[Federal Register Volume 88, Number 209 (Tuesday, October 31, 2023)]
[Notices]
[Pages 74451-74478]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-23970]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XD325]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Eareckson Air Station Fuel Pier 
Repair in Alcan Harbor on Shemya Island, Alaska

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; proposed incidental harassment authorization; request 
for comments on proposed authorization and possible renewal.

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SUMMARY: NMFS has received a request from the U.S Army Corps of 
Engineers (USACE) on behalf of the Pacific Air Forces Regional Support 
Center (USAF) for authorization to take marine mammals incidental to 
the Eareckson Air Station (EAS) Fuel Pier Repair in Alcan Harbor, 
Shemya Island, Alaska. Pursuant to the Marine Mammal Protection Act 
(MMPA), NMFS is requesting comments on its proposal to issue an 
incidental harassment authorization (IHA) to incidentally take marine 
mammals during the specified activities. NMFS is also requesting 
comments on a possible one-time, 1-year renewal that could be issued 
under certain circumstances and if all requirements are met, as 
described in the Request for Public Comments section at the end of this 
notice. NMFS will consider public comments prior to making any final 
decision on the issuance of the requested MMPA authorization and agency 
responses will be summarized in the final notice of our decision.

DATES: Comments and information must be received no later than November 
30, 2023.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service and should be submitted via email to 
<a href="/cdn-cgi/l/email-protection#6d24393d432b01080004030a2d03020c0c430a021b"><span class="__cf_email__" data-cfemail="337a67631d755f565e5a5d54735d5c52521d545c45">[email protected]</span></a>. Electronic copies of the application and 
supporting documents, as well as a list of the references cited in this 
document, may be obtained online at: 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 mitigation, 
monitoring and reporting of the takings are set forth. The definitions 
of all applicable MMPA statutory terms cited above are included in the 
relevant sections below.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an IHA) 
with respect to potential impacts on the human environment. This action 
is consistent with categories of activities identified in Categorical 
Exclusion B4 (IHAs with no anticipated serious injury or mortality) of 
the Companion Manual for NAO 216-6A, which do not individually or 
cumulatively have the potential for significant impacts on the quality 
of the human environment and for which we have not identified any 
extraordinary circumstances that would preclude this categorical 
exclusion. Accordingly, NMFS has preliminarily determined that the 
issuance of the proposed IHA qualifies to be categorically excluded 
from further NEPA review.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA request.

Summary of Request

    On May 15, 2023, NMFS received a request from the USACE on behalf 
of USAF for an IHA to take marine mammals incidental to construction 
associated with the EAS Fuel Pier Repair in Alcan Harbor on Shemya 
Island, Alaska. Following NMFS' review of the application, and 
discussions between NMFS and USAF, the application was deemed adequate 
and complete on September 19, 2023. The USAF's request is for take of 
12 species of marine mammals, by Level B harassment and, for a subset 
of these species, Level A harassment. Neither USAF nor NMFS expect 
serious injury or mortality to result from this activity and, 
therefore, an IHA is appropriate.

[[Page 74452]]

    This proposed IHA would cover 1 year of a larger 3-year project 
that involves construction activities that will not result in the take 
of marine mammals (i.e., movement, mobilization, and staging of 
equipment; replacing the pier deck; and installing an engineered 
revetment along the western shoreline).

Description of Proposed Activity

Overview

    The USAF is proposing to conduct long-term repairs on the only 
existing fuel pier at EAS on Shemya Island, Alaska. The fuel delivered 
to the pier is used by the island generator systems to aid in the 
operation of homeland defense early warning radar surveillance and 
communication systems. EAS also functions as an emergency divert 
airfield supporting commercial and air traffic destined for Japan, 
China, and other destinations in Asia and the Pacific. In February 
2020, a destructive storm left the fuel pier in critical condition. In 
2021, emergency repairs were completed to restore minimal function to 
the fuel pier. Long-term repairs are planned in order to prevent future 
degradation and catastrophic loss to the fuel pier, to maintain access 
to the pier, and to protect the shoreline facilities from further 
erosion. The activities that have the potential to take marine mammals, 
by Level A harassment and Level B harassment, include down-the-hole 
(DTH) drilling, vibratory and impact installation of temporary and 
permanent steel pipe piles, and vibratory removal of temporary steel 
pipe piles, and would introduce underwater sounds that may result in 
take, by Level A harassment and Level B harassment, of marine mammals. 
The marine construction associated with the proposed activities is 
planned to occur over 160 days over 1 year, accounting for weather 
delays and mechanical issues.

Dates and Duration

    The proposed IHA would be effective from April 1, 2024 to March 31, 
2025. The project would occur between April and October 2024 and would 
require approximately 160 days of pile driving. In-water construction 
activities would only occur during daylight hours, and typically over a 
12-hour work day, up to 7 days per week.

Specific Geographic Region

    The proposed activities would occur on the EAS Fuel Pier on Shemya 
Island, located in Section 16, Township 86 South, Range 257 West, of 
the Seward Meridian, Alaska. Shemya Island is a remote island in the 
western Aleutians. The fuel pier is located in Alcan Harbor, which 
opens to Shemya Pass to the west and the Bering Sea to its north and 
east. Alcan harbor is exposed to strong north winds. The dimensions of 
the new Pier footprint would be approximately 30 by 104 meters (m), or 
100 by 340 feet (ft). Depths at the project site range from 5 to 10 m 
(16 to 33 ft). However, the area of impact would extend 40 kilometers 
(km), or 25 miles (mi), into the southwest portion of the Bering Sea, 
reaching depths of approximately 3,900 m (2.4 mi).
    Shemya Island and its waters are within the Alaska Maritime 
National Wildlife Refuge, which if not for it being a military base, 
would typically be under the jurisdiction of U.S. Fish and Wildlife 
Service (USFWS, 2021). The fuel pier is the only pier on Shemya Island; 
there are no neighboring piers or docks. The next nearest developed 
location that is inhabited is Nikol'skoe, which is approximately 370 mi 
(595 km) west on Bering Island, Russia. Adak, Alaska, is approximately 
400 mi (644 km) to the east in the Central Aleutians. The United States 
Coast Guard previously maintained a long-range navigation station on 
Attu Island, Alaska, 28 mi (45 km) to the west, but that site has been 
abandoned for several years. All former Alaska Native village sites in 
the region have been abandoned since World War II.
BILLING CODE 3510-22-P

[[Page 74453]]

[GRAPHIC] [TIFF OMITTED] TN31OC23.000

[GRAPHIC] [TIFF OMITTED] TN31OC23.001

BILLING CODE 3510-22-C

Detailed Description of the Specified Activity

    The USAF is proposing to repair the fuel pier at EAS on Shemya 
Island, Alaska. As noted above, this proposed IHA would authorize take 
associated with Year 1 of a larger 3-year project. Please refer to 
USAF's application for

[[Page 74454]]

additional information about project components planned for the period 
beyond Year 1.
    The USAF estimates that Year 1 activities would include vessel 
movement and mobilization; pile installation for the fuel pier, 
screening and clearance for Munitions and Explosives of Concern (MEC) 
(see explanation below), remote equipment operations, removal of 
existing precast dolosse from the western shoreline, and crushing/
recycling concrete.
    The replacement fuel pier is within a Military Munitions Response 
Program (MMRP) site and although prior surveys and clearance of the 
Alcan Harbor Ordnance MMRP site have been completed, there is potential 
for munitions and explosives of concern to migrate within the site. As 
such, magnetometer-based surveys for MEC will be conducted prior to 
ground disturbing activities within the boundaries of the MMRP site to 
detect anomalies and inform follow-on actions to the extent 
practicable. Excavated material from in-water work will be further 
screened and cleared to remove any potential MEC. The material would be 
excavated with a clamshell bucket and placed in a hopper that deposits 
the material onto a conveyor leading to a 6-inch remote controlled 
grizzly rock screener. Subsequently, material six inches or larger 
would be inspected by UXO technicians for MEC prior to transfer by 
armored equipment to a screening plant with a specialized magnet belt 
to remove all potential metals and munitions. Cleared material would be 
transferred to an upland, low-grade staging area while MEC would be 
transferred from the construction site to the MEC storage and disposal 
site.
    Additionally, USAF anticipates approximately five vessels (i.e., 
tugboats towing barges) per season would be used for project 
activities, transiting between Seattle, WA and Shemya Island, AK, with 
some trips making a stop in Seward, Kodiak, or Anchorage, AK. With the 
exception of pile driving, these activities are not anticipated to 
result in take.
    The proposed fuel pier replacement project would include the 
installation of an interlocking steel pipe combi-wall system, which 
will require the installation and removal of 60 30-inch (in) temporary 
steel pipe piles and the installation of 208 42-inch round steel 
interlocking pipe piles using vibratory, impact, and/or DTH methods 
(table 1). USAF does not plan to operate multiple hammers concurrently.
    The interlocking steel pipe combi-wall system would be installed 15 
ft (4.6 m) off the existing fuel pier to encapsulate most of the 
existing structure. The steel combi-wall system would extend 
approximately 560 ft (171 m) from the northern bulkhead corner, along 
the entire Pier berthing face, and around the northern perimeter.
    Template frames for the pile wall would be installed to construct 
the new pier exterior structure and subsequently removed; template 
frames would be constructed to cantilever off the existing fuel pier 
structure (i.e., not be placed in the water). However, up to 60 30-inch 
(76-cm) template piles may be installed in the water to provide 
additional support. A remotely operated vibratory pile driving hammer 
would be used to drive the piles through the bottom sediment to 
specified depths. It is anticipated that a diesel or hydraulic impact 
hammer would be utilized to achieve the specified embedment depth of 44 
temporary piles. Up to six temporary piles in the southeast corner, 
where there is very little overburden, would likely need to be rock 
socketed into bedrock via a DTH.
    The main component of the combi-wall system would require the 
installation of 208 42-inch (107-cm) interlocking permanent steel pipe 
piles that would be installed using vibratory and impact pile driving 
to specified embedment depths. The pile interlocks would be designed to 
transfer soil and water pressure to the interlocking steel pipe piles, 
which would carry most of the load. In addition to vibratory and impact 
pile driving, it is expected that most, if not all permanent piling 
will require a rock socket into the bedrock, at a minimum of 30 ft (9 
m) below the mudline, using a DTH hammer and bit. The bit will be 
slightly larger than the outside diameter of the permanent pipe pile.
    Construction of the proposed dock would follow this sequence:
    1. Set one or two cantilevered templates utilizing existing fuel 
pier as support. These cantilevered templates would not be installed in 
the water. However, template piles may be installed in some areas to 
offer additional support (table 1).
    2. Within the frame, loft and stab 6-12 each 42-inch permanent 
pile.
    3. Within the frame, vibrate, impact, and DTH drill 42-inch 
diameter pipe pile. Only one pile would be driven at a time, even if 
two pile templates are used.
    4. Remove the frame and any temporary piles and move to the next 
permanent pile location.
    5. Repeat this process for placement of all the permanent piles.

                                                  Table 1--Summary of Piles To Be Installed and Removed
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                        Maximum     Maximum
                                                                            Vibratory     DTH pile     piles per   piles per     Maximum       Days of
                                                      Number of    Impact    duration  installation,     day--       day--      piles per   installation
              Installation or removal                   piles     strikers  per pile,   duration per    impact     vibratory    day--DTH       and/or
                                                                  per pile   minutes   pile, minutes     pile        pile         pile       removal \a\
                                                                                                        driving     driving   installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    42-inch Interlocking Steel Pipe Piles--Permanent
--------------------------------------------------------------------------------------------------------------------------------------------------------
Installation.......................................         208      1,800         30           180            4           4            3           122
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                                                           30-inch Steel Pipe Piles--Template
--------------------------------------------------------------------------------------------------------------------------------------------------------
Installation.......................................          60        900         15           150            4           4            3            17
Removal............................................                                                   ..........           4  ............  ............
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ USAF estimates a total of 160 construction days to account for weather delays and mechanical issues.

    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting sections).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, instead of reprinting the information. Additional 
information regarding population trends

[[Page 74455]]

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 2 lists all species or stocks for which take is expected and 
proposed to be authorized for this activity, and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and Endangered Species Act (ESA) and potential biological 
removal (PBR), where known. PBR is defined by the MMPA as the maximum 
number of animals, not including natural mortalities, that may be 
removed from a marine mammal stock while allowing that stock to reach 
or maintain its optimum sustainable population (as described in NMFS' 
SARs). While no serious injury or mortality is anticipated or proposed 
to be authorized here, PBR and annual serious injury and mortality from 
anthropogenic sources are included here as gross indicators of the 
status of the species or stocks and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Alaska 2022 SARs (Young et al., 2023). All values presented 
in table 2 are the most recent available at the time of publication and 
are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                              Table 2--Species Likely Impacted by the Specified Activities
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                                                                                                              Stock abundance (CV,
            Common name                  Scientific name              Stock             ESA/MMPA status;       Nmin, most recent       PBR     Annual M/
                                                                                       strategic (Y/N) \1\   abundance survey) \2\               SI \3\
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                                            Order Artiodactyla--Infraorder Cetacea--Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae
    Fin Whale......................  Balaenoptera physalus.  Northeast Pacific.....  E, D, Y                 UND (UND, UND, 2013)         UND        0.6
                                                                                                              \4\.
    Humpback Whale.................  Megaptera novaeangliae  Western North Pacific.  E, D, Y                 1,084, (0.088, 1,007,          3        2.8
                                                                                                              2006).
                                                             Mexico--North Pacific.  T, D, Y                 N/A (N/A, N/A, 2006)         UND       0.56
                                                                                                              \5\.
                                                             Hawai[revaps]i........  -, -, N                 11,278 (0.56, 7,265,         127       19.6
                                                                                                              2020).
    Minke Whale....................  Balaenoptera            Alaska................  -, -, -                 N/A (N/A, N/A, N/A)          UND          0
                                      acutorostrata.                                                          \6\.
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                                                  Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae
    Sperm whale....................  Physeter macrocephalus  North Pacific.........  E, D, Y                 UND (UND, UND, 2015)         UND        3.5
                                                                                                              \7\.
Family Ziphiidae (beaked whales)
    Baird's beaked whale...........  Berardius bairdii.....  Alaska................  -, -, N                 N/A (N/A, N/A, N/A)          N/A          0
                                                                                                              \8\.
    Stejneger's Beaked Whale.......  Mesoplodon stejnegeri.  Alaska................  -, -, N                 N/A (N/A, N/A, N/A)          N/A          0
                                                                                                              \8\.
Family Delphinidae
    Killer Whale...................  Orcinus orca..........  ENP Alaska Resident     -, -, N                 1,920 (N/A, 1,920,            19        1.3
                                                              Stock.                                          2019).
                                                             ENP Gulf of Alaska,     -, -, N                 587 (N/A, 587, 2012).        5.9        0.8
                                                              Aleutian Islands, and
                                                              Bering Sea.
Family Phocoenidae (porpoises)
    Dall's Porpoise................  Phocoenoides dalli....  Alaska................  -, -, N                 UND (UND, UND, 2015)         UND         37
                                                                                                              \9\.
Harbor Porpoise....................  Phocoena phocoena.....  Bering Sea............  -, -, Y                 UNK (UNK, N/A, 2008)         UND        0.4
                                                                                                              \10\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions)
    Northern Fur Seal..............  Callorhinus ursinus...  Eastern Pacific.......  -, D, Y                 626,618 (0.2,             11,403        373
                                                                                                              530,376, 2019).
    Steller Sea Lion...............  Eumetopias jubatus....  Western, U.S..........  E, D, Y                 52,932 (N/A, 52,932,         318        254
                                                                                                              2019).
Family Phocidae (earless seals)
    Harbor Seal....................  Phoca vitulina........  Aleutian Islands......  -, -, N                 5,588 (N/A, 5,366,            97         90
                                                                                                              2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: https://www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum
  estimate of stock abundance. In some cases, CV is not applicable (explain if this is the case).
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, vessel strike). 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.
\4\ 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 upon this estimate and the Nmin, the PBR value is likely negatively biased for the entire stock.
\5\ Abundance estimates are based upon data collected more than 8 years ago and therefore current estimates are considered unknown.
\6\ Reliable population estimates are not available for this stock. Please see Friday et al. (2013) and Zerbini et al. (2006) for additional information
  on numbers of minke whales in Alaska.
\7\ 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 negatively biased minimum
  abundance estimate.
\8\ Reliable abundance estimates for this stock are currently unavailable.
\9\ 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.

