Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to U.S. Coast Guard Base Kodiak Homeporting Facility in Kodiak, Alaska, 12204-12232 [2025-03967]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 90, Number 49 (Friday, March 14, 2025)]
[Notices]
[Pages 12204-12232]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-03967]



[[Page 12203]]

Vol. 90

Friday,

No. 49

March 14, 2025

Part II





Department of Commerce





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National Oceanic and Atmospheric Administration





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Takes of Marine Mammals Incidental to Specified Activities; Taking 
Marine Mammals Incidental to U.S. Coast Guard Base Kodiak Homeporting 
Facility in Kodiak, Alaska; Notice

Federal Register / Vol. 90, No. 49 / Friday, March 14, 2025 / 
Notices

[[Page 12204]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XE174]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to U.S. Coast Guard Base Kodiak 
Homeporting Facility in Kodiak, 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 authorization and possible renewal.

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SUMMARY: NMFS has received a request from the U.S. Coast Guard (USCG) 
for authorization to take marine mammals incidental to 2 years of 
construction activities associated with the Base Kodiak Homeporting 
Facility project in Womens Bay, Kodiak Alaska. Pursuant to the Marine 
Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to issue two consecutive 1-year incidental harassment 
authorizations (IHAs) to incidentally take marine mammals during the 
specified activities. NMFS is also requesting comments on a possible 
one-time, 1-year renewal that could be issued under certain 
circumstances and if all requirements are met, as described in Request 
for Public Comments at the end of this notice. NMFS will consider 
public comments prior to making any final decision on the issuance of 
the requested MMPA authorization and agency responses will be 
summarized in the final notice of our decision.

DATES: Comments and information must be received no later than April 
14, 2025.

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: Kate Fleming, 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 
and can be found in section 3 of the MMPA (16 U.S.C. 1362) and NMFs 
regulations at 50 CFR 216.103.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of two 
consecutive IHAs) 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 qualifies to be categorically 
excluded from further NEPA review.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
request for two consecutive IHAs.

Summary of Request

    On April 8, 2024, NMFS received a request from the USCG for two 
consecutive IHAs to take marine mammals incidental to construction 
associated with the USCG's Base Kodiak Homeport Facility project in 
Womens Bay in Kodiak, Alaska. Following NMFS' review of the application 
and associated discussions, the USCG submitted a revised version on 
June 14, 2024, July 17, 2024, and November 28, 2024. The application 
was deemed adequate and complete on December 7, 2024. The USCG's 
request is for take of 12 species of marine mammals, by Level B 
harassment and, for Dall's porpoise, harbor porpoise, harbor seal, 
northern elephant seal, Steller sea lion, and northern fur seal, 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 plans to upgrade waterfront facilities to construct a 
homeport facility for two Fast Response Cutters and two Offshore Patrol 
Cutters at Base Kodiak, in Womens Bay, Kodiak, Alaska. The facility 
will also provide berthing and supporting infrastructure for temporary 
homeporting (up to 5 years) and long-term major maintenance of an 
additional Fast Response Cutter to be homeported in Seward, Alaska.

[[Page 12205]]

    The activities that have the potential to take marine mammals by 
Level A and Level B harassment include removal and installation of 
timber, concrete, and steel piles by vibratory or impact pile driving 
and down the hole (DTH) drilling. A total of 340 in-water construction 
days are planned across 2 years. The first year of construction 
activities would begin May 19, 2025 and continue through May 18, 2026, 
and the second year of construction activities would begin May 19, 2026 
and continue through May 18, 2027.
    The USCG has requested the issuance of two consecutive IHAs in 
association with the two project years. Given the similarities in 
activities between project years, NMFS is issuing a single Federal 
Register notice to solicit public comments on the issuance of the two 
similar, but separate, IHAs.

Dates and Duration

    The USCG anticipates that the project will take place over 2 years. 
The Year 1 IHA would be effective from May 19, 2025 through May 18, 
2026, and the Year 2 IHA would be effective from May 19, 2026 through 
May 18, 2027. The specified activities would occur any time during each 
project year, for 7-14 hours each day, depending on time of year, 
during daylight hours only. A total of 264 days of in-water work are 
planned in Year 1 and 76 construction days of in-water work are planned 
in year 2.

Specific Geographic Region

    Coast Guard Base Kodiak is located on Womens Bay, a largely 
enclosed arm of the larger Chiniak Bay on the northeast side of Kodiak 
Island, Alaska's largest island. Womens Bay is separated from the rest 
of Chiniak Bay by Nyman Peninsula providing a protected harbor for 
Coast Guard vessels. Womens Bay is approximately 3.5 miles (mi) (5.6 
kilometers (km)) long and water depths range from 0 to 100 ft (31 
meters (m)). Near the planned activities, Womens Bay is approximately 
1,700 feet (ft) (519 m) wide and 30 ft (9 m) deep.
    The shores of Womens Bay are relatively undeveloped; only the most 
inner portion of Womens Bay, which includes Base Kodiak and several 
other industries, have significant existing shoreline development. The 
peninsula and the inner shore host several waterfront and industrial 
uses that support current mission-related USCG operations, including 
the operational fuel pier and Cargo Wharf. The Cargo Wharf provides 
berthing for Base Kodiak cutters and visiting vessels and is where 
project activities are planned.
BILLING CODE 3510-22-P

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[GRAPHIC] [TIFF OMITTED] TN14MR25.000

BILLING CODE 3510-22-C

Detailed Description of the Specified Activity

    At Base Kodiak in Womens Bay, Kodiak, Alaska, the USCG is upgrading 
existing waterfront and constructing new shore facilities to construct 
a homeport facility for two Fast Response Cutters and two Offshore 
Patrol Cutters and a temporary homeport facility for an additional Fast 
Response Cutter to be homeported in Seward, Alaska. The USCG estimates 
that Year 1 activities associated with this IHA would include (1) 
demolition of 363 piles (14-in and 24-in timber; 12-in and 14-in steel; 
24-in steel filled with concrete) via vibratory removal, pulling, or 
cutting (a 1.5 multiplier was added to the total number of existing 
piles to be removed to account for uncertainty in the existing site 
conditions. As such, 363 piles is a conservative estimate) (table 1); 
(2) installation of 217 permanent piles (24-in and 42-in steel; and 24-
inch pre-cast square concrete) piles via vibratory and impact pile 
driving and DTH drilling; (3) installation of 488 permanent stone 
columns installed below the mudline below mean high water using 
vibroflation and replacement to improve soil stability; (4) 
installation of 495 permanent stone columns above the mean high water 
(in-air work) using vibroflotation and replacement to improve soil 
stability;

[[Page 12207]]

and (5) vibratory installation and removal of 94 36-in steel temporary 
guide piles. The USCG estimates that Year 2 activities would include 
(1) the installation of 75 permanent piles (24-in, 30-in, 36-in, and 
42-in steel) via vibratory and impact pile driving and DTH; and (2) 
vibratory installation and removal of 44 36-in steel temporary guide 
piles. See the IHA application for a site-specific description of 
activities.
    Vibratory hammers use vibratory drivers to rapidly alternate forces 
by rotating eccentric weights. This process ``liquefies'' the soil 
surrounding the pile so that the pile can either penetrate or be 
removed from the ground with reduced resistance. Vibratory hammers 
would be used for all pile extraction of existing piles (14-inch and 
24-inch timber piles, 12-inch and 14-inch steel piles, and 24-inch 
concrete-filled piles) at an assumed rate of 20 piles per day. For pile 
installation of permanent and temporary piles, a vibratory hammer would 
likely be used until refusal which is anticipated to take 15 to 20 
minutes per pile at a rate of four to six piles per day, after which 
either impact and/or DTH drilling would be employed to reach depth.
    If piles cannot be removed using vibratory methods, they would be 
cut-off at the mudline using a hydraulic chainsaw or hydraulic shearing 
device operated by divers.
    An impact hammer is a steel device that uses air or ignited fuel to 
lift a heavy piston, then allows gravity to drop the piston on top of 
the pile, repeating until the pile is driven into the substrate 
(Washington State Department of Transportation [WSDOT], 2020). Impact 
pile driving is anticipated to occur during pile installation; piles 
would be impact-driven at a rate of four to six piles a day in 
combination with DTH drilling after vibratory methods have met refusal. 
Impact pile driving may also be used during pile proofing.
    DTH systems use a combination of percussive and drilling mechanisms 
to advance a hole into the rock, with or without simultaneously 
advancing a pile or casing into that hole. Drill cuttings and debris at 
the rock face are removed by an air-lift exhaust up the inside of the 
pile (Guan and Miner, 2020). DTH systems will be used to drill a rock 
socket approximately 10 ft (3 m) depth below the pile tip. A rebar cage 
would then be inserted from the base of the socket to some distance 
into the pile and backfilled with concrete from the base of the socket 
to some distance up the pile. DTH methods are anticipated to take 150 
minutes per pile with an installation rate of two piles per day.
    Vibroflotation and replacement is a type of vibrocompaction 
commonly used to partially replace poor soil material by flushing out 
the weaker soil and replacing it with granular fill material resulting 
in a stone column (VGL, 2023). An approximately 30-in-diameter torpedo-
shaped, vibrating probe (a ``vibroflot'') would be vibrated vertically 
into the fill placed within the bulkhead. The resulting hole would then 
be backfilled with gravel as the vibroflot is removed to create stone 
columns within the substrate. This process would be repeated within a 
grid to create stone columns, approximately 2.5 ft (0.8 m) apart. 
Installation of vibroflot columns is assumed to require up to 45 
minutes of vibratory equipment use per column. Vibroflotation and 
replacement would occur above and below the mean high water line. 
Vibroflotation and replacement above the mean high water line (i.e., 
135 vibroflots to stabilize some shoreline outside the bulkhead and 360 
vibroflots to stabilize the approach bulkhead) is not expected to 
result in take of marine mammals as pinnipeds are not known to haulout 
within the project area.
    Permanent piles would be installed through sand and gravel with a 
vibratory hammer until advancement stops. Then, the pile will be driven 
to depth with an impact hammer. If design tip elevation is still not 
achieved, the contractor will utilize a DTH drill to secure the pile. 
Pile depths are expected to be approximately 40 to 70 ft (12 m to 21 m) 
below the mudline and estimated to take approximately 1.25 to 4 hours 
per pile to be driven, depending on which method is utilized. Temporary 
36-inch-diameter piles will be installed and removed using a vibratory 
hammer. Soil-stabilizing stone columns will be installed using 
vibroflotation and replacement, a type of vibrocompaction commonly used 
within offshore fills. To account for unforeseen circumstances like 
poor weather, the contractor added a 20 percent contingency to the 
number of days of effort for each pile type.

                                                      Table 1--Year 1 Summary of Planned Activities
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                                     Number of     Number piles                                                           Days of effort
       Pile size and type            piles for          for        Vibratory piles/    Impact piles/day; -----------------------------------------------
                                      removal      installation      day; min/pile       strikes/pile        Vibratory        Impact            DTH
--------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary Piles:
    36-in Steel.................              94              94  6/day; 20 min/pile  N/A...............              38               0               0
Permanent Piles:
    14-in Timber................             158             N/A  20/day; 10 min/     N/A...............              10             N/A             N/A
                                                                   pile.
    24-in Timber................              24             N/A  20/day; 10 min/     N/A...............               2             N/A             N/A
                                                                   pile.
    12-in Steel.................             147             N/A  20/day; 10 min/     N/A...............               9             N/A             N/A
                                                                   pile.
    14-in Steel.................              30             N/A  20/day; 10 min/     N/A...............               2             N/A             N/A
                                                                   pile.
    24-in Steel.................             N/A              22  6/day; 20 min/pile  6/day; 1,800                     5               5               7
                                                                                       strikes/pile.
    42-in Steel.................             N/A             160  6/day; 20 min/pile  6/day; 2,400                    32              32              48
                                                                                       strikes/pile.
    24-in steel filled with                    4             N/A  20/day; 10 min/     N/A...............               1             N/A             N/A
     concrete.                                                     pile.
    24-in precast square                     N/A              35  6/day; 20 min/pile  6/day; 2,400                     7               7             N/A
     concrete.                                                                         strikes/pile.
Soil stabilizing stone columns:
    Vibroflot soil stabilization             N/A             488  10/day; 45 min/     N/A...............              59             N/A             N/A
     columns [below Mean High                                      pile.
     Water (MHW)].
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                                                      Table 2--Year 2 Summary of Planned Activities
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                                     Number of     Number piles                                                           Days of effort
       Pile size and type            piles for          for        Vibratory piles/    Impact piles/day; -----------------------------------------------
                                      removal      installation      day; min/pile       strikes/pile        Vibratory        Impact            DTH
--------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary Piles:

[[Page 12208]]

 
    36-in Steel.................              44              44  6/day; 20 min/pile  N/A...............              18               0               0
Permanent Piles:
    24-in Steel.................             N/A              20  6/day; 20 min/pile  6/day; 1,800                     4               4               6
                                                                                       strikes/pile.
    30-in Steel.................             N/A              23  6/day; 20 min/pile  6/day; 1,800                     5               5               7
                                                                                       strikes/pile.
    36-in Steel.................             N/A               8  4/day; 20 min/pile  4/day; 1,800                     3               3               3
                                                                                       strikes/pile.
    42-in Steel.................             N/A              24  6/day; 20 min/pile  6/day; 2,400                     5               5               8
                                                                                       strikes/pile.
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    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/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 3 lists all species or stocks for which take is expected and 
proposed to be authorized both proposed IHAs, 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 (M/SI) is anticipated 
or proposed to be authorized here, PBR and annual serious injury and 
mortality from anthropogenic sources are included here as gross 
indicators of the status of the species or stocks and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Alaska and Pacific SARs. All values presented in table 3 are 
the most recent available at the time of publication (including from 
the 2023 SARs) and are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                         Table 3--Species \1\ With Estimated Take From 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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                                                 Order Artiodactyla--Cetacea--Mysticeti (baleen whales)
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Family Eschrichtiidae:
    Gray Whale......................  Eschrichtius robustus..  ENP....................  -, -, N             26,960 (0.05, 25,849,         801        131
                                                                                                             2016).
Family Balaenopteridae (rorquals):
    Fin Whale.......................  Balaenoptera physalus..  Northeast Pacific......  E, D, Y             UND (UND, UND, 2013)          UND        0.6
                                                                                                             \5\.
    Humpback Whale..................  Megaptera novaeangliae.  Hawai[revaps]i.........  -, -, N             11,278 (0.56, 7,265,          127      27.09
                                                                                                             2020).
                                                               Mexico-North Pacific...  T, D, Y             N/A (N/A, N/A, 2006)          UND       0.57
                                                                                                             \6\.
                                                               Western-North Pacific..  E, D, Y             1,0844 (0.88, 1,007,      \7\ 3.4   \7\ 5.82
                                                                                                             2006).
    Minke Whale.....................  Balaenoptera             AK.....................  -, -, N             N/A (N/A, N/A, N/A)           UND          0
                                       acutorostrata.                                                        \8\.
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                                                  Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
    Killer Whale....................  Orcinus orca...........  ENP Alaska Resident....  -, -, N             1,920 (N/A, 1,920,             19        1.3
                                                                                                             2019) \9\.
                                                               ENP Gulf of Alaska,      -, -, N             587 (N/A, 587, 2012)          5.9        0.8
                                                                Aleutian Islands and                         \10\.
                                                                Bering Sea Transient.
    Pacific White-Sided Dolphin.....  Lagenorhynchus           N Pacific..............  -, -, N             26,880 (N/A, N/A,             UND          0
                                       obliquidens.                                                          1990).
Family Phocoenidae (porpoises):
    Dall's Porpoise.................  Phocoenoides dalli.....  AK.....................  -, -, N             UND (UND, UND, 2015)          UND         37
                                                                                                             \11\.
    Harbor Porpoise.................  Phocoena phocoena......  Gulf of Alaska.........  -, -, Y             31,046 (0.21, N/A,            UND         72
                                                                                                             1998).
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                                                               Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    Northern Fur Seal...............  Callorhinus ursinus....  Eastern Pacific........  -, D, Y             626,618 (0.2, 530,376,     11,403        373
                                                                                                             2019).
    Steller Sea Lion................  Eumetopias jubatus.....  Western................  E, D, Y             9,837 (N/A, 49,837,           299        267
                                                                                                             2022) \12\.

