Notice2026-18458
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the PetroMarine Services Juneau Rock Dump Terminal Reconstruction Project, Juneau, Alaska
Primary source
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Published
September 10, 2026
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from PetroMarine Services (PM) for authorization to take marine mammals incidental to the Juneau International Airport (JNU) Rock Dump Fuel Terminal Reconstruction Project in Juneau, 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 take marine mammals incidental to 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.
Full Text
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<title>Federal Register, Volume 91 Issue 174 (Thursday, September 10, 2026)</title>
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[Federal Register Volume 91, Number 174 (Thursday, September 10, 2026)]
[Notices]
[Pages 57550-57575]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-18458]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XF848]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the PetroMarine Services Juneau
Rock Dump Terminal Reconstruction Project, Juneau, 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 PetroMarine Services (PM) for
authorization to take marine mammals incidental to the Juneau
International Airport (JNU) Rock Dump Fuel Terminal Reconstruction
Project in Juneau, 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 take marine
mammals incidental to the specified activities. NMFS is also requesting
comments on a possible one-time, 1-year renewal that could be
[[Page 57551]]
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.
DATES: Comments and information must be received no later than October
13, 2026.
ADDRESSES: Comments should be addressed to 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#4c05181c62293f2f240c22232d2d622b233a"><span class="__cf_email__" data-cfemail="c28b9692eca7b1a1aa82acada3a3eca5adb4">[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: Carter Esch, 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 February 18, 2026, NMFS received a request from PM for an IHA to
take marine mammals incidental to vibratory pile driving and removal
and impact pile driving associated with the JNU Rock Dump Fuel Terminal
reconstruction project in Juneau, AK. Following NMFS' review of the
application, PM submitted a revised version on April 20, June 1, and
July 27, 2026. The application was deemed adequate and complete on
August 28, 2026. PM's request is for take of five species of marine
mammals by Level B harassment, and for a subset (harbor porpoises,
harbor seals, and Steller sea lions (SSLs)), Level A harassment.
Neither PM nor NMFS expect serious injury or mortality to result from
this activity and, therefore, an IHA is appropriate.
Description of Proposed Activity
Overview
PM proposes to replace an existing pile-supported T-dock and fuel
float and construct improvements to the existing fuel line at the JNU
Rock Dump Fuel Terminal Dock on the eastern side of Gastineau Channel
near downtown Juneau, AK. The existing pile-supported T-dock and fuel
float structures were constructed in 1971 and have exceeded the
intended design life for timber structures in a marine environment.
Replacing the existing structures and rerouting fuel lines will allow
Petro Marine to safely and efficiently operate their fuel supply
business.
Activities that have the potential to take marine mammals by Level
A harassment and Level B harassment include vibratory pile removal and
vibratory and impact pile driving. The specified activities would occur
on approximately 81 days over 12 months.
Dates and Duration
The IHA would be effective upon written notification from PM to
NMFS but not beginning later than 1 year from the date of issuance or
extending beyond 2 years from the date of issuance. The specified
activities are currently scheduled to begin January 1, 2027, and would
occur on approximately 81 days (potentially non-consecutive). Pile
removal and installation would occur during daylight hours only, which
ranges from 8 to 18 hours per day in Juneau, AK, depending upon the
season.
Specific Geographic Region
The project is located adjacent to downtown Juneau, AK, on the
eastern shore of Gastineau Channel. Part of Southeast Alaska's Inside
Passage, Gastineau Channel is a U-shaped, glacier-carved, fjord and
narrow channel that, at its approximate midpoint, runs between Juneau
(on mainland Alaska) and Douglas Island. The channel is approximately
16 miles (25.7 kilometers (km)) long and its width varies between 4,000
to 6,000 feet (ft) (1,219 to 1,829 meters (m)). The southern end of
Gastineau Channel meets Stephens Passage, and the northern, shallower
end opens into Auke Bay and Lynn Canal. Gastineau Channel experiences
tidal ranges of 16.3 ft (4.9 m) (NOAA, 2025). There are 12 documented
anadromous fish streams in the vicinity of the project (Alaska
Department of Fish and Game [ADF&G] 2025a); each
[[Page 57552]]
supporting at least one species of Pacific salmon.
The Juneau waterfront is heavily influenced by industrialization,
characterized by a blend of heavy marine industrial activities and
significant tourism infrastructure. The waterfront supports commercial
seafood processing, fishing, and, historically, major mining
operations. The area is frequented by commercial and recreational
vessel traffic, most notably large cruise ships.
BILLING CODE 8011-01-P
[GRAPHIC] [TIFF OMITTED] TN10SE26.000
BILLING CODE 8011-01-C
Detailed Description of the Specified Activity
The JNU Rock Dump Fuel Terminal Reconstruction Project would
include reconstruction of a pile-supported T-dock and fuel float and
improvements to existing fuel lines. In addition to the T-dock, PM
would construct four new dolphins, install a new armor rock revetment
to replace a timber-pile retaining wall, and complete upland
improvements. Demolition of existing infrastructure (i.e., original T-
dock and fuel float structures, tie-back timber retaining wall) would
precede installation of any new projects components.
To complete the project, PM would conduct vibratory pile removal
and impact and vibratory pile driving, performed primarily from a crane
barge and supported as necessary from shore to install and remove a
variety of pile sizes (i.e., 10-16-inch (in), 24-in, 30-in) and types
(i.e., timber or steel). Additional proposed activities include fill
placement using a land-based excavator, and vessel operations (i.e.,
tug and barge), although these activities are not expected to result in
incidental harassment of marine mammals. Both the descriptions below
and table 1 summarize the piling methods, pile size and quantity,
installation timing, and effort of the specified activities.
Removal of Existing Dock and Piles
PM would remove the existing pile-supported fuel dock, fuel float,
mooring and breasting dolphins and timber retaining wall near shore in
their entirety using vibratory methods. PM would remove decking and
float components first, followed by pile extraction; a barge laden with
the demolition waste would be towed to the Seattle area for materials
recycle and disposal within an authorized landfill. NMFS does not
anticipate take from the barge towing waste, and it is not discussed
further.
Dock Replacement
The new main dock will primarily consist of large diameter steel
pipe piles, steel pile caps, timber decking,
[[Page 57553]]
and an energy absorbing fender system. Prefabricated steel catwalks
will be placed between the main fuel dock and two adjacent breasting
dolphins and two mooring dolphins to provide pedestrian access for
tending vessel mooring lines. A pile-supported approach dock of similar
design will extend from shore to the main dock. The approach dock will
be connected to shore by a pile-supported concrete abutment. It is
anticipated that fuel lines will be rerouted from shore and run
alongside the approach dock to a header cabinet on the main dock. A 4-
ton hydraulic crane with an approximate 35-ft (10.7 m) reach will be
located near the dock face, and fendering will be provided around the
perimeter of the main dock.
PM would install temporary steel piles and template piles using a
vibratory hammer to ensure proper positioning of the permanent piles.
Permanent piles will be initially installed with vibratory pile driving
equipment and then proofed for proper penetration and load capacity
with an impact pile driver. Steel pile caps will be field welded to the
tops of piles to support timber superstructure and decking.
Prefabricated steel catwalks will be placed between the main fuel dock
and adjacent breasting and mooring dolphins to provide pedestrian
access for tending vessel mooring lines.
Pile quantities and installation methods are summarized in table 1.
Other Activities
Using an excavator along the top of the existing waterfront
embankment slope, PM would remove existing embankment fill, which is
undersized and prone to coastal erosion, and install approximately
2,200 cubic yards (CY) (1,682 cubic meters (m\3\)) of armor rock in a
layer 4-ft (1.2 m) in depth to mitigate slope erosion and surficial
instability caused by wave and wake activity. The armor rock will
stabilize the existing embankment slope between the new fuel dock and
shore. Excavation and fill are not expected to result in take of marine
mammals, and these activities are not discussed further.
Table 1--PM's Proposed Construction Activities
----------------------------------------------------------------------------------------------------------------
Project total Days of
Structure and pile parameters Installation number of Max piles Average piles effort
method \1\ piles per day per day \2\
----------------------------------------------------------------------------------------------------------------
Pile Removal
----------------------------------------------------------------------------------------------------------------
Retaining Wall and Approach Dock (10''- V 50 12 10 6
16'' Timber Piles)......................
Main Dock and Fuel Float (10''-16'' V 124 12 8 16
Timber Piles)...........................
Breasting Dolphin (10''-16'' Timber V 28 10 8 4
Piles)..................................
Mooring Dolphin (24'' Steel Pipe Piles).. V 4 6 5 1
Mooring Dolphin (30'' Steel Pipe Piles).. V 2 6 5 1
----------------------------------------------------------------------------------------------------------------
Temporary Piles
----------------------------------------------------------------------------------------------------------------
Template (24'' Steel Pipe Piles)......... V 48 12 8 6
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New Pile Installation
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Mooring and Breasting Dolphins (30'' V 14 2 1 14
Steel Pipe Piles)....................... I
Approach and Main Dock (24'' Steel Pipe V 23 2 1 23
Piles).................................. I
Abutment (24'' Steel Pipe Piles)......... V 4 4 3 2
I
Fender Piles (16'' Steel Pipe Piles)..... V 12 6 5 3
I
Fender Piles (24'' Steel Pipe Piles)..... V 4 5 4 2
I
Fuel Line Support Piles (16''Steel Pipe V 12 6 4 3
Piles).................................. I
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\1\ Installation methods include vibratory pile driving (V) and impact pile driving (I).
\2\ The number of construction days was calculated assuming average piles/day rate.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all this information, and we refer the reader to these
descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 2 lists all species or stocks for which take is 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) and potential biological
removal (PBR), where known. PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, which may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no serious injury or mortality is anticipated or proposed
to be authorized here, PBR and annual mortality and serious injury (M/
SI) from anthropogenic sources are
[[Page 57554]]
included here as gross indicators of the status of the species or
stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' Alaska Marine Mammal Stock Assessments (e.g., Young et al.,
2025). All values presented in table 2 are the most recently available
at the time of publication and are available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
Table 2--Species,\1\ Stocks, and the Status of Marine Mammals With Estimated Take From the Specified Activities
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Total
ESA/ MMPA status; Stock abundance (CV, Potential annual
Common name Scientific name Stock strategic (yes/ Nmin, most recent biological mortality/
no) \2\ abundance survey) \3\ removal serious
injury \4\
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Order Artiodactyla--Infraorder Cetacea--Mysticeti (Baleen Whales)
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Family Balaenopteridae:
Humpback Whale.................. Megaptera novaeangliae. Hawai'i............... -, -, N 11,278 (0.56, 7,265, 127 27.09
2020).
Mexico-North Pacific.. T, D, Y NA (NA, NA, 2006) \4\. UND 0.57
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Odontoceti (Toothed Whales, Dolphins, and Porpoises)
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Family Delphinidae (Dolphins):
Killer Whale.................... Orcinus orca........... Eastern North Pacific -, -, N 1,920 (NA, 1,920, 19 1.3
Alaska Resident. 2019).
Eastern North Pacific -, -, N 587 (NA, 587, 2012)... 5.9 0.8
Gulf of Alaska,
Aleutian Islands, and
Bering Sea Transient.
Eastern Northern -, -, N 302 (NA, 302, 2018)... 2.2 0.2
Pacific Northern
Resident.
West Coast Transient.. -, -, N 349 (NA, 349, 2018)... 3.5 0.4
Family Phocoenidae (Porpoises):
Harbor Porpoise................. Phocoena phocoena...... Northern Southeast -, -, N 1,619 (0.26, 1,250, 13 5.6
Alaska Inland Waters. 2019).
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Order Carnivora--Pinnipedia (Seals and Sea Lions)
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Family Otariidae (Eared Seals and
Sea Lions):
Steller Sea Lion................ Eumetopias jubatus..... Western............... E, D, Y 49,837 (NA, 49,837, 299 267
2022).
Eastern............... -, -, N 36,308 (NA, 36,308, 2,178 93.2
2022).
Family Phocidae (Earless Seals):
Harbor Seal..................... Phoca vitulina......... Lynn Canal/Stephens -, -, N 13,388 (NA, 11,867, 214 50
Passage. 2016).
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\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>).
\2\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or
which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is
automatically designated under the MMPA as depleted and as a strategic stock.
