/A N/A
Gray whale...................................... Eastern North Pacific............. 0 22 22 26,960 0.08
Minke whale..................................... Alaska............................ 0 22 22 N/A N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Steller sea lion stock attribution: 97.8% Eastern DPS and 2.2% Western DPS at Moorings Sitka. Humpback whale stock attribution: 98% Hawai[revaps]i
and 2% Mexico-North Pacific.
* Percent of stock impacted for killer whales was estimated assuming each stock is taken in proportion to its population size at each location from the
total take. At Moorings Sitka, the Alaska Resident, Gulf of Alaska, Northern Resident, and West Coast Transient stocks are expected, and the Alaska
Resident stock represents approximately 60 percent of the available animals, the Gulf of Alaska stock represents approximately 19 percent, the
Northern Resident stock represents approximately 10 percent, and the West Coast Transient represents approximately 11 percent. Takes were then
calculated based on the proportional representation of available stocks, which results in 55 Level B harassment takes of the Alaska Resident stock, 17
Level B harassment takes of the Gulf of Alaska stock, 8 Level B harassment takes of the Northern Resident stock, and 10 Level B harassment takes of
the West Coast Transient stock. Total takes for each stock are shown as a percentage of the stock size.
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses. NMFS regulations require applicants for incidental
take authorizations to include information about the availability and
feasibility (economic and technological) of equipment, methods, and
manner of conducting the activity or other means of effecting the least
practicable adverse impact upon the affected species or stocks, and
their habitat (50 CFR 216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat, as
well as subsistence uses. This considers the 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.
For each IHA, the USCG must:
<bullet> Ensure that construction supervisors and crews, the
monitoring team, and relevant USCG staff are trained prior to the start
of all pile driving and DTH activity, so that responsibilities,
communication procedures, monitoring protocols, and operational
procedures are clearly understood. New personnel joining during the
project must be trained prior to commencing work;
<bullet> Employ PSOs and establish monitoring locations as
described in the application and the IHA. The USCG must monitor the
project area to the maximum extent possible based on the required
number of PSOs, required monitoring locations, and environmental
conditions. For all pile driving and removal at least one PSO must be
used. The PSO will be stationed as close to the activity as possible;
<bullet> The placement of the PSOs during all pile driving and
removal and DTH activities will ensure that the entire shutdown zone is
visible during pile installation;
<bullet> Monitoring must take place from 30 minutes prior to
initiation of pile driving or DTH activity (i.e., pre-activity
monitoring) through 30 minutes post-activity of pile driving or DTH
activity;
<bullet> Pre-activity monitoring must be conducted during periods
of visibility sufficient for the lead PSO to determine that the
shutdown zones indicated in table 17 are clear of marine mammals. Pile
driving and DTH may commence following 30 minutes of observation when
the determination is made that the shutdown zones are clear of marine
mammals;
<bullet> The USCG must use soft start techniques when impact pile
driving. Soft start requires contractors to provide an initial set of
three strikes at reduced energy, followed by a 30-second waiting
period, then two subsequent reduced-energy strike sets. A soft start
must be implemented at the start of each day's impact pile driving and
at any time following cessation of impact pile driving for a period of
30 minutes or longer; and
<bullet> If a marine mammal is observed entering or within the
shutdown zones indicated in table 17, pile driving and DTH must be
delayed or halted. If pile driving is delayed or halted due to the
presence of a marine mammal, the activity may not commence or resume
until either the animal has voluntarily exited and been visually
confirmed beyond the shutdown zone (table 17) or 15 minutes have passed
without re-detection of the animal.
As proposed by the applicant, in-water activities will take place
only between civil dawn and civil dusk (generally 30 minutes after
sunrise and
[[Page 60381]]
up to 45 minutes before sunset), and work may not begin without
sufficient daylight to conduct pre-activity monitoring, and may extend
up to 3 hours past sunset, as needed to either completely remove an in-
process pile or to embed a new pile far enough to safely leave piles in
place until work can resume the next day; during conditions with a
Beaufort Sea State of four or less; and when the entire shutdown zones
are visible.
