Notice2026-08299
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Kensington Dock Repair Project in Berners Bay, Alaska
Primary source
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Published
April 29, 2026
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from Coeur Alaska, Inc. (Coeur) for authorization to take marine mammals incidental to the Kensington Dock Repair Project in Berners Bay, Alaska (AK). 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 91 Issue 82 (Wednesday, April 29, 2026)</title>
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[Federal Register Volume 91, Number 82 (Wednesday, April 29, 2026)]
[Notices]
[Pages 23065-23088]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-08299]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XF566]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Kensington Dock Repair Project
in Berners Bay, 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 Coeur Alaska, Inc. (Coeur)
for authorization to take marine mammals incidental to the Kensington
Dock Repair Project in Berners Bay, Alaska (AK). 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 May 29,
2026.
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#b9f0ede997fecbd8d1d8d4f9d7d6d8d897ded6cf"><span class="__cf_email__" data-cfemail="713825215f36031019101c311f1e10105f161e07">[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/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</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: Krista Graham, 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.) directs 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). If such findings are made, NMFS must prescribe the
permissible methods of taking; 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 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
(see also 16 U.S.C. 1362; 50 CFR 216.3, 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 December 9, 2026, NMFS received a request from Coeur for an IHA
to take marine mammals incidental to the replacement of two mooring
dolphins at the Kensington Dock in Berners Bay, AK. Following NMFS'
review of the application, Coeur submitted a revised application on
February 20, 2026. Following additional questions, Coeur submitted a
final revised application on March 12, 2026. The application was deemed
adequate and complete on March 17, 2026. Coeur's request is for the
take of 7 species of marine mammals (13 stocks) by Level B harassment
only. Neither Coeur nor NMFS expects serious injury or mortality to
result from this activity; therefore, an IHA is appropriate.
[[Page 23066]]
Description of Proposed Activity
Overview
Coeur is proposing construction activities that include pile
driving (vibratory, impact, and down-the-hole (DTH)) and removal
(vibratory). Underwater sound from these activities may result in
behavioral harassment of marine mammals.
The purpose of Coeur's project is to replace two damaged mooring
dolphins (D-2 and D-4) at the Kensington Dock facility. These docks
sustained structural damage from two separate vessel impacts. The
project would restore the structural integrity of the mooring system
and ensure the dock can continue to safely berth vessels. The
Kensington Dock facility provides the only marine access in Berners Bay
for importing supplies and fuel and exporting mined ore concentrate
from the remote mine site.
Dates and Duration
The proposed IHA would be valid for the statutory maximum of 1 year
from the date of effectiveness. It would 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.
Pile driving is expected to occur sometime after the project is
proposed to begin on July 1, 2026. Thirty-three days of in-water pile
driving are estimated for this project, spanning 8 to 10 weeks. This
includes 30 days of anticipated pile driving and a 10 percent (3-day)
contingency. However, project delays may occur due to several factors,
including project funding, permitting requirements, equipment and/or
material availability, weather-related delays, equipment maintenance
and/or repair, and other contingencies. Pile driving would occur only
during daylight hours (i.e., approximately 12-16 hours/day).
Specific Geographic Region
The Kensington Dock facility is in Slate Cove along the southern
shoreline of Berners Bay, AK. Berners Bay is a large, deep inlet
located approximately 40 miles northwest of Juneau, AK, and 35 miles
southeast of Haines, AK. Berners Bay is 3.5 miles wide at the entrance,
adjacent to Lynn Canal, and surrounded by the Tongass National Forest
(see figure 1 of this notice and figure 1-2 of the application).
BILLING CODE 3510-22-P
[[Page 23067]]
[GRAPHIC] [TIFF OMITTED] TN29AP26.000
BILLING CODE 3510-22-C
Detailed Description of the Specified Activity
The Kensington Dock facility configuration consists of four mooring
dolphins (D-1, D-2, D-3, and D-4), spaced approximately 50 linear feet
(ft) on center, centered on a 140-ft-long floating self-supported steel
transfer bridge. Each dolphin consists of a single vertical steel pipe
pile with a pre-stressed rock anchor installed at its center. The rock
anchor is drilled into the existing bedrock surface below the end of
the pipe pile. Two batter piles are used to resist lateral forces.
Piles are connected at the top with a welded knife plate. The vertical
piles are fitted with used loader tires that provide limited energy
absorption during vessel berthing operations.
Mooring dolphins D-2 and D-4, which have both sustained structural
damage, would be replaced from an anchored barge, using vibratory and
impact hammers to install and remove piles. Temporary template piles
(24-inch steel pipe piles or equivalent) would be installed via
vibratory hammer to support permanent pile template framing for each
dolphin installation. Dolphin D-2 would consist of one 30-inch steel
pipe vertical pile and two 24-inch steel pipe batter piles; dolphin D-4
would consist of one 48-inch steel pipe vertical pile and two 24-inch
steel pipe batter piles. Dolphin D-4 is larger because it is the first
pile the
[[Page 23068]]
vessel contacts, and it must support the entire vessel until it makes
contact with the other three mooring dolphins and lines up with the
dock. The vertical and batter piles would be driven to bedrock, first
with a vibratory hammer and then with an impact hammer to seat into
bedrock and verify pile end bearing. The replacement dolphins would be
slightly offset from their original locations to allow continued dock
operations throughout the repair project and to avoid conflicts with
the existing vertical pile rock anchors. Rock anchors would then be
installed in all six dolphin piles: two vertical piles and four batter
piles. Rock anchors would be installed using DTH methods. With DTH, a
shaft would be drilled beyond the pile tip and into the underlying
bedrock. A high-strength steel anchor rod coated for corrosion
protection would be placed in the casing and inserted into the bottom
of the drilled shaft. The drilled shaft would be filled with concrete
to properly anchor the vertical and batter piles to the bedrock under
pre-stress.
Once the new dolphins are installed and operational, the existing
damaged dolphins would be removed by severing the piles and rock
anchors at the mudline. NMFS does not anticipate that removing the
existing damaged dolphins will result in take of marine mammals, and
this activity is not discussed further. All temporary piles would be
removed using a vibratory hammer. No simultaneous pile driving would
occur. Pile quantities and construction methods are summarized in table
1.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Table 1--Pile Types, Construction Method, Quantities, and Days of Effort
----------------------------------------------------------------------------------------------------------------
Total estimated
Maximum number of days Total
Source Construction action number of pile driving will number of
piles/day occur \1\ piles
----------------------------------------------------------------------------------------------------------------
Vibratory
----------------------------------------------------------------------------------------------------------------
Template piles (24'' steel pipe or Installation............. 5 2 10
equivalent).
Template piles (24'' steel pipe or Removal.................. 5 2 10
equivalent).
Batter piles (24'' steel pipe or Installation............. 1 4 4
equivalent).
Batter piles (24'' steel pipe or Removal.................. 2 2 4
equivalent).
Vertical piles (30'' steel pipe)....... Installation............. 1 1 1
Vertical piles (30'' steel pipe)....... Removal.................. 1 2 2
Vertical piles (48'' steel pipe)....... Installation............. 1 1 1
----------------------------------------------------------------------------------------------------------------
Impact
----------------------------------------------------------------------------------------------------------------
Batter piles (24'' steel pipe or Installation............. 2 2 4
equivalent).
Vertical piles (30'' steel pipe)....... Installation............. 1 1 1
Vertical piles (48'' steel pipe)....... Installation............. 1 1 1
----------------------------------------------------------------------------------------------------------------
DTH
----------------------------------------------------------------------------------------------------------------
Rock Anchors (6'' drill hole).......... Installation............. 1 6 6
----------------------------------------------------------------------------------------------------------------
\1\ The total estimated number of days of pile driving in this table (24) is less than the anticipated 33 days
of pile driving in the IHA application (i.e., 30 days of anticipated pile driving plus a 10 percent
contingency or buffer) to account for the possibility of construction overages. Total days of effort assume no
simultaneous pile-driving installation occurs.
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 seven potentially affected marine
mammal species or stocks. NMFS fully considered all 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 the species for which take is likely 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), as well as the potential biological
removal (PBR), where known. The MMPA defines PBR 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, the PBR and annual mortality and serious injury (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 area may extend beyond
U.S. waters. All managed stocks in this region are assessed in NMFS'
U.S. final 2024 SARs. All values presented in table 2 are the most
recent available at the time of publication
[[Page 23069]]
(including from the final 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, Stocks, and the Status of Marine Mammals With Estimated Take From the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/MMPA status; Stock abundance (CV;
Common name \a\ Scientific name Stock Strategic (Y/N) Nmin; most recent PBR Annual M/
\b\ abundance survey) \c\ SI \d\
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Order Artiodactyla--Infraorder Cetacea--Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae (rorquals):
Humpback whale \e\.............. Megaptera novaeangliae. Hawai[revaps]i......... -,-,N 11,278 (0.56, 7,265, 127 27.09
2020).
Mexico-North Pacific... T, D, Y N/A (N/A, N/A, 2006) UND 0.57
\f\.
Western North Pacific E, D, Y 1,084 (0.088, 1,007, 3.4 5.82
(WNP). 2006) \g\.
Minke whale..................... Balaenoptera Alaska................. -,-,N N/A (N/A, N/A, N/A) UND 0
acutorostrata. \h\.
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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) \i\.
Eastern Northern -,-,N 302 (N/A, 302, 2018) 2.2 0.2
Pacific Northern \j\.
Resident.
Eastern North Pacific -,-,N 587 (N/A, 587, 2012) 5.9 0.8
Gulf of Alaska, \k\.
Aleutian Islands, and
Bering Sea Transient.
West Coast Transient... -,-,N 349 (N/A, 349, 2018) 3.5 0.4
\l\.
Family Phocoenidae (porpoises):
Dall's porpoise................. Phocoenoides dalli..... Alaska................. -,-,N UND (UND, UND, 2015) UND 37
\m\.
Harbor porpoise................. Phocoena phocoena...... Northern Southeast -,-,N 1,619 (0.26, 1,250, 13 5.6
Alaska Inland Waters. 2019).
--------------------------------------------------------------------------------------------------------------------------------------------------------
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) \n\.
Eastern................ -,-,N 36,308 (N/A, 36,308, 2,178 92.3
2022) \o\.
Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... Lynn Canal/Stephens -,-,N 13,388 (N/A, 11,867, 214 50
Passage. 2016).
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\a\ 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>).
\b\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T); MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or 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.
