Notice2025-13708
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Seward Cruise Ship Passenger Dock and Terminal Facility Project in Seward, Alaska
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
July 22, 2025
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from Turnagain Marine Construction (TMC) for authorization to take marine mammals incidental to Seward Cruise Ship Passenger Dock and Terminal Facility project in Seward, Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an incidental harassment authorization (IHA) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, 1-year renewal that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorization and agency responses will be summarized in the final notice of our decision.
Full Text
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<title>Federal Register, Volume 90 Issue 138 (Tuesday, July 22, 2025)</title>
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[Federal Register Volume 90, Number 138 (Tuesday, July 22, 2025)]
[Notices]
[Pages 34463-34484]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-13708]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XE773]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Seward Cruise Ship Passenger Dock
and Terminal Facility Project in Seward, 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 Turnagain Marine Construction
(TMC) for authorization to take marine mammals incidental to Seward
Cruise Ship Passenger Dock and Terminal Facility project in Seward,
Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is
requesting comments on its proposal to issue an incidental harassment
authorization (IHA) to incidentally take marine mammals during the
specified activities. NMFS is also requesting comments on a possible
one-time, 1-year renewal that could be issued under certain
circumstances and if all requirements are met, as described in Request
for Public Comments at the end of this notice. NMFS will consider
public comments prior to making any final decision on the issuance of
the requested MMPA authorization and agency responses will be
summarized in the final notice of our decision.
DATES: Comments and information must be received no later than August
21, 2025.
[[Page 34464]]
ADDRESSES: Comments should be addressed to the Permits and Conservation
Division, Office of Protected Resources, National Marine Fisheries
Service and should be submitted via email to <a href="/cdn-cgi/l/email-protection#9fd6cbcfb1d7feedf3fefcf7faeddff1f0fefeb1f8f0e9"><span class="__cf_email__" data-cfemail="2a637e7a04624b58464b49424f586a44454b4b044d455c">[email protected]</span></a>.
Electronic copies of the application and supporting documents, as well
as a list of the references cited in this document, may be obtained
online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>. 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 <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a> 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: Jenna Harlacher, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Section 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
On October 17, 2024, NMFS received a request from TMC for an IHA to
take marine mammals incidental to Seward Cruise Ship Passenger Dock and
Terminal Facility project in Seward, Alaska. Following NMFS' review of
the application, TMC submitted a revised version on April 8, 2025. The
application was deemed adequate and complete on May 16, 2025. TMC's
request is for take of eight species of marine mammals by Level A and
Level B harassment. Neither TMC nor NMFS expect serious injury or
mortality to result from this activity and, therefore, an IHA is
appropriate.
Description of Proposed Activity
Overview
TMC is proposing to remove an existing passenger dock and replace
it with a new passenger dock at the head of Resurrection Bay in Seward,
Alaska. The existing passenger dock was constructed over 55 years ago
and needs to be replaced to maintain safety and function. The proposed
Seward Cruise Ship Passenger Dock and Terminal Facility Project
(hereafter ``project'') would provide safe harbor for cruise ships and
passengers during the visitor season and limited freight and utilities
in the off-season.
The project would include removal of the existing passenger
terminal building, passenger dock, and steel piles; dredging and
offshore disposal of dredge materials; and installing new steel piles
to support a new 300-foot (ft) (91.4-meters (m)) by 50-ft (15.2-m)
fixed dock, a new 125-ft (38.1-m) transfer bridge, and a new 780-ft
(237.7-m) by 100-ft (30.5-m) floating dock. Construction would occur on
approximately 323 non-consecutive days with pile installation and
removal occurring over 203 non-consecutive in-water work days over the
course of 1 year. The proposed activities that have the potential to
take marine mammals, by Level A and Level B harassment, include
vibratory removal of existing H and steel pipe piles, vibratory
installation and removal of temporary steel pipe piles, vibratory and
impact installation of permanent steel pipe piles, and down-the-hole
drilling (DTH) if required for installation of steel pipe piles deep
into the bedrock.
Dates and Duration
Pile installation and removal on the Passenger Dock would require
approximately 8 months beginning in fall 2025. TMC estimates a total of
203 days of in-water pile driving activity with a maximum number of 323
non-consecutive construction days. The proposed IHA would be valid for
the statutory maximum of 1 year from the date of effectiveness, and
will become effective upon written notification from the applicant to
NMFS, but not beginning later than 1 year from the date of issuance or
extending beyond 2 years from the date of issuance.
Specific Geographic Region
The proposed project is located in Seward, Alaska, on the Kenai
Peninsula at the head of Resurrection Bay. Resurrection bay is broken
into sections, the inner and outer Resurrection Bay. Outer Resurrection
Bay refers to locations that occur near the mouth of the bay and the
surrounding islands with Caine's Head dividing the inner and outer bay.
The Passenger Dock is located approximately two kilometers (km) north
of downtown Seward.
BILLING CODE 3510-22-P
[[Page 34465]]
[GRAPHIC] [TIFF OMITTED] TN22JY25.000
[[Page 34466]]
BILLING CODE 3510-22-C
Detailed Description of the Specified Activity
TMC proposes to remove the existing structure and construct a new
cruise ship dock. This proposed project would include the removal of
1,830 existing piles via vibratory removal, the installation and
removal of 100 temporary piles via vibratory driving with up to 24
piles further installed via down-the-hole drilling (DTH), and
installation of 108 permanent piles via vibratory and impact pile
driving, with up to 37 requiring further installation via DTH (see
table 1).
The existing 14-inch (in) (35.6-centimeter (cm)) h-piles and 20-in
(50.8-cm) steel piles would be removed using the deadpull method via
crane or vibratory removal if needed. Pile templates would be
constructed by vibrating temporary 36-in (91.4-cm) piles into position.
Each section of the fixed dock requires one to three temporary piles
per template. For the dolphin structure, four to six temporary piles
may be needed per template. Most temporary piles would be vibrated into
place, however, up to 24 may require additonal DTH in locations where
the bedrock is shallow. Using the templates as guides to position the
permanent piles, the permanent piles would be vibrated into dense
material, then driven to tip elevation using an impact hammer.
The 76 permanent 48-in (122-cm) steel piles supporting the fixed
dock and mooring dolphins would be vibrated below the midline, then
impacted. Up to 24 of the 48-in piles would then be drilled into the
bedrock with a DTH hammer. The 16 permanent 60-in (152-cm) and 72-in
(183-cm) steel piles would be vibrated and impacted through the soil
layer to the bedrock to support the mooring dolphins. If required, up
to eight 60-in and up to five 72-in permanent piles would then be
installed into the bedrock with DTH. All of these activities may result
in incidental take of marine mammals.
Table 1--Number and Type of Piles To Be Installed and Removed
----------------------------------------------------------------------------------------------------------------
Activity duration
Method Pile size and type (minutes (strikes)/ Max piles Number of Estimated days
pile) \1\ per day piles of work
----------------------------------------------------------------------------------------------------------------
Vibratory Pile Driving
----------------------------------------------------------------------------------------------------------------
Existing Pile removal........... 14-in H-pile....... 5 40 1,820 46
Existing Pile removal........... 20-in steel pile... 10 4 10 2.5
Temporary Pile Installation and 36-in steel pile... 10 6 100 33
Removal.
Permanent Pile Installation..... 48-in steel pile... 10 6 76 13
Permanent Pile Installation..... 60-in steel pile... 15 4 16 16
Permanent Pile Installation..... 72-in steel pile... 20 4 16 16
----------------------------------------------------------------------------------------------------------------
Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
Permanent Pile Installation..... 48-in steel pile... 3,000 4 76 19
Permanent Pile Installation..... 60-in steel pile... 3,000 3 16 16
Permanent Pile Installation..... 72-in steel pile... 3,000 3 16 16
----------------------------------------------------------------------------------------------------------------
DTH
----------------------------------------------------------------------------------------------------------------
Temporary Pile Installation..... 36-in steel pile... 120 4 24 6
Permanent Pile Installation..... 48-in steel pile... 150 4 24 6
Permanent Pile Installation..... 60-in steel pile... 240 2 8 8
Permanent Pile Installation..... 72-in steel pile... 360 2 5 5
----------------------------------------------------------------------------------------------------------------
\1\ Vibratory pile driving and DTH units are minutes per pile and Impact pile driving units are strikes per
pile.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting sections).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
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 Marine Mammal SARs. All values presented in table 2
[[Page 34467]]
are the most recent available at the time of publication (including
from the draft 2024 SARs) and are available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
Table 2--Species \1\ With Estimated Take From 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 Eschrichtiidae:
Gray Whale...................... Eschrichtius robustus.. Eastern North Pacific.. -, -, N 26,960 (0.05, 25,849, 801 131
2016).
Family Balaenopteridae (rorquals):
Fin Whale....................... Balaenoptera physalus.. Northeast Pacific...... E, D, Y 2,554 (UND, UND, 2013) UND 0.6
\5\.
Humpback Whale.................. Megaptera novaeangliae. Hawai[revaps]i \6\..... -, -, N 11,278 (0.56, 7,265, 127 27.09
2020).
Humpback Whale.................. Megaptera novaeangliae. Mexico-North Pacific... T, D, Y 918 (N/A, N/A, 2006) UND 0.57
\7\.
Humpback Whale.................. Megaptera novaeangliae. Western North Pacific.. E, D, Y 1,084 (0.088, 1,007, \8\ 3.4 5.82
2006).
--------------------------------------------------------------------------------------------------------------------------------------------------------
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) \9\.
Killer Whale.................... Orcinus orca........... AT1 Transient.......... -, D, Y 7 (N/A, 7, 2019) \10\. 0.1 0
Killer Whale.................... Orcinus orca........... Eastern North Pacific -, -, N 587 (N/A, 587, 2012) 5.9 0.8
Gulf of Alaska, \11\.
Aleutian Islands and
Bering Sea Transient.