\3\ NMFS marine mammal SARs online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports</a>. CV is
the coefficient of variation; Nmin is the minimum estimate of stock abundance. NA is not available or applicable. UND is undetermined.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, vessel strike, Native subsistence mortality). Annual Mortality/Serious Injury often cannot be determined precisely and is in
some cases presented as a minimum value or range.
As indicated above, table 2 lists the five species (10 total
stocks) that temporally and spatially co-occur with the specified
activities to the degree that incidental take is likely to occur. All
species that could potentially occur in the proposed survey areas are
included in table 3 of the IHA application.
While gray whales (Eschrichtius robustus), minke whales (Balaena
acutorostrata), sperm whales (Physeter macrocephalus), Dall's porpoise
(Phocoenoides dalli), and Pacific white-sided dolphins (Lagenorhynchus
obliquidens) have been documented in the area, the temporal and/or
spatial occurrence of these species is such that take is not expected
to occur, and they are not discussed further. Take of these species has
not been requested nor proposed to be authorized, and these species are
not considered further in this document. In addition, the northern sea
otter (Enhydra lutris kenyoni) can be found in Southeast Alaska;
however, this species is managed by the U.S. Fish and Wildlife Service
and is not considered further in this document.
Humpback Whales
Humpback whales migrate to Southeast Alaska in spring to feed after
months of fasting in equatorial breeding grounds in Hawaii and Mexico,
although they have been observed in Southeast Alaska year-round (Baker
et al., 1986). Individuals found in the project area are predominantly
members of the Hawaii distinct population segment (DPS) (98 percent
probability in Southeast Alaska); however, based on a comprehensive
photoidentification study, members of the Mexico DPS have a small
potential to occur in the project location (2 percent probability in
Southeast Alaska) (Wade, 2021).
Peak abundance of humpback whales in Southeast Alaska typically
occurs during late summer to early fall. Most humpback whales begin
returning to southern breeding grounds in fall or winter. However, due
to temporal overlap between whales departing and returning, humpbacks
can be found in
[[Page 57555]]
Alaskan feeding grounds in every month of the year (Baker et al., 1985;
Straley, 1990; Wynne and Witteveen, 2009). Over-wintering (non-
breeding) individuals may be skipping migration altogether in response
to the availability of winter schools of fish, such as herring
(Straley, 1990; Straley et al., 2018)). Large portions of Southeast
Alaska have been identified as humpback whale biologically important
areas (BIAs) for seasonal feeding due to the species' dependence on
foraging resources in the region. The BIAs are active from April
through October to overlap with the highest densities of humpback
whales and their prey (Wild et al., 2023). Although not included in the
BIA, the narrow Gastineau Channel is positioned between two known
humpback whale foraging areas, Lynn Canal to the north and Stephens
Passage to the south. In Stephens Passage, humpback whales are most
often observed during seasons of high prey concentration, May through
September (Witteveen et al., 2011); however, feeding humpback whales'
presence in the Gulf of Alaska has also been correlated closely with
peak abundance of Pacific herring (Clupea pallasii) during late fall
and early winter. Therefore, humpbacks may be present year-round in
southeast Alaska but are less common during the late winter and early
spring. The project area is not located in or near designated critical
habitat.
Killer Whales
Killer whales occur along the entire Alaska coast, in British
Columbia and Washington inland waterways, and along the outer coasts of
Washington, Oregon, and California. In Southeast Alaska, two resident
ecotypes (Alaska Resident and Northern Resident) range from the
Aleutian Islands to Washington State and two transient populations
(West Coast Transient and Gulf of Alaska, Aleutian Islands and Bering
Sea Transient) are found from California to Southeast Alaska (Young et
al., 2026; Myers et al., 2021). Limited information is available
regarding the occurrence of different stocks within the project area.
Based on photograph identification from 2012 through 2016, Luck (2017)
estimated that 55 percent of the population in the Juneau area is from
resident stocks and 43 percent is from transient stocks; however,
citizen science sources, including Happy Whale and local experts, have
primarily observed the transient ecotype in the vicinity of the
project.
Harbor Porpoises
In southeast Alaska, harbor porpoises from the Northern Southeast
Alaska Inland Waters stock utilize coastal waters from Cape Suckling to
the Canada border (Dalheim et al., 2009; Muto et al., 2022). While
harbor porpoises occur most frequently in water depths less than 100 m
(Hobbs and Waite, 2010), they have been documented foraging in waters
up to 200 m deep feeding on small pelagic schooling fish such as
herring and cod (Bj[oslash]rge and Tolley 2009; Wynne et al., 2011).
Calving generally occurs from May to August but can vary by region.
Little else is known about harbor porpoises in southeast Alaska,
including the project area, prompting the ADF&G in 2024 to begin
collecting data through multi-year aerial and vessel-based surveys to
elucidate harbor porpoise numbers, habitat use, and patterns in genetic
relatedness. Although harbor porpoises are common in coastal areas of
Southeast Alaska's Inside Passage, sightings in Gastineau Channel are
relatively rare.
Steller Sea Lions
The majority of Steller sea lions (SSLs) that inhabit Southeast
Alaska are part of the Eastern DPS; however, branded individuals from
the Western DPS make regular movements across the 144[deg] longitude
boundary to the northern ``mixing zone'' haulouts and rookeries within
Southeast Alaska (Jemison et al., 2013). While haulouts and rookeries
in the northern portion of Southeast Alaska may be important areas for
Western DPS animals, there continues to be little evidence that their
regular range extends to the southern haulouts and rookeries in
Southeast Alaska (Jemison et al., 2018). However, genetic data analyzed
in Hastings et al. (2020) indicated that up to 1.4 percent of Steller
sea lions near the project area may be members of the Western DPS,
which NMFS recommends using in their 2020 guidance (Hastings et al.,
2020; NMFS, 2020). There are several haulouts in Southeast Alaska but
none in Gastineau Channel; the nearest haulout, Benjamin Island, is
approximately 45 km (28 mi) from the JNU Rock Dump Fuel Terminal.
Harbor Seals
Harbor seals occur year-round in the inside passages of Southeast
Alaska and are regularly sighted in Gastineau Channel. Harbor seals
forage on fish and invertebrates (Orr et al., 2004), including capelin,
eulachon, cod, pollock, flatfish, shrimp, octopus, and squid (Wynne,
2012). They are opportunistic feeders that forage in marine, estuarine,
and occasionally freshwater habitat, adjusting their foraging behavior
to take advantage of prey that are locally and seasonally abundant
(Payne and Selzer, 1989). Research has demonstrated that harbor seals
conduct both shallow and deep dives while foraging (Tollit et al.,
1997), depending on prey availability.
Harbor seals use a variety of terrestrial sites to haul out for
resting (year-round), pupping (May-July), and molting (August-
September) including tidal and intertidal reefs, beaches, sand bars,
and glacial/sea ice. Some sites have traditional/historic value for
pupping and molting while others are used as temporary resting sites
during seasonal foraging trips. Harbor seals usually give birth to a
single pup between May and mid-July; birthing locations are dispersed
over several haulout sites and not confined to major rookeries
(Klinkhart et al., 2008). They are nonmigratory; their local movements
are associated with tides, weather, season, food availability, and
reproduction, as well as sex and age class (Swain et al., 1996; Lowry
et al., 2001; Boveng et al., 2012). Up to 44 percent of their time is
spent hauled out, with hauling out occurring more often during the
summer (Pitcher and Calkins 1979; Kinkhart et al. 2008). Harbor seals
typically haul out in groups of 30 or less but have been known to
rarely haul out in numbers of several hundred. There are no key haulout
locations defined for harbor seals in the project area, but harbor
seals are known to haul out on the shoals near the DIPAC hatchery
northwest of the project (Alaska Fisheries Science Center [AFSC] 2025);
thus, moderate numbers of seals can be expected to move up Gastineau
Channel through the project area toward this haulout, particularly
during hatchery releases.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
(2007; 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). Generalized hearing ranges were
chosen based on the approximately 65 decibel (dB) threshold from
composite audiograms, previous
[[Page 57556]]
analyses in NMFS (2018), and/or data from Southall et al. (2007) and
Southall et al. (2019). We note that the names of two hearing groups
and the generalized hearing ranges of all marine mammal hearing groups
have been recently updated (NMFS, 2024) as reflected below in table 3.
Table 3--Marine Mammal Hearing Groups
[NMFS, 2024]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 36 kHz.
whales).
High-frequency (HF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
Very High-frequency (VHF) cetaceans 200 Hz to 165 kHz.
(true porpoises, Kogia, river
dolphins, Cephalorhynchid,
Lagenorhynchus cruciger & L.
australis).
Phocid pinnipeds (PW) (underwater) 40 Hz to 90 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 68 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
*Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges may not be as broad. Generalized hearing range
chosen based on 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 are
able to detect very loud sounds above and below that ``generalized''
hearing range.
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2024) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section discusses how components of the specified activity may
impact marine mammals and their habitat. The Estimated Take of Marine
Mammals section later in this document includes a quantitative analysis
of the number of individuals that are expected to be taken by this
activity. The Negligible Impact Analysis and Determination section
considers the content of this section, the Estimated Take of Marine
Mammals section, and the Proposed Mitigation section to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and whether those
impacts are reasonably expected to, or reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.
Acoustic effects on marine mammals during the specified activities
are likely to result from impact pile installation and vibratory pile
installation and removal. The effects of underwater noise generated by
PM's proposed activities have the potential to result in Level B
harassment of marine mammals in the action area and, for some species/
stocks as a result of certain proposed activities, Level A harassment.
There are a variety of types and degrees of effects to marine
mammals, prey species, and habitat that could occur as a result of the
proposed activities. Below we provide a brief description of the types
of sound sources that would be generated by the project, the general
impacts from these types of activities, and an analysis of the
anticipated impacts on marine mammals from the project, with
consideration of the proposed mitigation measures.
Description of Sound Sources
Activities associated with the PM project that have the potential
to incidentally take marine mammals through sound exposure include
vibratory removal of timber piles, vibratory installation of steel
piles, and impact installation of steel piles. Impact hammers typically
operate by repeatedly dropping and/or pushing a heavy piston onto a
pile to drive the pile into 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 weight of the hammer to push them into substrate. Vibratory hammers
typically produce less sound (i.e., lower levels) than impact hammers.
Peak sound pressure levels (SPL<INF>pk</INF>) may be 180 dB or greater
but are generally 10-20 dB lower than SPLs generated during impact pile
driving of the same-sized pile (Oestman et al., 2009; California
Department of Transportation, 2020). Sounds produced by vibratory
hammers are non-impulsive; compared to sounds produced by impact
hammers, the rise time is slower, reducing the probability and severity
of injury, and the sound energy is distributed over a greater amount of
time (Nedwell and Edwards, 2002; Carlson et al., 2005).
The likely or possible impacts of PM'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 consistent or dedicated pinniped haulouts within the immediate
vicinity of any of the six project sites, we have determined that
visual and other nonacoustic stressors would be limited, and any
impacts on marine mammals are primarily expected to be acoustic in
nature.
Potential Effects of Underwater Sound on Marine Mammals
The introduction of anthropogenic noise into the aquatic
environment from vibratory and impact pile driving are the means by
which marine mammals may be harassed from PM's specified activities.
Anthropogenic sounds span a broad range of frequencies and sound levels
and can have highly variable impacts on marine life, 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 these projects,
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, 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 impact/vibratory hammers is reasonably likely to result
in such effects. 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
[[Page 57557]]
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.
Regarding non-acoustic effects, while harbor seals and Steller sea
lions are known to haul out in southeast Alaska, there are no rookeries
or known dedicated haulouts for either of these species in the
immediate vicinity of the project areas (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.
In general, animals exposed to natural or anthropogenic sound may
experience physical and psychological effects, ranging in magnitude
from none to severe (Southall et al., 2007, 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 acoustic effects that may result
incidental to PM's proposed activities.
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 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 potential impacts on
marine mammals and their habitats from noise in general, starting with
hearing impairment, as well as from the specific activities PM plans to
conduct, to the extent 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).
