Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Pile Driving and Removal to Improve the Auke Bay East Ferry Terminal, 22411-22433 [2023-07729]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 88, Number 71 (Thursday, April 13, 2023)]
[Notices]
[Pages 22411-22433]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-07729]


-----------------------------------------------------------------------

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XC757]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Pile Driving and Removal to Improve 
the Auke Bay East Ferry Terminal

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.

-----------------------------------------------------------------------

SUMMARY: NMFS has received a request from the Alaska Department of 
Transportation and Public Facilities (ADOT&PF) for authorization to 
take marine mammals incidental to pile driving to improve the Auke Bay 
East Ferry Terminal in Juneau, 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

[[Page 22412]]

activities. NMFS is also requesting comments on a possible one-time, 1-
year renewal that could be issued under certain circumstances and if 
all requirements are met, as described in Request for Public Comments 
at the end of this notice. NMFS will consider public comments prior to 
making any final decision on the issuance of the requested MMPA 
authorization and agency responses will be summarized in the final 
notice of our decision.

DATES: Comments and information must be received no later than May 15, 
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 
[email protected].
    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 
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: Craig Cockrell, Office of Protected 
Resources, NMFS, (301) 427-8401. 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 above.

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 NOAA Administrative Order 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 September 13, 2022, NMFS received a request from ADOT&PF for an 
IHA to take marine mammals incidental to vibratory and impact pile 
driving to improve the Auke Bay East Ferry Terminal. Following NMFS' 
review of the application, ADOT&PF submitted a revised version on 
January 11, 2023. The application was deemed adequate and complete on 
February 14, 2023. The ADOT&PF's request is for the incidental take of 
small numbers of 11 species or stocks of marine mammals, in the form of 
Level B harassment for all and, for harbor seals and harbor porpoise, 
including take by Level A harassment. Neither ADOT&PF nor NMFS expect 
serious injury or mortality to result from this activity and, 
therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

    ADOT&PF is proposing maintenance improvements to the existing 
Alaska Marine Highway System (AMHS) Auke Bay East Berth marine 
terminal. The activity includes removal of existing piles and the 
installation of both temporary and permanent piles of various sizes. 
Takes of marine mammals by Level A and Level B harassment would occur 
due to both impact and vibratory pile driving and removal. The project 
would occur in Auke Bay which is located in southeast Alaska in close 
proximity to the City of Juneau. Construction activities are expected 
to over a four month period in fall 2023. It is expected to take up to 
61 days to complete the pile driving activities.
    The Auke Bay Ferry Terminal is located along the north shore of 
Auke Bay and is a major hub of the Southeast and Gulf of Alaska routes 
of the AMHS. The purpose of the Project is to restore the service life 
of the AMHS Auke Bay East Berth ferry terminal, which was originally 
built in 1982. The dolphins have undergone several repair projects and 
are currently in need of full replacement to keep the facility safe and 
usable for the AMHS vessels that frequent the facility.

Dates and Duration

    The proposed activities are expected to occur between October 1, 
2023 and September 30, 2024. It is expected to take up to 61 non-
consecutive days of in water work over a four month work window to 
complete the pile driving activities. Pile driving would be completed 
intermittently throughout the daylight hours. All pile driving is 
expected to be completed during one phase of construction.

Specific Geographic Region

    Auke Bay is an estuary at the southern end of Lynn Canal, located 
approximately 18 kilometers (km) (11 miles (mi)) north-northwest of 
downtown Juneau. The bay is one of many that lead to a larger system of

[[Page 22413]]

glacial fjords connecting various channels with the open ocean. Auke 
Bay is approximately 130 km (80.7 mi) inland from the Gulf of Alaska 
(Figure 1). Auke Bay contains several small islands and reefs within 
the 11 square kilometer (km\2\) (4.25 square mile (mi\2\)) embayment. 
While most of the bay is relatively shallow, reaching depths of 40 to 
60 meters (m) (131 to 197 feet (ft)), depths of more than 100 m (328 
ft) are found near Coghland Island (see Figure 1-2 in the IHA 
application). Pile installation and removal at the ferry terminal would 
occur in waters ranging in depth from less than 1 m (3.3 ft) near shore 
to approximately 11 m (35 ft).
BILLING CODE 3510-22-P
[GRAPHIC] [TIFF OMITTED] TN13AP23.113

BILLING CODE 3510-22-C

[[Page 22414]]

Detailed Description of the Specified Activity

    The ferry terminal improvements include the removal of 47 existing 
steel pipe piles. Once the existing piles are removed, up to 20 new 
steel pipe piles (30-inch (in) (76.2 centimeters (cm)) diameter; 10 
plumb, 10 battered) would be installed as berthing dolphins. Eight new 
steel pipe piles (24-in diameter (61 cm); 4 plumb, 4 battered) would be 
installed as float restraints. Four new steel pipe piles (18-in 
diameter (45.7 cm)) would be installed as gangway and platform support. 
The installation and removal of 32 temporary 24-in steel pipe piles 
would be completed to support permanent pile installation. Vibratory 
and impact hammers will be used for the installation and removal of all 
piles (Table 1). Removal of piles would be conducted using vibratory 
hammers. After new piles are set with a vibratory hammer, installed 
piles would be proofed with an impact hammer to verify the structural 
capacity of the pile embedment. The work would be completed at the 
existing Auke Bay Ferry Terminal in Juneau, Alaska. Work on the 
terminal would be completed within 1-year starting in October and 
completion in September.

                         Table 1--Number and Types of Piles To Be Installed and Removed
----------------------------------------------------------------------------------------------------------------
                                                                     Strikes     Duration   Piles per
                Pile diameter and type                  Number of   per pile     per pile      day      Days of
                                                          piles     (impact)    (minutes)    (range)    activity
----------------------------------------------------------------------------------------------------------------
                                                Pile Installation
----------------------------------------------------------------------------------------------------------------
30 in Steel Plumb Piles (Permanent; Berthing Dolphins)         10       1,000           60  1.5 (1-2)          7
30 in Steel Batter Piles (Permanent; Berthing                  10       1,000           60  1.5 (1-2)          7
 Dolphins)............................................
24 in Steel Plumb Piles (Permanent; Float Restraint)..          4       1,000           60  1.5 (1-2)          3
24 in Steel Batter Piles (Permanent; Float Restraint).          4       1,000           60  1.5 (1-2)          3
18 in Steel Plumb Piles (Permanent; Gangway/Platform            4         800           60  1.5 (1-2)          3
 Support).............................................
24 in Steel Piles (Temporary).........................         32         500           30    3 (2-4)         11
----------------------------------------------------------------------------------------------------------------
                                                  Pile Removal
----------------------------------------------------------------------------------------------------------------
18 in Steel Plumb Piles (Existing)....................         47         N/A           30    3 (2-4)         16
24 in Steel Piles (Temporary).........................         32         N/A           30    3 (2-4)         11
                                                       ---------------------------------------------------------
    Total.............................................        143  ..........  ...........  .........         61
----------------------------------------------------------------------------------------------------------------

    Above-water construction would include replacement of the catwalk 
access gangway, refurbishment of the catwalks, lighting upgrades along 
dolphins and catwalk, removal and replacement of electrical components 
as needed to perform dolphin replacement work, and installation of 
cathodic protection anodes on all piles. This above-water work is not 
expected to result in any take. Noise generated above the water would 
not be transmitted into the water and, there are no major pinniped 
haulouts located near the project area, therefore airborne noise is 
therefore not considered further in this document.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, incorporated here by reference, instead of 
reprinting the information. Additional information regarding population 
trends and threats may be found in NMFS' Stock Assessment Reports 
(SARs; 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. 2021 SARs, and NMFS has reviewed the most current 
information for all species, including those updated in the Draft 2022 
SARs.
    On January 24, 2023, NMFS published the draft 2022 SARs (https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region). The Alaska and Pacific Ocean SARs 
include proposed updates to the humpback whale and harbor porpoise 
stock structures. The new humpback whale stock structure, if finalized, 
would modify the MMPA-designated stocks to align more closely with the 
ESA-designated DPSs. The new harbor porpoise stock structure, if 
finalized, would split the Southeast Alaska stock into three new 
stocks. Please refer to the draft 2022 Alaska (Young et al., 2023) and 
Pacific Ocean SARs for additional information.

[[Page 22415]]

    NMFS Office of Protected Resources, Permits and Conservation 
Division has generally considered peer-reviewed data in draft SARs 
(relative to data provided in the most recent final SARs), when 
available, as the best available science, and has done so in this rule 
for all species and stocks, with the exception of a new proposal to 
revise humpback whale stock structure. Given that the proposed changes 
to the humpback whale stock structure involve application of NMFS's 
Guidance for Assessing Marine Mammals Stocks and could be revised 
following consideration of public comments, it is more appropriate to 
conduct our analysis in this proposed IHA based on the status quo stock 
structure identified in the most recent final SARs (2021; Carretta et 
al., 2022; Muto et al., 2022).
    All values presented in Table 2 are the most recent available at 
the time of publication (including from the draft 2022 SARs) and are 
available online at: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments).

                                              Table 2--Species Likely Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         ESA/ MMPA status;   Stock abundance (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae (rorquals):
    Humpback whale..................  Megaptera novaeangliae.  Central North Pacific..  -/-; Y              10,103 (0.3, 7,890,           3.4       4.46
                                                                                                             2006).
    Minke whale.....................  Balaenoptera             Alaska.................  -/-; N              N/A (N/A, N/A, N/A)...        UND          0
                                       acutorostrada.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Killer whale....................  Orcinus orca...........  Alaska Resident........  -/-; N              1,920 (N/A, 1,920,             19        1.3
                                                                                                             2019).
                                                               West Coast Transient...  -/-; N              349 (N/A, 349, 2018)..        3.5        0.4
    Pacific white-sided dolphin.....  Lagenorhynchus           North Pacific..........  -/-; N              26,880 (N/A, N/A,             UND          0
                                       obliquidens.                                                          1990).
Family Phocoenidae (porpoises):
    Harbor porpoise.................  Phocoena phocoena......  Southern Southeast       -/-; Y              890 (0.37; 610; 2019).        6.1        7.4
                                                                Alaska Inland Waters.
    Dall's porpoise.................  Phocoenoides dalli.....  Alaska.................  -/-; N              UND (UND, UND, 2015)..        UND         37
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    Steller sea lion................  Eumetopias jubatus.....  Eastern DPS............  -/-; N              43,201 (N/A, 43,201,        2,592        112
                                                                                                             2017).
                                                               Western DPS............  E/D; Y              52,932 (N/A, 53,932,          318        254
                                                                                                             2019).
    California sea lion.............  Zalophus californianus.  U.S....................  -/-; N              257,606 (N/A, 233,515,     14,011       >321
                                                                                                             2014).
    Northern fur seal...............  Callorhinus ursinus....  Eastern Pacific........  -/-; Y              626,618 (0.2, 530,376,     11,403        373
                                                                                                             2019).
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulina.........  Lynn Canal/Stephens      -/-; N              13,388 (N/A, 11,867,          214         50
                                                                Passage.                                     2016).
    Northern Elephant Seal..........  Mirounga angustirostris  California.............  -/-; N              187,386 (N/A, 85,369,       5,122       13.7
                                                                                                             2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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: 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.
\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, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.