Family Phocoenidae (porpoises):
Dall's Porpoise................. Phocoenoides dalli..... Alaska................. -, -, N UND (UND, UND, 2015) UND 37
\12\.
Harbor Porpoise................. Phocoena phocoena...... Gulf of Alaska......... -, -, Y 31,046 (0.21, N/A, UND 72
1998).
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Order Carnivora--Pinnipedia
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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) \13\.
Family Phocidae (earless seals):
Harbor Seal..................... Phoca vitulina......... Prince William Sound... -, -, N 44,756 (N/A, 41,776, 1,253 413
2015).
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\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>; Committee on Taxonomy, 2022).
\2\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or
which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is
automatically designated under the MMPA as depleted and as a strategic stock.
\3\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region</a>. 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\ The best available abundance estimate for this stock is not considered representative of the entire stock as surveys were limited to a small portion
of the stock's range. Based upon this estimate and the Nmin, the PBR value is likely negatively biased for the entire stock.
\6\ New SAR in 2022 following North Pacific humpback whale stock structure changes.
\7\ Abundance estimates are based upon data collected more than 8 years ago and, therefore, current estimates are considered unknown.
\8\ PBR in U.S. waters = 0.2, M/SI in U.S. waters = 0.06.
\9\ Nest is based upon counts of individuals identified from photo-ID catalogs.
\10\ Nest is based upon counts of individuals identified from photo-ID catalogs. PBR has been calculated, however, a reliable estimate of the maximum
net productivity rate is not available for this stock, and the default cetacean maximum theoretical net productivity rate was used for the PBR
calculation.
\11\ Nest is based upon counts of individuals identified from photo-ID catalogs.
\12\ 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.
\13\ 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.
As indicated above, all eight 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. While sperm whales
(Physeter macrocephalus), eastern U.S. Steller sea lions, North Pacific
right whales (Eubalaena japonica), minke whales (Balaenoptera
acutorostrata), Pacific white-sided dolphin (Lagenorhynchus
obliquidens), northern fur seal (Callorhinus ursinus), and northern
elephant seal (Mirounga angustirostris) are included in the application
and are found in the area, these species do not commonly occur inside
Resurrection Bay. Thus, 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.
In addition, northern sea otters (Enhydra lutris) may be found in
Seward, Alaska. However, sea otters are managed by the U.S. Fish and
Wildlife Service and are not considered further in this document.
In addition to what is included in sections 3 and 4 of the IHA
application, and NMFS' website, further detail informing our analysis
on the regional occurrence for select species of particular or unique
vulnerability (i.e., information regarding ESA listed species) is
provided below.
[[Page 34468]]
Fin Whale
Fin whales are found in the Gulf of Alaska year-round. They
typically inhabit deep, offshore waters, but a portion of the northeast
Pacific stock (ESA-endangered) habitually utilizes inshore waters of
the Kitimat Fjord System in coastal British Columbia, Canada; and fin
whales have occasionally been observed in inside waters of southeast
Alaska and Prince William Sound (Keen et al., 2018; Ferguson et al.,
2015).
Local sightings from whale watching tours and Alaska Sea Life
Center indicate that fin whales are frequently sighted in outer
Resurrection bay. Additionally, Kenai Fjords National park staff
monitor for fin whales and state that the area between the end of
Resurrection Peninsula and Cheval Island and Agnes Cove (38 km from the
project area) is a hot spot for fin whales (National Park Service,
2018). Although fin whales are most commonly sighted in outer
Resurrection Bay, available occurrence data from the Global
Biodiversity Information Facility (GBIF) show that fin whales have been
observed as far into Resurrection Bay as the northern tip of Fox Island
(GBIF, 2022), with reported sightings in inner Resurrection Bay in
2019, 2023, and 2024 (GBIF, 2024). There are no designated critical
habitats for fin whales and there are no known biologically important
areas for this species in the action area.
Humpback Whale
Three stocks of humpback whales could be found in the project area.
These include the Hawai[revaps]i Stock (not ESA-listed), Mexico-North
Pacific Stock (ESA-threatened), and the western North Pacific Stock
(ESA-endangered). Although humpbacks seasonally migrate, they are
observed in inner and outer Resurrection Bay regularly throughout the
summer season (May through August) and may venture into the outer bay
year-round (McCaslin, 2019; GBIF, 2022a). There are no designated
critical habitats or biologically important areas for humpback whales
in the action area.
Killer Whale
Three stocks of killer whales that are most likely to occur in
Southcentral Alaska and the project area are the Alaska Resident stock,
Gulf of Alaska/Aleutian Islands/Bering Sea Transient stock, and the AT1
Transient stock, listed as depleted under the MMPA (Muto et al. 2022).
The Alaska Resident stock occurs from Southeast Alaska to the Aleutian
Islands and Bering Sea. The Gulf of Alaska/Aleutian Islands/Bering Sea
Transient stock range from Prince William Sound through the Aleutian
Islands and Bering Sea. The AT1 Transient Stock, can be found from
Prince William Sound to Kenai Fjords (Muto et al. 2022).
The AT1 Transient stock's primary habitat includes Resurrection
Bay. The AT1 Transient stock experienced high mortality following the
Exxon Valdez oil spill, as 11 of the original 22 individuals
disappeared between 1989 and 1992. The AT1 stock currently numbers only
seven individuals (Muto et al., 2022).
Consultation with the Alaska SeaLife Center indicated that killer
whales are commonly sighted year-round in inner and outer Resurrection
Bay (Alaska SeaLife Center 2024). Local NPS reports that both resident
and transient populations are frequently observed in Kenai Fjords.
Steller Sea Lion
Only the western stock (ESA- endangered) of Steller sea lion is
likely to occur in the action area. Womble et al. (2009) characterized
Steller sea lion distribution in southeast Alaska in relation to
seasonally available prey resources. Womble et al. identified four
types of seasonal haulouts based on prey type and Resurrection Bay is
characteristic of all four site types (ADF&G, 2022a; Brown et al.,
2002). The year-round availability of prey resources in Resurrection
Bay (especially at the head of the bay) make it excellent foraging
habitat for Steller sea lions.
It is anticipated that Steller sea lions would be present in the
range of the project area year-round, with fewer individuals during the
breeding season (late May through early June) when breeding females and
mature males congregate at rookeries.
Reports from professional tour boat captains based in Seward
indicate that at least 5 to 10 Steller sea lions can be found foraging
daily throughout inner Resurrection Bay, often near Seward Harbor.
Other areas where Steller sea lions are commonly observed within inner
Resurrection Bay include Lowell Point, Tonsina Point, and Fourth of
July Beach.
The proposed action does not overlap with Steller sea lion critical
habitat or any major haulouts and rookeries; however, critical habitat
occurs immediately outside of Resurrection Bay in close proximity to
the ensonified area. The closest major haulouts to the action are at
the mouth of Resurrection Bay, on the Resurrection Peninsula
(approximately 20.95 kilometers (km) from the project site) and on Hive
Island (25.72 km from the project site). The closest Steller sea lion
rookery is the Chiswell Islands (approximately 54 km from the project
site). Although the ensonified area extends out to 24 km from the pile
driving location, due to directionality and land masses it does not
overlap with any critical habitat surrounding these haulouts.
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, 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 table 3.
Table 3--Marine Mammal Hearing Groups
[NMFS, 2024]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 36 kHz.
whales).
High-frequency (HF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
[[Page 34469]]
Very High-frequency (VHF) cetaceans 200 Hz to 165 kHz.
(true porpoises, Kogia, river
dolphins, Cephalorhynchid,
Lagenorhynchus cruciger & L.
australis).
Phocid pinnipeds (PW) (underwater) 40 Hz to 90 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 68 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges may not be as broad. Generalized hearing range
chosen based on ~65 dB threshold from composite audiogram, previous
analysis in NMFS (2018), and/or data from Southall et al. (2007,
2019). Additionally, animals are able to detect very loud sounds above
and below that ``generalized'' hearing range.
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2024) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take of Marine Mammals section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take of Marine Mammals section, and the Proposed Mitigation
section, to draw conclusions regarding the likely impacts of these
activities on the reproductive success or survivorship of individuals
and whether those impacts are reasonably expected to, or reasonably
likely to, adversely affect the species or stock through effects on
annual rates of recruitment or survival.
Acoustic effects on marine mammals during the specified activity
can occur from impact and vibratory pile driving. The effects of
underwater noise from TMC's proposed activities have the potential to
result in Level A or Level B harassment of marine mammals in the action
area.
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 vibratory pile removal, impact and vibratory pile driving, and
DTH. The sounds produced by these activities fall into one of two
general sound types: impulsive and non-impulsive. Impulsive sounds
(e.g., explosions, gunshots, sonic booms, impact pile driving) are
typically transient, brief (less than 1 second), broadband, and consist
of high peak sound pressure with rapid rise time and rapid decay (ANSI,
1986; NIOSH, 1998; ANSI, 2005; NMFS, 2018a). Non-impulsive sounds
(e.g., aircraft, machinery operations such as drilling or dredging,
vibratory pile driving, and active sonar systems) can be broadband,
narrowband or tonal, brief or prolonged (continuous or intermittent),
and typically do not have the high peak sound pressure with raid rise/
decay time that impulsive sounds do (ANSI, 1995; NIOSH, 1998; NMFS,
2018a). The distinction between these two sound types is important
because they have differing potential to cause physical effects,
particularly with regard to hearing (e.g., Ward 1997 in Southall et
al., 2007).
TMC proposes to use vibratory hammers to remove steel piles,
vibratory and impact pile driving to install new steel pipe piles, and
DTH for a subset of installed piles to reach full depth. Impact hammers
operate by repeatedly dropping a heavy piston onto a pile to drive the
pile into the substrate. Sound generated by impact hammers is
characterized by rapid rise times and high peak levels, a potentially
injurious combination (Hastings and Popper, 2005). Vibratory hammers
install piles by vibrating them and allowing the weight of the hammer
to push them into the sediment. Vibratory hammers produce significantly
less sound than impact hammers. Peak sound pressure levels (SPLs) may
be 180 dB or greater, but are generally 10 to 20 dB lower than SPLs
generated during impact pile driving of the same-sized pile (Oestman et
al., 2009). Rise time is slower, reducing the probability and severity
of injury, and sound energy is distributed over a greater amount of
time (Nedwell and Edwards, 2002; Carlson et al., 2005).