[[Page 12209]]

 
Family Phocidae (earless seals):
    Harbor Seal.....................  Phoca vitulina.........  South Kodiak...........  -, -, N             26,448 (N/A, 22,351,          939        127
                                                                                                             2017).
    Northern Elephant Seal..........  Mirounga angustirostris  CA Breeding............  -, -, N             187,697 (N/A, 85,369,       5,122       13.7
                                                                                                             2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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/; Committee on Taxonomy (2022)).
\2\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-cause 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, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.
\5\ The best available abundance estimate for this stock is not considered representative of the entire stock as surveys were limited to a small portion
  of the stock's range. Based on upon this estimate and the Nmin, the PBR value is likely negatively biased for the entire stock.
\6\ Abundance estimates are based upon data collected more than 8 years ago and therefore, current estimates are considered unknown.
\7\ PBR in U.S waters = 0.2, M/SI in U.S. waters = 0.06.
\8\ Reliable population estimates are not available for this stock. See Friday et al., 2013 and Zerbini et al., 2006 for additional information on
  number of minke whales in Alaska.
\9\ Nest is based upon counts of individuals identified from photo-ID catalogs.
\10\ The most recent abundance estimate is likely unreliable as it covered a small area that may not have included females and juveniles, and did not
  account for animals missed on the trackline. The calculated PBR is not a reliable index for the stock as it is based upon a negatively biased minimum
  abundance estimate.
\11\ The best available abundance estimate is likely an underestimate for the entire stock because it is based upon a survey that covered only a small
  portion of the stock's range.
\12\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provides are for the United
  States only. The overall Nmin is 73,211 and overall PBR is 439.

    As indicated above, all 12 species (with 15 managed stocks) in 
table 3 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur. All species that could 
potentially occur in the proposed construction area are included in 
table 3-1 of the application for two consecutive IHAs. While North 
Pacific right whale and Goose-beaked whales have been reported in 
waters off of Kodiak Island, the temporal and/or spatial occurrence of 
these species is such that take is not expected to occur, and they are 
not discussed further beyond the explanation provided here. Goose-
beaked whale prefer deep, pelagic waters and both species would be 
considered very rare in the project area. Additionally, USCG initially 
requested take for sperm whale, but sperm whale inhabit deep water and 
the project area is well outside their range.
    In addition, the northern sea otter may be found in Kodiak, Alaska. 
However, northern sea otter are managed by the U.S. Fish and Wildlife 
Service and are not considered further in this document.

Gray Whale

    Gray whales are found most regularly throughout the North Pacific 
Ocean in shallow coastal waters, occasionally crossing deep waters 
during migration (NOAA Fisheries, 2022f).
    Two distinct population segments (DPS) of gray whale occur in the 
north Pacific: the Eastern North Pacific Distinct Population Segment 
(delisted) and the Western North Pacific DPS (Endangered). The Eastern 
North Pacific DPS is more likely to occur near Kodiak Archipelago.
    During aerial surveys conducted between 1999 and 2005 for Sea Grant 
Gulf Apex Predator-Prey Project, gray whales were primarily observed 
near Ugak Bay, approximately 30 (km) (17 mi) south of the project area 
(straightline) (Sea Grant Alaska, 2012). Smaller numbers of gray whales 
were also observed approximately 15 km (9 mi) to the southeast of the 
project site, in Chiniak Bay (Sea Grant Alaska 2012). During a ferry 
terminal reconstruction and dock improvement project completed in 
Kodiak Harbor, approximately 9 km (6 m) north of site, monitors 
observed marine mammals during construction activities on 110 days 
between November 10, 2015 and June 16, 2016 (ABR, Inc., 2016). No gray 
whales were observed during that time.
    Wild et al., 2023 identified a Gray Whale Migratory Route 
Biologically Important Area (BIA) that intersects with a small portion 
of the project area during the months of January, March, April, May, 
November and December, with an importance score of 1 (the lowest of 
three possible scores (1, 2, or 3), reflecting an intensity score of 2 
(indicating an area of moderate comparative significance) and a Data 
Support score of 1 (lower relative confidence in the available 
supporting data). Wild et al., 2023 also identified the waters to the 
south east of Kodiak Island as a BIA for Gray Whale for feeding during 
June through August, April and May, and September and October. However, 
this BIA does not intersect with the project area.
    While the shallow waters of Womens Bay do not represent preferred 
habitat for large whales, given confirmed gray whale sightings in 
Chiniak Bays, and that a small portion of the project area at the mouth 
of Womens Bay overlaps with a small portion of a BIA for this species, 
gray whales could occur within the project area.

Fin Whale

    Fin whales are known to occur in the Kodiak Island area, though 
their distributions shift between years (Zerbini et al., 2006). Aerial 
surveys conducted between 1999 and 2005 for Sea Grant Gulf Apex 
Predator-Prey Project indicate that some of the highest concentrations 
of fin whale in the region occur around Kodiak Island (Sea Grant 
Alaska, 2012). Across 110 monitoring days between November 10, 2015 and 
June 16, 2016 no fin whales were observed during the ferry terminal 
reconstruction and dock improvement project in Kodiak Harbor (ABR, Inc. 
et al., 2016).
    Wild et al. (2023) identified the waters around Kodiak Island 
(including a small portion of the proposed project area) as a BIA for 
fin whales for feeding during the months of June through September, 
with an importance score of 1 (the lowest of three possible scores (1, 
2, or 3), reflecting an Intensity score of 1 (indicating an area of 
lower

[[Page 12210]]

comparative significance) and a Data Support score of 2 (moderate 
relative confidence in the available supporting data).
    There are no known recent observations of fin whale in Womens Bay 
and the shallow waters of Womens Bay do not represent preferred habitat 
for large whales. However, fin whales do use coastal areas in the Gulf 
of Alaska and a small portion of the project area at the mouth of 
Womens Bay overlaps with a small portion of a BIA for this species, and 
as such, fin whale could occur within the project area.

Humpback Whale

    Humpback whales occur along the coastline of the Kodiak 
Archipelago, including areas just outside of Womens Bay in Chiniak Bay 
(Baraff, 2006; Sea Grant Alaska, 2012). Humpback whales often feed in 
shallower waters closer to the coastline, and have been documented in 
shallow coastal waters near Kodiak Island on some years (Baraff 2006, 
ABR Inc., 2016). The highest concentrations occur near Ugak Bay with 
numbers peaking in August (Sea Grant Alaska, 2012). Across 110 
monitoring days between November 10, 2015 and June 16, 2016 one 
humpback whale was observed during the ferry terminal reconstruction 
and dock improvement project in Kodiak Harbor (ABR, Inc. et al., 2016).
    According to Wade et al., 2023, humpback whales in Kodiak are most 
likely to be from the Hawaii DPS (88 percent probability), with an 11 
percent probability of being form the threatened Mexico DPS and 1 
percent probability of being from the endangered Western North Pacific 
DPS.
    Wild et al. (2023) identified the waters around and to the East of 
Kodiak Island as a feeding BIA for humpback whales during the months of 
May through September, with an importance score of 1 (the lowest of 
three possible scores (1, 2, or 3), reflecting an Intensity score of 2 
(indicating an area of moderate comparative significance) and a Data 
Support score of 1 (lower relative confidence in the available 
supporting data). A small portion of the project area at the mouth of 
Womens Bay overlaps with a small portion of this BIA.
    While the shallow waters of Womens Bay do not represent preferred 
habitat for large whales, given confirmed humpback whale sightings in 
Chiniak Bay, and that a small portion of the project area at the mouth 
of Womens Bay overlaps with a small portion of this BIA, humpback 
whales could occur within the project area

Minke Whale

    During the Gulf of Alaska Line-Transect Survey (GOALS) II, so few 
individuals were sighted in the central Gulf of Alaska that no 
abundance estimates could be computed (Rone et al., 2014). Across 110 
monitoring days between November 10, 2015 and June 16, 2016 no minke 
whales were observed during the ferry terminal reconstruction and dock 
improvement project in Kodiak Harbor (ABR, Inc. et al., 2016). However, 
a few observations of minke whale were recorded in nearshore waters 
near Kodiak Island during line transect surveys conducted in central 
Alaska coastal waters (Zerbini et al., 2006). They are often observed 
in groups of two or three (Guerrero, 2008).

Killer Whale

    The fish-eating Alaska Resident stock of killer whale most commonly 
occurs in nearshore waters near the project area throughout the year. 
Transient killer whales are known to frequent the Kodiak Harbor area to 
hunt Steller sea lions during the months of February through May (UAF, 
2015). A total of 19 killer whales in 4 pods were observed across 110 
days of monitoring between November 10, 2015 and June 16, 2016 during 
the Kodiak Ferry Terminal Dock Improvements Project, (ABR, Inc., 2016). 
The largest of these pods included seven individuals. The Sunaq Tribe 
of Kodiak indicated that killer whales have only been observed in the 
project area approximately two times in the last 5 years (Van Daele, 
2024, personal communication).

Pacific White-Sided Dolphin

    Pacific white-sided dolphins sometimes occur in pods of thousands, 
but group sizes are usually between 10 and 100 animals (Clark, 2008b; 
NMFS, 2022). In 2015, NOAA Fisheries Southwest Fisheries Science Center 
(SWFSC) in collaboration with NOAA Fisheries Alaska Fisheries Science 
Center undertook a robust whale survey along the U.S. and Canadian 
Pacific coast (Weller, 2021). During the SWFSC survey several Pacific 
white-sided dolphins where sighted south of the project area between 
Chiniak and Sitkalidak Island (Weller, 2021). Across 110 monitoring 
days between November 10, 2015 and June 16, 2016 no Pacific white-sided 
dolphins were observed during the ferry terminal reconstruction and 
dock improvement project in Kodiak Harbor (ABR, Inc. et al., 2016). 
Given their preference for deeper, pelagic waters, Pacific white-sided 
dolphins have the potential to occur near Base Kodiak, which is 
situated close to the edge of the continental shelf and the Chiniak 
trough.

Dall's Porpoise

    Several surveys conducted by the National Marine Mammal Laboratory 
(NMML) in the late 1990s documented dozens of Dall's porpoises in 
waters around Kodiak Island (Hobbs, 2004). They have been documented 
around Kodiak Island and occur in nearshore habitats. However, across 
110 monitoring days between November 10, 2015 and June 16, 2016 no 
Dall's porpoise were observed during the ferry terminal reconstruction 
and dock improvement project in Kodiak Harbor (ABR, Inc. et al., 2016), 
and the Sunaq Tribe of Kodiak indicates that this species has never 
been observed in Womens Bay (Van Daele, 2024, personal communication).

Harbor Porpoise

    During the 1992 NMML Harbor Porpoise Aerial Survey conducted around 
Kodiak Island, dozens of harbor porpoises were spotted, with one 
documentation occurring within the action area (Dahlheim et al., 2000). 
Group sizes reported during the same survey averaged 1.41 individuals 
(Dahlheim et al., 2000). A total of six harbor porpoise were documented 
across 110 monitoring days between November 10, 2015 and June 16, 2016 
during the ferry terminal reconstruction and dock improvement project 
in Kodiak Harbor (ABR, Inc. et al., 2016). The largest group size was 
two.
    Harbor porpoises are known to frequent nearshore habitats, 
including bays, and have been documented in bays near the project area 
(Van Daele, 2024, personal communication); therefore, harbor porpoises 
may intermittently enter the project area.

Northern Elephant Seal

    Northern elephant seals are uncommon in Alaskan waters and rarely 
seen as far north as Kodiak Island. However, the Sunaq Tribe of Kodiak 
indicated that a northern elephant seal was observed near the project 
area for about 10 days in 2023.

Northern Fur Seal

    Northern fur seals inhabit deep pelagic waters for most of their 
lives. The closest documented occurrence occurred approximately 60 
miles west of the project area (Hobbs, 2004). Across 110 monitoring 
days between November 10, 2015 and June 16, 2016 no northern fur seal 
were observed during the ferry terminal reconstruction and dock 
improvement project in Kodiak Harbor (ABR, Inc. et al., 2016).

[[Page 12211]]

Steller Sea Lion

    Steller sea lions in the project area are anticipated to be part of 
the western DPS (western stock; Hastings et al., 2020).
    Steller sea lions do not follow traditional migration patterns, but 
will move from offshore rookeries in the summer to more protected 
haulouts closer to shore in the winter. They use rookeries and haulouts 
as resting spots as they follow prey movements and take foraging trips 
for days, usually within a few miles of their rookery or haulout. They 
are generalist marine predators and opportunistic feeders based on 
seasonal abundance and location of prey. Steller sea lions forage in 
nearshore as well as offshore areas, following prey resources.
    Steller sea lion critical habitat in western Alaska includes a 20 
nautical mile buffer around all major haulouts and rookeries as well as 
associated terrestrial, air and aquatic zones, and three large offshore 
foraging areas. The project area would overlap with the aquatic zone of 
Steller sea lion haulouts designated as critical habitat.
    Limited data exist to inform the potential occurrence of Steller 
sea lion in Womens Bay. Although the Comprehensive Plan for the Womens 
Bay community does note that sea lions inhabit the bay (Kodiak Island 
Borough et al, 2006), the Sunaq Tribe of Kodiak suggests that Steller 
Sea Lion are rarely observed in Womens Bay. Steller sea lion are more 
abundant approximately 9 km northeast of the project area, where the 
Kodiak Ferry Terminal project was planned in 2015 (80 FR 51211, August 
24, 2015). At this location, Steller sea lions regularly haul out on 
the artificial haulout float called Dog Bay in St. Herman Harbor, near 
the Kodiak Ferry Terminal. This haulout is not designated as a major 
haulout and is not considered Steller Sea Lion critical habitat. A bi-
weekly census of Steller sea lions at the Dog Bay float, was conducted 
from November 2015 to June 2016 in association with the Kodiak Ferry 
Terminal project, revealing maximum numbers (>100) from mid-March 
through mid-June, with 5,111 total observations from November 2015 to 
June 2016 (ABR Inc, 2016). Additionally, counts conducted by Protected 
Species Observers during the Kodiak Terminal and Dock Improvements 
Project documented 6 to 114 Steller sea lion (33 on average) 
observations daily (ABR, Inc., 2016).