Protected Species Observers
The placement of PSOs during all pile driving activities (described
in Proposed Monitoring and Reporting) would ensure that the entire
shutdown zone is visible. Should environmental conditions deteriorate
such that the entire shutdown zone would not be visible (e.g., fog,
heavy rain), pile driving would be delayed until the PSO is confident
marine mammals within the shutdown zone could be detected.
PSOs would monitor the full shutdown zones and the Level B
harassment zones to the extent practicable. Monitoring zones provide
utility for observing by establishing monitoring protocols for areas
adjacent to the shutdown zones. Monitoring zones enable observers to be
aware of and communicate the presence of marine mammals in the project
areas outside the shutdown zones and thus prepare for a potential
cessation of activity should the animal enter the shutdown zone.
Pre- and Post-Activity Monitoring
Monitoring must take place from 30 minutes prior to initiation of
pile driving activities (i.e., pre-clearance monitoring) through 30
minutes post-completion of pile driving. Prior to the start of daily
in-water construction activity, or whenever a break in pile driving of
30 minutes or longer occurs, PSOs would observe the shutdown and
monitoring zones for a period of 30 minutes. The shutdown zone would be
considered cleared when a marine mammal has not been observed within
the zone for a 30-minute period. If a marine mammal is observed within
the shutdown zones listed in table 9, pile driving activity would be
delayed or halted. If work ceases for more than 30 minutes, the pre-
activity monitoring of the shutdown zones would commence. A
determination that the shutdown zone is clear must be made during a
period of good visibility (i.e., the entire shutdown zone and
surrounding waters must be visible to the naked eye).
Soft-Start Procedures for Impact Driving
Soft-start procedures provide additional protection to marine
mammals by providing warning and/or giving marine mammals a chance to
leave the area prior to the hammer operating at full capacity. If
impact pile driving is necessary to achieve required tip elevation, the
USCG would be required to provide an initial set of three strikes from
the hammer at reduced energy, followed by a 30-second waiting period,
then two subsequent reduced-energy strike sets. Soft-start would be
implemented at the start of each day's impact pile driving and at any
time following cessation of impact pile driving for a period of 30
minutes or longer.
Shutdown Zones
The USCG must establish shutdown zones for all pile driving
activities. The purpose of a shutdown zone is generally to define an
area within which shutdown of the activity would occur upon sighting of
a marine mammal (or in anticipation of an animal entering the defined
area). Shutdown zones would be based upon the Level A harassment
thresholds for each pile size/type and driving method where applicable,
as shown in table 17. During all in-water piling activities, the USCG
has proposed to implement a minimum 30 m shutdown zone, larger than
NMFS' typical requirement of a minimum 10 m shutdown zone, with the
addition of larger zones during DTH. These distances exceed the
estimated Level A harassment isopleths described in tables 12 and 13.
Adherence to this expanded shutdown zone will reduce the potential for
the take of marine mammals by Level A harassment but, due to the large
zone sizes and small, inconspicuous nature of five species (Steller sea
lion, Pacific white-sided dolphin (Moorings Seward only), harbor seal,
harbor porpoise, Dall's porpoise), the potential for Level A harassment
cannot be completely avoided. If a marine mammal is observed entering,
or detected within, a shutdown zone during pile driving activity, the
activity must be stopped until there is visual confirmation that the
animal has left the zone or the animal is not sighted for a period of
15 minutes. Proposed shutdown zones for each activity type are shown in
table 17.
All marine mammals would be monitored in the Level B harassment
zones and throughout the area as far as visual monitoring can take
place. If a marine mammal enters the Level B harassment zone, in-water
activities would continue and PSOs would document the animal's presence
within the estimated harassment zone.