A DTH hammer is essentially a drill bit that drills through the
bedrock using a rotating function like a normal drill, in concert with
a hammering mechanism operated by a pneumatic (or sometimes hydraulic)
component integrated into the DTH hammer to increase speed of progress
through the substrate (i.e., it is similar to a ``hammer drill'' hand
tool). The sounds produced by the DTH method contain both a continuous
non-impulsive component from the drilling action and an impulsive
component from the hammering effect. Therefore, we treat DTH systems as
both impulsive and non-impulsive sound source types simultaneously.
[[Page 34470]]
The likely or possible impacts of TMC's proposed activity on marine
mammals could involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of equipment and personnel; however, any impacts to marine
mammals are expected to be primarily acoustic in nature. Acoustic
stressors include effects of heavy equipment operation during pile
installation and removal.
Acoustic Effects
The introduction of anthropogenic noise into the aquatic
environment from pile driving and removal is the means by which marine
mammals may be harassed from TMC's specified activity. In general,
animals exposed to natural or anthropogenic sound may experience
behavioral, physiological, and/or physical effects, ranging in
magnitude from none to severe (Southall et al., 2007, 2019). In
general, exposure to pile driving noise has the potential to result in
behavioral reactions (e.g., avoidance, temporary cessation of foraging
and vocalizing, changes in dive behavior) and, in limited cases, an
auditory threshold shift (TS). Exposure to anthropogenic noise can also
lead to non-observable physiological responses such an increase in
stress hormones. Additional noise in a marine mammal's habitat can mask
acoustic cues used by marine mammals to carry out daily functions such
as communication and predator and prey detection. The effects of pile
driving noise on marine mammals are dependent on several factors,
including, but not limited to, sound type (e.g., impulsive vs. non-
impulsive), the species, age and sex class (e.g., adult male vs. mom
with calf), duration of exposure, the distance between the pile and the
animal, received levels, behavior at time of exposure, and previous
history with exposure (Wartzok et al., 2004; Southall et al., 2007).
Here we discuss physical auditory effects (TSs) followed by behavioral
effects and potential impacts on habitat.
NMFS defines a noise-induced TS as a change, usually an increase,
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS, 2018, 2024). The amount of TS is customarily expressed in
dB. A TS can be permanent or temporary. As described in NMFS (2018,
2024), there are numerous factors to consider when examining the
consequence of TS, including, but not limited to, the signal temporal
pattern (e.g., impulsive or non-impulsive), likelihood an individual
would be exposed for a long enough duration or to a high enough level
to induce a TS, the magnitude of the TS, time to recovery (seconds to
minutes or hours to days), the frequency range of the exposure (i.e.,
spectral content), the hearing and vocalization frequency range of the
exposed species relative to the signal's frequency spectrum (i.e., how
animal uses sound within the frequency band of the signal; e.g.,
Kastelein et al., 2014), and the overlap between the animal and the
source (e.g., spatial, temporal, and spectral).
Auditory Injury (AUD INJ) and Permanent Threshold Shift (PTS)--NMFS
defines AUD INJ as ``damage to the inner ear that can result in
destruction of tissue . . . which may or may not result in PTS'' (NMFS,
2024). NMFS defines PTS as a permanent, irreversible increase in the
threshold of audibility at a specified frequency or portion of an
individual's hearing range above a previously established reference
level (NMFS, 2024). PTS does not generally affect more than a limited
frequency range, and an animal that has incurred 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)--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), 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 (SEL<INF>cum</INF>) in an accelerating fashion: At
low exposures with lower SEL<INF>cum</INF>, the amount of TTS is
typically small and the growth curves have shallow slopes. At exposures
with higher SEL<INF>cum</INF>, the growth curves become steeper and
approach linear relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in the Masking
section, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Many studies have examined noise-induced hearing loss in marine
mammals (see Finneran (2015) and Southall et al. (2019) for summaries).
TTS is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter, 2013). While experiencing TTS, the hearing
threshold rises, and a sound must be at a higher level in order to be
heard. In terrestrial and marine mammals, TTS can last from minutes or
hours to days (in cases of strong TTS). In many cases, hearing
sensitivity recovers rapidly after exposure to the sound ends. For
cetaceans, published data on the onset of TTS are limited to captive
bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis) (Southall et al., 2019). For pinnipeds in water,
measurements of TTS are limited to harbor seals, elephant seals,
bearded seals (Erignathus barbatus) and California sea lions (Zalophus
californianus) (Kastak et al., 1999, 2007; Kastelein et al., 2019b,
2019c, 2021, 2022a, 2022b; Reichmuth et al., 2019; Sills et al., 2020).
TTS was not observed in spotted (Phoca largha) and ringed (Pusa
hispida) seals exposed to single airgun impulse sounds at levels
matching previous predictions of TTS
[[Page 34471]]
onset (Reichmuth et al., 2016). These studies examine hearing
thresholds measured in marine mammals before and after exposure to
intense or long-duration sound exposures. The difference between the
pre-exposure and post-exposure thresholds can be used to determine the
amount of threshold shift at various post-exposure times.
The amount and onset of TTS depends on the exposure frequency.
Sounds at low frequencies, well below the region of best sensitivity
for a species or hearing group, are less hazardous than those at higher
frequencies, near the region of best sensitivity (Finneran and
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are
higher compared to those in the region of best sensitivity (i.e., a low
frequency noise would need to be louder to cause TTS onset when TTS
exposure level is higher), as shown for harbor porpoises and harbor
seals (Kastelein et al., 2019a, 2019c). Note that in general, harbor
seals and harbor porpoises have a lower TTS onset than other measured
pinniped or cetacean species (Finneran, 2015). In addition, TTS can
accumulate across multiple exposures, but the resulting TTS would be
less than the TTS from a single, continuous exposure with the same SEL
(Mooney et al., 2009; Finneran et al., 2010; Kastelein et al., 2014,
2015). This means that TTS predictions based on the total, cumulative
SEL would overestimate the amount of TTS from intermittent exposures,
such as sonars and impulsive sources. Nachtigall et al. (2018) describe
measurements of hearing sensitivity of multiple odontocete species
(bottlenose dolphin, harbor porpoise, beluga, and false killer whale
(Pseudorca crassidens)) when a relatively loud sound was preceded by a
warning sound. These captive animals were shown to reduce hearing
sensitivity when warned of an impending intense sound. Based on these
experimental observations of captive animals, the authors suggest that
wild animals may dampen their hearing during prolonged exposures or if
conditioned to anticipate intense sounds. Another study showed that
echolocating animals (including odontocetes) might have anatomical
specializations that might allow for conditioned hearing reduction and
filtering of low-frequency ambient noise, including increased stiffness
and control of middle ear structures and placement of inner ear
structures (Ketten et al., 2021). Data available on noise-induced
hearing loss for mysticetes are currently lacking (NMFS, 2018).
Additionally, the existing marine mammal TTS data come from a limited
number of individuals within these species.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals, and there is no PTS data for cetaceans, but such
relationships are assumed to be similar to those in humans and other
terrestrial mammals. PTS typically occurs at exposure levels at least
several decibels above that inducing mild TTS (e.g., a 40-dB threshold
shift approximates PTS onset (Kryter et al., 1966; Miller, 1974), while
a 6-dB threshold shift approximates TTS onset (Southall et al., 2007,
2019). Based on data from terrestrial mammals, a precautionary
assumption is that the PTS thresholds for impulsive sounds (such as
impact pile driving pulses as received close to the source) are at
least 6 dB higher than the TTS threshold on a peak-pressure basis and
PTS cumulative sound exposure level thresholds are 15 to 20 dB higher
than TTS cumulative sound exposure level thresholds (Southall et al.,
2007, 2019). Given the higher level of sound or longer exposure
duration necessary to cause PTS as compared with TTS, it is
considerably less likely that PTS could occur.
Activities for this project include impact pile driving, vibratory
pile driving and vibratory removal, and DTH. There would likely be
pauses in activities producing the sound during each day. Given these
pauses and the fact that many marine mammals are likely moving through
the project areas and not remaining for extended periods of time, the
potential for TS declines.
Behavioral Harassment--Exposure to noise from pile driving also has
the potential to behaviorally disturb marine mammals. Generally
speaking, NMFS considers a behavioral disturbance that rises to the
level of harassment under the MMPA a non-minor response--in other
words, not every response qualifies as behavioral disturbance, and for
responses that do, those of a higher level, or accrued across a longer
duration, have the potential to affect foraging, reproduction, or
survival. Behavioral disturbance may include a variety of effects,
including subtle changes in behavior (e.g., minor or brief avoidance of
an area or changes in vocalizations), more conspicuous changes in
similar behavioral activities, and more sustained and/or potentially
severe reactions, such as displacement from or abandonment of high-
quality habitat. Behavioral responses may include changing durations of
surfacing and dives, changing direction and/or speed; reducing/
increasing vocal activities; changing/cessation of certain behavioral
activities (such as socializing or feeding); eliciting a visible
startle response or aggressive behavior (such as tail/fin slapping or
jaw clapping); avoidance of areas where sound sources are located.
Pinnipeds may increase their haul out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006).
Behavioral responses to sound are highly variable and context-
specific and any reactions depend on numerous intrinsic and extrinsic
factors (e.g., species, state of maturity, experience, current
activity, reproductive state, auditory sensitivity, time of day), as
well as the interplay between factors (e.g., Richardson et al., 1995;
Wartzok et al., 2004; Southall et al., 2007, 2019; Weilgart, 2007;
Archer et al., 2010). Behavioral reactions can vary not only among
individuals but also within an individual, depending on previous
experience with a sound source, context, and numerous other factors
(Ellison et al., 2012), and can vary depending on characteristics
associated with the sound source (e.g., whether it is moving or
stationary, number of sources, distance from the source). In general,
pinnipeds seem more tolerant of, or at least habituate more quickly to,
potentially disturbing underwater sound than do cetaceans, and
generally seem to be less responsive to exposure to industrial sound
than most cetaceans. Please see Appendices B and C of Southall et al.