Harbor Seal

    The Sunaq Tribe of Kodiak indicates that large congregations 
(approximately 24 individuals) of harbor seals are frequently observed 
within the project area, concentrating near Mary's Island to dive for 
prey. During the Kodiak Ferry Terminal and Dock Improvements Project 
(approximately 6 miles northeast of the Proposed Action), 13 sightings 
of seals, with a maximum group size of 3, were reported during the 110 
days of monitoring (ABR Inc, 2016).

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Not all marine mammal species have equal 
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and 
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al. 
(2007, 2019) recommended that marine mammals be divided into hearing 
groups based on directly measured (behavioral or auditory evoked 
potential techniques) or estimated hearing ranges (behavioral response 
data, anatomical modeling, etc.). Note that no direct measurements of 
hearing ability have been successfully completed for mysticetes (i.e., 
low-frequency cetaceans). Subsequently, NMFS (2024) described updated 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges chosen based on the ~65 decibel (dB) 
threshold from composite audiograms, previous analyses in NMFS (2019, 
and/or data from Southall et al., (2007) and Southall et al., (2019). 
Marine mammal hearing groups and their associated hearing ranges are 
provided in table 4.

                  Table 4--Marine Mammal Hearing Groups
                              [NMFS, 2024]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing  range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen   7 Hz to 36 kHz.
 whales).
High-frequency (HF) cetaceans          150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
Very High-frequency (VHF) cetaceans    200 Hz to 165 kHz.
 (true porpoises, Kogia, river
 dolphins, Cephalorhynchid,
 Lagenorhynchus cruciger & L.
 australis).
Phocid pinnipeds (PW) (underwater)     40 Hz to 90 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)    60 Hz to 68 kHz.
 (sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges may not be as broad. Generalized hearing range
  chosen based on ~65 dB threshold from composite audiogram, previous
  analysis in NMFS 2018, and/or data from Southall et al., 2007;
  Southall et al., 2019. Additionally, animals are able to detect very
  loud sounds above and below that ``generalized'' hearing range.

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

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section provides a discussion of the ways in which components 
of the specified activity may impact marine mammals and their habitat. 
The Estimated Take of Marine Mammals section later in this document 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The Negligible Impact Analysis 
and Determination section considers the content of this section, the 
Estimated Take of Marine Mammals section, and the Proposed Mitigation 
section, to draw conclusions regarding the likely impacts of these 
activities on the reproductive success or survivorship of individuals 
and whether those impacts are reasonably expected to, or reasonably 
likely to, adversely affect the species or stock through effects on 
annual rates of recruitment or survival.

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

[[Page 12212]]

far (American National Standards Institute (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 activity may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals.
    In-water construction activities associated with the project would 
include impact pile driving, vibratory pile driving and removal, and 
use of DTH equipment. 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; National Institute of Occupational Safety and Health 
(NIOSH), 1998; NMFS, 2018). Non-impulsive sounds (e.g., aircraft, 
machinery operations such as drilling or dredging, vibratory pile 
driving, and active sonar systems) can be broadband, narrowband or 
tonal, brief or prolonged (continuous or intermittent), and typically 
do not have the high peak sound pressure with rapid rise/decay time 
that impulsive sounds do (ANSI, 1995; NIOSH, 1998; NMFS, 2018). The 
distinction between these two sound types is important because they 
have differing potential to cause physical effects, particularly with 
regard to hearing (e.g., Ward, 1997, in Southall et al., 2007).
    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, 2005). Vibratory hammers install piles by vibrating them and 
allowing the weight of the hammer to push them into the sediment. 
Vibratory hammers produce significantly less sound than impact hammers. 
Peak sound pressure levels (SPLs) may be 180 dB or greater, but are 
generally 10 to 20 dB lower than SPLs generated during impact pile 
driving of the same-sized pile (Oestman et al., 2009). Rise time is 
slower, reducing the probability and severity of injury, and sound 
energy is distributed over a greater amount of time (Nedwell and 
Edwards, 2002; Carlson et al., 2005).
    A DTH hammer is essentially a drill bit that drills through the 
bedrock using a rotating function like a normal drill, in concert with 
a hammering mechanism operated by a pneumatic (or sometimes hydraulic) 
component integrated into the DTH hammer to increase speed of progress 
through the substrate (i.e., it is similar to a hammer drill hand 
tool). The sounds produced by the DTH method contain both 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 continuous, non-impulsive sound source types 
simultaneously.
    The likely or possible impacts of USCG's proposed activity on 
marine mammals could involve both non-acoustic and acoustic stressors. 
Potential non-acoustic stressors could result from the physical 
presence of equipment and personnel; however, any impacts to marine 
mammals are expected to be primarily acoustic in nature. Acoustic 
stressors include effects of heavy equipment operation during pile 
installation and removal.

Acoustic Effects

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving and removal and DTH is the means by which 
marine mammals may be harassed from 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, 2019). In 
general, exposure to pile driving and DTH 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 vs. non-impulsive), the species, age and sex class (e.g., 
adult male vs. mom with calf), duration of exposure, the distance 
between the pile and the animal, received levels, behavior at time of 
exposure, and previous history with exposure (Wartzok et al., 2004; 
Southall et al., 2007). Here we discuss physical auditory effects (TSs) 
followed by behavioral effects and potential impacts on habitat.
    NMFS defines a noise-induced TS as a change, usually an increase, 
in the threshold of audibility at a specified frequency or portion of 
an individual's hearing range above a previously established reference 
level (NMFS, 2024). The amount of TS is customarily expressed in dB. A 
TS can be permanent or temporary. As described in NMFS (2024), there 
are numerous factors to consider when examining the consequence of TS, 
including, but not limited to, the signal temporal pattern (e.g., 
impulsive or non-impulsive), likelihood an individual would be exposed 
for a long enough duration or to a high enough level to induce a TS, 
the magnitude of the TS, time to recovery (seconds to minutes or hours 
to days), the frequency range of the exposure (i.e., spectral content), 
the hearing and vocalization frequency range of the exposed species 
relative to the signal's frequency spectrum (i.e., how animal uses 
sound within the frequency band of the signal; e.g., Kastelein et al., 
2014), and the overlap between the animal and the source (e.g., 
spatial, temporal, and spectral).
    Auditory Injury and Permanent Threshold Shift (PTS)--NMFS defines 
auditory injury (AUD INJ) as ``damage to the inner ear that can result 
in destruction of tissue . . . which may or may not result in PTS'' 
(NMFS, 2024). NMFS defines PTS as a permanent, irreversible increase in 
the threshold of

[[Page 12213]]

audibility at a specified frequency or portion of an individual's 
hearing range above a previously established reference level (NMFS, 
2024). Available data from humans and other terrestrial mammals 
indicate that a 40-dB TS approximates PTS onset (Ward et al., 1958, 
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 (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)--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 
(Southall et al., 2007, 2019), a TTS of 6 dB is considered the minimum 
TS clearly larger than any day-to-day or session-to-session variation 
in a subject's normal hearing ability (Schlundt et al., 2000; Finneran 
et al., 2000, 2002). As described in Finneran (2015), marine mammal 
studies have shown the amount of TTS increases with cumulative sound 
exposure level (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, 
below). For example, a marine mammal may be able to readily compensate 
for a brief, relatively small amount of TTS in a non-critical frequency 
range that takes place during a time when the animal is traveling 
through the open ocean, where ambient noise is lower and there are not 
as many competing sounds present. Alternatively, a larger amount and 
longer duration of TTS sustained during time when communication is 
critical for successful mother/calf interactions could have more 
serious impacts. We note that reduced hearing sensitivity as a simple 
function of aging has been observed in marine mammals, as well as 
humans and other taxa (Southall et al., 2007), so we can infer that 
strategies exist for coping with this condition to some degree, though 
likely not without cost.
    Many studies have examined noise-induced hearing loss in marine 
mammals (see Finneran (2015) and Southall et al. (2019) for summaries). 
TTS is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter, 2013). While experiencing TTS, the hearing 
threshold rises, and a sound must be at a higher level in order to be 
heard. In terrestrial and marine mammals, TTS can last from minutes or 
hours to days (in cases of strong TTS). In many cases, hearing 
sensitivity recovers rapidly after exposure to the sound ends. For 
cetaceans, published data on the onset of TTS are limited to captive 
bottlenose dolphin (Tursiops truncatus), beluga whale, harbor porpoise, 
and Yangtze finless porpoise (Neophocoena asiaeorientalis) (Southall et 
al., 2019). For pinnipeds in water, measurements of TTS are limited to 
harbor seals, elephant seals (Mirounga angustirostris), bearded seals 
(Erignathus barbatus) and California sea lions (Zalophus californianus) 
(Kastak et al., 1999, 2007; Kastelein et al., 2019b, 2019c, 2021, 
2022a, 2022b; Reichmuth et al., 2019; Sills et al., 2020). TTS was not 
observed in spotted (Phoca largha) and ringed (Pusa hispida) seals 
exposed to single airgun impulse sounds at levels matching previous 
predictions of TTS onset (Reichmuth et al., 2016). These studies 
examine hearing thresholds measured in marine mammals before and after 
exposure to intense or long-duration sound exposures. The difference 
between the pre-exposure and post-exposure thresholds can be used to 
determine the amount of threshold shift at various post-exposure times.
    The amount and onset of TTS depends on the exposure frequency. 
Sounds at low frequencies, well below the region of best sensitivity 
for a species or hearing group, are less hazardous than those at higher 
frequencies, near the region of best sensitivity (Finneran and 
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are 
higher compared to those in the region of best sensitivity (i.e., a low 
frequency noise would need to be louder to cause TTS onset when TTS 
exposure level is higher), as shown for harbor porpoises and harbor 
seals (Kastelein et al., 2019a, 2019c). Note that in general, harbor 
seals and harbor porpoises have a lower TTS onset than other measured 
pinniped or cetacean species (Finneran, 2015). In addition, TTS can 
accumulate across multiple exposures, but the resulting TTS 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, 
2015). This means that TTS predictions based on the total, cumulative 
SEL 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, and false killer whale 
(Pseudorca crassidens)) when a relatively loud sound was preceded by a 
warning sound. These captive animals were shown to reduce hearing 
sensitivity when warned of an impending intense sound. Based on these 
experimental observations of captive animals, the authors suggest that 
wild animals may dampen their hearing during prolonged exposures or if 
conditioned to anticipate intense sounds. Another study showed that 
echolocating animals (including odontocetes) might have anatomical 
specializations that might allow for conditioned hearing reduction and 
filtering of low-frequency ambient noise, including increased stiffness 
and control of middle ear structures and placement of inner ear 
structures (Ketten et al., 2021). Data available on noise-induced 
hearing loss for mysticetes are currently lacking (NMFS, 2018). 
Additionally, the existing marine mammal TTS data come from a limited 
number of individuals within these species.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, and there is no PTS data for cetaceans, but such 
relationships are assumed to be similar to those in humans and other 
terrestrial mammals. PTS typically occurs at exposure levels at least 
several decibels above that inducing mild TTS (e.g., a 40-dB threshold 
shift approximates PTS onset (Kryter et al., 1966; Miller, 1974), while 
a 6-dB threshold shift approximates TTS onset (Southall et al., 2007, 
2019). Based on data from terrestrial mammals, a precautionary 
assumption is that the PTS thresholds for impulsive sounds (such as 
impact pile driving pulses as received close to the source) are at 
least 6 dB higher than the TTS threshold on a peak-pressure basis and 
PTS cumulative sound exposure level thresholds are 15 to 20 dB higher 
than TTS cumulative sound exposure level thresholds (Southall et al., 
2007, 2019). Given the higher level

[[Page 12214]]

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 and DTH. For the proposed project, these activities 
would not occur at that same time and there would likely be pauses in 
activities producing the sound during each day. Given these pauses and 
the fact that many marine mammals are likely moving through the project 
areas and not remaining for extended periods of time, the potential for 
TS declines.
    Behavioral Harassment--Exposure to noise from pile driving and DTH 
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, 2019; Weilgart, 2007; Archer et al., 2010). Behavioral reactions 
can vary not only among individuals but also within an individual, 
depending on previous experience with a sound source, context, and 
numerous other factors (Ellison et al., 2012), and can vary depending 
on characteristics associated with the sound source (e.g., whether it 
is moving or stationary, number of sources, distance from the source). 
In general, pinnipeds seem more tolerant of, or at least habituate more 
quickly to, potentially disturbing underwater sound than do cetaceans, 
and generally seem to be less responsive to exposure to industrial 
sound than most cetaceans. Please see Appendices B and C of Southall et 
al. (2007) and Gomez et al. (2016) for reviews of studies involving 
marine mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2004). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure.
    As noted above, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; Wartzok et al., 2004; National Research Council (NRC), 2005). 
Controlled experiments with captive marine mammals have showed 
pronounced behavioral reactions, including avoidance of loud sound 
sources (Ridgway et al., 1997; Finneran et al., 2003). Observed 
responses of wild marine mammals to loud pulsed sound sources (e.g., 
seismic airguns) have been varied but often consist of avoidance 
behavior or other behavioral changes (Richardson et al., 1995; Morton 
and Symonds, 2002; Nowacek et al., 2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 
2005). However, there are broad categories of potential response, which 
we describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al., 2004; Goldbogen et al., 2013a, 2013b). Variations in dive behavior 
may reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. 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

[[Page 12215]]

tolerance of underwater noise when determining the potential for 
impacts resulting from anthropogenic sound exposure (e.g., Kastelein et 
al., 2001, 2005, 2006; Gailey et al., 2007). For example, harbor 
porpoise' respiration rate increased in response to pile driving sounds 
at and above a received broadband SPL of 136 dB (zero-peak SPL: 151 dB 
re 1 micropascal ([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). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from seismic surveys (Malme et al., 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; 
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). 
Longer-term displacement is possible, however, which may lead to 
changes in abundance or distribution patterns of the affected species 
in the affected region if habituation to the presence of the sound does 
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann 
et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996; Bowers et al., 2018). The result of a flight response 
could range from brief, temporary exertion and displacement from the 
area where the signal provokes flight to, in extreme cases, marine 
mammal strandings (England et al., 2001). However, it should be noted 
that response to a perceived predator does not necessarily invoke 
flight (Ford and Reeves, 2008), and whether individuals are solitary or 
in groups may influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fishes and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a 5-day period did not cause any sleep 
deprivation or stress effects.
    In 2015 and 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) across 110 monitoring 
days. 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 
3 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).
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its