Auditory Injury (AUD INJ)
NMFS (2024) defines AUD INJ as damage to the inner ear that can
result in destruction of tissue, such as the 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 does not generally affect more than a limited
frequency range, and an animal that has incurred PTS has some level of
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 AUD INJ
onset (see Ward et al., 1958, 1959; Ward, 1960; Kryter et al., 1966;
Miller, 1974; Ahroon et al., 1996; Henderson et al., 2008). AUD INJ
levels for marine mammals are estimates, as with the exception of a
single study unintentionally inducing PTS in a harbor seal (Kastak et
al., 2008), there are no empirical data measuring AUD INJ 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).
Temporary Threshold Shift (TTS)
TTS is a temporary, reversible increase in the threshold of
audibility at a specified frequency or portion of an individual's
hearing range above a previously established reference level (NMFS,
2024), and is not considered an 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 in Finneran (2015), marine mammal studies have shown 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 exposures with higher
SEL<INF>24</INF>, the growth curves become steeper and approach linear
relationships with the sound exposure level (SEL).
[[Page 57558]]
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 be able to
readily compensate for a brief, relatively small amount of TTS in a
non-critical frequency range that takes place during a time when the
animal is traveling through the open ocean, where ambient noise is
lower and there are not as many competing sounds present.
Alternatively, a larger amount and longer duration of TTS sustained
during time when communication is critical for successful mother/calf
interactions could have more severe impacts. We note that reduced
hearing sensitivity as a simple function of aging has been observed in
marine mammals, as well as humans and other taxa (Southall et al.,
2007), so we can infer that strategies exist for coping with this
condition to some degree, though likely not without cost.
Many studies have examined noise-induced hearing loss in marine
mammals (see Finneran (2015) and Southall et al. (2019) for summaries).
TTS is the mildest form of hearing impairment that can occur during
exposure to sound. While experiencing TTS, the hearing threshold rises,
and a sound must be at a higher level in order to be heard. In
terrestrial and marine mammals, TTS can last from minutes or hours to
days (in cases of strong TTS). In many cases, hearing sensitivity
recovers rapidly after exposure to the sound ends. For cetaceans,
published data on the onset of TTS are limited to captive bottlenose
dolphin (Tursiops truncatus), beluga whale (Delphinapterus leucas),
harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis) (Southall et al., 2019). For pinnipeds in water,
measurements of TTS are limited to harbor seals, elephant seals
(Mirounga angustirostris), bearded seals (Erignathus barbatus), and
California sea lions (Kastak et al., 2007; Kastelein et al., 2019b,
2019c, 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 measured in marine mammals before
and after exposure to intense or long-duration sound exposures. The
difference between the pre-exposure and post-exposure thresholds can be
used to determine the amount of threshold shift at various post-
exposure times.
The amount and onset of TTS depends on the exposure frequency.
Sounds 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
will be less than the TTS from a single, continuous exposure with the
same SEL (Mooney et al., 2009; Finneran et al., 2010; Kastelein et al.,
2014, 2015). This means that TTS predictions based on the total
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 relatively loud sound
was preceded by a warning sound. These captive animals were shown to
reduce hearing sensitivity when warned of an impending intense sound.
Based on these experimental observations of captive animals, the
authors suggest that wild animals may dampen their hearing during
prolonged exposures or if conditioned to anticipate intense sounds.
Another study showed that echolocating animals (including odontocetes)
might have anatomical specializations that might allow for conditioned
hearing reduction and filtering of low-frequency ambient noise,
including increased stiffness and control of middle ear structures and
placement of inner ear structures (Ketten et al., 2021). Data available
on noise-induced hearing loss for mysticetes are currently lacking
(NMFS, 2024). Additionally, the existing marine mammal TTS data come
from a limited 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.
Behavioral Effects
Exposure to noise also has the potential to behaviorally disturb
marine mammals response--in other words, not every response qualifies
as behavioral disturbance, and for responses that do, those of a higher
level, or accrued across a longer duration, have the potential to
affect foraging, reproduction, or survival. Behavioral disturbance may
include a variety of effects, including subtle changes in behavior
(e.g., minor or brief avoidance of an area or changes in
vocalizations), more conspicuous changes in similar behavioral
activities, and more sustained and/or potentially severe reactions,
such as displacement from or abandonment of high-quality habitat.
Behavioral responses may include changing durations of surfacing and
dives, changing direction and/or speed; reducing/increasing vocal
activities; changing/cessation of certain behavioral activities (such
as socializing or feeding); eliciting a visible startle response or
aggressive behavior (such as tail/fin slapping or jaw clapping); and
avoidance of 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., 2003; Southall et al., 2007, 2019; Weilgart, 2007;
Archer et al., 2010).
[[Page 57559]]
Behavioral reactions can vary not only among individuals but also
within an individual, depending on previous experience with a sound
source, context, and numerous other factors (Ellison et al., 2012), and
can vary depending on characteristics associated with the sound source
(e.g., whether it is moving or stationary, number of sources, distance
from the source). In general, pinnipeds seem more tolerant of, or at
least habituate more quickly to, potentially disturbing underwater
sound than do cetaceans, and generally seem to be less responsive to
exposure to industrial sound than most cetaceans. Please see appendices
B and C of Southall et al. (2007) and Gomez et al. (2016) for reviews
of studies involving marine mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2003). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure.
As noted above, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; Wartzok et al., 2003; 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). Observed responses of wild marine
mammals to loud-pulsed sound sources (e.g., seismic airguns) have been
varied but often consist of avoidance behavior or other behavioral
changes (Richardson et al., 1995; Morton and Symonds, 2002; Nowacek et
al., 2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal (e.g., Erbe et al., 2019). If a marine mammal does react
briefly to an underwater sound by changing its behavior or moving a
small distance, the impacts of the change are unlikely to be
significant to the individual, let alone the stock or population. If a
sound source displaces marine mammals from an important feeding or
breeding area for a prolonged period, impacts on individuals and
populations could be significant (e.g., Lusseau and Bejder, 2007;
Weilgart, 2007; NRC, 2005). However, there are broad categories of
potential response, which we describe in greater detail here, that
include alteration of dive behavior, alteration of foraging behavior,
effects to breathing, interference with or alteration of vocalization,
avoidance, and flight.
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). Variations in dive behavior
may reflect interruptions in biologically significant activities (e.g.,
foraging) or they may be of little biological significance. The impact
of an alteration to dive behavior resulting from an acoustic exposure
depends on what the animal is doing at the time of the exposure and the
type and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. Acoustic and movement bio-logging tools also have been used
in some cases to infer responses to anthropogenic noise. For example,
Blair et al. (2016) reported significant effects on humpback whale
foraging behavior in Stellwagen Bank in response to ship noise
including slower descent rates, and fewer side-rolling events per dive
with increasing ship nose. In addition, Wisniewska et al. (2018)
reported that tagged harbor porpoises demonstrated fewer prey capture
attempts when encountering occasional high-noise levels resulting from
vessel noise as well as more vigorous fluking, interrupted foraging,
and cessation of echolocation signals observed in response to some
high-noise vessel passes. As for other types of behavioral response,
the frequency, duration, and temporal pattern of signal presentation,
as well as differences in species sensitivity, are likely contributing
factors to differences in response in any given circumstance (e.g.,
Croll et al., 2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko
et al., 2007). A determination of whether foraging disruptions incur
fitness consequences would require information on or estimates of the
energetic requirements of the affected individuals and the relationship
between prey availability, foraging effort and success, and the life
history stage of the animal.
Respiration rates vary naturally with different behaviors and
alterations to breathing rate as a function of acoustic exposure can be
expected to co-occur with other behavioral reactions, such as a flight
response or an alteration in diving. However, respiration rates in and
of themselves may be representative of annoyance or an acute stress
response. Various studies have shown that respiration rates may either
be unaffected or could increase, depending on the species and signal
characteristics, again highlighting the importance in understanding
species differences in the tolerance of underwater noise when
determining the potential for impacts resulting from anthropogenic
sound exposure (e.g., Kastelein et al., 2001; 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 referenced to 1 microPascal ([mu]Pa) (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 as a result of the presence of a sound or other
stressors and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). Harbor porpoises, Atlantic
white-sided dolphins (Lagenorhynchus actusus), and minke whales have
demonstrated avoidance in response to vessels during line transect
surveys (Palka and Hammond, 2001). In addition, beluga whales in the
St. Lawrence Estuary in Canada have been reported to increase levels of
avoidance with increased boat presence by way of increased dive
durations and swim speeds, decreased surfacing intervals, and by
bunching together into groups (Blane and Jaakson, 1994). Avoidance may
be short-term, with animals returning to the area once the noise has
ceased (e.g., Bowles et al., 1994; Morton and Symonds, 2002; Gailey et
al., 2007). Longer-term displacement is possible, however, which may
lead to changes in abundance or distribution patterns of the affected
species in the affected region if habituation to the presence of the
sound does not occur (e.g.,
[[Page 57560]]
Blackwell et al., 2004; Bejder et al., 2006; Teilmann et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996; Bowers et al., 2018). The result of a flight response
could range from brief, temporary exertion and displacement from the
area where the signal provokes flight to, in extreme cases, marine
mammal stranding. However, it should be noted that response to a
perceived predator does not necessarily invoke flight (Ford and Reeves,
2008), and whether individuals are solitary or in groups may influence
the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fishes and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Daan et
al., 1996; Bradshaw et al., 1998). However, Ridgway et al. (2006)
reported that increased vigilance in bottlenose dolphins exposed to
sound over a 5-day period did not cause any sleep deprivation or stress
effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than 1 day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive (i.e., meaningful) behavioral reactions and multi-day
anthropogenic activities. For example, just because an activity lasts
for multiple days does not necessarily mean that individual animals are
either exposed to activity-related stressors for multiple days or,
further, exposed in a manner resulting in sustained multi-day
substantive behavioral responses.
Physiological Stress Responses
An animal's perception of a threat may be sufficient to trigger
stress responses consisting of some combination of behavioral
responses, autonomic nervous system responses, neuroendocrine
responses, or immune responses (e.g., Selye, 1950; Moberg, 2000). In
many cases, an animal's first and sometimes most economical (in terms
of energetic costs) response is behavioral avoidance of the potential
stressor. Autonomic nervous system responses to stress typically
involve changes in heart rate, blood pressure, and gastrointestinal
activity. These responses have a relatively short duration and may or
may not have a significant long-term effect on an animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005; Ayres et al., 2012; Yang
et al., 2021). Stress responses due to exposure to anthropogenic sounds
or other stressors and their effects on marine mammals have also been
reviewed (Fair and Becker, 2000; Romano et al., 2002b) and, more
rarely, studied in wild populations (e.g., Romano et al., 2002a). For
example, Rolland et al. (2012) found that noise reduction from reduced
ship traffic in the Bay of Fundy was associated with decreased stress
in North Atlantic right whales (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. (2021) 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 will experience
physiological stress responses upon exposure to acoustic stressors and
that it is possible that some of these would be classified as
``distress.'' In addition, any animal experiencing TTS would likely
also experience stress responses (NRC, 2005), however distress is an
unlikely result of this 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 particular frequencies for
marine mammals that utilize sound for vital biological functions (Clark
et al., 2009). Acoustic masking is when other noises such as from human
sources interfere with an animal's ability to detect, recognize, or
discriminate between acoustic signals of interest (e.g., those used for
intraspecific communication and social interactions, prey detection,
predator avoidance,
[[Page 57561]]
navigation) (Richardson et al., 1995; Erbe et al., 2016). Therefore,
under certain circumstances, marine mammals whose acoustical sensors or
environments are being severely masked could also be impaired from
maximizing their performance fitness in survival and reproduction. The
ability of a noise source to mask biologically important sounds depends
on the characteristics of both the noise source and the signal of
interest (e.g., signal-to-noise ratio, temporal variability,
direction), in relation to each other and to an animal's hearing
abilities (e.g., sensitivity, frequency range, critical ratios,
frequency discrimination, directional discrimination, age or TTS
hearing loss), and existing ambient noise and propagation conditions
(Hotchkin and Parks, 2013).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation, click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003) or vocalizations (Foote et al., 2004),
respectively, while North Atlantic right whales 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 (Balaenoptera physalus) have also been
documented lowering the bandwidth, peak frequency, and center frequency
of their vocalizations under increased levels of background noise from
large vessels (Castellote et al., 2012). Other alterations to
communication signals have also been observed. For example, gray
whales, in response to playback experiments exposing them to vessel
noise, have been observed increasing their vocalization rate and
producing louder signals at times of increased outboard engine noise
(Dahlheim and Castellote, 2016). Alternatively, in some cases, animals
may cease sound production during production of aversive signals
(Bowles et al., 1994, Wisniewska et al., 2018).