    As indicated above, all 11 species (with 13 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 survey areas are included in Table 3-
1 of the IHA application. The spatial and temporal occurrence of gray 
whales and fin whales in the area is such that take is not expected to 
occur. Sightings of gray whales and fin whales are uncommon in the 
inland waters of southeast Alaska. These species are typically seen 
closer to the open waters of the Gulf of Alaska. Additionally, the 
timing of the project (October-December) coincides with the period when 
these species are expected to be further south in their respective 
breeding areas. Take of gray whales and fin whales has not been 
requested nor is proposed to be authorized and these species are not 
considered further in this document. The take of Northern fur seals was 
not requested by the applicant, but further communication with the NMFS 
Alaska Regional Office resulted in their inclusion in species that 
inhabit the area as well as being at risk for take during the 
construction activities (Wright, S., pers. comm.).

Humpback Whale

    Humpback whales in the project area are from the Central North 
Pacific stock but may be of the Hawaii or Mexico Distinct Population 
Segments (DPS). Humpback whales migrate to southeast Alaska in spring 
to feed after months of fasting in equatorial breeding grounds in 
Hawaii and Mexico. Humpback whales found in the project areas are 
predominantly members of the Hawaii DPS (98 percent probability in

[[Page 22416]]

Southeast Alaska), which is not listed under the ESA. However, based on 
a comprehensive photo-identification study, members of the Mexico DPS, 
which is listed as threatened, have a small potential to occur in the 
project location (2 percent probability in Southeast Alaska) (Wade, 
2021). Peak abundance of humpback whales in southeast Alaska typically 
occurs during late summer to early fall. Most humpback whales begin 
returning to southern breeding grounds in fall or winter. However, due 
to temporal overlap between whales departing and returning, humpbacks 
can be found in Alaskan feeding grounds in every month of the year 
(Baker et al., 1985; Straley, 1990; Wynne and Witteveen, 2009). It is 
also common for some humpback whales to overwinter in areas of 
southeast Alaska. It is thought that those humpbacks that remain in 
southeast Alaska do so in response to the availability of winter 
schools of fish, such as herring (Straley, 1990).
    Southeast Alaska is considered a biologically important area for 
feeding humpback whales between March and May (Ellison et al. 2012). 
Most humpback whales migrate to other regions during winter to breed, 
but over-wintering (non-breeding) humpback whales have been noted and 
may be increasingly common (Straley, 1990). In Alaska, humpback whales 
filter feed on tiny crustaceans, plankton, and small fish such as 
walleye pollock, Pacific sand lance, herring, eulachon, and capelin 
(Witteveen et al., 2012). It is common to observe groups of humpback 
whales cooperatively bubble feeding.
    Use of Auke Bay by humpback whales is intermittent and irregular 
year-round. During winter, researchers have documented 1 to 19 
individual humpback whales per month in waters close to the project 
area, including Lynn Canal (Moran et al., 2018a; Straley et al., 2018). 
Group sizes in southeast Alaska generally range from one to four 
individuals (Dahlheim et al., 2009).

Minke Whale

    Minke whales in Southeast Alaska are part of the Alaska stock (Muto 
et al., 2022). Dedicated surveys for cetaceans in Southeast Alaska 
found that minke whales were scattered throughout inland waters from 
Glacier Bay and Icy Strait to Clarence Strait, with small 
concentrations near the entrance of Glacier Bay. All sightings were of 
single minke whales, except for a single sighting of multiple minke 
whales. Surveys took place in spring, summer, and fall, and minke 
whales were present in low numbers in all seasons and years. No 
information appears to be available on the winter occurrence of minke 
whales in Southeast Alaska (Dahlheim et al., 2009). Anecdotal 
observations suggest that minke whales do not enter Auke Bay but their 
occurrence in Southeast Alaska could result in their presences in the 
Project area.

Killer Whale

    Killer whales have been observed in all the world's oceans, but the 
highest densities occur in colder and more productive waters found at 
high latitudes (NMFS 2016a). Killer whales occur along the entire 
Alaska coast, in British Columbia and Washington inland waterways, and 
along the outer coasts of Washington, Oregon, and California (NMFS, 
2016a). There are three distinct ecotypes, or forms, of killer whales 
recognized: resident, transient, and offshore. The three ecotypes 
differ morphologically, ecologically, behaviorally, and genetically. 
Based on data regarding association patterns, acoustics, movements, and 
genetic differences, eight killer whale stocks are now recognized 
within the Pacific U.S. Exclusive Economic Zone. This application 
considers only the Eastern North Pacific Alaska Resident Stock (Alaska 
Resident Stock), Eastern North Pacific Northern Resident Stock 
(Northern Resident Stock), and West Coast Transient Stock, because all 
other stocks occur outside the geographic area under consideration 
(Muto et al., 2022).
    Transient killer whales hunt and feed primarily on marine mammals, 
while residents forage primarily on fish. Transient killer whales feed 
primarily on harbor seals, Dall's porpoises, harbor porpoises, and sea 
lions. Resident killer whale populations in the eastern North Pacific 
feed mainly on salmonids, showing a strong preference for Chinook 
salmon (NMFS, 2016a).
    No systematic studies of killer whales have been conducted in or 
around Auke Bay. Killer whales were observed infrequently (on 11 of 135 
days) during monitoring nearby in Hoonah, 54 km west of Auke Bay, and 
most were recorded in deeper, offshore waters (Berger ABAM, 2016). 
Dalheim et al. (2009) observed transient killer whales within Lynn 
Canal, Icy Strait, Stephens Passage, Frederick Sound, and upper Chatham 
Strait. Transient killer whales tend to transit through Lynn Canal and 
occasionally enter Auke Bay to target local harbor seal, harbor 
porpoise, or Steller sea lion populations, but do not linger in the 
Project area (K. Savage, pers. comm.).

Pacific White-Side Dolphin

    Pacific white-sided dolphins are a pelagic species inhabiting 
temperate waters of the North Pacific Ocean and along the coasts of 
California, Oregon, Washington, and Alaska (Muto et al. 2022). Despite 
their distribution mostly in deep, offshore waters, they may also be 
found over the continental shelf and in nearshore waters, including 
inland waters of Southeast Alaska (Ferrero and Walker, 1996). They prey 
on squid and small schooling fish such as capelin, sardines, and 
herring, are known to work in groups to herd schools of fish, and can 
dive underwater for up to 6 minutes to feed (Morton, 2006).
    Scientific studies and data are lacking relative to the presence or 
abundance of Pacific white-sided dolphins in or near Auke Bay. When 
Pacific white-sided dolphins have been observed, sighting rates were 
highest in spring and decreased throughout summer and fall (Dahlheim et 
al., 2009). Most observations of Pacific white-sided dolphins occur off 
the outer coast or in inland waterways near entrances to the open 
ocean. According to NOAA (Muto et al., 2022), aerial surveys in 1997 
sighted one group of 164 Pacific white-sided dolphins in the Dixon 
Entrance to the south of Auke Bay. These observational data, combined 
with anecdotal information, indicate that there is a small potential 
for Pacific white-sided dolphins to occur in the Project area.

Harbor Porpoise

    The Southeast Alaska stock of harbor porpoises ranges from Cape 
Suckling to the Canada border (Muto et al., 2022). Harbor porpoises 
frequent primarily coastal waters in southeast Alaska (Dalheim et al., 
2009) and occur most frequently in waters less than 100 m (328 ft) deep 
(Hobbs and Waite, 2010). Harbor porpoises forage in waters less than 
200 m (656 ft) deep on small pelagic schooling fish such as herring, 
cod, pollock, octopus, smelt, and bottom-dwelling fish, occasionally 
feeding on squid and crustaceans (Bj[oslash]rge and Tolley 2009; Wynne 
et al., 2011). Calving generally occurs from May to August, but can 
vary by region.
    Although there have been no systematic studies or observations of 
harbor porpoises specific to Auke Bay, there is the potential for them 
to occur within the project area. Abundance data for harbor porpoises 
in southeast Alaska were collected during 18 seasonal surveys spanning 
22 years, from 1991 to 2012. During that study, a total of 398 harbor 
porpoises were observed in the northern inland waters of southeast

[[Page 22417]]

Alaska, including Lynn Canal (Dahlheim et al., 2015). Recent monitoring 
from ADOT&PF from within Auke Bay observed a total of 28 animals over a 
25 day period (ADOT&PF, 2021. NMFS also completed observations in Auke 
Bay where 62 groups of harbor porpoises were seen over a 60-hour 
period. The survey was conducted from March through June in 2021.

Dall's Porpoise

    Dall's porpoises are found throughout the North Pacific, from 
southern Japan to southern California and north to the Bering Sea. All 
Dall's porpoises in Alaska are members of the Alaska stock, and those 
off California, Oregon, and Washington are part of a separate stock. 
This species can be found in offshore, inshore, and nearshore habitat, 
but prefers waters more than 183 meters deep (Dahlheim et al., 2009; 
Jefferson, 2009).
    No systematic studies of Dall's porpoise abundance or distribution 
have occurred in Auke Bay; however, Dall's porpoises have been 
consistently observed in Lynn Canal, Stephens Passage, upper Chatham 
Strait, Frederick Sound, and Clarence Strait (Dalheim et al., 2000). 
The species is generally found in waters in excess of 600 feet (183 
meters) deep, which do not occur in Auke Bay. Despite generalized water 
depth preferences, Dall's porpoises may occur in shallower waters. 
Moran et al. (2018a) recently mapped Dall's porpoise distributions in 
bays, shallow water, and nearshore areas of Prince William Sound, 
habitats not typically utilized by this species. A lone Dall's porpoise 
was sighted in the Level B harassment zone during construction 
activities conducted by ADOT&PF at Auke Bay in 2021 (ADOT&PF, 2021). If 
Dall's porpoises occur in the Project area, they will likely be present 
in March or April, given strong seasonal patterns observed in nearby 
areas of Southeast Alaska (Dalheim et al., 2009).