Table 17--Proposed Shutdown Zones and Harassment Zones
--------------------------------------------------------------------------------------------------------------------------------------------------------
Shutdown Shutdown Shutdown Shutdown Shutdown Harassment
Activity zone (m) zone (m) zone (m) zone (m) zone (m) Harassment zone zone (m) at
for LF for MF for HF for PW for OW (m) at Seward Sitka
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory pile extraction............................. 30 30 30 30 30 4,645 6,310
Impact drive plastic pile............................. 30 30 30 30 30 N/A 5
Impact drive timber pile.............................. 30 30 30 30 30 N/A 50
DTH (Impulsive component) concrete pile............... 1,955 85 2,325 1,050 85 39,815 39,815
Vibratory concrete pile settling...................... 30 30 30 30 30 7,360 7,360
Impact drive concrete pile proofing................... 30 30 30 30 30 545 545
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Level A (PTS onset) harassment would only potentially result from DTH rock socket drilling activities that would generate underwater noise in
exceedance of Level A harassment thresholds for all marine mammal hearing groups beyond the 30-m shutdown zone that will be implemented for all in-
water activities. Therefore, larger shutdown zones will be implemented during DTH activities and at least two additional PSOs will be assigned to a
captained vessel at one or more monitoring locations that provide full views of the shutdown zones and as much of the monitoring zones as possible.
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
[[Page 60382]]
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.
Visual Monitoring
Marine mammal monitoring must be conducted in accordance with the
conditions in this section and this IHA. Marine mammal monitoring
during pile driving activities would be conducted by up to five PSOs
meeting NMFS' standards and in a manner consistent with the following:
<bullet> PSOs must be independent of the activity contractor (for
example, employed by a subcontractor) and have no other assigned tasks
during monitoring periods;
<bullet> At least one PSO would have prior experience performing
the duties of a PSO during construction activity pursuant to a NMFS-
issued incidental take authorization;
<bullet> Other PSOs may substitute other relevant experience,
education (degree in biological science or related field), or training
for prior experience performing the duties of a PSO during construction
activity pursuant to a NMFS-issued incidental take authorization;
<bullet> A team of three PSOs (up to five PSOs) at up to three
locations (including two PSOs on a captained vessel in the case of a
five-member team) will conduct the marine protected species monitoring
depending on the activity and size of the relevant shutdown and
monitoring zones;
<bullet> Where a team of three or more PSOs is required, a lead
observer or monitoring coordinator must be designated. The lead
observer must have prior experience performing the duties of a PSO
during construction activity pursuant to a NMFS-issued incidental take
authorization;
<bullet> For activities with monitoring zones beyond the visual
range of a single PSO (i.e., DTH), additional monitoring locations or
the use of a vessel with captain and up to three other PSOs (depending
on size of the monitoring zones) will conduct monitoring; and
<bullet> PSOs must be approved by NMFS prior to beginning any
activity subject to the IHA.
PSOs should have the following additional qualifications:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including the identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates, times, and reason for implementation
of mitigation (or why mitigation was not implemented when required);
and marine mammal behavior; and
<bullet> Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
For all pile driving activities, at least one PSO (up to five PSOs)
must be stationed at the best possible vantage point to monitor the
shutdown zones and as much of the Level B harassment zones as possible.
A team of three PSOs (up to five PSOs) at up to three locations
(including two PSOs on a captained vessel in the case of a five-member
team) would conduct marine mammal monitoring depending on the activity
and size of monitoring zones. PSOs would be equipped with high quality
binoculars for monitoring and radios or cells phones for maintaining
contact with work crews. Monitoring would be conducted 30 minutes
before, during, and 30 minutes after all in-water construction
activities. In addition, PSOs would record all incidents of marine
mammal occurrence, regardless of distance from activity, and would
document any behavioral reactions in concert with distance from piles
being driven or removed. Pile driving activities include the time to
install or remove a single pile or series of piles, as long as the time
elapsed between uses of the pile driving equipment is no more than 30
minutes.
