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[Federal Register Volume 90, Number 4 (Tuesday, January 7, 2025)]
[Notices]
[Pages 1084-1104]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-00014]

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XE481]

Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the City of Hoonah's Cargo Dock 
Project, Hoonah, Alaska

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

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

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SUMMARY: NMFS has received a request from the City of Hoonah (Hoonah) 
for authorization to take marine mammals incidental to pile driving and 
removal activities associated with the Hoonah Cargo Dock project in 
Hoonah, Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), 
NMFS is requesting comments on its proposal to issue an incidental 
harassment authorization (IHA) to incidentally take marine mammals 
during the specified activities. NMFS is also requesting comments on a 
possible one-time, 1-year renewal that could be issued under certain 
circumstances and if all requirements are met. 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 February 
6, 2025.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service and should be submitted via email to 
[email protected]. Electronic copies of the application and 
supporting documents, as well as a list of the references cited in this 
document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of problems accessing these documents, 
please call the contact listed below.
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments, including all attachments, must 
not exceed a 25-megabyte file size. All comments received are a part of 
the public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying 
information (e.g., name, address) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information.

FOR FURTHER INFORMATION CONTACT: Rachel Wachtendonk, Office of 
Protected Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are proposed or, if the taking is limited to harassment, a notice of a 
proposed IHA is provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the monitoring and 
reporting of the takings. The definitions of all applicable MMPA 
statutory terms used above are included in the relevant sections below 
and can be found in section 3 of the MMPA (16 U.S.C. 1362) and NMFS 
regulations at 50 CFR 216.103.

National Environmental Policy Act

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

Summary of Request

    May 10, 2024, NMFS received a request from Hoonah for an IHA to 
take marine mammals incidental to pile driving and removal activities 
associated with the Hoonah Cargo Dock project in Hoonah, Alaska. 
Following NMFS' review of the application, Hoonah submitted a revised 
versions on September 10, 2024 and October 15, 2024. The application 
was deemed adequate and complete on October 22, 2024. Hoonah's request 
is for take of 8 species of marine mammals by Level B harassment and, 
for a subset of these species, Level A harassment. Neither Hoonah nor 
NMFS expect serious injury

[[Page 1085]]

or mortality to result from this activity and, therefore, an IHA is 
appropriate.
    NMFS previously issued an IHA to Hoonah for the Hoonah Cargo Dock 
project (86 FR 27410, May 20, 2021), and later changed the effective 
dates of the IHA in a re-issuance (87 FR 27571, May 9, 2022). However, 
due to COVID and inflation no work under the IHA was conducted. Since 
then, Hoonah has made several changes to their project plan and, 
therefore, a new IHA is appropriate.

Description of Proposed Activity

Overview

    Hoonah is proposing to install a cargo dock at the Hoonah Marine 
Industrial Center (HMIC) in Hoonah, Alaska (figure 1). The purpose of 
this project is to install a dock that will enable barges to land, 
unload, and load during all tidal conditions and seasons. The project 
is needed to allow for the safe, reliable, and economical transport of 
freight to and from Hoonah, which is only accessible by air and sea. 
The construction of the sheet pile cargo dock, barge ramp, and 
breasting dolphins will require impact and vibratory pile installation 
and down-the-hole (DTH) drilling (referred to as tension anchoring).
    Sounds resulting from pile driving, pile removal, and tension 
anchoring may result in the incidental take of marine mammals by Level 
A and Level B harassment in the form of auditory injury or behavioral 
harassment. Underwater sound would be constrained to Port Fredrick and 
would be truncated by land masses in the inlet. Construction activities 
would start in September 2025 and last 5 months.

Dates and Duration

    The proposed IHA would be effective from September 1, 2025 through 
August 31, 2026. Vibratory and impact pile driving and tension 
anchoring are expected to start in September 2025 and take 107 days 
over a span of 5 months. All pile driving and removal would be 
completed during daylight hours.

Specific Geographic Region

    The project would take place at the HMIC in Hoonah, Alaska, which 
is located within Port Fredrick on Icy Strait. The proposed dock would 
be constructed at an existing barge ramp, adjacent to the Hoonah ferry 
terminal and tank farm.
[GRAPHIC] [TIFF OMITTED] TN07JA25.050

Detailed Description of the Specified Activity

    The construction of the sheet pile cargo dock, barge ramp, and 
breasting dolphins will include the installation of 542 (330 linear 
feet (ft), or 100.6 linear meters (m)) steel sheet piles, 5 steel wye 
piles, 1 steel X pile, 3 20-inch (in), or 0.51-m steel fender piles, 2 
16-in (0.41 m) fender piles, 7 H-piles, 4 36-in (0.91 m) steel pipe 
piles, and 6 36-in (0.91 m) steel batter piles. The installation and 
removal of 50 temporary 24-in (0.61 m) steel pipe piles will be 
completed to support the permanent pile installation. Piles will be 
installed with vibratory and impact hammers, and temporary piles will 
be removed with a vibratory hammer. 8-to-10-in (0.20 to 0.25 m) steel 
pipe casings will be placed in each steel pipe/batter piles as tension 
anchors and set with tension anchoring. Table 1 provides a summary of 
the pile driving activities.

                          Table 1--Number and Type of Piles To Be Installed and Removed
----------------------------------------------------------------------------------------------------------------
                                                             Number of                            Piles    Total
              Activity                 Pile type and size      piles            Method           per day   days
----------------------------------------------------------------------------------------------------------------
Installation.......................  24-in temporary steel          50  Vibratory.............         6       9
                                      pipe pile.
                                     Steel sheet pile......        542  ......................        30      19

[[Page 1086]]

 
                                     Steel wye pile........          5  ......................         2       3
                                     Steel X pile..........          1  ......................         1       1
                                     20-in steel fender              3  ......................         3       1
                                      pile.
                                     16-in steel fender              2  ......................         2       1
                                      pile.
                                     Steel H-pile..........          7  ......................         2       4
                                     36-in steel pipe pile.          4  ......................         2       2
                                     36-in steel batter              6  ......................         2       2
                                      pile.
                                     Steel sheet pile......        542  Impact................        15      36
                                     Steel wye pile........          5  ......................         2       3
                                     Steel X pile..........          1  ......................         1       1
                                     20-in steel fender              3  ......................         3       1
                                      pile.
                                     16-in steel fender              2  ......................         2       1
                                      pile.
                                     Steel H-pile..........          7  ......................         2       4
                                     36-in steel pipe pile.          4  ......................         2       2
                                     36-in steel batter              6  ......................         4       2
                                      pile.
                                     8-to-10-in pipe casing         10  Tension Anchoring.....         2       5
                                      drilling.
Removal............................  24-in temporary steel          50  Vibratory.............         6       9
                                      pipe pile.
----------------------------------------------------------------------------------------------------------------

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

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, instead of reprinting the information. Additional 
information regarding population trends and threats may be found in 
NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and 
more general information about these species (e.g., physical and 
behavioral descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
    Table 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 (M/
SI) from anthropogenic sources are included here as gross indicators of 
the status of the species or stocks and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Alaska and Pacific SARs. All values presented in table 2 are 
the most recent available at the time of publication and are available 
online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                            Table 2--Species \1\ 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/
                                                                                                \2\          abundance survey) \3\               SI \4\
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                                                 Order Artiodactyla--Cetacea--Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Family Balaenopteridae (rorquals)
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Humpback Whale......................  Megaptera novaeangliae.  Mainland Mexico--CA/OR/  T, D, Y             3,477 (0.101, 3,185,           43         22
                                                                WA.                                          2018).
                                                               Hawai[revaps]i.........  -, -, N             11,278 (0.56, 7,265,          127      27.09
                                                                                                             2020).
Minke Whale.........................  Balaenoptera             AK.....................  -, -, N             N/A (N/A, N/A, N/A)           UND          0
                                       acutorostrata.                                                        \5\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                  Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Family Delphinidae
--------------------------------------------------------------------------------------------------------------------------------------------------------
Killer whale........................  Orcinus orca...........  Eastern North Pacific    -, -, N             1,920 (N/A, 1,920,             19        1.3
                                                                Alaska Resident.                             2019) \6\.
                                                               Eastern Northern         -, -, N             302 (N/A, 302, 2018)          2.2        0.2
                                                                Pacific Northern                             \6\.
                                                                Resident.
                                                               West Coast Transient...  -, -, N             349 (N/A, 349, 2018)          3.5        0.4
                                                                                                             \7\.

[[Page 1087]]

 
Pacific White-Sided Dolphin.........  Lagenorhynchus           N Pacific..............  -, -, N             26,880 (N/A, N/A,             UND          0
                                       obliquidens.                                                          1990).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Family Phocoenidae (porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dall's Porpoise.....................  Phocoenoides dalli.....  AK.....................  -, -, N             UND (UND, UND, 2015)          UND         37
                                                                                                             \8\.
Harbor Porpoise.....................  Phocoena phocoena......  Northern Southeast       -, -, N             1,619 (0.26, 1,250,            13        5.6
                                                                Alaska Inland Waters                         2019).
                                                                \9\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      Family Otariidae (eared seals and sea lions)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Steller Sea Lion....................  Eumetopias jubatus.....  Western................  E, D, Y             49,837 (N/A, 49,837,          299        267
                                                                                                             2022) \10\.
                                                               Eastern................  -, -, N             36,308 (N/A, 36,308,        2,178       93.2
                                                                                                             2022) \11\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Family Phocidae (earless seals)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor Seal.........................  Phoca vitulina.........  Glacier Bay/Icy Strait.  -, -, N             7,455 (N/A, 6,680,            120        104
                                                                                                             2017).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
  (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/).
\2\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
  designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or
  which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is
  automatically designated under the MMPA as depleted and as a strategic stock.
\3\ NMFS marine mammal SARs online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region.
  CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.
\5\ Reliable population estimates are not available for this stock. Please see Friday et al. (2013) and Zerbini et al. (2006) for additional information
  on numbers of minke whales in Alaska.
\6\ Nest is based upon counts of individuals identified from photo-ID catalogs.
\7\ Nest is based upon count of individuals identified from photo-ID catalogs in analysis of a subset of data from 1958-2018.
\8\ The best available abundance estimate is likely an underestimate for the entire stock because it is based upon a survey that covered only a small
  portion of the stock's range.
\9\ New stock split from Southeast Alaska stock.
\10\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the United
  States only. The overall Nmin is 73,211 and overall PBR is 439.
\11\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the United
  States only.