Steller Sea Lion

    Steller sea lions are found throughout the northern Pacific Ocean, 
including coastal and inland waters from Russia (Kuril Islands and the 
Sea of Okhotsk), east to Alaska, and south to central California 
(A[ntilde]o Nuevo Island). Steller sea lions were listed as threatened 
range-wide under the ESA on November 26, 1990 (55 FR 49204, November 
26, 1990); they were subsequently partitioned into the western and 
eastern DPSs (wDPS and eDPS, respectively) in 1997 (Allen and Angliss, 
2010). The eDPS remained classified as threatened (62 FR 24345, May 5, 
1997) until it was delisted in November 2013, while the wDPS (those 
individuals west of 144[deg] W longitude or Cape Suckling, Alaska) was 
upgraded to endangered status following separation of the stocks, and 
it remains listed as endangered.
    The majority of Steller sea lions that inhabit Southeast Alaska are 
part of the eDPS; however, branded individuals from the wDPS make 
regular movements across the 144[deg] longitude boundary to the 
northern ``mixing zone'' haulouts and rookeries within southeast Alaska 
(Jemison et al., 2013). While haulouts and rookeries in the northern 
portion of Southeast Alaska may be important areas for wDPS animals, 
there continues to be little evidence that their regular range extends 
to the southern haulouts and rookeries in Southeast Alaska (Jemison et 
al., 2018). However, genetic data analyzed in Hastings et al. (2020) 
indicated that up to 1.4 percent of Steller sea lions near the Project 
area may be members of the wDPS, which NMFS recommends using in their 
2020 guidance (NMFS, 2020).
    Steller sea lions are opportunistic predators, feeding primarily on 
a wide variety of fishes and cephalopods, including Pacific herring 
(Clupea pallasi), walleye pollock (Gadus chalogramma), capelin 
(Mallotus villosus), Pacific sand lance (Ammodytes hexapterus), Pacific 
cod (Gadus machrocephalus), salmon (Oncorhynchus spp.), and squid 
(Teuthida spp.) (Jefferson et al., 2008; Wynne et al., 2011). Steller 
sea lions do not generally eat every day, but tend to forage every one 
to two days and return to haulouts to rest between foraging trips 
(Merrick and Loughlin, 1997; Rehberg et al., 2009).
    The action area is not located in or near designated critical 
habitat for the wDPS of Steller sea lions. In southeast Alaska, 
critical habitat for the wDPS includes a terrestrial zone, an aquatic 
zone, and an in-air zone that extends 3,000 ft (0.9 km) landward, 
seaward, and above, respectively, any designated major rookery and 
major haulout. Steller sea lions are common within the project area; 
however, systematic counts or surveys have not been completed. The 
species generally occurs in Auke Bay only during winter. In the marine 
mammal monitoring report for a project completed at the same facility 
by ADOT, 30 Steller sea lions were observed within the behavioral 
disturbance zone during pile driving or drilling (i.e., documented as 
Level B harassment take) (ADOT&PF, 2021). The Auke Bay boating 
community observes Steller sea lions transiting between Auke Bay and 
the Benjamin Island haulout regularly during winter and provides 
anecdotal reports of Steller sea lions utilizing Fritz Cove in winter 
months. Most individuals that frequent Auke Bay use the major haulout 
on Benjamin Island in Lynn Canal (approximately 34 mi (54.7 km) from 
the project location), but several other haulouts are located within 20 
to 30 km (12 to 19 mi) of the project area.

California Sea Lion

    California sea lions have been separated into five genetically 
distinct stocks, with the U.S. Stock also known as the Pacific 
Temperate Stock (Carretta et al., 2022). Male California sea lions 
disperse widely from their breeding rookeries in southern California to 
forage as far north as Canada (Carretta et al., 2022), with some 
individuals observed dispersing farther north.
    The U.S. stock of California sea lions have a wide range, typically 
from the border of the United States and Mexico (NMFS, 2019c). During 
the winter males commonly migrate to feeding grounds off California, 
Oregon, Washington, British Columbia and recently Southeast Alaska. 
There is an active unusual mortality event declared for the U.S. stock 
of California sea lions but this is mostly limited to southern 
California. Females and pups on the other hand stay close to breeding 
colonies until the pups have weened. The furthest north females have 
been observed is off the coast of Washington and Oregon during warm 
water years (NMFS, 2019c). While California sea lions aren't common in 
Alaska, one was present on the docks in Statter Harbor within Auke Bay 
in 2017 (NOAA, 2017).
    California sea lions feed primarily offshore in coastal waters. 
They are opportunistic predators and eat a variety of prey including 
squid, anchovies, mackerel, rockfish and sardines (NMFS, 2019c). 
California sea lion breeding areas are mostly in southern California 
and are not expected to spatially overlap with the project area.

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. 
During the summer breeding season, most of the worldwide population is 
found on the Pribilof Islands (St. Paul Island and St. George Island) 
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, and on the Farallon Islands off central 
California (Muto et al. 2022). Northern fur seals feed on a variety of 
prey including, squid, walleye pollock

[[Page 22418]]

(Gadus chalcogrammus), Pacific hearing (Clupea pallasii), and capelin 
(Mallotus villosus) (Gomez et al., 2015). Breeding and important 
haulouts areas are not expected to spatially overlap with the project 
area.
    Northern fur seals are rare in the Auke Bay in general, but one 
lone animal was sighted swimming in the Gastineau Channel in 2019. In 
2021 three Northern fur seals were stranded near Juneau, one in 
Gastineau Channel, one onshore about two miles Northwest of the action 
area, and a third on the west side of Douglas Island. Early in 2023 
another northern fur seal was stranded in Sitka harbor (Wright, S., 
pers. comm.).

Harbor Seal

    Harbor seals range from Baja California north along the west coasts 
of California, Oregon, Washington, British Columbia, and Southeast 
Alaska; west through the Gulf of Alaska, Prince William Sound, and the 
Aleutian Islands; and north in the Bering Sea to Cape Newenham and the 
Pribilof Islands. Harbor seals occur year-round in the inside passages 
of southeast Alaska and are regularly sighted in Auke Bay. Harbor seals 
forage on fish and invertebrates (Orr et al., 2004) including capelin, 
eulachon (Thaleichthys pacificus), cod, pollock, flatfish, shrimp, 
octopus, and squid (Wynne, 2012). They are opportunistic feeders that 
forage in marine, estuarine, and occasionally freshwater habitat, 
adjusting their foraging behavior to take advantage of prey that are 
locally and seasonally abundant (Payne and Selzer, 1989). Research has 
demonstrated that harbor seals conduct both shallow and deep dives 
while foraging (Tollit et al., 1997), depending on prey availability. 
Harbor seals usually give birth to a single pup between May and mid-
July; birthing locations are dispersed over several haulout sites and 
not confined to major rookeries (Klinkhart et al., 2008). Harbor seals 
haul out on rocks, reefs, beaches, and drifting glacial ice. They are 
non-migratory; their local movements are associated with tides, 
weather, season, food availability, and reproduction, as well as sex 
and age class (Swain et al., 1996; Lowry et al., 2001; Boveng et al., 
2012).
    Harbor seals are commonly sighted in the waters of the inside 
passages throughout Southeast Alaska. They occur year-round within the 
Project area and are regularly sighted in Auke Bay, including Statter 
Harbor within Auke Bay. NOAA aerial survey data indicate that groups 
ranging from 10 to 52 seals could be present within the Project area 
during summer at haulouts on the western side of Coghlan Island, as 
well as on Battleship Island (E. Richmond, pers. comm.). Harbor seals 
were observed in all months of ADOT&PF's 2021 project in Auke Bay 
(AKDOT&PF, 2021). Harbor seals are known to be curious and may approach 
novel activity and could enter the Project area during pile 
installation and removal.

Northern Elephant Seal

    Northern elephant seals breed and give birth in California (U.S.) 
and Baja California (Mexico), primarily on offshore islands, from 
December to March (Stewart et al. 1994). Spatial segregation in 
foraging areas between males and females is evident from satellite tag 
data (Le Beouf et al., 2000). Males migrate to the Gulf of Alaska and 
western Aleutian Islands along the continental shelf to feed on benthic 
prey, while females migrate to pelagic areas in the Gulf of Alaska and 
the central North Pacific to feed on pelagic prey (Le Beouf et al., 
2000).
    Auke Bay is an unlikely area for an occurrence, as northern 
elephant seals generally feed along the continental shelf break (Le 
Boeuf et al., 2000) and are not expected to spend time in shallow 
areas. No sightings of elephant seals have been documented near Auke 
Bay; however, protected species observers (PSOs) at a ADOT&PF project 
site in Ketchikan (460 kilometers south of Auke Bay) reported sightings 
of a northern elephant seal on multiple days (C. Gentemann, pers. 
comm., April 8, 2022). Additional sightings of northern elephant seals 
around the state concurrent with the Ketchikan sighting were reported 
in Seward, King Cove, and Kodiak (L. Davis, pers. comm., April 14, 
2022). Breeding and important haulouts areas are not expected to 
spatially overlap with the project area.

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).


[[Page 22419]]

    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 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 section, and the Proposed Mitigation section, to draw 
conclusions regarding the likely impacts of these activities on the 
reproductive success or survivorship of individuals and whether those 
impacts are reasonably expected to, or reasonably likely to, adversely 
affect the species or stock through effects on annual rates of 
recruitment or survival.

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound is defined as the all-encompassing 
sound in a given place and is usually a composite of sound from many 
sources both near and far. The sound level of an area is defined by the 
total acoustical energy being generated by known and unknown sources. 
These sources may include physical (e.g., waves, wind, precipitation, 
earthquakes, ice, atmospheric sound), biological (e.g., sounds produced 
by marine mammals, fish, and invertebrates), and anthropogenic sound 
(e.g., vessels, dredging, aircraft, construction).
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 dB 
from day to day (Richardson et al., 1995). The result is that, 
depending on the source type and its intensity, sound from the 
specified activity may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals.
    In-water construction activities associated with the project would 
include impact pile driving, vibratory pile driving, and vibratory pile 
removal. The sounds produced by these activities fall into one of two 
general sound types: impulsive and non-impulsive. Impulsive sounds 
(e.g., explosions, gunshots, sonic booms, impact pile driving) are 
typically transient, brief (less than 1 second), broadband, and consist 
of high peak sound pressure with rapid rise time and rapid decay (ANSI, 
1986; NIOSH, 1998; ANSI, 2005; 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 raid rise/decay time that 
impulsive sounds do (ANSI, 1995; NIOSH, 1998; NMFS, 2018). The 
distinction between these two sound types is important because they 
have differing potential to cause physical effects, particularly with 
regard to hearing (e.g., Ward, 1997 in Southall, et al. 2007).
    Two types of pile hammers would be used on this project: impact and 
vibratory. Impact hammers operate by repeatedly dropping a heavy piston 
onto a pile to drive the pile into the substrate. Sound generated by 
impact hammers is characterized by rapid rise times and high peak 
levels, a potentially injurious combination (Hastings and Popper, 
2005). Vibratory hammers install piles by vibrating them and allowing 
the weight of the hammer to push them into the sediment. Vibratory 
hammers produce significantly less sound than impact hammers. Peak 
sound pressure levels (SPLs) may be 180 dB or greater, but are 
generally 10 to 20 dB lower than SPLs generated during impact pile 
driving of the same-sized pile (Oestman, et al. 2009). Rise time is 
slower, reducing the probability and severity of injury, and sound 
energy is distributed over a greater amount of time (Nedwell and 
Edwards, 2002; Carlson, et al. 2005).
    The likely or possible impacts of ADOT&PF's proposed activity on 
marine mammals could involve both non-acoustic and acoustic stressors. 
Potential non-acoustic stressors could result from the physical 
presence of the equipment and personnel; however, any impacts to marine 
mammals are expected to primarily be acoustic in nature.