[[Page 12216]]

energetic reserves sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals 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 this project based on observations of 
marine mammals during previous, similar projects in the area.
    Auditory Masking--Since many marine mammals rely on sound to find 
prey, moderate social interactions, and facilitate mating (Tyack, 
2008), noise from anthropogenic sound sources can interfere with these 
functions, but only if the noise spectrum overlaps with the hearing 
sensitivity of the receiving marine mammal (Southall et al., 2007; 
Clark et al., 2009; Hatch et al., 2012). Chronic exposure to excessive, 
though not high-intensity, noise could cause masking at particular 
frequencies for marine mammals that utilize sound for vital biological 
functions (Clark et al., 2009). Acoustic masking is when other noises 
such as from human sources interfere with an animal's ability to 
detect, recognize, or discriminate between acoustic signals of interest 
(e.g., those used for intraspecific communication and social 
interactions, prey detection, predator avoidance, navigation) 
(Richardson et al., 1995; Erbe et al., 2016). Therefore, under certain 
circumstances, marine mammals whose acoustical sensors or environment 
are being severely masked could also be impaired from maximizing their 
performance fitness in survival and reproduction. The ability of a 
noise source to mask biologically important sounds depends on the 
characteristics of both the noise source and the signal of interest 
(e.g., signal-to-noise ratio, temporal variability, direction), in 
relation to each other and to an animal's hearing abilities (e.g., 
sensitivity, frequency range, critical ratios, frequency 
discrimination, directional discrimination, age or TTS hearing loss), 
and existing ambient noise and propagation conditions (Hotchkin and 
Parks, 2013).
    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 USCG project site may be 
exposed to anthropogenic noise which may be a source of masking. 
Vocalization changes may result from a need to compete with an increase 
in background noise and include increasing the source level, modifying 
the frequency, increasing the call repetition rate of vocalizations, or 
ceasing to vocalize in the presence of increased noise (Hotchkin and 
Parks, 2013). For example, in response to loud noise, beluga whales may 
shift the frequency of their echolocation clicks to prevent masking by 
anthropogenic noise (Tyack, 2000; Eickmeier and Vallarta, 2022).
    Masking 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 
site within the range of noise levels elevated above the acoustic 
criteria. We recognize that pinnipeds in the water could be exposed to 
airborne sound that may result in behavioral harassment when looking 
with their heads above water. Most likely, airborne sound would cause 
behavioral responses similar to those discussed above in relation to 
underwater sound. For instance, anthropogenic sound could cause hauled-
out pinnipeds to exhibit changes in their normal behavior, such as 
reduction in vocalizations, or cause them to temporarily abandon the 
area and move further from the source. However, these animals would 
previously have been ``taken'' because of exposure to underwater sound 
above the behavioral harassment thresholds, which are in all cases 
larger than those associated with airborne sound. Thus, the behavioral 
harassment of these animals is already accounted for in these estimates 
of potential take. Therefore, 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

[[Page 12217]]

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 and their 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 vibratory and impact pile driving and DTH, elevated 
levels of underwater noise would ensonify a portion of Womens Bay, 
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 and vibroflots 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.
    In-water Construction Effects on Potential Foraging Habitat--The 
proposed activities would not result in permanent impacts to habitats 
used directly by marine mammals. The areas likely impacted by the 
proposed action are relatively small compared to the total available 
habitat in the Gulf of Alaska. 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). Marine mammal prey varies by species, season, and 
location and, for some, is not well documented. Here, we describe 
studies regarding the effects of noise on known marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009). 
Depending on their hearing anatomy and peripheral sensory structures, 
which vary among species, fishes hear sounds using pressure and 
particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    Fish react to sounds which are especially strong and/or 
intermittent low-frequency sounds, and behavioral responses such as 
flight or avoidance are the most likely effects. Short duration, sharp 
sounds can cause overt or subtle changes in fish behavior and local 
distribution. The reaction of fish to noise depends on the 
physiological state of the fish, past exposures, motivation (e.g., 
feeding, spawning, migration), and other environmental factors. 
Hastings and Popper (2005) identified several studies that suggest fish 
may relocate to avoid certain areas of sound energy. Additional studies 
have documented effects of pile driving on fish, although several are 
based on studies in support of large, multiyear bridge construction 
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 
2009). Several studies have demonstrated that impulse sounds might 
affect the distribution and behavior of some fishes, potentially 
impacting foraging opportunities or increasing energetic costs (e.g., 
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al., 
1992; Santulli et al., 1999; Paxton et al., 2017). However, some 
studies have shown no or slight reaction to impulse sounds (e.g., Pena 
et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott 
et al., 2012). More commonly, though, the impacts of noise on fish are 
temporary.
    SPLs of sufficient strength have been known to cause AUD INJ, non-
AUD INJ, and mortality to fish. However, in most fish species, hair 
cells in the ear continuously regenerate and loss of auditory function 
likely is restored when damaged cells are replaced with new cells. 
Halvorsen et al. (2012a) showed that a TTS of 4-6 dB was recoverable 
within 24 hours for one species. Impacts would be most severe when the 
individual fish is close to the source and when the duration of 
exposure is long. Injury caused by barotrauma can range from slight to 
severe and can cause death, and is most likely for fish with swim 
bladders. Barotrauma injuries have been documented during controlled 
exposure to impact pile driving (Halvorsen et al., 2012b; Casper et 
al., 2013).
    In year 1, the greatest potential impact to fishes during 
construction would occur during impact pile installation of 24-in and 
42-in steel pipe piles, and 24-in precast square concrete, which is 
estimated to occur on up to 44 days for a maximum of 14,400 strikes per 
day, and DTH installation of 19-42-inch steel piles, which is estimated 
to occur up to 55 days for a maximum of 180,000 strikes per day. In 
year 2, the greatest potential impact to fishes during construction 
would occur during impact pile installation of 24-in through 42-in 
steel pipe piles, which is estimated to occur on up to 17 days for a 
maximum of 14,400 strikes per day, and DTH installation of 19-24 inch 
steel piles, which is estimated to occur up to 24 days for a maximum of 
180,000 strikes per day. In-water construction activities would only 
occur during daylight hours, allowing fish to forage and transit the 
project area in the evening. Vibratory pile driving would possibly 
elicit behavioral reactions from fishes such as temporary avoidance of 
the area but is unlikely to cause injuries to fishes or have persistent 
effects on local fish populations.
    The most likely impact to fishes from pile driving and DTH 
activities in the project area 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 to fish would be temporary and

[[Page 12218]]

limited to the duration of sound-generating activities.
    In summary, given the short daily duration of sound associated with 
individual 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. Any behavioral avoidance by 
fish of the disturbed area would still leave significantly large areas 
of fish and marine mammal foraging habitat in the nearby vicinity. 
Thus, we conclude that impacts of the specified activity are not likely 
to have more than short-term adverse effects on any prey habitat or 
populations of prey species. Further, any impacts to marine mammal 
habitat are not expected to result in significant or long-term 
consequences for individual marine mammals, or to contribute to adverse 
impacts on their populations.

Estimated Take of Marine Mammals

    This section provides an estimate of the number of incidental takes 
proposed for authorization through the IHAs, 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 AUD INJ 
(Level A harassment) to result, primarily for very high frequency 
species, phocids, and otariids, because predicted AUD INJ zones are 
larger than are observable. AUD INJ is unlikely to occur for high-
frequency species and mysticetes. The proposed mitigation and 
monitoring measures are expected to minimize the severity of the taking 
to the extent practicable.
    As described previously, no serious injury or mortality is 
anticipated or proposed to be authorized for this activity. Below we 
describe how the proposed take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) acoustic criteria above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed or incur some degree of injury; (2) the area or volume of 
water that will be ensonified above these levels in a day; (3) the 
density or occurrence of marine mammals within these ensonified areas; 
and, (4) the number of days of activities. We note that while these 
factors can contribute to a basic calculation to provide an initial 
prediction of potential takes, additional information that can 
qualitatively inform take estimates is also sometimes available (e.g., 
previous monitoring results or average group size). Below, we describe 
the factors considered here in more detail and present the proposed 
take estimates.

Acoustic Criteria

    NMFS recommends the use of acoustic criteria that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur AUD INJ of some degree (equated to 
Level A harassment). We note that the criteria for AUD INJ, as well as 
the names of two hearing groups, have been recently updated (NMFS, 
2024) as reflected below in the Level A harassment section.
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007, 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 (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.
    USCG's proposed activity includes the use of continuous (vibratory 
pile driving and DTH) and impulsive (impact pile driving and DTH) 
sources, and therefore the RMS SPL thresholds of 120 AND/OR 160 dB re 1 
[mu]Pa are applicable.
    Level A Harassment--NMFS' 2024 Updated Technical Guidance for 
Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing 
(Version 3.0) (Updated Technical Guidance, 2024) identifies dual 
criteria to assess AUD INJ (Level A harassment) to five different 
underwater marine mammal groups (based on hearing sensitivity) as a 
result of exposure to noise from two different types of sources 
(impulsive or non-impulsive). USCG's proposed activity includes the use 
of impulsive (impact pile driving and DTH) and non-impulsive (vibratory 
pile driving and DTH) sources.
    The 2024 Updated Technical Guidance criteria include both updated 
thresholds and updated weighting functions for each hearing group. 
These thresholds criteria thresholds are provided in the table below. 
The references, analysis, and methodology used in the development of 
the criteria thresholds, as well as the detailed description of the 
updated weighting

[[Page 12219]]

functions, are described in NMFS' 202418 Updated Technical Guidance, 
which may be accessed at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

              Table 5--Thresholds Identifying the Onset of AUD INJ Based on 2024 Technical Guidance
----------------------------------------------------------------------------------------------------------------
                                                       AUD INJ onset thresholds * (received level)
             Hearing group             -------------------------------------------------------------------------
                                                Impulsive                          Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans..........  Cell 1: L0-pk,flat: 222    Cell 2: LE,LF,24h: 197 dB.
                                         dB; LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans.........  Cell 3: L0-pk,flat: 230    Cell 4: LE,HF,24h: 201 dB.
                                         dB; LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans...  Cell 5: L0-pk,flat: 202    Cell 6: LE,VHF,24h: 181 dB.
                                         dB; LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater)....  Cell 7: L0-pk.flat: 223    Cell 8: LE,PW,24h: 195 dB.
                                         dB; LE,PW,24h: 183 dB.
Otariid Pinnipeds (OW) (Underwater)...  Cell 9: L0-pk,flat: 230    Cell 10: LE,OW,24h: 199 dB.
                                         dB; LE,OW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating AUD
  INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds
  associated with impulsive sounds, these thresholds are recommended for consideration.
Note: Peak sound pressure level (L0-pk) has a reference value of 1 [mu]Pa, and weighted cumulative sound
  exposure level (LE,) has a reference value of 1[mu]Pa\2\s. In this table, thresholds are abbreviated to be
  more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
  is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
  hearing range of marine mammals (i.e., 7 Hz to 165 kHz). The subscript associated with cumulative sound
  exposure level thresholds indicates the designated marine mammal auditory weighting function (LF, HF, and VHF
  cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The weighted
  cumulative sound exposure level thresholds could be exceeded in a multitude of ways (i.e., varying exposure
  levels and durations, duty cycle). When possible, it is valuable for action proponents to indicate the
  conditions under which these thresholds will be exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that are used in estimating the area ensonified above the 
acoustic thresholds, including source levels and transmission loss 
coefficient.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., vibratory pile driving and 
removal, impact pile driving, and DTH).
    The project includes vibratory pile installation and removal, 
impact pile driving, and DTH. Source levels for these activities are 
based on reviews of measurements of the same or similar types and 
dimensions of pile available in the literature. Source levels for each 
pile size and activity each year are presented in tables 6 and 7. 
Source levels for vibratory installation and removal of piles of the 
same diameter are assumed to be the same.

  Table 6--Year 1 Estimates of Mean Underwater Sound Levels * Generated During Vibratory, Impact, and DTH Pile
                                     Installation and Vibratory Pile Removal
----------------------------------------------------------------------------------------------------------------
            Method                  Pile type      Pile size    dB RMS    dB peak     dB SEL       Reference
----------------------------------------------------------------------------------------------------------------
Vibratory installation and      Timber...........         14        160        N/A        N/A  Greenbusch 2018.
 extraction.
                                                          24        160        N/A        N/A  Greenbusch 2018.
                                Steel Pipe.......         12        155        N/A        N/A  CalTrans 2015.
                                                          14        154        N/A        N/A  CalTrans 2020.
                                                          24        153        N/A        N/A  CalTrans 2020.
                                                          36        170        N/A        N/A  CalTrans 2015.
                                                          42        169        N/A        N/A  Illingworth and
                                                                                                Rodkin 2019.
                                Steel Pipe filled         24        163        N/A        N/A  NAVFAC SW 2022.
                                 with Concrete.
                                Precast square            24        163        N/A        N/A  NAVFAC SW 2022.
                                 concrete.
                                Stone column via          30        159        N/A        N/A  CalTrans 2020.
                                 Vibroflot.
Impact........................  Steel Pipe.......         24        190        203        177  CalTrans 2015.
                                                          42        192        213        179  CalTrans 2020.
                                Precast Square         ** 24        176        195        164  CalTrans
                                 Concrete.                                                      (measured at
                                                                                                17.5 m).
DTH...........................  Steel Pipe.......      19-24        167        184        159  Heyvaert & Reyff
                                                                                                2021.
                                                       25-42        174        194        164  Denes et al.,
                                                                                                2019; Heyvaert,
                                                                                                2019; Reyff,
                                                                                                2020.
----------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; rms = root mean square; SEL = sound exposure level.
* All sound levels are referenced at 10 m unless otherwise indicated.
** Sound levels for impact installation of 24-inch precast square concrete are measured at 17.5 m.


  Table 7--Year 2 Estimates of Mean Underwater Sound Levels * Generated During Vibratory, Impact, and DTH Pile
                                     Installation and Vibratory Pile Removal
----------------------------------------------------------------------------------------------------------------
            Method                  Pile type      Pile size    dB RMS    dB peak     dB SEL       Reference
----------------------------------------------------------------------------------------------------------------
Vibratory installation and      Steel Pipe.......         24        153        N/A        N/A  CalTrans 2020.
 extraction.
                                                          30        159        N/A        N/A  CalTrans 2020.
                                                          36        170        N/A        N/A  CalTrans 2015.
                                                          42        169        N/A        N/A  Illingworth and
                                                                                                Rodkin 2019.
Impact........................  Steel Pipe.......         24        190        203        177  CalTrans 2015.
                                                          30        190        210        177  CalTrans 2020.
                                                          36        193        210        183  CalTrans 2020.
                                                          42        192        213        179  CalTrans 2020.
DTH...........................  Steel Pipe.......      19-24        167        184        159  Heyvaert & Reyff
                                                                                                2021.

[[Page 12220]]

 
                                                       25-42        174        194        164  Denes et al.,
                                                                                                2019; Heyvaert,
                                                                                                2019; Reyff,
                                                                                                2020.
----------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; rms = root mean square; SEL = sound exposure level.
* All sound levels are referenced at 10 m.