    As indicated above, all 8 species (with 12 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 project area are included in table 6 of the 
IHA application. While gray whales and sperm whales have been 
documented in the area, the temporal and/or spatial occurrence of these 
species is such that take is not expected to occur, and they are not 
discussed further beyond the explanation provided here. Gray whales are 
considered to be very rare (no local knowledge of sightings in the 
project area) and sperm whales are considered to be rare (no sightings 
in recent years) within the project area.
    Additional information relevant to our analyses (beyond that 
included above, in the application, and on NMFS website) is included 
below, as appropriate. In addition, the Northern sea otter (Enhydra 
lutris kenyoni) may be found in the project area. However, sea otters 
are managed by the U.S. Fish and Wildlife Service and are not 
considered further in this document.

Humpback Whale

    The Mainland Mexico--CA/OR/WA and Hawaii stocks of humpback whale 
occur in the project area. Wild et al. (2023) identified Glacier Bay 
and Icy Strait as a Biologically Important Area (BIA) for humpback 
whales for feeding during the months of May through October, with an 
importance score of two (indicating an area of moderate importance), an 
intensity score of two (indicating an area of moderate comparative 
significance) and a data support score of three (highest relative 
confidence in the available supporting data). Humpback whales have been 
observed within Port Fredrick and Icy Strait, with most sightings 
occurring from late May through October (SolsticeAK 2024).

Steller Sea Lion

    Steller sea lions were listed as threatened range-wide under the 
ESA on November 26, 1990 (55 FR 49204). Steller sea lions were 
subsequently partitioned into the western and eastern Distinct 
Population Segments (DPSs; western and eastern stocks) in 1997 (62 FR 
24345, May 5, 1997). The eastern DPS remained classified as threatened 
until it was delisted in November 2013. The western DPS (those 
individuals west of the 144[deg] W longitude or Cape Suckling, Alaska) 
was upgraded to endangered status following separation of the DPSs, and 
it remains endangered today. There is regular movement of both DPSs 
across this 144[deg] W longitude boundary especially within a core 
mixing zone (Jemison et al., 2013). The proposed project is located 
outside of the known core mixing zone of eastern DPS and western DPS 
Steller sea lions; however, western DPS animals have been recorded 
within the Lynn Canal extended mixing zone which includes the proposed 
project area (Hastings et al., 2020; Jemison et al., 2013). Therefore, 
while both DPSs could be observed within the project area, most are 
expected to be from the unlisted eastern DPS.

[[Page 1088]]

    Steller sea lions do not follow traditional migration patterns, but 
will move from offshore rookeries in the summer to more protected 
haulouts closer to shore in the winter. They use rookeries and haulouts 
as resting spots as they follow prey movements and take foraging trips 
for days, usually within a few miles (mi) of their rookery or haulout. 
They are generalist marine predators and opportunistic feeders based on 
seasonal abundance and location of prey. Steller sea lions forage in 
nearshore as well as offshore areas, following prey resources. They are 
highly social and are often observed in large groups while hauled out 
but alone or in small groups when at sea (NMFS 2023b).
    Steller sea lions are common in the proposed project area and 
reside in the area year-round. The nearest rookery to the proposed 
project is White Sisters (~72 kilometers (km) (44.5 mi southwest of 
project) and the nearest major haulout is The Sisters (13 km (8 mi) 
northeast of project) (AFSC 2023).

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.). Generalized hearing ranges were 
chosen based on the ~65 decibel (dB) threshold from composite 
audiograms, previous analyses in NMFS (2018), and/or data from Southall 
et al. (2007) and Southall et al. (2019). We note that the names of two 
hearing groups and the generalized hearing ranges of all marine mammal 
hearing groups have been recently updated (NMFS 2024) as reflected 
below in in table 3.

                  Table 3--Marine Mammal Hearing Groups
                              [NMFS, 2024a]
------------------------------------------------------------------------
           Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
UNDERWATER:
    Low-frequency (LF) cetaceans     7 Hz to 36 * kHz.
     (baleen whales).
    High-frequency (HF) cetaceans    150 Hz to 160 kHz.
     (dolphins, toothed whales,
     beaked whales, bottlenose
     whales).
    Very High-frequency (VHF)        200 Hz to 165 kHz.
     cetaceans (true porpoises,
     Kogia, river dolphins,
     Cephalorhynchid,
     Lagenorhynchus cruciger & L.
     australis).
    Phocid pinnipeds (PW)            40 Hz to 90 kHz.
     (underwater) (true seals).
    Otariid pinnipeds (OW)           60 Hz to 68 kHz.
     (underwater) (sea lions and
     fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges may not be as broad. Generalized hearing range
  chosen based on ~65 dB threshold from composite audiogram, previous
  analysis in NMFS 2018, and/or data from Southall et al., 2007;
  Southall et al., 2019. Additionally, animals are able to detect very
  loud sounds above and below that ``generalized'' hearing range.

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

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

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

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound is defined as the all-encompassing 
sound in a given place and is usually a composite of sound from many 
sources both near and far. 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 to 20 dB 
from day to day (Richardson et al., 1995). The result is that, 
depending on the source type and its intensity, sound from the 
specified activity may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals.
    In-water construction activities associated with the project would 
include impact pile installation, vibratory pile installation and 
removal, and tension anchoring. Impact hammers typically operate by 
repeatedly dropping and/or pushing a heavy piston onto a pile to drive 
the pile into the substrate. Sound generated by impact hammers is 
impulsive, characterized by rapid rise times and high peak levels, a 
potentially injurious combination

[[Page 1089]]

(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 typically produce less sound (i.e., 
lower levels) than impact hammers. Peak 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; California 
Department of Transportation (CALTRANS), 2015, 2020). Sounds produced 
by vibratory hammers are non-impulsive; the rise time is slower, 
reducing the probability and severity of injury, and the sound energy 
is distributed over a greater amount of time (Nedwell and Edwards, 
2002; Carlson et al., 2005). Tension anchoring through DTH systems 
would also be used during the proposed construction. A DTH hammer is 
essentially a drill bit that drills through the bedrock using a 
rotating function like a normal drill, in concert with a hammering 
mechanism operated by a pneumatic (or sometimes hydraulic) component 
integrated into the DTH hammer to increase speed of progress through 
the substrate (i.e., it is similar to a ``hammer drill'' hand tool). 
The sounds produced by the DTH methods contain both a continuous non-
impulsive component from the drilling action and an impulsive component 
from the hammering effect. Therefore, NMFS treats DTH systems as both 
impulsive and continuous, non-impulsive sound source types 
simultaneously.
    The likely or possible impacts of Hoonah'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 be primarily acoustic in nature.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving is the primary means by which marine 
mammals may be harassed from the proposed 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). In general, exposure to pile driving and 
tension anchoring noise has the potential to result in an auditory 
threshold shift (TS) 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 as an increase in stress 
hormones. Additional noise in a marine mammal's habitat can mask 
acoustic cues used by marine mammals to carry out daily functions such 
as communication and predator and prey detection. The effects of pile 
driving 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 TS as a change, usually an increase, 
in the threshold of audibility at a specified frequency or portion of 
an individual's hearing range above a previously established reference 
level (NMFS, 2018). The amount of TS is customarily expressed in dB. A 
TS can be permanent or temporary. As described in NMFS (2018), there 
are numerous factors to consider when examining the consequence of TS, 
including, but not limited to, the signal temporal pattern (e.g., 
impulsive or non-impulsive), likelihood an individual would be exposed 
for a long enough duration or to a high enough level to induce a TS, 
the magnitude of the TS, time to recovery (seconds to minutes or hours 
to days), the frequency range of the exposure (i.e., spectral content), 
the hearing frequency range of the exposed species relative to the 
signal's frequency spectrum (i.e., how an animal uses sound within the 
frequency band of the signal; e.g., Kastelein et al., 2014), and the 
overlap between the animal and the source (e.g., spatial, temporal, and 
spectral).
    Auditory Injury--NMFS defines auditory injury as damage to the 
inner ear that can result in destruction of tissue . . . which may or 
may not result in permanent threshold shift (PTS; NMFS, 2024a). 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, 
2024a). PTS does not generally affect more than a limited frequency 
range, and an animal that has PTS has incurred some level of hearing 
loss at the relevant frequencies; typically, animals with PTS are not 
functionally deaf (Au and Hastings, 2008; Finneran, 2016). Available 
data from humans and other terrestrial mammals indicate that a 40-dB 
threshold shift approximates PTS onset (see Ward et al., 1958, 1959, 
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 is a temporary, reversible increase 
in the threshold of audibility at a specified frequency or portion of 
an individual's hearing range above a previously established reference 
level (NMFS, 2018). Based on data from cetacean TTS measurements 
(Southall et al., 2007, 2019), a TTS of 6 dB is considered the minimum 
TS clearly larger than any day-to-day or session-to-session variation 
in a subject's normal hearing ability (Schlundt et al., 2000; Finneran 
et al., 2000, 2002). As described in Finneran (2015), marine mammal 
studies have shown the amount of TTS increases with cumulative sound 
exposure level (SELcum) in an accelerating fashion: At low 
exposures with lower SELcum, the amount of TTS is typically 
small and the growth curves have shallow slopes. At exposures with 
higher SELcum, the growth curves become steeper and approach 
linear relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced, TTS can have effects on marine mammals ranging 
from discountable to serious (similar to those discussed in 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 a 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