Auditory Effects

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving and removal is the primary means by which 
marine mammals may be harassed from ADOT&PF's specified activity. In 
general, animals exposed to natural or anthropogenic sound may 
experience physical and psychological effects, ranging in magnitude 
from none to severe (Southall et al., 2007). Exposure to pile driving 
noise has the potential to result in auditory threshold shifts and 
behavioral reactions (e.g., avoidance, temporary cessation of foraging 
and vocalizing, changes in dive behavior). Exposure to anthropogenic 
noise can also lead to non-observable physiological responses such an 
increase in stress hormones. Additional noise in a marine mammal's 
habitat can mask acoustic cues used by marine mammals to carry out 
daily functions such as communication and predator and prey detection. 
The effects of pile driving noise on marine mammals are dependent on 
several factors, including, but not limited to, sound type (e.g., 
impulsive vs. non-impulsive), the species, age and sex class (e.g., 
adult male vs. mom with calf), duration of exposure, the distance 
between the pile and the animal, received levels, behavior at time of 
exposure, and previous history with exposure (Wartzok et al., 2004; 
Southall et al., 2007). Here we discuss physical auditory effects 
(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

[[Page 22420]]

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 (see Ward et al., 1958, 1959; Ward, 1960; 
Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; Henderson et 
al., 2008). PTS levels for marine mammals are estimates, as with the 
exception of a single study unintentionally inducing PTS in a harbor 
seal (Kastak et al., 2008), there are no empirical data measuring PTS 
in marine mammals largely due to the fact that, for various ethical 
reasons, experiments involving anthropogenic noise exposure at levels 
inducing PTS are not typically pursued or authorized (NMFS, 2018).
    Temporary Threshold Shift (TTS)--A temporary, reversible increase 
in the threshold of audibility at a specified frequency or portion of 
an individual's hearing range above a previously established reference 
level (NMFS, 2018). Based on data from cetacean TTS measurements (see 
Southall et al., 2007), a TTS of 6 dB is considered the minimum 
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Schlundt et 
al., 2000; Finneran et al., 2000, 2002). As described in Finneran 
(2015), marine mammal studies have shown the amount of TTS increases 
with cumulative sound exposure level (SELcum) in an accelerating 
fashion: At low exposures with lower SELcum, the amount of TTS is 
typically small and the growth curves have shallow slopes. At exposures 
with higher higher SELcum, the growth curves become steeper and 
approach linear relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced, TTS can have effects on marine mammals ranging 
from discountable to serious (similar to those discussed in auditory 
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).
    Installing piles requires a combination of impact pile driving and 
vibratory pile driving. For the project, these activities would not 
occur at the same time and there would likely be pauses in activities 
producing the sound during each day. Given these pauses and that many 
marine mammals are likely moving through the action area and not 
remaining for extended periods of time, the potential for TS declines.

Behavioral Effects

    Exposure to noise from pile driving and removal 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; NRC, 2005).
    Disturbance may result in changing durations of surfacing and 
dives, number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities; changing/cessation of certain 
behavioral activities (such as socializing or feeding); visible startle 
response or aggressive behavior (such as tail/fluke slapping or jaw 
clapping); avoidance of areas where sound sources are located. 
Pinnipeds may increase their haul out time, possibly to avoid in-water 
disturbance (Thorson and Reyff, 2006). Behavioral responses to sound 
are highly variable and context-specific and any reactions depend on 
numerous intrinsic and extrinsic factors (e.g., species, state of 
maturity, experience, current activity, reproductive state, auditory 
sensitivity, time of day), as well as the interplay between factors 
(e.g., Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 
2007; Weilgart, 2007; Archer et al. 2010). Behavioral reactions can 
vary not only among individuals but also within an individual, 
depending on previous experience with a sound source, context, and 
numerous other factors (Ellison et al., 2012), and can vary depending 
on characteristics associated with the sound source (e.g., whether it 
is moving or stationary, number of sources, distance from the source). 
In general, pinnipeds seem more tolerant of, or at least habituate more 
quickly to, potentially disturbing underwater sound than do cetaceans, 
and generally seem to be less responsive to exposure to industrial 
sound than most cetaceans. For a review of studies involving marine 
mammal behavioral responses to sound, see Southall et al., 2007; Gomez 
et al., 2016; and Southall et al., 2021 reviews.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known

[[Page 22421]]

foraging areas, the appearance of secondary indicators (e.g., bubble 
nets or sediment plumes), or changes in dive behavior. As for other 
types of behavioral response, the frequency, duration, and temporal 
pattern of signal presentation, as well as differences in species 
sensitivity, are likely contributing factors to differences in response 
in any given circumstance (e.g., Croll et al., 2001; Nowacek et al., 
2004; Madsen et al., 2006; Yazvenko et al., 2007). A determination of 
whether foraging disruptions incur fitness consequences would require 
information on or estimates of the energetic requirements of the 
affected individuals and the relationship between prey availability, 
foraging effort and success, and the life history stage of the animal.
    The area likely impacted by the project is relatively small 
compared to the available habitat in the surrounding waters of Lynn 
Canal. Although Auke Bay is part of an identified Biologically 
Important Area for feeding humpback whales (Ferguson et al., 2015), the 
timing of the BIA (March through November) only overlaps with the 
proposed timing of the in-water construction (October through January) 
for two months. Additionally, humpback foraging efforts within Auke Bay 
itself are intermittent and irregular across seasons.
    In 2021, ADOT&PF documented observations of marine mammals during 
construction activities (i.e., pile driving) at the Auke Bay Ferry 
Terminal (84 FR 56767, October 23, 2019). In the marine mammal 
monitoring report for that project (State of Alaska, 2021), 30 Steller 
sea lions were observed within the behavioral disturbance zone during 
pile driving or drilling (i.e., documented as Level B harassment take). 
Twenty eight harbor seals were observed within the disturbance zone 
during pile driving activities. A lone Dall's porpoise was sighted in 
the Level B harassment zone during construction. During the 
construction activities six takes by Level B harassment of humpback 
whales occurred. No signs of disturbance were noted for any of these 
species that were present in the harassment zones. Given the 
similarities in activities and habitat and the fact the same species 
are involved, we expect similar behavioral responses of marine mammals 
to the specified activity. That is, disturbance, if any, is likely to 
be temporary and localized (e.g., small area movements). Monitoring 
reports from other recent pile driving projects have observed similar 
behaviors.
    Masking--Sound can disrupt behavior through masking, or interfering 
with, an animal's ability to detect, recognize, or discriminate between 
acoustic signals of interest (e.g., those used for intraspecific 
communication and social interactions, prey detection, predator 
avoidance, navigation) (Richardson et al., 1995). Masking occurs when 
the receipt of a sound is interfered with by another coincident sound 
at similar frequencies and at similar or higher intensity, and may 
occur whether the sound is natural (e.g., snapping shrimp, wind, waves, 
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar, 
seismic exploration) in origin. The ability of a noise source to mask 
biologically important sounds depends on the characteristics of both 
the noise source and the signal of interest (e.g., signal-to-noise 
ratio, temporal variability, direction), in relation to each other and 
to an animal's hearing abilities (e.g., sensitivity, frequency range, 
critical ratios, frequency discrimination, directional discrimination, 
age or TTS hearing loss), and existing ambient noise and propagation 
conditions. Masking of natural sounds can result when human activities 
produce high levels of background sound at frequencies important to 
marine mammals. Conversely, if the background level of underwater sound 
is high (e.g., on a day with strong wind and high waves), an 
anthropogenic sound source would not be detectable as far away as would 
be possible under quieter conditions and would itself be masked. Auke 
Bay is home to a busy ferry terminal as well as moorage for small 
private vessels that transit the area on a regular basis; therefore, 
background sound levels in the harbor are already elevated.
    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 exceeding the acoustic thresholds. We recognize that pinnipeds 
in the water could be exposed to airborne sound that may result in 
behavioral harassment when looking with their heads above water. Most 
likely, airborne sound would cause behavioral responses similar to 
those discussed above in relation to underwater sound. For instance, 
anthropogenic sound could cause hauled-out pinnipeds to exhibit changes 
in their normal behavior, such as reduction in vocalizations, or cause 
them to temporarily abandon the area and move further from the source. 
However, these animals would previously have been `taken' because of 
exposure to underwater sound above the behavioral harassment 
thresholds, which are in all cases larger than those associated with 
airborne sound. Thus, the behavioral harassment of these animals is 
already accounted for in these estimates of potential take. Therefore, 
we do not believe that authorization of incidental take resulting from 
airborne sound for pinnipeds is warranted, and airborne sound is not 
discussed further here.

Marine Mammal Habitat Effects

    ADOT&PF's construction activities could have localized, temporary 
impacts on marine mammal habitat by increasing in-water sound pressure 
levels and slightly decreasing water quality. Construction activities 
are of short duration and would likely have temporary impacts on marine 
mammal habitat through increases in underwater sound. Increased noise 
levels may affect acoustic habitat (see masking discussion above) and 
adversely affect marine mammal prey in the vicinity of the project area 
(see discussion below). During pile driving, elevated levels of 
underwater noise would ensonify Auke Bay where both fish and mammals 
may occur and could affect foraging success.
    In-water pile driving and pile removal would also cause short-term 
effects on water quality due to increased turbidity. Local currents are 
anticipated to disburse suspended sediments produced by project 
activities at moderate to rapid rates depending on tidal stage. ADOT&PF 
would employ standard construction best management practices, thereby 
reducing any impacts. Considering the nature and duration of the 
effects, combined with the measures to reduce turbidity, the impact 
from increased turbidity levels is expected to be discountable.
    Pile installation and removal may temporarily increase turbidity 
resulting from suspended sediments. Any increases would be temporary, 
localized, and minimal. ADOT&PF must comply with state water quality 
standards during these operations by limiting the extent of turbidity 
to the immediate project area. In general, turbidity associated with 
pile installation is localized to about a 25-foot radius around the 
pile (Everitt et al. 1980). Cetaceans are not expected to enter the 
harbor and be close enough to the project pile driving areas to

[[Page 22422]]

experience effects of turbidity, and any pinnipeds would likely be 
transiting the area and could avoid localized areas of turbidity. 
Therefore, the impact from increased turbidity levels is expected to be 
discountable to marine mammals. Furthermore, pile driving and removal 
at the project site would not obstruct movements or migration of marine 
mammals.