(2007) and Gomez et al. (2016) for reviews of studies involving marine
mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2004). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure.
As noted above, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; Wartzok et al., 2004; National
[[Page 34472]]
Research Council (NRC), 2005). Controlled experiments with captive
marine mammals have showed pronounced behavioral reactions, including
avoidance of loud sound sources (Ridgway et al., 1997; Finneran et al.,
2003). Observed responses of wild marine mammals to loud pulsed sound
sources (e.g., seismic airguns) have been varied but often consist of
avoidance behavior or other behavioral changes (Richardson et al.,
1995; Morton and Symonds, 2002; Nowacek et al., 2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et
al., 2004; Goldbogen et al., 2013a, 2013b). Variations in dive behavior
may reflect interruptions in biologically significant activities (e.g.,
foraging) or they may be of little biological significance. The impact
of an alteration to dive behavior resulting from an acoustic exposure
depends on what the animal is doing at the time of the exposure and the
type and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. However, acoustic and movement bio-logging tools have been
used in some cases, to infer responses of feeding to anthropogenic
noise. For example, Blair et al. (2016) reported significant effects on
humpback whale foraging behavior in Stellwagen Bank in response to ship
noise including slower descent rates, and fewer side-rolling events per
dive with increasing ship nose. In addition, Wisniewska et al. (2018)
reported that tagged harbor porpoises demonstrated fewer prey capture
attempts when encountering occasional high-noise levels resulting from
vessel noise as well as more vigorous fluking, interrupted foraging,
and cessation of echolocation signals observed in response to some
high-noise vessel passes.
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
relationships among prey availability, foraging effort and success, and
the life history stage(s) of the animal.
Variations in respiration naturally vary with different behaviors
and alterations to breathing rate as a function of acoustic exposure
can be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response. Various studies have shown that respiration rates may
either be unaffected or could increase, depending on the species and
signal characteristics, again highlighting the importance in
understanding species differences in the tolerance of underwater noise
when determining the potential for impacts resulting from anthropogenic
sound exposure (e.g., Kastelein et al., 2001, 2005, 2006; Gailey et
al., 2007). For example, harbor porpoise respiration rate increased in
response to pile driving sounds at and above a received broadband SPL
of 136 dB (zero-peak SPL: 151 dB (referenced to 1 micropascal (re 1
[mu]Pa)); SEL of a single strike: 127 dB re 1 [mu]Pa\2\ -s) (Kastelein
et al., 2013).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
are known to change direction--deflecting from customary migratory
paths--in order to avoid noise from seismic surveys (Malme et al.,
1984). Avoidance may be short-term, with animals returning to the area
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996;
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007).
Longer-term displacement is possible, however, which may lead to
changes in abundance or distribution patterns of the affected species
in the affected region if habituation to the presence of the sound does
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann
et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996; Bowers et al., 2018). The result of a flight response
could range from brief, temporary exertion and displacement from the
area where the signal provokes flight to, in extreme cases, marine
mammal strandings (England et al., 2001). However, it should be noted
that response to a perceived predator does not necessarily invoke
flight (Ford and Reeves, 2008), and whether individuals are solitary or
in groups may influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fishes and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction
[[Page 34473]]
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.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than 1 day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive (i.e., meaningful) behavioral reactions and multi-day
anthropogenic activities. For example, just because an activity lasts
for multiple days does not necessarily mean that individual animals are
either exposed to activity-related stressors for multiple days or,
further, exposed in a manner resulting in sustained multi-day
substantive behavioral responses.
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 would last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker, 2000;
Romano et al., 2002b) and, more rarely, studied in wild populations
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found
that noise reduction from reduced ship traffic in the Bay of Fundy was
associated with decreased stress in North Atlantic right whales. These
and other studies lead to a reasonable expectation that some marine
mammals would experience physiological stress responses upon exposure
to acoustic stressors and that it is possible that some of these would
be classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2003), however
distress is an unlikely result of this project based on observations of
marine mammals during previous, similar projects in the area.
Auditory Masking--Since many marine mammals rely on sound to find
prey, moderate social interactions, and facilitate mating (Tyack,
2008), noise from anthropogenic sound sources can interfere with these
functions, but only if the noise spectrum overlaps with the hearing
sensitivity of the receiving marine mammal (Southall et al., 2007;
Clark et al., 2009; Hatch et al., 2012). Chronic exposure to excessive,
though not high-intensity, noise could cause masking at particular
frequencies for marine mammals that utilize sound for vital biological
functions (Clark et al., 2009). Acoustic masking is when other noises
such as from human sources interfere with an animal's ability to
detect, recognize, or discriminate between acoustic signals of interest
(e.g., those used for intraspecific communication and social
interactions, prey detection, predator avoidance, navigation)
(Richardson et al., 1995; Erbe et al., 2016). Therefore, under certain
circumstances, marine mammals whose acoustical sensors or environment
are being severely masked could also be impaired from maximizing their
performance fitness in survival and reproduction. The ability of a
noise source to mask biologically important sounds depends on the
characteristics of both the noise source and the signal of interest
(e.g., signal-to-noise ratio, temporal variability, direction), in
relation to each other and to an animal's hearing abilities (e.g.,
sensitivity, frequency range, critical ratios, frequency
discrimination, directional discrimination, age or TTS hearing loss),
and existing ambient noise and propagation conditions (Hotchkin and
Parks, 2013).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003) or vocalizations (Foote et al., 2004),
respectively, while North Atlantic right whales (Eubalaena glacialis)
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007). Fin whales have also been documented
lowering the bandwidth, peak frequency, and center frequency of their
vocalizations under increased levels of background noise from large
vessels (Castellote et al., 2012). Other alterations to communication
signals have also been observed. For example, gray whales, in response
to playback experiments exposing them to vessel noise, have been
observed increasing their vocalization rate and producing louder
signals at times of increased outboard engine noise (Dahlheim and
Castellote, 2016). Alternatively, animals may cease
[[Page 34474]]
sound production during production of aversive signals (Bowles et al.,
1994).
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is human-made, it may be considered
harassment when disrupting or altering critical behaviors. It is
important to distinguish TTS and PTS, which persist after the sound
exposure, from masking, which occurs during the sound exposure. Because
masking (without resulting in TS) is not associated with abnormal
physiological function, it is not considered a physiological effect,
but rather a potential behavioral effect (though not necessarily one
that would be associated with harassment).
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al., 2000;
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2010; Holt
et al., 2009). Masking can be reduced in situations where the signal
and noise come from different directions (Richardson et al., 1995),
through amplitude modulation of the signal, or through other
compensatory behaviors (Hotchkin and Parks, 2013). Masking can be
tested directly in captive species (e.g., Erbe, 2008), but in wild
populations it must be either modeled or inferred from evidence of
masking compensation. There are few studies addressing real-world
masking sounds likely to be experienced by marine mammals in the wild
(e.g., Branstetter et al., 2013).
Marine mammals at or near the proposed TMC project site may be
exposed to anthropogenic noise which may be a source of masking.
Vocalization changes may result from a need to compete with an increase
in background noise and include increasing the source level, modifying
the frequency, increasing the call repetition rate of vocalizations, or
ceasing to vocalize in the presence of increased noise (Hotchkin and
Parks, 2013). For example, in response to loud noise, beluga whales may
shift the frequency of their echolocation clicks to prevent masking by
anthropogenic noise (Tyack, 2000; Eickmeier and Vallarta, 2022).
Masking occurs in the frequency band or bands that animals utilize
and is more likely to occur in the presence of broadband, relatively
continuous noise sources such as vibratory pile driving. Energy
distribution of pile driving covers a broad frequency spectrum, and
sound from pile driving would be within the audible range of pinnipeds
and cetaceans present in the proposed action area. While some
construction during the TMC's activities may mask some acoustic signals
that are relevant to the daily behavior of marine mammals, the short-
term duration and limited areas affected make it very unlikely that the
fitness of individual marine mammals would be impacted.
Airborne Acoustic Effects--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving
or DTH that have the potential to cause behavioral harassment,
depending on their distance from the activities. Cetaceans are not
expected to be exposed to airborne sounds that would result in
harassment as defined under the MMPA.
Airborne noise would primarily be an issue for pinnipeds that are
swimming or hauled out near the project site within the range of noise
levels elevated above the airborne acoustic harassment criteria. We
recognize that pinnipeds in the water could be exposed to airborne
sound that may result in behavioral harassment when swimming with their
heads above water. Most likely, airborne sound would cause behavioral
responses similar to those discussed above in relation to underwater
sound. For instance, anthropogenic sound could cause hauled-out
pinnipeds to exhibit changes in their normal behavior, such as
reduction in vocalizations, or cause them to temporarily abandon the
area and move further from the source. However, these animals would
previously have been `taken' because of exposure to underwater sound
above the behavioral harassment thresholds, which are in all cases
larger than those associated with airborne sound. Thus, the behavioral
harassment of these animals is already accounted for in these estimates
of potential take. Therefore, we do not believe that authorization of
incidental take resulting from airborne sound for pinnipeds is
warranted, and airborne sound is not discussed further.
Marine Mammal Habitat Effects
The project would occur near an active marine commercial and
industrial area. Construction activities at the Seward Cruise Ship
Passenger Dock and Terminal Facility project could have localized,
temporary impacts on marine mammal habitat and their prey by increasing
in-water SPLs and slightly decreasing water quality. Increased noise
levels may affect acoustic habitat (see Auditory Masking discussion
above) and adversely affect marine mammal prey in the vicinity of the
project area (see discussion below). During in-water vibratory and
impact pile driving and DTH, elevated levels of underwater noise would
ensonify a portion of Resurrection Bay, where both fish and some
mammals occur and could affect foraging success. Additionally, marine
mammals may avoid the area during construction; however, displacement
due to noise is expected to be temporary and is not expected to result
in long-term effects to the individuals or populations.