\c\ 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 the coefficient of variation; N min is the minimum estimate of stock abundance. In some cases, a CV is not
applicable. N/A indicates data are unknown. UND (undetermined) PBR indicates data are available to calculate a PBR level, but a determination has been
made that calculating a PBR level using those data is inappropriate (see the SAR for details).
\d\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, vessel strikes). Annual M/SI is often not precisely determined and is sometimes reported as a minimum value or a range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
\e\ New SAR in 2022 following North Pacific humpback whale stock structure changes.
\f\ Abundance estimates are based upon data collected more than 8 years ago and, therefore, current estimates are considered unknown.
\g\ PBR in U.S. waters = 0.2, M/SI in U.S. waters = 0.06.
\h\ Reliable population estimates are not available for this stock. Please see Friday et al. (2013) and Zerbini et al. (2006) for additional information
on the number of minke whales in Alaska.
\i\ Nest, or the best estimate of abundance, is based upon counts of individuals identified from photo-ID catalogs.
\j\ Nest is based upon counts of individuals identified from photo-ID catalogs.
\k\ Nest is based upon counts of individuals identified from photo-ID catalogs.
\l\ Nest is based upon counts of individuals identified from photo-ID catalogs in analysis of a subset of data from 1958-2018.
\m\ 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.
\n\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the U.S.
only. The overall Nmin is 73,211 and overall PBR is 439.
\o\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the U.S.
only.
As indicated above, table 2 lists all 7 species (with 13 managed
stocks) that temporally and spatially co-occur with the specified
activity to the degree that incidental take is likely to occur.
While the general ranges for Pacific white-sided dolphins
(Lagenorhynchus obliquidens), fin whales (Balaenoptera physalus), and
gray whales (Eschrichtius robustus) include Southeast Alaska, there are
no documented sightings of these three species in the area. This
includes the marine mammal monitoring reports from Berners Bay (Blejwas
and Mathews, 2005; Coeur Alaska, Inc., 2011, 2012, 2013, 2014, 2015,
2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, and 2025), and
Southeast Alaska (Dahlheim et al., 2009). Therefore, the temporal and/
or spatial
[[Page 23070]]
occurrence of these three species is such that take is not expected to
occur, Coeur did not request, and NMFS is not proposing to authorize
the incidental take of these three species, and they are not discussed
further beyond the explanation provided here.
The project area does not overlap the designated critical habitat
for the Western DPS of Steller sea lions or the Mexico DPS of humpback
whales.
Much of Southeast Alaska's waters are considered Biologically
Important Areas (BIAs) for feeding humpback whales, including Berners
Bay (Wild et al., 2023). The Berners Bay humpback whale BIA covers a
240-square-kilometer (km\2\) (93-square-mile (mi\2\)) area. However,
this feeding BIA is effective during April and May. Since the project
is anticipated to begin after July 1, 2026, and span 8 to 10 weeks, it
falls outside the Berners Bay BIA's timeframe.
Harbor seals are commonly sighted in the waters of the inside
passages throughout Southeast Alaska. They occur year-round and are
regularly sighted in Berners Bay. It is anticipated that their
abundance in Berners Bay peaks with the spring spawning runs of
eulachon (Thaleichthys pacificus) and Pacific herring (Clupea
pallasii). Although harbor seals regularly haul out at three locations
in Berners Bay, these locations are outside of the project area. These
locations range in distance to the Kensington Dock from approximately
740 meters (m) (2,428 feet (ft)) at the Slate Cove haul out; to 2,880 m
(9,449 ft) at the Berner/Lace rivers (i.e., three to four sandbars at
the confluence of the Antler, Berner, and Lace rivers); to 5,000 m
(16,404 ft) at Point St. Mary's. During a July 12th aerial survey,
harbor seals were observed out of the water only on the three to four
river sandbars (outside of the project area) (Blejwas and Mathews,
2005).
Steller sea lion distribution in the project area is likely
seasonal and based on prey availability. Womble and Sigler (2006)
reported that they were found in Lynn Canal primarily from November to
March and in Berners Bay only during April and May, which is outside of
the Project's 8 to 10-week timeframe beginning July 1, 2026. The
nearest major haulouts are in Berners Bay (2.9 km (1.8 mi) away from
the construction site and well outside of the project area) and on
Benjamin Island (approximately 26 km (16 mi) southeast of the project
area), with the lowest abundance between May and Sept (Womble et al.,
2009). The nearest Steller sea lion rookery is 115 km (72 mi) west of
the project area.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of sound
exposure, it is necessary to understand the frequency ranges that
marine mammals can hear. Not all marine mammal species have equal
hearing capabilities or hear over the same frequency range (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 hearing ranges (behavioral or auditory-evoked potential
techniques) or on estimated hearing ranges (behavioral response data,
anatomical modeling, etc.). Generalized hearing ranges were chosen
based on the approximately 65 decibel (dB) threshold from composite
audiograms, previous analyses in NMFS (2018), and/or data from Southall
et al. (2007) and Southall et al. (2019). We note that the names of two
hearing groups and the generalized hearing ranges of all marine mammal
hearing groups have been recently updated (NMFS, 2024), as reflected in
table 3.
Table 3--Marine Mammal Hearing Groups
[NMFS, 2024]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans 7 Hz to 36 kHz.
(baleen whales).
High-frequency (HF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales,
beaked whales, bottlenose
whales).
Very High-frequency (VHF) 200 Hz to 165 kHz.
cetaceans (true porpoises,
Kogia, river dolphins,
Cephalorhynchid,
Lagenorhynchus cruciger & L.
australis).
Phocid pinnipeds (PW) 40 Hz to 90 kHz.
(underwater) (true seals).
Otariid pinnipeds (OW) 60 Hz to 68 kHz.
(underwater) (sea lions and
fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges may not be as broad. Generalized hearing range
chosen based on approximately 65 dB threshold from composite
audiogram, previous analysis in NMFS (2018), and/or data from Southall
et al. (2007) and Southall et al. (2019). Additionally, animals can
detect very loud sounds above and below the ``generalized'' hearing
range.
For more details 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 discusses how components of the specified activities
may affect 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
the specified activities. The Negligible Impact Analysis and
Determination section considers the content of this section, as well as
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 project
activities are likely to result from vibratory pile installation and
removal, impact pile driving, and DTH. The effects of underwater noise
from Coeur's proposed activities have the potential to result in Level
B harassment of marine mammals in the proposed project area.
NMFS has summarized a brief technical description of the physics of
sound and relevant measurement metrics (i.e., root-mean-squared (RMS),
Peak, and sound exposure level (SEL)) (NMFS, 2024), available online at
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>. We refer readers to this
document for definitions of the measurement terms and metrics used
herein.
[[Page 23071]]
There are a variety of types and degrees of effects on marine
mammals, prey species, and habitats that could result from the
specified activities. Below, we provide a brief description of the
types of sound generated by the specified activities, the general
impacts on marine mammals and their habitat from these activities, and
a related project-specific analysis that considers the proposed
mitigation measures.
Description of Sound Sources for the Specified Activities
Activities associated with the project that have the potential to
incidentally take marine mammals through exposure to sound include
impact hammers, vibratory hammers, and DTH drilling. Impact hammers
typically operate by repeatedly dropping and/or pushing a heavy piston
onto a pile to drive the pile into the substrate. Sound generated by
impact hammers is impulsive, characterized by rapid rise times and high
peak levels, a potentially injurious combination (Hastings and Popper,
2005). Vibratory hammers install piles by vibrating them and allowing
the hammer's weight to drive them into the substrate. Vibratory hammers
typically produce less sound (i.e., lower levels) 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; California
Department of Transportation (CALTRANS), 2015; 2020). Sounds produced
by vibratory hammers are non-impulsive; compared to sounds produced by
impact hammers, they have a slower rise time, reducing the probability
and severity of injury, and the sound energy is distributed over a
greater amount of time (Nedwell and Edwards, 2002; Carlson et al.,
2005).
DTH systems use a combination of drilling and percussive mechanisms
to advance a hole into the rock, with or without simultaneously
advancing a pile/casing into that hole. A DTH system is essentially a
drill bit that drills through the bedrock using a rotating function
like a normal drill, integrated with a hammering mechanism to increase
the speed of progress through the substrate (i.e., it is similar to a
``hammer drill'' hand tool). The sound produced by the DTH methods
simultaneously contains both a continuous non-impulsive component from
the drilling action and an impulsive component from the hammering
effect. Therefore, for purposes of evaluating Level A harassment and
Level B harassment under the MMPA, NMFS treats DTH systems as both
impulsive (Level A harassment thresholds) and continuous, non-impulsive
(Level B harassment thresholds) sound sources.
The likely or possible impacts of the Coeur's proposed activities
on marine mammals could involve both non-acoustic and acoustic
stressors. Potential non-acoustic stressors could result from the
physical presence of the equipment and personnel; however, given that
there are no known pinniped haul-out sites within the project area,
visual and other non-acoustic stressors would be limited, and any
impacts to marine mammals are expected to primarily be acoustic in
nature.
Potential Effects of Underwater Sound on Marine Mammals
The introduction of anthropogenic noise into the aquatic
environment from vibratory pile removal and vibratory and impact pile
installation is the primary means by which marine mammals may be
harassed from Coeur's specified activities. Anthropogenic sounds span a
broad range of frequencies and sound levels and can have highly
variable impacts on marine life, ranging from none or minor to
potentially severe responses, depending on received levels, duration of
exposure, behavioral context, and other factors. Broadly, underwater
sound from active acoustic sources, such as those in this project, can
potentially result in one or more of the following: temporary or
permanent hearing impairment, non-auditory physical or physiological
effects, behavioral disturbance, stress, and masking (Richardson et
al., 1995; Gordon et al., 2003; Nowacek et al., 2007; Southall et al.,
2007; G[ouml]tz et al., 2009).
We describe the more severe effects of certain non-auditory
physical or physiological effects only briefly, as we do not expect
that the use of vibratory, impact, or DTH hammers is reasonably likely
to result in such effects (see below for further discussion). For non-
auditory physical effects, while harbor seals and Steller sea lions are
known to haul out, there are no haul-outs or rookeries for either
species within the project area (see Description of Marine Mammals in
the Area of Specified Activities section). Ultimately, we expect that
any visual and/or other non-acoustic stressors would be limited and
that any impact on marine mammals would be acoustic in nature.
Potential physiological effects from sound sources, particularly
impulsive sound, can range from behavioral disturbance or tactile
perception to physical discomfort, slight injury to the internal organs
and the auditory system, or mortality (Yelverton et al., 1973). Non-
auditory physiological effects or injuries that theoretically might
occur in marine mammals exposed to high level underwater sound or as a
secondary effect of extreme behavioral reactions (e.g., change in dive
profile as a result of an avoidance reaction) caused by exposure to
sound include neurological effects, bubble formation, resonance
effects, and other types of organ or tissue damage (Cox et al., 2006;
Southall et al., 2007; Zimmer and Tyack, 2007; Tal et al., 2015).