Reporting
A draft marine mammal monitoring report will be submitted to NMFS
within 90 days after the completion of pile driving and removal
activities for each IHA, or 60 days prior to a requested date of
issuance from any future IHAs for projects at the same location,
whichever comes first. The report will include an overall description
of work completed, a narrative regarding marine mammal sightings, and
associated PSO data sheets. Specifically, the report must include:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> Construction activities occurring during each daily
observation period, including the number and type of piles driven or
removed and by what method (i.e., impact, vibratory, DTH) and the total
equipment duration for vibratory removal for each pile or total number
of strikes for each pile (impact driving);
<bullet> PSO locations during marine mammal monitoring;
<bullet> Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance;
<bullet> Upon observation of a marine mammal, the following
information:
[cir] Name of PSO who sighted the animal(s) and PSO location and
activity at the time of sighting;
[cir] Time of sighting;
[cir] Identification of the animal(s) (e.g., genus/species, lowest
possible
[[Page 60383]]
taxonomic level, or unidentifiable), PSO confidence in identification,
and the composition of the group if there is a mix of species;
[cir] Distance and bearing of each marine mammal observed relative
to the pile being driven for each sighting (if pile driving was
occurring at time of sighting);
[cir] Estimated number of animals (min/max/best estimate);
[cir] Estimated number of animals by cohort (adults, juveniles,
neonates, group composition, sex class, etc.);
[cir] Animal's closest point of approach and estimated time spent
within the harassment zone; and
[cir] Description of any marine mammal behavioral observations
(e.g., observed behaviors such as feeding or traveling), including an
assessment of behavioral responses thought to have resulted from the
activity (e.g., no response or changes in behavioral state such as
ceasing feeding, changing direction, flushing, or breaching);
<bullet> Number of marine mammals detected within the harassment
zones and shutdown zones; by species; and
<bullet> Detailed information about any implementation of any
mitigation triggered (e.g., shutdowns and delays), a description of
specific actions that ensured, and resulting changes in behavior of the
animal(s), if any.
If no comments are received from NMFS within 30 days, the draft
reports will constitute the final reports. If comments are received, a
final report addressing NMFS comments must be submitted within 30 days
after receipt of comments.
Reporting Injured or Dead Marine Mammals
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, the USCG must immediately
cease the specified activities and report the incident to the Office of
Protected Resources (<a href="/cdn-cgi/l/email-protection#0f5f5d21465b5f21426061667b607d6661685d6a7f607d7b7c4f61606e6e21686079"><span class="__cf_email__" data-cfemail="2c7c7e0265787c026143424558435e45424b7e495c435e585f6c42434d4d024b435a">[email protected]</span></a>), NMFS, and to
the Alaska Regional Stranding Coordinator as soon as feasible. If the
death or injury was clearly caused by the specified activity, the USCG
must immediately cease the specified activities until NMFS is able to
review the circumstances of the incident and determine what, if any,
additional measures are appropriate to ensure compliance with the terms
of the IHA. The IHA-holder must not resume their activities until
notified by NMFS. The report must include the following information:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and
<bullet> General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the discussion of our analysis applies to all
the species listed in table 5, given that the anticipated effects of
this activity on these different marine mammal stocks are expected to
be similar. There is little information about the nature or severity of
the impacts, or the size, status, or structure of any of these species
or stocks that would lead to a different analysis for this activity.
Pile driving and DTH activities associated with the specified
activities, as described previously, have the potential to disturb or
displace marine mammals. Specifically, the specified activities may
result in take in the form of Level B harassment only for all species
other than the Steller sea lion, harbor seal, Pacific white-sided
dolphin, harbor porpoise, and Dall's porpoise from underwater sounds
generated from pile driving and DTH. Potential takes could occur if
individual marine mammals are present in the ensonified areas when pile
driving or DTH is occurring.
No serious injury or mortality would be expected, even in the
absence of required mitigation measures, given the nature of the
activities. For all species other than Steller sea lion, harbor seal,
Pacific white-sided dolphin, harbor porpoise, and Dall's porpoise, no
Level A harassment is anticipated due to the confined nature of the
facilities, ability to position PSOs at stations from which they can
observe the entire shutdown zones, and the high visibility of the
species expected to be present at each site. The potential for injury
is small for mid- and low-frequency cetaceans and sea lions, and is
expected to be essentially eliminated through implementation of the
planned mitigation measures--soft start (for impact driving), and
shutdown zones. Further, no take by Level A harassment is anticipated
for killer whales, humpback whales, gray whales, fin whales, or minke
whales due to the application of planned mitigation measures and the
small Level A harassment zones (for killer whales only). The potential
for harassment would be minimized through the construction method and
the implementation of the planned mitigation measures (see Proposed
Mitigation).