Effects on Prey

    Construction activities would produce continuous (i.e., vibratory 
pile driving) and impulsive (i.e., impact driving) sounds. Fish react 
to sounds that are especially strong and/or intermittent low-frequency 
sounds. Short duration, sharp sounds can cause overt or subtle changes 
in fish behavior and local distribution. Hastings and Popper (2005) 
identified several studies that suggest fish may relocate to avoid 
certain areas of sound energy. Additional studies have documented 
effects of pile driving on fish, although several are based on studies 
in support of large, multiyear bridge construction projects (e.g., 
Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Sound pulses 
at received levels may cause noticeable changes in behavior (Pearson et 
al., 1992; Skalski et al., 1992). SPLs of sufficient strength have been 
known to cause injury to fish and fish mortality.
    Impacts on marine mammal prey (i.e., fish or invertebrates) of the 
immediate area due to the acoustic disturbance are possible. The 
duration of fish or invertebrate avoidance or other disruption of 
behavioral patterns in this area after pile driving stops is unknown, 
but a rapid return to normal recruitment, distribution and behavior is 
anticipated. Further, significantly large areas of fish and marine 
mammal foraging habitat are available in the nearby vicinity in Lynn 
Canal.
    The duration of the construction activities is relatively short, 
with pile driving and removal activities expected to take only 61 days. 
Each day, construction would occur for no more than 12 hours during the 
day and pile driving activities would be restricted to daylight hours. 
The most likely impact to fish from pile driving activities at the 
project area would be temporary behavioral avoidance of the area. In 
general, impacts to marine mammal prey species are expected to be minor 
and temporary due to the short timeframe for the project.
    Construction activities, in the form of increased turbidity, have 
the potential to adversely affect fish in the project area. Increased 
turbidity is expected to occur in the immediate vicinity (on the order 
of 10 feet (3 meters) or less) of construction activities. However, 
suspended sediments and particulates are expected to dissipate quickly 
within a single tidal cycle. Given the limited area affected and high 
tidal dilution rates any effects on fish are expected to be minor or 
negligible. In addition, best management practices would be in effect, 
which would limit the extent of turbidity to the immediate project 
area.
    In summary, given the short daily duration of sound associated with 
individual pile driving and events and the relatively small areas being 
affected, pile driving activities associated with the proposed action 
are not likely to have a permanent, adverse effect on any fish habitat, 
or populations of fish species. Thus, we conclude that impacts of the 
specified activity are not likely to have more than short-term adverse 
effects on any prey habitat or populations of prey species. Further, 
any impacts to marine mammal habitat are not expected to result in 
significant or long-term consequences for individual marine mammals, or 
to contribute to adverse impacts on their populations.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which would 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. Authorized takes would primarily be by Level B harassment, 
as use of the acoustic sources (i.e., impact and vibratory pile 
driving) has the potential to result in disruption of behavioral 
patterns for individual marine mammals. There is also some potential 
for auditory injury (Level A harassment) to result, primarily for high 
frequency cetaceans and phocids because predicted auditory injury zones 
are larger than for other hearing groups. 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 would be behaviorally 
harassed or incur some degree of permanent hearing impairment; (2) the 
area or volume of water that would 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, 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 (root mean square (RMS) SPL) of 
120 dB (referenced to 1 micropascal (re 1 microPascal ([mu]Pa)) for 
continuous (e.g., vibratory pile-driving) and above RMS SPL 160 dB re 1 
[mu]Pa for non-explosive impulsive (e.g., seismic airguns, impact pile 
driving) 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

[[Page 22423]]

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.
    ADOT&PF's proposed activity includes the use of continuous 
(vibratory pile driving and removal) and impulsive (impact pile 
driving) sources, and therefore the RMS SPL thresholds of 120 and 160 
dB re 1 [mu]Pa 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). ADOT&PF's 
proposed activity includes the use of impulsive (impact pile driving) 
and non-impulsive (vibratory pile driving and removal) 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: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                                Table 4--Onset of Permanent Threshold Shift (PTS)
                                                   [NMFS 2018]
----------------------------------------------------------------------------------------------------------------
                                                         PTS onset thresholds * (received level)
             Hearing group             -------------------------------------------------------------------------
                                                Impulsive                          Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans..........  Cell 1: L0-pk,flat: 219    Cell 2: LE,, LF,24h: 199 dB.
                                         dB; LE, LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans..........  Cell 3: L0-pk,flat: 230    Cell 4: LE,, MF,24h: 198 dB.
                                         dB; LE, MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.........  Cell 5: L0-pk,flat: 202    Cell 6: LE,, HF,24h: 173 dB.
                                         dB; LE,,HF,24h: 155 dB.
Phocid Pinnipeds (PW)(Underwater).....  Cell 7: L0-pk.flat: 218    Cell 8: LE,PW,24h: 201 dB.
                                         dB; LE,,PW,24h: 185 dB.
Otariid Pinnipeds (OW)(Underwater)....  Cell 9: L0-pk,flat: 232    Cell 10: LE,OW,24h: 219 dB.
                                         dB; LE,,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric 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 are recommended for consideration.
Note: Peak sound pressure level (L0-pk) has a reference value of 1 [mu]Pa, and weighted cumulative sound
  exposure level (LE,) has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to be
  more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
  is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
  hearing range of marine mammals (i.e., 7 Hz to 160 kHz). 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 weighted
  cumulative sound exposure level thresholds could be exceeded in a multitude of ways (i.e., varying exposure
  levels and durations, duty cycle). When possible, it is valuable for action proponents to indicate the
  conditions under which these thresholds will be exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that are used in estimating the area ensonified above the 
acoustic thresholds, including source levels and transmission loss 
coefficient.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., impact pile driving, vibratory 
pile driving and removal). The maximum (underwater) area ensonified 
above the thresholds for behavioral harassment referenced above is 
11.49 km\2\ (7.14 mi\2\), and is governed by the topography of Auke Bay 
and the various islands located within and around the bay. The eastern 
part of Auke Bay is acoustically shadowed by Auke Cape. Coghlan Island, 
and Suedla Island, and would inhibit sound transmission from reaching 
the more open waters toward Spuhn Island (see Figure 6-2 in the IHA 
application). Additionally, vessel traffic and other commercial and 
industrial activities in the project area may contribute to elevated 
background noise levels which may mask sounds produced by the project.
    Transmission loss (TL) is the decrease in acoustic intensity as an 
acoustic pressure wave propagates out from a source. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. The general formula for underwater TL is:

TL = B * Log10 (R1/R2),

where

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

    This formula neglects loss due to scattering and absorption, which 
is assumed to be zero here. The degree to which underwater sound 
propagates away from a sound source is dependent on a variety of 
factors, most notably the water bathymetry and presence or absence of 
reflective or absorptive conditions including in-water structures and 
sediments. Spherical spreading occurs in a perfectly unobstructed 
(free-field) environment not limited by depth or water surface, 
resulting in a 6 dB reduction in sound level for each doubling of 
distance from the source (20*log[range]). Cylindrical spreading occurs 
in an environment in which sound propagation is bounded by the water 
surface and sea bottom, resulting in a reduction of 3 dB in sound level 
for each doubling of distance from the source (10*log[range]). A 
practical spreading value of 15 is often used under conditions, such as 
the project site, where water increases with depth as the receiver 
moves away from the shoreline, resulting in an expected propagation 
environment that would lie between spherical and cylindrical spreading 
loss conditions. Practical spreading loss is assumed here.
    The intensity of pile driving sounds is greatly influenced by 
factors such as the type of piles, hammers, and the physical 
environment in which the activity takes place. In order to calculate 
the distances to the Level A harassment and the Level B harassment 
sound thresholds for the methods and piles being used in this

[[Page 22424]]

project, NMFS used acoustic monitoring data from other locations to 
develop proxy source levels for the various pile types, sizes and 
methods. The project includes vibratory and impact pile installation of 
steel pipe piles and vibratory removal of steel pipe piles. Source 
levels for each pile size and driving method are presented in Table 5. 
The source levels for vibratory and impact installation of all pile 
sizes are based on the averaged source level of the same type of pile 
reported by California Department of Transportation (Caltrans) in pile 
driving source level compendium documents (Caltrans, 2015 and 2020).

                                          Table 5--Proxy Sound Source Levels for Pile Sizes and Driving Methods
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Proxy source level
                                                              ------------------------------------------------
              Pile size                        Method             dB RMS re       dB SEL re      dB peak re                Literature source
                                                                   1[mu]Pa      1[mu]Pa\2\sec      1[mu]Pa
--------------------------------------------------------------------------------------------------------------------------------------------------------
30 in...............................  Vibratory..............             159             N/A             N/A  Caltrans 2020.
24 in...............................  Vibratory..............             154             N/A             N/A  Caltrans 2020.
18 in...............................  Vibratory..............             158             N/A             N/A  Caltrans 2020.
30 in...............................  Impact.................             190             177             210  Caltrans 2015, 2020.
24 in...............................  Impact.................             190             177             203  Caltrans 2015, 2020.
18 in...............................  Impact.................             185             175             200  Caltrans 2015, 2020.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    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 impact or vibratory pile driving and 
removal, 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 (Table 6), and the resulting estimated 
isopleths and the calculated Level B harassment isopleth (Table 7), are 
reported below. For source levels of each pile please refer to Table 5.
    For impact installation of piles the harassment zones were 
calculated based on the number of piles to be installed per day. 
ADOT&PF provided a range of one to four piles per day for impact 
instillation for all pile sizes. This was done to account for more 
efficient days of pile installation as not to limit construction 
activity on those days. If more piles per day are installed it is 
likely to reduce the number of days impact installation would occur.

          Table 6--User Spreadsheet Input Parameters Used for Calculating Level A Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
                                                               Weighting
                                                                 factor     Number of    Number of     Activity
  Pile size and installation method    Spreadsheet tab used    adjustment  strikes per   piles per     duration
                                                                 (kHz)         pile         day       (minutes)
----------------------------------------------------------------------------------------------------------------
30 in vibratory installation........  A.1 Vibratory pile              2.5          N/A            3           60
                                       driving.
24 in vibratory installation........  A.1 Vibratory pile              2.5          N/A            3           60
                                       driving.
24 in vibratory installation          A.1 Vibratory pile              2.5          N/A            3           30
 (temporary).                          driving.
24 in vibratory removal (temporary).  A.1 Vibratory pile              2.5          N/A            3           60
                                       driving.
18 in vibratory installation........  A.1 Vibratory pile              2.5          N/A            3           60
                                       driving.
18 in vibratory removal (existing)..  A.1 Vibratory pile              2.5          N/A            3           30
                                       driving.
30 in impact installation...........  E.1 Impact pile                   2        1,000          1-4          N/A
                                       driving.
24 in impact installation...........  E.1 Impact pile                   2        1,000          1-4          N/A
                                       driving.
24 in impact installation...........  E.1 Impact pile                   2          500          1-4          N/A
                                       driving.
18 in impact installation...........  E.1 Impact pile                   2          800          1-4          N/A
                                       driving.
----------------------------------------------------------------------------------------------------------------


                          Table 7-- Calculated Level A and Level B Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
                                                          Level A harassment zone (m)
                                           ---------------------------------------------------------   Level B
                 Activity                       LF-         MF-         HF-                           harassment
                                             cetaceans   cetaceans   cetaceans   Phocids   Otariids    zone (m)
----------------------------------------------------------------------------------------------------------------
30 in vibratory installation..............          11           1          16         7          1        3,981
24 in vibratory installation..............           5           1           8         3          1        1,848
24 in vibratory installation (temporary)..           4           1           5         2          1  ...........
18 in vibratory installation..............           9           1          14         6          1  ...........
24 in vibratory removal (temporary).......           5           1           8         3          1  ...........
18 in vibratory removal (existing)........           9           1          14         6          1  ...........
30 in impact installation (4 piles per           1,002          36       1,194       537         39        1,000
 day; 1,000 strikes per pile).............
30 in impact installation (3 piles per             827          30         985       443         33  ...........
 day; 1,000 strikes per pile).............
30 in impact installation (2 piles per             632          23         752       338         25  ...........
 day; 1,000 strikes per pile).............