However, the project activities considered here do not involve the use
of devices such as explosives or mid-frequency tactical sonar that are
associated with these types of effects.
In general, animals exposed to natural or anthropogenic sounds may
experience physical and psychological effects, ranging in magnitude
from none to severe (Southall et al., 2007, 2019). Exposure to
anthropogenic noise can result in auditory threshold shifts and
behavioral responses (e.g., avoidance, temporary cessation of foraging
and vocalizing, changes in dive behavior). It can also lead to non-
observable physiological responses, such as increased stress hormone
levels. Additional noise in a marine mammal's habitat can mask acoustic
cues used in daily functions, such as communication and predator-prey
detection.
The degree of effect of an acoustic exposure on marine mammals is
dependent on several factors, including, but not limited to, sound type
(e.g., impulsive vs. non-impulsive), signal characteristics, the
species, age, and sex class (e.g., adult male vs. mom with calf),
duration of exposure, the distance between the noise source and the
animal, received levels, behavioral state at time of exposure, and
previous history with exposure (Wartzok et al., 2004; Southall et al.,
2007). In general, sudden, high-intensity sounds can cause hearing
loss, as can longer exposures to lower-intensity sounds. Moreover, any
temporary or permanent loss of hearing, if it occurs at all, would
occur almost exclusively for noise within an animal's hearing range.
Below, we describe the specific manifestations of acoustic effects that
may occur based on the activities proposed by Coeur.
Richardson et al. (1995) described zones of increasing effect
intensity that might be expected to occur with distance from a source,
assuming that the signal is within an animal's hearing range. First (at
the greatest distance) is the area within which the acoustic signal
would be audible (potentially perceived) to the animal but not strong
enough to elicit any overt behavioral or
[[Page 23072]]
physiological response. The next zone (closer to the receiving animal)
corresponds to the area where the signal is audible to the animal and
sufficiently intense to elicit behavioral or physiological
responsiveness. The third is a zone within which, for high-intensity
signals, the received level is sufficient to cause discomfort or tissue
damage to auditory or other systems. Overlaying these zones to some
extent is the area within which masking (i.e., when a sound interferes
with or masks an animal's ability to detect a signal of interest above
the absolute hearing threshold) may occur; the masking zone may vary
widely in size.
Below, we provide additional details regarding the potential
impacts on marine mammals and their habitat from noise in general,
starting with hearing impairment, as well as from the specific
activities that Coeur plans to conduct, to the degree it is available.
Hearing Threshold Shifts
NMFS defines a noise-induced threshold shift (TS) as a change,
usually an increase, in the audibility threshold at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018, 2024). The amount
of threshold shift 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), the 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, the time to recovery (seconds to minutes
or hours to days), the frequency range of the exposure (i.e., spectral
content), the hearing frequency range of the exposed species relative
to the signal's frequency spectrum (i.e., how the 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).
Temporary Threshold Shift
A temporary threshold shift (TTS) is a temporary, reversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS, 2024). It is not considered an auditory injury
(AUD INJ). Based on data from marine mammal TTS measurements (see
Southall et al., 2007, 2019), a TTS of 6 dB is considered the minimum
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Finneran et
al., 2000, 2002; Schlundt et al., 2000). As described by Finneran
(2015), marine mammal studies have shown that the amount of TTS
increases with the 24-hour cumulative sound exposure level
(SEL<INF>24</INF>) in an accelerating fashion: at low exposures with
lower SEL<INF>24</INF>, the amount of TTS is typically small, and the
growth curves have shallow slopes. At higher SEL<INF>24</INF>
exposures, the growth curves become steeper and approach a linear
relationship with the sound exposure level (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 more impactful (similar to those discussed in
auditory masking, below). For example, a marine mammal may readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that occurs while the animal is traveling
through the open ocean, where ambient noise is lower and competing
sounds are fewer. Alternatively, a larger amount and a longer duration
of sustained TTS during critical communication periods (e.g., for
successful mother-calf interactions) could have more severe impacts. We
note that reduced hearing sensitivity, as a simple function of aging,
has been observed in marine mammals, as well as in humans and other
taxa (Southall et al., 2007), suggesting that strategies exist to cope
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, so the sound must be louder to be heard. In
terrestrial and marine mammals, TTS can last from minutes to hours (in
cases of strong TTS) (Finneran, 2015). 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, northern elephant
seals (Mirounga angustirostris), bearded seals (Erignathus barbatus),
and California sea lions (Kastak et al., 1999, 2007; Kastelein et al.,
2019b, 2019c, 2021, 2022a, 2022b; Reichmuth et al., 2019; Sills et al.,
2020). TTS was not observed in spotted (Phoca largha) and ringed (Pusa
hispida) seals exposed to single airgun impulse sounds at levels
matching previous predictions of TTS onset (Reichmuth et al., 2016).
These studies examine hearing thresholds in marine mammals before and
after exposure to intense or long-duration sound. 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 depend on the exposure frequency.
Sounds below the region of best sensitivity for a species or hearing
group are less hazardous than those 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 lower than that 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,
SEL<INF>24</INF>, will overestimate the amount of TTS from intermittent
exposures, such as sonars and impulsive sources. Nachtigall et al.
(2018) describe measurements of hearing sensitivity of multiple
odontocete species (bottlenose dolphin, harbor porpoise, beluga, and
false killer whale (Pseudorca crassidens)) when a warning sound
preceded a relatively loud 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 enable conditioned hearing
reduction and filtering of low-frequency ambient noise, including
increased stiffness and control of
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middle-ear structures, as well as placement of inner-ear structures
(Ketten et al., 2021). Data available on noise-induced hearing loss for
mysticetes are currently lacking (NMFS, 2024). Additionally, the
existing marine mammal TTS data are limited to a small number of
individuals within these species.
Relationships between TTS and AUD INJ thresholds have not been
studied in marine mammals, and there are no measured PTS data for
cetaceans, but such relationships are assumed to be similar to those in
humans and other terrestrial mammals. AUD INJ typically occurs at
exposure levels at least several dB above that inducing mild TTS (e.g.,
a 40-dB threshold shift approximates AUD INJ 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 AUD INJ 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 AUD INJ 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 AUD INJ as
compared with TTS, it is considerably less likely that AUD INJ could
occur.
Auditory Injury
NMFS (2024) defines AUD INJ as damage to the inner ear that can
result in tissue destruction, such as loss of cochlear neuron synapses
or auditory neuropathy (Houser, 2021; Finneran, 2024). AUD INJ may or
may not result in a permanent threshold shift (PTS). PTS is
subsequently defined 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 generally affects only a limited frequency
range, and animals with PTS exhibit some hearing loss at the relevant
frequencies; typically, animals with PTS or other AUD INJ 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 the onset of PTS (see Ward et al., 1958,
1959; Ward, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et al.,
1996; Henderson et al., 2008). However, a variety of terrestrial and
marine mammal studies (see Ward et al., 1958; Ward et al., 1959; Ward,
1960; Miller et al., 1963; Kryter et al., 1966; Finneran et al., 2007;
Kastelein et al., 2013) indicate that threshold shifts of up to 40 to
50 dB (measured a few minutes after exposure) may be induced without
resulting in PTS. PTS levels for marine mammals are estimates; with the
exception of a single study unintentionally inducing PTS in a harbor
seal (Kastak et al., 2008), no empirical data measure PTS in marine
mammals largely due to the fact that, for various ethical reasons,
experiments involving anthropogenic noise exposure at levels inducing
AUD INJ are not typically pursued or authorized (NMFS, 2024). NMFS has
set the PTS onset as a threshold shift of 40 dB.
However, after sound exposure ceases or between successive sound
exposures, there is potential for recovery from hearing loss. Thus,
because a threshold shift is measured a few minutes after noise
exposure does not mean that those initial shifts are persistent (i.e.,
no recovery). When initial threshold shifts fully recover back to
baseline hearing levels, these are considered TTS. PTS indicates there
is no full recovery back to baseline hearing levels; however, it does
not mean there is no recovery. Rather, PTS indicates incomplete hearing
recovery. Recovery depends on the initial threshold shift amount, the
frequency of the shift, the temporal pattern of exposure (e.g.,
exposure duration; continuous vs. intermittent), and the physiological
mechanisms underlying the shift (e.g., mechanical vs. metabolic). Since
recovery is complicated, our current AUD INJ onset criteria do not
account for the potential for recovery.
Behavioral Effects
Exposure to noise can also behaviorally disturb marine mammals to a
level that rises to the definition of harassment under the MMPA.
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 a behavioral disturbance,
and for responses that do, those of higher level or longer duration
have the potential to affect foraging, reproduction, or survival.
Behavioral disturbance may include subtle changes (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), and avoiding areas where sound sources are
located. In addition, 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, 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
predictable, unvarying sounds. 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 a general moderation in response to human disturbance (Bejder et
al., 2009). The opposite process is sensitization, in which an
unpleasant experience leads an animal to subsequently respond at lower
levels of exposure, often in the form of avoidance.
As noted above, behavioral state may affect the type of response.
For example, resting animals may show greater behavioral change in
response to disturbing sound levels compared to
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animals that are highly motivated to remain in an area for feeding
(Richardson et al., 1995; Wartzok et al., 2004; National Research
Council (NRC), 2005). Controlled experiments with captive marine
mammals have shown 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 how any given sound in a
particular instance might affect marine mammals perceiving it (e.g.,
Erbe et al., 2019). If a marine mammal briefly reacts to an underwater
sound by changing its behavior or moving a small distance, the
resulting change is unlikely to be significant to the individual, let
alone the stock or population. 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 responses, which we describe in
greater detail here, including alterations in dive and foraging
behavior, effects on breathing, interference with or alteration of
vocalizations, avoidance, and flight.
Avoidance and Displacement
Changes in dive behavior can vary widely and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et
al., 2004; Goldbogen et al., 2013a, 2013b; Blair et al., 2016).
Variations in dive behavior may reflect interruptions in biologically
significant activities (e.g., foraging) or they may be of little
biological significance. The impact of an alteration in dive behavior
resulting from acoustic exposure depends on what the animal is doing at
the time of exposure and on the type and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al.,
2007). Determining whether foraging disruptions incur fitness
consequences would require information on, or estimates of, the
energetic requirements of affected individuals; the relationships
between prey availability, foraging effort, and success; and the
animal's life history stage.