[[Page 1090]]

exist for coping with this condition to some degree, though likely not 
without cost.
    Many studies have examined noise-induced hearing loss in marine 
mammals (see Finneran (2015) and Southall et al. (2019) for summaries). 
TTS is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter, 2013). While experiencing TTS, the hearing 
threshold rises, and a sound must be at a higher level in order to be 
heard. In terrestrial and marine mammals, TTS can last from minutes or 
hours to days (in cases of strong TTS). In many cases, hearing 
sensitivity recovers rapidly after exposure to the sound ends. For 
pinnipeds in water, measurements of TTS are limited to harbor seals, 
elephant seals (Mirounga angustirostris), bearded seals (Erignathus 
barbatus) and California sea lions (Zalophus californianus) (Kastak et 
al., 1999, 2007; Kastelein et al., 2019a, 2019b, 2021, 2022a, 2022b; 
Reichmuth et al., 2019; Sills et al., 2020). These studies examined 
hearing thresholds measured in marine mammals before and after exposure 
to intense or long-duration sound exposures. The difference between the 
pre-exposure and post-exposure thresholds can be used to determine the 
amount of TS at various post-exposure times.
    The amount and onset of TTS depends on the exposure frequency. 
Sounds at low frequencies, well below the region of best sensitivity 
for a species or hearing group, are less hazardous than those at higher 
frequencies, near the region of best sensitivity (Finneran and 
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are 
higher compared to those in the region of best sensitivity (i.e., a low 
frequency noise would need to be louder to cause TTS onset when TTS 
exposure level is higher), as shown for harbor porpoises and harbor 
seals (Kastelein et al., 2019a, 2019c). Note that in general, harbor 
seals have a lower TTS onset than other measured pinniped species 
(Finneran, 2015). In addition, TTS can accumulate across multiple 
exposures, but the resulting TTS will be less than the TTS from a 
single, continuous exposure with the same SEL (Mooney et al., 2009; 
Finneran et al., 2010; Kastelein et al., 2014, 2015). This means that 
TTS predictions based on the total, SELcum will overestimate 
the amount of TTS from intermittent exposures, such as sonars and 
impulsive sources. Nachtigall et al. (2018) describe measurements of 
hearing sensitivity of multiple odontocete species (bottlenose dolphin, 
harbor porpoise, beluga, and false killer whale (Pseudorca crassidens)) 
when a relatively loud sound was preceded by a warning sound. These 
captive animals were shown to reduce hearing sensitivity when warned of 
an impending intense sound. Based on these experimental observations of 
captive animals, the authors suggest that wild animals may dampen their 
hearing during prolonged exposures or if conditioned to anticipate 
intense sounds. Additionally, the existing marine mammal TTS data come 
from a limited number of individuals within these species.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, but such relationships are assumed to be similar to 
those in humans and other terrestrial mammals. PTS typically occurs at 
exposure levels at least several dBs above that inducing mild TTS 
(e.g., a 40-dB TS approximates PTS onset (Kryter et al., 1966; Miller, 
1974), while a 6-dB TS approximates TTS onset (Southall et al., 2007, 
2019). Based on data from terrestrial mammals, a precautionary 
assumption is that the PTS thresholds for impulsive sounds (such as 
impact pile driving pulses as received close to the source) are at 
least 6 dB higher than the TTS threshold on a peak-pressure basis and 
PTS cumulative sound exposure level thresholds are 15 to 20 dB higher 
than TTS cumulative sound exposure level thresholds (Southall et al., 
2007, 2019). Given the higher level of sound or longer exposure 
duration necessary to cause PTS as compared with TTS, it is 
considerably less likely that PTS could occur.
    Behavioral Harassment--Exposure to noise from pile driving and 
removal and tension anchoring also has the potential to behaviorally 
disturb marine mammals. Available studies show wide variation in 
response to underwater sound; therefore, it is difficult to predict 
specifically how any given sound in a particular instance might affect 
marine mammals perceiving the signal. If a marine mammal does react 
briefly to an underwater sound by changing its behavior or moving a 
small distance, the impacts of the change are unlikely to be 
significant to the individual, let alone the stock or population. 
However, if a sound source displaces marine mammals from an important 
feeding or breeding area for a prolonged period, impacts on individuals 
and populations could be significant (e.g., Lusseau and Bejder, 2007; 
Weilgart, 2007; National Research Council (NRC), 2005).
    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); or avoidance of areas where sound sources are located. 
Pinnipeds may increase their haulout 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. Please see appendices B-C of Southall et al. 
(2007) and Gomez et al. (2016) for a review of studies involving marine 
mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2004). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure.
    As noted above, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; Wartzok et al., 2004; National

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Research Council (NRC), 2005). Controlled experiments with captive 
marine mammals have showed pronounced behavioral reactions, including 
avoidance of loud sound sources (Ridgway et al., 1997; Finneran et al., 
2003). Observed responses of wild marine mammals to loud pulsed sound 
sources (e.g., seismic airguns) have been varied but often consist of 
avoidance behavior or other behavioral changes (Richardson et al., 
1995; Morton and Symonds, 2002; Nowacek et al., 2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal (e.g., Erbe et al., 2019). If a marine mammal does react 
briefly to an underwater sound by changing its behavior or moving a 
small distance, the impacts of the change are unlikely to be 
significant to the individual, let alone the stock or population. 
However, if a sound source displaces marine mammals from an important 
feeding or breeding area for a prolonged period, impacts on individuals 
and populations could be significant (e.g., Lusseau and Bejder, 2007; 
Weilgart, 2007; NRC, 2005). However, there are broad categories of 
potential response, which we describe in greater detail here, that 
include alteration of dive behavior, alteration of foraging behavior, 
effects to breathing, interference with or alteration of vocalization, 
avoidance, and flight.
    Changes in dive behavior can vary widely and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al., 2004; Goldbogen et al., 2013a, 2013b, Blair et al., 2016). 
Variations in dive behavior may reflect interruptions in biologically 
significant activities (e.g., foraging) or they may be of little 
biological significance. The impact of an alteration to dive behavior 
resulting from an acoustic exposure depends on what the animal is doing 
at the time of the exposure and the type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. In response to playbacks of vibratory pile driving sounds, 
captive bottlenose dolphins showed changes in target detection and 
number of clicks used for a trained echolocation task (Branstetter et 
al. 2018). Similarly, harbor porpoises trained to collect fish during 
playback of impact pile driving sounds also showed potential changes in 
behavior and task success, though individual differences were prevalent 
(Kastelein et al. 2019d).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.
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996; Bowers et al., 2018). The result of a flight response 
could range from brief, temporary exertion and displacement from the 
area where the signal provokes flight to, in extreme cases, marine 
mammal strandings (England et al., 2001). However, it should be noted 
that response to a perceived predator does not necessarily invoke 
flight (Ford and Reeves, 2008), and whether individuals are solitary or 
in groups may influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fishes and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a 5-day period did not cause any sleep 
deprivation or stress effects.
    Stress Responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et

[[Page 1092]]

al., 2004; Lankford et al., 2005). Stress responses due to exposure to 
anthropogenic sounds or other stressors and their effects on marine 
mammals have also been reviewed (Fair and Becker, 2000; Romano et al., 
2002a) and, more rarely, studied in wild populations (e.g., Romano et 
al., 2002b). For example, Rolland et al. (2012) found that noise 
reduction from reduced ship traffic in the Bay of Fundy was associated 
with decreased stress in North Atlantic right whales. These and other 
studies lead to a reasonable expectation that some marine mammals will 
experience physiological stress responses upon exposure to acoustic 
stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003), however 
distress is an unlikely result of this project based on observations of 
marine mammals during previous, similar projects in the area.
    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.
    Airborne Acoustic Effects--Although pinnipeds are known to haul out 
regularly at two harbor seal haulout sites within Port Fredrick, NMFS 
expects that incidents of take resulting solely from airborne sound are 
unlikely due to their proximity. One of the haulouts (CE79A) is located 
approximately 10 km (6.25 mi) from the project site and is outside of 
the ensonfied zone for this action. The other (CF39A) is located 
approximately 3 km (2 mi) from the project site and will be ensonified 
during some vibratory and impact pile driving activities. Neither of 
these haulouts are listed as a ``key haulout,'' or a haulout with 50 or 
more individuals present at the time of survey (AFSC 2024).
    Cetaceans are not expected to be exposed to airborne sounds that 
would result in harassment as defined under the MMPA. Airborne noise 
would primarily be an issue for pinnipeds that are swimming or hauled 
out near the project site within the range of noise levels elevated 
above the acoustic criteria. We recognize that pinnipeds in the water 
could be exposed to airborne sound that may result in behavioral 
harassment when looking with their heads above water. Most likely, 
airborne sound would cause behavioral responses similar to those 
discussed above in relation to underwater sound. For instance, 
anthropogenic sound could cause hauled-out pinnipeds to exhibit changes 
in their normal behavior, such as reduction in vocalizations, or cause 
them to temporarily abandon the area and move further from the source. 
However, these animals would likely previously have been ``taken'' 
because of exposure to underwater sound above the behavioral harassment 
thresholds, which are generally larger than those associated with 
airborne sound. Thus, the behavioral harassment of these animals is 
already accounted for in these estimates of potential take. Therefore, 
we do not believe that authorization of incidental take resulting from 
airborne sound for pinnipeds is warranted, and airborne sound is not 
discussed further here.

Marine Mammal Habitat Effects

    Hoonah's construction activities could have localized, temporary 
impacts on marine mammal habitat by increasing in-water SPLs and 
slightly decreasing water quality. No net habitat loss is expected, 
since its proposed location is an existing barge ramp that already 
experiences frequent vessel traffic and is adjacent to an active road, 
ferry terminal, dock, boat haulout pier, and boat yard. Construction 
activities are localized and would likely have temporary impacts on 
marine mammal habitat through increases in underwater sounds. 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 activities, elevated 
levels of underwater noise would ensonify the project area where both 
fishes and marine mammals may occur and could affect foraging success. 
Additionally, marine mammals may avoid the area during construction; 
however, displacement due to noise is expected to be temporary and is 
not expected to result in long-term effects to the individuals or 
populations.
    Temporary and localized reduction in water quality would occur 
because of in-water construction activities as well. Most of this 
effect would occur during the installation and removal of piles when 
bottom sediments are disturbed. The installation of piles would disturb 
bottom sediments and may cause a temporary increase in suspended 
sediment in the project area. In general, turbidity associated with 
pile installation is localized to about 25-ft (7.6-m) radius around the 
pile (Everitt et al., 1980). Pinnipeds are not expected to be close 
enough to the pile driving areas to experience effects of turbidity, 
and could avoid localized areas of turbidity. Therefore, we expect the 
impact from increased turbidity levels to be discountable to marine 
mammals and do not discuss it further.