    DTH systems have both continuous, non-impulsive, and impulsive 
components as discussed in the Description of Sound Sources section 
above. When evaluating Level B harassment, NMFS recommends treating DTH 
as a continuous source and applying RMS SPL thresholds of 120 dB re 1 
[mu]Pa. When evaluating Level A harassment, NMFS recommends treating 
DTH as an impulsive source. NMFS (2022) guidance on DTH systems 
(https://media.fisheries.noaa.gov/2022-11/PUBLIC%20DTH%20Basic%20Guidance_November%202022.pdf) recommends source 
levels for DTH systems; NMFS has applied those levels in our analysis 
(see tables 6 and 7 for NMFS' proposed source levels).
    TL is the decrease in acoustic intensity as an acoustic pressure 
wave propagates out from a source. TL parameters vary with frequency, 
temperature, sea conditions, current, source and receiver depth, water 
depth, water chemistry, and bottom composition and topography. The 
general formula for underwater TL is:

TL = B x Log10 (R1/R2),

Where:

TL = transmission loss in dB
B = transmission loss coefficient
R1 = the distance of the modeled SPL from the driven 
pile, and
R2 = the distance from the driven pile of the initial 
measurement

    Absent site-specific acoustical monitoring with differing measured 
TL, a practical spreading value of 15 is used as the TL coefficient in 
the above formula. Site-specific TL data for the Womens Bay are not 
available; therefore, the default coefficient of 15 is used to 
determine the distances to the Level A harassment and Level B 
harassment thresholds.
    The ensonified area associated with Level A harassment is more 
technically challenging to predict due to the need to account for a 
duration component. Therefore, NMFS developed an optional User 
Spreadsheet tool to accompany the 2024 Updated Technical Guidance that 
can be used to relatively simply predict an isopleth distance for use 
in conjunction with marine mammal density or occurrence to help predict 
potential takes. We note that because of some of the assumptions 
included in the methods underlying this optional tool, we anticipate 
that the resulting isopleth estimates are typically going to be 
overestimates of some degree, which may result in an overestimate of 
potential take by Level A harassment. However, this optional tool 
offers the best way to estimate isopleth distances when more 
sophisticated modeling methods are not available or practical. For 
stationary sources such as pile driving 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 AUD INJ, which includes but is not limited to 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 1, 2, the sound levels are presented in tables 6 and 7, and the 
resulting estimated isopleths and total ensonified areas are reported 
below in tables 8 and 9.

  Table 8--Projected Distances to Level A and Level B Harassment Isopleths (m) and Associated Areas \1\ (km\2\) by Marine Mammal Hearing Group--Year 1
                                                                       Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Level B
                 Pile type                   Pile size      LF         HF            VHF                 PW                 OW             harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation and Extraction:
    Timber.................................         14       17.7        6.8               14.4               22.7                7.6   \2\ 4,642 (7.52)
                                                    24       17.7        6.8               14.4               22.7                7.6   \2\ 4,642 (7.52)
    Steel..................................         12       18.2        3.1                6.7               10.5                3.5              2,154
                                                    14        7.0        2.7                5.7                9.0                3.0              1,848
                                                    24        4.3        1.6                3.5                5.5                1.9              1,585
                                                    36       58.3       22.4               47.6               75.0               25.3  \2\ 21,544 (7.52)
                                                    42       50.0       19.2               40.8               64.3               21.7  \2\ 18,478 (7.52)
    Steel/Concrete.........................         24         28       10.7               22.9               36.0               12.1   \2\ 7,356 (7.52)
    Precast Concrete.......................         24       19.9        7.6               16.3               25.6                8.6   \2\ 7,356 (7.52)
    Vibroflot..............................         30         26         10               21.2               33.5               11.3              3,981
Impact Pile Driving:
    Steel..................................         24    1,935.4      246.9            2,995.1            1,719.3       640.9 (1.01)              1,000
                                                    42    3,187.1      406.6            4,932.1            2,831.3       1,055 (1.32)              1,359
    Precast Concrete.......................         24      557.7       71.2              863.1              495.5              184.7                204
Down-the-hole Drilling:
    Steel..................................      19-24      796.8      101.7     1,233.0 (1.49)       707.8 (1.07)       263.8 (0.32)  \2\ 13,594 (7.52)
                                                 25-42    1,716.6      219.0     2,656.5 (4.17)     1,525.0 (1.83)       568.4 (0.91)  \2\ 39,811 (7.52)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Abbreviations: LF = low-frequency cetaceans, HF = high-frequency cetaceans, VHF = very high-frequency cetaceans, PW = phocid pinnipeds in water, OW =
  otariid pinnipeds in water.
\1\ Only harassment areas used in take estimate calculations are presented.
\2\ Total harassment areas are the same despite having varying calculated isopleths because the maximum distance is truncated by the other side of
  Womens Bay.


[[Page 12221]]


  Table 9--Projected Distances to Level A and Level B Harassment Isopleths (m) and Associated Areas \1\ (km\2\) by Marine Mammal Hearing Group--Year 2
                                                                       Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Level B
                 Pile type                   Pile size      LF         HF            VHF                 PW                 OW             harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation and Extraction:
    Steel..................................         24        4.3        1.6                3.5                5.5                1.9              1,585
                                                    30       10.8        4.1                8.8               13.9                4.7              3,981
                                                    36       58.3       22.4               47.6               75.0               25.3  \2\ 21,544 (7.52)
                                                    42       50.0       19.2               40.8               64.3               21.7  \2\ 18,478 (7.52)
Impact Pile Driving:
    Steel..................................         24    1,935.4      246.9            2,995.1            1,719.3       640.9 (1.01)              1,000
                                                    30    1,935.4      246.9            2,995.1            1,719.3       640.9 (1.01)              1,000
                                                    36    3,710.0      473.4        \1\ 5,741.3            3,295.9     1,228.6 (1.49)              1,585
                                                    42    3,187.1      406.6        \1\ 4,932.1            2,831.3       1,055 (1.32)              1,359
Down-the-hole Drilling:
    Steel..................................      19-24      796.8      101.7     1,233.0 (1.49)       707.8 (1.07)       263.8 (0.32)  \2\ 13,594 (7.52)
                                                 25-42    1,716.6      219.0     2,656.5 (4.17)     1,525.0 (1.83)       568.4 (0.91)  \2\ 39,811 (7.52)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Abbreviations: LF = low-frequency cetaceans, HF = high-frequency cetaceans, VHF = very high-frequency cetaceans, PW = phocid pinnipeds in water, OW =
  otariid pinnipeds in water.
\1\ Only harassment areas used in take estimate calculations are presented.
\2\ Total harassment areas are the same despite having varying calculated isopleths because the maximum distance is truncated by the other side of
  Womens Bay.

    Level A harassment zones are typically smaller than Level B 
harassment zones. However, in rare cases such as during impact pile 
driving of 24, 30, 36 and 42-inch steel piles and 24-inch precast 
concrete piles, the calculated Level A harassment isopleth is greater 
than the calculated Level B harassment isopleth for low frequency 
cetaceans, very high-frequency cetaceans, and phocids (tables 8 and 9). 
Calculation of Level A harassment isopleths include a duration 
component, which in the case of impact pile driving, is estimated 
through the total number of daily strikes and the associated pulse 
duration. For a stationary sound source such as impact pile driving, we 
assume here that an animal is exposed to all of the strikes expected 
within a 24-hour period. Calculation of a Level B harassment zone does 
not include a duration component. Depending on the duration included in 
the calculation, the calculated Level A harassment isopleths can be 
larger than the calculated Level B harassment isopleth for the same 
activity. This is the case for this project for low frequency 
cetaceans, very high frequency cetaceans, and phocids during impact 
pile driving of 24 and 42-inch steel piles and 24-inch precast concrete 
piles in year 1, and during impact pile driving of 24, 30, 36, and 42-
inch steel piles in year 2.

Marine Mammal Occurrence and Take Estimation

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information which 
will inform the take calculations. Additionally, we describe how the 
occurrence information is synthesized to produce a quantitative 
estimate of the take that is reasonably likely to occur and proposed 
for authorization. Available information regarding marine mammal 
occurrence in the vicinity of the project area includes site-specific 
and nearby survey information and knowledge from local tribes. Data 
sources consulted included: (1) Anecdotal input from the Sunaq Tribe of 
Kodiak's Natural Resources Director (Van Daele, personal communication, 
2024), (2) Protected Species Observer (PSO) monitoring completed in 
Near Island Channel on 110 days between November 205 and June 2016 
during the Kodiak Ferry Terminal and Dock Improvements Project, 
approximately 9 km northeast of Womens Bay (ABR Inc., 2016), (3) PSO 
monitoring completed in Womens Bay on 12 days in March 2018 during the 
USCG Cargo Dock Repair project (USCG 2018), (4) Surveys described in 
Cetaceans of Southeast Alaska: Distribution and Seasonal Occurrence 
(group size estimates for Dall's porpoise) (Dalheim et al., 2009), and 
(5) Alaska Wildlife Notebook Series (group size estimates for low-
frequency cetaceans) (Frost and Karpovich, 2008; Clark, 2008; Guerrero, 
2008).
    In its initial application, the USCG estimated take using data 
sources 2, 4, and the U.S. Navy's Marine Species Density Database. NMFS 
recommended the inclusion of the data sources listed above and the 
exclusion of the density estimates given that they were calculated for 
offshore areas; USCG concurred, and updated its application to reflect 
NMFS' recommended method. Therefore, to estimate take, NMFS referred to 
the sets listed above to estimate a daily occurrence probability in 
which groups per day and group size are estimated for each species and 
multiplied by the number of days of each type of pile driving activity. 
For species that are unlikely to occur in the project area, but for 
which there is some potential (low frequency cetaceans and Pacific 
white-sided dolphin), NMFS predicts that one group of each species may 
occur in the project area during each project year. NMFS used the 
following equation to estimate take by Level B harassment for all 
species other than low-frequency cetaceans and Pacific white-sided 
dolphin:

Take by Level B harassment = group size x groups per day x days of pile 
driving activities in which the Level B harassment isopleths are larger 
than the Level A harassment isopleths

    For activities where the Level A harassment isopleth is larger than 
the Level B harassment isopleth for a given hearing group, NMFS 
conservatively assumes that all take from that activity of that hearing 
group would be by Level A harassment, as described further below.
    The USCG proposes to implement shutdown zones that meet or exceed 
the Level A harassment isopleths: (1) for all hearing groups during all 
vibratory pile driving activities; (2) for low and high-frequency 
cetaceans during impact pile driving and DTH activities (3) for 
otariids, during impact installation of 24-inch pre-cast concrete and 
DTH installation of 19-24-inch Steel piles. For other hearing groups 
and activity combinations, the Level A harassment zone would exceed the 
shutdown zone, as described in more detail below.
    For activities and hearing groups where the Level A harassment 
isopleth is larger than the Level B harassment isopleth, NMFS used the 
following equation to estimate take by Level A harassment:

Group size x groups per day x days of pile driving activities in which 
the Level A harassment isopleth is larger than the Level B isopleth


[[Page 12222]]


    For very-high frequency cetaceans and phocids, the calculated Level 
A harassment zones exceed the proposed shutdown zones during impact 
installation of all piles. For otariids, the calculated Level A 
harassment zones exceed the proposed shutdown zones during impact 
installation of all piles except for 24-inch pre-cast concrete and DTH 
of 19-24-inch steel.
    For activities and hearing groups where the Level A harassment 
isopleth is larger than the shutdown zone but smaller than the Level B 
harassment zone, we proportionally compared, by hearing group, the 
portion of the largest Level A harassment area (km\2\) that exceeds the 
planned shutdown zone area (km\2\) to the area (km\2\) of the Level B 
harassment zone for that activity and pile type. NMFS then multiplied 
this proportion by the group size, daily sightings, and number of 
construction days, according to the following equation:

Take by Level A harassment = Level A harassment area* (km\2\)/Level B 
harassment area (km\2\) x group size x groups per day x days of pile 
driving.
    * The Level A harassment area refers to the Level A harassment 
isopleth minus the proposed shutdown zone for that activity and hearing 
group.
Gray Whale
    Gray whales are solitary animals often traveling alone or in small 
groups of three (Frost and Karpovich, 2008). They are rare in the 
project area. Therefore, NMFS predicts that one group of three gray 
whales could occur within the Level B harassment zone during each year 
of the project and proposes to authorize three takes by Level B 
harassment for gray whale in year 1 and three takes by Level B 
harassment for gray whale in year 2.
    Takes by Level A harassment for gray whale are not requested nor 
are they proposed for authorization during either project year.
Fin Whale
    Fin whale are typically observed in groups of 6 to 10 animals 
(Clark, 2008a). They are rare in the project area. Therefore NMFS 
predicts that one group of six fin whale could occur within the Level B 
harassment zone across the project, each year, to account for the small 
but unlikely possibility that this species could occur within the 
project area. Therefore, NMFS proposes to authorize six takes by Level 
B harassment for fin whale in year 1 and six takes by Level B 
harassment for fin whale in year 2.
    Takes by Level A harassment for fin whale are not requested nor are 
they proposed for authorization either project year.
Humpback Whale
    Humpback whale are often observed alone or in small groups that 
persist for only a few hours (Zimmerman and Karpovich, 2008). They are 
rare in the project area. Therefore NMFS predicts that one group of two 
humpback whale could occur within the Level B harassment zone across 
the project, each year, to account for the small but unlikely 
possibility that this species could occur within the project area. 
Therefore, NMFS proposes to authorize two takes by Level B harassment 
for humpback whale (any stock) in year 1 and two takes by Level B 
harassment for humpback whale (any stock) in year 2.
    Takes by Level A harassment for humpback whale are not requested 
nor are they proposed for authorization either project year.
Minke Whale
    Minke whale are often observed in groups of two or three (Guerrero, 
2008). While rare, it is possible that minke whale could occur within 
the project area. Therefore, NMFS predicts that one group of two minke 
whale could occur within the Level B harassment zone across the 
project, each year, to account for the small but unlikely possibility 
that this species could occur within the project area. Therefore, NMFS 
proposes to authorize three takes by Level B harassment for minke whale 
in year 1 and three takes by Level B harassment for minke whale in year 
2.
    Takes by Level A harassment for minke whale are not requested nor 
are they proposed for authorization either project year.
Killer Whale
    Based on the known occurrence of killer whale and confirmation of 
sightings within the general vicinity of Womens Bay, it is likely that 
both resident and transient killer whale would occur within the project 
area. Based on local sightings, NMFS predicts one group of seven killer 
whales could occur within the Level B harassment zone every 1 
construction month (30 days). In year 1, for this species, the duration 
of the construction for which the Level B zone is larger than the Level 
A zone is 264 days (8.8 is the basic 30 day period that corresponds to 
1 construction months). This results in 62 takes by Level B harassment 
of killer whale (7 killer whale x 8.8 30-day periods) across any stock.
    In year 2, for this species, the duration of the construction for 
which the Level B zone is larger than the Level A zone is 76 days (2.5 
is the basic 30 day period that corresponds to 1 construction months). 
This results in 18 takes by Level B harassment of killer whale (7 
killer whale x 2.5 30-day periods) across any stock.
    Takes by Level A harassment for killer whale are not requested nor 
are they proposed for authorization either project year.
Pacific White-Sided Dolphin
    Pacific white-sided dolphin group sizes are usually between 10 and 
100 animals. Due to the shallow, enclosed nature of Womens Bay it would 
be a rare, though possible, occurrence for individuals to enter the 
action area. Therefore, NMFS predicts that one group of 10 pacific 
white-sided dolphin could occur within the Level B harassment zone 
across the project, each year, to account for the small but unlikely 
possibility that this species could occur within the project area. 
Therefore, NMFS proposes to authorize 10 takes by Level B harassment 
for pacific white-sided dolphin in year 1 and 3 takes by Level B 
harassment for pacific white-sided dolphin in year 2.
    Takes by Level A harassment for Pacific white-sided dolphin are not 
requested nor are they proposed for authorization either project year.
Dall's Porpoise
    Information regarding group size near Kodiak Island is limited; 
however, studies conducted along the inland waters of southeast Alaska 
indicate average group sizes ranged from 2.51 to 5.46 individuals 
during surveys conducted from 1991 to 2007 (Dahlheim et al., 2009). 
While there are no known sightings in Womens Bay, because Dall's 
porpoise have been documented around Kodiak Island and have been known 
to occur in nearshore habitats, NMFS predicts that one group of four 
Dall's porpoise could occur within the Level B harassment zone every 1 
construction month (30 days) each year.
    In year 1, the duration of the construction for which the Level B 
harassment zone is larger than the Level A harassment zone is 257 days 
(8.6 is the basic 30 day period that corresponds to 1 construction 
months). This results in 35 takes by Level B harassment of Dall's 
porpoise (4 Dall's porpoise x 8.6 30-day periods).
    During all DTH activities, the Level A harassment zone is larger 
than the shutdown zone, but smaller than the Level B harassment zone. 
As such it is possible that Dall's porpoise may enter