Water Quality--Temporary and localized reduction in water quality
would occur as a result of in-water construction activities. Most of
this effect would occur during the installation and removal of piles
when bottom sediments are disturbed. The installation and removal of
piles would disturb bottom sediments and may cause a temporary increase
in suspended sediment in the project area. During pile removal,
sediment attached to the pile moves vertically through the water column
until gravitational forces cause it to slough off under its own weight.
The small resulting sediment plume is expected to settle out of the
water column within a few hours. Studies of the effects of turbid water
on fish (marine mammal prey) suggest that concentrations of suspended
sediment can reach thousands of milligrams per liter before an acute
toxic reaction is expected (Burton, 1993).
Effects to turbidity and sedimentation are expected to be short-
term, minor, and localized. Suspended sediments in the water column
should dissipate and quickly return to background levels in all
construction scenarios. Turbidity within the water column has the
potential to reduce the level of oxygen in the water and irritate the
gills of prey fish species in the proposed project area. However,
turbidity plumes associated with the project would be temporary and
localized, and fish in the proposed project area would be able to move
away from and avoid the areas where plumes may occur. Therefore, it is
expected that the impacts on prey fish
[[Page 34475]]
species from turbidity, and therefore on marine mammals, would be
minimal and temporary. In general, the area likely impacted by the
proposed construction activities is relatively small compared to the
available marine mammal habitat in the Gulf of Alaska, and does not
include any areas of particular importance.
In-Water Construction Effects on Potential Prey--Sound may affect
marine mammals through impacts on the abundance, behavior, or
distribution of prey species (e.g., crustaceans, cephalopods, fish,
zooplankton). Marine mammal prey varies by species, season, and
location and, for some, is not well documented. Here, we describe
studies regarding the effects of noise on known marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009).
Depending on their hearing anatomy and peripheral sensory structures,
which vary among species, fishes hear sounds using pressure and
particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds which are especially strong and/or
intermittent low-frequency sounds, and behavioral responses such as
flight or avoidance are the most likely effects. Short duration, sharp
sounds can cause overt or subtle changes in fish behavior and local
distribution. The reaction of fish to noise depends on the
physiological state of the fish, past exposures, motivation (e.g.,
feeding, spawning, migration), and other environmental factors.
Hastings and Popper (2005) identified several studies that suggest fish
may relocate to avoid certain areas of sound energy. Additional studies
have documented effects of pile driving on fish, although several are
based on studies in support of large, multiyear bridge construction
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings,
2009). Several studies have demonstrated that impulse sounds might
affect the distribution and behavior of some fishes, potentially
impacting foraging opportunities or increasing energetic costs (e.g.,
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al.,
1992; Santulli et al., 1999; Paxton et al., 2017). However, some
studies have shown no or slight reaction to impulse sounds (e.g., Pena
et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott
et al., 2012). More commonly, though, the impacts of noise on fish are
temporary.
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function likely is
restored when damaged cells are replaced with new cells. Halvorsen et
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours
for one species. Impacts would be most severe when the individual fish
is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012b; Casper et al., 2013).
The greatest potential impact to fishes during construction would
occur during unattenuated impact pile installation of 48, 60 and 72-in
steel pipe piles, which is estimated to occur on up to 51 days for a
maximum of 4 piles per day. In-water construction activities would only
occur during daylight hours, allowing fish to forage and transit the
project area in the evening. Vibratory pile driving would possibly
elicit behavioral reactions from fishes such as temporary avoidance of
the area but is unlikely to cause injuries to fishes or have persistent
effects on local fish populations. Construction also would have minimal
permanent and temporary impacts on benthic invertebrate species, a
marine mammal prey source. In addition, it should be noted that the
area in question is low-quality habitat since it is already highly
developed and experiences a high level of anthropogenic noise from
normal operations and other vessel traffic. In general, any negative
impacts on marine mammal prey species are expected to be minor and
temporary.
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 most likely impact to fish from pile driving activities in the
project area would be temporary behavioral avoidance of the area. The
duration of fish avoidance of an area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution and
behavior is anticipated. In general, impacts to marine mammal prey
species are expected to be minor and temporary due to the expected
short daily duration of individual pile driving events.
In-Water Construction Effects on Potential Foraging Habitat--The
area likely impacted by the project is relatively small compared to the
available habitat in the Gulf of Alaska and does not include any
biologically important areas (BIAs) or ESA-designated critical habitat.
The total area affected by pile installation and removal and the new
footprint is small compared to the vast foraging area available to
marine mammals in the area. Pile driving and removal at the project
site would not obstruct long-term movements or migration of marine
mammals.
Avoidance by potential prey (i.e., fish) of the immediate area due
to the temporary loss of this foraging habitat is also possible. The
duration of fish and marine mammal avoidance of this area after pile
driving stops is unknown, but a rapid return to normal recruitment,
distribution, and behavior is anticipated. Any behavioral avoidance by
fish or marine mammals of the disturbed area would still leave
significantly large areas of fish and marine mammal foraging habitat in
the nearby vicinity.
In summary, given the short daily duration of sound associated with
individual pile driving events and the relatively small areas being
affected, pile driving activities associated with the proposed action
are not likely to have a permanent adverse effect on any fish habitat,
or populations of fish species. Any behavioral avoidance by fish of the
disturbed area would still leave significantly large areas of fish and
marine mammal foraging habitat in the nearby vicinity. Thus, we
conclude that impacts of the specified activity are not likely to have
more than short-term adverse effects on any prey habitat or populations
of prey species. Further, any impacts to marine mammal habitat are not
expected to result in significant
[[Page 34476]]
or long-term consequences for individual marine mammals, or to
contribute to adverse impacts on their populations.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
proposed for authorization through the IHA, which will inform NMFS'
consideration of ``small numbers,'' the negligible impact
determinations, and impacts on subsistence uses.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would primarily be by Level B harassment, as use
of the acoustic source (i.e., pile driving) has the potential to result
in disruption of behavioral patterns for individual marine mammals.
There is also some potential for AUD INJ (Level A harassment) to
result, for all species because predicted AUD INJ zones are large for
impact pile driving and DTH activities. The proposed mitigation and
monitoring measures are expected to minimize the severity of the taking
to the extent practicable.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic criteria above which NMFS believes the best
available science indicates marine mammals would likely be behaviorally
harassed or incur some degree of AUD INJ; (2) the area or volume of
water that would be ensonified above these levels in a day; (3) the
density or occurrence of marine mammals within these ensonified areas;
and, (4) the number of days of activities. We note that while these
factors can contribute to a basic calculation to provide an initial
prediction of potential takes, additional information that can
qualitatively inform take estimates is also sometimes available (e.g.,
previous monitoring results or average group size). Below, we describe
the factors considered here in more detail and present the proposed
take estimates.
Acoustic Criteria
NMFS recommends the use of acoustic criteria that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur AUD INJ of some degree (equated to
Level A harassment). We note that the criteria for AUD INJ, as well as
the names of two hearing groups, have been recently updated (NMFS,
2024) as reflected below in the Level A Harassment section.
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021; Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced
to 1 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.
TMC includes the use of continuous (vibratory pile driving and DTH)
and impulsive (DTH and impact pile driving) sources, and therefore the
RMS SPL thresholds of 120 and 160 dB re 1 [mu]Pa are applicable.
Level A harassment--NMFS' Updated Technical Guidance for Assessing
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version
3.0) (Updated Technical Guidance, 2024) identifies dual criteria to
assess AUD INJ (Level A harassment) to five different underwater marine
mammal groups (based on hearing sensitivity) as a result of exposure to
noise from two different types of sources (impulsive or non-impulsive).
TMC's proposed activity includes the use of impulsive (DTH and impact
pile driving) and non-impulsive (vibratory pile driving and DTH)
sources.
The 2024 Updated Technical Guidance criteria include both updated
thresholds and updated weighting functions for each hearing group. 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:
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools</a>.
Table 4--Thresholds Identifying the Onset of Auditory Injury
----------------------------------------------------------------------------------------------------------------
AUD INJ onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 222 dB; Cell 2: LE,LF,24h: 197 dB.
LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans.......... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,HF,24h: 201 dB.
LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans.... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,VHF,24h: 181 dB.
LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 223 dB; Cell 8: LE,PW,24h: 195 dB.
LE,PW,24h: 183 dB.
[[Page 34477]]
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 230 dB Cell 10: LE,OW,24h: 199 dB.
LE,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, and weighted cumulative sound
exposure level (LE,p) has a reference value of 1 [micro]Pa\2\s. In this table, criteria are abbreviated to be
more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
hearing range of marine mammals underwater (i.e., 7 Hz to 165 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 and OW 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.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the proposed project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., pile driving and removal, and
DTH).
The project includes vibratory pile installation and removal,
impact pile driving, and DTH. Source levels for these activities are
based on reviews of measurements of the same or similar types and
dimensions of piles available in the literature. Source levels for each
pile size are presented in table 5. Source levels for vibratory
installation and removal of piles of the same diameter are assumed to
be the same.
Table 5--Estimates of Mean Underwater Sound Levels Generated During In-Water Vibratory and Impact Pile
Installation and Vibratory Pile Removal
----------------------------------------------------------------------------------------------------------------
Proxy sound source levels at
10m (dB re 1 [mu]Pa)
Method Pile size and type --------------------------------- Reference
Peak SEL RMS SPL
----------------------------------------------------------------------------------------------------------------
No Bubble Curtain in use (Unattenuated)
----------------------------------------------------------------------------------------------------------------
Vibratory removal................. H-pile............... ......... ......... 160 NMFS, 2023.
