Notice2026-04885
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the City of Kodiak St. Herman Harbor Infrastructure Rebuild Project Kodiak, Alaska
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
March 13, 2026
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from the City of Kodiak for authorization to take marine mammals incidental to 2 years of construction activities associated with the St. Herman Harbor Infrastructure Rebuild Project (SHHIRP) in Kodiak, Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue two consecutive 1-year incidental harassment authorizations (IHAs) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on possible one- time, 1-year renewals 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 authorizations and agency responses will be summarized in the final notice of our decision.
Full Text
<html>
<head>
<title>Federal Register, Volume 91 Issue 49 (Friday, March 13, 2026)</title>
</head>
<body><pre>
[Federal Register Volume 91, Number 49 (Friday, March 13, 2026)]
[Notices]
[Pages 12363-12392]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-04885]
-----------------------------------------------------------------------
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XF538]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the City of Kodiak St. Herman
Harbor Infrastructure Rebuild Project Kodiak, 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.
-----------------------------------------------------------------------
SUMMARY: NMFS has received a request from the City of Kodiak for
authorization to take marine mammals incidental to 2 years of
construction activities associated with the St. Herman Harbor
Infrastructure Rebuild Project (SHHIRP) in Kodiak, Alaska. Pursuant to
the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on
its proposal to issue two consecutive 1-year incidental harassment
authorizations (IHAs) to incidentally take marine mammals during the
specified activities. NMFS is also requesting comments on possible one-
time, 1-year renewals 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 authorizations and agency responses will be summarized in the
final notice of our decision.
DATES: Comments and information must be received no later than April
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#014855512f65646c6073647275416f6e60602f666e77"><span class="__cf_email__" data-cfemail="7f362b2f511b1a121e0d1a0c0b3f11101e1e51181009">[email protected]</span></a>.
Electronic copies of the application and supporting documents, as well
as a list of the references cited in this document, may be obtained
online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>. In
case of problems accessing these documents, please call the contact
listed below.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a> without change. All personal identifying
information (e.g., name, address) voluntarily submitted by the
commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: Austin Demarest, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the
[[Page 12364]]
taking will have a negligible impact on the species or stock(s) and
will not have an unmitigable adverse impact on the availability of the
species or stock(s) for taking for subsistence uses (where relevant).
Further, NMFS must prescribe the permissible methods of taking and
other ``means of effecting the least practicable adverse impact'' on
the affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (collectively 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
and can be found in section 3 of the MMPA (16 U.S.C. 1362) and NMFS
regulations at 50 CFR 216.103.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or
mortality) of the Companion Manual for NAO 216-6A, which do not
individually or cumulatively have the potential for significant impacts
on the quality of the human environment and for which we have not
identified any extraordinary circumstances that would preclude this
categorical exclusion. Accordingly, NMFS has preliminarily determined
that the issuance of the proposed IHA qualifies to be categorically
excluded from further NEPA review.
Summary of Request
On February 26, 2025, NMFS received a request from the City of
Kodiak for two consecutive IHAs to take marine mammals incidental to
pile driving (installation and removal), down-the hole (DTH) drilling
and hydraulic rock hammering associated with the SHHIRP in Kodiak,
Alaska. The City of Kodiak has divided the project into two phases and
is requesting an IHA for each phase. Following NMFS' review of the
application, the City of Kodiak submitted a revised version on January
23, 2026. The application was deemed adequate and complete on February
2, 2026. The City of Kodiak's request is for take of 12 species (15
stocks) of marine mammals, by Level B harassment and, for a subset of 4
species (4 stocks), Level A harassment. Take for these numbers of
species and stocks of marine mammals are the same for both proposed
IHAs. Neither the City of Kodiak nor NMFS expect serious injury or
mortality to result from these activities' and, therefore, IHAs are
appropriate.
Description of Proposed Activity
Overview
St. Herman Harbor in Kodiak, Alaska, provides essential mooring for
both recreational and commercial fishing vessels but much of the
harbor's infrastructure is over 40 years old, deteriorating, and
difficult to navigate. This has led to a loss of mooring capacity and
poses challenges for vessels. To address these issues, the City of
Kodiak is proposing the SHHIRP. This project will remove and replace
the aging infrastructure and dredge the harbor to restore functionality
and improve vessel navigation. The SHHIRP will be completed in two
phases over 2 years, from 2026 to 2028. Phase I is currently scheduled
to begin November 1, 2026, and continue through October 31, 2027. Phase
I construction involves installing a new vessel mooring float and
drive-down dock. These additions will provide extra mooring capacity
and serve as temporary moorage for vessels displaced during Phase II.