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is anthropogenic, it may be considered
harassment when disrupting or altering critical behaviors. It is
important to distinguish TTS and PTS, which persist after the sound
exposure, from masking, which occurs during the sound exposure. Because
masking (without resulting in TS) is not associated with abnormal
physiological function, it is not considered a physiological effect,
but rather a potential behavioral effect (though not necessarily one
that would be associated with harassment).
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al., 2000;
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2010; Holt
et al., 2009). Masking can be reduced in situations where the signal
and noise come from different directions (Richardson et al., 1995),
through amplitude modulation of the signal, or through other
compensatory behaviors, including modifications of the acoustic
properties of the signal 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. There are few studies addressing
real-world masking sounds likely to be experienced by marine mammals in
the wild (e.g., Branstetter et al., 2013).
Masking occurs in the frequency band that the animals utilize and
is more likely to occur in the presence of broadband, relatively
continuous noise sources such as vibratory pile driving. The energy
distribution of sound from vibratory pile driving covers a broad
frequency spectrum and is anticipated to be within the audible range of
marine mammals present in the proposed action area. Since noises
generated from the proposed construction activities are mostly
concentrated at low frequencies (<2 kilohertz (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 affect 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 frequency band for noise and thus reduce the communication
space of animals (e.g., Clark et al., 2009) and cause increased stress
levels (e.g., Holt et al., 2009). Unlike TS, masking, which can occur
over large temporal and spatial scales, can potentially affect the
species at population, community, or even ecosystem levels, in addition
to individual levels. Masking affects both senders and receivers of the
signals, and at higher levels for longer durations, could have long-
term chronic effects on marine mammal species and populations. However,
the noise generated by PM's proposed activities will only occur
intermittently, across an estimated total of 81 (not necessarily
consecutive) days during the 1-year authorization period covered by
each IHA, if finalized, in a relatively small area focused around the
proposed construction site. Thus, PM's proposed activities may mask
some acoustic signals that are relevant to the daily behavior of marine
mammals, the short-term duration and limited areas affected make it
very unlikely that the fitness of individual marine mammals would be
impacted.
Airborne Acoustic Effects
Pinnipeds that occur near the project site could be exposed to
airborne sounds associated with construction activities that have the
potential to cause behavioral harassment, depending on their distance
from these activities. Airborne noise would primarily be an issue for
pinnipeds that are swimming or hauled out near the project site within
the range of noise levels elevated above airborne acoustic harassment
criteria. Although pinnipeds are known to haul out regularly on man-
made objects, we believe that incidents of take resulting solely from
airborne sound are unlikely due to the proximity between the proposed
project area and the known haulouts (e.g., 3.7 km and 8.6 km away for
harbor seals; 61 km for Steller sea lions). 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 could be exposed to
airborne sound that may result in behavioral harassment when looking
with their heads above water. Most likely, airborne sound would cause
behavioral responses similar to those discussed above in relation to
underwater sound.
[[Page 57562]]
For instance, anthropogenic sound could cause hauled out pinnipeds to
exhibit changes in their normal behavior, such as reduction in
vocalizations, or cause them to 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 the behavioral harassment thresholds, which are
in all cases larger than those associated with airborne sound. Thus,
the behavioral harassment of these animals is already accounted for in
these estimates of potential take. Therefore, we do not believe that
authorization of incidental take resulting from airborne sound for
pinnipeds is warranted, and airborne sound is not discussed further.
Potential Effects on Marine Mammal Habitat
PM's proposed activities could have localized, temporary impacts on
marine mammal habitat, including prey, by increasing in-water SPLs.
Increased noise levels may affect the acoustic habitat (refer to
masking discussion) and adversely affect marine mammal prey in the
vicinity of near the project areas (see discussion below). During
impact and vibratory pile driving or removal, elevated underwater noise
levels would ensonify the project areas where both fish and mammals
occur and could affect foraging success. Additionally, marine mammals
may avoid the area during the proposed construction activities;
however, displacement due to noise is expected to be temporary and is
not expected to result in long-term effects on the individuals or
populations.
In-Water Construction Effects on Potential Foraging Habitat
As previously mentioned, the project area does not contain habitat
of known importance, although it is located near an identified feeding
BIA for humpback whales in Southeast Alaska, active from May through
September (Wild et al., 2023). However, the area only represents a tiny
segment of foraging habitat for humpback whales. No critical habitat is
located within the project area, and the project area is highly
influenced by pre-existing and ongoing anthropogenic development and
activities.
The total seafloor area likely to be impacted by PM's activities is
relatively small compared to the vast foraging area available habitat
in Southeast Alaska. At best, the impact area provides marginal
foraging habitat for marine mammals and fish. Furthermore, proposed
pile driving at the project site would not be expected to obstruct the
movement or migration of marine mammals.
A temporary and localized increase in turbidity near the seafloor
would occur in the immediate area due to the area where piles are
installed or removed. In general, turbidity associated with pile
installation is localized to about a 7.6-m radius around the pile. The
sediments of the project site would settle out rapidly when disturbed.
Cetaceans are not expected to be close enough to the pile-driving areas
to experience the effects of turbidity, and any pinnipeds could avoid
localized turbid areas. Depending on the tidal stage, local strong
currents are anticipated to disburse any additional suspended sediments
produced by project activities at moderate to rapid rates. Therefore,
we expect the impact from increased noise is turbidity levels to be
discountable to marine mammals and do not discuss it further.
The potential for prey (i.e., fish) to temporarily avoid the
immediate area also exists. The duration of fish and marine mammal
avoidance of this area after pile driving stops is unknown, but a rapid
return to normal recruitment, distribution, and behavior is
anticipated. Any behavioral avoidance of the disturbed area by fish or
marine mammals would still leave significantly large areas of fish and
marine mammal foraging habitat in the nearby vicinity.
The proposed project will occur within the same footprint as
existing marine infrastructure. The near-shore and intertidal habitat
where the proposed project will occur is an area of relatively high
marine vessel traffic. Most marine mammals do not generally use the
area within the footprint of the project area. Temporary, intermittent,
and short-term habitat alteration may result from increased noise
levels during the proposed construction activities. Effects on marine
mammals will be limited to temporary displacement from pile
installation and removal noise, and effects on prey species will be
similarly limited in time and space.
Temporary and localized reduction in water quality will occur as a
result of in-water construction activities. Most of this effect would
occur during the installation and removal of piles when seafloor
sediments are disturbed. The installation and removal of piles would
disturb seafloor sediments and may cause a temporary increase in
suspended sediment in the project area. During pile extraction,
sediment attached to the pile moves vertically through the water column
until gravitational forces cause it to slough off under its own weight.
The small resulting sediment plume is expected to settle out of the
water column within a few hours. Studies of the effects of turbid water
on fish (marine mammal prey) suggest that concentrations of suspended
sediment can reach thousands of milligrams per liter before an acute
toxic reaction is expected (Burton, 1993).
Effects to turbidity and sedimentation are expected to be short-
term, minor, and localized. Since there may be strong currents in the
area, following the completion of sediment-disturbing activities,
suspended sediments in the water column should dissipate and quickly
return to background levels in all construction scenarios. Turbidity
within the water column has the potential to reduce the level of oxygen
in the water and irritate the gills of prey fish species in the
proposed project area. However, turbidity plumes associated with the
project would be temporary and localized, and fish in the proposed
project area would be able to move away from and avoid the areas where
plumes may occur. Therefore, it is expected that the impacts on prey
fish 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 Southeast Alaska.
Potential Effects on Prey
Sound may affect marine mammals through impacts on 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, is not well documented.
Studies regarding the effects of noise on known marine mammal prey are
described here.
Fishes utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009).
Depending on their hearing anatomy and peripheral sensory structures,
which vary among species, fishes hear sounds using pressure and
particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage,
[[Page 57563]]
barotrauma (pressure-related injuries), and mortality.
Fish react to sounds that are especially strong and/or intermittent
low-frequency sounds, and behavioral responses such as flight or
avoidance are the most likely effects. Short duration, sharp sounds can
cause overt or subtle changes in fish behavior and local distribution.
The reaction of fish to noise depends on the physiological state of the
fish, past exposures, motivation (e.g., feeding, spawning, migration),
and other environmental factors. Hastings and Popper (2005) identified
several studies that suggest fish may relocate to avoid certain areas
of sound energy. Additional studies have documented effects of pile
driving on 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
loss of auditory function is likely restored when damaged cells are
replaced with new cells. Halvorsen et al. (2012b) showed that a TTS of
4 to 6 dB was recoverable within 24 hours for one species. Impacts
would be most severe when the individual fish is close to the source
and when the duration of exposure is long. Injury caused by barotrauma
can range from slight to severe and can cause death and is most likely
for fish with swim bladders. Barotrauma injuries have been documented
during controlled exposure to impact pile driving (Halvorsen et al.,
2012a; Casper et al., 2013, 2017).
Fish populations in the proposed project area that serve as marine
mammal prey could be temporarily affected by noise from pile
installation and removal. The frequency range in which fishes generally
perceive underwater sounds is 50 to 2,000 Hz, with peak sensitivities
below 800 Hz (Popper and Hastings, 2009). Fish behavior or distribution
may change, especially with strong and/or intermittent sounds that
could harm fishes. High underwater SPLs have been documented to alter
behavior, cause hearing loss, and injure or kill individual fish by
causing serious internal injury (Hastings and Popper, 2005).
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 have indirect effects
on 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 the sound levels from pile driving, seismic
activity, or any human-made sound would have physiological effects on
invertebrates. Any such effects would be limited to the area extremely
near (1 to 5 m) the sound source and would result in no 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 extremely high natural mortality). No
adverse impact on zooplankton populations is expected to occur from the
specified activity due in part to large reproductive capacities and
naturally high levels of predation and mortality of these populations.
Any mortalities or impacts that might occur would be negligible.
The greatest potential impact to marine mammal prey during
construction would occur during impact pile driving. Impact and
vibratory pile driving and removal could possibly elicit behavioral
reactions from fishes such as temporary avoidance of the area but is
unlikely to cause injuries to fishes or have persistent effects on
local fish populations. However, generally, the duration of impact pile
driving would be limited to the final stage of installation
(``proofing'') after the pile has been driven as close as practicable
to the design depth with a vibratory driver (where necessary). In-water
construction activities would only occur during daylight hours,
allowing fish to forage and transit the project area in the evening.
Construction likely would have minimal permanent and temporary
impacts on benthic invertebrate species, a marine mammal prey source.
In addition, it should be noted that the area in question is considered
low-quality habitat since it is already highly developed and
experiences a high level of anthropogenic noise from normal operations
and other vessel traffic.
There are several fish species near Juneau for which NMFS has
identified Essential Fish Habitat (EFH), including: chinook salmon
(Oncorhynchus tshawytscha), chum salmon (O. keta), coho salmon (O.
kisutch), pink salmon (O. gorbuscha), and sockeye salmon (O. nerka) in
fresh and estuarine waters; and staghorn sculpin (Leptocottus armatus),
sablefish (Anoplopoma fimbria), Pacific Ocean perch (Sebastes alutus),
yelloweye rockfish (S. ruberrimus), shortraker rockfish (S. borea),
rougheye rockfish (S. aleutianus), dusky rockfish (S. ciliatus),
Pacific cod, starry flounder (Platichthys stellatus), yellowfin sole
(Pleuronectes asper), and rock sole (P. bilineatus) (Federal Aviation
Administration, 2005). Additionally, there are various other ``forage
fish'' in marine waters located near the project area. These species
may reside in many creeks and water bodies in the area (i.e., Duck
Creek, Jordan Creek, Mendenhall River, Tidal Sloughs, Low Marsh, and
High Marsh) (Federal Aviation Administration, 2005). Given the
temporary nature of activities and the number of additional waterbodies
in the area that present viable habitat, adverse effects on EFH in this
area are not expected.