Vibratory removal................. 20-in steel pile pile ......... ......... 163 U.S. Navy, 2013.
Vibratory Installation and removal 36-in steel pile ......... ......... 166 NMFS, 2023.
(temporary).
Vibratory Installation............ 48-in steel pile..... ......... ......... 171 U.S. Navy, 2013.
Impact Installation............... 48-in steel pile..... 213 179 195 Caltrans, 2020.
DTH............................... 36-in steel pile 174 164 174 Denes et al., 2019;
(temporary). NMFS, 2022a; Reyff
and Heyvaert, 2019;
Reyff, 2020.
DTH............................... 48-in steel pile..... 178 168 178 NMFS, 2024.
----------------------------------------------------------------------------------------------------------------
Bubble Curtain in use (Attenuated) \1\
----------------------------------------------------------------------------------------------------------------
Vibratory Installation............ 48,60,72-in steel ......... ......... 166 U.S. Navy, 2013.
pile.
Impact Installation............... 48-in steel pile..... 208 174 190 Caltrans, 2020.
Impact Installation............... 60,72-in steel pile.. 205 180 190 Caltrans, 2020.
DTH............................... 48-in steel pile..... 173 163 173 NMFS, 2024.
DTH............................... 60,72-in steel pile.. 169 176 169 NOAA, 2023.
----------------------------------------------------------------------------------------------------------------
Note: peak = peak sound level; rms = root mean square; SEL = sound exposure level.
1 Attenuated source levels with 5dB reduction due to use of a bubble curtain during these activities (Caltrans,
2015; Austin et al., 2016).
TL is the decrease in acoustic intensity as an acoustic pressure
wave propagates out from a source. TL parameters vary with frequency,
temperature, sea conditions, current, source and receiver depth, water
depth, water chemistry, and bottom composition and topography. The
general formula for underwater TL is:
TL = B x Log10 (R<INF>1</INF>/R<INF>2</INF>),
Where:
TL = transmission loss in dB
B = transmission loss coefficient
R<INF>1</INF> = the distance of the modeled SPL from the driven
pile, and
R<INF>2</INF> = the distance from the driven pile of the initial
measurement
Absent site-specific acoustical monitoring with differing measured
TL, a practical spreading value of 15 is used as the TL coefficient in
the above formula. Site-specific TL data for Resurrection Bay are not
available; therefore, the default coefficient of 15 is used to
determine the distances to the Level A harassment and Level B
harassment thresholds.
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional User
Spreadsheet tool to accompany the 2024 Updated Technical Guidance that
can be used to relatively simply predict an isopleth distance for use
in conjunction with marine mammal density or occurrence to help predict
potential takes. We note that because of some of the assumptions
included in the methods underlying this optional tool, we anticipate
that the resulting isopleth estimates are typically going to be
overestimates of some degree, which may result in an overestimate of
potential take by Level A harassment. However, this optional tool
offers the best way to estimate isopleth distances
[[Page 34478]]
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 User
Spreadsheet (e.g., number of piles per day, duration and/or strikes per
pile) The resulting estimated isopleths, are presented in table 1. The
resulting estimated isopleths, are reported below (table 6).
Table 6--Level A and Level B Harassment Isopleths
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment zone (m) Level B
Method Pile size and type ----------------------------------------------------------------- harassment
LF HF VHF PW OW zone (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
No Bubble Curtain in use (Unattenuated)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory removal........................ H-pile...................... 17.7 6.8 14.4 22.7 7.6 4,641.6
Vibratory removal........................ 20-in steel pile pile....... 9.6 3.7 7.8 12.3 4.1 7,356.4
Vibratory Installation and removal....... 36-in steel pile (temporary) 19.9 7.6 16.2 25.6 8.6 11,659.1
Vibratory Installation................... 48-in steel pile............ 42.8 16.4 35 55.1 18.5 \1\ 25,118.9
Impact Installation...................... 48-in steel pile............ 2,822.4 360.1 4,367.6 2,507.3 934.6 1,359.4
DTH...................................... 36-in steel pile (temporary) 3,145.1 401.3 4867 2794 1,041.5 \1\ 39,811
DTH...................................... 48-in steel pile............ 6151 784.7 9518 5,463.9 2,036.7 \1\ 73,564
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bubble Curtain in use (Attenuated)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation................... 48-in steel pile............ 17 6.5 13.9 21.9 7.4 11,659.1
Vibratory Installation................... 60-in steel pile............ 19.9 7.6 16.2 25.6 8.6 11,659.1
Vibratory Installation................... 72-in steel pile............ 24.1 9.2 19.7 31 10.4 11,659.1
Impact Installation...................... 48-in steel pile............ 1,310 167 2,027.3 1,163.8 433.8 631.0
Impact Installation...................... 60,72-in steel pile......... 2,716 346.6 4,203.6 2,413.1 899.5 1,000
DTH...................................... 48-in steel pile............ 2,854.8 3,64.2 4,417.9 2,536.1 954.4 \1\ 34,145
DTH...................................... 60-in steel pile............ 14,816.7 1,890.4 22,928.9 13,162.6 4,906.5 18,478
DTH...................................... 72-in steel pile............ 19,415.4 2,477.2 30,045.4 1,7247.9 6,429.3 18,478
--------------------------------------------------------------------------------------------------------------------------------------------------------
1 These harassment zones extend past than the shoreline of Resurrection Bay, so land masses would block sound transmission and distances would be
truncated.
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.
TMC calculated occurrence estimates based on literature and
communication with locals in the Seward area. They then multiplied that
occurrence by the estimated days of work. After review of their
occurrence estimates, NMFS believed some of the estimates to be
inconsistent with the cited literature and local communications.
Following careful review of the analysis and literature presented by
TMC in its application, including marine mammal occurrence data and
estimates, NMFS has preliminarily determined that different occurrence
calculations for some species based on seasonality (peak vs off-peak),
represent the best available scientific information for marine mammal
abundance in the action area (table 7, see TMC application for more
details). This change from what TMC originally proposed was done in
consultation with the NMFS Alaska Region and other active Seward
actions (see 89 FR 10409, December 20, 2024; 90 FR 21754, May 21,
2025). The revised application reflects these changes.
As described above, the estimated number of days of in-water
construction is 203. There is also some potential for take by Level A
harassment for all species during impact pile driving and DTH
activities due to the large Level A harassment zones. In some
instances, the largest zones for each species are greater than the
shutdown zones either due to the cryptic nature and assumed lower
detectability of some species or due to the high sound levels produced.
TMC calculated take by Level A harassment by calculating the ratio of
average area of the Level A harassment zones for all activities divided
by the maximum area of the Level B harassment zone and multiplying this
ratio by the estimated total exposure estimate. Take by Level B
harassment was then calculated by subtracting the calculated take by
Level A harassment from the total exposure estimate.
Table 7--Species Occurrence Estimated
------------------------------------------------------------------------
Species Abundance estimate
------------------------------------------------------------------------
Gray whale............................. Three whales per month during
spring migration in outer
Resurrection Bay.
Fin whale.............................. Two whales every week in outer
Resurrection Bay.
Humpback whale......................... Peak: 1/day Off-peak: 1 every
other day.
Killer whale........................... Peak: 7/week Off-peak: 5/week.
Dall's porpoise........................ 10 every other day in outer
Resurrection Bay.
Harbor porpoise........................ 1/day.
Harbor seal............................ 12/day.
Steller sea lion....................... Peak: 8/day Off-peak: 2/day.
------------------------------------------------------------------------
[[Page 34479]]
Table 8--Proposed Take by Stock, Harassment Type, and as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
Proposed authorized take
-------------------------------- Proposed take
Species Stock Level A Level B as percentage
harassment harassment of stock
----------------------------------------------------------------------------------------------------------------
Gray whale........................... Eastern North Pacific... 1 2 <1
Fin whale............................ Northeast Pacific....... 2 6 \1\ <1
Humpback whale \2\................... Hawaii.................. 16 54 <1
Mexico.................. 3 6 \3\ <1
Western North Pacific... 0 1 <1
Killer whale \4\..................... AT1 Transient........... 0 7 \5\ NA
Gulf, Aleutian, Bering 2 37 6.6
Transient. 6 148 8.0
ENP Alaska Resident.....
Dall's porpoise...................... Alaska.................. 146 374 UND \6\
Harbor porpoise...................... Gulf of Alaska.......... 57 146 <1
Harbor seal.......................... Prince William Sound.... 517 1,919 5.4
Steller sea lion..................... Western United States... 111 904 2
----------------------------------------------------------------------------------------------------------------
\1\ Based on 2,554 animals discussed in SARs, although it's noted that this is likely an underestimate.
\2\ Based on proportion of each distinct population segment (DPS) being in resurrection bay: 89 percent Hawaii,
10 percent Mexico, and 1 percent Western North Pacific (NMFS, 2021).
\3\ Based on 918 animals discussed in SARs, derived from Wade, 2021.
\4\ Based on a proportion from acoustic monitoring of stocks in Resurrection Bay: 95.7 percent ENP residents,
2.7 percent Gulf/Aleutian/Bering transients, and 1.6 percent AT1 transients (Yurk et al., 2010).
\5\ NMFS considers any exposure of AT1 whales would likely be of a group, here assumed to consist of 7
individuals, due to the small stock size and low likelihood of individual encounters. See the Small Numbers
section of this notice for additional discussion.
\6\ 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.
TMC must ensure that construction supervisors and crews, the
monitoring team, and relevant TMC staff are trained prior to the start
of all pile driving and DTH activity, so that responsibilities,
communication procedures, monitoring protocols, and operational
procedures are clearly understood. New personnel joining during the
project must be trained prior to commencing work.
Pre- and Post-Activity Monitoring
<bullet> Monitoring must take place from 30 minutes prior to
initiation of pile driving and DTH activity (i.e., pre-clearance
monitoring) through 30 minutes post-completion of pile driving and DTH
activity; and,
<bullet> Pre-start clearance monitoring must be conducted during
periods of visibility sufficient for the lead protected species
observer (PSO) to determine that the shutdown zones indicated in table
10 are clear of marine mammals. Pile driving and DTH may commence
following 30 minutes of observation when the determination is made that
the shutdown zones are clear of marine mammals.