Respiration rates vary naturally with different behaviors, and
alterations in breathing rate, as a function of acoustic exposure, can
be expected to co-occur with other behavioral responses, such as a
flight response or changes 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 of 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 rates increased in
response to pile driving sounds at and above a received broadband SPL
of 136 dB (zero-peak SPL: 151 dB re 1 [mu]Pa; SEL of a single strike
(SEL<INF>ss</INF>): 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 due to the presence of a sound or other stressors and is
one of the most obvious manifestations of disturbance in marine mammals
(Richardson et al., 1995). Avoidance 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 the abundance or distribution patterns of the
affected species in the affected region if habituation to 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, with
directed, rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
its intensity (e.g., directed movement and travel rate). Relatively
little information exists on the flight responses of marine mammals to
anthropogenic signals, although observations of flight responses to the
presence of predators have been made (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 affect marine mammals in more
subtle ways. Increased vigilance may incur costs through attentional
diversion (i.e., when a response requires heightened vigilance, it may
come at the expense of reduced attention to other critical behaviors,
such as foraging or resting). These effects have generally not been
demonstrated in marine mammals, but studies of 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 reductions in fitness (e.g., declines in
body condition) and subsequent reductions 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 result in sleep deprivation or stress.
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, is more likely to be significant if it lasts more than one
diel cycle or recurs on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than one 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
multiple days does not necessarily mean that individual animals are
exposed to activity-related stressors for multiple days, or, further,
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that they are exposed in a manner that results in sustained, multi-day,
substantive behavioral responses.
Physiological Stress Responses
An animal's perception of a threat may be sufficient to trigger
stress responses that include some combination of behavioral, autonomic
nervous system, neuroendocrine, and immune responses (e.g., Selye,
1950; Moberg, 2000). In many cases, an animal's first and sometimes
most economical response (in terms of energetic costs) 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 pituitary hormone secretion have been implicated in
reproductive failure, altered metabolism, reduced immune competence,
and behavioral disturbances (e.g., Moberg, 1987; Blecha, 2000).
Increases in glucocorticoid levels are also associated 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 its glycogen
stores, which 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 energy
reserves to a sufficient level 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; Ayres et al., 2012; Yang
et al., 2022). Stress responses from 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 (Eubalaena glacialis). In addition,
Lemos et al. (2022) observed a correlation between higher levels of
fecal glucocorticoid metabolite concentrations (indicative of a stress
response) and vessel traffic in gray whales. Yang et al. (2022) studied
behavioral and physiological responses in captive bottlenose dolphins
exposed to playbacks of ``pile-driving-like'' impulsive sounds, finding
significant changes in cortisol and other physiological indicators, but
only minor behavioral changes. 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 some of these responses may be classified as ``distress.'' In
addition, any animal experiencing TTS would likely also experience
stress responses (NRC, 2005); however, distress is unlikely to result
from this Coeur project based on observations of marine mammals during
previous, similar construction projects.
Vocalizations and 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 specific frequencies for marine
mammals that rely on 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
acoustic sensors or environment are severely masked could also be
impaired in 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).
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 (toothed whales) but are more likely to
affect the 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 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, including modifications of the
signal's acoustic properties or the signaling behavior (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. Few studies have
addressed real-world masking sounds likely to be experienced by marine
mammals in the wild (e.g., Branstetter et al., 2013).
Masking occurs in the frequency band the animals use and is more
likely to occur in the presence of broadband, relatively continuous
noise sources, such as vibratory pile removal or installation. The
energy distribution of pile-driving sound spans a broad frequency
spectrum and is expected to fall within the audible range of marine
mammals present in the project area. Since noises generated from the
proposed construction activities are mostly concentrated at low
frequencies (<2 kHz), these activities likely have less effect on mid-
frequency echolocation sounds produced by odontocetes (toothed whales).
However, lower-frequency noises are more likely to
[[Page 23076]]
affect the detection of communication calls and other potentially
important natural sounds, such as surf and prey noise. Low-frequency
noise may also affect communication signals when they occur near the
noise band, thereby reducing the communication space of animals (e.g.,
Clark et al., 2009) and increasing stress levels (e.g., Holt et al.,
2009). Unlike TS, masking, which can occur over large temporal and
spatial scales, can potentially affect species at the population,
community, or even ecosystem levels, in addition to the individual
level. Masking affects both senders and receivers of signals and, at
higher levels and for longer durations, could have long-term chronic
effects on marine mammal species and populations. However, the noise
generated by the Coeur's proposed activities would occur only
intermittently, spanning an estimated 33 days during the authorization
period, and in a relatively small area focused around the proposed
construction site. Thus, while Coeur's proposed activities may mask
some acoustic signals 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
affected.
While in some cases marine mammals have exhibited little to no
obviously detectable response to certain common or routine
industrialized activities (Cornick et al., 2011; Horsley and Larson,
2023), some animals may, at times, be exposed to received levels of
sound above the Level B harassment thresholds during the proposed
project.
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 across any of these modes and may result from a need to
compete with increased 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 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 to lower the
bandwidth, peak frequency, and center frequency of their vocalizations
in the presence of increased 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 that exposed them to vessel noise, have been
observed to increase their vocalization rate and produce louder signals
during periods of increased outboard engine noise (Dahlheim and
Castellote, 2016). Alternatively, in some cases, animals may cease
sound production during the production of aversive signals (Bowles et
al., 1994; Wisniewska et al., 2018).
Under certain circumstances, marine mammals that experience
significant masking could also be impaired in maximizing their
performance fitness for survival and reproduction. Therefore, when the
coincident (masking) sound is human-made, it may be considered
harassment if it disrupts or alters 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 associated with
harassment). Therefore, under certain circumstances, marine mammals
whose acoustic sensors or environments are severely masked could also
be impaired in maximizing their performance fitness for survival and
reproduction.
Airborne Acoustic Effects
Pinnipeds near the project site could be exposed to airborne sounds
associated with construction activities, depending on their distance
from the activities, which could cause behavioral harassment. Although
pinnipeds haul out in Berners Bay, incidents of take resulting solely
from airborne sound are unlikely given the distance between the
proposed project area and the known haul-out locations, as well as the
timing of the project (8 to 10 weeks beginning July 1, 2026). For
example, during the July 12 aerial surveys conducted by NMFS and the
University of Alaska Fairbanks (UAF), harbor seals were observed out of
the water only on the river sandbars, which are approximately 2,880 m
from the Kensington Dock (Blejwas and Mathews, 2005). As for Steller
sea lions, Womble and Sigler (2006) reported the species was found in
Berners Bay only during April and May. Cetaceans are not expected to be
exposed to airborne sounds that would result in harassment as defined
under the MMPA.
We recognize that pinnipeds in the water may be exposed to airborne
sounds that could result in behavioral harassment when they lift their
heads above the water or when they haul out. Most likely, airborne
sound would cause behavioral responses similar to those discussed above
for underwater sound. For instance, anthropogenic sound could cause
hauled-out pinnipeds to exhibit changes in their normal behavior, such
as a reduction in vocalizations, or to flush from haulouts, temporarily
abandon the area, and/or move further from the source. However, these
animals would previously have been ``taken'' because of exposure to
underwater sound above 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 additional incidental take resulting from airborne
sound for pinnipeds is warranted, and airborne sound is not discussed
further here.
Potential Effects on Marine Mammal Habitat
Coeur's proposed activities for the project could have localized,
temporary impacts on marine mammal habitat, including prey, due to
increased in-water noise levels. Increased noise levels may affect the
acoustic habitat and adversely affect marine mammal prey in the
vicinity of the project areas (see discussion below). Elevated levels
of underwater noise would ensonify the project areas where both fishes
and mammals occur and could affect foraging success. Additionally,
marine mammals may avoid the area during the proposed construction
activities; however, any displacement due to noise is expected to be
temporary and not to result in long-term effects on individuals or
populations.
The total area likely impacted by Coeur's proposed activities is
relatively small compared to the available habitat in Berners Bay and
Lynn Canal. Avoidance by potential prey (i.e., fish) of the immediate
areas due to increased noise is possible. The duration of fish and
marine mammal avoidance of this area after construction stops is
unknown, but a rapid return to normal recruitment, distribution, and
behavior is anticipated. Any behavioral avoidance by fish or marine
mammals of either disturbed area would still leave significant areas of
foraging habitat for fish and marine mammals in the nearby vicinity.
[[Page 23077]]
The proposed project would occur within the same footprint as the
existing marine infrastructure. The nearshore and intertidal habitats
where the proposed project would occur are in a remote area used only
for inbound and outbound materials and workforce for the Kensington
Mine, so vessel traffic is minimal. Temporary, intermittent, and short-
term habitat alteration may result from increased noise levels during
the proposed construction activities. Effects on marine mammal habitat
would be limited to temporary displacement from pile removal and
installation noise, and effects on prey species would be similarly
limited in time and space.
Water Quality
A temporary, localized reduction in water quality would occur due
to in-water construction activities. Most of this effect would occur
during the installation and removal of piles when the bottom sediments
are disturbed. The installation and removal of piles would disturb the
bottom sediments and may temporarily increase suspended sediment in the
project area. During pile extraction, sediment attached to the pile
moves vertically through the water column until gravity causes 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).
Impacts on water quality from DTH are expected to be similar to
those described for pile driving. Impacts on water quality would be
localized and temporary, with negligible impacts on marine mammal
habitat. Drilling would have negligible impacts on water quality from
sediment resuspension because the system would operate within a casing
set into the bedrock. The drill would collect excavated material inside
the apparatus, where it would be lifted to the surface and placed onto
a barge for subsequent disposal.
Effects on turbidity and sedimentation are expected to be short-
term, minor, and localized. Given the strong tidal currents in the
area, following completion of sediment-disturbing activities, suspended
sediments in the water column should dissipate and return to background
levels quickly in all construction scenarios. Turbidity in the water
column can reduce dissolved oxygen levels and irritate the gills of
prey fish 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 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 Berners Bay.
Potential Effects on Prey
Sound may affect marine mammals by altering the abundance,
behavior, or distribution of prey species (e.g., crustaceans,
cephalopods, fishes, zooplankton). Marine mammal prey varies by
species, season, and location, and for some, it is not well documented.
Studies regarding the effects of noise on known marine mammal prey are
described here.
Fishes use 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 and detect the motion of surrounding water
(Fay et al., 2008). The potential effects of noise on fishes depend on
the overlapping frequency range, distance from the sound source, water
depth of exposure, and species-specific hearing sensitivity, anatomy,
and physiology. Key impacts on fishes may include behavioral responses,
hearing damage, barotrauma (pressure-related injuries), and mortality.