[[Page 74456]]

 
\10\ The best available abundance estimate and Nmin are 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. PBR for this stock is undetermined due to this estimate being older than 8 years.

    As indicated above, all 12 species (with 15 managed stocks) in 
table 2 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur. All species that could 
potentially occur in the proposed project area are included in table 3-
1 of the IHA application. While blue whale, gray whale, North Pacific 
right whale, Pacific white-sided dolphin, and ribbon seal could occur 
in the area, the temporal and/or spatial occurrence of these species is 
such that take is not expected to occur, and they are not discussed 
further beyond the explanation provided here. These species all have 
extremely low abundance and most are observed in areas outside of the 
project area.
    In addition, northern sea otter may be found the western Aleutians. 
However, this species is managed by the U.S. Fish and Wildlife Service 
and is not considered further in this document.

Fin Whale

    Fin whales are found in polar, temperate, and subtropical waters 
worldwide, where they inhabit deep, offshore waters and often travel in 
open seas away from coasts. Fin whales in the northeast Pacific are 
typically distributed off the coast of the Gulf of Alaska and the 
Bering and Chukchi Seas. In general, the spring and early summer are 
spent in cold, high latitude feeding waters as far north as Chukchi 
Sea, the Gulf of Alaska, Prince William Sound, along the Aleutian 
Islands, and west of Kodiak Island. In the fall, fin whales return to 
low latitudes for the winter breeding season, though they may remain in 
residence in their high latitude ranges if food resources remain 
plentiful.
    Although typically observed in groups of 6 to 10 individuals, fin 
whales are also sighted in pairs, alone, or in feeding aggregations up 
to 100 individuals. In the central eastern Bering Sea, most sightings 
have occurred along the continental shelf break in a zone of high prey 
abundance (Clark, 2008a). Across 119 days of three distinct marine 
mammal surveys completed from Shemya Island between 2016 and 2021, no 
fin whales were observed in the project area (see application). Note 
that Alcan harbor was included in island-wide monitoring of two of 
these surveys, and the third survey effort was conducted exclusively at 
the project site during an emergency repair of the fuel pier.

Humpback Whale

    On September 8, 2016, NMFS divided the once single population into 
14 distinct population segments (DPS) under the ESA, removed the 
species-level listing as endangered, and, in its place, listed four 
DPSs as endangered and one DPS as threatened (81 FR 62259, September 8, 
2016). The remaining nine DPSs were not listed. There are four DPSs in 
the North Pacific, including the Western North Pacific and Central 
America, which are listed as endangered, Mexico, which is listed as 
threatened, and Hawai[revaps]i, which is not listed.
    The 2022 Alaska and Pacific SARs described a revised stock 
structure for humpback whales which modifies the previous stocks 
designated under the MMPA to align more closely with the ESA-designated 
DPSs (Caretta et al., 2023; Young et al., 2023). Specifically, the 
three previous North Pacific humpback whale stocks (Central and Western 
North Pacific stocks and a CA/OR/WA stock) were replaced by five 
stocks, largely corresponding with the ESA-designated DPSs. These 
include the Western North Pacific and Hawai[revaps]i stocks and a 
Central America/Southern Mexico--CA/OR/WA stock (which corresponds with 
the Central America DPS). The remaining two stocks, corresponding with 
the Mexico DPS, are the Mainland Mexico--CA/OR/WA and Mexico--North 
Pacific stocks (Caretta et al., 2023; Young et al., 2023). The former 
stock is expected to occur along the west coast from California to 
southern British Columbia, while the latter stock may occur across the 
Pacific, from northern British Columbia through the Gulf of Alaska and 
Aleutian Islands/Bering Sea region to Russia.
    The Hawai[revaps]i stock consists of one demographically 
independent population (DIP)--Hawai[revaps]i--Southeast Alaska/Northern 
British Columbia DIP and one unit--Hawai[revaps]i--North Pacific unit, 
which may or may not be composed of multiple DIPs (Wade et al., 2021). 
The DIP and unit are managed as a single stock at this time, due to the 
lack of data available to separately assess them and lack of compelling 
conservation benefit to managing them separately (NMFS, 2023; NMFS, 
2019; NMFS, 2022b). The DIP is delineated based on two strong lines of 
evidence: genetics and movement data (Wade et al., 2021). Whales in the 
Hawai[revaps]i--Southeast Alaska/Northern British Columbia DIP winter 
off Hawai[revaps]i and largely summer in Southeast Alaska and Northern 
British Columbia (Wade et al., 2021). The group of whales that migrate 
from Russia, western Alaska (Bering Sea and Aleutian Islands), and 
central Alaska (Gulf of Alaska excluding Southeast Alaska) to 
Hawai[revaps]i have been delineated as the Hawai[revaps]i--North 
Pacific unit (Wade et al., 2021). There are a small number of whales 
that migrate between Hawai[revaps]i and southern British Columbia/
Washington, but current data and analyses do not provide a clear 
understanding of which unit these whales belong to (Wade et al., 2021; 
Caretta et al., 2023; Young et al., 2023).
    The Mexico--North Pacific unit is likely composed of multiple DIPs, 
based on movement data (Martien et al., 2021; Wade, 2021; Wade et al., 
2021). However, because currently available data and analyses are not 
sufficient to delineate or assess DIPs within the unit, it was 
designated as a single stock (NMFS, 2023a; NMFS, 2019; NMFS, 2022c). 
Whales in this stock winter off Mexico and the Revillagigedo 
Archipelago and summer primarily in Alaska waters (Martien et al., 
2021; Carretta et al., 2023; Young et al., 2023).
    The Western North Pacific stock consists of two units--the 
Philippines/Okinawa--North Pacific unit and the Marianas/Ogasawara--
North Pacific unit. The units are managed as a single stock at this 
time, due to a lack of data. Recognition of these units is based on 
movements and genetic data (Oleson et al., 2022). Whales in the 
Philippines/Okinawa--North Pacific unit winter near the Philippines and 
in the Ryukyu Archipelago and migrate to summer feeding areas primarily 
off the Russian mainland (Oleson et al., 2022). Whales that winter off 
the Mariana Archipelago, Ogasawara, and other areas not yet identified 
and then migrate to summer feeding areas off the Commander Islands, and 
to the Bering Sea and Aleutian Islands comprise the Marianas/
Ogasawara--North Pacific unit.
    Humpback whales that occur in the project area are predominantly 
members of the Hawai'i stock, which corresponds to the Hawai[revaps]i 
DPS (91 percent probability in the Aleutian Islands), and is not listed 
under the ESA. However, members of the Mexico North Pacific stock, 
which include the Mexico DPS and is listed as threatened, have a small 
potential to occur in the project location (7 percent probability in 
the Aleutians), and the Western North Pacific Stock, which corresponds 
to the Western North Pacific DPS and is listed as endangered, have an 
even smaller potential to occur

[[Page 74457]]

in the project location (2 percent, Wade, 2021).
    Humpback whales migrate to the North Pacific, including the 
Aleutian Islands, to feed after months of fasting in equatorial 
breeding grounds. Humpback whales generally travel alone or in small 
groups that persist only a few hours. Groups may stay together for 
longer in the summer in order to feed cooperatively. During the 2016 
and 2021 Shemya Island marine mammal surveys, seven humpback whales 
were observed in the project area (see application).

Minke Whale

    Minke whales occur in polar, temperate, and tropical waters 
worldwide in a range extending from the ice edge in the Arctic during 
the summer to near the equator during winter. However, they are known 
to prefer temperate to boreal waters due to the abundance of prey 
(Guerrero, 2008b). When comparing distribution and abundance in the 
years 2002, 2008, and 2010, it was found that that minke whales were 
scattered throughout all oceanographic domains: coastal, middle shelf, 
and outer shelf/slope (Muto et al., 2021). The minke whale mostly 
migrates seasonally and can travel long distances; although, some minke 
whale individuals and stocks have resident home ranges and are not 
highly migratory (Guerrero, 2008b). The Alaska Stock of minke whales 
are migratory and are common in the waters of the Bering Sea, Gulf of 
Alaska, and Southeast Alaska in the spring and summer (NMFS, 2023c).
    The distribution of minke whales vary according to age, sex, and 
reproductive status. Older mature males are commonly found in small 
social groups around the ice edge of polar regions during the summer 
feeding season. Comparatively, adult females will migrate farther into 
the higher latitudes but generally remain in coastal waters. Immature 
minke whales tend to be solitary and stay in lower latitudes during the 
summer (Guerrero, 2008b). Although the minke whale tends to be solitary 
or in groups of two to three individuals, they can congregate in larger 
groups containing up to 400 individuals at the higher latitude foraging 
areas (NOAA, 2021). During surveys in Alaska, minke whales are 
predominately observed alone (Wade et al., 2003; Waite, 2003). Breeding 
season typically occurs from December to March, but in some regions 
minke whales breed year-round. When migrating north in spring and 
summer, they will travel along in coastal waters, whereas in fall and 
winter, they move farther offshore (NMFS, 2023c). In 2003, a minke 
whale was observed in July when a sea otter survey was being conducted 
at Attu Island (Doroff et al., 2004), 28 mi to the west of Shemya 
Island. During the 2016 and 2021 Shemya Island marine mammal surveys, 
no minke whales were observed in the project area (see application).

Sperm Whale

    Sperm whales are the most sighted and recorded cetacean in marine 
mammal surveys in high latitude regions of the North Pacific, including 
the Bering Sea and the Aleutian Islands (Young et al., 2023). However, 
sperm whales exhibit sex-specific latitudinal segregation, where 
females and their young form social groups and are usually found in 
temperate and tropical latitudes, while males forage at higher 
latitudes and tends to only return to tropical and subtropical regions 
to breed (Whitehead, 2009). As such, males are more frequently 
encountered in the Aleutians than females; social groups typically 
occur in this area only during the winter when males are less likely to 
be present (Posdalijian, 2023).
    Sperm whales tend to occur offshore in submarine canyons at the 
edge of the continental shelf in water 1,000 m (3,300 ft) deep (Jaquet 
and Whitehead, 1996). They hunt for food during deep dives that 
routinely reach depths of 2,000 feet and can last for 45 minutes. 
Because sperm whales spend most of their time in deep waters, their 
diet consists of species such as squid, sharks, skates, and fish that 
also occupy deep ocean waters.
    The Aleutian Islands are considered a biologically important area 
(BIA) for feeding for sperm whale (Brower, 2022). This BIA overlaps 
with the project area and is active April through September. The BIA 
scored a three for importance and intensity, and a two for data support 
and boundary certainty, indicating that it is of high importance, has 
moderately certain boundaries, and moderate data to support the 
identification of the BIA (see Harrison et al. (2023) for additional 
information about the scoring process used to identify BIAs). The BIA 
was identified as having dynamic spatiotemporal variability.
    During the 2016 and 2021 marine mammal surveys completed on Shemya 
Island, four sperm whales were observed on a single day (see 
application).

Baird's Beaked Whale

    Baird's beaked whale occurs in the North Pacific and Bering Sea 
along the Aleutian Islands as well as the adjacent waters of the Gulf 
of Alaska, Sea of Okhotsk, and the Sea of Japan (Guerrero, 2008a). 
Within the North Pacific Ocean, Baird's beaked whales have been sighted 
north of 30[deg] N in deep, cold waters over the continental shelf 
(Muto et al., 2021), particularly in regions with 1,000 m (3,300 ft) or 
deeper contours, submarine canyons, and seamounts. However, they can be 
occasionally found in nearshore environments along narrow continental 
shelves. Baird's beaked whales migrate seasonally based on the 
temperature of surface water (NMFS, 2023a). They occur in waters of the 
continental slope during summer and fall months when surface water 
temperatures are the highest (Muto et al., 2021). They have also been 
observed in the nearshore waters of the Bering Sea and Okhotsk Sea in 
May to October (NMFS, 2023a). Baird's beaked whales are usually found 
in tight social groups (schools or pods) averaging between five and 20 
individuals, but they have occasionally been observed in larger groups 
of up to 50 animals.
    During the 2016 and 2021 Shemya Island marine mammal surveys, no 
Baird's beaked whales were observed in the project area (see 
application).

Stejneger's Beaked Whale

    Stejneger's beaked whale prefer cold, temperate, and subarctic 
waters of the North Pacific Ocean and are generally found in deep, 
offshore waters on or beyond the continental slope between 2,500 and 
5,000 ft. Most records are from Alaskan waters, and the Aleutian 
Islands appear to be its center of distribution (Mead, 1989; Wade et 
al., 2003).They are usually found in small, tight social groups 
averaging between 5 and 15 individuals. This whale is rarely sighted at 
sea, but they have been detected acoustically in the Aleutian waters in 
summer, fall, and spring (Baumann-Pickering et al., 2014; Muto, 2021). 
Most data on Stejneger's beaked whale have been collected and inferred 
from stranded individuals. Though most strandings in the Aleutians 
occur in the central portion of the island chain, there was a stranding 
of an adult male Stejneger's beaked whale on the southeast coast of 
Shemya Island on September 1, 2005 (Savage et al., 2021). During the 
2016 and 2021 marine mammal surveys completed on Shemya Island, no 
Stejneger's beaked whale were observed.

Killer Whale

    Killer whales occur in every ocean in the world and are the most 
widely distributed of all cetaceans. Along the west coast of North 
America, killer whales occur along the entire Alaska coast (Braham and 
Dahlheim, 1982).