Phase II construction would begin after Phase II is complete and is
anticipated to take no more than one year to complete. Phase II
construction will involve removing and replacing the main harbor
infrastructure and will include the removal of 12 existing concrete
headwalks, mainwalks, slip floats, and piles. These will be replaced
with 14 new floats and associated piles in a more efficient
configuration. Phase II will also include dredging approximately 1,900
cubic yards (yd\3\) (1,453 cubic meters (m\3\)) of sediment and bedrock
from the harbor to improve vessel safety. To facilitate removal,
hydraulic rock hammering will be used to fracture bedrock at an
existing shoal.
Activities that have the potential to cause incidental take by
Level A harassment and Level B harassment of marine mammals include
vibratory pile driving and removal, impact pile driving, DTH drilling,
and hydraulic rock hammering to break up bedrock.
Dates and Duration
The City of Kodiak anticipates the project would occur in two
phases over 2 years. The proposed IHAs would be valid for the statutory
maximum of 1 year from the date of effectiveness, and will become
effective upon written notification from the applicant to NMFS, but not
beginning later than 1 year from the date of issuance or extending
beyond 2 years from the date of issuance. The specified activities
could occur any time each year, during daylight hours from 30 minutes
before civil dawn to 30 minutes after civil dusk. Phase I will occur
over 42 non-consecutive construction days, and Phase II will occur over
227 non-consecutive days.
Specified Geographic Region
The City of Kodiak would construct the SHHIRP within St. Herman
Harbor, situated on the western shore of Near Island, Kodiak, Alaska.
As one of Kodiak's 2 primary boat harbors, the facility provides
moorage for more than 328 vessels, ranging from small recreation boats
to large commercial fishing vessels. The benthic substrate within the
harbor consists of sediment and bedrock, including a prominent bedrock
shoal that runs parallel to southern shore of Uski Island along the
Federal Navigation Channel.
Regionally, St Herman Harbor is located on Near Island off the
southeastern coast of Kodiak Island within the Kodiak Archipelago.
Situated in the northwestern Gulf of Alaska, the archipelago is
separated from the Alaska mainland by the Shelikof Strait. This
subarctic marine environment is characterized by high primary
productivity, complex insular geography, and post glacial isolation.
The harbor serves as a primary regional hub for the Kodiak commercial
fishing fleet, which targets Pacific salmon (Oncorhynchus spp.),
Pacific halibut (Hippoglossus stenolepis), various groundfish species
(including walleye pollock and Pacific cod), king crab (Paralithodes
camtschaticus), and Pacific herring (Clupea pallasii).
BILLING CODE 3510-22-P
[[Page 12365]]
[GRAPHIC] [TIFF OMITTED] TN13MR26.000
[GRAPHIC] [TIFF OMITTED] TN13MR26.001
Detailed Description of the Specified Activity
For Phase I of the SHHIRP, in-water work will include the
installation of the slip float and drive down dock. First, 20 24-inch
steel pipe temporary piles would be installed with a vibratory hammer,
but 12 of these temporary piles could be installed by impact driving or
DTH drilling. All temporary piles would be removed with a vibratory
hammer after permanent pile installation. With the temporary piles as
guides, 6 24-inch steel pipe piles and 52 30-inch permanent steel pipe
piles would be installed with a vibratory hammer and then driven to tip
elevation with an impact hammer. After piles reach tip elevation, a DTH
drill would be inserted into each permanent pile, drilled into the
bedrock, and then the shaft would be filled with concrete (table 1).
Phase I would occur over 42 non-consecutive days from November 1, 2026,
through October 31, 2027.
For Phase II of the SHHIRP, 12 existing slip floats, consisting of
656 steel pipe piles between 12 and 20 inches in diameter, would be
removed. These piles would primarily be extracted by direct pull
methods but may be extracted with vibratory methods when direct pull
methods are not practicable. For purposes of the IHA, the City of
Kodiak and NMFS assume all piles would be removed via vibratory hammer.
New structures for Phase II include 14 new slip floats and the
associated support piles. Initially, 80 24-inch steel pipe temporary
piles would be installed with a vibratory hammer which would
[[Page 12366]]
be used to guide permanent piles into place. The permanent support
piles consist of 41 16-inch steel pipe piles, 78 18-inch steel pipe
piles, 22 20-inch steel pipe piles, and 120 24-inch steel pipe piles.
All permanent and the 48 24-inch steel pipe temporary piles would be
installed with vibratory hammering, impact hammering, and DTH drilling
methods similar to Phase I (table 2). Multiple pile driving methods
during Phase I or Phase II of the SHHIRP could occur on the same day
but would not occur simultaneously.