Fish react to 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 their physiological state, 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
fishes (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., Pe[ntilde]a et
al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott et
al., 2012). More commonly, though, the impacts of noise on fishes are
temporary.
SPLs of sufficient strength have been known to cause injury to
fishes and fish mortality (summarized in Popper et al., 2014). However,
in most fish species, hair cells in the ear continuously regenerate,
and auditory function is likely restored when damaged cells are
replaced with new ones. Halvorsen et al. (2012b) showed that a TTS of
4-6 dB was recoverable within 24 hours in one species. Impacts would be
most severe when the individual fish is near the source, and the
exposure duration 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., 2012a;
Casper et al., 2013, 2017).
Fish populations in the proposed project area that serve as prey
for marine mammals could be temporarily affected by noise from pile
removal and installation. 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 in response to strong and/or intermittent sounds
that could harm fish. 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).
Zooplankton is a food source for several marine mammal species, as
well as a food source for fish that are then preyed upon by marine
mammals. Population effects on zooplankton could indirectly affect
marine mammals. Data are limited on the effects of underwater sound on
zooplankton species, particularly sound from construction (Erbe et al.,
2019). Popper and Hastings (2009) reviewed information on the effects
of human-generated sound and concluded that no substantive data are
available on whether sound levels from pile driving, seismic activity,
or other human-made sources would have physiological effects on
invertebrates. Any such effects would be limited to the area very near
(1 to 5 m) the sound source and would result in no
[[Page 23078]]
population effects because of the relatively small area affected at any
one time and the reproductive strategy of most zooplankton species
(short generation, high fecundity, and very high natural mortality). No
adverse impact on zooplankton populations is expected from the
specified activities, due in part to their large reproductive capacity
and naturally high levels of predation and mortality. Any mortalities
or impacts that might occur would be negligible.
The greatest potential impact on marine mammal prey during
construction would occur during impact pile driving and DTH. While
vibratory pile driving may elicit behavioral responses in fishes, such
as temporary avoidance of the area, it is unlikely to cause injuries to
fishes or have persistent effects on local fish populations. However,
in-water construction activities would only occur during daylight
hours, allowing fish to forage and transit the project area in the
evening. Moreover, construction would have minimal permanent and
temporary impacts on benthic invertebrate species, which are also a
marine mammal prey source.
Potential Effects on Foraging Habitat
The proposed project is not expected to result in any habitat-
related effects that could cause significant or long-term negative
consequences for individual marine mammals or their populations, since
installation and removal of in-water piles would be temporary and
intermittent. The total seafloor area affected by pile installation and
removal is relatively small compared to the available habitat just
outside the project area, extending into the remaining Berners Bay and
Lynn Canal. In addition, the project area does not overlap any ESA-
designated critical habitat, and the Berners Bay humpback whale BIA is
only active in April and May, which is outside the anticipated
timeframe for project activities. Additionally, any behavioral
avoidance by fish of the disturbed area would still leave significantly
large areas of fish and marine mammal foraging habitat throughout the
rest of Berners Bay and into Lynn Canal. As described in the preceding,
the potential for project construction to affect the availability of
prey for marine mammals or to meaningfully impact the quality of
physical or acoustic habitat is considered to be insignificant.
Therefore, the impacts of the projects are not likely to adversely
affect marine mammal foraging habitat in the proposed project area.
In summary, given the relatively small areas being affected, as
well as the temporary and mostly transitory nature of the proposed
construction activities, any adverse effects from Coeur's activities on
prey habitat or prey populations are expected to be minor and
temporary. The most likely impact on fishes at the project sites would
be temporary avoidance of the area. Any behavioral avoidance by fish in
the disturbed areas would still leave significantly large areas of fish
and marine mammal foraging habitat in the nearby vicinity. Thus, we
preliminarily conclude that the impacts of the specified activities are
not likely to have more than short-term adverse effects on any prey
habitat or populations of prey species. Further, any impacts on marine
mammal habitat are not expected to result in significant or long-term
consequences for individual marine mammals or to contribute to adverse
impacts on their populations.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
proposed for authorization through the 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 be limited to Level B harassment only, in
the form of behavioral reactions for individual marine mammals
resulting from exposure to acoustic sources (i.e., vibratory, impact,
and DTH pile driving). Based on the nature of the activity, Level A
harassment is neither anticipated nor proposed to be authorized.
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 that there is some reasonable potential for
marine mammals to 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. 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 in the Level A harassment section below.
Level B Harassment
Though significantly driven by the received level, the onset of
behavioral disturbance from anthropogenic noise exposure is also
informed to varying degrees by other factors. These factors are related
to the source or exposure context (e.g., frequency, predictability,
duty cycle, exposure duration, signal-to-noise ratio, distance to the
source) and the environment (e.g., bathymetry, other noise in the area,
predators in the area). Therefore, the receiving animal's hearing,
motivation, experience, demography, life stage, and depth can be
difficult to predict (e.g., Southall et al., 2007; Southall et al.,
2021; Ellison et al., 2012). Based on available science and the
practical need to use a threshold based on a predictable, measurable
metric for most activities, NMFS typically uses a generalized acoustic
threshold based on the 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 sound pressure levels (RMS SPL) of 120 dB (referenced to 1
micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile
driving, DTH
[[Page 23079]]
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. Level B harassment take estimates based on these
behavioral harassment thresholds potentially include TTS, as, in most
cases, TTS likely occurs at distances from the source less than those
at which behavioral harassment may occur. TTS of a sufficient degree
can manifest as behavioral harassment and reduced hearing sensitivity,
and the potential reduction in opportunities to detect important
signals (conspecific communication, predators, prey) may result in
behavior patterns that would not otherwise occur.
Coeur's proposed activities include the use of continuous
(vibratory and DTH pile driving) and impulsive (impact and DTH pile
driving) sources; 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) (NMFS, 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). It includes updated thresholds
and updated weighting functions for each hearing group, provided in
table 4 below. The references, analysis, and methodology used to
develop the criteria are described in NMFS' 2024 Updated Technical
Guidance, available at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>-other-
acoustic-tools.
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.
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 criterion 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
better reflect International Organization for Standardization (ISO) standards (ISO, 2017). The subscript
``flat'' is being included to indicate that peak sound pressures 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, action proponents should indicate the conditions
under which these criteria would be exceeded.
Ensonified Area
Here, we describe the operational and environmental parameters of
the activity used to estimate the area ensonified above the acoustic
thresholds, including source levels and transmission loss coefficient.
The sound field in the project area consists of existing background
noise and additional construction noise from the proposed project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., vibratory pile removal,
vibratory pile driving, impact pile driving, and DTH). The source
levels assumed for both removal and installation activities are based
on reviews of measurements of piles of the same or similar types and
dimensions available in scientific literature and from similar coastal
construction projects. The source levels for the piles and activities
(i.e., installation or removal) are presented in table 5. All
construction methods would use a bubble curtain, thereby reducing the
sound source levels. However, the source levels in table 5 are all
unattenuated, and do not include the anticipated 5 dB attenuation from
the use of a bubble curtain.
Table 5--Proxy Sound Source Levels for Pile Sizes and Driving Methods
--------------------------------------------------------------------------------------------------------------------------------------------------------
Unattenuated Source Levels \1\
Source Construction method ------------------------------------------------- Source-Level Reference
SPLRMS SEL SPLPK
--------------------------------------------------------------------------------------------------------------------------------------------------------
Template and Batter piles (24'' steel Vibratory.................. 163 NA NA Naval Base Kitsap Bangor Test
pipe). Pile (Navy, 2012) and EHW-2
(Navy, 2013), Gustavus (Miner,
2020).
Batter piles (24'' steel pipe).......... Impact..................... 190 177 203 (Caltrans, 2015); Stockton WWTP,
CA; Bradshaw Bridge, CA; Rodeo
Dock, CA; Tongue Point Pier,
OR; Cleer Creek WWTP, CA; SR
520 Test Pile, WA; Portland
Light Rail, OR; Port of
Coeyman, NY; Pritchard Lake,
CA; Amorco Wharf, CA; 5th
Street Bridge, CA; Schuyler
Heim Bridge, CA; Tanana River,
AK, NBK EHW2, WA; Crescent
City, CA; Avon Wharf, CA;
Orwood Bridge Replacement, CA;
Tesoro Amorco Wharf, CA; USCG
Floating Dock, CA; Norfolk, VA;
Plains Terminal, CA.
Vertical piles (30'' steel pipe)........ Vibratory.................. 166 NA NA Denes et al., (2016) (Auke Bay,
Ketchikan, Kake), Edmonds Ferry
Terminal (Laughlin, 2011,
2017), Colman Dock--Seattle
Ferry Terminal (Laughlin,
2012), Kodiak Pier 3 (PND
Engineers, 2015).
[[Page 23080]]
Vertical piles (30'' steel pipe)........ Impact..................... 190 177 210 Caltrans 2015; Richmond/San
Rafael Bridge, CA; Siuslaw
River Bridge, OR; SR520 Test
Pile, WA; Avon Wharf, CA;
Fender Replacement, Redwood
City, CA.
Vertical piles (48'' steel pipe)........ Vibratory.................. 171 NA NA Naval Base Kitsap Bangor Test
Pile (Navy, 2012) and EHW-2
(Navy, 2013).
Vertical piles (48'' steel pipe)........ Impact..................... 192 179 213 Caltrans (2020) Project: Alameda
Bay, CA; Russian River
Geyserville, CA; Terminal
Replacement, Antioch, CA; AVON
Wharf, CA; Naval Base Kitsap
EHW, WA; Philadelphia, PA.
Rock Anchors (6'' drill hole through DTH........................ 156 144 170 Reyff & Heyvaert (2019), Reyff
10'' casing inside pile). (2020).\2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Average underwater SPLRMS, SEL, and SPLPK sound pressure levels are reported in dB re: 1 micropascal ([mu]Pa) @10 meters. These levels are
unattenuated and do not include the 5 dB reduction from bubble curtains during vibratory, impact, and DTH operations.
\2\ NMFS (2022). NMFS Acoustic Guidance for Assessment of Down-the-Hole (DTH) Systems. U.S. Department of Commerce, National Oceanic and Atmospheric
Administration, National Marine Fisheries Service.
Transmission loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, bottom composition, and
topography. The general formula for underwater TL is:
TL = B * Log<INF>10</INF> (R<INF>1</INF>/R<INF>2</INF>),
Where:
TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading, equals
15
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.