In-Water Construction Effects on Potential Foraging Habitat

    The proposed activities would not result in permanent impacts to 
habitats used directly by marine mammals outside of the actual 
footprint of the constructed dock. The total seafloor area affected by 
pile installation and removal is a very small area compared to the vast 
foraging area available to marine mammals in Port Fredrick and the 
surrounding waters. Pile extraction and installation and tension 
anchoring may have impacts on benthic invertebrate species primarily 
associated with disturbance of sediments that may cover or displace 
some invertebrates. The impacts would be temporary and highly 
localized, and no habitat would be permanently displaced by 
construction. Therefore, it is expected that impacts on foraging 
opportunities for marine mammals due to construction of the dock would 
be minimal.
    It is possible that avoidance by potential prey (i.e., fish) in the 
immediate area may occur due to temporary loss of this foraging 
habitat. The duration of fish avoidance of this area after pile driving 
stops is unknown,

[[Page 1093]]

but we anticipate a rapid return to normal recruitment, distribution 
and behavior. Any behavioral avoidance by fish of the disturbed area 
would still leave large areas of fish and marine mammal foraging 
habitat in the nearby vicinity in the in the project area and 
surrounding waters.

Effects on Potential Prey

    Construction activities would produce continuous (i.e., vibratory 
pile driving and tension anchoring) and intermittent (i.e., impact 
driving and tension anchoring) sounds. Sound may affect marine mammals 
through impacts on the abundance, behavior, or distribution of prey 
species (e.g., fish). Marine mammal prey varies by species, season, and 
location. Here, we describe studies regarding the effects of noise on 
known marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009). 
Depending on their hearing anatomy and peripheral sensory structures, 
which vary among species, fishes hear sounds using pressure and 
particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    Fish react to sounds which are especially strong and/or 
intermittent low-frequency sounds, and behavioral responses, such as 
flight or avoidance are the most likely effects. Short duration, sharp 
sounds can cause overt or subtle changes in fish behavior and local 
distribution. The reaction of fish to noise depends on the 
physiological state of the fish, past exposures, motivation (e.g., 
feeding, spawning, migration), and other environmental factors. 
Hastings and Popper (2005) identified several studies that suggest fish 
may relocate to avoid certain areas of sound energy. Additional studies 
have documented effects of pile driving on fish, although several are 
based on studies in support of large, multiyear bridge construction 
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 
2009). Several studies have demonstrated that impulse sounds might 
affect the distribution and behavior of some fishes, potentially 
impacting foraging opportunities or increasing energetic costs (e.g., 
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al., 
1992; Santulli et al., 1999; Paxton et al., 2017). However, some 
studies have shown no or slight reaction to impulse sounds (e.g., Pena 
et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott 
et al., 2012).
    SPLs of sufficient strength have been known to cause injury to 
fishes and fish mortality (summarized in Popper et al., 2014). However, 
in most fish species, hair cells in the ear continuously regenerate and 
loss of auditory function likely is restored when damaged cells are 
replaced with new cells. Halvorsen et al. (2012a) showed that a TTS of 
4 to 6 dB was recoverable within 24 hours for one species. Impacts 
would be most severe when the individual fish is close to the source 
and when the duration of exposure is long. Injury caused by barotrauma 
can range from slight to severe and can cause death, and is most likely 
for fish with swim bladders. Barotrauma injuries have been documented 
during controlled exposure to impact pile driving (Halvorsen et al., 
2012b; Casper et al., 2013, 2017).
    Fish populations in the proposed project area that serve as marine 
mammal prey could be temporarily affected by noise from pile 
installation and removal. The frequency range in which fishes generally 
perceive underwater sounds is 50 to 2,000 Hz, with peak sensitivities 
below 800 Hz (Popper and Hastings, 2009). Fish behavior or distribution 
may change, especially with strong and/or intermittent sounds that 
could harm fishes. High underwater SPLs have been documented to alter 
behavior, cause hearing loss, and injure or kill individual fish by 
causing serious internal injury (Hastings and Popper, 2005).
    The greatest potential impact to fishes during construction would 
occur during impact pile driving and tension anchoring. The duration of 
impact pile driving would be limited to the final stage of installation 
(``proofing'') after the pile has been driven as close as practicable 
to the design depth with a vibratory driver. Only a total of 10 tension 
anchors will be set over a total of 5 days of construction. In-water 
construction activities would only occur during daylight hours, 
allowing fish to forage and transit the project area in the evening. 
Vibratory pile driving could elicit behavioral reactions from fishes 
such as temporary avoidance of the area but is unlikely to cause 
injuries to fishes or have persistent effects on local fish 
populations. Construction also would have minimal permanent and 
temporary impacts on benthic invertebrate species, a marine mammal prey 
source.
    The area impacted by the project is relatively small compared to 
the available habitat in the remainder of Port Fredrick and the 
surrounding areas, and there are no areas of particular importance that 
would be impacted by this project. Any behavioral avoidance by fish of 
the disturbed area would still leave significantly large areas of fish 
and marine mammal foraging habitat in the nearby vicinity. As described 
in the preceding, the potential for Hoonah's construction to affect the 
availability of prey to marine mammals or to meaningfully impact the 
quality of physical or acoustic habitat is considered to be 
insignificant.

Estimated Take of Marine Mammals

    This section provides an estimate of the number of incidental takes 
proposed for authorization through the IHA, which will inform NMFS' 
consideration of ``small numbers,'' the negligible impact 
determinations, and impacts on subsistence uses.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment as use of 
the acoustic sources (i.e., pile driving and tension anchoring) 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 very high frequency species and 
phocids because predicted auditory injury zones are larger than for 
high-frequency species and otariids. 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

[[Page 1094]]

available science indicates marine mammals will likely be behaviorally 
harassed or incur some degree of permanent hearing impairment; (2) the 
area or volume of water that will be ensonified above these levels in a 
day; (3) the density or occurrence of marine mammals within these 
ensonified areas; and, (4) the number of days of activities. We note 
that while these factors can contribute to a basic calculation to 
provide an initial prediction of potential takes, additional 
information that can qualitatively inform take estimates is also 
sometimes available (e.g., previous monitoring results or average group 
size). Below, we describe the factors considered here in more detail 
and present the proposed take estimates.

Acoustic Criteria

    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 auditory injury of some degree (equated 
to Level A harassment). We note that the criteria for auditory injury, 
as well as the names of two hearing groups, have been recently updated 
(NMFS 2024a) as reflected below in the Level A Harassment section.
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012). 
Based on what the available science indicates and the practical need to 
use a threshold based on a metric that is both predictable and 
measurable for most activities, NMFS typically uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS generally predicts that marine mammals are 
likely to be behaviorally harassed in a manner considered to be Level B 
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced 
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile 
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g., 
scientific sonar) sources. Generally speaking, Level B harassment take 
estimates based on these behavioral harassment thresholds are expected 
to include any likely takes by TTS as, in most cases, the likelihood of 
TTS occurs at distances from the source less than those at which 
behavioral harassment is likely. TTS of a sufficient degree can 
manifest as behavioral harassment, as reduced hearing sensitivity and 
the potential reduced opportunities to detect important signals 
(conspecific communication, predators, prey) may result in changes in 
behavior patterns that would not otherwise occur.
    Hoonah's proposed activity includes the use of continuous 
(vibratory pile driving, tension anchoring) and impulsive (impact pile 
driving, tension anchoring) sources, and therefore the RMS SPL 
thresholds of 120 and 160 dB re 1 [mu]Pa are applicable. Tension 
anchoring has both continuous and intermittent components as discussed 
in the Description of Sound Sources section above. When evaluating 
Level B harassment, NMFS recommends treating tension anchoring as a 
continuous source and applying the RMS SPL thresholds of 120 dB re 1 
[mu]Pa.
    Level A harassment--NMFS' Updated Technical Guidance for Assessing 
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 
3.0) (Updated Technical Guidance, 2024) identifies dual criteria to 
assess auditory injury (Level A harassment) to five different 
underwater marine mammal groups (based on hearing sensitivity) as a 
result of exposure to noise from two different types of sources 
(impulsive or non-impulsive). Hoonah's proposed activity includes the 
use of impulsive (impact pile driving, tension anchoring) and non-
impulsive (vibratory pile driving, tension anchoring) sources. Tension 
anchoring includes both impulsive and non-impulsive characteristics. 
When evaluating Level A harassment, NMFS recommends treating tension 
anchoring as an impulsive source.
    The 2024 Updated Technical Guidance criteria include both updated 
thresholds and updated weighting functions for each hearing group. The 
thresholds are provided in the table below. The references, analysis, 
and methodology used in the development of the criteria are described 
in NMFS' 2024 Updated Technical Guidance, which may be accessed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools.

                          Table 4--Thresholds Identifying the Onset of Auditory Injury
----------------------------------------------------------------------------------------------------------------
                                              Auditory injury onset acoustic thresholds * (received level)
             Hearing group             -------------------------------------------------------------------------
                                                Impulsive                          Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans..........  Cell 1: Lp,0-pk,flat: 222  Cell 2: LE,LF,24h: 197 dB.
                                         dB; LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans.........  Cell 3: Lp,0-pk,flat: 230  Cell 4: LE,HF,24h: 201 dB.
                                         dB; LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans...  Cell 5: Lpk,0-pk,flat:     Cell 6: LE,p,VHF,24h: 181 dB.
                                         202 dB; LE,p,VHF,24h:
                                         159 dB.
Phocid Pinnipeds (PW) (Underwater)....  Cell 7: Lp,0-pk,flat: 223  Cell 8: LE,p,PW,24h: 195 dB.
                                         dB; LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)...  Cell 9: Lp,0-pk,flat: 230  Cell 10: LE,p,OW,24h: 199 dB.
                                         dB; LE,p,OW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric criteria for impulsive sounds: Use whichever criteria results in the larger isopleth for
  calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure
  level criteria associated with impulsive sounds, the PK SPL criteria are recommended for consideration for non-
  impulsive sources.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa (underwater) and 20 [micro]Pa (in
  air), and weighted cumulative sound exposure level (LE,p) has a reference value of 1 [micro]Pa2s (underwater)
  and 20 [micro]Pa2s (in air). In this table, criteria are abbreviated to be more reflective of International
  Organization for Standardization standards (ISO 2017; ISO 2020). The subscript ``flat'' is being included to
  indicate peak sound pressure are flat weighted or unweighted within the generalized hearing range of marine
  mammals underwater (i.e., 7 Hz to 165 kHz) or in air (i.e., 42 Hz to 52 kHz). The subscript associated with
  cumulative sound exposure level criteria indicates the designated marine mammal auditory weighting function
  (LF, HF, and VHF cetaceans, and PW, OW, PA, and OA pinnipeds) and that the recommended accumulation period is
  24 hours. The weighted cumulative sound exposure level criteria 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 criteria will be exceeded.

