[Federal Register Volume 89, Number 143 (Thursday, July 25, 2024)]
[Notices]
[Pages 60359-60385]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[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 
[email protected]. Electronic copies of the application and 
supporting documents, as well as a list of the references cited in this 
document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. 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 https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act 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
----------------------------------------------------------------------------------------------------------------
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
----------------------------------------------------------------------------------------------------------------
                                                                                                      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
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                                                                                                     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 (https://www.fisheries.noaa.gov/find-species).
    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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                     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).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Family Phocidae (earless seals)
--------------------------------------------------------------------------------------------------------------------------------------------------------
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
  (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/).
\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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region. 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 (SELcum) in an 
accelerating fashion: At low exposures with lower SELcum, 
the amount of TTS is typically small and the growth curves have shallow 
slopes. At exposures with higher SELcum, 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 SELcum 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 https://www.fisheries.noaa.gov/action/incidental-take-authorization-faa-biorka-island-dock-replacement-project-sitka-ak).
    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: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

[[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 * log10 (R1/R2),

Where:

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

    The recommended TL coefficient for most nearshore environments is 
the practical spreading value of 15. This value results in an expected 
propagation environment that would lie between spherical and 
cylindrical spreading loss conditions, which is the most appropriate 
assumption for 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:
     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;
     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;
     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;
     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;
     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;
     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
     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:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
     Mitigation and monitoring effectiveness.

Visual Monitoring

    Marine mammal monitoring must be conducted in accordance with the 
conditions in this section and 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:
     PSOs must be independent of the activity contractor (for 
example, employed by a subcontractor) and have no other assigned tasks 
during monitoring periods;
     At least one PSO would have prior experience performing 
the duties of a PSO during construction activity pursuant to a NMFS-
issued incidental take authorization;
     Other PSOs may substitute 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;
     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;
     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;
     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
     PSOs must be approved by NMFS prior to beginning any 
activity subject to the IHA.
    PSOs should have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     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
     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:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including the number and type of piles driven or 
removed and by what method (i.e., impact, vibratory, DTH) and the total 
equipment duration for vibratory removal for each pile or total number 
of strikes for each pile (impact driving);
     PSO locations during marine mammal monitoring;
     Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
     Upon observation of a marine mammal, the following 
information:
    [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);
     Number of marine mammals detected within the harassment 
zones and shutdown zones; by species; and
     Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensured, and resulting changes in behavior of the 
animal(s), if any.
    If no comments are received from NMFS within 30 days, the draft 
reports will constitute the final reports. If comments are received, a 
final report addressing NMFS comments must be submitted within 30 days 
after receipt of comments.

Reporting Injured or Dead Marine Mammals

    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the USCG must immediately 
cease the specified activities and report the incident to the Office of 
Protected Resources ([email protected]), NMFS, and to 
the Alaska Regional Stranding Coordinator as soon as feasible. If the 
death or injury was clearly caused by the specified activity, 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:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), as well as 
effects on habitat, and the likely effectiveness of the mitigation. We 
also assess the number, intensity, and context of estimated takes by 
evaluating this information relative to population status. Consistent 
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338, 
September 29, 1989), the impacts from other past and ongoing 
anthropogenic activities are incorporated into this analysis via their 
impacts on the baseline (e.g., as reflected in the regulatory status of 
the species, population size and growth rate where known, ongoing 
sources of 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:
     No serious injury or mortality is anticipated or proposed 
for authorization;
     Level A harassment would be very small amounts and of low 
degree;
     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;
     The ensonified areas are very small relative to the 
overall habitat ranges of all species and stocks, and would not 
adversely affect ESA-designated critical habitat for any species or any 
areas of known biological importance;
     The 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;
     The lack of anticipated significant or long-term negative 
effects to marine mammal habitat; and
     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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.

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:
     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).
     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.
     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