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 an exceedingly small area compared to the vast foraging area
available to marine mammals outside this project area. Although most of
Southeast Alaska is identified as a BIA for humpback whales (Wild et
al., 2023), the proposed project area is outside of that BIA. It does
not contain particularly high-value habitat and is not known to be of
particular importance to humpback whales or any other species
potentially impacted by PM's activities. The area impacted by the
project is relatively small compared to the available habitat just
outside the project area, and there are no areas of particular
importance that would be impacted by this project. Any behavioral
avoidance by fish of the disturbed area would still leave significantly
large areas of fish and marine mammal foraging habitat in the nearby
vicinity. As described in the preceding, the potential for PM's
[[Page 57564]]
construction to affect the availability of prey to marine mammals or to
meaningfully impact the quality of physical or acoustic habitat is
considered to be insignificant. Therefore, impacts of the project are
not likely to have adverse effects on marine mammal foraging habitat in
the proposed project area.
There are times of known seasonal marine mammal foraging in
Southeast Alaska around fish processing/hatchery infrastructure or when
fish are congregating, but the affected areas of Southeast Alaska are a
small portion of the total foraging habitat available in the region. In
general, effects on marine mammal prey species are expected to be minor
and temporary due to the short timeframe of the project and the small
project footprint.
Increased turbidity from construction activities can adversely
affect forage fish and juvenile salmonid out-migratory routes in the
project area. Both herring and salmon form a significant prey base for
Steller sea lions, whereas herring is the primary prey species of
humpback whales; both herring and salmon are components of the diet of
many other marine mammal species that occur in the project area.
Increased turbidity is expected to occur near construction activities.
However, suspended sediments and particulates are expected to dissipate
quickly within a single tidal cycle. Given the limited area affected
and high tidal dilution rates, any effects on forage fish and salmon
are expected to be minor or negligible. In addition, best management
practices would be in effect, limiting the extent of turbidity to the
immediate project area. Finally, exposure to turbid waters from
construction activities is not expected to differ from the current
exposure; fish of the disturbed area and marine mammals in the
Southeast Alaska region are routinely exposed to substantial levels of
suspended sediment from glacial sources.
In summary, given the temporary nature of the construction project
and relatively small areas being affected, the pile driving
installation and removal activities associated with the proposed action
are not likely to have a permanent, adverse effect on any fish habitat
or populations of fish species. The most likely impact to fishes at the
project site would be temporary avoidance of the area. The most likely
impact on fish from pile driving and removal activities at the project
area would be temporary behavioral avoidance of the area. The duration
of fish avoidance in this area after pile driving stops is unknown, but
a rapid return to regular recruitment, distribution, and behavior is
anticipated. Any behavioral avoidance by fish in 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 to marine mammal
habitat are not expected to result in significant or long-term
consequences for individual marine mammals, or to contribute to the
adverse effects 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).
Takes proposed for authorization would primarily be by Level B
harassment, as use of the acoustic sources (i.e., vibratory and impact
pile driving) has the potential to result in disruption of behavioral
patterns for individual marine mammals. There is also some potential
for auditory injury (AUD INJ) (Level A harassment) to result for harbor
porpoises, Steller sea lions, and harbor seals. The proposed mitigation
and monitoring measures are expected to minimize the severity of the
taking to the extent practicable. As described previously, no serious
injury or mortality is anticipated or proposed to be authorized for
this activity. Below we describe how the proposed take numbers are
estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic criteria above which NMFS believes 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 will be ensonified above these levels in a day; (3) the
density or occurrence of marine mammals within these ensonified areas;
and, (4) the number of days of activities. We note that while these
factors can contribute to a basic calculation to provide an initial
prediction of potential takes, additional information that can
qualitatively inform take estimates is also sometimes available (e.g.,
previous monitoring results or average group size). Below, we describe
the factors considered here in more detail and present the proposed
take estimates.
Acoustic Criteria
NMFS recommends the use of acoustic 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).
Level B Harassment
Though significantly driven by received level, the onset of
behavioral disturbance from anthropogenic noise exposure is also
informed to varying degrees by other factors related to the source or
exposure context (e.g., frequency, predictability, duty cycle, duration
of the exposure, signal-to-noise ratio, distance to the source), the
environment (e.g., bathymetry, other noises in the area, predators in
the area), and the receiving animals (hearing, motivation, experience,
demography, life stage, depth) and can be difficult to predict (e.g.,
Southall et al., 2007, 2021; Ellison et al., 2012). Based on what the
available science indicates and the practical need to use a threshold
based on a metric that is both predictable and measurable for most
activities, NMFS typically uses a generalized acoustic threshold based
on received level to estimate the onset of behavioral harassment. NMFS
generally predicts that marine mammals are likely to be behaviorally
harassed in a manner considered to be Level B harassment when exposed
to underwater anthropogenic noise above root-mean-squared sound
pressure levels (RMS SPL) of 120 dB re 1 [mu]Pa) for continuous (e.g.,
vibratory pile driving) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g.,
scientific sonar) sources. Generally speaking, Level B harassment take
estimates based on these behavioral harassment thresholds are expected
to include any likely takes by TTS as, in most cases, the likelihood of
TTS occurs at distances from the source less than those at which
behavioral harassment is
[[Page 57565]]
likely. TTS of a sufficient degree can manifest as behavioral
harassment, as reduced hearing sensitivity and the potential reduced
opportunities to detect important signals (conspecific communication,
predators, prey) may result in changes in behavior patterns that would
not otherwise occur.
PM's proposed activities include the use of continuous (vibratory
pile driving and removal) and impulsive (impact pile driving) sources,
and therefore the RMS SPL thresholds of 120 and 160 dB re 1 [mu]Pa are
applicable.
Level A Harassment
NMFS' Updated Technical Guidance for Assessing the Effects of
Anthropogenic Sound on Marine Mammal Hearing (Version 3.0) (NOAA, 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). PM's proposed activities
include the use of impulsive (impact pile driving) and non-impulsive
(vibratory pile driving) sources.
The 2024 Updated Technical Guidance criteria include both updated
thresholds and updated weighting functions for each hearing group. The
thresholds are provided in the table below. The references, analysis,
and methodology used in the development of the criteria are described
in NMFS' 2024 Updated Technical Guidance, which may be accessed at:
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools</a>.
Table 4--Thresholds Identifying the Onset of Auditory Injury
----------------------------------------------------------------------------------------------------------------
AUD INJ onset acoustic thresholds * (received level)
-----------------------------------------------------------------------------------------------------------------
Hearing group Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 222 dB; Cell 2: LE,LF,24h: 197 dB.
LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans.......... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,HF,24h: 201 dB.
LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans.... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,VHF,24h: 181 dB.
LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 223 Cell 8: LE,PW,24h: 195 dB.
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 criteria results in the larger isopleth for
calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure
level criteria associated with impulsive sounds, the PK SPL criteria are recommended for consideration for non-
impulsive sources.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa (underwater) and 20 [micro]Pa (in
air), and weighted cumulative sound exposure level (LE,24h) has a reference value of 1 [micro]Pa\2\s
(underwater) and (20 [micro]Pa)\2\s (in air). In this Table, criteria are abbreviated to be more reflective of
International Organization for Standardization standards (ISO 2017; ISO 2020). The subscript ``flat'' is being
included to indicate peak sound pressure are flat weighted or unweighted within the generalized hearing range
of marine mammals underwater (i.e., 7 Hz to 165 kHz) or in air (i.e., 42 Hz to 52 kHz). The subscript
associated with cumulative sound exposure level criteria indicates the designated marine mammal auditory
weighting function (LF, HF, and VHF cetaceans, and PW, OW, PA, and OA pinnipeds) and that the recommended
accumulation period is 24 hours. The weighted cumulative sound exposure level criteria could be exceeded in a
multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it is valuable for
action proponents to indicate the conditions under which these criteria will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the project. Marine
mammals are expected to be affected via sound generated by the primary
components of the project (i.e., vibratory pile removal and
installation, and impact pile driving). The source levels assumed for
both removal and installation activities are based on reviews of
measurements of the same or similar types and dimensions available in
the scientific literature and from similar coastal construction
projects. Source levels for each pile size and activity are presented
in table 5. Source levels for vibratory installation and removal of
piles of the same diameter are assumed to be the same.
Table 5--Proxy Sound Source Levels
----------------------------------------------------------------------------------------------------------------
Source level (at 10 m)
----------------------------------------------------
Pile size and type Peak (dB re 1 RMS (dB re 1 SEL (dB re 1 Reference
[mu]Pa) [mu]Pa) [mu]Pa2 sec)
----------------------------------------------------------------------------------------------------------------
Vibratory
----------------------------------------------------------------------------------------------------------------
10- to 16-in timber pile............ NA 162 NA (Caltrans, 2020).
16-in steel pipe pile............... NA 163 NA (Caltrans, 2020).
24-in steel pipe pile............... NA 163 NA (U.S. Navy, 2012, U.S.
Navy, 2013, Miner,
2020).*
30-in steel pipe pile............... NA 166 NA (U.S. Navy, 2012, U.S.
Navy, 2013, Sexton,
2007, Laughlin, 2011,
Laughlin, 2017,
Miner, 2020).*
----------------------------------------------------------------------------------------------------------------
Impact
----------------------------------------------------------------------------------------------------------------
16-in steel pipe pile............... 200 185 175 (Caltrans, 2020).
24-in steel pipe piles.............. 203 190 177 (Caltrans, 2015).
[[Page 57566]]
30-in steel pipe piles.............. 210 190 177 (Caltrans, 2020)--
Russian River
Geyersville, CA;
Terminal Replacement,
Antioch, CA,
(Illingworth &
Rodkin, 2017)--
Philadelphia, PA;
(Austin et al.,
2016).*
----------------------------------------------------------------------------------------------------------------
* Methodology followed the U.S. Navy (2015) and included available data from Puget Sound, Washington, and
Southern Alaska.
Transmission Loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and seafloor composition
and topography. The general formula for underwater TL is:
TL = B x Log10(R<INF>1</INF>/R<INF>2</INF>),
where:
TL = transmission loss in dB,
B = transmission loss coefficient,
R<INF>1</INF> = the distance of the modeled SPL from the driven
pile, and
R<INF>2</INF> = the distance from the driven pile of the initial
measurement.
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 waters, such as those found in the PM
JNU Rock Dump Fuel Terminal Reconstruction Project area. 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 threshold isopleths.
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), PM calculated
distances to the Level A harassment and Level B harassment thresholds
and the 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-other-acoustic-tools">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools</a>). 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 to help predict
the amount of take that may occur incidental to an activity. We note
that because of some of the assumptions included in the methods
underlying this optional tool, we anticipate that the resulting
isopleth estimates are typically going to be overestimates of some
degree, which may result in an overestimate of potential take by Level
A harassment. However, this optional tool offers the best way to
estimate isopleth distances when more sophisticated modeling methods
are not available or practical. For stationary sources (i.e., vibratory
pile driving and removal, impact pile driving), the optional User
Spreadsheet tool predicts the distance at which, if a marine mammal
remained at that distance for the duration of the activity, it would be
expected to incur AUD INJ. Inputs used in the optional User Spreadsheet
tool include the source levels in table 5 and values in table 6 below.
Table 6--User Spreadsheet Input Parameters \1\ for Calculating Level A Harassment Threshold Isopleths for Pile
Driving and Removal
----------------------------------------------------------------------------------------------------------------
Minutes
Installation Max piles per Average piles (vibratory) or
Structure and pile parameters method \2\ day \3\ per day strikes per
pile (impact)
----------------------------------------------------------------------------------------------------------------
Pile Removal
----------------------------------------------------------------------------------------------------------------
Retaining Wall and Approach Dock (10''-16'' V 12 10 20
Timber piles).................................
Main Dock and Fuel Float (10''-16'' Timber V 12 8 20
piles)........................................
Breasting Dolphin (10''-16'' Timber piles)..... V 10 8 30
Mooring Dolphin (24'' steel pipe piles)........ V 6 5 30
Mooring Dolphin (30'' steel pipe piles)........ V 6 5 30
----------------------------------------------------------------------------------------------------------------
Temporary Piles
----------------------------------------------------------------------------------------------------------------
Template Construction Piles (24'' steel pipe V 12 8 60
piles)........................................