Phase II of the SHHIRP would also include dredging of approximately
1,900 yd\3\ (1,453 m\3\) of sediment and bedrock. Bedrock will be
removed by breaking up rock with a hydraulic hammer (i.e., hoe ram or
breaker). Dredging is not expected to cause take of marine mammals
because dredging activities would not last for sufficient duration to
present the reasonable potential for disruption of behavioral patterns,
do not produce sound with characteristics likely to result in marine
mammal harassment, or some combination of the above, and are thus not
addressed further. However, incidental take could occur from the
hydraulic hammering methods proposed to be used for breaking up bedrock
because the underwater sound generated could reach levels and durations
that may result in behavioral harassment and auditory injury. All
dredged material would be loaded on a barge and disposed of in a quarry
on Near Island. Phase II would occur over 227 non-consecutive days
after Phase I is complete. Due to current funding restraints, the exact
timing of Phase II is currently unknown.
Table 1--SHHIRP Phase I Pile Installation and Removal Summary
----------------------------------------------------------------------------------------------------------------
Time (minutes)
Method Pile size, type Piles/day or (strikes/ Strike rate/ Number of Number of
pile) second piles days
----------------------------------------------------------------------------------------------------------------
Temporary Pile Installation
----------------------------------------------------------------------------------------------------------------
Vibratory........ 24-inch, Round Steel.. 6 20 .............. 20 4
Impact........... 24-inch, Round Steel 6 (300) .............. 12 2
\a\.
DTH.............. 24-inch, Round Steel 6 120 \b\ 10 12 2
\a\.
----------------------------------------------------------------------------------------------------------------
Permanent Pile Installation
----------------------------------------------------------------------------------------------------------------
Vibratory........ 24-inch, Round Steel.. 6 20 .............. 6 1
Impact........... 24-inch, Round Steel.. 6 (1,800) .............. 6 1
DTH.............. 24-inch, Round Steel.. 6 120 \b\ 10 6 1
Vibratory........ 30-inch, Round Steel.. 6 20 .............. 52 9
Impact........... 30-inch, Round Steel.. 6 (1,800) .............. 52 9
DTH.............. 30-inch, Round Steel.. 6 150 \b\ 10 52 9
----------------------------------------------------------------------------------------------------------------
Temporary Pile Removal
----------------------------------------------------------------------------------------------------------------
Vibratory........ 24-inch, Round Steel.. 6 20 .............. 20 4
----------------------------------------------------------------------------------------------------------------
\a\ Indicates 12 of the 20, 24-inch steel temporary piles could be installed with impact driving and/or DTH
drilling methods but would be removed with vibratory methods.
\b\ The City of Kodiak estimates a repetition rate of 10 Hertz (Hz) which falls within the range measured during
other projects in Southeast Alaska (Heyvaert and Reyff, 2021; Denes et. al., 2016) While actual repetition
rate may be higher, for purposes of this analysis, 10 Hz is a reasonable value to apply.
Table 2--SHHIRP Phase II Pile Installation, Removal, and Rock Hammering Summary
----------------------------------------------------------------------------------------------------------------
Time (minutes)
Method Pile size, type Piles/day or (strikes/ Strike rate/ Number of Number of
pile) second piles days
----------------------------------------------------------------------------------------------------------------
Pile Removal
----------------------------------------------------------------------------------------------------------------
Vibratory........ 12-20-inch, Round 20 10 .............. 656 33
Steel.
----------------------------------------------------------------------------------------------------------------
Temporary Pile Installation
----------------------------------------------------------------------------------------------------------------
Vibratory........ 24-inch, Round Steel.. 6 20 .............. 80 13
Impact........... 24-inch, Round Steel.. 6 (300) .............. 48 8
DTH.............. 24-inch, Round Steel.. 6 120 \a\ 10 48 8
----------------------------------------------------------------------------------------------------------------
Permanent Pile Installation
----------------------------------------------------------------------------------------------------------------
Vibratory........ 16-inch, Round Steel.. 6 20 .............. 41 7
Impact........... 16-inch, Round Steel.. 6 (1,800) .............. 41 7
DTH.............. 16-inch, Round Steel.. 6 150 \a\ 10 41 7
Vibratory........ 18-inch, Round Steel.. 6 20 .............. 78 13
Impact........... 18-inch, Round Steel.. 6 (1,800) .............. 78 13
DTH.............. 18-inch, Round Steel.. 6 150 \a\ 10 78 13
Vibratory........ 20-inch, Round Steel.. 6 20 .............. 22 4
Impact........... 20-inch, Round Steel.. 6 (1,800) .............. 22 4
DTH.............. 20-inch, Round Steel.. 6 150 \a\ 10 22 4
Vibratory........ 24-inch, Round Steel.. 6 20 .............. 120 20
Impact........... 24-inch, Round Steel.. 6 (1,800) .............. 120 20
DTH.............. 24-inch, Round Steel.. 6 150 \a\ 10 120 20
----------------------------------------------------------------------------------------------------------------
[[Page 12367]]
Temporary Pile Removal
----------------------------------------------------------------------------------------------------------------
Vibratory........ 24-inch/Round Steel... 6 20 .............. 80 13
----------------------------------------------------------------------------------------------------------------
Rock hammering/Dredging
----------------------------------------------------------------------------------------------------------------
Hydraulic ...................... ........... 250 hours .............. ........... 20
Hammering.