Take by Level A harassment is proposed for Steller sea lion, harbor
seal, Pacific white-sided dolphin, harbor porpoise, and Dall's
porpoise. Due to their inconspicuous nature, it is possible an
individual of one of these species could enter the Level A harassment
zone undetected and remain within that zone for a duration long enough
to incur PTS. Any take by Level A harassment is expected to arise from,
at most, a small degree of PTS (i.e., minor degradation of hearing
capabilities within regions of hearing that align most completely with
the energy produced by impact pile driving such as the low-frequency
region below 2 kHz), not severe hearing impairment or impairment within
the ranges of greatest hearing sensitivity. Animals
[[Page 60384]]
would need to be exposed to higher levels and/or longer duration than
are expected to occur here in order to incur any more than a small
degree of PTS.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect any of the species
or stocks through effects on annual rates of recruitment or survival:
<bullet> No serious injury or mortality is anticipated or proposed
for authorization;
<bullet> Level A harassment would be very small amounts and of low
degree;
<bullet> Level B harassment would be primarily in the form of
behavioral disturbance, resulting in avoidance of the project areas
around where piling is occurring, with some low-level TTS that may
limit the detection of acoustic cues for relatively brief amounts of
time in relatively confined footprints of the activities;
<bullet> The ensonified areas are very small relative to the
overall habitat ranges of all species and stocks, and would not
adversely affect ESA-designated critical habitat for any species or any
areas of known biological importance;
<bullet> The amount of take proposed for authorization accounts for
no more than, at most, 3 percent of any stock that may occur in the
project areas;
<bullet> The lack of anticipated significant or long-term negative
effects to marine mammal habitat; and
<bullet> The implementation of mitigation measures to minimize the
number of marine mammals exposed to injurious levels of sound and
ensure take by Level A harassment is, at most, a small degree of PTS.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the 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 amount of take NMFS proposes to authorize is below one-third of
the estimated stock abundance of all species and stocks (take of
individuals is less than 3 percent of the abundance of the affected
stocks at Moorings Seward and Moorings Sitka; see tables 15, 16). This
is likely a conservative estimate because it assumes all takes are of
different individual animals, which is likely not the case. Some
individuals may return multiple times in a day but PSOs would count
them as separate takes if they cannot be individually identified.
There are no valid abundance estimates available for humpback
whales (Mexico-North Pacific stock), fin whales (Northeast Pacific
stock), minke whales (Alaska stock), Dall's porpoises (Alaska stock),
and harbor porpoises (Yakutat/Southeast Alaska Offshore Waters stock).
There is no recent stock abundance estimate for the Mexico-North
Pacific stock of humpback whale and the minimum population is
considered unknown (Young et al., 2023). There are two minimum
population estimates for this stock that are over 15 years old: 2,241
(Mart[iacute]nez-Aguilar, 2011) and 766 (Wade, 2021). Using either of
these estimates, the 3 takes by Level B harassment proposed for
authorization (2 at Moorings Seward, 1 at Moorings Sitka) represent
small numbers of the stock. Muto et al. (2021) estimate the minimum
stock size for the Northeast Pacific stock of fin whale for the areas
surveyed is 2,554 individuals. Therefore, the 3 takes by Level B
harassment of this stock at Moorings Seward represent small numbers of
this stock. There is also no current abundance estimate of the Alaska
stock of minke whale but over 2,000 individuals were documented in
areas recently surveyed (Muto et al., 2021). Therefore, the 22 takes by
Level B harassment at Moorings Sitka represent small numbers of this
stock, even if each take occurred to a new individual.