----------------------------------------------------------------------------------------------------------------
[[Page 57567]]
New Pile Installation
----------------------------------------------------------------------------------------------------------------
Mooring and Breasting Dolphins (30'' steel pipe V 2 1 180
piles)........................................ I 2,000
Approach and Main Dock (24'' steel pipe piles). V 2 1 120
I 1,200
Abutment (24'' steel pipe piles)............... V 4 3 90
I 600
Fender Piles (16'' steel pipe piles)........... V 6 5 90
I 400
Fender Piles (24'' steel pipe piles)........... V 5 4 90
I 400
Fuel Line Support Piles (16'' steel pipe piles) V 6 4 90
I 600
----------------------------------------------------------------------------------------------------------------
\1\ User Spreadsheet inputs--Vibratory pile driving tab A.1 (stationary source: non-impulsive, continuous), WFA
2; Impact pile driving tab E.1 (stationary source: impulsive, intermittent), WFA 2.5.
\2\ Installation methods include vibratory pile driving (V) and impact pile driving (I).
\3\ Estimates of the cumulative 24-hr sound energy exposure metric relevant for assessing the potential for
Level A harassment assumed the maximum piles/day rate.
Using the practical spreading model, NMFS determined that the
underwater noise would yield the following calculated distances to the
Level A harassment and Level B harassment thresholds for marine mammals
(table 7).
Table 7--Calculated Distances to Level A Harassment and Level B Harassment Isopleths for Pile Driving and
Removal
----------------------------------------------------------------------------------------------------------------
Distance to Level A harassment isopleth (m) Level B
--------------------------------------------------------- harassment
Structure and pile parameters Method \a\ Humpback Killer Harbor Harbor Steller zones (m)
whales whales porpoise seals sea lions \b\
----------------------------------------------------------------------------------------------------------------
Pile Removal
----------------------------------------------------------------------------------------------------------------
10''-16'' Timber piles (All V 27.1 10.4 22.1 34.9 11.7 6,309.6
relevant structures)........
Mooring Dolphin (24'' steel V 26.1 10.0 21.3 33.6 11.3 7,356.4
pipe piles).................
Mooring Dolphin (30'' steel V 41.3 15.9 33.8 53.2 17.9 11,659.1
pipe piles).................
----------------------------------------------------------------------------------------------------------------
Temporary Piles
----------------------------------------------------------------------------------------------------------------
Template Construction Piles V 65.7 25.2 53.7 84.6 28.5 7,356.4
(24'' steel pipe piles).....
----------------------------------------------------------------------------------------------------------------
New Pile Installation
----------------------------------------------------------------------------------------------------------------
Mooring and Breasting V 65.6 25.2 53.6 84.4 28.4 11,659.1
Dolphins (30'' steel pipe I 998.2 127.4 1,544.7 886.8 330.5 1,000
piles)......................
Approach and Main Docks (24'' V 31.6 12.1 25.8 40.7 13.7 7,356.4
steel pipe piles)........... I 710.1 90.6 1,098.9 630.9 235.1 1,000
Abutment (24'' steel pipe V 41.4 15.9 33.8 53.3 17.9 7,356.4
piles)...................... I 710.1 90.6 1,098.9 630.9 235.1 1,000
Fender Piles (16'' steel pipe V 54.2 20.8 44.3 69.8 23.5 7,356.4
piles)...................... I 522.4 66.6 808.3 464 173 464.2
Fender Piles (24'' steel pipe V 48 18.5 39.2 61.8 20.8 7,356.4
piles)...................... I 628.8 80.2 973.2 558.7 208.2 1,000
Fuel Line Support Piles (16'' V 54.2 20.8 44.3 69.8 23.5 7,356.4
steel pipe piles)........... I 684.5 87.3 1,059.2 608.1 226.7 464.2
----------------------------------------------------------------------------------------------------------------
\a\ Installation methods include vibratory pile driving (V) and impact pile driving (I).
\b\ These isopleths are truncated by land at approximately 3,550 m during high tide and approximately 2,230 m at
low tide.
Marine Mammal Occurrence
In this section, we provide information about the occurrence of
marine mammals, including density or other relevant information, which
will inform the take calculations. Available information regarding
marine mammal occurrence in the project area includes monitoring data,
previous monitoring reports, and consultation with local researchers
and marine professionals. Occurrence estimates for each species
[[Page 57568]]
factor in historic occurrence data, seasonality, and estimated group
size in Gastineau Channel, as described below. Section 6 of PM's
application provides additional information regarding literature and
sources cited.
Humpback whales are common in southeast Alaska, especially during
the summer, but they rarely transit through Gastineau Channel, with
only occasional sightings (PND Engineers, 2026). During monitoring
conducted by previous IHA holders, sightings either did not occur or
were rare (City of Borough of Juneau (CBJ), Docks & Harbors, 2018; CBJ,
Docks & Harbors, 2020; CBJ, Docks & Harbors, 2024; Sailfin Marine
Observing & Consulting, LLC, 2021; Uchytil, Michrowski, and Easterly,
2020). However, anecdotal reports indicate humpback whales do
intermittently pass through the project area near downtown Juneau (PND
Engineers, 2026). NMFS estimates three individual humpback whales would
occur per month in the Level B harassment zone.
Killer whales occasionally occur in Gastineau Channel. Killer whale
sightings in the project area reported in Happy Whale include 2019 and
2020 sightings of four and seven individuals, respectively, followed by
sightings of a single individual near the Juneau-Douglas Bridge in
March 2021 and another sighting of seven individuals in May 2021 (PND
Engineers, 2026). NMFS reviewed eight Protected Species Observer (PSO)
monitoring reports from the Juneau area (including Auke Bay, north of
the Gastineau Channel) from 2019-2024. Three out of the eight reports
included sightings of killer whales. Over a collective 254 days of
monitoring, PSOs observed six groups of killer whales (group sizes
ranged from two to six) for a total of 25 killer whales, or
approximately 0.1 whales per day (25 whales/254 days or 3 whales per
month). The maximum group size among anecdotal and monitoring reports
was 7 individuals. Recognizing the frequency of occurrence is variable
and killer whales can be present more frequently in summer for which
data is lacking, NMFS estimates one group of seven individuals would
occur per month (or more than one group of a smaller number of
individuals) in the Level B harassment zone.
Sightings of harbor porpoises near downtown Juneau are relatively
rare, although there are occasional reports of groups of two to four
animals in Gastineau Channel. In September of 1992, the National Marine
Mammal Laboratory Harbor Porpoise Vessel observed two harbor porpoises
in Gastineau Channel southeast of downtown Juneau near the community of
Thane (Global Biodiversity Information Center (GBIF) 2025). PSOs
monitoring during construction of the Downtown Juneau Waterfront
Improvements Project in February 2020 detected a group of four harbor
porpoises (Uchytil, Michrowski, and Easterly, 2020). No harbor
porpoises were sighted during marine mammal monitoring for the Aurora
Harbor Rebuild--Phase II project between November 2017 and March 2018
(CBJ, Docks & Harbors, 2018). Alaska Fish and Wildlife News describes
observations of a pair of harbor porpoises near the Juneau-Douglas
Bridge in February 2024 (ADF&G, 2024). NMFS estimates one group of four
individuals per month would occur in the Level B harassment zone.
Although rare near downtown Juneau, SSL sightings do occur
regularly in Gastineau Channel. The Douglas Island Pink and Chum, Inc.
(DIPAC) salmon hatchery is located along the Gastineau Channel,
approximately 5.5 km (3.4 mi) northwest of downtown Juneau. DIPAC staff
noted that in the summer (July through September) they see one to two
SSLs per day in the water near the hatchery. Outside of those months,
staff estimate they only see one to two SSLs for the remainder of the
year (PND Engineers, 2026). During marine mammal monitoring over 58
days for the Downtown Juneau Waterfront Improvements Project in 2020,
PSOs sighted a group of eight SSLs in February; no other SSLs were
reported from December through the project completion in April
(Uchytil, Michrowski, and Easterly, 2020). SSLs were observed on three
occasions during monitoring for the Aurora Harbor Rebuild--Phase II
project: a single adult in November; a group of three in December; and
a single adult in February. The group of three SSLs was observed
milling near the mouth of Kowee Creek just north of the Juneau-Douglas
Bridge (CBJ, Docks & Harbors 2018). PSOs monitoring during a dredging
project in December 2024, noted a single adult female traveling
northwest in the Gastineau Channel near DIPAC; no other SSLs were
observed in the area during the project (City & Borough of Juneau,
Docks and Harbors, 2025). Given the proximity of the PM project area to
DIPAC, NMFS estimates that two individuals per day would occur in the
Level B harassment zone.
Harbor seals are one of the most frequently sighted marine mammals
in the project area. During marine mammal monitoring for the Downtown
Juneau Waterfront Improvements Project in 2020, harbor seals were
present in the project area on most days, and the monitoring report
suggests that a resident group of around 10-12 harbor seals uses
Gastineau Channel in the winter (Uchytil, Michrowski, and Easterly
2020). During marine mammal monitoring for the Aurora Harbor Rebuild--
Phase II Project between November 2017 and March 2018, 466 harbor seals
were sighted over approximately 273 observation hours (CBJ, Docks &
Harbors 2018). PSOs sighted a total of 17 harbor seals over
approximately 32 of monitoring during the Aurora Harbor Rebuild--Phase
III project in December 2023 through February 2024 (CBJ, Docks &
Harbors, 2024). All sightings were of single individuals, except for
one sighting of a pair (CBJ, Docks & Harbors, 2024). A total of 26
harbor seals were observed over 12.5 hours of monitored construction
for the Harris Harbor Pile Driving project in February 2021. PSOs for
the project note that these sightings were likely of the same few
individuals and estimated that there were approximately three to five
individual resident harbor seals in the project area in Harris Harbor
(Sailfin Marine Observing & Consulting, LLC. 2021). Harbor seals haul
out on the shoals near DIPAC (Alaska Fisheries Science Center [AFSC]
2025). This area is not known to be a key haulout for harbor seals;
however, moderate numbers of seals move up Gastineau Channel toward
this haulout during hatchery releases. Using marine mammal monitoring
data collected during construction of previous projects near downtown
Juneau, PM calculated the average number of harbor seals sighted per
day across the observation periods (n=18). Based on PM's calculation,
NMFS estimates 18 harbor seals per day would occur in the Level B
harassment zone.
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 proposed for authorization.
Estimated take was calculated based on either daily or monthly
occurrence estimates for each species, using the following formulas:
Estimated take (daily) = group size x groups per day x days of pile
driving; and
Estimated take (monthly) = group size x groups per month x months of
pile driving activity, where one month is a 30-day period.
The equation for daily estimated take was used for species whose
occurrence
[[Page 57569]]
was ``common'' and therefore had a daily occurrence estimate (harbor
seals, Steller sea lions). The equation for monthly estimated take was
used for all other species. The estimated take value was rounded to the
nearest whole number at the end of the calculation.
While NMFS expects take to be primarily by Level B harassment, PM
requested, and NMFS is proposing to authorize take by Level A
harassment (AUD INJ) for three species: harbor porpoise, harbor seal,
and Steller sea lion.
NMFS does not anticipate that harbor porpoises would incur AUD INJ
incidental to PM's construction activities. Harbor porpoises are
behaviorally sensitive species, and it is well documented they exhibit
strong avoidance reactions to noise such as pile driving. It is
unlikely that a harbor porpoise would occur and remain within the Level
A harassment zone for a long enough duration to incur AUD INJ. However,
PM requested take of harbor porpoise by Level A harassment, citing the
following reasons. For impact pile driving activities, PM is proposing
a 300-m shutdown zone that is smaller than the largest Level A
harassment zones which, depending on the pile type, range from 808 m to
1,545 m. Additionally, harbor porpoises are small, cryptic, and surface
briefly, which can limit the probability of detection by PSOs at
distances greater than a few hundred meters, particularly when sighting
conditions are suboptimal (e.g., glare, wave chop, reduced light).
Although AUD INJ is not anticipated, PM requested, and therefore, NMFS
proposes to authorize take by Level A harassment of 1 harbor porpoise
per month over the 3 months that project may occur, for a total of 3
takes by Level A harassment).
For harbor seals, the proposed 25-m shutdown zone for impact pile
driving is small compared to the Level A harassment zones, which range
from 525 m to 1,000 m. PM anticipates, and NMFS concurs, that harbor
seals could enter the Level A harassment zone and remain in the zone
for a long enough duration to incur PTS. As indicated in table 6,
impact pile driving would be conducted on 47 of the 81 (i.e., 58
percent) in-water construction days. Thus, PM assumed that 58 percent
of the total estimated take (n=1,458) could be by Level A harassment
(n=846) and the remainder of the estimated takes would be by Level B
harassment (n=612). Given impact pile driving will be intermittent
throughout the day, harbor seals would likely have auditory recovery
time following any exposure. However, to avoid underestimating the
potential for AUD INJ, NMFS is proposing to authorize 846 takes by
Level A harassment.