[[Page 74458]]

This proposed IHA considers only the Eastern North Pacific Alaska 
Resident stock (Alaska Resident stock), and the Eastern North Pacific 
Gulf of Alaska, Aleutian Islands and Bering Sea Transient stocks 
because all other killer whale stocks occur outside the geographic area 
under consideration (Muto et al., 2021).
    There are three distinct ecotypes, or forms, of killer whales 
recognized: Resident, Transient, and Offshore. The three ecotypes 
differ morphologically, ecologically, behaviorally, and genetically. 
Spatial distribution has been shown to vary among the different 
ecotypes, with resident and, to a lesser extent, transient killer 
whales more commonly observed along the continental shelf, and offshore 
killer whales more commonly observed in pelagic waters (Rice et al., 
2021).
    When comparing movement, residents tend to have more predictable 
movements and the smallest home ranges and they return annually, 
whereas transients are less predictable due to their larger home ranges 
and quick transits through local areas. Offshore ecotypes have the 
largest home ranges that are generally farther offshore compared to the 
other two ecotypes. (Zimmerman and Small, 2008). Resident killer whales 
live in large, stable groups ranging normally from 5 to 50 individuals 
and up to 100 or more. They feed only on fish, especially Pacific 
salmon. Transient killer whales, on the other hand, hunt marine 
mammals, like pinnipeds and porpoises, in smaller groups of 10 
individuals or less (Forney and Wade, 2006).
    During the 2016 and 2021 marine mammal surveys at Shemya Island, 
Killer whales were frequently documented within the project area and 
around the island during these surveys. Within the project area alone, 
the average daily observation rate was 0.6 killer whales (see 
application).

Dall's Porpoise

    Dall's porpoises are widely distributed across the North Pacific 
Ocean, ranging from Japan to southern California and up to Alaska and 
the Bering Sea in coastal and pelagic waters between 28[deg] N and 
65[deg] N (Wells, 2008; Muto et al., 2021). They inhabit all strata on 
the continental shelf, slope, and pelagic waters with the greatest 
densities occurring in deeper inshore and slope habitats (Rone et al., 
2017). Throughout most of the eastern North Pacific they are present 
during all months of the year, although there may winter movements out 
of areas of ice like Prince William Sound and the Bering Sea or 
onshore-offshore movements along the west coast of the continental U.S. 
(Muto et al., 2021). Depending on morphology/type, geography, and 
seasonality, they have inshore-offshore and north-south migration 
patterns (NMFS, 2023b).
    They generally travel in groups of 10 to 20 individuals but can 
occur in groups with over hundreds of individuals (Wells, 2008). These 
groups appear to be fluid as they form and break-up during play and 
feeding.
    During the 2016 and 2021 Shemya Island marine mammal surveys, no 
Dall's porpoise were observed in the project area (see application)

Harbor Porpoise

    The Bering Sea stock of harbor porpoise occurs within the project 
area, ranging from throughout the Aleutian Islands and into all waters 
north of Unimak Pass. The harbor porpoise frequents nearshore waters 
and coastal embayments throughout their range, including bays, harbors, 
estuaries, and fjords less than 650 ft (198 m) deep (NMFS, 2023d). They 
are most often observed in groups of two or three. During the 2016 and 
2021 marine mammal surveys completed on Shemya Island, one group of two 
to three harbor porpoise were observed (see application).

Northern Fur Seal

    Northern fur seals occur from southern California north to the 
Bering Sea and west to the Sea of Okhotsk and Honshu Island, Japan. 
They are highly pelagic, spending most of their time each year alone at 
sea. During the summer breeding season, most of the worldwide 
population is found on the Pribilof Islands in the southern Bering Sea, 
with the remaining animals on rookeries in Russia, on Bogoslof Island 
in the southern Bering Sea, on San Miguel Island off southern 
California (Lander and Kajimura, 1982; NMFS, 1993), and on the Farallon 
Islands off central California. Non-breeding northern fur seals may 
occasionally haul out on land at other sites in Alaska, British 
Columbia, and on islets along the west coast of the United States 
(Fiscus, 1983).
    During the reproductive season, adult males usually are on shore 
during the 4-month period from May to August, although some may be 
present until November. Adult females are ashore during a 6-month 
period (June-November). Following their respective times ashore, Alaska 
northern fur seals of both genders the move south and remain at sea 
until the next breeding season (Roppel, 1984). Adult females and pups 
from the Pribilof Islands move through the Aleutian Islands into the 
North Pacific Ocean, often to the waters offshore of Oregon and 
California (Ream et al., 2005). Adult males generally move only as far 
south as the Gulf of Alaska in the eastern North Pacific (Kajimura, 
1984) and the Kuril Islands in the western North Pacific (Loughlin et 
al., 1999). In Alaska, pups are born during the summer months and leave 
the rookeries in the fall, on average around mid-November. They 
generally remain at sea for 22 months before returning to land (Kenyon 
and Wilke, 1953).
    During the 2016 and 2021 marine mammal surveys completed on Shemya 
Island, no northern fur seals were observed (see application).

Steller Sea Lion

    Steller sea lions in the project area are anticipated to be from 
the Western stock, which includes all Steller sea lions originating 
from rookeries west of Cape Suckling (144[deg] W longitude). The 
centers of abundance and distribution for western DPS Steller sea lions 
are located in the Gulf of Alaska and Aleutian Islands. At sea, Steller 
sea lions commonly occur near the 656-ft (200-m) depth contour but have 
been found from nearshore to well beyond the continental shelf 
(Kajimura and Loughlin, 1988). Sea lions move offshore to pelagic 
waters for feeding excursions.
    Steller sea lions are frequently observed around Shemya Island 
outside of the ensonified area, though only occasionally observed in 
low numbers in Alcan Harbor and Shemya Pass (see application). The 
ensonified area would intersect with the aquatic zone of Steller sea 
lion haulouts designated as critical habitat. The Shemya Island Major 
Haulout is 2.75 nmi to the east of the project site, Alaid Island Major 
Haulout is 5 nmi northwest of the project site, and Attu/Chirikof Point 
Major Haulout is 24 nmi to the northwest of the project site. However, 
no Steller sea lions have been observed on the Shemya Island Major 
Haulout during surveys completed between 2015 and 2017, and only one 
Steller sea lion was observed at Attu/Chirkock Point during surveys 
conducted during the same time frame. An average of 68 non-pups and 7 
pups were observed annually during this time at Alaid Island Major 
Haulout (see application).

Harbor Seal

    Harbor seals inhabit coastal and estuarine waters off Alaska. They 
haul out on rocks, reefs, beaches, and drifting glacial ice. They are 
generally non-migratory, with local movements

[[Page 74459]]

associated with such factors as tides, weather, season, food 
availability, and reproduction (Muto et al., 2021). They are 
opportunistic feeders and often adjust their distribution to take 
advantage of locally and seasonally abundant prey (Womble et al., 2010; 
Allen and Angliss, 2015). Although they tend to be solitary when in the 
water, they can form groups of about 30 or less individuals of both 
sexes and all ages when hauling out. Harbor seals haul out to rest 
periodically, give birth or nurse.
    Harbor seals in the project area are recognized as part of the 
Aleutian Island stock, occurring along the entire Aleutian island chain 
from Attu Island to Ugamak Island. Pupping season in the Aleutian 
Islands is occurs between mid-June to mid-July. (Sease, 1992). Harbor 
seals haul out on beaches all around Shemya Island, with largest 
numbers observed on the east side of the island, away from the 
ensonified area. However, harbor seals are occasionally observed 
occurring inside the ensonified area. During the 2016 and 2021 marine 
mammal surveys completed on Shemya Island, an average of 0.45 harbor 
seals were observed each day.

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 (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65-
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in table 3.

                  Table 3--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
            Hearing Group                 Generalized Hearing Range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen  7 Hz to 35 kHz
 whales).
Mid-frequency (MF) cetaceans          150 Hz to 160 kHz
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true   275 Hz to 160 kHz
 porpoises, Kogia, river dolphins,
 Cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater)    50 Hz to 86 kHz
 (true seals).
Otariid pinnipeds (OW) (underwater)   60 Hz to 39 kHz
 (sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65-dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al., 2007) and PW pinniped (approximation).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section provides a discussion of the ways in which components 
of the specified activity may impact marine mammals and their habitat. 
The Estimated Take of Marine Mammals section later in this document 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The Negligible Impact Analysis 
and Determination section considers the content of this section, the 
Estimated Take of Marine Mammals section, and the Proposed Mitigation 
section, to draw conclusions regarding the likely impacts of these 
activities on the reproductive success or survivorship of individuals 
and whether those impacts are reasonably expected to, or reasonably 
likely to, adversely affect the species or stock through effects on 
annual rates of recruitment or survival.
    Acoustic effects on marine mammals during the specified activity 
can occur from impact and vibratory pile driving and removal and DTH. 
The effects of underwater noise from USAF's proposed activities have 
the potential to result in Level A harassment and Level B harassment of 
marine mammals.

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound is defined as the all-encompassing 
sound in a given place and is usually a composite of sound from many 
sources both near and far (American National Standards Institute 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

[[Page 74460]]

given frequency and location can vary by 10 to 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 (American National Standards Institute (ANSI), 1986; National 
Institute of Occupational Safety and Health (NIOSH), 1998; NMFS, 2018). 
Non-impulsive sounds (e.g., aircraft, machinery operations such as 
drilling or dredging, vibratory pile driving, and active sonar systems) 
can be broadband, narrowband or tonal, brief or prolonged (continuous 
or intermittent), and typically do not have the high peak sound 
pressure with rapid rise/decay time that impulsive sounds do (ANSI, 
1995; NIOSH, 1998; NMFS, 2018). The distinction between these two sound 
types is important because they have differing potential to cause 
physical effects, particularly with regard to hearing (e.g., Ward 1997 
in Southall et al., 2007).
    Three types of hammers would be used on this project: impact, 
vibratory, and DTH. Impact hammers operate by repeatedly dropping and/
or pushing a heavy piston onto a pile to drive the pile into the 
substrate. Sound generated by impact hammers is characterized by rapid 
rise times and high peak levels, a potentially injurious combination 
(Hastings and Popper, 2005). Vibratory hammers install piles by 
vibrating them and allowing the weight of the hammer to push them into 
the sediment. Vibratory hammers produce significantly less sound than 
impact hammers. Peak Sound Pressure Levels (SPLs) may be 180 dB or 
greater, but are generally 10 to 20 dB lower than SPLs generated during 
impact pile driving of the same-sized pile (Oestman et al., 2009). Rise 
time is slower, reducing the probability and severity of injury, and 
sound energy is distributed over a greater amount of time (Nedwell and 
Edwards, 2002; Carlson et al., 2005).
    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 to the DTH hammer to increase speed of 
progress through the substrate (i.e., it is similar to a ``hammer 
drill'' hand tool). The sounds produced by the DTH method contain both 
a continuous, non-impulsive component from the drilling action and an 
impulsive component from the hammering effect. Therefore, we treat DTH 
systems as both impulsive and continuous, non-impulsive sound source 
types simultaneously.
    The likely or possible impacts of USAF's proposed activities on 
marine mammals could be generated from both non-acoustic and acoustic 
stressors. Potential non-acoustic stressors include the physical 
presence of the equipment, vessels, and personnel; however, any impacts 
to marine mammals are expected to primarily be acoustic in nature. 
Acoustic stressors include effects of heavy equipment operation during 
pile installation and removal and DTH.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving and removal and DTH equipment is the 
primary means by which marine mammals may be harassed from USAF's 
specified activities. In general, animals exposed to natural or 
anthropogenic sound may experience behavioral, physiological, and/or 
physical effects, ranging in magnitude from none to severe (Southall et 
al., 2007). Generally, exposure to pile driving and removal 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, auditory threshold shifts. 
Exposure to anthropogenic noise can also lead to non-observable 
physiological responses such as an increase in stress hormones. 
Additional noise in a marine mammal's habitat can mask acoustic cues 
used by marine mammals to carry out daily functions such as 
communication and predator and prey detection. The effects of pile 
driving and removal and DTH noise on marine mammals are dependent on 
several factors, including, but not limited to, sound type (e.g., 
impulsive vs. non-impulsive), the species, age and sex class (e.g., 
adult male vs. mother with calf), duration of exposure, the distance 
between the pile and the animal, received levels, behavior at time of 
exposure, and previous history with exposure (Wartzok et al., 2003; 
Southall et al., 2007). Here we discuss physical auditory effects 
(threshold shifts) followed by behavioral effects and potential impacts 
on habitat.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018), 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).
    Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent, 
irreversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). Available data 
from humans and other terrestrial mammals indicate that a 40-dB 
threshold shift approximates PTS onset (Ward et al., 1958; Ward et al., 
1959; Ward, 1960; Kryter et al., 1966; Miller, 1974; Henderson et al., 
2008). PTS levels for marine mammals are estimates, because there are 
limited empirical data measuring PTS in marine mammals (e.g., Kastak et 
al., 2008), 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), a TTS of 6 dB is considered the minimum 
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing

[[Page 74461]]