The most recent stock abundance estimate of the Alaska stock of
Dall's porpoise was 83,400 animals and, although the estimate is more
than 8 years old, it is unlikely this stock has drastically declined
since that time. Therefore, the 72 takes proposed for authorization, 15
by Level A and 57 by Level B harassment (6 total at Moorings Seward, 66
total at Moorings Sitka), represent small numbers of this stock. A
current stock-wide abundance estimate for the Yakutat/Southeast Alaska
Offshore Waters stock of harbor porpoises in offshore waters (which
includes Moorings Sitka) is not available (Young et al., 2023).
However, Muto et al. (2021) estimate the minimum stock size for the
areas surveyed is 1,057 individuals. Therefore, the 35 takes proposed
for authorization at Moorings Sitka (3 by Level A harassment, 32 by
Level B harassment) represent small numbers of this stock.
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.
There are two species of marine mammals analyzed herein that have
been taken as part of subsistence harvests in Resurrection Bay and
southeast Alaska: Steller sea lion and harbor seal. The most recent
data on subsistence-harvested marine mammals near Seward is of harbor
seals in 2002, and the most recent data near Sitka is of both harbor
seals and Steller sea lions in 2013 (ADFG, 2013). The most recent
subsistence hunt survey data available indicated approximately 11
percent of Sitka households used subsistence-caught marine mammals
(Sill and Koster, 2013) and no data is available since that time.
The proposed project is not likely to adversely impact the
availability of any
[[Page 60385]]
marine mammal species or stocks that are commonly used for subsistence
purposes or impact subsistence harvest of marine mammals in the region.
Although the proposed activities are located in regions where
subsistence harvests have occurred historically, subsistence harvest of
marine mammals is rare in the project areas and local subsistence users
have not expressed concern about this project. Both locations are
adjacent to heavily traveled industrialized waterways and all project
activities will take place within closed and secured waterfronts where
subsistence activities do not generally occur. The project also will
not have an adverse impact on the availability of marine mammals for
subsistence use at locations farther away, where the proposed
construction activities are not expected to take place. Some minor,
short-term harassment of Steller sea lions and harbor seals could
occur, but any effects on subsistence harvest activities in the project
areas will be minimal, and not have an adverse impact.
Based on the description of the specified activity and the measures
described to minimize adverse effects on the availability of marine
mammals for subsistence purposes, and the proposed mitigation and
monitoring measures, NMFS has preliminarily determined that there will
not be an unmitigable adverse impact on subsistence uses from the
USCG's proposed activities.
Endangered Species Act
Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.)
requires that each Federal agency 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 NMFS Alaska Regional Office.
NMFS is proposing to authorize take of Western DPS Steller sea
lion, Mexico-North Pacific stock of humpback whale, and the Northeast
Pacific stock of fin whale, which are listed under the ESA. The Permits
and Conservation Division has requested initiation of section 7
consultation with the Alaska Regional Office for the issuance of this
IHA. NMFS will conclude the ESA consultation prior to reaching a
determination regarding the proposed issuance of the authorizations.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue two IHAs to the USCG for construction of FRC homeporting docks in
Seward and Sitka for a period of 1 year each, provided the previously
mentioned mitigation, monitoring, and reporting requirements are
incorporated. Drafts of the proposed IHAs can be found at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>.
Request for Public Comments
We request comment on our analyses, the proposed authorizations,
and any other aspect of this notice of proposed IHAs for the proposed
construction project. We also request comment on the potential renewal
of these proposed IHAs 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 these IHAs or subsequent
renewal IHAs.
On a case-by-case basis, NMFS may issue a one-time, 1-year renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activity section of this notice is planned; or (2) the activities as
described in the Description of Proposed Activity section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
<bullet> A request for renewal is received no later than 60 days
prior to the needed renewal IHA effective date (recognizing that the
renewal IHA expiration date cannot extend beyond one year from
expiration of the initial IHA).
<bullet> The request for renewal must include the following:
[cir] 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
[cir] A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
<bullet> Upon review of the request for renewal, the status of the
affected species or stocks, and any other pertinent information, NMFS
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: July 22, 2024.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2024-16412 Filed 7-24-24; 8:45 am]
BILLING CODE 3510-22-P
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