[[Page 1095]]

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. 
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. Marine mammals are expected to 
be affected via sound generated by the primary components of the 
project (i.e., vibratory pile driving and removal, impact pile driving, 
and tension anchoring).
    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 project, 
the applicant and 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, steel fender piles, steel sheet piles, steel H-piles, steel wye 
piles, steel X piles, and steel batter piles and tension anchoring 
drilling. Source levels for each pile size and driving method are 
presented in table 5.
    NMFS recommends treating DTH systems as both impulsive and 
continuous, non-impulsive sound source types simultaneously. Thus, 
impulsive thresholds are used to evaluate Level A harassment, and 
continuous thresholds are used to evaluate Level B harassment. NMFS 
(2022) outlines its recommended source levels for DTH systems. NMFS has 
applied that guidance in this analysis (see Table 5 for NMFS' proposed 
source levels).

                  Table 5--Proxy Sound Source Levels at 10 m for Pile Sizes and Driving Methods
----------------------------------------------------------------------------------------------------------------
                                                 SEL (re 1
            Pile type              RMS SPL (re   [mu]Pa\2\-   Peak SPL (re 1                Source
                                    1 [mu]Pa)       sec)         [mu]Pa)
----------------------------------------------------------------------------------------------------------------
                                             Vibratory Pile Driving
----------------------------------------------------------------------------------------------------------------
Temporary 24-in steel pipe piles.          162           NA               NA  PR1 2023 calculations (cited in
                                                                               NMFS 2023).
20-in steel fender piles.........  ...........  ...........  ...............  ..................................
Steel sheet piles................          160  ...........  ...............  Caltrans 2015 (cited in NMFS
                                                                               2023).
16-in steel fender piles.........          155  ...........  ...............  PR1 2023 calculations (cited in
                                                                               NMFS 2023).
H-piles..........................          150  ...........  ...............  PR1 2023 calculations (cited in
                                                                               NMFS 2023).
Wye piles........................  ...........  ...........  ...............  NMFS 2024.
X piles..........................
36-in steel pile.................          166  ...........  ...............  PR1 2023 calculations (cited in
                                                                               NMFS 2023).
----------------------------------------------------------------------------------------------------------------
                                               Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
20-in steel fender piles.........          190          177              203  Caltrans 2015 (cited in NMFS
                                                                               2023).
Steel sheet piles................          190          180              205  Caltrans 2015 (cited in NMFS
                                                                               2023).
16-in steel fender piles.........          185          175              200  Caltrans 2020 (cited in NMFS
                                                                               2023).
H-piles..........................          183          170              210  Caltrans 2015 (cited in NMFS
                                                                               2023).
Wye piles........................
X piles..........................
36-in steel pile.................          193          183              210  Caltrans 2015 & 2020 (cited in
                                                                               NMFS 2023).
----------------------------------------------------------------------------------------------------------------
                                                Tension Anchoring
----------------------------------------------------------------------------------------------------------------
6-8 in anchor hole...............          156          144              170  NMFS 2022.
----------------------------------------------------------------------------------------------------------------

    All Level B harassment isopleths are reported in Table 6 below. The 
maximum (underwater) area ensonified above the thresholds for 
behavioral harassment is 43 km\2\ (16.6 mi\2\). However, that zone 
would be truncated

[[Page 1096]]

by land masses that would obstruct underwater sound transmission and 
would be limited to Port Fredrick (see figure 4 in Trident's 
application).
    The ensonified area associated with Level A harassment is more 
technically challenging to predict due to the need to account for a 
duration component. Therefore, NMFS developed an optional User 
Spreadsheet tool to accompany the 2024 Updated Technical Guidance that 
can be used to relatively simply predict an isopleth distance for use 
in conjunction with marine mammal density or occurrence to help predict 
potential takes. We note that because of some of the assumptions 
included in the methods underlying this optional tool, we anticipate 
that the resulting isopleth estimates are typically going to be 
overestimates of some degree, which may result in an overestimate of 
potential take by Level A harassment. However, this optional tool 
offers the best way to estimate isopleth distances when more 
sophisticated modeling methods are not available or practical. For 
stationary sources such as pile driving, 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 auditory injury. Inputs used in the optional User Spreadsheet 
tool, and the resulting estimated isopleths, are reported below.

                                                          Table 6--NMFS User Spreadsheet Inputs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                Activity
                                                                      Weighting factor    Transmission loss  Number of piles  duration per    Number of
           Pile size and type               Spreadsheet tab used      adjustment (kHz)       coefficient         per day          pile       strikes per
                                                                                                                                (minutes)       pile
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Vibratory Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary 24-in steel pipe piles.......  A.1 Vibratory pile driving                 2.5                  15                6            15            NA
20-in steel fender piles...............  ..........................                 2.5                  15                3            30            NA
Steel sheet piles......................  ..........................                 2.5                  15               30            15            NA
16-in steel fender piles...............  ..........................                 2.5                  15                2            30            NA
H-piles................................  ..........................                 2.5                  15                2            30            NA
Wye piles..............................  ..........................                 2.5                  15                3            30            NA
X piles................................  ..........................                 2.5                  15                1            30            NA
36-in steel pipe pile..................  ..........................                 2.5                  15                2            60            NA
36-in steel batter pile................  ..........................                 2.5                  15                2            60            NA
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Impact Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
20-in steel fender piles...............  E.1. Impact pile driving..                   2                  15                3            30           600
Steel sheet piles......................  ..........................                   2                  15               15            30           200
16-in steel fender piles...............  ..........................                   2                  15                2            30           600
H-piles................................  ..........................                   2                  15                2            30           600
Wye piles..............................  ..........................                   2                  15                2            30           200
X piles................................  ..........................                   2                  15                1            30           200
36-in steel pipe pile..................  ..........................                   2                  15                2            60         1,200
36-in steel batter pile................  ..........................                   2                  15                4            60         1,200
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Tension Anchoring
--------------------------------------------------------------------------------------------------------------------------------------------------------
6-8 in anchor hole.....................  E.2 DTH pile driving......                   2                  15                2            60       108,000
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                              Table 7--Calculated Level A and Level B Harassment Isopleths
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                    Level A harassment zone (m)                               Level B
                        Activity                         --------------------------------------------------------------------------------   harassment
                                                           LF-cetaceans    HF-cetaceans    VHF-cetaceans      Phocids        Otariids        zone (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Vibratory Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary 24-in steel pipe piles........................            16.4             6.3            13.4            21.1             7.1         7,356.4
20-in steel fender piles................................  ..............  ..............  ..............  ..............  ..............  ..............
Steel sheet piles.......................................            30.3            11.6            24.8            39.0            13.1         4,641.6
16-in steel fender piles................................             3.7             1.4             3.0             4.4             1.6         2,154.4
H-piles.................................................             1.7             0.7             1.4             2.2             0.7         1,000.0
Wye piles...............................................  ..............  ..............  ..............  ..............  ..............  ..............
X piles.................................................             1.1             0.4             0.9             1.4             0.5
36-in steel pipe pile...................................            31.5            12.1            25.8            40.6            13.7        11,659.1
36-in steel batter pile.................................  ..............  ..............  ..............  ..............  ..............  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Impact Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
20-in steel fender piles................................           586.1            74.8           907.1           520.7           194.1         1,000.0
Steel sheet piles.......................................         1,305.9           166.6         2,020.9         1,160.1           432.4  ..............
16-in steel fender piles................................           329.1            42.0           509.2           292.3           109.0           462.2
H-piles.................................................           152.7            19.5           236.4           135.7            50.6           341.5
Wye piles...............................................            73.4             9.4           113.6            65.2            24.3  ..............
X piles.................................................            46.3             5.9            71.6            41.1            15.3  ..............
36-in steel pipe pile...................................         1,783.6           227.6         2,760.1         1,584.5           590.6         1,584.9
36-in steel batter pile.................................         2,831.3           361.2         4,381.4         2,515.2           937.6  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 1097]]

 
                                                                    Tension Anchoring
--------------------------------------------------------------------------------------------------------------------------------------------------------
6-8 in anchor hole......................................            90.0            11.5           139.2            79.9            29.8         2,512.0
--------------------------------------------------------------------------------------------------------------------------------------------------------

Marine Mammal Occurrence and Take Estimation

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information which 
will inform the take calculations.
    Consultation with the Hoonah Harbormaster, applications and reports 
from other nearby in water construction projects, and available 
scientific literature are used to estimate the occurrence of marine 
mammals in the action area. Daily occurrence probability of each marine 
mammal species in the action area is based on historic data of 
occurrence, seasonality, and group size in Port Frederick and Icy 
Strait, and other nearby waters.
    Here we describe how the information provided above is synthesized 
to produce a quantitative estimate of the take that is reasonably 
likely to occur and proposed for authorization. Tables for each species 
are presented to show the calculation of take during the project. NMFS 
used the following equations to estimate take.