ability (Schlundt et al., 2000; Finneran et al., 2000; Finneran et al., 
2002). As described in Finneran (2016), marine mammal studies have 
shown the amount of TTS increases with cumulative sound exposure level 
(SEL<INF>cum</INF>) in an accelerating fashion: At low exposures with 
lower SEL<INF>cum,</INF> the amount of TTS is typically small and the 
growth curves have shallow slopes. At exposures with higher 
SEL<INF>cum,</INF> the growth curves become steeper and approach linear 
relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced, TTS can have effects on marine mammals ranging 
from discountable to serious (similar to those discussed in Masking, 
below). For example, a marine mammal may be able to readily compensate 
for a brief, relatively small amount of TTS in a non-critical frequency 
range that takes place during a time when the animal is traveling 
through the open ocean, where ambient noise is lower and there are not 
as many competing sounds present. Alternatively, a larger amount and 
longer duration of TTS sustained during time when communication is 
critical for successful mother/calf interactions could have more 
serious impacts. We note that reduced hearing sensitivity as a simple 
function of aging has been observed in marine mammals, as well as 
humans and other taxa (Southall et al., 2007), so we can infer that 
strategies exist for coping with this condition to some degree, though 
likely not without cost.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus 
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena 
asiaeorientalis) and five species of pinnipeds exposed to a limited 
number of sound sources (i.e., mostly tones and octave-band noise) in 
laboratory settings (Finneran, 2015). TTS was not observed in trained 
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to 
impulsive noise at levels matching previous predictions of TTS onset 
(Reichmuth et al., 2016). In general, harbor seals and harbor porpoises 
have a lower TTS onset than other measured pinniped or cetacean species 
(Finneran, 2015). Additionally, the existing marine mammal TTS data 
come from a limited number of individuals within these species. No data 
are available on noise-induced hearing loss for mysticetes. For 
summaries of data on TTS in marine mammals or for further discussion of 
TTS onset thresholds, please see Southall et al. (2007), Finneran and 
Jenkins (2012), Finneran (2015), and table 5 in NMFS (2018).
    Activities for this project include impact and vibratory pile 
driving, vibratory pile removal, and DTH activities. There would likely 
be pauses in activities producing the sound during each day. Given 
these pauses and the fact that many marine mammals are likely moving 
through the project areas and not remaining for extended periods of 
time, the potential for threshold shift declines.
    Behavioral harassment--Exposure to noise from pile driving and 
removal and DTH also has the potential to behaviorally disturb marine 
mammals. Available studies show wide variation in response to 
underwater sound; therefore, it is difficult to predict specifically 
how any given sound in a particular instance might affect marine 
mammals perceiving the signal. If a marine mammal does react briefly to 
an underwater sound by changing its behavior or moving a small 
distance, the impacts of the change are unlikely to be significant to 
the individual, let alone the stock or population. However, if a sound 
source displaces marine mammals from an important feeding or breeding 
area for a prolonged period, impacts on individuals and populations 
could be significant [e.g., Lusseau and Bejder, 2007; Weilgart, 2007; 
National Research Council (NRC), 2005].
    The following subsections provide examples of behavioral responses 
that provide an idea of the variability in behavioral responses that 
would be expected given the differential sensitivities of marine mammal 
species to sound and the wide range of potential acoustic sources to 
which a marine mammal may be exposed. Behavioral responses that could 
occur for a given sound exposure should be determined from the 
literature that is available for each species, or extrapolated from 
closely related species when no information exists, along with 
contextual factors. Available studies show wide variation in response 
to underwater sound; therefore, it is difficult to predict specifically 
how any given sound in a particular instance might affect marine 
mammals perceiving the signal. There are broad categories of potential 
response, which we describe in greater detail here, that include 
alteration of dive behavior, alteration of foraging behavior, effects 
to respiration, interference with or alteration of vocalization, 
avoidance, and flight.
    Pinnipeds may increase their haul out time, possibly to avoid in-
water disturbance (Thorson and Reyff, 2006). Behavioral reactions can 
vary not only among individuals but also within an individual, 
depending on previous experience with a sound source, context, and 
numerous other factors (Ellison et al., 2012), and can vary depending 
on characteristics associated with the sound source (e.g., whether it 
is moving or stationary, number of sources, distance from the source). 
In general, pinnipeds seem more tolerant of, or at least habituate more 
quickly to, potentially disturbing underwater sound than do cetaceans, 
and generally seem to be less responsive to exposure to industrial 
sound than most cetaceans.
    Alteration of Dive Behavior--Changes in dive behavior can vary 
widely, and may consist of increased or decreased dive times and 
surface intervals as well as changes in the rates of ascent and descent 
during a dive (e.g., Frankel and Clark, 2000; Costa et al., 2003; Ng 
and Leung, 2003; Nowacek et al., 2004; Goldbogen et al., 2013). Seals 
exposed to non-impulsive sources with a received sound pressure level 
within the range of calculated exposures (142-193 dB re 1 [mu]Pa), have 
been shown to change their behavior by modifying diving activity and 
avoidance of the sound source (G[ouml]tz and Janik, 2010; Kvadsheim et 
al., 2010). Variations in dive behavior may reflect interruptions in 
biologically significant activities (e.g., foraging) or they may be of 
little biological significance. The impact of an alteration to dive 
behavior resulting from an acoustic exposure depends on what the animal 
is doing at the time of the exposure and the type and magnitude of the 
response.
    Alteration of Feeding Behavior--Disruption of feeding behavior can 
be difficult to correlate with anthropogenic sound exposure, so it is 
usually inferred by observed displacement from known foraging areas, 
the appearance of secondary indicators (e.g., bubble nets or sediment 
plumes), or changes in dive behavior. As for other types of behavioral 
response, the frequency, duration, and temporal pattern of signal 
presentation, as well as differences in species sensitivity, are likely 
contributing factors to differences in response in any given 
circumstance (e.g., Croll et al., 2001; Nowacek et al., 2004; Madsen et 
al., 2006; Yazvenko et al., 2007; Melc[oacute]n et al., 2012). In 
addition, behavioral state of the animal plays a role in the type and 
severity of a behavioral response, such as disruption to foraging 
(e.g., Silve et al., 2016; Wensveen et al., 2017). An evaluation of 
whether foraging disruptions would be likely to incur fitness 
consequences considers temporal

[[Page 74462]]

and spatial scale of the activity in the context of the available 
foraging habitat and, in more severe cases may necessitate 
consideration of information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal. Goldbogen et al. (2013) indicate that disruption 
of feeding and displacement could impact individual fitness and health. 
However, for this to be true, we would have to assume that an 
individual could not compensate for this lost feeding opportunity by 
either immediately feeding at another location, by feeding shortly 
after cessation of acoustic exposure, or by feeding at a later time. 
There is no indication this is the case here, particularly since prey 
would likely still be available in the environment in most cases 
following the cessation of acoustic exposure.
    Respiration--Respiration naturally varies with different behaviors, 
and variations in respiration rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Studies with captive harbor porpoises showed increased 
respiration rates upon introduction of acoustic alarms (Kastelein et 
al., 2001; Kastelein et al., 2006a) and emissions for underwater data 
transmission (Kastelein et al., 2005). Various studies also have shown 
that species and signal characteristics are important factors in 
whether respiration rates are unaffected or change, again highlighting 
the importance in understanding species differences in the tolerance of 
underwater noise when determining the potential for impacts resulting 
from anthropogenic sound exposure (e.g., Kastelein et al., 2005; 
Kastelein et al., 2006; Kastelein et al., 2018; Gailey et al., 2007; 
Isojunno et al., 2018).
    Vocalization--Marine mammals vocalize for different purposes and 
across multiple modes, such as whistling, echolocation click 
production, calling, and singing. Changes in vocalization behavior in 
response to anthropogenic noise can occur for any of these modes and 
may result from a need to compete with an increase in background noise 
or may reflect increased vigilance or a startle response. For example, 
in the presence of potentially masking signals, humpback whales and 
killer whales (Orcinus orca) have been observed to increase the length 
of their songs (Miller et al., 2000; Fristrup et al., 2003; Foote et 
al., 2004), while right whales have been observed to shift the 
frequency content of their calls upward while reducing the rate of 
calling in areas of increased anthropogenic noise (Parks et al., 2007; 
Rolland et al., 2012). Killer whales off the northwestern coast of the 
United States have been observed to increase the duration of primary 
calls once a threshold in observing vessel density (e.g., whale 
watching) was reached, which has been suggested as a response to 
increased masking noise produced by the vessels (Foote et al., 2004; 
NOAA, 2014). In some cases, however, animals may cease or alter sound 
production in response to underwater sound (e.g., Bowles et al., 1994; 
Castellote et al., 2012; Cerchio et al., 2014). Studies also 
demonstrate that even low levels of noise received far from the noise 
source can induce changes in vocalization and/or behavioral responses 
(Blackwell et al., 2013; Blackwell et al., 2015).
    Avoidance--Avoidance is the displacement of an individual from an 
area or migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). Avoidance is qualitatively 
different from the flight response, but also differs in the magnitude 
of the response (i.e., directed movement, rate of travel, etc.). Often 
avoidance is temporary, and animals return to the area once the noise 
has ceased. Acute avoidance responses have been observed in captive 
porpoises and pinnipeds exposed to a number of different sound sources 
(Kastelein et al., 2001; Finneran et al., 2003; Kastelein et al., 
2006a; Kastelein et al., 2006b; Kastelein et al., 2015b; Kastelein et 
al., 2015c; Kastelein et al., 2018). Short-term avoidance of seismic 
surveys, low frequency emissions, and acoustic deterrents have also 
been noted in wild populations of odontocetes (Bowles et al., 1994; 
Goold, 1996; Goold and Fish, 1998; Morton and Symonds, 2002; Hiley et 
al., 2021) and to some extent in mysticetes (Malme et al., 1984; 
McCauley et al., 2000; Gailey et al., 2007). Longer-term displacement 
is possible, however, which may lead to changes in abundance or 
distribution patterns of the affected species in the affected region if 
habituation to the presence of the sound does not occur (e.g., 
Blackwell et al., 2004; Bejder et al., 2006; Teilmann et al., 2006).
    Forney et al. (2017) described the potential effects of noise on 
marine mammal populations with high site fidelity, including 
displacement and auditory masking. In cases of western gray whales 
(Eschrichtius robustus) and beaked whales (Ziphius cavirostris), 
anthropogenic effects in areas where they are resident or exhibit site 
fidelity could cause severe biological consequences, in part because 
displacement may adversely affect foraging rates, reproduction, or 
health, while an overriding instinct to remain in the area could lead 
to more severe acute effects. Avoidance of overlap between disturbing 
noise and areas and/or times of particular importance for sensitive 
species may be critical to avoiding population-level impacts because 
(particularly for animals with high site fidelity) there may be a 
strong motivation to remain in the area despite negative impacts.
    Flight Response--A flight response is a dramatic change in normal 
movement to a directed and rapid movement away from the perceived 
location of a sound source. The flight response differs from other 
avoidance responses in the intensity of the response (e.g., directed 
movement, rate of travel). Relatively little information on flight 
responses of marine mammals to anthropogenic signals exist, although 
observations of flight responses to the presence of predators have 
occurred (Connor and Heithaus, 1996). The result of a flight response 
could range from brief, temporary exertion and displacement from the 
area where the signal provokes flight to, in extreme cases, marine 
mammal strandings (Evans and England, 2001). There are limited data on 
flight response for marine mammals in water; however, there are 
examples of this response in species on land. For instance, the 
probability of flight responses in Dall's sheep Ovis dalli dalli (Frid, 
2003), hauled out ringed seals (Phoca hispida) (Born et al., 1999), 
Pacific brant (Branta bernicla nigricans), and Canada geese (B. 
canadensis) increased as a helicopter or fixed-wing aircraft more 
directly approached groups of these animals (Ward et al., 1999). 
However, it should be noted that response to a perceived predator does 
not necessarily invoke flight (Ford and Reeves, 2008), and whether 
individuals are solitary or in groups may influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been observed in marine mammals, but studies 
involving fish and terrestrial animals have shown that increased

[[Page 74463]]

vigilance may substantially reduce feeding rates and efficiency (e.g., 
Beauchamp and Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 
2011). In addition, chronic disturbance can cause population declines 
through reduction of fitness (e.g., decline in body condition) and 
subsequent reduction in reproductive success, survival, or both (e.g., 
Harrington and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998).
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than 1 day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    To assess the strength of behavioral changes and responses to 
external sounds and SPLs associated with changes in behavior, Southall 
et al. (2007) developed and utilized a severity scale, which is a 10-
point scale ranging from no effect (labeled 0), effects not likely to 
influence vital rates (low; labeled from one to three), effects that 
could affect vital rates (moderate; labeled from four to six), to 
effects that were thought likely to influence vital rates (high; 
labeled from seven to nine). Southall et al. (2021) updated the 
severity scale by integrating behavioral context (i.e., survival, 
reproduction, and foraging) into severity assessment. For non-impulsive 
sounds (i.e., similar to the sources used during the proposed action), 
data suggest that exposures of pinnipeds to sources between 90 and 140 
dB re 1 [mu]Pa do not elicit strong behavioral responses; no data were 
available for exposures at higher received levels for Southall et al. 
(2007) to include in the severity scale analysis. Reactions of harbor 
seals were the only available data for which the responses could be 
ranked on the severity scale. For reactions that were recorded, the 
majority (17 of 18 individuals/groups) were ranked on the severity 
scale as a 4 (defined as moderate change in movement, brief shift in 
group distribution, or moderate change in vocal behavior) or lower. The 
remaining response was ranked as a 6 (defined as minor or moderate 
avoidance of the sound source).
    Habituation--Habituation can occur when an animal's response to a 
stimulus wanes with repeated exposure, usually in the absence of 
unpleasant associated events (Wartzok et al., 2003). Animals are most 
likely to habituate to sounds that are predictable and unvarying. It is 
important to note that habituation is appropriately considered as a 
``progressive reduction in response to stimuli that are perceived as 
neither aversive nor beneficial,'' rather than as, more generally, 
moderation in response to human disturbance (Bejder et al., 2009). The 
opposite process is sensitization, when an unpleasant experience leads 
to subsequent responses, often in the form of avoidance, at a lower 
level of exposure. As noted, behavioral state may affect the type of 
response. For example, animals that are resting may show greater 
behavioral change in response to disturbing sound levels than animals 
that are highly motivated to remain in an area for feeding (Richardson 
et al., 1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments 
with captive marine mammals have 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 impulsive sound sources (typically seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds, 2002; Richardson et al., 1995; Nowacek et al., 2007).
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness. Neuroendocrine stress responses often involve the 
hypothalamus-pituitary-adrenal system. Virtually all neuroendocrine 
functions that are affected by stress--including immune competence, 
reproduction, metabolism, and behavior--are regulated by pituitary 
hormones. Stress-induced changes in the secretion of pituitary hormones 
have been implicated in failed reproduction, altered metabolism, 
reduced immune competence, and behavioral disturbance (e.g., Moberg, 
1987; Blecha, 2000). Increases in the circulation of glucocorticoids 
are also equated with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003), however 
distress is an unlikely result of these projects based on observations 
of marine mammals during previous, similar projects.
    Auditory Masking--Sound can disrupt behavior through masking, or 
interfering with, an animal's ability to detect, recognize, or 
discriminate

[[Page 74464]]

between acoustic signals of interest (e.g., those used for 
intraspecific communication and social interactions, prey detection, 
predator avoidance, navigation) (Richardson et al., 1995). Masking 
occurs when the receipt of a sound is interfered with by another 
coincident sound at similar frequencies and at similar or higher 
intensity, and may occur whether the sound is natural (e.g., snapping 
shrimp, wind, waves, precipitation) or anthropogenic (e.g., pile 
driving, shipping, sonar, seismic exploration) in origin. The ability 
of a noise source to mask biologically important sounds depends on the 
characteristics of both the noise source and the signal of interest 
(e.g., signal-to-noise ratio, temporal variability, direction), in 
relation to each other and to an animal's hearing abilities (e.g., 
sensitivity, frequency range, critical ratios, frequency 
discrimination, directional discrimination, age or TTS hearing loss), 
and existing ambient noise and propagation conditions. Masking of 
natural sounds can result when human activities produce high levels of 
background sound at frequencies important to marine mammals. 
Conversely, if the background level of underwater sound is high (e.g., 
on a day with strong wind and high waves), an anthropogenic sound 
source would not be detectable as far away as would be possible under 
quieter conditions and would itself be masked.
    Airborne Acoustic Effects--Pinnipeds that occur near the project 
site could be exposed to airborne sounds associated with pile driving 
and removal that have the potential to cause behavioral harassment, 
depending on their distance from pile driving activities. Cetaceans are 
not expected to be exposed to airborne sounds that would result in 
harassment as defined under the MMPA. Airborne noise would primarily be 
an issue for pinnipeds that are swimming or hauled out near the project 
site within the range of noise levels elevated above the acoustic 
criteria. We recognize that pinnipeds in the water could be exposed to 
airborne sound that may result in behavioral harassment when looking 
with their heads above water. Most likely, airborne sound would cause 
behavioral responses similar to those discussed above in relation to 
underwater sound. For instance, anthropogenic sound could cause hauled 
out pinnipeds to exhibit changes in their normal behavior, such as 
reduction in vocalizations, or cause them to temporarily abandon the 
area and move further from the source. However, these animals would 
likely previously have been `taken' because of exposure to underwater 
sound above the behavioral harassment thresholds, which are generally 
larger than those associated with airborne sound. Thus, the behavioral 
harassment of these animals is already accounted for in these estimates 
of potential take. Therefore, we do not believe that authorization of 
additional incidental take resulting from airborne sound for pinnipeds 
is warranted, and airborne sound is not discussed further.