This formula neglects loss due to scattering and absorption, which
is assumed to be zero here. The degree to which underwater sound
propagates away from a sound source depends on various factors, most
notably the water bathymetry and the presence or absence of reflective
or absorptive conditions, including in-water structures and sediments.
Spherical spreading occurs in a perfectly unobstructed (free-field)
environment not limited by depth or water surface, resulting in a -6 dB
reduction in sound level for each doubling of distance from the source
(20*log[range]). Cylindrical spreading occurs in an environment in
which sound propagation is bounded by the water surface and sea bottom,
resulting in a reduction of 3 dB in sound level for each doubling of
distance from the source (10*log[range]). A practical spreading value
of 15 is often used in coastal conditions, such as at the Coeur project
site. In these environments, sound waves repeatedly reflect off the
surface and bottom, reflecting an expected propagation environment
between spherical and cylindrical spreading-loss conditions. Therefore,
the default coefficient of 15 is used to calculate distances to the
Level A harassment and Level B harassment thresholds.
Assuming practicable spreading and other assumptions regarding the
source characteristics and operational logistics (e.g., source level,
number of strikes per pile, number of piles per day), Coeur calculated
distances to the Level A harassment and Level B harassment thresholds
and associated ensonified areas. Because an ensonified area associated
with Level A harassment is more technically challenging to predict
given the accounting for a cumulative energy component that changes
over time, to assist applicants in assessing the potential for Level A
harassment without the need for complex modeling, NMFS developed an
optional User Spreadsheet tool to accompany the 2024 Updated Technical
Guidance (see <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>-other-acoustic-
tools). This relatively simple tool can be used to calculate a Level A
harassment isopleth distance for use in conjunction with marine mammal
density or occurrence data to predict the amount of take that may occur
incidental to an activity. We note that, because of assumptions in the
methods underlying this spreadsheet tool, we anticipate that the
resulting isopleths would typically be overestimates, potentially
leading to an overestimate of potential exposures from Level A
harassment. However, this optional tool offers a practical alternative
for estimating isopleth distances when more sophisticated modeling
methods are unavailable or are impractical. For stationary sources such
as vibratory pile driving and removal, impact pile driving, or DTH, the
optional User Spreadsheet tool predicts the distance at which, if a
marine mammal remained at that distance for the duration of the
activity within 24 hours, it would be expected to incur AUD INJ. Inputs
used in the optional User Spreadsheet tool are included in table 6.
[[Page 23081]]
Table 6--User Spreadsheet Input Parameters Used for Calculating Level A Harassment Isopleths
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory pile removal Vibratory pile installation Impact pile installation DTH
------------------------------------------------------------------------------------------------------------------------------------------------------------------ installation
Template piles Batter piles Template piles Batter piles Batter piles ---------------
Equipment type (24'' steel (24'' steel Vertical piles (24'' steel (24'' steel Vertical piles Vertical piles (24'' steel Vertical piles Vertical piles Rock anchors
pipe or pipe or (30'' steel pipe or pipe or (30'' steel (48'' steel pipe or (30'' steel (48'' steel (6'' drill
equivalent) equivalent) pipe) equivalent) equivalent) pipe) pipe) equivalent) pipe) pipe) hole)
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet tab used.................................. A.1) Vibratory pile driving
A.1) Vibratory pile driving
E.1) Impact pile driving E.2) DTH
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Source level (dB re: 1 [mu]Pa) \1\.................... 158 RMS 158 RMS 161 RMS 158 RMS 158 RMS 161 RMS 166 RMS 172 SEL 172 SEL 174 SEL 139 SEL
198 Peak 205 Peak 208 Peak 165 Peak
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Weighting factor adjustment (kH)...................... 2.5
2.5
2 2
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Duration to drive a single pile (minutes)............. 30 30 30 30 30 30 30 .............. .............. .............. 120
Strike rate (ave. strikes per second)................. .............. .............. ............... .............. .............. .............. ............... .............. .............. .............. 30
Number of strikes per pile............................ .............. .............. ............... .............. .............. .............. ............... 600 600 600 ..............
Number of piles per day............................... 5 2 1 5 1 1 1 2 1 1 1
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Propagation (xLogR)................................... 15
15
15 15
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Distance of SPL measurement (m)....................... 10
10
10 10
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Vibratory removal/installation, impact, and DTH source levels all assume 5 dB attenuation reduction from the use of bubble curtains.
[[Page 23082]]
Using practical spreading and the source level assumptions
identified in table 6, Coeur calculated, and NMFS has carried forward
into this analysis, the distances to the Level A harassment and Level B
harassment thresholds for marine mammals for this project (table 7).
Table 7--Calculated Distances to Level A Harassment and Level B Harassment Thresholds by Marine Mammal Hearing Group and Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment zone (m) All marine mammals
Source Method ----------------------------------------------------------------- Level B harassment
LFC HFC VHFC PW OW zone (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Pile Driving/Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
Template pile (24'' steel)............. Install................... 10.7 4.1 8.8 13.8 4.6 3,414.5
Template pile (24'' steel)............. Removal................... 10.7 4.1 8.8 13.8 4.6 3,414.5
Batter pile (24'' steel)............... Install................... 3.7 1.4 3.0 4.7 1.6 3,414.5
Batter pile (24'' steel)............... Removal (old)............. 5.8 2.2 4.8 7.5 2.5 3,414.5
Vertical pile (30'' round steel)....... Install................... 5.8 2.2 4.7 7.5 2.5 5,411.7
Vertical pile (30'' round steel)....... Removal (old)............. 5.8 2.2 4.7 7.5 2.5 5,411.7
Vertical pile (48'' round steel)....... Installation.............. 12.5 4.8 10.2 16.1 5.4 11,659.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
Batter pile (24'' steel)............... Install................... 207.6 26.5 321.3 184.4 68.8 464.2
Vertical pile (30'' round steel)....... Install................... 130.8 16.7 202.4 116.2 43.3 464.2
Vertical pile (48'' round steel)....... Install................... 177.8 22.7 275.1 157.9 58.9 631.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
DTH Drilling
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rock anchors (6'' drill hole through Install................... 41.8 5.3 64.6 37.1 13.8 1,165.9
10'' casing inside pile).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: All distances are calculated using attenuated sound source levels.
Abbreviations: LFC = Low-Frequency Cetacean; HFC = High-Frequency Cetacean; VHFC = Very High-Frequency Cetacean; PW = Phocid pinniped (in-water); and
OW = Otariid pinniped (in-water).
Marine Mammal Occurrence
In this section, we provide information on the anticipated
occurrence of marine mammals present in the project area. This
occurrence information then informs the take calculations in the
following section (see Take Estimation and table 9).
For all species, the best available scientific information was
considered to estimate occurrence. Since no animal density data is
available for Berners Bay, Coeur used marine mammal monitoring reports
from both Berners Bay (Blejwas and Mathews, 2005; Coeur Alaska, Inc.,
2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022,
2023, 2024, and 2025) and Southeast Alaska (Dahlheim et al., 2009) to
develop site-specific occurrence estimates for each species. Here,
sighting rates (the total number of individuals per day of monitoring
effort) for each marine mammal species were calculated for each year,
and averaged across years (table 8). Because the 2011-2025 Coeur
Alaska, Inc., surveys were conducted during spring (April and May) to
align with the eulachon and herring spawning season, species presence
was likely higher than in summer months when this project is
anticipated to begin (July).
Table 8--Estimated Occurrence of Marine Mammal Species
------------------------------------------------------------------------
Daily
estimated
Species sighting rate
\1\
------------------------------------------------------------------------
Dall's porpoise......................................... 3.04
Harbor porpoise......................................... 3.17
Harbor seal............................................. 40.98
Humpback whale.......................................... 11.29
Killer whale............................................ 1.71
Minke whale............................................. NA \2\
Steller sea lion........................................ 36.33
------------------------------------------------------------------------
\1\ Daily estimated sighting rates (the total number of individuals per
day of monitoring effort) were calculated for each year (2011-2025)
and averaged across years.
\2\ No minke whales were reported during the 2005 NMFS and UAF surveys
(Blejwas and Mathews, 2005) and the 2011-2025 Coeur Surveys. However,
minke whales may be present in the project area, based on two
sightings reported in Dahlheim et al. (2009).
Take Estimation
Here, we describe how the information provided above is synthesized
to produce a quantitative estimate of the take that is reasonably
likely to occur and is proposed for authorization.
Coeur estimated take by Level B harassment by multiplying the daily
estimated sighting rate for each species (table 8) by the anticipated
33 days of pile driving and DTH activity (33 days accounts for a
contingency of 10 percent to account for the possibility of
construction overages). Calculations were then rounded to the nearest
whole number. NMFS concurs with this method.
For Dall's porpoises, the daily estimated sighting rate (3.04) was
multiplied by 33 days of pile driving for a total of 100.32, which
rounds to 100 estimated takes by Level B harassment. Coeur requests,
and NMFS proposes to authorize 100 takes by Level B harassment of
Dall's porpoises.
For harbor porpoises, the daily estimated sighting rate (3.17)
multiplied by 33 days totals 104.61, which rounds to 105 estimated
takes. Therefore, Coeur requests, and NMFS proposes, to authorize 105
takes by Level B harassment of harbor porpoises.
For harbor seals, the daily estimated sighting rate (40.98)
multiplied by 33 days totals 1,352.34, which rounds to 1,352 estimated
takes. Therefore, Coeur requests, and NMFS proposes to authorize 1,352
takes by Level B harassment of harbor seals.
Multiple humpback whale stocks occur in the project area. Eighty-
nine percent of whales present in the Gulf of Alaska are expected to be
from the Hawai'i stock, 11 percent from the Mexico-North Pacific stock,
and less than 1 percent from the WNP stock (Wade, 2021). Therefore, the
total estimated take for each stock was calculated by multiplying the
daily estimated sighting rate (11.29) by 33 days of pile driving, then
multiplying by
[[Page 23083]]
the proportion of the stock that makes up the species (i.e., 89, 11, or
0.01 percent for the Hawai'i stock, the Mexico-North Pacific stock, and
the WNP stock, respectively). Based on this apportionment, Coeur
requests, and NMFS proposes, to authorize 332 takes by Level B
harassment for the Hawai'i stock, 41 takes by Level B harassment for
the Mexico-North Pacific stock, and 4 takes by Level B harassment for
the WNP stock.
For killer whales, the daily estimated sighting rate (1.71)
multiplied by 33 days totals 56.43, which rounds to 56 estimated takes.