Soft Start
TMC must use soft start techniques when impact pile driving. Soft
start requires contractors to provide an initial set of three strikes
at reduced energy, followed by a 30-second waiting period, then two
subsequent reduced-energy strike sets. A soft start must be implemented
at the start of each day's impact pile driving and at any time
following cessation of impact pile driving for a period of 30 minutes
or longer.
Shutdown Zones
TMC would establish shutdown zones for all pile driving activities.
The purpose of a shutdown zone is generally to define an area within
which shutdown of the activity would occur upon sighting of a marine
mammal (or in anticipation of an animal entering the defined area).
If a marine mammal is observed entering or within the shutdown
zones indicated in table 9, pile driving and DTH must be delayed or
halted. For in-water heavy machinery activities other than pile
driving, if a marine mammal comes within 10-m, work must stop and
vessels must reduce speed to the minimum level required to maintain
steerage and safe working conditions. A 10-m shutdown zone would also
serve to protect marine mammals from physical interactions with project
vessels during pile driving and other construction activities, such as
barge positioning or drilling. If an activity is delayed or halted due
to the presence of a marine mammal, the activity may not
[[Page 34480]]
commence or resume until either the animal has voluntarily exited and
been visually confirmed beyond the shutdown zone indicated in table 9,
or 15 minutes have passed without re-detection of the animal.
Construction activities must be halted upon observation of a species
for which incidental take is not authorized or a species for which
incidental take has been authorized but the authorized number of takes
has been met entering or within the harassment zone.
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 the animal's presence within the
estimated harassment zone would be documented.
TMC would also establish shutdown zones for all marine mammals for
which take has not been authorized or for which incidental take has
been authorized but the authorized number of takes has been met. These
zones are equivalent to the Level B harassment zones for each activity.
If a marine mammal species for which take is not authorized by this IHA
enters the shutdown zone, all in-water activities would cease until the
animal leaves the zone or has not been observed for at least 15
minutes, and TMC would notify NMFS about the species and precautions
taken. Pile driving would proceed if the non-IHA species is observed to
leave the Level B harassment zone or if 15 minutes have passed since
the last observation.
If shutdown and/or clearance procedures would result in an imminent
safety concern, as determined by TMC or its designated officials, the
in-water activity would be allowed to continue until the safety concern
has been addressed, and the animal would be continuously monitored.
Table 9--Shutdown Zones and Level B Harassment Zones
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A shutdown zone (m) Level B
Method Pile size and type ------------------------------------------------------- monitoring
LF HF VHF PW OW zone (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
No Bubble Curtain in use
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory removal............................. H-pile........................... 20 10 15 25 10 4,645
Vibratory removal............................. 20-in steel pile pile............ 10 10 10 15 10 7,360
Vibratory Installation and removal............ 36-in steel pile (temporary)..... 20 10 20 30 10 11,660
Vibratory Installation........................ 48-in steel pile................. 45 20 35 60 20 *24,100
Impact Installation........................... 48-in steel pile................. 2,000 365 300 300 300 1,360
DTH........................................... 36-in steel pile (temporary)..... 2,000 405 300 300 300 *24,100
DTH........................................... 48-in steel pile................. 2,000 785 300 300 300 *24,100
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bubble Curtain in use
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation........................ 48-in steel pile................. 20 10 15 25 10 11,660
Vibratory Installation........................ 60-in steel pile................. 20 10 20 30 10 11,660
Vibratory Installation........................ 72-in steel pile................. 25 10 20 35 15 11,660
Impact Installation........................... 48-in steel pile................. 1,310 175 300 300 300 635
Impact Installation........................... 60,72-in steel pile.............. 2,000 350 300 300 300 1,000
DTH........................................... 48-in steel pile................. 2,000 365 300 300 300 *24,100
DTH........................................... 60-in steel pile................. 2,000 1,000 300 300 300 18,480
DTH........................................... 72-in steel pile................. 2,000 2,000 300 300 300 18,480
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Differs from table 6 Level B harassment zone because the harassment zone extends past the shoreline of Resurrection Bay, so land masses would block
sound transmission and distances would be truncated.
Protected Species Observers
The placement of PSOs during all construction activities (described
in the 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.
The TMC must employ PSOs and establish monitoring locations as
described in the marine mammal monitoring plan and the IHA. PSOs would
monitor the full shutdown zones and the Level B harassment zones to the
extent practicable. Monitoring zones provide utility for observing by
establishing monitoring protocols for areas adjacent to the shutdown
zones. Monitoring zones enable observers to be aware of and communicate
the presence of marine mammals in the project areas outside the
shutdown zones and thus prepare for a potential cessation of activity
should the animal enter the shutdown zone.
Bubble Curtain
A bubble curtain must be employed during installation of all 60-in
and 72-in piles and at least 12 of the 48-in piles (ones used in the
installation of the mooring dolphins). The bubble curtain must be
deployed in manner guaranteed to distribute air bubbles around 100
percent of the piling perimeter for the full depth of the water column.
The lowest bubble ring must be in contact with the mudline for the full
circumference of the ring. The weights attached to the bottom ring must
ensure 100 percent mudline contact. No parts of the ring or other
objects may prevent full mudline contact. Air flow to the bubblers must
be balanced around the circumference of the pile.
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 would result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
[[Page 34481]]
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
<bullet> Mitigation and monitoring effectiveness.
Visual Monitoring
Marine mammal monitoring must be conducted in accordance with the
conditions in this section and the IHA. Marine mammal monitoring during
pile driving and DTH activities must be conducted by PSOs meeting the
following requirements:
<bullet> PSOs must be independent of the activity contractor (for
example, employed by a subcontractor) and have no other assigned tasks
during monitoring periods;
<bullet> At least one PSO must have prior experience performing the
duties of a PSO during construction activity pursuant to a NMFS-issued
incidental take authorization;
<bullet> Other PSOs may substitute relevant experience, education
(degree in biological science or related field), or training for prior
experience performing the duties of a PSO during construction activity
pursuant to a NMFS-issued incidental take authorization; and,
<bullet> Where a team of three or more PSOs is required, a lead
observer or monitoring coordinator would be designated. The lead
observer would be required to have prior experience performing the
duties of a PSO during construction activities pursuant to a NMFS-
issued incidental take authorization.
<bullet> PSOs must be approved by NMFS prior to beginning any
activities subject to this IHA.
PSOs must have the following additional qualifications:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including the identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates, times and reason for implementation
of mitigation (or why mitigation was not implemented when required);
and marine mammal behavior; and,
<bullet> Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
TMC must assign a minimum of three PSOs to monitor during pile
driving and DTH. One PSO must be stationed at the pile driving site,
and the other PSOs must be stationed at the best practicable location
for monitoring the Level A and Level B harassment zones (see Marine
Mammal Monitoring Plan). All PSOs would have access to high-quality
binoculars, range finders to monitor distances, and a compass to record
bearing to animals as well as radios or cells phones for maintaining
contact with work crews.
Monitoring would be conducted 30 minutes before, during, and 30
minutes after all in water construction activities. In addition, PSOs
would record all incidents of marine mammal occurrence, regardless of
distance from activity, and would document any behavioral reactions in
concert with distance from piles being driven or removed. Pile driving
activities include the time to install or remove a single pile or
series of piles, as long as the time elapsed between uses of the pile
driving equipment is no more than 30 minutes.
TMC shall conduct briefings between construction supervisors and
crews, PSOs, TMC staff prior to the start of all pile driving
activities and when new personnel join the work. These briefings must
explain responsibilities, communication procedures, marine mammal
monitoring protocol, and operational procedures.
Reporting
A draft marine mammal monitoring report would be submitted to NMFS
within 90 days after the completion of pile driving and removal
activities, or 60 days prior to a requested date of issuance from any
future IHAs for projects at the same location, whichever comes first.
The report would include an overall description of work completed, a
narrative regarding marine mammal sightings, and associated electronic
PSO data sheets. Specifically, the report must include:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> 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) and the total equipment
duration for vibratory removal for each pile or total number of strikes
for each pile (impact driving);
<bullet> PSO locations during marine mammal monitoring;
<bullet> Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance;
<bullet> Upon observation of a marine mammal, the following
information: (1) Name of PSO who sighted the animal(s) and PSO location
and activity at the time of sighting; (2) Time of sighting; (3)
Identification of the animal(s) (e.g., genus/species, lowest possible
taxonomic level, or unidentifiable), 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 sightings (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, sex class, etc.); (7) Animal's
closest point of approach and estimated time spent within the
harassment zone; (8) Description of any marine mammal behavioral
observations (e.g., observed behaviors such as feeding or traveling),
including an assessment of behavioral responses thought to have
resulted from the activity (e.g., no response or changes
[[Page 34482]]
in behavioral state such as ceasing feeding, changing direction,
flushing, or breaching);
<bullet> Number of marine mammals detected within the harassment
zones and shutdown zones; by species; and,
<bullet> Detailed information about any implementation of any
mitigation triggered (e.g., shutdowns and delays), a description of
specific actions that ensured, and resulting changes in behavior of the
animal(s), if any.
If no comments are received from NMFS within 30 days, the draft
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, the TMC must immediately
cease the specified activities and report the incident to the Office of
Protected Resources (<a href="/cdn-cgi/l/email-protection#4414166a0d10146a092b2a2d302b362d2a231621342b363037042a2b25256a232b32"><span class="__cf_email__" data-cfemail="3363611d7a67631d7e5c5d5a475c415a5d546156435c414740735d5c52521d545c45">[email protected]</span></a>), NMFS and to
the Alaska Regional Stranding Coordinator as soon as feasible. If the
death or injury was clearly caused by the specified activity, TMC 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 TMC must not resume their activities until notified by
NMFS. The report must include the following information:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and,
<bullet> General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the discussion of our analysis applies to all
species listed in table 2, given that the anticipated effects of this
activity on these different marine mammal stocks are expected to be
similar. There is little information about the nature or severity of
the impacts, or the size, status, or structure of any of these species
or stocks that would lead to a different analysis for this activity.