Marine Mammal Habitat Effects

    USAF's proposed construction activities could have localized, 
temporary impacts on marine mammal habitat, including prey, by 
increasing in-water sound pressure levels and slightly decreasing water 
quality. Increased noise levels may affect acoustic habitat (see 
Masking discussion above) and adversely affect marine mammal prey in 
the vicinity of the project areas (see discussion below). Elevated 
levels of underwater noise would ensonify the project areas where both 
fishes and mammals occur and could affect foraging success. 
Additionally, marine mammals may avoid the area during 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 Construction Effects on Potential Prey--Construction 
activities would produce continuous (i.e., vibratory pile driving and 
DTH) and intermittent (i.e., impact driving and DTH) sounds. Sound may 
affect marine mammals through impacts on the abundance, behavior, or 
distribution of prey species (e.g., crustaceans, cephalopods, fish, 
zooplankton). Marine mammal prey varies by species, season, and 
location. Here, we describe studies regarding the effects of noise on 
known marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay, 
2009). Depending on their hearing anatomy and peripheral sensory 
structures, which vary among species, fishes hear sounds using pressure 
and particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    Fish react to sounds that are especially strong and/or intermittent 
low-frequency sounds, and behavioral responses such as flight or 
avoidance are the most likely effects. Short duration, sharp sounds can 
cause overt or subtle changes in fish behavior and local distribution. 
The reaction of fish to noise depends on the physiological state of the 
fish, past exposures, motivation (e.g., feeding, spawning, migration), 
and other environmental factors. Hastings and Popper (2005) identified 
several studies that suggest fish may relocate to avoid certain areas 
of sound energy. Additional studies have documented effects of pile 
driving on fish; several are based on studies in support of large, 
multiyear bridge construction projects (e.g., Scholik and Yan, 2001; 
Scholik and Yan, 2002; Popper and Hastings, 2009). Several studies have 
demonstrated that impulse sounds might affect the distribution and 
behavior of some fishes, potentially impacting foraging opportunities 
or increasing energetic costs (e.g., Fewtrell and McCauley, 2012; 
Pearson et al., 1992; Skalski et al., 1992; Santulli et al., 1999; 
Paxton et al., 2017). However, some studies have shown no or slight 
reaction to impulse sounds (e.g., Pena et al., 2013; Wardle et al., 
2001; Jorgenson and Gyselman, 2009).
    SPLs of sufficient strength have been known to cause injury to fish 
and fish mortality. However, in most fish species, hair cells in the 
ear continuously regenerate and loss of auditory function likely is 
restored when damaged cells are replaced with new cells. Halvorsen et 
al. (2012a) showed that a TTS of 4 to 6 dB was recoverable within 24 
hours for one species. Impacts would be most severe when the individual 
fish is close to the source and when the duration of exposure is long. 
Injury caused by barotrauma can range from slight to severe and can 
cause death, and is most likely for fish with swim bladders. Barotrauma 
injuries have been documented during controlled exposure to impact pile 
driving (Halvorsen et al., 2012b; Casper et al., 2013).
    The most likely impact to fishes from pile driving activities at 
the project area would be temporary behavioral avoidance of the area. 
The duration of fish avoidance of this area after pile driving stops is 
unknown, but a rapid return to normal recruitment, distribution, and 
behavior is anticipated.

[[Page 74465]]

    Construction activities have the potential to have adverse impacts 
on forage fish in the project area in the form of increased turbidity. 
Forage fish form a significant prey base for many marine mammal species 
that occur in the project area. Turbidity within the water column has 
the potential to reduce the level of oxygen in the water and irritate 
the gills of prey fish in the proposed project area. However, fish in 
the proposed project area would be able to move away from and avoid the 
areas where increase turbidity may occur. Given the limited area 
affected and ability of fish to move to other areas, any effects on 
forage fish are expected to be minor or negligible.
    In summary, given the short daily duration of sound associated with 
individual pile driving and removal events and the relatively small 
areas being affected, pile driving and removal activities associated 
with the proposed actions are not likely to have a permanent, adverse 
effect on any fish habitat, or populations of fish species. Any 
behavioral avoidance by fish of the disturbed area would still leave 
significantly large areas of fish and marine mammal foraging habitat in 
the nearby vicinity. Thus, we conclude that impacts of the specified 
activities are not likely to have more than short-term adverse effects 
on any prey habitat or populations of prey species. Further, any 
impacts to marine mammal habitat are not expected to result in 
significant or long-term consequences for individual marine mammals, or 
to contribute to adverse impacts on their populations.

Estimated Take of Marine Mammals

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers,'' and the negligible impact 
determinations.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which: (i) has the potential to injure 
a marine mammal or marine mammal stock in the wild (Level A 
harassment); or (ii) has the potential to disturb a marine mammal or 
marine mammal stock in the wild by causing disruption of behavioral 
patterns, including, but not limited to, migration, breathing, nursing, 
breeding, feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as use 
of the acoustic sources (i.e., impact and vibratory pile driving and 
removal and DTH) has the potential to result in disruption of 
behavioral patterns for individual marine mammals. There is also some 
potential for auditory injury (Level A harassment) to result, primarily 
for mysticetes and/or high frequency species and/or phocids because 
predicted auditory injury zones are larger than for mid-frequency 
species and/or otariids. Auditory injury is unlikely to occur for other 
groups. The proposed mitigation and monitoring measures are expected to 
minimize the severity of the taking to the extent practicable.
    As described previously, no serious injury or mortality is 
anticipated or proposed to be authorized for this activity. Below we 
describe how the proposed take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) acoustic thresholds above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed or incur some degree of permanent hearing impairment; (2) the 
area or volume of water that will be ensonified above these levels in a 
day; (3) the density or occurrence of marine mammals within these 
ensonified areas; and, (4) the number of days of activities. We note 
that while these factors can contribute to a basic calculation to 
provide an initial prediction of potential takes, additional 
information that can qualitatively inform take estimates is also 
sometimes available (e.g., previous monitoring results or average group 
size). Below, we describe the factors considered here in more detail 
and present the proposed take estimates.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007; Southall et al., 2021; Ellison et 
al., 2012). Based on what the available science indicates and the 
practical need to use a threshold based on a metric that is both 
predictable and measurable for most activities, NMFS typically uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment. NMFS generally predicts that marine 
mammals are likely to be behaviorally harassed in a manner considered 
to be Level B harassment when exposed to underwater anthropogenic noise 
above root-mean-squared pressure received levels (RMS SPL) of 120 dB 
(referenced to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., 
vibratory pile driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa 
for non-explosive impulsive (e.g., seismic airguns) or intermittent 
(e.g., scientific sonar) sources. Generally speaking, Level B 
harassment take estimates based on these behavioral harassment 
thresholds are expected to include any likely takes by TTS as, in most 
cases, the likelihood of TTS occurs at distances from the source less 
than those at which behavioral harassment is likely. TTS of a 
sufficient degree can manifest as behavioral harassment, as reduced 
hearing sensitivity and the potential reduced opportunities to detect 
important signals (conspecific communication, predators, prey) may 
result in changes in behavior patterns that would not otherwise occur. 
USAF's proposed activity includes the use of continuous (vibratory pile 
driving and removal and DTH) and impulsive (impact pile driving and 
DTH) sources, and therefore the RMS SPL thresholds of 120 and 160 dB re 
1 [mu]Pa is/are applicable.
    Level A harassment--NMFS' ``Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing'' (Version 2.0, 
Technical Guidance, 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive). USAF's 
proposed activity includes the use of impulsive (impact pile driving 
and DTH) and non-impulsive (vibratory pile driving and removal and DTH) 
sources.
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/

[[Page 74466]]

marine-mammal-acoustic-technical-guidance.

                     Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                     PTS onset acoustic thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;   Cell 2: LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;   Cell 8: LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;   Cell 10: LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and cumulative sound exposure level (LE) has
  a reference value of 1[mu]Pa\2\s. In this Table, thresholds are abbreviated to reflect American National
  Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as incorporating
  frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
  being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
  hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
  designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
  that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
  exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
  is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that are used in estimating the area ensonified above the 
acoustic thresholds, including source levels and transmission loss 
coefficient.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., pile driving and removal and 
DTH). The maximum (underwater) area ensonified above the thresholds for 
behavioral harassment referenced above is 1286 km\2\ (496 mi\2\), and 
the calculated distance to the farthest behavioral harassment isopleth 
is approximately 39,811 m (24,737.4 mi).
    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 piles available in the literature. Source levels for each 
pile size and activity are presented in table 5. Source levels for 
vibratory installation and removal of piles of the same diameter are 
assumed to be the same.
    NMFS recommends treating DTH systems as both impulsive and 
continuous, non-impulsive sound source types simultaneously. Thus, 
impulsive thresholds are used to evaluate Level A harassment, and 
continuous thresholds are used to evaluate Level B harassment. With 
regards to DTH mono-hammers, NMFS recommends proxy levels for Level A 
harassment based on available data regarding DTH systems of similar 
sized piles and holes (Denes et al., 2019; Reyff and Heyvaert, 2019; 
Reyff, 2020; Heyvaert and Reyff, 2021) (table 1 includes number of 
piles and duration; table 5 includes sound pressure and sound exposure 
levels for each pile type).

   Table 5--Estimates of Mean Underwater Sound Levels Generated During
 Vibratory and Impact Pile Installation, DTH, and Vibratory Pile Removal
------------------------------------------------------------------------
                               SSL at 10 m dB
  Continuous sound sources          rms            Literature source
------------------------------------------------------------------------
                            Vibratory Hammer
------------------------------------------------------------------------
42-inch steel piles.........            168.2  Port of Anchorage Test
                                                Pile Program (Table 16
                                                in Austin et al., 2016).
30-inch steel piles.........              166  * NMFS Analysis (C.
                                                Hotchkin, April 24,
                                                2023).
------------------------------------------------------------------------
                                   DTH
------------------------------------------------------------------------
42-inch steel piles.........              174  Reyff & Heyvaert, 2019;
                                                Reyff, 2020.
30-inch steel piles.........              174  Reyff & Heyvaert, 2019;
                                                Reyff, 2020.
------------------------------------------------------------------------


 
     Impulsive sound sources           dB rms          dB SEL          dB peak           Literature source
----------------------------------------------------------------------------------------------------------------
                                                  Impact Hammer
----------------------------------------------------------------------------------------------------------------
42-inch steel piles..............             192             179             213  Caltrans, 2020.
----------------------------------------------------------------------------------------------------------------
30-inch steel piles..............             191             177             212  Caltrans, 2020.
----------------------------------------------------------------------------------------------------------------
                                                       DTH
----------------------------------------------------------------------------------------------------------------
42-inch steel piles..............             N/A             164             194  Reyff & Heyvaert, 2019;
                                                                                    Reyff, 2020; Denes et al.,
                                                                                    2019.

[[Page 74467]]

 
30-inch steel piles..............             N/A             164             194  Reyff & Heyvaert, 2019;
                                                                                    Reyff, 2020; Denes et al.,
                                                                                    2019.
----------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; DTH = down-the-hole drilling; rms = root mean square; SEL = sound exposure
  level.
* NMFS generated this source level by completing a completed a comprehensive review of source levels relevant to
  Southeast Alaska; NMFS compiled all available data from Puget Sound and Southeast Alaska and adjusted the data
  to standardize distance from the measured pile to 10 m. NMFS then calculated average source levels for each
  project and for each pile type. NMFS weighted impact pile driving project averages by the number of strikes
  per pile following the methodology in Navy (2015).

    Transmission loss (TL) is the decrease in acoustic intensity as an 
acoustic pressure wave propagates out from a source. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. The general formula for underwater TL is:

TL = B * Log10 (R1/R2),

where

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

    Absent site-specific acoustical monitoring with differing measured 
transmission loss, a practical spreading value of 15 is used as the 
transmission loss coefficient in the above formula. Site-specific 
transmission loss data for the Shemya Island 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 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, the optional User Spreadsheet 
tool predicts the distance at which, if a marine mammal remained at 
that distance for the duration of the activity, it would be expected to 
incur PTS. Inputs used in the optional User Spreadsheet tool, and the 
resulting estimated isopleths, are reported below.

                                                            Table 6--User Spreadsheet Inputs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Vibratory                      Impact                        DTH
                                                                 ---------------------------------------------------------------------------------------
                                                                   30-inch steel   42-inch steel     30-inch       42-inch       30-inch       42-inch
                                                                       piles           piles       steel piles   steel piles   steel piles   steel piles
                                                                 ---------------------------------------------------------------------------------------
                                                                   Installation
                                                                    or removal     Installation   Installation  Installation  Installation  Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used                                              A.1) Vibratory  A.1) Vibratory   E.1) Impact   E.1) Impact      E.2) DTH      E.2) DTH
                                                                    Pile Driving    Pile Driving  Pile Driving  Pile Driving  Pile Driving  Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Level (SPL)                                                       166 RMS       168.2 RMS       177 SEL       179 SEL  174 RMS, 164  174 RMS, 164
                                                                                                                                       SEL           SEL
--------------------------------------------------------------------------------------------------------------------------------------------------------
Transmission Loss Coefficient...................................              15              15            15            15            15            15
Weighting Factor Adjustment (kHz)...............................             2.5             2.5             2             2             2             2
Activity Duration per day (minutes).............................              60             120           120           180           150           180
Strike Rate per second..........................................  ..............  ..............  ............  ............            10            10
Number of strikes per pile......................................  ..............  ..............           900         1,800  ............  ............
Number of piles per day.........................................               4               4             4             4             3             3
Distance of sound pressure level measurement....................              10              10            10            10            10            10
--------------------------------------------------------------------------------------------------------------------------------------------------------


   Table 7--Level A Harassment and Level B Harassment Isopleths From Vibratory and Impact Pile Driving and DTH
----------------------------------------------------------------------------------------------------------------
                                                    Level A harassment isopleths (m)                   Level B
                                   -----------------------------------------------------------------  harassment
             Pile type                                                                                 isopleth
                                         LF           MF           HF           PW           OW          (m)
----------------------------------------------------------------------------------------------------------------
                                                    Vibratory
----------------------------------------------------------------------------------------------------------------
42-inch steel pipe piles..........         32.7          2.9         48.4         19.9          1.4       16,343
30-inch Steel pipe piles..........         14.7          1.3         21.8          8.9          0.6       11,659
----------------------------------------------------------------------------------------------------------------
                                                       DTH
----------------------------------------------------------------------------------------------------------------
42-inch Steel pipe piles..........      2,549.4         90.7      3,036.7      1,364.3         99.3       39,811
30-inch Steel pipe piles..........      2,257.6         80.3      2,689.2      1,208.2         88.0       39,811
----------------------------------------------------------------------------------------------------------------
                                                     Impact
----------------------------------------------------------------------------------------------------------------
42-inch steel pipe piles..........      2,015.1         71.7      2,400.3      1,078.4         78.5        1,359
30-inch Steel pipe piles..........        933.8         33.2      1,112.3        499.7         36.4        1,166
----------------------------------------------------------------------------------------------------------------


[[Page 74468]]

Marine Mammal Occurrence and Take Estimation

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information which 
will inform the take calculations. We describe how the information 
provided is synthesized to produce a quantitative estimate of the take 
that is reasonably likely to occur and proposed for authorization.
    As described above, for some species (humpback whale, killer whale, 
Steller sea lion and harbor seal) observations within the project area 
from the prior monitoring were available to directly inform the take 
estimates, while for other species (fin whale, minke whale, sperm 
whale, Baird's beaked whale, Stejneger's beaked whale, Dall's porpoise, 
harbor porpoise and northern fur seal) they were not. Prior surveys 
include Protected Species Observer (PSO) monitoring completed at the 
project site on 60 days between June and August 2021 during the 
emergency fuel pier repair, island-wide faunal surveys completed by the 
USACE Engineer Research Development Center (ERDC) across 33 days 
between 2016 and 2019 (primarily in the spring and fall), and island-
wide marine mammal surveys completed by the USACE Civil Works 
Environmental Resource Section on 26 days between May and October 2021. 
From all three surveys, data that were collected within the project 
area are primarily the basis for the take estimates because those data 
best represents what might be encountered there. Average group sizes 
used to inform Level B take estimates (which also underlie the 
estimates for Level A harassment) for all species with prior 
observations in the project area are primarily based on those data. 
Alternate methods utilizing average group sizes informed primarily by 
Alaska's Wildlife Notebook Series are used for species without prior 
observations.
    Also of note, while the results are not significantly different, in 
some cases we recommended modified methods for estimating take from 
those presented by the applicant and have described them below. A 
summary of proposed take, including as a percentage of population for 
each of the species, is shown in table 8.