Accordingly, Coeur requests, and NMFS proposes to authorize 56 takes by
Level B harassment of killer whales.
Although no minke whales were reported during the 2005 NMFS and UAF
surveys (Blejwas and Mathews, 2005) and the 2011-2025 Coeur Alaska,
Inc., surveys, the species may be present in the project area, based on
two sightings reported in Dahlheim et al. (2009). Therefore, Coeur
requests, and NMFS proposes to authorize two takes by Level B
harassment of minke whales.
For the Steller sea lion species, the daily estimated sighting rate
(36.33) multiplied by 33 days totals 1,198.89, which rounds to 1,199
estimated takes by Level B harassment. However, Steller sea lions are
divided into two stocks: the Eastern stock, a population east of the
144[deg] W longitude at Cape Suckling, AK, and the Western stock. While
most Steller sea lions in the project area would likely be from the
Eastern stock, distinguishing between the two stocks without tagging or
branding is impossible. Based on genetic data analyzed in Hastings et
al. (2020), 98.6 percent of animals in the project area are likely from
the Eastern stock, and 1.4 percent from the Western stock. Therefore,
1,199 estimated takes multiplied by 0.986 totals 1,182.21, which rounds
to 1,182; 1,199 estimated takes multiplied by 0.014 totals 16.79, which
rounds to 17. Therefore, Coeur requests, and NMFS proposes to authorize
1,182 takes by Level B harassment of the Eastern stock, and 17 takes by
Level B harassment of the Western stock.
Coeur proposes to implement shutdown zones that meet or exceed the
Level A harassment zone for all activities, and did not request take by
Level A harassment. NMFS anticipates that Coeur will be able to
effectively monitor and implement these shutdown zones, and, therefore,
NMFS neither anticipates nor proposes to authorize take by Level A
harassment.
Table 9 summarizes the proposed authorized takes, by Level B
harassment only, and the proposed take as a percentage of stock
abundance.
Table 9--Proposed Authorized Take by Level B Harassment and as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
Proposed authorized take
-------------------------------- Take as a
Common name Stock Total proposed percent of
Level B take stock abundance
----------------------------------------------------------------------------------------------------------------
Dall's porpoise...................... Alaska.................. 100 100 N/A
Harbor porpoise...................... Northern Southeast 105 105 6.49
Alaska Inland Waters.
Harbor seal.......................... Lynn Canal/Stephens 1,352 1,352 10.10
Passage.
Humpback whale....................... Hawai[revaps]i.......... 332 332 2.94
Mexico-North Pacific.... 41 41 NA
WNP..................... 4 4 0.37
Killer Whale......................... Eastern North Pacific 56 56 2.92
Alaska Resident.
Eastern Northern Pacific .............. .............. 18.54
Northern Resident.
Eastern North Pacific .............. .............. 9.54
Gulf of Alaska,
Aleutian Islands, and
Bering Sea Transient.
West Coast Transient.... .............. .............. 16.05
Minke whale.......................... Alaska.................. 2 2 NA
Steller sea lion..................... Western................. 17 17 0.03
Eastern................. 1,182 1,182 3.26
----------------------------------------------------------------------------------------------------------------
Proposed Mitigation
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
(ITAs) to include information about the availability and feasibility
(economic and technological) of equipment, methods, and the 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) How and to what degree the successful implementation of the
measure(s) is expected to reduce impacts on marine mammal species or
stocks and their habitat. This considers the nature of the potential
adverse impact being mitigated (likelihood, scope, range). It further
considers the likelihood that the measure would be effective if
implemented (probability of accomplishing the mitigating result if
implemented as planned), the likelihood of effective implementation
(probability implemented as planned); and
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost and impact on
operations.
The mitigation requirements described in the following were
proposed by Coeur in its adequate and complete application or are the
result of subsequent coordination between NMFS and Coeur. Coeur has
agreed that all the mitigation measures are practicable. NMFS has fully
reviewed the specified activities and the mitigation measures to
determine if the mitigation measures would result in the least
practicable adverse impact on marine mammals and their habitat, as
required by the MMPA, and has determined that the proposed measures are
appropriate. NMFS describes these below as proposed
[[Page 23084]]
mitigation requirements and has included them in the proposed IHA.
Establishment of Shutdown Zones
Coeur proposed, and NMFS would require, the establishment of
shutdown zones with radial distances, as identified in table 10, for
all construction 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) to minimize potential instances of AUD INJ
and more severe behavioral disturbances by delaying the start of an
activity if marine mammals are near the activity. Additionally, Coeur
would be required to shut down if an unauthorized species is present to
avoid taking it. Shutdown zones would be cleared before activities
begin and would vary by activity type and marine mammal hearing group.
The placement of up to two PSOs during all pile-driving activities
(as described in the Proposed Monitoring and Reporting section) would
ensure that the entire shutdown zone is visible. Should environmental
conditions deteriorate to the point that the entire shutdown zone is
not visible (e.g., fog, heavy rain), pile driving would be delayed
until the PSO is confident that marine mammals within the shutdown zone
can be detected. Limiting construction activities to daylight hours
only would also increase the detectability of marine mammals in the
area.
If pile driving is delayed or halted due to the presence of a
marine mammal, the activity may not begin or resume until either the
animal has voluntarily exited and been visually confirmed beyond the
shutdown zone, or 15 minutes have passed without re-detection of the
animal.
To avoid direct physical interaction with marine mammals during
construction activity, if a marine mammal approaches within 10 m for
activities other than pile driving, operations must cease, and vessels
must reduce speed to the minimum level necessary to maintain steerage
and safe working conditions, as needed to prevent direct physical
interaction.
Table 10--Shutdown Zones by Marine Mammal Hearing Group and Activity
----------------------------------------------------------------------------------------------------------------
Distance to shutdown zone (m)
Source Method ----------------------------------------------------------------
LFC HFC VHFC PW OW
----------------------------------------------------------------------------------------------------------------
Vibratory Pile Driving/Removal
----------------------------------------------------------------------------------------------------------------
Template pile (24'' steel)... Install......... 20 10 10 20 10
Template pile (24'' steel)... Removal......... 20 10 10 20 10
Batter pile (24'' steel)..... Install......... 10 10 10 10 10
Batter pile (24'' steel)..... Removal (old)... 10 10 10 10 10
Vertical pile (30'' round Install......... 10 10 10 10 10
steel).
Vertical pile (30'' round Removal (old)... 10 10 10 10 10
steel).
Vertical pile (48'' round Installation.... 20 10 20 20 10
steel).
----------------------------------------------------------------------------------------------------------------
Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
Batter pile (24'' steel)..... Install......... 210 30 330 190 70
Vertical pile (30'' round Install......... 140 20 210 120 50
steel).
Vertical pile (48'' round Install......... 180 30 280 160 60
steel).
----------------------------------------------------------------------------------------------------------------
DTH Drilling
----------------------------------------------------------------------------------------------------------------
Rock anchors (6'' drill hole Install......... 50 10 70 40 20
through 10'' casing inside
pile).
----------------------------------------------------------------------------------------------------------------
Abbreviations: LFC = Low-Frequency Cetacean; HFC = High-Frequency Cetacean; VHFC = Very High-Frequency Cetacean;
PW = Phocid pinniped (in-water); and OW = Otariid pinniped (in-water).
Pre- and Post-Activity Marine Mammal Monitoring
Monitoring would take place from 30 minutes prior to initiation of
pile driving or DTH activity (i.e., pre-start clearance monitoring)
through 30 minutes post-completion of pile driving or DTH activity. In
addition, monitoring for 30 minutes would take place whenever a break
in the specified activity (i.e., vibratory pile driving, impact pile
driving, or DTH) of 30 minutes or longer occurs. Pre-start clearance
monitoring would be conducted during periods of sufficient visibility
for the lead PSO to determine that the shutdown zones indicated in
table 10 are clear of marine mammals. Pile driving may commence
following 30 minutes of observation when the determination is made that
the shutdown zones are clear of marine mammals. If a marine mammal is
observed entering or within the shutdown zones, pile driving activity
must be delayed or halted. If pile driving is delayed or halted due to
the presence of a marine mammal, the activity may not commence or
resume until either the animal has voluntarily exited and been visually
confirmed beyond the shutdown zone, or 15 minutes have passed without
re-detection of the animal.
Soft-Start
Coeur would use soft-start techniques when impact pile driving.
Soft-start procedures provide additional protection for marine mammals
by issuing a warning and/or giving them a chance to leave the area
before the hammer operates at full capacity. 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
sets of reduced energy strikes. A soft start would be implemented at
the start of each day's impact pile driving, and at any time following
cessation of impact pile driving for a period of 30 minutes or longer.
Bubble Curtain
Coeur has proposed using a bubble curtain to reduce the extent of
the ensonified areas and the sound levels within them. A bubble curtain
would attenuate in-water construction noise during all the proposed
pile driving activities presented herein (i.e., vibratory, impact, and
DTH).
In summary, based on our evaluation of Coeur's proposed mitigation
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,
with particular focus on
[[Page 23085]]
rookeries, mating grounds, and similar areas of significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. Effective reporting is critical both for
compliance and ensuring the most value is obtained from the required
monitoring.
Monitoring and reporting requirements prescribed by NMFS should
help improve the 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.
The monitoring and reporting requirements described in the
following were proposed by Coeur in its adequate and complete
application or are the result of subsequent coordination between NMFS
and Coeur. Coeur has agreed to the requirements. NMFS describes these
below as requirements and has included them in the proposed IHA.
Visual Monitoring
All PSOs must be NMFS-approved, be independent of the activity
contractor, and have no other assigned tasks during monitoring periods.
At least one PSO would have prior experience performing the duties of a
PSO during construction activity pursuant to a NMFS-issued ITA. Coeur
would have one to two PSOs actively monitoring on-site at all times
during pile-driving and DTH activities. Where a team of two or more
PSOs is required, a lead observer or monitoring coordinator would be
designated. The lead observer would be required to have prior
experience working as a marine mammal observer during construction.
Other PSOs may substitute relevant experience, education (a degree in
biological science or a related field), or training for prior
experience performing the duties of a PSO. PSOs may also substitute
Alaska native traditional knowledge for experience. Additional PSOs may
be employed during periods of low or obstructed visibility to ensure
the entirety of the shutdown zone is monitored.