Pile driving and DTH activities associated with the TMC
construction project has the potential to disturb or displace marine
mammals. Specifically, the project activities may result in take, in
the form of Level A and Level B harassment, from underwater and in-air
sounds generated from pile driving and removal. 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 serious injury or mortality is expected,
even in the absence of required mitigation measures, given the nature
of the activities. The potential for harassment would be further
minimized through the construction method and the implementation of the
planned mitigation measures (see Mitigation section).
Take by Level A harassment is authorized for all species to account
for the possibility that an animal could enter a Level A harassment
zone prior to detection, and remain within that zone for a duration
long enough to incur auditory injury before being observed and TMC
shutting down pile driving activity. Given the short duration drive
each pile and breaks between pile installations (to reset equipment and
move piles into place), an animal would have to remain within the area
estimated to be ensonified above the Level A harassment threshold for
multiple hours. This is highly unlikely given marine mammal movement in
the area. The number of takes by Level A harassment authorized is low
for all marine mammal species. Any take by Level A harassment is
expected to arise from, at most, a small degree of auditory injury,
i.e., minor degradation (likely only a few dB) of hearing capabilities
within regions of hearing that align most completely with the energy
produced by vibratory and impact pile driving (i.e., the low-frequency
region below 2 kHz), not severe hearing impairment or impairment within
the ranges of greatest hearing sensitivity. Animals would need to be
exposed to higher levels and/or longer duration than are expected to
occur here in order to incur any more than a small degree of auditory
injury. Due to the small degree anticipated, any auditory injury
incurred would not be expected to affect the reproductive success or
survival of any individuals, much less result in adverse impacts on the
species or stock.
Additionally, some subset of the individuals that are behaviorally
harassed could also simultaneously incur some small degree of TTS for a
short duration of time. However, since the hearing sensitivity of
individuals that incur TTS is expected to recover completely within
minutes to hours, it is unlikely that the brief hearing impairment
would affect the individual's long-term ability to forage and
communicate with conspecifics, and would therefore not likely impact
reproduction or survival of any individual marine mammal, let alone
adversely affect rates of recruitment or survival of the species or
stock.
Behavioral responses of marine mammals to pile driving and DTH in
Seward are expected to be mild, short term, and temporary. Marine
mammals within the Level B harassment zones may not show any visual
cues they are disturbed by activities or they 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 that pile
[[Page 34483]]
driving and DTH would occur for only a portion of the project's
duration, any harassment would be temporary. Additionally, many of the
species present in region would only be present temporarily based on
seasonal patterns or during transit between other habitats. These
temporarily present species would be exposed to even smaller periods of
noise-generating activity, further decreasing the impacts.
Any impacts on marine mammal prey that would occur during TMC's
planned 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.
For all species and stocks, take would occur within a limited,
confined area (adjacent to the project site) of the stock's range, and,
there are no known BIAs near the project area that would be impacted by
TMC's activities. While harbor seal is the species most likely to occur
within the immediate project area, the nearest officially documented
haulout is outside of the ensonified areas. There is a possible haulout
site for harbor seals near project area on the sediment groin, although
the only documentation of this sighting is from 1999. There are no
regular haulouts in the immediate project vicinity; the next closest
regular haulout is 14 km away. There are no Steller sea lion haulouts
in the project area. The closest haulout is 21 km from the project
area.
In addition, it is unlikely that minor noise effects in a small,
localized area of habitat would have any effect on the reproduction or
survival of any individuals, much less the stocks' annual rates of
recruitment or survival. Specific to the AT1 stock of killer whales,
which is depleted and numbers only seven individuals, no recruitment
has occurred in this stock since 1984, and it is unlikely to recover
(Young et al., 2025). In combination, we believe that these factors, as
well as the available body of evidence from other similar activities,
demonstrate that the potential effects of the specified activities
would have only minor, short-term effects on individuals. The specified
activities are not expected to impact rates of recruitment or survival
and would therefore not result in population-level impacts.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect any of the species
or stocks through effects on annual rates of recruitment or survival:
<bullet> No serious injury or mortality is anticipated or
authorized;
<bullet> Take by Level A harassment is authorized for all species
due to the large Level A harassment zones but would be small amounts
and of a low degree;
<bullet> For all species and stocks, Seward is a very small and
peripheral part of their range;
<bullet> The intensity of anticipated takes by Level B harassment
is relatively low for all stocks. Level B harassment would be primarily
in the form of behavioral disturbance, resulting in avoidance of the
project areas around where impact or vibratory pile driving is
occurring, with some low-level TTS that may limit the detection of
acoustic cues for relatively brief amounts of time in relatively
confined footprints of the activities;
<bullet> Effects on species that serve as prey for marine mammals
from the activities are expected to be short-term and, therefore, any
associated impacts on marine mammal feeding are not expected to result
in significant or long-term consequences for individuals, or to accrue
to adverse impacts on their populations;
<bullet> The project area does not overlap any BIAs or any other
important areas for marine mammals;
<bullet> The ensonified areas are small relative to the overall
habitat ranges of all species and stocks; and,
<bullet> The lack of anticipated significant or long-term negative
effects to marine mammal habitat.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the monitoring and mitigation
measures, NMFS finds that the total marine mammal take from the planned
activities would have a negligible impact on all affected marine mammal
species or stocks.
Small Numbers
As noted previously, only take of small numbers of marine mammals
may be authorized under section 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 (86 FR 5322,
January 19, 2021). Additionally, other qualitative factors may be
considered in the analysis, such as the temporal or spatial scale of
the activities.
Another circumstance in which NMFS considers it appropriate to make
a small numbers finding is in the case of a species or stock that may
potentially be taken but is either rarely encountered or only expected
to be taken on rare occasions. In that circumstance, one or two assumed
encounters with a group of animals (meaning a group that is traveling
together or aggregated, and thus exposed to a stressor at the same
approximate time) should reasonably be considered small numbers,
regardless of consideration of the proportion of the stock (if known),
as rare encounters resulting in take of one or two groups should be
considered small relative to the range and distribution of any stock.
The AT1 stock of killer whales is exceptionally small, estimated to
include only seven individuals. While it is possible that AT1 whales
could visit Seward, passive acoustic monitoring in Resurrection Bay
showed that the vast majority of killer whales detected were from the
Alaska Resident stock, with AT1 whales detected only 1.6 percent of the
time (Myers et al., 2021). NMFS considers it reasonably likely that the
AT1 stock may occur one time during the course of the project at this
project site. Based on the rarity of encounters with this group
expected at the project site, this represents small numbers for this
stock.
For all other stocks, except for 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
[[Page 34484]]
ago (Young et al., 2023). However, given the size of the most recent
estimate, the 520 takes of this stock proposed for authorization
clearly represents small numbers of this stock.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals would be taken relative to the population
size of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
In order to issue an IHA, NMFS must find that the specified
activity would not have an ``unmitigable adverse impact'' on the
subsistence uses of the affected marine mammal species or stocks by
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50
CFR 216.103 as an impact resulting from the specified activity: (1)
That is likely to reduce the availability of the species to a level
insufficient for a harvest to meet subsistence needs by: (i) Causing
the marine mammals to abandon or avoid hunting areas; (ii) Directly
displacing subsistence users; or (iii) Placing physical barriers
between the marine mammals and the subsistence hunters; and (2) That
cannot be sufficiently mitigated by other measures to increase the
availability of marine mammals to allow subsistence needs to be met.
There are two species of marine mammals that traditionally have
been taken as part of subsistence harvests in Resurrection Bay: Steller
sea lion and harbor seal. The most recent data on subsistence-harvested
marine mammals near Seward is of harbor seals in 2002, and there is no
current local marine mammal subsistence harvest in Seward.
The proposed project is not likely to adversely impact the
availability of any marine mammal species or stocks that are commonly
used for subsistence purposes or impact subsistence harvest of marine
mammals in the region. Although the proposed activities are located in
a region where subsistence harvests have occurred historically, there
is currently no marine mammal subsistence harvest. The project location
is adjacent to heavily traveled industrialized waterways and all
project activities would take place within waterfronts where
subsistence activities do not generally occur. Some minor, short-term
harassment of Steller sea lions and harbor seals could occur, but any
effects on subsistence harvest activities in the project areas would be
minimal, and not have an adverse impact.
Based on the description of the specified activity, the measures
described to minimize adverse effects on the availability of marine
mammals for subsistence purposes, and the proposed mitigation and
monitoring measures, NMFS has preliminarily determined that there would
not be an unmitigable adverse impact on subsistence uses from TMC'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 fin whales (Northeast
Pacific Stock), humpback whales (Mexico and western North Pacific 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 TMC for conducting the Seward Cruise Ship Passenger
Dock and Terminal Facility Project in Seward Alaska, provided the
previously mentioned mitigation, monitoring, and reporting requirements
are incorporated. A draft of the proposed IHA can be found at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA for the proposed
construction project. We also request comment on the potential renewal
of this proposed IHA as described in the paragraph below. Please
include with your comments any supporting data or literature citations
to help inform decisions on the request for this IHA or a subsequent
renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, 1-year renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activity section of this notice is planned, or (2) the activities as
described in the Description of Proposed Activity section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
<bullet> A request for renewal is received no later than 60 days
prior to the needed renewal IHA effective date (recognizing that the
renewal IHA expiration date cannot extend beyond 1 year from expiration
of the initial IHA).
<bullet> The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
(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.
<bullet> Upon review of the request for renewal, the status of the
affected species or stocks, and any other pertinent information, NMFS
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: July 17, 2025.
Shannon Bettridge,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2025-13708 Filed 7-21-25; 8:45 am]
BILLING CODE 3510-22-P
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