Fin Whale

    No fin whale were reported during monitoring conducted for the EAS 
fuel pier emergency repair completed in 2021, nor during other surveys 
completed from Shemya Island (see application). Accordingly, average 
group size, estimated group size based on information shared in the 
Alaska Wildlife Notebook Series (Clark 2008a), is used as the basis for 
the take estimates.
    USAF requested 17 takes of fin whales by Level B harassment, using 
a calculation based on of 0.002 groups of eight fin whales per hour of 
construction activity. NMFS concurs with USAF's predicted group size of 
fin whale (8 individuals), but since there are no observations of this 
species from Shemya Island, NMFS finds it more appropriate to estimate 
take by Level B harassment using a less granular occurrence estimate 
(monthly) rather than USAF's hourly occurrence estimate. Specifically, 
1 group of 8 fin whales is predicted every 2 construction months, based 
on the applicant's prediction that this species would be rare in the 
project area. The duration of the construction is 160 days (2.65 x the 
basic 60 day period) and 8 * 2.65 = 21 takes by Level B harassment).
    Although the shutdown zone is larger than the Level A harassment 
zone for low frequency cetaceans, USAF indicates that at >=2,000 m, it 
becomes more challenging to reliably detect low frequency cetaceans in 
some environmental conditions, and therefore it is possible that a fin 
whale could enter the Level A harassment zone during DTH activities and 
stay long enough to incur PTS before USAF detects the animal and shuts 
down. As such, USAF requested and NMFS proposed to authorize a small 
amount of take by Level A harassment of fin whales. NMFS calculated 
takes by Level A harassment by first determining the proportion of the 
area of largest Level A harassment zone (42-inch DTH, 2,549 m) that 
occurs beyond the readily observable 2,000 m from the pile driving 
location (i.e., 7.5 km\2\-5 km\2\/7.5 km\2\ = 0.33). This ratio was 
multiplied by the estimated fin whale exposures, which is generally one 
group of eight fin whale that would occur every 2 construction months 
(or 60 days, adjusted by 1.2 to account for the 70 days that DTH 
activities are planned). Multiplying these factors (8 * 1.2 * 0.33) 
results in = 3 takes by Level A harassment).
    Any individuals exposed to the higher levels associated with the 
potential for PTS closer to the source might also be behaviorally 
disturbed, however, for the purposes of quantifying take we do not 
count those exposures of one individual as both a Level A harassment 
take and a Level B harassment take, and therefore takes by Level B 
harassment calculated as described above are further modified to deduct 
the proposed amount of take by Level A harassment (i.e., 21-3 = 18).
    Therefore, NMFS proposes to authorize 3 takes by Level A harassment 
and 18 takes by Level B harassment for fin whales, for a total of 21 
takes.

Humpback Whale

    Across 119 days of marine mammal surveys completed from Shemya 
Island between 2016 and 2021, seven humpback whales were observed in 
the project area. The average group size for humpback whales detected 
in the project area was 2 humpback whales per group detected.
    For estimating take by Level B harassment where monitoring data 
confirmed the presence of the marine mammal species, NMFS concurred 
with USAF's proposed approach. USAF requested take by Level B 
harassment by predicting that 0.07 groups of humpback whales would be 
sighted every hour, which was based on the applicant predicting this 
species would commonly occur within the project area. This was then 
multiplied by the average group size for humpback whales (2 
individuals), to achieve an hourly humpback rate. Finally, these 
numbers are multiplied by the hours of construction activity. (0.07 * 2 
* 1,101 = 154 takes by Level B harassment).
    Although the shutdown zone is larger than the Level A harassment 
zone for low frequency cetaceans, USAF indicates that at >=2,000 m, it 
becomes more challenging to reliably detect low frequency cetaceans in 
some environmental conditions, and therefore it is possible that 
humpback whales could enter the Level A harassment zone during DTH 
activities and stay long enough to incur PTS before USAF detects the 
animal and shuts down. As such, USAF requested and NMFS proposed to 
authorize a small amount of take by Level A harassment of humpback 
whales. NMFS calculated takes by Level A harassment by determining the 
proportion of the area of largest Level A harassment zone (42-inch DTH, 
2,549 m) that occurs beyond 2,000 m from the pile driving location 
(i.e., 7.5 km\2\-5 km\2\/7.5 km\2\ = 0.33) and multiplying this ratio 
by the estimated humpback whale exposures (0.07 groups of 2 humpback 
whale) that would occur every construction hour that DTH activities are 
planned (624 hours) (0.07 * 2 * 624 * 0.33 = 29 takes by Level A 
harassment).
    For the reasons described above, takes by Level B harassment were 
modified to deduct the proposed amount of take by Level A harassment 
(i.e., 154-29 = 125).
    Therefore, NMFS proposes to authorize 29 takes by Level A 
harassment and 125 takes by Level B

[[Page 74469]]

harassment for humpback whales, for a total of 154 takes.

Minke Whale

    No minke whales were reported during monitoring conducted for the 
EAS fuel pier emergency repair completed in 2021, nor during other 
surveys completed from Shemya Island (e.g., see application). 
Accordingly, average group size, estimated based on group size 
information shared in the Alaska Wildlife Notebook Series (Clark 
2008a), is used as the basis for the take estimates (Guerrero 2008b).
    USAF requested 7 takes of minke whales by Level B harassment, using 
a calculation of of 0.002 groups of three minke whales per hour of 
construction activity. NMFS concurs with USAF's predicted group size of 
minke whale (three individuals), but since there are no observations of 
this species from Shemya Island, NMFS finds it more appropriate to 
estimate take by Level B harassment using a less granular occurrence 
estimate (monthly) rather than USAF's hourly occurrence estimate. 
Specifically, one group of three minke whales is predicted every 2 
construction months, based on the applicant's prediction that this 
species would be rare in the project area. The duration of construction 
is 160 days (2.65 * the basic 60 day period, which corresponds to two 
months) and 3 * 2.65 = 8 takes by Level B harassment.
    Although the shutdown zone is larger than the Level A harassment 
zone for low frequency cetaceans, USAF indicates that at >=2,000 m, it 
becomes more challenging to reliably detect low frequency cetaceans in 
some environmental conditions, and therefore it is possible that a 
minke whale could enter the Level A harassment zone during DTH 
activities and stay long enough to incur PTS before USAF detects the 
animal and shuts down. As such, USAF requested and NMFS proposed to 
authorize a small amount of take by Level A harassment of minke whales. 
NMFS calculated takes by Level A harassment by determining the 
proportion of the area of largest Level A harassment zone (42-inch DTH, 
2,549 m) that occurs beyond the readily observable 2,000 m from the 
pile driving location (i.e., 7.5 km\2\-5 km\2\/7.5 km\2\ = 0.33). This 
ratio was multiplied by the estimated minke whale exposures, which is 
generally one group of three minke whales every 2 construction months 
(or 60 days), adjusted by 1.2 to account for the 70 days that DTH 
activities are planned. Multiplying these factors 1.2 * 0.33 results in 
1 take by Level A harassment. Since the predicted average group size of 
minke whale is three, NMFS proposes to authorize three takes by Level A 
harassment of minke whale.
    For reasons described above, takes by Level B harassment were 
modified to deduct the proposed amount of take by Level A harassment 
(i.e., 8-3 = 5).
    Therefore, NMFS proposes to authorize three takes by Level A 
harassment and five takes by Level B harassment for minke whales, for a 
total of eight takes.

Sperm Whale

    Across 119 monitoring days between 2016 and 2021, four sperm whales 
were observed on a single day from Shemya Island, though outside of the 
project area (see application).
    USAF requested 27 takes of sperm whale by Level B harassment, using 
a calculation based on of 0.006 groups of four sperm whales per hour of 
construction activity. NMFS concurs with USAF's predicted group size of 
sperm whale (4 individuals, which corresponds to the number of sperm 
whales detected on a single day during Shemya Island marine mammal 
surveys), but since there are few observations of this species from 
Shemya Island, NMFS finds it more appropriate to estimate take by Level 
B harassment using a less granular occurrence estimate (monthly) rather 
than USAF's hourly occurrence estimate. Specifically, two groups of 
four sperm whales is predicted every 1 construction month based on 
sperm whales being one of the most frequently sighted marine mammals in 
the high latitude regions of the North Pacific, including the Bering 
Sea and the Aleutian Islands. The duration of the construction is 5 
months and 2 * 4 * 5 = 40 takes by Level B harassment.
    Due to the small Level A harassment zones (table 9), which do not 
reach deep water where sperm whales are expected to be encountered, 
coupled with the implementation of shutdown zones, which will be larger 
than Level A harassment zones for mid-frequency cetaceans (described in 
the Proposed Mitigation section), NMFS concurs with USAF's assessment 
that take by Level A harassment is not anticipated for sperm whale. 
Therefore, NMFS proposed to authorize all 40 estimated exposures as 
takes by Level B harassment. Takes by Level A harassment for sperm 
whales are not requested nor are they proposed for authorization.

Baird's Beaked Whale

    Baird's beaked whales are usually found in tight social groups 
(schools or pods) averaging between 5 and 20 individuals, but they have 
occasionally been observed in larger groups of up to 50 animals. Across 
119 days of marine mammal surveys completed from Shemya Island between 
2016 and 2021, no observations of Baird's beaked whale were recorded 
(see application). Accordingly, average group size, estimated based on 
group size information shared in the Alaska Wildlife Notebook Series 
(Guerrero 2008a), is used as the basis for take estimates.
    USAF requested 11 takes by Level B harassment, using a calculation 
based on 0.001 groups of ten Baird's beaked whales per hour of 
construction activity. NMFS concurs with USAF's predicted group size of 
Baird's beaked whale (10 individuals), but since there are no 
observations of this species from Shemya Island, NMFS finds it more 
appropriate to estimate take by Level B harassment using a less 
granular occurrence estimate (monthly) rather than USAF's hourly 
occurrence estimate. Specifically, 1 group of 10 Baird's beaked whales 
is predicted across the project, which is based on this species being 
shy and preferring deep waters and as such the applicant predicted they 
would be very rare in the project area. Therefore, NMFS proposes to 
authorize 10 takes of Baird's beaked whale by Level B harassment.
    Due to the small Level A harassment zones (table 9), which do not 
reach deep water where Baird's beaked whales are expected to be 
encountered, coupled with the implementation of shutdown zones, which 
will be larger than Level A harassment zones for mid-frequency 
cetaceans (described in the Proposed Mitigation section), NMFS concurs 
with USAF's assessment that take by Level A harassment is not 
anticipated for Baird's beaked whale. Therefore, NMFS proposed to 
authorize all 10 estimated exposures as takes by Level B harassment. 
Takes by Level A harassment for Baird's beaked whales are not requested 
nor are they proposed for authorization.

Stejneger's Beaked Whale

    Across 119 days of marine mammal surveys completed from Shemya 
Island between 2016 and 2021, no observations of Stejneger's beaked 
whale were recorded (see application). Accordingly, average group size, 
estimated based on group size information shared in the Alaska Wildlife 
Notebook Series (Guerrero 2008a), is used as the basis for take 
estimates.
    USAF requested 9 takes of Stejneger's beaked whale by Level B 
harassment, using a calculation based on of 0.001 groups of eight 
Stejneger's beaked whales per hour of construction activity.

[[Page 74470]]

NMFS concurs with USAF's predicted group size of Stejneger's beaked 
whale (eight individuals), but since there are no observations of this 
species from Shemya Island, NMFS finds it more appropriate to estimate 
take by Level B harassment using a less granular occurrence estimate 
(monthly) rather than USAF's hourly occurrence estimate. Specifically, 
one group of eight Stejneger's beaked whales is predicted across the 
entirety of the project, based on this species being shy and preferring 
deep waters and as such the applicant predicted they would only be very 
rarely encountered in the project area. Therefore NMFS proposes to 
authorize 8 Stejneger's beaked whale by level B harassment.
    Due to the small Level A harassment zones (table 9), which do not 
reach deep water where Stejneger's beaked whales are expected to be 
encountered, coupled with the implementation of shutdown zones, which 
will be larger than Level A harassment zones for mid-frequency 
cetaceans (described in the Proposed Mitigation section), NMFS concurs 
with USAF's assessment that take by Level A harassment is not 
anticipated for Stejneger's beaked whale. Therefore, NMFS proposed to 
authorize all eight estimated exposures as takes by Level B harassment. 
Takes by Level A harassment for Stejneger's beaked whales are not 
requested nor are they proposed for authorization.

Killer Whale

    Across 119 days of marine mammal surveys completed from Shemya 
Island between 2016 and 2021, 69 killer whales were observed in the 
project area. The average group size for killer whales detected in the 
project area was 8 killer whales per group detected.
    For estimating take by Level B harassment where monitoring data 
confirmed the presence of the marine mammal species, NMFS concurred 
with USAF's proposed approach. USAF requested take by Level B 
harassment by predicting that 0.02 groups of killer whales would be 
sighted every hour, which was based on the applicant's prediction that 
this species would commonly be encountered in the project area. This 
was then multiplied by the average group size for humpback whales (8 
individuals), to achieve an hourly killer whale rate. Finally, these 
numbers are multiplied by the hours of construction activity. (0.02 * 8 
* 1,101 = 176 takes by Level B harassment).
    Due to the small Level A harassment zones (table 9), coupled with 
the implementation of shutdown zones, which will be larger than Level A 
harassment zones for mid-frequency cetaceans (described in the Proposed 
Mitigation section), NMFS concurs with USAF's assessment that take by 
Level A harassment is not anticipated for killer whale. Therefore, NMFS 
proposed to authorize all 176 estimated exposures as takes by Level B 
harassment. Takes by Level A harassment for killer whale are not 
requested nor are they proposed for authorization.