PSOs would also have the ability to conduct field observations and
collect data according to assigned protocols, including experience or
training in the field of identification of marine mammals, including
the identification of behaviors; sufficient training, orientation, or
experience with the construction operation to provide for personal
safety during observations; writing skills sufficient to prepare a
report of observations including but not limited to (1) the number and
species of marine mammals observed; (2) dates and times when in-water
construction activities were conducted; (3) dates, times, and reason
for implementation of mitigation (or why mitigation was not implemented
when required); (4) marine mammal behavior; and (5) the ability to
communicate orally, by radio, or in person with Project personnel to
provide real-time information on marine mammals observed in the area as
necessary.
Reporting
Coeur would be required to submit a draft report(s) on all
construction activities and marine mammal monitoring results to NMFS
within 90 days of the completion of monitoring, or 60 days prior to the
requested issuance of any subsequent IHAs or similar activity at the
same location, whichever comes first. The information required to be
collected and reported to NMFS is included in the draft IHA available
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 summary, the
report would include, but not be limited to, information regarding
activities that occurred, marine mammal sighting data, and whether
mitigative actions were taken or could not be taken. Coeur would also
be required to submit reports on any observed injured or dead marine
mammals. If the death or injury was clearly caused by the project
activities, Coeur would immediately cease the specified activities
until NMFS reviews the circumstances of the incident and determines
what, if any, additional measures are appropriate to ensure compliance
with the terms of the IHA. Coeur would not resume its activities until
notified by NMFS. Specific proposed mitigation, monitoring, and
reporting requirements can be found in the draft IHA 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>.
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 upon 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
[[Page 23086]]
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
the species listed in table 9, 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 on the size, status, or structure of any of these
species or stocks that would lead to a different analysis for this
activity.
Pile-driving activities (via vibratory, impact, and DTH) associated
with the project, as outlined previously, may disturb or displace
marine mammals. Specifically, the specified activities may result in
Level B harassment from underwater sounds generated from pile driving
and removal. Potential takes could occur if individual marine mammal
species are present in zones ensonified above the thresholds for Level
B harassment identified above (see table 7) when these activities are
underway.
Given the nature of the proposed activity, NMFS does not anticipate
serious injury or mortality to marine mammals from Coeur's proposed
project, even in the absence of required mitigation. Further, as stated
in the Proposed Mitigation section, Coeur would implement shutdown
zones that equal or exceed all the Level A harassment isopleths shown
in table 7. As such, take by Level A harassment of species occurring at
the proposed project site is neither anticipated nor proposed for
authorization.
For all species and stocks, take is expected to occur within a
limited area (adjacent to the project site) of the stock's range. The
intensity and duration of anticipated take by Level B harassment would
be minimized through the proposed mitigation measures described herein.
Furthermore, the amount of take proposed for authorization is small
compared to the relevant stock's abundance, even if every take occurred
to separate individuals within a stock.
Behavioral responses of marine mammals to vibratory, impact, and
DTH pile driving at the project site, if any, are expected to be mild,
short-term, and temporary. Given that pile-driving activities would
occur over an estimated 33 days spanning 8 to 10 weeks beginning July
1, 2026, any harassment is expected to be temporary and intermittent.
Marine mammals within the Level B harassment zones may not show any
visual cues that they are disturbed by activities, or they may become
alert, avoid the area, leave the area, or display other mild responses
that are not observable, such as changes in vocalization patterns.
Additionally, many of the species potentially present in the region
would be present only temporarily, due to seasonal patterns or active
transit between other habitats. Most likely, during pile-driving
activities, individuals would be expected to move away from the sound
source and be temporarily displaced from the pile-driving area.
However, this reaction has been observed primarily associated with
impact pile driving. Vibratory pile driving associated with the
proposed project may produce sound at distances of many kilometers from
the project site, thus overlapping with some likely less-disturbed
habitats. However, the remote project site is located within Slate
Cove, Berners Bay, which is used only for importing supplies and fuel
and for exporting mined ore concentrate from the Kensington Mine.
Animals disturbed by project sounds are expected to avoid the immediate
area and use nearby higher-quality habitats in and beyond Berners Bay
and Lynn Canal. Pinnipeds in the area would be at their haul-outs
outside the project area, and no in-air harassment is anticipated from
construction.
The potential for harassment is minimized by implementing the
proposed mitigation measures. During all impact driving, the
implementation of soft-start procedures and the monitoring of
established shutdown zones by trained and qualified PSOs shall be
required, thereby significantly reducing any possibility of injury.
Given sufficient notice through soft start (for impact driving), marine
mammals are expected to move away from an irritating sound source
before it becomes potentially injurious.
Any impact on marine mammal prey that would occur during Coeur's
proposed activities would have, at most, short-term effects on the
foraging of individual marine mammals, and likely have no effect on the
populations of marine mammals as a whole. Indirect effects on marine
mammal prey during construction are expected to be minor and unlikely,
especially since the proposed project is outside of the spring spawning
season of eulachon and Pacific herring. Therefore, we do not expect the
project to cause substantial individual- or population-level impacts on
marine mammals, nor to affect annual recruitment or survival rates.
In addition, the area likely impacted by the proposed project is
relatively small compared to the available habitat in the surrounding
waters of Lynn Canal, the Tongass Narrows, and in Southeast Alaska in
general. Although Berners Bay is part of an identified BIA for feeding
humpback whales (NOAA, 2024), the BIA's timing (April and May) does not
overlap with the proposed in-water construction schedule (beginning
after July 1 and lasting approximately 8 to 10 weeks). Finally, there
is no ESA-designated critical habitat in the area for humpback whales
or the Western DPS of Steller sea lions.
In summary and as described above, the following factors primarily
support our preliminary determination that the potential 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 Level A harassment, serious injury or mortality is
anticipated or proposed for authorization incidental to the project;
<bullet> The anticipated incidents of Level B harassment would
consist of, at worst, temporary modifications in behavior that would
not result in fitness impacts on individuals;
<bullet> The area affected by the specified activity is very small
relative to the overall habitat ranges of all species, and does not
include any rookeries, ESA-designated critical habitat, or active BIAs;
<bullet> Effects on marine mammal prey species 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 adverse impacts on
their populations; and
<bullet> The proposed mitigation measures, such as soft-starts and
shutdowns, are expected to reduce the potential effects of the
specified activity on marine mammals.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity would have a negligible impact
on all affected marine mammal species or stocks.
Small Numbers
As noted previously, only take of small numbers of marine mammals
may be authorized under 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, so, in practice, when estimated numbers
are available, NMFS
[[Page 23087]]
compares the number of individuals taken to the most appropriate
abundance estimate for the relevant species or stock in determining
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 (see 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.
Our analysis shows that less than one-third of each affected stock
could be taken by harassment. The number of animals proposed to be
taken from these stocks would be considered small relative to the
relevant stock's abundance, even if each estimated taking occurred to a
new individual--an unlikely scenario.
There is no current abundance estimate of the Mexico-North Pacific
stock of the humpback whale (Young et al., 2026). To determine the
number of animals belonging to the Mexico-North Pacific stock in
Southeast Alaska in the summer, the abundance estimate for each feeding
area was multiplied by the probability of movement between that feeding
area and the Mexican wintering area, as estimated by Wade (2021), and
then added together. This resulted in an estimate of 918 humpback
whales in the Mexico-North Pacific stock (Young et al., 2026).
Therefore, 41 takes by Level B harassment proposed for authorization
represent small numbers of this stock, even if each take occurred to a
new individual.
There is no current abundance estimate of the Alaska stock of minke
whale, but an abundance of 2,020 individuals was estimated on the
eastern Bering shelf based on a 2010 survey (Friday et al., 2013; Young
et al., 2024). Therefore, the two takes by Level B harassment proposed
for authorization represent small numbers of this stock, even if each
take occurred to a new individual.
There is no current abundance estimate of the Alaska stock of
Dall's porpoise (Young et al., 2026), but a minimum population estimate
for this stock is assumed to be equal to or greater than 13,110 based
on a 2015 vessel-based abundance estimate calculated by Rone et al.
(2017) in the Gulf of Alaska. Therefore, 100 takes by Level B
harassment proposed for authorization represent small numbers of this
stock, even if each take occurred to a new individual.
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.
Alaska Natives have traditionally harvested subsistence resources,
including marine mammals (Steller sea lions and harbor seals), for
hundreds of years. This includes the harvest of harbor seals near
Berners Bay (ADF&G 2009a,b). In recent decades, hunting levels have
declined to historically low levels (Wolfe et al., 2013). The last
available report of marine mammal harvest in Southeast Alaska was in
2012 and included harbor seals (595) and sea lions (9) (Wolfe et al.,
2013); however, this report did not specify subsistence activity in
Berners Bay. Moreover, although Steller sea lions and harbor seals
regularly haul out in Berners Bay, though well outside the project
area, Coeur, which has been operating the Kensington Mine since 2010,
reports no knowledge of subsistence activities in Berners Bay during
this time (Coeur Alaska, Inc., 2026).
The proposed project is not expected to affect subsistence hunting,
as there is none in Berners Bay, which includes the project area.
Further, the work would be temporary (33 days) and localized to a
specific area, and construction is taking place outside of the spring
spawning season of eulachon and Pacific herring when subsistence
species are more active (approximately mid-March to mid-May).
Based on the description of the specified activity, the measures
described to minimize adverse effects on the availability of marine
mammals for subsistence purposes, and the proposed mitigation and
monitoring measures, NMFS has preliminarily determined that there will
not be an unmitigable adverse impact on subsistence uses from Coeur'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 ensure 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 in issuing incidental take authorizations, NMFS
consults internally whenever we propose to authorize take of ESA-listed
species, in this case, with the NMFS Alaska Regional Office.
NMFS is proposing to authorize takes of the humpback whale (Mexico-
North Pacific stock (Mexico DPS), ESA-listed as threatened, and the WNP
stock (WNP DPS), ESA-listed as endangered) and the Steller sea lion
(Western stock (Western DPS, ESA-listed as endangered)).
OPR has requested initiation of an ESA section 7 consultation with
the NMFS Alaska Regional Office for the issuance of this IHA. NMFS will
conclude the ESA consultation before reaching a determination on the
proposed authorization issuance.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to Coeur for conducting the in-water pile driving and
removal activities as part of the Kensington Dock Repair Project in
Berners Bay, 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/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>.
Request for Public Comments
We request comments on our analyses, the proposed authorization,
and any other aspect of this notice of proposed IHA for the proposed
Kensington Dock Repair Project. We also request comments 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.
[[Page 23088]]
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 the
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: April 24, 2026.
Shannon Bettridge,
Chief, Marine Mammal and Sea Turtle Conservation Division, Office of
Protected Resources, National Marine Fisheries Service.
[FR Doc. 2026-08299 Filed 4-28-26; 8:45 am]
BILLING CODE 3510-22-P
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