[[Page 12223]]

the Level A harassment zone and stay long enough to incur AUD INJ 
before exiting. For DTH of 19-24-in steel piles, the ratio of the Level 
A harassment area that exceeds the shutdown zone to the Level B 
harassment area is 0.14. This activity is predicted to take place on 7 
construction days (7 construction days / 30 days = 0.23 30-day 
construction periods). For DTH of 24-42-in steel piles, the ratio of 
the Level A harassment area that exceeds the shutdown zone to the Level 
B harassment area is 0.50. This activity is predicted to take place on 
48 construction days (48 construction days / 30 days = 1.6 30-day 
construction periods). As such, 4 takes by Level A harassment are 
proposed for authorization [(0.14 x 1 group x 4 Dall's porpoise x 0.23 
30-day construction periods) + (0.5 x 1 group x 4 Dall's porpoises x 
1.6 30-day construction periods) = 3.3 takes by Level A harassment].
    During all impact pile driving, the Level A harassment zone is 
larger than the Level B harassment zone. These activities are predicted 
to take place on 44 construction days (44 construction days / 30 days = 
1.5 30-day construction periods). Estimated take by Level A harassment 
for these activities result in 2 based on 1 group x 4 Dall's porpoise x 
1.5 30 day construction periods (1 x 4 x 1.5 = 6 takes by Level A 
harassment).
    Takes by Level B harassment were modified to deduct the proposed 
amount of take by Level A harassment estimated in cases where the Level 
A zone is smaller than the Level B zone (i.e., 35 total exposures-4 
takes by Level A harassment estimated during DTH activities = 31 takes 
by Level B harassment). Therefore, for Dall's porpoise, NMFS proposes 
to authorize 10 takes by Level A harassment (4 takes + 6 takes) and 31 
takes by Level B harassment, for a total of 41 takes in year 1.
    In year 2, the duration of the construction for which the Level B 
harassment zone is larger than the Level A harassment zone is 76 days 
(2.5 is the basic 30 day period that corresponds to 1 construction 
months). This results in 10 takes by Level B harassment of Dall's 
porpoise (4 Dall's porpoise x 2.5 30-day periods).
    During all DTH activities, the Level A harassment zone is larger 
than the shutdown zone, but smaller than the Level B harassment zone. 
As such it is possible that Dall's porpoise may enter the Level A 
harassment zone and stay long enough to incur AUD INJ before exiting. 
For DTH of 19-24-in steel piles, the ratio of the Level A harassment 
area that exceeds the shutdown zone to the Level B harassment area is 
0.14. This activity is predicted to take place on 6 construction days 
(6 construction days / 30 days = 0.2 30-day construction periods). For 
DTH of 24-42-in steel piles, the ratio of the Level A harassment area 
that exceeds the shutdown zone to the Level B harassment area is 0.50. 
This activity is predicted to take place on 18 construction days (18 
construction days / 30 days = 0.6 30-day construction periods). As 
such, two takes by Level A harassment are proposed for authorization 
[(0.14 x 1 group x 4 Dall's porpoise x 0.2 30-day construction periods) 
+ (0.5 x 1 group x 4 Dall's porpoises x 0.6 30-day construction 
periods) = 1.3 takes by Level A harassment].
    During all impact pile driving, the Level A harassment zone is 
larger than the Level B harassment zone. These activities are predicted 
to take place on 17 construction days (17 construction days / 30 days = 
0.6 30-day construction periods). Estimated take by Level A harassment 
for these activities result in three based on 1 group x 4 Dall's 
porpoise x 0.6 30 day construction periods (1 x 4 x 0.6 = 2.4 takes by 
Level A harassment).
    Takes by Level B harassment were modified to deduct the proposed 
amount of take by Level A harassment estimated in cases where the Level 
A harassment zone is smaller than the Level B zone (i.e., 10 total 
exposures-2 takes by Level A harassment estimated during DTH activities 
= 8 takes by Level B harassment). Therefore, for Dall's porpoise, NMFS 
proposes to authorize 5 takes by Level A harassment (2 takes + 3 takes) 
and 8 takes by Level B harassment, for a total of 13 takes in year 1.
Harbor Porpoise
    Harbor porpoises are known to frequent nearshore habitats, 
including bays, and have been documented in bays near the project area 
(Van Daele, 2024, personal communication; therefore, harbor porpoises 
may intermittently enter the project area. Based on input from the 
Sunaq tribe, NMFS predicts one group of six harbor porpoises could 
occur within the Level B harassment zone every 1 construction month (30 
days) each year (Van Deale, 2024, personal communication).
    In year 1, the duration of the construction for which the Level B 
zone is larger than the Level A zone is 257 days (8.6 is the basic 30 
day period that corresponds to 1 construction months). This results in 
52 takes by Level B harassment of harbor porpoise (6 harbor porpoise x 
8.6 30-day periods).
    During all DTH activities, the Level A harassment zone is larger 
than the shutdown zone, but smaller than the Level B zone. As such it 
is possible that harbor porpoise may enter the Level A harassment zone 
and stay long enough to incur AUD INJ before exiting. For DTH of 19-24-
in steel piles, the ratio of the Level A harassment area that exceeds 
the shutdown zone to the Level B harassment area is 0.14. This activity 
is predicted to take place on 7 construction days (7 construction days 
/ 30 days = 0.23 30-day construction periods). For DTH of 24-42-in 
steel piles, the ratio of the Level A harassment area that exceeds the 
shutdown zone to the Level B harassment area is 0.50. This activity is 
predicted to take place on 48 construction days (48 construction days / 
30 days = 1.6 30-day construction periods). As such, five takes by 
Level A harassment are proposed for authorization [(0.14 x 1 group x 6 
harbor porpoise x 0.23 30-day construction periods) + (0.5 x 1 group x 
6 harbor porpoises x 1.6 30-day construction periods) = 5 takes by 
Level A harassment].
    During all impact pile driving, the Level A harassment zone is 
larger than the Level B harassment zone. These activities are predicted 
to take place on 44 construction days (44 construction days / 30 days = 
1.5 30-day construction periods). Estimated take by Level A harassment 
for these activities result in nine based on 1 group x 6 harbor 
porpoise x 1.5 30 day construction periods (1 x 6 x 1.5 = 8.8 takes by 
Level A harassment).
    Takes by Level B harassment were modified to deduct the proposed 
amount of take by Level A harassment estimated in cases where the Level 
A harassment zone is smaller than the Level B harassment zone (i.e., 52 
total exposures-5 takes by Level A harassment estimated during DTH 
activities = 47 takes by Level B harassment). Therefore, for harbor 
porpoise, NMFS proposes to authorize 14 takes by Level A harassment (5 
takes + 9 takes) and 47 takes by Level B harassment, for a total of 61 
takes in year 1.
    In year 2, the duration of the construction for which the Level B 
harassment zone is larger than the Level A harassment zone is 76 days 
(2.5 is the basic 30 day period that corresponds to 1 construction 
months). This results in 16 takes by Level B harassment of harbor 
porpoise (6 harbor porpoise x 2.5 30-day periods).

[[Page 12224]]

    During all DTH activities, the Level A harassment zone is larger 
than the shutdown zone, but smaller than the Level B zone. As such it 
is possible that Dall's porpoise may enter the Level A harassment zone 
and stay long enough to incur AUD INJ before exiting. For DTH of 19-24-
in steel piles, the ratio of the Level A harassment area that exceeds 
the shutdown zone to the Level B harassment area is 0.14. This activity 
is predicted to take place on 6 construction days (6 construction days 
/ 30 days = 0.2 30-day construction periods). For DTH of 24-42-in steel 
piles, the ratio of the Level A harassment area that exceeds the 
shutdown zone to the Level B harassment area is 0.50. This activity is 
predicted to take place on 18 construction days (18 construction days / 
30 days = 0.6 30-day construction periods). As such, two takes by Level 
A harassment are proposed for authorization [(0.14 x 1 group x 6 harbor 
porpoise x 0.2 30-day construction periods) + (0.5 x 1 group x 6 harbor 
porpoise x 0.6 30-day construction periods) = 2.0 takes by Level A 
harassment].
    During all impact pile driving, the Level A harassment zone is 
larger than the Level B harassment zone. These activities are predicted 
to take place on 17 construction days (17 construction days / 30 days = 
0.6 30-day construction periods). Estimated take by Level A harassment 
for these activities result in four based on 1 group x 6 harbor 
porpoise x 0.6 30 day construction periods (1 x 6 x 0.6 = 3.6 takes by 
Level A harassment).
    Takes by Level B harassment were modified to deduct the proposed 
amount of take by Level A harassment estimated in cases where the Level 
A zone is smaller than the Level B harassment zone (i.e., 16 total 
exposures-2 takes by Level A harassment estimated during DTH activities 
= 14 takes by Level B harassment). Therefore, for harbor porpoise, NMFS 
proposes to authorize 6 takes by Level A harassment (2 takes + 4 takes) 
and 14 takes by Level B harassment, for a total of 20 takes in year 2.
Northern Fur Seal
    It is possible, though rare, that a northern fur seal could occur 
within the project area. Therefore, NMFS predicts that one northern fur 
seal could occur within the Level B harassment zone every 1 
construction month (30 days) each year, to account for the small but 
unlikely possibility that this species could occur within the project 
area. In year 1, the duration of the construction for which the Level B 
zone is larger than the Level A zone is 264 days (8.8 is the basic 30 
day period that corresponds to 1 construction months). This results in 
nine takes by Level B harassment of northern fur seal (1 northern fur 
seal x 8.8 30-day periods). Because exposure estimates are low, and the 
Level A harassment zones are larger than are likely observable during 
impact pile driving and DTH of 24-42-inch steel piles, NMFS proposed to 
authorize these nine takes by either Level A harassment or Level B 
harassment.
    In year 2, the duration of the construction for which the Level B 
harassment zone is larger than the Level A harassment zone is 76 days 
(2.5 is the basic 30 day period that corresponds to 1 construction 
months). This results in three takes by Level B harassment of northern 
fur seal (1 northern fur seal x 2.5 30-day periods). Because exposure 
estimates are low, and the Level A harassment zones are larger than are 
likely observable during impact pile driving and DTH of 24-42-inch 
steel piles, NMFS proposed to authorize these three takes by either 
Level A harassment or Level B harassment.
Steller Sea Lion
    While data are limited, the Sunaq Tribe of Kodiak suggests that the 
bottom topography of Womens Bay is not conducive to Steller sea lion 
foraging, but it is possible that Steller sea lions will occur 
intermittently in Womens Bay (Van Daele, 2024, personal communication). 
Therefore, NMFS predicts that one group of two Steller sea lions could 
occur within the Level B harassment zone every 2 construction weeks (14 
days) each year.
    In year 1, the duration of the construction for which the Level B 
harassment zone is larger than the Level A harassment zone is 264 days 
(18.9 is the basic 14 day period that corresponds to 2 construction 
weeks). This results in 38 takes by Level B harassment of Steller sea 
lion (2 Steller sea lion x 18.9 14-day periods).
    During DTH of 25-42-inch steel piles and all impact pile driving 
activities except for 24-inch pre-cast concrete, the Level A harassment 
zone is larger than the shutdown zone, but smaller than the Level B 
harassment zone. As such it is possible that Steller sea lions may 
enter the Level A harassment zone and stay long enough to incur AUD INJ 
before exiting. For DTH of 25-42-in steel piles, the ratio of the Level 
A harassment area that exceeds the shutdown zone to the Level B 
harassment area is 0.07. This activity is predicted to take place on 48 
construction days (48 construction days / 14 days = 3.4 14-day 
construction periods). For impact installation of 42-in steel, the 
ratio of the Level A harassment area that exceeds the shutdown zone to 
the Level B harassment area is 0.12. This activity is predicted to take 
place on 32 construction days (32 construction days / 14 days = 2.3 14-
day construction periods). For impact installation of 24-in steel, the 
ratio of the Level A harassment area that exceeds the shutdown zone to 
the Level B harassment area is also 0.08. This activity is predicted to 
take place on 5 construction days (5 construction days / 14 days = 0.4 
14-day construction periods).
    As such, two takes by Level A harassment is proposed for 
authorization [(0.07 x 1 group x 2 Steller sea lion x 3.4 14-day 
construction periods) + (0.12 x 1 group x 2 Steller sea lion x 2.3 14-
day construction periods) + 0.08 x 1 group x 2 Steller sea lion x 0.4 
14-day construction periods = 1.08 takes by Level A harassment].
    Takes by Level B harassment were modified to deduct the proposed 
amount of take by Level A harassment estimated in cases where the Level 
A zone is smaller than the Level B zone (i.e., 38 total exposures-2 
takes by Level A harassment activities = 36 takes by Level B 
harassment). Therefore, for Steller sea lion, NMFS proposes to 
authorize 2 takes by Level A harassment and 36 takes by Level B 
harassment, for a total of 38 takes in year 1.
    In year 2, the duration of the construction for which the Level B 
harassment zone is larger than the Level A harassment zone is 76 days 
(5.4 is the basic 14 day period that corresponds to 2 construction 
weeks). This results in 11 takes by Level B harassment of Steller sea 
lion (2 Steller sea lion x 5.4 14-day periods).
    During DTH of 25-42-inch steel piles and all impact pile driving 
activities except for 24-inch pre-cast concrete, the Level A harassment 
zone is larger than the shutdown zone, but smaller than the Level B 
harassment zone. As such it is possible that Steller sea lion may enter 
the Level A harassment zone and stay long enough to incur AUD INJ 
before exiting. For DTH of 25-42-in steel piles, the ratio of the Level 
A harassment area that exceeds the shutdown zone to the Level B 
harassment area is 0.07. This activity is predicted to take place on 18 
construction days (18 construction days / 14 days = 1.3 14-day 
construction periods). For impact installation of 42-in steel, the 
ratio of the Level A harassment area that exceeds the shutdown zone to 
the Level B harassment area is 0.12. This activity is predicted to take 
place on 5