Incidental take estimate (daily) = group size * groups per day * days 
of pile driving activity (107 days)
Incidental take estimate (monthly) = group size * groups per month 
(considered 30 days) * months of pile driving activity (107 days/30 
days per month)
Minke Whale
    There are a few sightings of minke whales every year, so they could 
occur every month during the project. They typically occur in groups of 
two to three individuals (NMFS 2023d). Up to one group of three minke 
whales are expected to occur in the project area per month. Therefore, 
using the monthly equation above, NMFS proposes to authorize 11 takes 
by Level B harassment of minke whales.
    The largest Level A harassment zone for minke whales extends 2,831 
m from the sound source (table 7). All construction work would be shut 
down prior to a minke whale entering the Level A harassment zone 
specific to the in-water activity underway at the time. In 
consideration of the infrequent occurrence of minke whales in the 
project area and proposed shutdown requirements, no take by Level A 
harassment of minke whales is anticipated or proposed for 
authorization.
Humpback Whale
    There are multiple sightings of humpback whales every month, and 
they could occur every day during the project. They typically occur in 
groups of one to two individuals (Dahlheim et al., 2009). Up to one 
group of two humpback whales are expected to occur in the project area 
per day. Therefore, using the daily equation above, NMFS proposes to 
authorize 214 takes by Level B harassment of humpback whales. In the 
project area, it is estimated that the majority of whales (98 percent) 
would be from the Hawaii DPS and 2 percent will be from the Mexico DPS 
(Wade 2021; Muto et al. 2022). Therefore, of the 214 takes by Level B 
harassment, NMFS anticipates that 210 takes would be of individuals 
from the Hawaii DPS and 4 takes of individuals from the Mexico DPS.
    The largest Level A harassment zone for humpback whales extends 
2,831 m from the sound source (table 7). All construction work would be 
shut down prior to a humpback whale entering the Level A harassment 
zone specific to the in-water activity underway at the time. In 
consideration that humpback whales are most often seen in Icy Strait 
and the mouth of Port Fredrick and proposed shutdown requirements, no 
take by Level A harassment is anticipated or proposed for authorization 
for humpback whales.
Killer Whale
    There are multiple sightings of killer whales every year, and they 
could occur every month during the project. They typically occur in 
groups of one to five individuals (NMFS 2023e). Up to four groups of 
five killer whales (i.e., 20 killer whales total) are expected to occur 
in the project area per month. Therefore, using the monthly equation 
given above, NMFS proposes to authorize 72 takes by Level B harassment 
of killer whales.
    The largest Level A harassment zone for killer whales extends 361 m 
from the sound source (table 7). All construction work would be shut 
down prior to a killer whale entering the Level A harassment zone 
specific to the in-water activity underway at the time. In 
consideration of the small size of the Level A harassment zone and 
proposed shutdown requirements, no take by Level A harassment of killer 
whales is anticipated or proposed for authorization.
Pacific White-Sided Dolphin
    There are a few sightings of Pacific white-sided dolphins every 
year, but there are no sightings from recent years. However, to avoid 
underestimating potential impacts from the project, in estimating take, 
NMFS assumes they could occur every other month (i.e., one group every 
60 days) during the project. They occur in groups of 2 to 153 
individuals, but are most commonly seen in groups of 23-26 individuals 
(Dahlheim et al., 2009). NMFS anticipates that up to one group of 26 
Pacific white-sided dolphins could occur in the project area every 
other month. Using the monthly equation above suggests that there could 
be 47 takes by Level B harassment of Pacific white-sided dolphins. 
However, since these dolphins can occur in large groups, NMFS proposes 
to authorize 153 takes by Level B harassment in case a larger pod is 
observed.
    The largest Level A harassment zone for Pacific white-sided 
dolphins extends 361 m from the sound source (table 7). All 
construction work would be shut down prior to a Pacific white-sided 
dolphin entering the Level A harassment zone specific to the in-water 
activity underway at the time. In consideration of the small size of 
the Level A harassment zone, proposed shutdown requirements, and 
infrequent occurrence of Pacific white-sided dolphins, no take by Level 
A harassment of Pacific white-sided dolphins is anticipated or proposed 
for authorization.
Dall's Porpoise
    There are multiple sightings of Dall's porpoises every year, and 
they could occur every month during the project. They typically occur 
in groups of two to five individuals (Dahlheim et al., 2009). NMFS 
anticipates that up to four groups

[[Page 1098]]

of five Dall's porpoises (i.e., 20 Dall's porpoises total) could occur 
in the project area per month. Therefore, using the monthly equation 
given above, NMFS proposes to authorize 72 takes by Level B harassment 
of Dall's porpoises.
    The largest Level A harassment zone for Dall's porpoises extends 
4,381 m from the sound source (table 7) during impact pile driving. 
Hoonah would be required to implement shutdowns during all pile driving 
activities. However, during impact pile driving of the 20-in fender 
piles, 16-in fender piles, sheet piles, and 36-in piles, the Level A 
harassment zones for Dall's porpoise extend beyond the shutdown zones, 
and NMFS anticipates that Level A harassment could occur. Hoonah 
estimates, and NMFS concurs, that up to four groups of two Dall's 
porpoises could occur in the Level A harassment zone for a duration 
long enough to incur auditory injury during each month of impact pile 
driving (42 days of pile driving). Using the monthly equation above, 
NMFS proposes to authorize 12 takes by Level A harassment of Dall's 
porpoises.
Harbor Porpoise
    There are multiple sightings of harbor porpoises every month, and 
they could occur every day during the project. They typically occur in 
groups of one to three individuals (Dahlheim et al., 2009). Up to one 
group of three harbor porpoises are expected to occur in the project 
area per day. Therefore, using the daily equation given above, NMFS 
proposes to authorize 321 takes by Level B harassment of harbor 
porpoises.
    The largest Level A harassment zone for harbor porpoises extends 
4,381 m from the sound source (table 7) during impact pile driving. 
Hoonah would be required to implement shutdowns during all pile driving 
activities. However, during impact pile driving of the 20-in fender 
piles, 16-in fender piles, sheet piles, and 36-in piles, the Level A 
harassment zones for the harbor porpoise extend beyond the shutdown 
zone, and NMFS anticipates that Level A harassment could occur. Hoonah 
expects, and NMFS concurs, that up to one group of two harbor porpoises 
could be present in the Level A harassment zone for each day of impact 
pile driving (42 days of pile driving). Using the daily equation given 
above, NMFS proposes to authorize 84 takes by Level A harassment of 
harbor porpoises.
Harbor Seal
    There are a multiple sightings of harbor seals every month, and 
they could occur every day during the project. They typically occur in 
groups of one to four individuals (Jefferson et al., 2019). Up to one 
group of two harbor seals are expected to occur in the project area per 
day. Therefore, using the daily equation given above, NMFS proposes to 
authorize 214 takes by Level B harassment of harbor seals. Additionally 
there is a harbor seal haulout located three km (1.9 mi) from the 
project site where harbor seals congregate in larger numbers. Hoonah 
estimated, and NMFS concurs that up to 1 group of 20 harbor seals could 
be taken by Level B harassment every month that the Level B harassment 
zone is larger than 2,000 m (43 days of pile driving). Therefore, using 
the monthly equation given above, NMFS proposes to authorize an 
additional 29 takes by Level B harassment of harbor seals. 
Cumulatively, NMFS proposes to authorize 243 takes by Level B 
harassment of harbor seals.
    The largest Level A harassment zone for harbor seals extends 2,515 
m from the sound source (table 7) during impact pile driving. Hoonah 
would be required to implement shutdowns during all pile driving 
activities. However, during impact pile driving of the 20-in fender 
piles, 16-in fender piles, sheet piles, and 36-in piles, the Level A 
harassment zones for the harbor porpoise extend beyond the shutdown 
zone, and NMFS anticipates that Level A harassment could occur. Hoonah 
expects, and NMFS concurs, that up to one harbor seal could be present 
in the Level A harassment zone for each day of impact pile driving (42 
days of pile driving). Using the equation given above, the calculated 
estimated take by Level A harassment for harbor seals would be 42.
Steller Sea Lion
    There are a multiple sightings of Steller sea lions every month, 
and they could occur every day during the project. They typically occur 
in groups of one to four individuals (NMFS 2023f). Up to one group of 
four Steller sea lions is expected to occur in the project area per 
day. Therefore, using the daily equation given above, NMFS proposes to 
authorize 428 takes by Level B harassment of Steller sea lions. Both 
the Eastern DPS and Western DPS of Steller sea lions occur in the 
project area. NMFS estimates that the majority of Steller sea lions in 
the project area (99.6 percent) would be from the Eastern DPS and 1.4 
percent would be from the Western DPS (Hastings et al., 2020). 
Therefore, of the 428 total takes by Level B harassment, NMFS 
anticipates that 422 takes would be of individuals from the Eastern DPS 
and 6 takes of individuals from the Western DPS.
    The largest Level A harassment zone for Steller sea lions extends 
938 m from the sound source (table 7). All construction work would be 
shut down prior to a Steller sea lion entering the Level A harassment 
zone specific to the in-water activity underway at the time. In 
consideration of the proposed shutdown requirements, no take by Level A 
harassment is anticipated or proposed for Steller sea lions.

                                     Table 8--Estimated Take by Level A and Level B Harassment, by Species and Stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Stock                                                   Proposed take as
                Common name                               Stock               abundance      Level A       Level B     Total proposed    percentage of
                                                                                 \1\       harassment    harassment         take           stock \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Minke whale................................  Alaska........................          UND             0            11               11            \3\ UND
Humpback whale.............................  Hawaii DPS....................       11,278             0           214              214                1.9
                                             Mexico DPS....................        3,477  ............  ............  ...............                6.1
Killer whale...............................  Eastern North Pacific Alaska          1,920             0            72               72                3.8
                                              Resident.
                                             West Coast Transient..........          349  ............  ............  ...............               20.6
                                             Eastern North Pacific Northern          302  ............  ............  ...............               23.8
                                              Resident.
Pacific white-sided dolphin................  North Pacific.................       26,880             0           153              153                0.6
Dall's porpoise............................  Alaska........................          UND            12            72               83            \4\ UND
Harbor porpoise............................  Northern Southeast Alaska             1,619            84           321              403               24.9
                                              Inland Waters.
Harbor seal................................  Glacier Bay/Icy Strait........        7,455            42           243              298                4.0
Steller sea lion...........................  Western DPS...................       49,837             0           428              428                0.9
                                             Eastern DPS...................       36,308  ............  ............  ...............                1.2
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Stock size is Nbest according to NMFS 2023 Draft SARs, unless otherwise noted.

[[Page 1099]]

 
\2\ Percent of stock reflects the combined total of take by Level B and Level A harassment (if requested). If a species has multiple stocks, NMFS
  conservatively assumes that all takes occur to each stock.
\3\ The Alaska SAR does not have an estimated population size for the Alaska stock of minke whales due to only a portion of the stock's range being
  surveyed and such few whales seen during stock abundance surveys.
\4\ NMFS does not have an official abundance estimate for this stock, and the minimum population estimate is considered to be unknown (Young et al.,
  2023). See Small Numbers for additional discussion.

Proposed Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting the 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks, and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, NMFS 
considers two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned); and
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, and impact on 
operations.
    The mitigation measures described in the following paragraphs would 
apply to the Hoonah's in-water construction activities.