Dall's Porpoise

    No Dall's porpoise were reported during monitoring conducted for 
the EAS fuel pier emergency repair completed in 2021, nor during other 
surveys completed from Shemya Island (see application). Dall's porpoise 
generally travel in groups of 10 to 20 individuals but can occur in 
groups with over hundreds of individuals (Wells, 2008). Accordingly, 
average group size, estimated based group size information shared in 
the Alaska Wildlife Notebook Series (Wells 2008), is used as the basis 
for the take estimates, is used as the basis for take estimates.
    USAF requested 33 takes of Dall's porpoise by Level B harassment, 
using a calculation based on of 0.002 groups of 15 Dall's porpoise per 
hour of construction activity. NMFS concurs with USAF's predicted group 
size of Dall's porpoise (15 individuals), but since there are no 
observations of this species from Shemya Island, NMFS finds it more 
appropriate to estimate take by Level B harassment using a less 
granular occurrence estimate (monthly) rather than USAF's hourly 
occurrence estimate. Specifically, 1 group of 15 Dall's porpoise is 
predicted every 2 construction months, based on the applicant's 
prediction that this species would be rarely encountered in the project 
area. The duration of the construction is 160 days (2.65 * the basic 60 
day period that corresponds to two construction months) and 15 * 2.65 = 
40 takes by Level B harassment.
    For most activities, NMFS calculated takes by Level A harassment by 
determining the ratio of the largest Level A harassment area for 42-
inch DTH activities (i.e., 10.2 km\2\ for a Level A harassment distance 
of 3,037 m) minus the area of the proposed shutdown zone for Dall's 
porpoise (i.e., 0.5 km\2\ for a shutdown zone distance of 500 m) to the 
area of the Level B harassment isopleth (1,285.9 km\2\) for a Level B 
harassment distance of 39,811 m (i.e., (10.2 km\2\-0.5 km\2\)/1,285.9 
km\2\ = 0.008). We then multiplied this ratio by the number of 
estimated Dall's porpoise exposures calculated as described above for 
Level B harassment to determine take by Level A harassment (i.e., 0.008 
* 40 exposures = 0.32 takes by Level A harassment).
    For Level A harassment during impact pile driving of 42-inch piles, 
for which the Level A harassment zone is larger than the Level B 
harassment zone, NMFS estimates take based on 1 group of 15 Dall's 
porpoise every 2 months, or 60 days, in consideration of the 52 days 
(0.87 of 60) of impact driving of 42-in piles (15 Dall's porpoise * 
0.87 months = 13.05) for a total of 13.37 takes by Level A harassment 
(0.32 + 13.05 = 13).
    For reasons described above, takes by Level B harassment were 
modified to deduct the proposed amount of take by Level A harassment 
(i.e., 40-13 = 27).
    Therefore, NMFS proposes to authorize 13 takes by Level A 
harassment and 27 takes by Level B harassment for Dall's porpoise, for 
a total of 40 takes.

Harbor Porpoise

    Across 119 monitoring days between 2016 and 2021, one group of two 
to three harbor porpoise were observed from Shemya Island (see 
application), though outside of the project area. Average group size, 
estimated based on the Alaska Wildlife Notebook Series (Schmale 2008), 
is used as the basis for take estimates.
    USAF requested 11 takes of harbor porpoise by Level B harassment, 
using a calculation based on of 0.01 groups of one harbor porpoise per 
hour of construction activity. NMFS concurs with USAF's predicted group 
size of harbor porpoise (1 individual), but since there are few 
observations of this species from Shemya Island, NMFS finds it more 
appropriate to estimate take by Level B harassment using a less 
granular occurrence estimate (monthly) rather than USAF's hourly 
occurrence estimate. Specifically, 3 groups of 1 harbor porpoise is 
predicted every 1 construction month. The duration of construction is 5 
months and 3 * 5 = 15 takes by Level B harassment.
    For most activities, NMFS calculated takes by Level A harassment by 
determining the ratio of the largest Level A harassment area for 42-
inch DTH activities (i.e., 10.2 km\2\ for a Level A harassment distance 
of 3,037 m) minus the area of the proposed shutdown zone for harbor 
porpoise (i.e., 0.5 km\2\ for a shutdown zone distance of 500 m) to the 
area of the Level B harassment isopleth (1,285.9 km\2\) for a Level B 
harassment distance of 39,811 m (i.e., (10.2 km\2\-0.5 km\2\)/1,285.9 
km\2\ = 0.008). We then multiplied this ratio by the number of 
estimated harbor porpoise exposures calculated as described above for 
Level B harassment to determine take by Level

[[Page 74471]]

A harassment (i.e., 0.008 * 15 exposures = 0.12 takes by Level A 
harassment).
    For Level A harassment during impact pile driving of 42-inch piles, 
for which the Level A harassment zone is larger than the Level B 
harassment zone, NMFS estimates take based on 3 groups of 1 harbor 
porpoise could be taken by Level A harassment every 1 month, or 30 days 
in consideration of the 52 days (1.7 * 30) of impact pile driving of 
42-inch piles (3 groups of1 harbor porpoise * 1.7 = 5.1) for a total of 
five takes by Level A harassment (0.12 + 5.1 = 5).
    For reasons described above, takes by Level B harassment were 
modified to deduct the proposed amount of take by Level A harassment 
(i.e., 15-5 = 10).
    Therefore, NMFS proposes to authorize 5 takes by Level A harassment 
and 10 takes by Level B harassment for harbor porpoise, for a total of 
15 takes.

Northern Fur Seal

    USAF requested 33 takes of northern fur seal by Level B harassment 
using a calculation based on 0.003 groups of eight northern fur seals 
per hour of construction activity. NMFS disagrees with USAF's predicted 
group size of northern fur seal, as these animals are typically 
solitary when at sea. Additionally, because there are no records of 
northern fur seal in the area, NMFS finds it more appropriate to 
estimate take by Level B harassment according to a less granular 
occurrence estimate (monthly) rather than USAF's hourly occurrence 
estimate. Specifically, one group of one northern fur seal every 1 
construction month is predicted and 1 * 5 = 5 takes by Level B 
harassment.
    Due to the small Level A harassment zones (table 9), coupled with 
the implementation of shutdown zones, which will be larger than Level A 
harassment zones for otariids (described in the Proposed Mitigation 
section), NMFS concurs with USAF's assessment that take by Level A 
harassment is not anticipated for northern fur seal. Therefore, NMFS 
proposed to authorize all five estimated exposures as takes by Level B 
harassment. Takes by Level A harassment for northern fur seals are not 
requested nor are they proposed for authorization.

Steller Sea Lion

    Steller sea lions are frequently observed around Shemya Island 
outside of the ensonified area, but only occasionally observed in Alcan 
Harbor and Shemya Pass (see application). Across 119 monitoring days 
between 2016 and 2021, 16 Steller sea lions were observed within the 
project area. The average group size for Steller sea lion detected in 
the project area as well as around Shemya Island was 1 Steller sea lion 
per detection.
    For estimating take by Level B harassment where monitoring data 
confirmed the presence of the marine mammal species, NMFS concurred 
with USAF's proposed approach. USAF requested take by Level B 
harassment by predicting that 0.09 groups of Steller sea lion would be 
sighted every hour, which was based on the applicant's prediction that 
this species would be more commonly encountered in the project area. 
This was then multiplied by the average group size for Steller sea lion 
(1 individual), to achieve an hourly steller sea lion rate. Finally, 
these numbers are multiplied by the hours of construction activity. 
(0.09 * 1 * 1,101 = 99 takes by Level B harassment).
    Due to the small Level A harassment zones (table 9), coupled with 
the implementation of shutdown zones, which will be larger than Level A 
harassment zones for otariids (described in the Proposed Mitigation 
section), NMFS concurs with USAF's assessment that take by Level A 
harassment is not anticipated for Steller sea lion. Therefore, NMFS 
proposed to authorize all 99 estimated exposures as takes by Level B 
harassment. Takes by Level A harassment for Steller sea lion are not 
requested nor are they proposed for authorization.

Harbor Seal

    Across 119 monitoring days between 2016 and 2021, 54 harbor seals 
were observed within the project area. The average group size for 
harbor seals detected in the project area was 1 harbor seals per group.
    For estimating take by Level B harassment where monitoring data 
confirmed the presence of the marine mammal species, NMFS concurred 
with USAF's proposed approach. USAF requested take by Level B 
harassment by predicting that 0.14 groups of harbor seals would be 
sighted every hour, which was based on the fact that this species is 
expected to more commonly occur within the project area. This was then 
multiplied by the average group size for harbor seal (1 individual), to 
achieve an hourly harbor seal rate. Finally, these numbers are 
multiplied by the hours of construction activity. (0.14 * 1 * 1,101 = 
154 takes by Level B harassment).
    NMFS initially calculated takes by Level A harassment by 
determining the ratio of the largest Level A harassment area for 42-
inch DTH activities (i.e., 2.6 km\2\ for a Level A harassment distance 
of 1364 m) minus the area of the proposed shutdown zone for harbor seal 
(i.e., 0.37 km\2\ for a shutdown zone distance of 400 m) to the area of 
the Level B harassment isopleth (1,285.9 km\2\) for a Level B 
harassment distance of 39,811 m (i.e., (2.6 km\2\-0.37 km\2\)/1,285.9 
km\2\ = 0.002). We then multiplied this ratio by the number of 
estimated harbor seal exposures calculated as described above for Level 
B harassment to determine take by Level A harassment (i.e., 0.002 * 154 
exposures = 0.3 takes by Level A harassment).
    Because harbor seals typically inhabit areas closer to shore rather 
than distances represented by the largest level B zone (39,811 m), NMFS 
determined that the method above could underestimate potential take by 
Level A harassment. NMFS accordingly estimated additional takes by 
Level A harassment by determining the ratio of harbor seals that were 
observed beyond the proposed shutdown zone isopleth compared to the 
harbor seals that were observed closer to construction activities 
during the EAS fuel pier emergency repair that was completed in 2021 
(i.e., 11/38 = 0.29 harbor seals). We then multiplied this ratio by the 
total number of estimated harbor seal exposures to determine take by 
Level A harassment (i.e., 0.29 * 154 exposures = 45) for a total of 45 
takes by Level A harassment (0.3 + 45 = 45.3).
    For reasons described above, takes by Level B harassment were 
modified to deduct the proposed amount of take by Level A harassment 
(i.e., 154-45 = 109).
    Therefore, NMFS proposes to authorize 45 takes by Level A 
harassment and 109 takes by Level B harassment for harbor seal, for a 
total of 154 takes.

[[Page 74472]]



           Table 8--Proposed Take by Stock and Harassment Type and as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
                                                                     Proposed authorized take      Proposed take
                                                                 --------------------------------      as a
                Species                           Stock                                            percentage of
                                                                      Level B         Level A          stock
                                                                    harassment      harassment       abundance
----------------------------------------------------------------------------------------------------------------
Fin Whale.............................  Northeast Pacific.......              18               3              >1
Humpback Whale........................  Western North Pacific...               3               1              >1
                                        Mexico--North Pacific...               9               2             1.2
Hawai[revaps]i........................  113.....................              26             1.2
Minke Whale...........................  Alaska..................               5               3              >1
Sperm Whale...........................  North Pacific...........              40               0            16.4
Baird's beaked whale..................  Alaska..................              10               0              -*
Stejneger's beaked whale..............  Alaska..................               8               0              -*
Killer whale..........................  ENP Alaska Resident                  176               0             9.2
                                         Stock.
                                        ENP Gulf of Alaska,                                                   30
                                         Aleutian Islands, and
                                         Bering Seal.
Dall's Porpoise.......................  Alaska..................              26              13              <1
Harbor Porpoise.......................  Bering Seal.............              10               5              <1
Northern Fur Seal.....................  Eastern Pacific.........               5               0              <1
Steller Sea Lion......................  Western, U.S............              99               0              <1
Harbor Seal...........................  Aleutian Islands........             109              45             2.8
----------------------------------------------------------------------------------------------------------------
* Reliable abundance estimates for these stock are currently unavailable.

Proposed Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting the 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks, and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, NMFS 
considers two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is 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.
    USAF must ensure that construction supervisors and crews, the 
monitoring team and relevant USAF staff are trained prior to the start 
of all pile driving and DTH activity, so that responsibilities, 
communication procedures, monitoring protocols, and operational 
procedures are clearly understood. New personnel joining during the 
project must be trained prior to commencing work.

Mitigation for Marine Mammals and Their Habitat

    Shutdown Zones--For all pile driving/removal and DTH activities, 
USAF would 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 
9). In most cases, the shutdown zones are based on the estimated Level 
A harassment isopleth distances for each hearing group, as requested by 
USAF. However, in cases where it would be challenging to detect marine 
mammals at the Level A isopleth, (e.g., for high frequency cetaceans 
and phocids during DTH activities and impact pile driving), smaller 
shutdown zones have been proposed (table 9). Additionally, USAF has 
agreed to implement a minimum shutdown zone of 25 m during all pile 
driving and removal activities and DTH.
    Finally, construction supervisors and crews, PSOs, and relevant 
USAF staff must avoid direct physical interaction with marine mammals 
during construction activity. If a marine mammal comes within 10 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 shutdown zone 
indicated in table 9 or 15 minutes have passed for delphinids or 
pinnipeds or 30 minutes for all other species without re-detection of 
the animal.
    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 the harassment zone.