[[Page 12225]]

construction days (5 construction days / 14 days = 0.4 14-day 
construction periods). For impact installation of 36-in steel, the 
ratio of the Level A harassment area that exceeds the shutdown zone to 
the Level B harassment area is 0.14. This activity is predicted to take 
place on 3 construction days (3 construction days / 14 days = 0.2 14-
day construction periods). For impact installation of 30-in steel, the 
ratio of the Level A harassment area that exceeds the shutdown zone to 
the Level B harassment area is 0.08. This activity is predicted to take 
place on 5 construction days (5 construction days / 14 days = 0.4 14-
day construction periods). For impact installation of 24-in steel, the 
ratio of the Level A harassment area that exceeds the shutdown zone to 
the Level B harassment area is also 0.08. This activity is predicted to 
take place on 4 construction days (4 construction days / 14 days = 0.3 
14-day construction periods).
    As such, one take by Level A harassment is proposed for 
authorization [(0.07 x 1 group x 2 Steller sea lion x 1.3 14-day 
construction periods) + (0.12 x 1 group x 2 Steller sea lion x 0.4 14-
day construction periods) + 0.14 x 1 group x 2 Steller sea lion x 0.2 
14-day construction periods + (0.08 x 1 group x 2 Steller sea lion x 
0.4 14-day construction periods) + (0.08 x 1 group x 2 Steller sea lion 
x 0.3 14-day construction periods) = 0.43 takes by Level A harassment].
    Takes by Level B harassment were modified to deduct the proposed 
amount of take by Level A harassment estimated in cases where the Level 
A harassment zone is smaller than the Level B harassment zone (i.e., 11 
total exposures-1 take by Level A harassment activities = 10 takes by 
Level B harassment). Therefore, for Steller sea lion, NMFS proposes to 
authorize 1 take by Level A harassment and 10 takes by Level B 
harassment, for a total of 11 takes in year 2.
Harbor Seal
    Harbor seals are known to frequent nearshore habitats and have been 
documented in large numbers in the project area. Based on local data, 
NMFS predicts that one group of 24 harbor seal are could occur within 
the Level B harassment zone every 1 construction week (7 days) each 
year.
    In year 1, the duration of the construction for which the Level B 
harassment zone is larger than the Level A harassment zone is 257 days 
(36.7 is the basic 7 day period that corresponds to 1 construction 
week). This results in 882 takes by Level B harassment of harbor seal 
(24 harbor seal x 36.7 7-day periods).
    During all DTH activities, the Level A harassment zone is larger 
than the shutdown zone, but smaller than the Level B harassment zone. 
As such it is possible that harbor porpoise may enter the Level A 
harassment zone and stay long enough to incur AUD INJ before exiting. 
For DTH of 19-24-in steel piles, the ratio of the Level A harassment 
area that exceeds the shutdown zone to the Level B harassment area is 
0.09. This activity is predicted to take place on 7 construction days 
(7 construction days / 7 days = 1 7-day construction periods). For DTH 
of 24-42-in steel piles, the ratio of the Level A harassment area that 
exceeds the shutdown zone to the Level B harassment area is 0.19. This 
activity is predicted to take place on 48 construction days (48 
construction days / 7 days = 6.9 7-day construction periods). As such, 
34 takes by Level A harassment are proposed for authorization [(0.09 x 
1 group x 24 harbor seal x 1 7-day construction periods) + (0.19 x 1 
group x 24 harbor seal x 6.9 7-day construction periods) = 34 takes by 
Level A harassment].
    During all impact pile driving, the Level A harassment zone is 
larger than the Level B harassment zone. These activities are predicted 
to take place on 44 construction days (44 construction days / 7 days = 
6.3 1-week construction periods). Estimated take by Level A harassment 
for these activities result in 151 based on 1 group x 24 harbor seal x 
6.3 14 day construction periods (1 x 24 x 6.3 = 151.2 takes by Level A 
harassment).
    Takes by Level B harassment were modified to deduct the proposed 
amount of take by Level A harassment estimated in cases where the Level 
A harassment zone is smaller than the Level B harassment zone (i.e., 
882 total exposures-34 takes by Level A harassment estimated during DTH 
activities = 848 takes by Level B harassment). Therefore, for harbor 
seal, NMFS proposes to authorize 185 takes by Level A harassment (34 
takes + 151 takes) and 848 takes by Level B harassment, for a total of 
1,033 takes in year 1.
    In year 2, the duration of the construction for which the Level B 
harassment zone is larger than the Level A harassment zone is 76 days 
(10.9 is the basic 7 day period that corresponds to 1 construction 
week). This results in 262 takes by Level B harassment of harbor seal 
(24 harbor seal x 10.9 7-day periods).
    During all DTH activities, the Level A harassment zone is larger 
than the shutdown zone, but smaller than the Level B harassment zone. 
As such it is possible that harbor seal may enter the Level A 
harassment zone and stay long enough to incur AUD INJ before exiting. 
For DTH of 19-24-in steel piles, the ratio of the Level A harassment 
area that exceeds the shutdown zone to the Level B harassment area is 
0.09. This activity is predicted to take place on 6 construction days 
(6 construction days / 7 days = 0.86 7-day construction periods). For 
DTH of 24-42-in steel piles, the ratio of the Level A harassment area 
that exceeds the shutdown zone to the Level B harassment area is 0.19. 
This activity is predicted to take place on 18 construction days (18 
construction days / 7 days = 2.6 7-day construction periods). As such, 
14 takes by Level A harassment are proposed for authorization [(0.09 x 
1 group x 24 harbor seal x 0.86 7-day construction periods) + (0.19 x 1 
group x 14 harbor seal x 2.6 7-day construction periods) = 13.57 takes 
by Level A harassment].
    During all impact pile driving, the Level A harassment zone is 
larger than the Level B harassment zone. These activities are predicted 
to take place on 17 construction days (17 construction days / 7 days = 
2.4 7-day construction periods). Estimated take by Level A harassment 
for these activities result in 58 based on 1 group x 24 harbor seal x 
2.4 7-day construction periods (1 x 24 x 2.4 = 57.6 takes by Level A 
harassment).
    Takes by Level B harassment were modified to deduct the proposed 
amount of take by Level A harassment estimated in cases where the Level 
A zone is smaller than the Level B zone (i.e., 262 total exposures-14 
takes by Level A harassment estimated during DTH activities = 248 takes 
by Level B harassment). Therefore, for harbor seal, NMFS proposes to 
authorize 72 takes by Level A harassment (14 takes + 58 takes) and 248 
takes by Level B harassment, for a total of 320 takes in year 2.
Northern Elephant Seal
    Although rare, Northern elephant seals could occur in the project 
area (Van Daele, 2024, personal communication). NMFS predicts that one 
northern elephant seal could occur within the Level B harassment zone 
every 2 construction weeks (14 days), each year. In year 1, the 
duration of the construction for which the Level B harassment zone is 
larger than the Level A harassment zone is 257 days (18.4 is the basic 
14 day period that corresponds to 2 construction weeks). This results 
in 19 takes by Level B harassment of northern fur seal (1 northern 
elephant

[[Page 12226]]

seal x 18.4 14-day periods). Because exposure estimates are low, and 
the Level A harassment zones are larger than are likely observable 
during impact pile driving and DTH, NMFS proposed to authorize these 19 
takes by either Level A harassment or Level B harassment.
    In year 2, the duration of the construction for which the Level B 
harassment zone is larger than the Level A harassment zone is 76 days 
(5.4 is the basic 14 day period that corresponds to 2 construction 
weeks). This results in six takes by Level B harassment of northern 
elephant seal (1 northern elephant seal x 5.4 14-day periods). Because 
exposure estimates are low, and the Level A harassment zones are larger 
than are likely observable during impact pile driving and DTH, NMFS 
proposed to authorize these six takes by either Level A harassment or 
Level B harassment.

                                   Table 10--Take by Stock and Harassment Type and as a Percentage of Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        Proposed take--year 1     Proposed take--year 2       Take as
                                                                                     ----------------------------------------------------  percentage of
                                                                                                                                               stock
                     Species                                     Stock                  Level A      Level B      Level A      Level B      abundance--
                                                                                       harassment   harassment   harassment   harassment   year 1, (year
                                                                                                                                                2)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gray Whale......................................  Eastern N Pacific.................            0            3            0            3            (<1)
Fin Whale.......................................  Northeast Pacific.................            0            6            0            6          *, (*)
Humpback Whale..................................  Hawai[revaps]i....................            0            2            0            2        <1, (<1)
                                                  Mexico-N Pacific..................                                                              *, (*)
                                                  Western N Pacific.................                                                            <1, (<1)
Minke Whale.....................................  Alaska............................            0            2            0            2          *, (*)
Killer Whale....................................  Eastern North Pacific-Alaska                  0           62            0           18        <1, (<1)
                                                   Resident.
                                                  Eastern North Pacific-Gulf of                                                                  11, (3)
                                                   Alaska, Aleutian Islands, and
                                                   Bering Sea.
Pacific White-sided Dolphin.....................  North Pacific.....................            0           10            0           10        <1, (<1)
Dall's Porpoise.................................  Alaska............................           10           31            5            8          *, (*)
Harbor Porpoise.................................  Gulf of Alaska....................           14           47            6           20        <1, (<1)
                                                                                     ----------------------------------------------------
Northern Fur Seal...............................  Eastern Pacific...................              9
                                                                         3                            <1, (<1)
                                                                                     ----------------------------------------------------
Steller Sea Lion................................  Western...........................            2           36            1           10        <1, (<1)
Harbor Seal.....................................  South Kodiak......................          185          848           72          248      3.9, (1.2)
                                                                                     ----------------------------------------------------
Northern Elephant Seal..........................  CA Breeding.......................             19
                                                                         6                            <1, (<1)
--------------------------------------------------------------------------------------------------------------------------------------------------------
* A reliable abundance estimate is not available for this stock.

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.
    Shutdown Zones--For all pile driving and DTH activities, USCG 
proposes to implement shutdowns within designated zones. 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 
vary based on the activity type and marine mammal hearing group (table 
11 and 12). In most cases, the shutdown zones are based on the 
estimated Level A harassment isopleth distances for each hearing group. 
However, in cases where it would be challenging to detect marine 
mammals at the Level A harassment isopleth (e.g., for very high-
frequency cetaceans, phocids, and otariids during most impact pile 
driving), smaller shutdown zones have been proposed (table 11 and 12).
    Construction supervisors and crews, PSOs, and relevant USCG staff 
must avoid direct physical interaction with marine mammals during 
construction activity. If a marine mammal comes within 25 m of such 
activity, operations must cease and vessels must reduce speed to the 
minimum level required to maintain steerage and safe working 
conditions, as necessary to avoid direct physical interaction. If an 
activity is delayed or halted due to the presence of a marine mammal, 
the activity may not commence or resume until either the animal has 
voluntarily exited and been visually confirmed beyond the

[[Page 12227]]

shutdown zone indicated in table 11 and 12, or 30 minutes (ESA-listed 
large whales) or 15 minutes (all other species) have passed without re-
detection of the animal.
    Finally, construction activities must be halted upon observation of 
a species for which incidental take is not authorized or a species for 
which incidental take has been authorized but the authorized number of 
takes has been met entering or within any harassment zone. If a marine 
mammal species not covered under this IHA enters a harassment zone, all 
in-water activities will cease until the animal leaves the zone or has 
not been observed for at least 15 minutes. Pile driving will proceed if 
the unauthorized species is observed leaving the harassment zone or if 
15 minutes have passed since the last observation.

                                                      Table 11--Proposed Shutdown Zones (m): Year 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
              Pile driving method                           Pile type              Pile size      LF          HF          VHF         PW          OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation and Extraction.........  Timber..........................          14          25          25          25          25          25
                                                                                          24
                                                Steel...........................          12
                                                                                          14
                                                                                          24
                                                                                          36          60                      50          80          30
                                                                                          42          50                                  70          25
                                                Steel/Concrete..................          24          30                      25          40
                                                Precast Concrete................          24          25                                  30
                                                Vibroflot.......................          30          30                                  40
Impact Pile Driving...........................  Steel...........................          24       1,940         250         300         300         300
                                                                                          42       3,200         410
                                                Precast Concrete................          24         560          80                                 190
DTH...........................................  Steel...........................       19-24         800         110                                 300
                                                                                       24-42       1,720         220
--------------------------------------------------------------------------------------------------------------------------------------------------------


                                                      Table 12--Proposed Shutdown Zones (m): Year 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
              Pile driving method                           Pile type              Pile size      LF          HF          VHF         PW          OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation and Extraction.........  Steel...........................          24          25          25          25          25          25
                                                                                          30          25
                                                                                          36          60                      50          80          30
                                                                                          42          50                                  70          25
Impact Pile Driving...........................  Steel...........................          24       1,940         250         300         300         300
                                                                                          30
                                                                                          36       3,720         480
                                                                                          42       3,200         410
DTH...........................................  Steel...........................       19-24         800         110
                                                                                       24-42       1,720         220
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Protected Species Observers (PSOs)--The number and placement of 
PSOs during all construction activities (described in the Proposed 
Monitoring and Reporting section) would ensure that the entire shutdown 
zone is visible. USCG would employ at least one PSOs during all 
vibratory pile driving and removal activities and at least two PSOs 
during all impact pile driving and DTH activities.
    Monitoring for Level A and Level B Harassment--PSOs would monitor 
the shutdown zones and beyond to the extent that PSOs can see. 
Monitoring beyond the shutdown zones enables 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. If a marine 
mammal enters either harassment zone, PSOs will document the marine 
mammal's presence and behavior.
    Pre- and Post-Activity Monitoring--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 zones and as 
much as the harassment zones as possible for a period of 30 minutes. 
Pre-start clearance monitoring must be conducted during periods of 
visibility sufficient for the lead PSO to determine that the shutdown 
zones are clear of marine mammals. If the shutdown zone is obscured by 
fog or poor lighting conditions, in-water construction activity will 
not be initiated until the entire shutdown zone is visible. Pile 
driving may commence following 30 minutes of observation when the 
determination is made that the shutdown zones are clear of marine 
mammals. If a marine mammal is observed entering or within shutdown 
zones, pile driving activity 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 
or 30 minutes (ESA-listed large whales) or 15 minutes have passed 
without re-detection of the animal. If a marine mammal for which take 
by Level B harassment is authorized is present in the Level B 
harassment zone, activities may begin.
    Soft-Start--The use of soft-start procedures are believed to 
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. For impact pile driving, contractors 
would be required to provide an initial set of three strikes from the 
hammer at reduced energy, with each strike followed by a