[[Page 22425]]

 
30 in impact installation (1 pile per day;         398          15         474       213         16
 1,000 strikes per pile)..................
24 in impact installation (4 piles per           1,002          36       1,194       537         39        1,000
 day; 1,000 strikes per pile).............
24 in impact installation (3 piles per             827          30         985       443         33  ...........
 day; 1,000 strikes per pile).............
24 in impact installation (2 piles per             632          23         752       338         25  ...........
 day; 1,000 strikes per pile).............
24 in impact installation (1 pile per day;         398          15         474       213         16  ...........
 1,000 strikes per pile)..................
24 in impact installation (4 piles per             632          23         752       338         25  ...........
 day; 500 strikes per pile)...............
24 in impact installation (3 piles per             521          19         621       279         21  ...........
 day; 500 strikes per pile)...............
24 in impact installation (2 piles per             398          15         474       213         16  ...........
 day; 500 strikes per pile)...............
24 in impact installation (1 pile per day;         251           9         299       134         10  ...........
 500 strikes per pile)....................
18 in impact installation (4 piles per             636          23         757       340         25          464
 day; 800 strikes per pile)...............
18 in impact installation (3 piles per             525          19         625       281         21  ...........
 day; 800 strikes per pile)...............
18 in impact installation (2 piles per             401          15         477       215         16  ...........
 day; 800 strikes per pile)...............
18 in impact installation (1 pile per day;         252           9         301       135         10  ...........
 800 strikes per pile)....................
----------------------------------------------------------------------------------------------------------------

Marine Mammal Occurrence and Take Estimation

    In this section, we provide information about the occurrence of 
marine mammals, including density or other relevant information that 
would inform the take calculations.
    When available, peer-reviewed scientific publications were used to 
estimate marine mammal abundance in the project area. Data from 
monitoring reports from previous projects on the Auke Bay Ferry 
Terminal were used as well as reports from other projects in Juneau, 
Alaska. However, scientific surveys and resulting data, such as 
population estimates, densities, and other quantitative information, 
are lacking for some marine mammal populations and most areas of 
southeast Alaska, including Auke Bay. Therefore, AKDOT&PF gathered 
qualitative information from discussions with knowledgeable local 
people in the Auke Bay area.
    Here 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. Since reliable densities are 
not available, the applicant requests take based on the maximum number 
of animals that may occur in the harbor in a specified measure of time 
multiplied by the total duration of the activity.
Humpback Whale
    Use of Auke Bay by humpback whales is intermittent and irregular 
year-round. During winter, researchers have documented 1 to 19 
individual humpback whales per month in waters close to the project 
area, including Lynn Canal (Moran et al., 2018a; Straley et al., 2018). 
Group sizes in southeast Alaska generally range from one to four 
individuals (Dahlheim et al., 2009). Based on this, we predict that two 
groups of two humpback whales could be exposed to Level B harassment 
during each day of the 61 days of work for a total of 244 animals. As 
described previously, 2.4 percent of the humpback whales in Southeast 
Alaska are members of the Mexico DPS, and therefore six animals would 
be Mexico DPS individuals and the remaining 238 animals would be Hawaii 
DPS individuals.
    The largest Level A shutdown zone for humpback whales extends 1,002 
meters from the noise source (Table 7), and would occur only on days 
when impact driving of four piles is expected. All construction work 
would be shut down prior to a humpback whale entering the Level A zone 
specific to the in-water activity underway at the time. No take by 
Level A harassment is proposed or requested for humpback whales.
Minke Whales
    Dedicated surveys for cetaceans in southeast Alaska found that 
minke whales were scattered throughout inland waters from Glacier Bay 
and Icy Strait to Clarence Strait, with small concentrations near the 
entrance of Glacier Bay. All sightings were of single minke whales, 
except for a single sighting of multiple minke whales. Surveys took 
place in spring, summer, and fall, and minke whales were present in low 
numbers in all seasons and years (Dahlheim et al., 2009). Although 
minke whales are rarely occur in the project area we are conservatively 
proposing to authorize take of one minke whale per month by Level B 
harassment.
    The Level A harassment zones for minke whales are the same as for 
humpback whales, and the shutdown protocols would be the same as well. 
Therefore, given the low occurrence of minke whales combined with the 
mitigation, takes by Level A harassment have not been requested and are 
not proposed to be authorized.
Killer Whale
    Killer whales are observed occasionally during summer throughout 
Lynn Canal, but their presence in Auke Bay is unlikely. As a 
precaution, because Level B harassment zones extend beyond Auke Bay, 
ADOT&PF requests take by Level B harassment for one killer whale 
resident pod and one transient pod. Groups from those pods are likely 
to be 14 animals and 44 animals, respectively (Dahlheim et al., 2009). 
ADOT&PF would implement shutdown zones that encompass the largest Level 
A harassment zones for killer whales during all pile driving 
activities. Killer whales are generally conspicuous and PSOs are 
expected to detect killer whales and implement a shutdown before the 
animals enter the Level A harassment zone. Therefore, takes by Level A 
harassment have not been requested and are not proposed to be 
authorized.
Pacific White-Sided Dolphins
    Based on occurrence data ADOT&PF requested a total of 92 takes by 
Level B harassment (the median group size observed in aerial surveys; 
range from 20 to 164 individuals) (Muto et al. 2022). NMFS concurs and 
has proposed authorization of Level B harassment of one group of 
Pacific white-sided dolphins to occur over the duration of the project. 
The largest Level A harassment zone for Pacific white-sided dolphins 
extends 36 m from the source during impact installation of 30-in piles 
(Table 7). Pacific white-sided dolphins are expected to be seen by PSOs 
before entering this zone and shutdown of activity would occur. No take 
by Level

[[Page 22426]]

A harassment is proposed or anticipated.
Harbor Porpoise
    Initially ADOT&PF requested a total of 122 takes of harbor porpoise 
over the course of the 61 day project. ADOT&PF estimated that 25 
percent of those takes could be Level A exposures which would equate to 
30 over the project duration. After further review of current and 
previous monitoring results, including unpublished data (Wright, S., 
pers. comm.), that showed higher numbers of harbor porpoises in the 
area, we recommended four animals per day equating to 244 takes of 
harbor porpoise by Level A and Level B harassment. NMFS predicts that 
up to 25 percent of the total exposures could result in take by Level A 
harassment for a total of 61. The remaining 183 takes would be by Level 
B harassment.
    Harbor porpoises are known to be an inconspicuous species and are 
challenging for protected species observers (PSOs) to sight, making any 
approach to a specific area potentially difficult to detect. Because 
harbor porpoises move quickly and elusively, it is possible that they 
may enter the Level A harassment zone without detection. The largest 
Level A harassment zone results from impact driving of 30-in piles, and 
extends 1,194 m from the source for high frequency cetaceans (Table 7). 
ADOT&PF would implement a shutdown zone for harbor porpoises that 
encompasses the largest Level A harassment zone (see Proposed 
Mitigation section) but given the sighting challenges for PSOs some 
take by Level A harassment is expected.
Dall's Porpoise
    No systematic studies of Dall's porpoise abundance or distribution 
have occurred in Auke Bay; however, Dall's porpoises have been 
consistently observed in Lynn Canal, Stephens Passage, upper Chatham 
Strait, Frederick Sound, and Clarence Strait (Dalheim et al., 2000). 
ADOT&PF initially requested take of one group of 20 animals per month 
in the project area for a total of 80 takes by Level B harassment. 
After reviewing ADOT&PF's monitoring results from Auke Bay one lone 
Dall's porpoise was sighted. Thus, we proposed a conservative estimate 
of two groups of five animals per month. This would result in a maximum 
of 30 takes by Level B harassment throughout the course of the project.
    ADOT&PF would implement shutdown zones for porpoises that encompass 
the largest Level A harassment zones for each pile driving activity 
(see Proposed Mitigation section). The largest Level A harassment zone 
for Dall's porpoise extends 1,194 m from the source during impact 
installation of 30-in piles (Table 7). Given the more conspicuous 
rooster-tail generated by swimming Dall's porpoises, which makes them 
more noticeable than harbor porpoises, PSOs are expected to detect 
Dall's porpoises prior to them entering the Level A harassment zone 
(Jefferson 2009). Therefore, takes of Dall's porpoises by Level A 
harassment have not been requested and are not proposed to be 
authorized.
Steller Sea Lion
    Based on recent monitoring reports for Auke Bay Ferry Terminal and 
Statter Harbor projects it is estimated that groups of up to 50 animals 
per day could be exposed to underwater noise. A total of 3,050 
exposures to sound levels at or above the Level B harassment threshold 
could occur over the 61 days of construction. Given the 1.4 percent of 
Steller sea lions belong to the wDPS in Auke Bay, 43 total exposures 
are expected from the wDPS and the remaining 3,008 exposures of eDPS 
Steller sea lions.
    The largest Level A harassment zone for otariid pinnipeds extends 
39 m from the source (Table 7). ADOT&PF is planning to implement a 
larger shutdown zones than the Level A harassment zones during all pile 
installation and removal activities (see Proposed Mitigation section), 
which is expected to eliminate the potential for take by Level A 
harassment of Steller sea lions. Therefore, no takes of Steller sea 
lions by Level A harassment were requested or are proposed to be 
authorized.

California Sea Lion

    California sea lions rarely occur in the project area. In 2017, a 
lone California sea lion was spotted in the harbor. Recently, 
monitoring reports from similar construction projects did not observe 
any California sea lions in Auke Bay. Based on the sighting from 2017, 
ADOT&PF is estimating one animal per day of construction which would 
equate to 61 takes by Level B harassment.
    Similar to Steller sea lions, the largest Level A harassment zone 
for otariid pinnipeds extends 39 m from the source (Table 7). ADOT&PF 
is planning to implement larger shutdown zones than the Level A 
harassment zones during all pile installation and removal activities 
(see Proposed Mitigation section), which is expected to eliminate the 
potential for take by Level A harassment of California sea lions. 
Therefore, no takes of California sea lions by Level A harassment were 
requested or are proposed to be authorized.

Northern Fur Seal

    Although take of Northern fur seal was not requested by ADOT&PF, 
the NMFS Alaska Regional Office recommended the inclusion of Northern 
fur seals in the take estimation. We estimate that five northern fur 
seals may be present in the action area per month which would result in 
15 takes by Level B harassment over the course of the project.
    The largest Level A harassment zone for otariid pinnipeds extends 
39 m from the source (Table 7). ADOT&PF is planning to implement larger 
shutdown zones than the Level A harassment zones during all pile 
installation and removal activities (see Proposed Mitigation section), 
which is expected to eliminate the potential for take by Level A 
harassment of Northern fur seals. Therefore, no takes of Northern fur 
seals by Level A harassment were requested or are proposed to be 
authorized.

Harbor Seal

    Based on monitoring results of ADOT&PF's 2021 project in Auke Bay 
it is expected that 50 harbor seals per day could be taken during the 
61 days of construction (AKDOT&PF, 2021). This would equate to 3,050 
takes of harbor seals by Level B harassment during the duration of the 
project.
    The largest Level A harassment zone for phocid pinnipeds results 
from impact pile driving of 30-in piles and extends 537 m from the 
source (Table 7). There are no haulouts located within the Level A 
harassment zone and although it is unlikely that harbor seals would 
enter this area without detection while pile driving activities are 
underway, it is possible that harbor seals may approach and enter the 
Level A harassment zone undetected. Two harbor seals are estimated to 
approach the site within 537 m of the source each day. Impact pile 
driving may occur on up to 34 days (Table 1). For this reason, we 
propose take by Level A harassment of two harbor seals daily on the 34 
days of impact pile driving for a total of 68 takes by Level A 
harassment. The largest Level A harassment zone for phocid pinnipeds 
from vibratory pile driving extends 30 m from the source (Table 7). 
ADOT&PF is planning to implement larger shutdown zones than the Level A 
harassment zones during all pile installation and removal activities 
(see Proposed Mitigation section), which is expected to eliminate the 
potential for

[[Page 22427]]

Level A harassment of harbor seals from vibratory pile driving.