[[Page 74473]]



                                        Table 9--Proposed Shutdown Zones
----------------------------------------------------------------------------------------------------------------
                                                                            Shutdown zones (m)
             Activity                  Pile diameter    --------------------------------------------------------
                                                              LF          MF         HF         PW         OW
----------------------------------------------------------------------------------------------------------------
Vibratory Installation or Removal  42-in...............                             50
                                   30-in...............                             25
                                                        --------------------------------------------------------
DTH..............................  42-in...............        2,600        100        500        400        100
                                   30-in...............        2,300         80                               90
Impact Pile......................  42-in...............        2,100                                          80
                                   30-in...............        1,000         50                               50
----------------------------------------------------------------------------------------------------------------

    Protected Species Observers--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. USAF would employ at least two PSOs for all pile 
driving and DTH activities.
    Monitoring for 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 the Level B 
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 will observe the shutdown, Level A 
harassment, and Level B harassment 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 15 minutes have passed for delphinids or pinnipeds or 30 minutes 
have passed for all other species without re-detection of the animal. 
If a marine mammal for which Level B harassment take is authorized is 
present in the Level B harassment zone, activities would begin and 
Level B harassment take would be recorded.
    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 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 and removal activities.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means of 
effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present while 
conducting the activities. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
    <bullet> Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
    <bullet> Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
    <bullet> Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
    <bullet> How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
    <bullet> Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
    <bullet> Mitigation and monitoring effectiveness.
    Visual Monitoring--Marine mammal monitoring must be conducted in 
accordance with the Marine Mammal Monitoring and Mitigation Plan. 
Marine mammal monitoring during pile driving and removal and DTH 
activities must be conducted by NMFS-approved PSOs in a manner 
consistent with the following:
    <bullet> PSOs must be independent of the activity contractor (for 
example, employed by a subcontractor), and have no other assigned tasks 
during monitoring periods;

[[Page 74474]]

    <bullet> 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;
    <bullet> 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 a NMFS-issued incidental take authorization.
    <bullet> 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,
    <bullet> PSOs must be approved by NMFS prior to beginning any 
activity subject to this IHA.
    PSOs must also have the following additional qualifications:
    <bullet> Ability to conduct field observations and collect data 
according to assigned protocols;
    <bullet> Experience or training in the field identification of 
marine mammals, including identification of behaviors;
    <bullet> Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    <bullet> Writing skills sufficient to prepare a report of 
observations including, but not limited to, the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was note implemented when required); 
and marine mammal behavior; and
    <bullet> Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    Visual monitoring will be conducted by a minimum of two trained 
PSOs positioned at suitable vantage points. One PSO will have an 
unobstructed view of all water within the shutdown zone and will be 
stationed at or near the pier. Remaining PSOs will be placed at one or 
more of the observer monitoring locations identified on Figure 3-3 of 
the marine mammal monitoring and mitigation plan, in order to observe 
as much as the Level A and Level B harassment zone as possible. All 
PSOs will have access to 20 by 60 spotting scope on a window mount or 
tripod.
    Monitoring will 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

    USAF will 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:
    <bullet> Dates and times (begin and end) of all marine mammal 
monitoring;
    <bullet> 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, vibratory, DTH); (2) Total 
duration of driving time for each pile (vibratory driving) and number 
of strikes for each pile (impact driving); and (3) For DTH drilling, 
duration of operation for both impulsive and non-pulse components;
    <bullet> PSO locations during marine mammal monitoring;
    <bullet> Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
    <bullet> Upon observation of a marine mammal, the following 
information: (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);
    <bullet> Number of marine mammals detected within the harassment 
zones, by species; and,
    <bullet> 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 
datasheets and/or raw sighting data 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 Office of Protected Resources (OPR), NMFS 
(<a href="/cdn-cgi/l/email-protection#164644385f4246385b79787f6279647f787144736679646265567879777738717960"><span class="__cf_email__" data-cfemail="762624583f2226583b19181f0219041f181124130619040205361819171758111900">[email protected]</span></a> and <a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="a3cad7d38dc5cfc6cecacdc4e3cdccc2c28dc4ccd5">[email protected]</a>) and to the 
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:
    <bullet> Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
    <bullet> Species identification (if known) or description of the 
animal(s) involved;
    <bullet> Condition of the animal(s) (including carcass condition if 
the animal is dead);
    <bullet> Observed behaviors of the animal(s), if alive;
    <bullet> If available, photographs or video footage of the 
animal(s); and
    <bullet> General circumstances under which the animal was 
discovered.

[[Page 74475]]

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 2, given that many of the anticipated 
effects of this project on different marine mammal stocks are expected 
to be relatively similar in nature. Where there are meaningful 
differences 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 and DTH activities associated with the EAS fuel pier 
repair 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 DTH. Potential takes could occur if marine mammals are present in 
zones ensonified above the thresholds for Level B harassment or Level A 
harassment, identified above, while activities are underway.
    No serious injury or mortality would be expected, even in the 
absence of required mitigation measures, given the nature of the 
activities. Further, no take by Level A harassment is anticipated for 
otariids and mid-frequency cetaceans, due to the application of 
proposed mitigation measures, such as shutdown zones that encompass 
Level A harassment zones for these species. The potential for 
harassment would be minimized through the implementation of planned 
mitigation measures (see Proposed Mitigation section).
    Take by Level A harassment is proposed for six species (harbor 
porpoise, Dall's porpoise, harbor seal, fin whale, humpback whale, and 
minke whale) as the Level A harassment zone exceeds the size of the 
shutdown zones (high frequency cetaceans and phocids), or, in the case 
of low frequency cetaceans, the shutdown zone is so large that it is 
possible that a minke whale, fin whale, or humpback whale could enter 
the Level A harassment zone and remain within the zone for a duration 
long enough to incur PTS before being detected.
    Any take by Level A harassment is expected to arise from, at most, 
a small degree of PTS (i.e., minor degradation of hearing capabilities 
within regions of hearing that align most completely with the energy 
produced by impact pile driving such as the low-frequency region below 
2 kHz), not severe hearing impairment or impairment within the ranges 
of greatest hearing sensitivity. Animals 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.
    Given the small degree anticipated, any PTS potential incurred 
would not be expected to affect the reproductive success or survival of 
any individuals, much less result in adverse impacts on the species or 
stock.
    Additionally, some subset of the individuals that are behaviorally 
harassed could also simultaneously incur some small degree of TTS for a 
short duration of time. However, since the hearing sensitivity of 
individuals that incur TTS is expected to recover completely within 
minutes to hours, it is unlikely that the brief hearing impairment 
would affect the individual's long-term ability to forage and 
communicate with conspecifics, and would therefore not likely impact 
reproduction or survival of any individual marine mammal, let alone 
adversely affect rates of recruitment or survival of the species or 
stock.
    As described above, NMFS expects that marine mammals would likely 
move away from an aversive stimulus, especially at levels that would be 
expected to result in PTS, given sufficient notice through use of soft 
start. USAF would also shut down pile driving activities if marine 
mammals enter the shutdown zones (table 9) further minimizing the 
likelihood and degree of PTS that would be incurred.
    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 area does overlap a BIA identified as important for 
feeding by sperm whale (Brower et al., 2022). The BIA that overlaps the 
project area is active April through September, which overlaps USAF's 
proposed work period (April to October). White the BIA is considered to 
be of higher importance, the area of the BIA is very large, spanning 
the island chain, and the project area is very small in comparison. 
Further sperm whales utilize deeper waters to feed, and while the Level 
B harassment zone does extend into deeper waters, the sound levels at 
the distances that overlay deeper water where sperm whales might be 
foraging would be of comparatively lower levels. Given the extensive 
options for high quality foraging area near and outside of the project 
area, any impacts to feeding sperm whales would not be expected to

[[Page 74476]]

impact the survival or reproductive success of any individuals.
    The ensonfied area also overlaps ESA-designated critical habitat 
for western DPS Steller sea lion. Specifically, the Level B ensonified 
area overlaps with the aquatic zones of three designated major haulouts 
to the east and northwest of the project site: Shemya Island Major 
Haulout, Alaid Island Major Haulout, Attu/Chirikof Point Major Haulout. 
The ensonified area Level B harassment zone related to implementation 
of the proposed project, described in the Estimated Take of Marine 
Mammals section, overlaps with the designated aquatic zone of all three 
designated major haulouts. No terrestrial or in-air critical habitat of 
any major haulout overlaps with the project area. No Steller sea lions 
have been observed on Shemya Island Major Haulout during the most 
recent surveys (between 2015 and 2017) and only one Steller sea lion 
was observed at Attu/Chirikof Point Major Haulout. An average of 68 
non-pups and 7 pups were observed annually during this time at Alaid 
Island Major Haulout, which is 5 nmi northwest of the project site. The 
construction site itself does not overlap with critical habitat.
    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 some fish to leave the area of 
disturbance, thus temporarily impacting marine mammals' foraging 
opportunities in a limited portion of the foraging range. We do not 
expect pile driving activities to have significant consequences to 
marine invertebrate populations. Given the short duration of the 
activities and the relatively small area of the habitat that may be 
affected, the impacts to marine mammal habitat, including fish and 
invertebrates, are not expected to cause significant or long-term 
negative consequences.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect any of the species 
or stocks through effects on annual rates of recruitment or survival:
    <bullet> No serious injury or mortality is anticipated or 
authorized;
    <bullet> No Level A harassment of six species is proposed;
    <bullet> Level A harassment takes of six species proposed for 
authorization are expected to be of a small degree;
    <bullet> While impacts would occur within areas that are important 
for feeding for sperm whale, because of the small footprint of the 
activity relative to the area of these important use areas, we do not 
expect impacts to the reproduction and survival of any individuals;
    <bullet> Effects on species that serve as prey for marine mammals 
from the activities are expected to be short-term and, therefore, any 
associated impacts on marine mammal feeding are not expected to result 
in significant or long-term consequences for individuals, or to accrue 
to adverse impacts on their populations;
    <bullet> The lack of anticipated significant or long-term negative 
effects to marine mammal habitat; and
    <bullet> The efficacy of the mitigation measures in reducing the 
effects of the specified activities on all species and stocks.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted previously, only take of small numbers of marine mammals 
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is fewer than one-third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    The instances of take NMFS proposes to authorize are below one-
third of the estimated stock abundance for all stocks (table 8). The 
number of animals that we expect to authorize to be taken from these 
stocks would be considered small relative to the relevant stocks' 
abundances even if each estimated taking occurred to a new individual, 
which is an unlikely scenario.
    The best available abundance estimate for fin whale is not 
considered representative of the entire stock as surveys were limited 
to a small portion of the stock's range, but there are known to be over 
2,500 fin whales in the northeast Pacific stock (Muto et al., 2021). As 
such, the 18 takes by Level B harassment and 3 takes by Level A 
harassment proposed for authorization, compared to the abundance 
estimate, shows that less than 1 percent of the stock would be expected 
to be impacted.
    The most recent abundance estimate for the Mexico-North Pacific 
stock of humpback whale is likely unreliable as it is more than 8 years 
old. The most relevant estimate of this stock's abundance in the Bering 
Sea and Aleutian Islands is 918 humpback whales (Wade, 2021), so the 9 
proposed takes by Level B harassment and 2 proposed takes by Level A 
harassment, is small relative to the estimated abundance (1.2 percent), 
even if each proposed take occurred to a new individual.
    A lack of an accepted stock abundance value for the Alaska stock of 
minke whale did not allow for the calculation of an expected percentage 
of the population that would be affected. The most relevant estimate of 
partial stock abundance is 1,233 minke whales in coastal waters of the 
Alaska Peninsula and Aleutian Islands (Zerbini et al., 2006), so the 5 
proposed takes by Level B harassment, and 3 proposed takes by Level A 
harassment, compared to the abundance estimate, shows that less than 1 
percent of the stock would be expected to be impacted.
    The most recent abundance estimate for sperm whale in the North 
Pacific is likely unreliable as it is more than 8 years old and was 
derived from data collected in a small area that may not have included 
females and juveniles, and did not account for animals missed on the 
trackline. The minimum population estimate for this stock is 244 sperm 
whales, so the 40 proposed takes by Level B harassment is small 
relative to the estimated survey abundance, even if each proposed take 
occurred to a new individual.
    There is no abundance information available for any Alaskan stock 
of beaked whale. However, the take numbers are sufficiently small (8 
and 10 takes by Level B harassment for Stejneger's beaked whale and 
Baird's beaked whale, respectively) that we can safely assume that they 
are small relative to any reasonable assumption of likely population 
abundance for these stocks. For reference, current abundance estimates 
for other beaked whale stocks in the Pacific include 1,363 Baird's 
beaked whales (California, Oregon/Washington stock), 3,044 Mesoplodont 
beaked whales (CA/OR/WA stock),

[[Page 74477]]

5,454 Cuvier's beaked whales (CA/OR/WA stock), 564 Blainville's beaked 
whales (Hawai'i Pelagic stock), 2,550 Longman's beaked whales 
(Hawai[revaps]i stock), and 3,180 Cuvier's beaked whales (Hawai'i 
Pelagic stock).
    The Alaska stock of Dall's porpoise has no official NMFS abundance 
estimate for this area, as the most recent estimate is greater than 8 
years old. The most recent estimate was 13,110 animals for just a 
portion of the stock's range. Therefore, the 26 takes by Level B 
harassment and 13 takes by Level A harassment of this stock proposed 
for authorization, compared to the abundance estimate, shows that less 
than 1 percent of the stock would be expected to be impacted.
    For the Bering Sea stock of harbor porpoise, the most reliable 
abundance estimate is 5,713, a corrected estimate from a 2008 survey. 
However, this survey covered only a small portion of the stock's range, 
and therefore, is considered to be an underestimate for the entire 
stock (Muto et al., 2022). Given the proposed 10 takes by Level B 
harassment for the stock, and 5 takes by Level A harassment for the 
stock, compared to the abundance estimate, which is only a portion of 
the Bering Sea Stock, shows that, at most, less than 1 percent of the 
stock would be expected to be impacted.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals would be taken relative to the population 
size of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity: (1) 
that is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by, (i) causing 
the marine mammals to abandon or avoid hunting areas, (ii) directly 
displacing subsistence users, or (iii) placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) that 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    No subsistence hunting occurs on Shemya Island, which is a USAF Air 
Station; Access to the island is only provided by military aircraft and 
USAF-contracted charter planes for crews and workers. The nearest 
community that engages in subsistence hunting is located on Adak, 
Alaska which is 640 km (399 mi) to the east. Historically, an Alaska 
Native community on Attu, 60 km (37 mi) to the west, hunted for 
subsistence, but that community was destroyed during WWII and the 
residents that survived internment did not return to the island.
    Based on the description of the specified activity, NMFS has 
preliminarily determined that there will not be an unmitigable adverse 
impact on subsistence uses from USAF's proposed activities.

Endangered Species Act

    Section 7(a)(2) of the ESA (16 U.S.C. 1531 et seq.) requires that 
each Federal agency insure that any action it authorizes, funds, or 
carries out is not likely to jeopardize the continued existence of any 
endangered or threatened species or result in the destruction or 
adverse modification of designated critical habitat. To ensure ESA 
compliance for the issuance of IHAs, NMFS consults internally whenever 
we propose to authorize take for endangered or threatened species, in 
this case with the Alaska Regional Office.
    NMFS is proposing to authorize take of western DPS Steller sea 
lion, fin whale (northeast Pacific), and humpback whale (Mexico--North 
Pacific and western North Pacific), and sperm whale (North Pacific) 
which are listed under the ESA. The Permits and Conservation Division 
has requested initiation of section 7 consultation with the Alaska 
Regional Office for the issuance of this IHA. NMFS will conclude the 
ESA consultation prior to reaching a determination regarding the 
proposed issuance of the authorization.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to USAF for conducting the EAS Fuel Pier Replacement 
project in Alcan Harbor on Shemya Island, Alaska during April through 
October 2024, provided the previously mentioned mitigation, monitoring, 
and reporting requirements are incorporated. A draft of the proposed 
IHA can be found at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this notice of proposed IHA for the proposed 
construction project. We also request comment on the potential renewal 
of this proposed IHA as described in the paragraph below. Please 
include with your comments any supporting data or literature citations 
to help inform decisions on the request for this IHA or a subsequent 
renewal IHA.
    On a case-by-case basis, NMFS may issue a one-time, 1-year renewal 
IHA following notice to the public providing an additional 15 days for 
public comments when (1) up to another year of identical or nearly 
identical activities as described in the Description of Proposed 
Activity section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activity section of this 
notice would not be completed by the time the IHA expires and a renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
    <bullet> A request for renewal is received no later than 60 days 
prior to the needed renewal IHA effective date (recognizing that the 
renewal IHA expiration date cannot extend beyond 1 year from expiration 
of the initial IHA).
    <bullet> The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take); 
and,
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
    Upon review of the request for renewal, the status of the affected 
species or stocks, and any other pertinent information, NMFS determines 
that there are no more than minor changes in the activities, the 
mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.


[[Page 74478]]


    Dated: October 25, 2023.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2023-23970 Filed 10-30-23; 8:45 am]
BILLING CODE 3510-22-P


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