PM requested authorization of several instances of take by Level A
harassment for SSLs due to the species' crypticity, potentially high
abundance during the construction period, and the project's proximity
to foraging habitat. SSLs can be difficult to detect in water because
they surface briefly and provide only a small surface expression. Given
PM's construction schedule, project activities could overlap peaks in
SSL abundance (i.e., during the salmon run). PM's proposed shutdown
zones are equal to or larger than the Level A harassment zones, thus
NMFS anticipates that take by Level A harassment of SSLs is unlikely.
However, PM requested, and NMFS is proposing to authorize, take of one
SSL by Level A harassment per month (three takes by Level A harassment
total) in the event that an SSL enters, and remains unobserved within,
the Level A harassment zone for a long enough duration to incur AUD INJ
before a shutdown occurs.
No Level A harassment is anticipated for killer whales or humpback
whales. Both species are large bodied with pronounced external blows
and are, thus, more easily detected by PSOs. Additionally, the proposed
shutdown zones for each species are equal to or exceed the Level A
harassment zones for the relevant hearing group.
Table 8 summarizes take by both Level A harassment (AUD INJ) and
Level B harassment proposed to be authorized, as well as estimated
takes as a percentage of stock abundance.
Table 8--Summary of the Proposed Take for JNU Rock Dump Fuel Terminal Reconstruction Project
----------------------------------------------------------------------------------------------------------------
Percentage of
total stock
Species Stock Abundance Level A Level B Total proposed for
harassment harassment authorization
\1\
----------------------------------------------------------------------------------------------------------------
Humpback whale \2\............. Hawaii........... 11,278 0 8 8 <1
Killer whale \3\............... Eastern North 1,920 0 21 21 1.1
Pacific Alaska
resident.
Gulf of Alaska/ 587 3.6
Aleutian Islands/
Bering Sea
Transient.
Eastern North 302 7
Pacific Northern
Resident.
West Coast 349 6
Transient.
Harbor porpoise................ Northern 1,619 3 8 11 0.7
Southeast Alaska
Inland Waters.
Steller sea lion \4\........... Western.......... 49,837 0 2 2 0
Eastern.......... 36,308 3 159 162 0.4
Harbor seal.................... Lynn Canal/ 13,388 846 612 1,458 10.9
Stephens Passage.
----------------------------------------------------------------------------------------------------------------
\1\ Percent of stock refers to combined take by both Level B harassment and Level A harassment (where
requested).
\2\ 98 percent of humpback whales in the project area are expected to be from the Hawai'i stock and 2 percent
from the Mexico-North Pacific stock. Thus, of the low number of total estimated takes for humpback whales
(n=8), this equates to 7.84 and 0.16 estimated takes of humpback whales from the Hawai'i and Mexico-North
Pacific stocks, respectively. After applying standard rounding, NMFS is not proposing to authorize take of the
Mexico-North Pacific stock of humpback whales.
\3\ Scientific data is not available to determine the likelihood of each killer whale stock in PM's proposed
project area, and the stocks cannot be differentiated in the field. When calculating the percentage of stock,
NMFS assumes all takes may occur to each killer whale stock.
\4\ SSL DPS attribution: 98.6 percent Eastern DPS and 1.4 percent Western DPS.
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses. NMFS regulations require applicants for incidental
take authorizations to include information about the availability and
feasibility (economic and technological) of equipment, methods, and
manner of conducting the activity or other means of effecting the least
practicable adverse impact upon the affected species or
[[Page 57570]]
stocks, and their habitat (50 CFR 216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat, as
well as subsistence uses. This considers the nature of the potential
adverse impact being mitigated (likelihood, scope, range). It further
considers the likelihood that the measure will be effective if
implemented (probability of accomplishing the mitigating result if
implemented as planned), the likelihood of effective implementation
(probability implemented as planned); and
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost, and impact on
operations.
The mitigation requirements described in the following were
proposed by PM in its adequate and complete application or are the
result of subsequent coordination between NMFS and PM. PM has agreed
that all of 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 the proposed measures are
appropriate. NMFS describes these below as proposed mitigation
requirements and has included them in the proposed IHA.
In addition to the measures described later in this section, PM
would follow these general mitigation measures:
<bullet> Ensure that construction supervisors and crews, the marine
mammal monitoring team, and relevant staff are trained prior to the
start of all construction activities, so that responsibilities,
communication procedures, marine mammal monitoring protocol, and
operational procedures are clearly understood. New personnel joining
during the project must be trained prior to commencing work;
<bullet> Employ PSOs and establish monitoring locations as
described in the Protected Species Monitoring and Mitigation Plan
(PSMMP). PM must monitor the project area to the maximum extent
possible based on the required number of PSOs, required monitoring
locations, and environmental conditions; and
<bullet> PM also would abide by the reasonable and prudent measures
and terms and conditions of a Biological Opinion and Incidental Take
Statement, if issued by NMFS, pursuant to Section 7 of the ESA.
Additionally, the following mitigation measures apply to PM's in-
water construction activities.
Establishment of Clearance and Shutdown Zones
PM proposed and NMFS would require the establishment of the
clearance and shutdown zones identified in table 9 for all pile driving
activities. The purpose of a clearance zone is to prevent potential
instances of auditory injury and more severe behavioral disturbance to
the maximum extent practicable by delaying the commencement of pile
driving if marine mammals are detected within certain pre-defined
distances from the pile being installed. The purpose of a shutdown is
to prevent a specific, acute impact, such as auditory injury or more
severe behavioral disturbance, by halting the activity. Additionally,
to avoid unauthorized takes, PM would delay an activity or shut down in
the event that a species for which take is not authorized or for which
take has been reached is observed within or entering any designated
harassment zone. If pile driving activities are 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 clearance and shutdown zones indicated in table 9
or 15 minutes have passed without re-detection of the animal.
If a marine mammal comes within 10 meters of such activity,
operations must cease and vessels must reduce speed to the minimum
level required to maintain steerage and safe working conditions, as
necessary to avoid direct physical interaction.
In general, the clearance and shutdown zones represent the
calculated Level A harassment distance rounded up for ease of
implementation (table 9). However, the proposed IHA includes shutdown
zones that are smaller than the Level A harassment zones (table 7) for
harbor porpoises (300-m shutdown zone) and harbor seals (25-m shutdown
zone) due to detectability concerns (i.e., both species are cryptic).
In addition, harbor seals are frequently observed in close proximity to
project sites, sometimes approaching active pile-driving sites (e.g.,
CBJ, 2019). Therefore, PM asserts, and NMFS concurs, that a larger
mitigation zone for harbor seals would not be practicable due to the
potential for frequent delays or shutdowns. For both species, NMFS is
proposing to authorize take by Level A harassment to account for the
fact that the species-specific proposed shutdown zone is smaller than
the maximum Level A harassment zone.
Table 9--Proposed Shutdown Zones (m) and Level B Harassment Zones During Activities for the JNU Rock Dump Fuel Terminal Reconstruction Project
--------------------------------------------------------------------------------------------------------------------------------------------------------
Shutdown zones (m)
-------------------------------------------------------------------------- Level B
Structure and pile parameters Installation Harbor porpoise \2\ Harbor seals \2\ harassment
method \1\ Humpback Killer Steller ----------------------------------------- zones (m)
whales whales sea lions Reduced Full Reduced Full \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
10''-16'' Timber Piles (All Relevant Structures) V 30 15 15 25 25 25 35 6,310
Mooring Dolphin (24'' Steel Pipe Piles)......... V 30 10 15 25 25 25 35 7,360
Mooring Dolphin (30'' Steel Pipe Piles)......... V 45 20 20 35 35 25 55 11,660
--------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Template Construction Piles (24'' Steel Pipe V 70 30 30 55 55 25 85 7,360
Piles).........................................
--------------------------------------------------------------------------------------------------------------------------------------------------------
New Pile Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mooring and Breasting Dolphins (30'' Steel Pipe V 70 30 30 55 55 25 85 11,660
Piles).........................................
[[Page 57571]]
I 1,000 130 335 300 1,545 25 890 1,000
Approach and Main Docks (24'' Steel Pipe Piles). V 35 15 15 30 30 25 45 7,360
I 715 95 240 300 1,100 25 635 1,000
Abutment (24'' Steel Pipe Piles)................ V 45 20 20 35 35 25 55 7,360
I 715 95 240 300 1,100 25 635 1,000
Fender Piles (16'' Steel Pipe Piles)............ V 55 25 25 45 45 25 70 7,360
I 525 70 175 300 810 25 465 470
Fender Piles (24'' Steel Pipe Piles)............ V 50 20 25 40 40 25 65 7,360
I 630 85 210 300 975 25 560 1,000
Fuel Line Support Piles (16'' Steel Pipe Piles). V 55 25 25 45 45 25 70 7,360
I 685 90 230 300 1,060 25 610 470
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Installation methods include vibratory pile driving (V) and impact pile driving (I).
\2\ PM would implement reduced shutdown zones for harbor porpoises and harbor seals until the species-specific number of takes by Level A harassment
NMFS is proposing to authorize has been met, after which PM would implement a full shutdown zone that is equal to or greater than the maximum Level A
harassment zone.
\3\ These isopleths are truncated by land at approximately 3,550 m during high tide and approximately 2,230 m at low tide.
Pre- and Post-Activity Monitoring
Monitoring would take place from 30 minutes prior to initiation of
pile driving (pre-start clearance monitoring) through 30 minutes post-
completion of pile driving. In addition, monitoring for 30 minutes
would take place whenever a break in the specified activity (i.e.,
impact or vibratory pile driving) of 30 minutes or longer occurs. Pre-
start clearance monitoring would be conducted during periods of
visibility sufficient for PSOs to determine that the clearance zones
indicated in table 9 are clear of marine mammals. Pile driving may
commence following 30 minutes of observation when the determination is
made that the clearance zones are clear of marine mammals.
Soft Start
PM would use soft start procedures for impact pile driving to
provide additional protection to 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 required contractors to provide
an initial set of three strikes as reduced energy, followed by a 30-
second waiting period, then two subsequent reduced-energy strike sets.
This soft start would be implemented at the start of each day's impact
pile driving and at any time following cessation of this activity for a
period of 30 minutes or longer within a day.
Bubble Curtains
PM has not proposed to use a bubble curtain during impact pile
driving due to limited effectiveness of the bubble curtains due to the
strong tides in the area and economic impracticability. In general,
bubble curtains reduce noise levels near the source, minimizing
exposure level. However, for this project, most of the piles are
located within the intertidal zone, and thus a substantial number of
piles will be installed above water or with the limits of the bubble
curtain above the water surface preventing the bubble curtains from
being effective. In addition, bubble curtains would be cost prohibitive
and would prevent the project from going forward. For these reasons, PM
has determined that the use of a bubble curtain is not practicable, and
NMFS agrees.
NMFS conducted an independent evaluation of the proposed measures
and has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, areas of similar significance,
and on the availability of such species or stock for subsistence uses.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and Mitigation and monitoring effectiveness.
The monitoring and reporting requirements described in the
following were proposed by PM in its adequate and complete application
and/or are the result of subsequent coordination between NMFS and PM.
PM has agreed to the requirements. NMFS describes
[[Page 57572]]
these below as requirements and has included them in the proposed IHA.
Proposed Monitoring
A minimum of two PSOs would be on duty during all pile-driving
activities. All PSOs must be NMFS-approved. PSOs would be independent
of the activity contractor (for example, employed by a subcontractor)
and have no other assigned tasks during monitoring periods. At least
one PSO would have prior experience performing the duties of a PSO
during an activity pursuant to a NMFS issued Incidental Take
Authorization (ITA) or Letter of Concurrence (LOC). Other PSOs may
substitute other relevant experience (including relevant Alaska Native
traditional knowledge), education (degree in biological science or
related field), or training for prior experience performing the duties
of a PSO during construction activity pursuant to a NMFS-issued
incidental take authorization. Where a team of three or more PSOs is
required a lead observer or monitoring coordinator would be designated.