Northern Elephant Seal

    Given the increase in population size and sightings throughout 
Southeast Alaska ADOT&PF requested one elephant seal take per week. The 
project is expected to take up to 16 weeks to complete which would 
equate to 16 takes by Level B harassment.
    The largest Level A harassment zone for phocid pinnipeds extends 
537 m from the source (Table 7). ADOT&PF is planning to implement 
larger shutdown zones than the Level A harassment zones during all pile 
installation and removal activities (see Proposed Mitigation section), 
which is expected to eliminate the potential for take by Level A 
harassment of elephant seals. Therefore, no takes of elephant seals by 
Level A harassment were requested or are proposed to be authorized.

                 Table 8--Estimated Take by Level A and Level B Harassment, by Species and Stock
----------------------------------------------------------------------------------------------------------------
                                                                                                       Proposed
                                                           Stock                            Total      take as
           Common name                   Stock         abundance \a\   Level A   Level B   proposed   percentage
                                                                                             take      of stock
----------------------------------------------------------------------------------------------------------------
Humpback whale..................  Central North               10,103         0   \b\ 244        244          2.4
                                   Pacific.
Minke whale.....................  Alaska............             N/A         0         4          4          N/A
Killer Whale....................  Alaska Resident...           1,920         0        41         41          2.1
                                  West Coast                     349         0        14         14          4.0
                                   Transient.
Pacific white-sided dolphin.....  North Pacific.....         931,000         0        92         92        <0.01
Harbor porpoise.................  Southern Southeast             890        61       183        244         27.4
                                   Alaska Inland
                                   Waters.
Dall's porpoise.................  Alaska............          83,400         0        30         30         0.03
Steller sea lion................  Eastern U.S.......          43,201         0     3,008      3,008          6.9
                                  Western U.S.......          52,932         0        43         43         0.08
California sea lion.............  U.S...............         257,606         0        61         61         0.02
Northern fur seal...............  Eastern Pacific...         626,618         0        15         15        <0.01
Harbor seal.....................  Lynn Canal/                 13,388        68     2,982      3,050         22.8
                                   Stephens Passage.
Northern Elephant Seal..........  California........         187,386         0        16         16        <0.01
----------------------------------------------------------------------------------------------------------------
\a\ Stock or DPS size is Nbest according to NMFS 2022 Draft Stock Assessment Reports.
\b\ For ESA section 7 consultation purposes, 2.4 percent are designated to the Mexico DPS and the remaining are
  designated to the Hawaii DPS; therefore, we assigned 6 takes by Level B harassment to the Mexico DPS.

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. 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. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure would 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, impact on 
operations.
    In addition to the measures described later in this section, 
ADOT&PF would employ the following standard mitigation measures:
     At the start of each day, the Contractor(s) would hold a 
briefing with the Lead PSO to outline the activities planned for that 
day.
     If poor weather conditions restrict the PSO's ability to 
make observations within the Level A and B harassment zone of pile 
driving (e.g., if there is excessive wind or fog), pile installation 
and removal would be halted.
    The following measures would apply to ADOT&PF's mitigation 
requirements:
    Implementation of Shutdown Zones for Level A Harassment--For all 
pile driving/removal activities, ADOT&PF would implement shutdowns 
within designated zones. The purpose of a shutdown zone is generally to 
define an area within which shutdown of activity would occur upon 
sighting of a marine mammal (or in anticipation of an animal entering 
the defined area). Implementation of shutdowns would be used to avoid 
or minimize incidental Level A harassment exposures from vibratory and 
impact pile driving for all 11 species for which take may occur (see 
Table 8). ADOT&PF has voluntarily implemented a minimum shutdown zone 
of 30 m during all pile driving and removal activities (Table 9). 
Shutdown zones for impact pile driving activities are based on the 
Level A harassment zones and therefore vary by pile size, number of 
piles installed per day, and marine mammal hearing group (Table 9). 
Shutdown zones for impact pile driving would be established each day 
for the greatest number of piles that are expected to be installed that 
day. The placement of PSOs during all pile driving activities 
(described in detail in the Monitoring and Reporting section) would 
ensure the full extent of shutdown zones are visible to PSOs.

[[Page 22428]]



                          Table 9--Shutdown Zones During Pile Installation and Removal
----------------------------------------------------------------------------------------------------------------
                                                                            Shutdown zones (m)
                                              Piles per --------------------------------------------------------
                  Activity                      day *        LF          MF          HF
                                                          cetaceans   cetaceans   cetaceans   Phocids   Otariids
----------------------------------------------------------------------------------------------------------------
All vibratory installation and removal.....                                   30
----------------------------------------------------------------------------------------------------------------
30-in impact (1,000 strikes)...............           4       1,100          40       1,200       540         40
                                                      3         830          30         990       450  .........
                                                      2         640                     760       340         30
                                                      1         400                     480       220
----------------------------------------------------------------------------------------------------------------
24-in impact (1,000 strikes)...............           4       1,100          40       1,200       540         40
                                                      3         830          30         990       450         30
                                                      2         640  ..........         760       340
                                                      1         400  ..........         480       220
----------------------------------------------------------------------------------------------------------------
24-in impact (500 strikes).................           4         640          30         760       340         30
                                                      3         530                     630       280
                                                      2         400                     480       220
                                                      1         260                     300       140
----------------------------------------------------------------------------------------------------------------
18-in impact (800 strikes).................           4         640          30         760       340         30
                                                      3         530                     630       280
                                                      2         400                     480       220
                                                      1         260                     300       140
----------------------------------------------------------------------------------------------------------------
* The applicant would chose the number of piles to be driven in any given day before work begins

    Establishment of Monitoring Zones--ADOT&PF has identified 
monitoring zones correlated with the larger of the Level B harassment 
or Level A harassment zones. Monitoring zones provide utility for 
observing by establishing monitoring protocols for areas adjacent to 
the shutdown zones. Monitoring zones enable observers to be aware of 
and communicate the presence of marine mammals in the project area 
outside the shutdown zone and thus prepare for a potential cease of 
activity should the animal enter the shutdown zone. PSOs would monitor 
the entire visible area to maintain the best sense of where animals are 
moving relative to the zone boundaries defined in Tables 9 and 10. 
Placement of PSOs on the shorelines around Auke Bay allow PSOs to 
observe marine mammals within and near Auke Bay.

                 Table 10--Marine Mammal Monitoring Zone
------------------------------------------------------------------------
                                                        Monitoring zone
                       Activity                               (m)
------------------------------------------------------------------------
30-in vibratory installation.........................              3,981
24-in and 18-in vibratory installation and removal...              1,848
30-in and 24 in impact installation..................              1,200
18-in impact installation............................                760
------------------------------------------------------------------------

    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 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.
    Pre-Activity Monitoring--Prior to the start of daily in-water 
construction activity, or whenever a break in pile driving/removal of 
30 minutes or longer occurs, PSOs would observe the shutdown and 
monitoring zones for a period of 30 minutes. The shutdown zone would be 
considered cleared when a marine mammal has not been observed within 
the zone for that 30-minute period. If a marine mammal is observed 
within the shutdown zone, a soft-start cannot proceed until the animal 
has left the zone or has not been observed for 15 minutes. If the 
monitoring zone has been observed for 30 minutes and marine mammals are 
not present within the zone, soft-start procedures can commence and 
work can continue even if visibility becomes impaired within the 
monitoring zone. When a marine mammal permitted for take by Level B 
harassment is present in the Level B harassment zone, activities may 
begin. No work may begin unless the entire shutdown zone is visible to 
the PSOs. If work ceases for more than 30 minutes, the pre-activity 
monitoring of both the monitoring zone and shutdown zone would 
commence.
    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least practicable impact on the 
affected species or stocks and their habitat, paying particular 
attention to rookeries,

[[Page 22429]]

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 would result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present while 
conducting the activities. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
     Mitigation and monitoring effectiveness.

Visual Monitoring

    Monitoring shall be conducted by NMFS-approved observers in 
accordance with the monitoring plan and section 5 of the IHA. Trained 
observers shall be placed from the best vantage point(s) practicable to 
monitor for marine mammals and implement shutdown or delay procedures 
when applicable through communication with the equipment operator. 
Observer training must be provided prior to project start, and shall 
include instruction on species identification (sufficient to 
distinguish the species in the project area), description and 
categorization of observed behaviors and interpretation of behaviors 
that may be construed as being reactions to the specified activity, 
proper completion of data forms, and other basic components of 
biological monitoring, including tracking of observed animals or groups 
of animals such that repeat sound exposures may be attributed to 
individuals (to the extent possible).
    Monitoring would be conducted 30 minutes before, during, and 30 
minutes after pile driving/removal activities. In addition, observers 
shall record all incidents of marine mammal occurrence, regardless of 
distance from activity, and shall document any behavioral reactions in 
concert with distance from piles being driven or removed. Pile driving/
removal 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.
    A minimum of two PSOs would be on duty during all impact 
installation and a minimum of three MMOs during vibratory installation/
removal. Locations from which MMOs would be able to monitor for marine 
mammals are readily available from publicly accessible shoreside areas 
at the Auke Bay East Ferry Terminal and, if necessary, other public and 
private points along the Glacier and Douglas highways. Monitoring 
locations would be selected by the Contractor during pre-construction. 
PSOs would monitor for marine mammals entering the Level B harassment 
zones; the position(s) may vary based on construction activity and 
location of piles or equipment.
    PSOs would scan the waters using binoculars, and/or spotting 
scopes, and would use a handheld range-finder device to verify the 
distance to each sighting from the project site. All PSOs would be 
trained in marine mammal identification and behaviors and are required 
to have no other project-related tasks while conducting monitoring. In 
addition, monitoring would be conducted by qualified observers, who 
would be placed at the best vantage point(s) practicable to monitor for 
marine mammals and implement shutdown/delay procedures when applicable 
by calling for the shutdown to the hammer operator via a radio. ADOT&PF 
would adhere to the following observer qualifications:
    (i) Independent observers (i.e., not construction personnel) are 
required;
    (ii) One PSO would be designated as the lead PSO or monitoring 
coordinator and that observer must have prior experience working as an 
observer;
    (iii) Other observers may substitute education (degree in 
biological science or related field) or training for experience; and
    (iv) ADOT&PF must submit observer Curriculum Vitaes for approval by 
NMFS.
    Additional standard observer qualifications include:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates and times when in-water construction 
activities were suspended to avoid potential incidental injury from 
construction sound of marine mammals observed within a defined shutdown 
zone; and marine mammal behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.

Reporting

    A draft marine mammal monitoring report would be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities. It would include an overall description of work completed, 
a narrative regarding marine mammal sightings, and associated PSO data 
sheets. Specifically, the report must include:
     Dates and times (begin and end) of all marine mammal 
monitoring.
     Construction activities occurring during each daily 
observation period, including the number and type of piles driven or 
removed and by what method (i.e., impact driving) and the total 
equipment duration for cutting for each pile or total number of strikes 
for each pile (impact driving).