[[Page 12228]]

30-second waiting period. This procedure would be conducted a total of 
three times before impact pile driving begins. 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. Soft start is not required during vibratory pile 
driving activities.
    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, and on the availability of such species or stock for 
subsistence uses.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present while 
conducting the activities. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     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 during pile driving activities must be 
conducted by NMFS-approved PSOs 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 must 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 experience performing the duties of a PSO during construction 
activities pursuant to NMFS-issued take authorization;
     Where a team of three or more PSOs is required, a lead 
observer or monitoring coordinator will be designated. The lead 
observer will be required to have prior experience working as a marine 
mammal observer during construction activity pursuant to a NMFS-issued 
incidental take authorization; and,
     PSOs must be approved by NMFS prior to beginning any 
activity subject to this IHA.
    PSOs should also have the following qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including 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.
    Visual monitoring would be conducted by trained PSOs positioned at 
suitable vantage points, such as the project site, and the southern tip 
of Nyman Peninsula. During vibratory pile driving and removal, at least 
one PSO would placed near the pile driving site and have an 
unobstructed view of all water within the shutdown zone. During impact 
pile driving and DTH, a second PSO would be placed at a location like 
the southern end of Nyman Peninsula ensure the larger shutdown zones 
would be observable as well.
    Monitoring would be conducted 30 minutes before, during, and 30 
minutes after all in water construction activities. In addition, PSOs 
will record all incidents of marine mammal occurrence, regardless of 
distance from activity, and will 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

    USCG would submit a draft marine mammal monitoring report to NMFS 
within 90 days after the completion of pile driving activities, or 60 
days prior to a requested date of issuance of any future IHAs for the 
project, or other projects at the same location, whichever comes first. 
The marine mammal monitoring report will include an overall description 
of work completed, a narrative regarding marine mammal sightings, and 
associated PSO data sheets. Specifically, the report will include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including: (1) the number and type of piles that 
were driven and the method (e.g., impact or vibratory); and (2) total 
duration of driving time for each pile (vibratory driving) and 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 other relevant weather 
conditions including

[[Page 12229]]

cloud cover, fog, sun glare, and overall visibility to the horizon, and 
estimated observable distance;
     Upon observation of a marine mammal, the following 
information: (1) name of PSO who sighted the animal(s) and PSO location 
and activity at time of sighting; (2) time of sighting; (3) 
identification of the animal(s) (e.g., genus/species, lowest possible 
taxonomic level, or unidentified), PSO confidence in identification, 
and the composition of the group if there is a mix of species; (4) 
distance and location of each observed marine mammal relative to the 
pile being driven for each sighting; (5) estimated number of animals 
(min/max/best estimate); (6) estimated number of animals by cohort 
(adults, juveniles, neonates, group composition, etc.); (7) animal's 
closest point of approach and estimated time spent within the 
harassment zone; (8) description of any marine mammal behavioral 
observations (e.g., observed behaviors such as feeding or traveling), 
including an assessment of behavioral responses thought to have 
resulted from the activity (e.g., no response or changes in behavioral 
state such as ceasing feeding, changing direction, flushing, or 
breaching);
     Number of marine mammals detected within the harassment 
zones, by species; and,
     Detailed information about implementation of any 
mitigation (e.g., shutdowns and delays), a description of specific 
actions that ensued, and resulting changes in behavior of the 
animal(s), if any.
    A final report must be prepared and submitted within 30 calendar 
days following receipt of any NMFS comments on the draft report. If no 
comments are received from NMFS within 30 calendar days of receipt of 
the draft report, the report shall be considered final. All PSO data 
would be submitted electronically in a format that can be queried such 
as a spreadsheet or database and would be submitted with the draft 
marine mammal report.
    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the Holder must report the 
incident to the OPR, NMFS ([email protected] and 
[email protected]) and Alaska Regional Stranding network (877-925-
7773) as soon as feasible. If the death or injury was clearly caused by 
the specified activity, the Holder must immediately cease the 
activities until NMFS OPR 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 this IHA. The 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 animals(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 majority of our analysis applies to all 
the species listed in table 3, given that many of the anticipated 
effects of this project on different marine mammal stocks are expected 
to be relatively similar in nature. Where there are meaningful 
differences between species or stocks, or groups of species, in 
anticipated individual responses to activities, impact of expected take 
on the population due to differences in population status, or impacts 
on habitat, they are described independently in the analysis below.
    Pile driving, removal, and DTH activities associated with the 
project, as outlined 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 and, for some 
species, Level A harassment from underwater sounds generated by pile 
driving and removal. Potential takes could occur if individuals are 
present in the ensonified zone when these activities are underway.
    No serious injury or mortality is expected in either year, even in 
the absence of required mitigation measures, given the nature of the 
activities. Further, no take by Level A harassment is anticipated for 
any low-frequency or high-frequency cetaceans, due to the rarity of the 
species near the project area and the application of proposed 
mitigation measures, such as shutdown zones that encompass the Level A 
harassment zones for these species (see Proposed Mitigation section).
    In both Year 1 and Year 2, take by Level A harassment is proposed 
for authorization for six species (Dall's porpoise, harbor porpoise, 
northern fur seal, Steller sea lion, harbor seal, and northern elephant 
seal). Any take by Level A harassment is expected to arise from, at 
most, a small degree of AUD INJ (i.e., minor degradation of hearing 
capabilities within regions of hearing that align most completely with 
the energy produced by impact pile driving such as the low-frequency 
region below 2 kHz), not severe hearing impairment or impairment within 
the ranges of greatest hearing sensitivity. Animals would need to be 
exposed to higher levels and/or longer duration than are expected to 
occur here in order to incur any more than a small degree of PTS.
    Further, in both year 1 and year 2, the amount of take by Level A 
harassment proposed for authorization is very low. For six species, 
NMFS anticipates no take by Level A harassment over the duration of 
USCG's planned activities (both years); In year 1, NMFS expects no more 
than 6 takes by Level A harassment for Dall's porpoise in year 1 and 5 
in year 2; 15 takes by Level A harassment for harbor porpoise in year 1 
and 5 in year 2; 19 takes by Level A

[[Page 12230]]

harassment for northern elephant seal in year 1 and 6 in year 2; and 2 
takes by Level A harassment for Steller sea lion in year 1 and 1 in 
year 2. The proposed amount of take by Level A harassment for harbor 
seal is a bit larger--185 takes in year 1 and 73 in year 2. However, 
for all hearing groups, if hearing impairment occurs, it is most likely 
that the affected animal would lose only a few dB in its hearing 
sensitivity. Due to the small degree anticipated, any AUD INJ 
potentially incurred would not be expected to affect the reproductive 
success or survival of any individuals, much less result in adverse 
impacts on the species or stock.
    Additionally, some subset of the individuals that are behaviorally 
harassed could also simultaneously incur some small degree of TTS for a 
short duration of time. However, since the hearing sensitivity of 
individuals that incur TTS is expected to recover completely within 
minutes to hours, it is unlikely that the brief hearing impairment 
would affect the individual's long-term ability to forage and 
communicate with conspecifics, and would therefore not likely impact 
reproduction or survival of any individual marine mammal, let alone 
adversely affect rates of recruitment or survival of the species or 
stock.
    Effects on individuals that are taken by Level B harassment in the 
form of behavioral disruption, on the basis of reports in the 
literature as well as monitoring from other similar activities, would 
likely be limited to reactions such as avoidance, increased swimming 
speeds, increased surfacing time, or decreased foraging (if such 
activity were occurring) (e.g., Thorson and Reyff, 2006). Most likely, 
individuals would simply move away from the sound source and 
temporarily avoid the area where pile driving is occurring. If sound 
produced by project activities is sufficiently disturbing, animals are 
likely to simply avoid the area while the activities are occurring. We 
expect that any avoidance of the project areas by marine mammals would 
be temporary in nature and that any marine mammals that avoid the 
project areas during construction would not be permanently displaced. 
Short-term avoidance of the project areas and energetic impacts of 
interrupted foraging or other important behaviors is unlikely to affect 
the reproduction or survival of individual marine mammals, and the 
effects of behavioral disturbance on individuals is not likely to 
accrue in a manner that would affect the rates of recruitment or 
survival of any affected stock.
    The project is also not expected to have significant adverse 
effects on affected marine mammals' habitats. The project activities 
would not modify existing marine mammal habitat for a significant 
amount of time. The activities may cause a low level of turbidity in 
the water column and some fish may leave the area of disturbance, thus 
temporarily impacting marine mammals' foraging opportunities in a 
limited portion of the foraging range; but, because of the short 
duration of the activities and the relatively small area of the habitat 
that may be affected (with no known particular importance to marine 
mammals), the impacts to marine mammal habitat are not expected to 
cause significant or long-term negative consequences.
    Steller sea lions are not common in the project area, and there are 
no essential primary constituent elements (biological or physical 
features within designated critical habitat that are essential to the 
conservation of the listed species), such as haulouts or rookeries, 
present. The nearest haulout is 4 km away on a man-made float. 
Therefore, the project is not expected to have significant adverse 
effects on the critical habitat of Western DPS Steller sea lions.
    While waters off Kodiak have been identified as BIAs for gray 
whale, fin whale, and humpback whale, only a small portion of the 
project area at the mouth of Womens Bay overlaps with a minimal part of 
these identified areas. The shallow waters of Womens Bay do not 
represent habitat for these species and occurrence of these species is 
low in the project area.
    In addition, it is unlikely that minor noise effects in a small, 
localized area of habitat would have any effect on the reproduction or 
survival of any individuals, much less these stocks' annual rates of 
recruitment or survival. In combination, we believe that these factors, 
as well as the available body of evidence from other similar 
activities, demonstrate that the potential effects of the specified 
activities would have only minor, short-term effects on individuals. 
The specified activities are not expected to impact rates of 
recruitment or survival and would therefore not result in population-
level impacts.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect any of the species 
or stocks through effects on annual rates of recruitment or survival:
     No serious injury or mortality is anticipated or proposed 
for authorization;
     No take by Level A harassment is proposed for 6 out of 12 
species;
     Take by Level A harassment would be very small amounts for 
most species and of a low severity;
     For all species, Womens Bay is a very small and peripheral 
part of their range;
     Proposed takes by Level B harassment are relatively low 
for most stocks. Level B harassment would be primarily in the form of 
behavioral disturbance, resulting in avoidance of the project areas 
around where impact or vibratory pile driving 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 on 
their populations;
     The ensonified areas are very small relative to the 
overall habitat ranges of all species and stocks, and overlap with 
known areas of important habitat is minimal; and,
     The lack of anticipated significant or long-term negative 
effects to marine mammal habitat.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted previously, only take of small numbers of marine mammals 
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is fewer than one-third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    The instances of take NMFS proposed to authorize is below one third 
of the estimated stock abundance for all species. The number of animals 
authorized to be taken from these stocks would be considered small 
relative to the relevant stocks' abundances even if

[[Page 12231]]

each estimated taking occurred to a new individual. 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 official abundance estimates available for humpback 
whale (Mexico-North Pacific stock), fin whale (Northeast Pacific 
stock), minke whale (Alaska stock), and Dall's porpoises (Alaska 
stock).
    The most recent abundance estimate for the Mexico-North Pacific 
stock of humpback whale is likely unreliable as it is more than 8 years 
old. There are 2 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 2 takes by Level B 
harassment proposed for authorization each year is small relative to 
the estimated abundance (<1 percent), even if each proposed take 
occurred to a new individual. Young et al. (2024) estimate the minimum 
stock size for the Northeast Pacific stock of fin whale for the areas 
surveyed is 2,554 individuals. Therefore, the six takes by Level B 
harassment of this stock each year 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 (Young et al., 2024). Therefore, the 2 takes by Level 
B harassment each year 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 41 takes 
proposed for authorization in year 1, and the 13 takes proposed for 
authorization in year 2, 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.
    The USCG indicated that most recent data from Kodiak Station, which 
is the closest community observation station for subsistence 
harvesting, is from 1991 and does not show any marine mammal harvest 
data. The most recent data from the Old Harbor Station, which is 
located southeast of Kodiak Station is from 2018 and indicates that 37 
marine mammals were harvested that year (harbor seals, steller sea 
lion, unidentified marine mammal). The USCG sent scoping letters to 
potentially affected entities (local governments, Alaska native 
organizations). No concerns related to potential impacts on marine 
mammal subsistence activities and resources were provided.
     As noted above, recent data suggests that subsistence 
harvest of marine mammals does not currently occur in the project area. 
Further, construction activities would be temporary and localized to 
Womens Bay, near an active USCG base where human presence is common, 
marine mammal occurrence is low, and local marine mammals are likely 
accustomed to human activities. Further, mitigation measures will be 
implemented to minimize disturbance of marine mammals in the project 
area;
    Based on the description of the specified activity, the measures 
described to minimize adverse effects on the availability of marine 
mammals for subsistence purposes, and the proposed mitigation and 
monitoring measures, NMFS has preliminarily determined that there will 
not be an unmitigable adverse impact on subsistence uses from 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 ESA Alaska Regional Office 
(AKRO).
    NMFS is proposing to authorize take of humpback whale (Mexico-North 
Pacific and Western North Pacific), fin whale (northeast Pacific), and 
Steller sea lion (Western DPS), which are listed under the ESA. The 
Permits and Conservation Division has requested initiation of section 7 
consultation with the AKRO for the issuance of this IHA. NMFS will 
conclude the ESA consultation prior to reaching a determination 
regarding the proposed issuance of the authorization.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue two consecutive IHAs to USCG for conducting Base Kodiak Vessel 
Homeporting Facility Project in Womens Bay, Kodiak, Alaska between May 
19, 2025 and May 18, 2026 and May 19, 2026 and May 18, 2027, 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 authorization, 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 this IHA or a subsequent 
renewal IHA.
    On a case-by-case basis, NMFS may issue a one-time, 1-year renewal 
IHA following notice to the public providing an additional 15 days for 
public comments when (1) up to another year of identical or nearly 
identical activities as described in the Description of Proposed 
Activity section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activity section of this 
notice would not be completed by the time the IHA expires and a renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed renewal IHA effective date (recognizing

[[Page 12232]]

that the renewal IHA expiration date cannot extend beyond 1 year from 
expiration of the initial IHA).
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take).
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
     Upon review of the request for renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: March 7, 2025.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2025-03967 Filed 3-13-25; 8:45 am]
BILLING CODE 3510-22-P