The lead observer must have prior experience performing the duties of a
PSO during construction activity pursuant to a NMFS-issued ITA or LOC.
PSOs will be positioned at the best practicable vantage points,
taking into consideration security, safety, access, and space
limitations. Observer locations must be identified that (1) have an
unobstructed view of the work being conducted and (2) unobstructed view
of all the water within the Level A harassment zone and as much of the
Level B harassment zone as possible. Potential observation locations
are depicted in Figure 1 of PM's PSMMP. Optimal observation locations
will be selected based on visibility and the type of work occurring.
Reporting
PM would submit a draft report on all construction activities and
marine mammal monitoring results to NMFS within 90 calendar 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. PM will provide a final report to NMFS within 30 days
following receipt of any NMFS' comments on the draft report. 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. PM would also be required to submit reports on any observed
injured or dead marine mammals. If the death or injury was clearly
caused by a specified activity, the PM would immediately cease the
specified activities until NMFS is able to review the circumstances of
the incident and determine what, if any, additional measures are
appropriate to ensure compliance with the terms of the IHA. PM would
not resume its activities until notified by NMFS.
Specific proposed 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 on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the discussion of our analysis applies to all
species listed in table 2 given that the anticipated effects of this
activity on these different marine mammal stocks are expected to be
similar. There is little information about the nature or severity of
the impacts, or the size, status, or structure of any of these species
or stocks that would lead to a different analysis for this activity.
Impact and vibratory pile driving and removal have the potential to
disturb or displace marine mammals and may result in take in the form
of Level B harassment for all species and stocks in table 2 and Level A
harassment for harbor porpoises, harbor seals, and SSLs. Potential
takes could occur if individuals of these species are present in Level
B harassment identified above when these activities are underway. PM
would implement mitigation measures designed to reduce the potential
for and severity of harassment on the affected marine mammal species
and stocks during the specified activities.
Given the nature of PM's proposed activities, NMFS does not
anticipate serious injury or mortality, even in the absence of required
mitigation. Take by Level A harassment is proposed for harbor
porpoises, harbor seals, and SSLs to account for the potential that an
animal could enter and remain in the Level A harassment zone unnoticed
for a duration long enough to be taken by Level A harassment. Any take
by Level A harassment is expected to arise from, at most, a small
degree of AUD INJ because animals would need to be exposed to higher
levels and/or longer duration than are expected to occur here in order
to incur any more than a small degree of AUD INJ. Further, PTS would
only occur within the frequency range of the source (i.e., impact pile
driving) which does not cover any species complete hearing range. For
most species, the frequency range of the noise produced by the
specified activities is outside their primary hearing range.
Additionally, some subset of the individuals that are behaviorally
harassed could also simultaneously incur some small degree of TTS for a
short duration of time. Because of the small degree anticipated, any
AUD INJ or TTS potentially incurred here is not expected to adversely
impact individual fitness, let alone annual rates of recruitment or
survival.
For all species and stocks, take is expected to occur within a
limited, confined area (adjacent to the project site) of the species'
range, including Southeast Alaska. The intensity and duration of take
by Level A harassment and/or Level B harassment would be minimized
through the proposed mitigation measures described herein. Further, the
number of take proposed
[[Page 57573]]
for each species is small when compared to stock abundance.
Behavioral responses of marine mammals to pile removal and
installation at the JNU Rock Dump Fuel Terminal are expected to be
mild, short-term, and temporary. 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. Given that pile removal and
installation activities would only occur on a limited number of days
each year, often on non-consecutive days, any harassment would be
temporary. Additionally, many of the species present in the Gastineau
Channel would be present only for part of the year, based on seasonal
patterns or during active transit between other habitats. These species
would be exposed to even shorter periods of noise-generating activity,
further decreasing the impacts.
Most likely, during the specified activities, individuals are
expected to move away from the sound source until the source ceases. An
avoidance response is most likely to occur if an animal is in close
proximity to a source, most notably impact pile driving. At distance,
the severity of any behavioral response is likely to be diminished from
all of the specified activities. It is possible that avoidance or other
behavioral responses do not occur, especially for non-impulsive sources
such as vibratory pile removal and driving, given marine mammals in the
Juneau area are consistently exposed to anthropogenic noise sources
like vessel traffic. Regardless, NMFS assumes animals disturbed by
project sounds would be expected to avoid the area and use nearby
higher-quality habitats.
The potential for harassment is minimized through the
implementation of the proposed mitigation measures. The use of shutdown
and clearance zones reduce the likelihood of incurring AUD INJ. During
impact driving, implementation of soft start procedures shall be
required, reducing possibility for injury. Through the use of soft
start during impact pile driving, marine mammals are expected to move
away from a disturbing sound source prior to it becoming potentially
injurious.
Any impacts on prey that would occur during in-water construction
would have at most short-term effects on foraging of individual marine
mammals, and likely no effect on the populations of marine mammals as a
whole. Therefore, effects on marine mammal prey during the construction
are expected to be minimal and, therefore, are unlikely to cause
substantial effects on marine mammals at the individual or population
level.
In addition, it is unlikely that minor noise effects in a small,
localized area of habitat would have any effect on the reproduction or
survival of any individual, much less the stocks' annual rates of
recruitment or survival. In combination, we believe that these factors,
as well as the available body of evidence from other similar
activities, demonstrated that the potential effects of the specified
activities would have only short-term effects on individuals. The
specified activities are not expected to impact rates of recruitment or
survival and would, therefore, not result in population-level impacts.
For humpback whales, the inland waters of Southeast Alaska are a
seasonal feeding BIA from May through September (Wild et al., 2023).
However, the portion of Gastineau Channel near the project area is not
included in the feeding BIA, thus, the ensonified area from PM's
proposed activities would not overlap with important foraging habitat.
We do not expect PM's proposed construction to have any effect on
humpback whales' ability to forage.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect any of the species
or stocks through effects on annual rates of recruitment or survival:
<bullet> No serious injury or mortality is anticipated or
authorized;
<bullet> Any Level A harassment is anticipated to be slight AUD
INJ, including slight PTS of a few decibels within the lower
frequencies associated with pile driving and not encompassing a
species' full hearing range;
<bullet> The anticipated incidents of Level B harassment would
result in, at worst, temporary modifications in behavior or a small
degree of TTS that would resume to baseline at the cessation of
activities or as animals move away from the source;
<bullet> The project area is located in a highly industrialized and
commercial area; therefore, species taken are likely acclimated to
anthropogenic activities and behavioral reactions are expected to be
minor;
<bullet> Take could occur within an exceedingly small area affected
by the specified activity relative to the overall habitat ranges of all
species, and it does not include any rookeries nor does it overlap any
known BIAs or ESA-designated critical habitat;
<bullet> Effects on species that serve as prey for marine mammals
from the activities are primarily 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;
<bullet> The proposed mitigation measures, such as soft starts for
impact pile driving and shutdown zones, are expected to reduce the
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 will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted previously, only take of small numbers of marine mammals
may be authorized under section 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. When the predicted number of
individuals to be taken is fewer than one-third of the species or stock
abundance, the take is considered to be of small numbers (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. As previously stated, no mortality or serious injury
has been requested, nor is it anticipated to occur from the activities
described herein.
The number of instances of take for each species or stock proposed
for authorization are included in table 8. Our analysis shows that for
all species with available population abundance estimates, less than
one-third of the best available population abundance estimate of each
stock could be taken by harassment incidental to the proposed
construction.
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
[[Page 57574]]
taken relative to the population size of the affected species or
stocks.
Unmitigable Adverse Impact Analysis and Determination
In order to issue an IHA, NMFS must find that the specified
activity will not have an ``unmitigable adverse impact'' on the
subsistence uses of the affected marine mammal species or stocks by
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50
CFR 216.103 as an impact resulting from the specified activity: (1)
that is likely to reduce the availability of the species to a level
insufficient for a harvest to meet subsistence needs by: (i) causing
the marine mammals to abandon or avoid hunting areas; (ii) directly
displacing subsistence users; or (iii) placing physical barriers
between the marine mammals and the subsistence hunters; and (2) that
cannot be sufficiently mitigated by other measures to increase the
availability of marine mammals to allow subsistence needs to be met.
Alaska Natives have traditionally harvested subsistence resources,
including sea lions and harbor seals, in Southeast Alaska. Since
surveys of harbor seal and sea lion subsistence harvest in Alaska began
in 1992, there have been declines in the number of households hunting
and harvesting pinnipeds in Southeast Alaska while the number of
household hunting and harvesting sea lions has remained relatively
constant at low levels (Wolfe et al. 2013). Subsistence harvest data
for the Lynn Canal/Stephens Passage stock indicates an average annual
harvest in the years 2004-2008 of 69 harbor seals; in 2011, 42 seals
were harvested, and 24 seals were harvested in 2012 (summarized in Muto
et al. 2016 from Wolfe et al. 2013). In 2012, the community of Juneau
had an estimated subsistence take of zero SSL (Wolfe et al. 2013).
The ADF&G has designated the area around Juneau, including
ensonified waters from the project, a non-subsistence area, defined as
an area where dependence upon subsistence (customary and traditional
uses of fish and wildlife) is not a principal characteristic of the
economy, culture, and way of life (AS 16.05.258(c)). Regardless, the
impact of the project on marine mammals is expected to be primarily
limited to mild behavioral reactions (e.g., avoidance during pile
activities, increased swim speeds, or cessation of vocalizations) such
that it would not affect their availability for subsistence use.
Given all of this information, NMFS has preliminarily determined
that authorizing the take requested by PM is not likely to adversely
affect the availability of any marine mammal species/stocks that would
traditionally be used for subsistence purposes or would affect any
subsistence harvest.
<bullet> The proposed construction activities are spatially
localized within an existing waterfront development wherein marine
mammals have become acclimated to human activity;
<bullet> The proposed activities are temporary in nature;
PM would implement mitigation measures that minimize any harassment
to marine mammals in the action area, including traditionally harvested
species;
<bullet> NMFS expects that most of the effects on marine mammals
would not rise above behavioral impacts (i.e., Level B harassment) and
would be temporary in nature and any AUD INJ (i.e., Level A harassment)
that may occur would be a slight threshold shift and would be limited
to a few instances of take; and
<bullet> No serious injury or mortality is expected or proposed to
be authorized.
For these reasons, NMFS has preliminarily determined that there
will not be an unmitigable adverse impact on subsistence uses from
authorizing the requested take that may occur incidental to PM's
specified 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 ensures that any action it
authorizes, funds, or carries out is not likely to jeopardize the
continued existence of any endangered or threatened species or result
in the destruction or adverse modification of designated critical
habitat. To ensure ESA compliance for the issuance of incidental take
authorizations, NMFS consults internally whenever we propose to
authorize take for ESA-listed species, in this case with the NMFS
Alaska Regional Office (AKRO).
NMFS Office of Protected Resources (OPR) is proposing to authorize
take of the western stock of Steller sea lions, which are listed under
the ESA. OPR has requested initiation of section 7 consultation with
AKRO for the issuance of this IHA. NMFS will conclude the ESA
consultation prior to reaching a determination regarding the proposed
issuance of the authorization.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to PM for conducting construction in Juneau, AK, provided
the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated. A draft of the proposed IHA can be found
at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA for the proposed
construction. We also request comment on the potential renewal of this
proposed IHA as described in the paragraph below. Please include with
your comments any supporting data or literature citations to help
inform decisions on the request for this IHA or a subsequent renewal
IHA.
On a case-by-case basis, NMFS may issue a one-time, 1-year renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activity section of this notice is planned or (2) the activities as
described in the Description of Proposed Activity section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
<bullet> A request for renewal is received no later than 60 days
prior to the needed renewal IHA effective date (recognizing that the
renewal IHA expiration date cannot extend beyond 1 year from expiration
of the initial IHA).
<bullet> The request for renewal must include the following:
1. An explanation that the activities to be conducted under the
requested renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
2. A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
<bullet> Upon review of the request for renewal, the status of the
affected species or stocks, and any other pertinent information, NMFS
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures will remain the same and
appropriate,
[[Page 57575]]
and the findings in the initial IHA remain valid.
Dated: September 4, 2026.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2026-18458 Filed 9-9-26; 8:45 am]
BILLING CODE 3510-22-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.