[[Page 22430]]

     PSO locations during marine mammal monitoring.
     Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
     Upon observation of a marine mammal, the following 
information: Name of PSO who sighted the animal(s) and PSO location and 
activity at time of sighting; Time of sighting; 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; Distance and bearing of each 
marine mammal observed relative to the pile being driven for each 
sighting (if pile driving was occurring at time of sighting); Estimated 
number of animals (min/max/best estimate); Estimated number of animals 
by cohort (adults, juveniles, neonates, group composition, etc.); 
Animal's closest point of approach and estimated time spent within the 
harassment zone; Description of any marine mammal behavioral 
observations (e.g., observed behaviors such as feeding or traveling), 
including an assessment of behavioral responses thought to have 
resulted from the activity (e.g., no response or changes in behavioral 
state such as ceasing feeding, changing direction, flushing, or 
breaching);
     Number of marine mammals detected within the harassment 
zones, by species.
     Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensued, and resulting changes in behavior of the 
animal(s), if any.
    If no comments are received from NMFS within 30 days, the draft 
final report would constitute the final report. If comments are 
received, a final report addressing NMFS comments must be submitted 
within 30 days after receipt of comments.

Reporting Injured or Dead Marine Mammals

    In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA 
(if issued), such as an injury, serious injury or mortality, ADOT&PF 
would immediately cease the specified activities and report the 
incident to the Chief of the Permits and Conservation Division, Office 
of Protected Resources, NMFS, and the Alaska Regional Stranding 
Coordinator. The report would include the following information:
     Description of the incident;
     Environmental conditions (e.g., Beaufort sea state, 
visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities would not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS would work with ADOT&PF to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. ADOT&PF would not be able 
to resume their activities until notified by NMFS via letter, email, or 
telephone.
    In the event that ADOT&PF discovers an injured or dead marine 
mammal, and the lead PSO determines that the cause of the injury or 
death is unknown and the death is relatively recent (e.g., in less than 
a moderate state of decomposition as described in the next paragraph), 
ADOT&PF would immediately report the incident to the Chief of the 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
and the NMFS Alaska Stranding Hotline and/or by email to the Alaska 
Regional Stranding Coordinator. The report would include the same 
information identified in the paragraph above. Activities would be able 
to continue while NMFS reviews the circumstances of the incident. NMFS 
would work with ADOT&PF to determine whether modifications in the 
activities are appropriate.
    In the event that ADOT&PF discovers an injured or dead marine 
mammal and the lead PSO determines that the injury or death is not 
associated with or related to the activities authorized in the IHA 
(e.g., previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), ADOT&PF would report the incident 
to the Chief of the Permits and Conservation Division, Office of 
Protected Resources, NMFS, and the NMFS Alaska Stranding Hotline and/or 
by email to the Alaska Regional Stranding Coordinator, within 24 hours 
of the discovery. ADOT&PF would provide photographs, video footage (if 
available), or other documentation of the stranded animal sighting to 
NMFS and the Marine Mammal Stranding Network.

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 8, 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 removal activities associated with the project as 
outlined previously, have the potential to disturb or displace marine 
mammals. Specifically, the specified activities may result in take, in 
the form of Level A harassment and Level B harassment from underwater 
sounds generated from pile driving and removal. Potential takes could 
occur if individuals of these

[[Page 22431]]

species are present in zones ensonified above the thresholds for Level 
A or Level B harassment identified above when these activities are 
underway.
    Take by Level A and Level B harassment would be due to potential 
behavioral disturbance, TTS, and PTS. No serious injury or mortality is 
anticipated or proposed for authorization given the nature of the 
activity and measures designed to minimize the possibility of injury to 
marine mammals. Take by Level A harassment is only anticipated for 
harbor porpoise and harbor seal. The potential for harassment is 
minimized through the construction method and the implementation of the 
planned mitigation measures (see Proposed Mitigation section).
    Based on reports in the literature as well as monitoring from other 
similar activities, behavioral disturbance (i.e., level B harassment) 
would likely be limited to reactions such as increased swimming speeds, 
increased surfacing time, or decreased foraging (if such activity were 
occurring) (e.g., Thorson and Reyff, 2006; HDR, Inc. 2012; Lerma, 2014; 
ABR, 2016). Most likely for pile driving, individuals would simply move 
away from the sound source and be temporarily displaced from the areas 
of pile driving, although even this reaction has been observed 
primarily only in association with impact pile driving. The pile 
driving activities analyzed here are similar to, or less impactful 
than, numerous other construction activities conducted in southeast 
Alaska, which have taken place with no observed severe responses of any 
individuals or known long-term adverse consequences. Level B harassment 
would be reduced to the level of least practicable adverse impact 
through use of mitigation measures described herein and, if sound 
produced by project activities is sufficiently disturbing, animals are 
likely to simply avoid the area while the activity is occurring. While 
vibratory driving associated with the proposed project may produce 
sound at distances of many kilometers from the project site, thus 
overlapping with some likely less-disturbed habitat, the project site 
itself is located in a busy harbor and the majority of sound fields 
produced by the specified activities are close to the harbor. Animals 
disturbed by project sound would be expected to avoid the area and use 
nearby higher-quality habitats.
    In addition to the expected effects resulting from authorized Level 
B harassment, we anticipate that harbor porpoises and harbor seals may 
sustain some limited Level A harassment in the form of auditory injury. 
However, animals in these locations that experience PTS would likely 
only receive slight PTS, i.e. minor degradation of hearing capabilities 
within regions of hearing that align most completely with the energy 
produced by pile driving, i.e. the low-frequency region below 2 kHz, 
not severe hearing impairment or impairment in the regions of greatest 
hearing sensitivity. If hearing impairment occurs, it is most likely 
that the affected animal would lose a few decibels in its hearing 
sensitivity, which in most cases is not likely to meaningfully affect 
its ability to forage and communicate with conspecifics. As described 
above, we expect that marine mammals would be likely to move away from 
a sound source that represents an aversive stimulus, especially at 
levels that would be expected to result in PTS, given sufficient notice 
through use of soft start.
    The project also is not expected to have significant adverse 
effects on affected marine mammals' habitat. The project activities 
would not modify existing marine mammal habitat for a significant 
amount of time. The activities may cause some fish or invertebrates to 
leave the area of disturbance, thus temporarily impacting marine 
mammals' foraging opportunities in a limited portion of the foraging 
range; but, because of the short duration of the activities, the 
relatively small area of the habitat that may be affected, and the 
availability of nearby habitat of similar or higher value, the impacts 
to marine mammal habitat are not expected to cause significant or long-
term negative consequences.
    Nearly all inland waters of southeast Alaska, including Auke Bay, 
are included in the southeast Alaska humpback whale feeding BIA 
(Ferguson et al., 2015), though humpback whale distribution in 
southeast Alaska varies by season and waterway (Dahlheim et al., 2009). 
Humpback whales are present within Auke Bay intermittently and in low 
numbers. The area of the BIA that may be affected by the proposed 
project is small relative to the overall area of the BIA. The southeast 
Alaska humpback whale feeding BIA is active between March and November 
while the proposed project is scheduled to occur between November and 
March, resulting in only two months of overlap. Additionally, pile 
driving associated with the project is expected to take only 61 days, 
further reducing the temporal overlap with the BIA. Therefore, the 
proposed project is not expected to have significant adverse effects on 
the foraging of Alaska humpback whale. No areas of specific biological 
importance (e.g., ESA critical habitat, other BIAs, or other areas) for 
any other species are known to co-occur with the project area.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect any of the species 
or stocks through effects on annual rates of recruitment or survival:
     No serious injury or mortality is anticipated or proposed 
for authorization;
     Any Level A harassment exposures (i.e., to harbor 
porpoises and harbor seals, only) are anticipated to result in slight 
PTS (i.e., of a few decibels), within the lower frequencies associated 
with pile driving;
     The anticipated incidents of Level B harassment would 
consist of, at worst, temporary modifications in behavior that would 
not result in fitness impacts to individuals;
     The area impacted by the specified activity is very small 
relative to the overall habitat ranges of all species, does not include 
ESA-designated critical habitat, and only temporally overlaps with the 
southeast Alaska humpback whale feeding BIA for two months of the 
planned six months of activity; and
     The proposed mitigation measures are expected to reduce 
the effects of the specified activity to the level of least practicable 
adverse impact.
    In combination, we believe that these factors, as well as the 
available body of evidence from other similar activities, demonstrate 
that the potential effects of the specified activities would have only 
minor, short-term effects on individuals. The specified activities are 
not expected to affect the reproduction or survival of any individual 
marine mammals and, therefore, would not result in impacts on rates of 
recruitment or survival for any species or stock.
    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 would 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

[[Page 22432]]

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.
    Table 8 demonstrates the number of animals that could be exposed to 
received noise levels that could cause Level A and Level B harassment 
for the proposed work in Auke Bay. Our analysis shows that less than 28 
percent of each affected stock could be taken by harassment. The 
numbers of animals proposed to be taken for these stocks would be 
considered small relative to the relevant stock's abundances, even if 
each estimated taking occurred to a new individual--an extremely 
unlikely scenario.
    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 would not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity: (1) 
That is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    The proposed project is not known to occur in an important 
subsistence hunting area. It is a developed area with regular marine 
vessel traffic. However, ADOT&PF plans to provide advanced public 
notice of construction activities to reduce construction impacts on 
local residents, ferry travelers, adjacent businesses, and other users 
of the Auke Bay ferry terminal and nearby areas. This would include 
notification to local Alaska Native tribes that may have members who 
hunt marine mammals for subsistence. Of the marine mammals considered 
in this IHA application, only harbor seals are known to be used for 
subsistence in the project area. If any tribes express concerns 
regarding project impacts to subsistence hunting of marine mammals, 
further communication between would take place, including provision of 
any project information, and clarification of any mitigation and 
minimization measures that may reduce potential impacts to marine 
mammals.
    Based on the description of the specified activity, the measures 
described to minimize adverse effects on the availability of marine 
mammals for subsistence purposes, and the proposed mitigation and 
monitoring measures, NMFS has preliminarily determined that there would 
not be an unmitigable adverse impact on subsistence uses from ADOT&PF's 
proposed activities.

Endangered Species Act

    Section 7(a)(2) of the Endangered Species Act of 1973 (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 wDPS Steller sea lions and 
Mexico DPS humpback whales, which are listed under the ESA.
    The Permits and Conservation Division has requested initiation of 
section 7 consultation with the Alaska Region for the issuance of this 
IHA. NMFS would 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 ADOT&PF for conducting pile installation and removal 
activities at the Auke Bay East ferry terminal between October 1, 2023 
and September 30, 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/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this notice of proposed IHA for the proposed 
action. 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, one-year 
renewal IHA following notice to the public providing an additional 15 
days for public comments when (1) up to another year of identical or 
nearly identical activities as described in the Description of Proposed 
Activity section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activity section of this 
notice would not be completed by the time the IHA expires and a renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed renewal IHA effective date (recognizing that the 
renewal IHA expiration date cannot extend beyond one year from 
expiration of the initial IHA).
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take).
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
    Upon review of the request for renewal, the status of the affected 
species or stocks, and any other pertinent information, NMFS

[[Page 22433]]

determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures would remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: April 7, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2023-07729 Filed 4-12-23; 8:45 am]
BILLING CODE 3510-22-P