Shutdown Zones and Monitoring

    Hoonah must establish shutdown zones for all pile driving 
activities. The purpose of a shutdown zone is generally to define an 
area within which shutdown of the activity would occur upon sighting of 
a marine animal (or in anticipation of an animal entering the defined 
area). Shutdown zones vary based on the activity type and duration and 
marine mammal hearing group, as shown in table 9. A minimum shutdown 
zone of 10 m would be required for all in-water construction activities 
to avoid physical interaction with marine mammals. Marine mammal 
monitoring would be conducted during all pile driving activities to 
ensure that shutdowns occur, as required. Proposed shutdown zones for 
each activity type are shown in table 9.
    Prior to pile driving, shutdown zones would be established based on 
zones represented in table 9. Observers would survey the shutdown zones 
for at least 30 minutes before pile driving activities start. If marine 
mammals are observed within the shutdown zone, pile driving and tension 
anchoring will be delayed until the animal has moved out of the 
shutdown zone, either verified by an observer or by waiting until 15 
minutes has elapsed without a sighting of small cetaceans, delphinids, 
and pinnipeds; or 30 minutes has elapsed without a sighting of a large 
cetacean. If a marine mammal approaches or enters the shutdown zone 
during pile driving or tension anchoring, the activity would be halted. 
If a species for which authorization has not been granted, or a species 
which has been granted but the authorized takes are met, is observed 
approaching or within the Level B harassment zone during pile driving 
or tension anchoring, the activity would be halted. Pile driving may 
resume after the animal has moved out of and is moving away from the 
shutdown zone (or Level B harassment zone for which authorization has 
not been granted, or a species which has been granted but the 
authorized takes are met) or after at least 15 minutes has passed since 
the last observation of the animal.
    All marine mammals would be monitored in the Level B harassment 
zones and throughout the area as far as visual monitoring can take 
place. If a marine mammal enters the Level B harassment zone, in-water 
activities would continue and PSOs would document the animal's presence 
within the estimated harassment zone.

                                               Table 9--Shutdown and Level B Harassment Zones by Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                     Minimum shutdown zone (m)                                Level B
                        Activity                         --------------------------------------------------------------------------------   harassment
                                                           LF- cetaceans   HF- cetaceans  VHF- cetaceans      Phocids        Otariids        zone (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Vibratory Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary 24-in steel pipe piles........................              20              10              15              25              10           7,360
20-in steel fender piles................................  ..............  ..............  ..............  ..............  ..............  ..............
Steel sheet piles.......................................              35              15              25              40              15           4,645
16-in steel fender piles................................              10              10              10              10              10           2,155
H-piles.................................................              10              10              10              10              10           1,000
Wye piles...............................................  ..............  ..............  ..............  ..............  ..............  ..............
X piles.................................................  ..............  ..............  ..............  ..............  ..............  ..............
36-in steel pipe pile...................................              35              15              30              45              15          11,660
36-in steel batter pile.................................  ..............  ..............  ..............  ..............  ..............  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Impact Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
20-in steel fender piles................................             590              75             200             200             195           1,000
Steel sheet piles.......................................           1,310             170             200             200             435  ..............
16-in steel fender piles................................             330              42             200             200             110             465
H-piles.................................................             155              20             200             140              55             345
Wye piles...............................................              75              10             115              70              25  ..............
X piles.................................................              50              10              75              45              20  ..............

[[Page 1100]]

 
36-in steel pipe pile...................................           1,785             230             200             200             595          1,5890
36-in steel batter pile.................................           2,835             365             200             200             940  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Tension Anchoring
--------------------------------------------------------------------------------------------------------------------------------------------------------
6-8 in anchor hole......................................              90              15             140              80              30           2,515
--------------------------------------------------------------------------------------------------------------------------------------------------------

Protected Species Observers

    The placement of Protected Species Observers (PSO) during all pile 
driving activities (described in the Proposed Monitoring and Reporting 
section) would ensure that the entire shutdown zone is visible. Should 
environmental conditions deteriorate such that the entire shutdown zone 
would not be visible (e.g., fog, heavy rain), pile driving would be 
delayed until the PSO is confident marine mammals within the shutdown 
zone could be detected.
    PSOs would monitor the full shutdown zones and as much of the Level 
B harassment zones as possible. Monitoring enables observers to be 
aware of and communicate the presence of marine mammals in the project 
areas outside the shutdown zones and thus prepare for a potential 
cessation of activity should the animal enter the shutdown zone.

Pre- and Post-Activity Monitoring

    Monitoring must take place from 30 minutes prior to initiation of 
pile driving activities (i.e., pre-clearance monitoring) through 30 
minutes post-completion of pile driving. Prior to the start of daily 
in-water construction activity, or whenever a break in pile driving of 
30 minutes or longer occurs, PSOs would observe the shutdown and 
monitoring zones for a period of 30 minutes. The shutdown zone would be 
considered cleared when a marine mammal has not been observed within 
the zone for a 30-minute period. If a marine mammal is observed within 
the shutdown zones, pile driving activity would be delayed or halted. 
If work ceases for more than 30 minutes, the pre-activity monitoring of 
the shutdown zones would commence. A determination that the shutdown 
zone is clear must be made during a period of good visibility (i.e., 
the entire shutdown zone and surrounding waters must be visible to the 
naked eye).

Soft Start

    Soft-start procedures provide additional protection to marine 
mammals by providing warning and/or giving marine mammals a chance to 
leave the area prior to the impact hammer operating at full capacity. 
Hoonah must implement soft start techniques when impact pile driving. 
Soft start requires contractors to conduct an initial set of three 
strikes at reduced energy, followed by a 30-second waiting period, then 
two subsequent three-strike sets before initiating continuous driving. 
Soft start will 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.
    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least practicable impact on the 
affected species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present while 
conducting the activities. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
     Mitigation and monitoring effectiveness.

Visual Monitoring

    Marine mammal monitoring must be conducted in accordance with the 
Marine Mammal Monitoring and Mitigation Plan and section 5 of the IHA. 
Hoonah's draft Marine Mammal Monitoring and Mitigation Plan is Appendix 
D of the IHA application. Prior to the beginning of construction, 
Hoonah would submit a revised Marine Mammal Mitigation and Monitoring 
Plan containing additional details of monitoring locations and 
methodology for NMFS concurrence.
    Marine mammal monitoring during pile driving and removal must be 
conducted by NMFS-approved PSOs in a manner consistent with the 
following:
     PSOs must be independent of the activity contractor (for 
example, employed by a subcontractor) and have no other assigned tasks 
during monitoring periods;
     At least one PSO must have prior experience performing the 
duties of a PSO during construction activity

[[Page 1101]]

pursuant to a NMFS-issued incidental take authorization;
     Other PSOs may substitute education (degree in biological 
science or related field) or training for prior experience performing 
the duties of a PSO during construction activity pursuant to a NMFS-
issued incidental take authorization. PSOs may also substitute Alaska 
native traditional knowledge for experience;
     Where a team of three or more PSOs is required, a lead 
observer or monitoring coordinator must be designated. The lead 
observer must have prior experience performing the duties of a PSO 
during construction activity pursuant to a NMFS-issued incidental take 
authorization; and PSOs must be approved by NMFS prior to beginning any 
activity subject to this IHA.
    PSOs must have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and marine mammal behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    Between one and three PSOs will be on duty depending on the size of 
the Level B harassment zone. PSOs will establish monitoring locations 
as described in the Marine Mammal Mitigation and Monitoring Plan. 
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.
    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.

Data Collection

    PSOs would use approved data forms to record the following 
information:
     Dates and times (beginning and end) of all marine mammal 
monitoring; and
     PSO locations during marine mammal monitoring.
     Construction activities occurring during each daily 
observation period, including how many and what type of piles were 
driven or removed and by what method (i.e., vibratory, impact, or 
tension anchoring).
     Weather parameters and water conditions;
     The number of marine mammals observed, by species, 
relative to the pile location and if pile driving or removal was 
occurring at time of sighting;
     Distance and bearings of each marine mammal observed to 
the pile being driven or removed;
     Description of marine mammal behavior patterns, including 
direction of travel;
     Age and sex class, if possible, of all marine mammals 
observed; and
     Detailed information about implementation of any 
mitigation triggered (such as shutdowns and delays), a description of 
specific actions that ensued, and resulting behavior of the animal if 
any.

Reporting

    A draft marine mammal monitoring report would be submitted to NMFS 
within 90 days after the completion of monitoring or 60 calendar days 
prior to the requested issuance of any subsequent IHA for construction 
activity at the same location, whichever comes first. 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, vibratory, tension 
anchoring). The total duration of driving time must be recorded for 
each pile during vibratory driving and, number or strikes for each pile 
during impact driving, and the duration of operation of drilling and 
components for tension anchoring;
     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: (1) name of PSO who sighted the animal(s) and PSO location 
and activity at time of sighting; (2) time of sighting; (3) 
identification of the animal(s) (e.g., genus/species, lowest possible 
taxonomic level, or unidentified), PSO confidence in identification, 
and the composition of the group if there is a mix of species; (4) 
distance and bearing of each marine mammal observed relative to the 
pile being driven for each sighting (if pile driving was occurring at 
time of sighting); (5) estimated number of animals (min/max/best 
estimate); (6) estimated number of animals by cohort (adults, 
juveniles, neonates, group composition, etc.); (7) animal's closest 
point of approach and estimated time spent within the harassment zone; 
and (8) description of any marine mammal behavioral observations (e.g., 
observed behaviors such as feeding or traveling), including an 
assessment of behavioral responses thought to have resulted from the 
activity (e.g., no response or changes in behavioral state such as 
ceasing feeding, changing direction, flushing, or breaching);
     Number of marine mammals detected within the harassment 
zones, by species; and
     Detailed information about 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 event that personnel involved in the construction activities 
discover an injured or dead marine mammal, Hoonah shall report the 
incident to the Office of Protected Resources (OPR), NMFS and to the 
Alaska regional

[[Page 1102]]

stranding network as soon as feasible. If the death or injury was 
clearly caused by the specified activity, Hoonah must immediately cease 
the specified activities until NMFS is able to review the circumstances 
of the incident and determine what, if any, additional measures are 
appropriate to ensure compliance with the terms of the IHA. The IHA-
holder must not resume their activities until notified by NMFS. The 
report must include the following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and,
     General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), as well as 
effects on habitat, and the likely effectiveness of the mitigation. We 
also assess the number, intensity, and context of estimated takes by 
evaluating this information relative to population status. Consistent 
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338, 
September 29, 1989), the impacts from other past and ongoing 
anthropogenic activities are incorporated into this analysis via their 
impacts on the baseline (e.g., as reflected in the regulatory status of 
the species, population size and growth rate where known, ongoing 
sources of human-caused mortality, or ambient noise levels).
    To avoid repetition, the majority of our analysis applies to all 
the species listed in table 2, given that many of the anticipated 
effects of this project on different marine mammal stocks are expected 
to be relatively similar in nature. Where there are meaningful 
differences between species or stocks, or groups of species, in 
anticipated individual responses to activities, impact of expected take 
on the population due to differences in population status, or impacts 
on habitat, they are described independently in the analysis below.
    Pile driving and tension anchoring activities have the potential to 
disturb or displace marine mammals. Specifically, the project 
activities may result in take, in the form of Level A harassment 
(Dall's porpoise, harbor porpoise, and harbor seal) and Level B 
harassment from underwater sounds generated from pile driving and 
removal and tension anchoring. Potential takes could occur if 
individuals are present in the ensonified zone when these activities 
are underway.
    The takes by Level B harassment would be due to potential 
behavioral disturbance and TTS. Takes by Level A harassment would be 
due to auditory injury. No mortality or serious injury is anticipated 
given the nature of the activity, even in the absence of the required 
mitigation. The potential for harassment is minimized through the 
construction method and the implementation of the proposed mitigation 
measures (see Proposed Mitigation section).
    Take would occur within a limited, confined area (Port Fredrick) of 
the stocks' ranges. The intensity and duration of take by Level A 
harassment and Level B harassment would be minimized through use of 
mitigation measures described herein. Further, the amount of take 
proposed to be authorized is extremely small when compared to stock 
abundance, and the project is not anticipated to impact any known 
important habitat areas for any marine mammal species with the 
exception of a known biologically important area for humpback whales, 
discussed below.
    Take by Level A harassment is authorized to account for the 
potential that an animal could enter and remain within the area between 
a Level A harassment zone and the shutdown zone for a duration long 
enough to be taken by Level A harassment. Any take by Level A 
harassment is expected to arise from, at most, a small degree of 
auditory injury because animals would need to be exposed to higher 
levels and/or longer duration than are expected to occur here in order 
to incur any more than a small degree of auditory injury. Additionally, 
and as noted previously, some subset of the individuals that are 
behaviorally harassed could also simultaneously incur some small degree 
of TTS for a short duration of time. Because of the small degree 
anticipated, though, any auditory injury or TTS potentially incurred 
here would not be expected to adversely impact individual fitness, let 
alone annual rates of recruitment or survival.
    Behavioral responses of marine mammals to pile driving at the 
project site, if any, are expected to be mild and temporary. Marine 
mammals within the Level B harassment zone may not show any visual cues 
they are disturbed by activities or could become alert, avoid the area, 
leave the area, or display other mild responses that are not observable 
such as changes in vocalization patterns. Given the limited number of 
piles to be installed or extracted per day and that pile driving and 
removal would occur across a maximum of 107 days within the 12-month 
authorization period, any harassment would be temporary.
    Any impacts on marine mammal prey that would occur during Hoonah's 
proposed activity would have, at most, short-term effects on foraging 
of individual marine mammals, and likely no effect on the populations 
of marine mammals as a whole. Indirect effects on marine mammal prey 
during the construction are expected to be minor, and these effects are 
unlikely to cause substantial effects on marine mammals at the 
individual level, with no expected effect on annual rates of 
recruitment or survival.
    In addition, it is unlikely that elevated noise in a small, 
localized area of habitat would have any effect on the stocks' annual 
rates of recruitment or survival. In combination, we believe that these 
factors, as well as the available body of evidence from other similar 
activities, demonstrate that the potential effects of the specified 
activities will have only minor, short-term effects on individuals. The 
specified activities are not expected to impact rates of recruitment or 
survival, and will therefore not result in population-level impacts.
    The waters of Glacier Bay and Icy Strait are part of the Alaska 
humpback whale feeding BIA (Wild et al., 2023). However, underwater 
sound would be constrained to Port Fredrick and would be truncated by 
land masses in the inlet. The area of the BIA that may be affected

[[Page 1103]]

by the proposed project is small relative to the overall area of the 
BIA. The humpback whale feeding BIA is active between May and October 
while the proposed project is scheduled to occur between September and 
January, resulting in only 2 months of overlap. Additionally, pile 
driving associated with the project is expected to take only 107 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.
    There are two known harbor seal haulouts within Port Fredrick. One 
of the haulouts (CE79A) is located approximately 10 km (6.25 mi) from 
the project site and is outside of the ensonfied zone for this action. 
The other (CF39A) is located approximately 3 km (2 mi) from the project 
site and will be ensonified during some vibratory and impact pile 
driving activities. Neither of these haulouts are listed as a ``key 
haulout,'' or a haulout with 50 or more individuals present at the time 
of survey (AFSC 2024). Given that these are not considered key 
haulouts, and the maximum of 43 days that the ensonified zone will 
extend over 2 km, the proposed project is not expected to have 
significant adverse effects on harbor seal haulout sites. 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 
authorized;
     For all species except Dall's porpoises, harbor porpoises, 
and harbor seals, no Level A harassment is anticipated or proposed for 
this action;
     The intensity of anticipated takes by Level B harassment 
is relatively low for all stocks and would not be of a duration or 
intensity expected to result in impacts on reproduction or survival;
     The lack of anticipated significant or long-term negative 
effects to marine mammal habitat;
     With the exception of the humpback whale BIA described 
above, 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; and
     Hoonah would implement mitigation measures, such as soft-
starts for impact pile driving and shutdowns to minimize the numbers of 
marine mammals exposed to injurious levels of sound, and to ensure that 
take by Level A harassment, is at most, a small degree of auditory 
injury.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted previously, only take of small numbers of marine mammals 
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is fewer than one-third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    For all stocks, except for the Alaska stock of minke whales and the 
Alaska stock of Dall's porpoises, whose abundance estimate is unknown, 
the proposed number of takes is less than one-third of the best 
available population abundance estimate (table 8). The numbers of 
animals proposed for authorization to be taken from these stocks would 
be considered small relative to the relevant stocks' abundances, even 
if each estimated taking occurred to a new individual--an extremely 
unlikely scenario.
    Current abundance estimates of Dall's porpoises in the region are 
not available. the most recent estimate (83,400 individuals) does not 
include coastal or inland waters of southeast Alaska and is considered 
unreliable since it is based upon data collected more than 8 years ago 
(Young et al., 2023). However, given the size of the most recent 
estimate, the 83 takes of this stock proposed for authorization clearly 
represents small numbers of this stock.
    There is no current or historical estimate of the Alaska minke 
whale stock, but there are known to be over 1,000 minke whales in the 
Gulf of Alaska (Muto et al. 2018), so the 11 takes proposed for 
authorization is small relative to estimated survey abundance, even if 
each proposed take occurred to a new individual. Additionally, the 
range of the Alaska stock of minke whales is extensive, stretching from 
the Canadian Pacific coast to the Chukchi Sea, and Hoonah's proposed 
project area would impact a small portion of this range.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals would be taken relative to the population 
size of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity: (1) 
That is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    Alaska Natives have traditionally harvested subsistence resources, 
including marine mammals, in the Glacier Bay and Icy Strait for a 
millennia. Present day Hoonah is the principle village of the Huna 
tribe, and according to Ian Johnson, Hoonah Indian Association's 
Environmental Coordinator, no known marine mammal harvest takes place 
in the immediate HMIC area (Johnson 2024). Limited subsistence harvests 
of marine mammals within Port Fredrick has occurred in the past, with 
the most recent recorded/documented harvests of marine mammals in 
Hoonah in 2012. The proposed activity will take place in Port Fredrick, 
and no activities overlap with current subsistence hunting areas; 
therefore, there are no relevant subsistence uses of marine mammals 
adversely impacted by this action. The proposed project is not likely 
to

[[Page 1104]]

adversely impact the availability of any marine mammal species or 
stocks that are commonly used for subsistence purposes or to impact 
subsistence harvest of marine mammals in the region.
    Based on the description of the specified activity, the measures 
described to minimize adverse effects on the availability of marine 
mammals for subsistence purposes, and the proposed mitigation and 
monitoring measures, NMFS has preliminarily determined that there will 
not be an unmitigable adverse impact on subsistence uses from Hoonah's 
proposed activities.

Endangered Species Act

    Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.) 
requires that each Federal agency insure that any action it authorizes, 
funds, or carries out is not likely to jeopardize the continued 
existence of any endangered or threatened species or result in the 
destruction or adverse modification of designated critical habitat. To 
ensure ESA compliance for the issuance of IHAs, NMFS consults 
internally whenever we propose to authorize take for endangered or 
threatened species, in this case with the Alaska Regional Office.
    NMFS is proposing to authorize take of humpback whales (Mexico DPS) 
and Steller sea lions (western DPS), 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 will conclude the ESA consultation prior to reaching a 
determination regarding the proposed issuance of the authorization.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to Hoonah for conducting the Hoonah Cargo Dock Project in 
Hoonah, Alaska from September 1, 2025 through August 31, 2026, 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 
construction project. We also request comment on the potential renewal 
of this proposed IHA as described in the paragraph below. Please 
include with your comments any supporting data or literature citations 
to help inform decisions on the request for this IHA or a subsequent 
renewal IHA.
    On a case-by-case basis, NMFS may issue a one-time, 1-year renewal 
IHA following notice to the public providing an additional 15 days for 
public comments when (1) up to another year of identical or nearly 
identical activities as described in the Description of Proposed 
Activity section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activity section of this 
notice would not be completed by the time the IHA expires and a renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed renewal IHA effective date (recognizing that the 
renewal IHA expiration date cannot extend beyond 1 year from expiration 
of the initial IHA);
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take); 
and
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized; and
     Upon review of the request for renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: January 2, 2025.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2025-00014 Filed 1-6-25; 8:45 am]
BILLING CODE 3510-22-P
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