----------------------------------------------------------------------------------------------------------------
\a\ The City of Kodiak estimates a repetition rate of 10 Hz which falls within the range measured during other
projects in Southeast Alaska (Heyvaert and Reyff, 2021; Denes et. al., 2016) While actual repetition rate may
be higher, for purposes of this analysis, 10 Hz is a reasonable value to apply.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; <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 3 lists all species or stocks for which take is expected and
proposed to be authorized for this activity and summarizes information
related to the population or stock, including regulatory status under
the MMPA and Endangered Species Act (ESA) and potential biological
removal (PBR), where known. PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no serious injury or mortality is anticipated or proposed
to be authorized here, PBR and annual serious injury and mortality (M/
SI) from anthropogenic sources are included here as gross indicators of
the status of the species or stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Alaska and Pacific SARs. All values presented in table 3 are
the most recent available at the time of publication (including from
the draft 2024 SARs) and are available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
Table 3--Species \1\ With Estimated Take From the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\2\ abundance survey) \3\ SI \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Artiodactyla--Cetacea--Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
Gray Whale...................... Eschrichtius robustus.. Eastern N Pacific...... -, -, N 26,960 (0.05, 25,849, 801 131
2016).
Family Balaenopteridae (rorquals):
Fin Whale....................... Balaenoptera physalus.. Northeast Pacific...... E, D, Y UND (UND, UND, 2013) UND 0.6
\5\.
Humpback Whale.................. Megaptera novaeangliae. Hawai[revaps]i......... -, -, N 11,278 (0.56, 7,265, 127 27.09
2020) \6\.
Humpback Whale.................. Megaptera novaeangliae. Mexico-North Pacific... T, D, Y N/A (N/A, N/A, 2006) UND 0.57
\7\.
Humpback Whale.................. Megaptera novaeangliae. Western N Pacific...... E, D, Y 1,084 (0.088, 1,007, 3.4 \8\ 5.82
2006).
Minke Whale..................... Balaenoptera AK..................... .................. N/A (N/A, N/A, N/A) UND 0
acutorostrata. \9\.
Family Delphinidae:
Killer Whale.................... Orcinus orca........... Eastern North Pacific -, -, N 1,920 (N/A, 1,920, 19 1.3
Alaska Resident. 2019) \10\.
Killer Whale.................... Orcinus orca........... Eastern North Pacific -, -, N 587 (N/A, 587, 2012) 5.9 0.8
Gulf of Alaska, \10\.
Aleutian Islands and
Bering Sea Transient.
Pacific White-Sided Dolphin..... Lagenorhynchus N Pacific.............. -, -, N 26,880 (N/A, N/A, UND 0
obliquidens. 1990).
Family Phocoenidae (porpoises):
Dall's Porpoise................. Phocoenoides dalli..... AK..................... -, -, N UND (UND, UND, 2015) UND 37
\5\.
Harbor Porpoise................. Phocoena Phocoena...... Gulf of Alaska......... -, -, Y 31,046 (0.21, N/A, UND 72
1998).
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 12368]]
Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
sea lions):
Northern Fur Seal............... Callorhinus ursinus.... Eastern Pacific........ -, D, Y 626,618 (0.2, 530,376, 11,403 373
2019) \11\.
Steller Sea Lion................ Eumetopias jubatus..... Western................ E, D, Y 49,837 (N/A, 49,837, 299 267
2022) \12\.
Family Phocidae (earless seals):
Harbor Seal..................... Phoca vitulina......... South Kodiak........... -, -, N 26,448 (N/A, 22,351, 939 127
2017).
Northern Elephant Seal.......... Mirounga angustirostris CA Breeding............ -, -, N 187,386 (N/A, 85,369, 5,122 13.7
2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR, or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\3\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region</a>. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable. N/A
indicates data are unknown. UND (undetermined) PBR indicates data are available to calculate a PBR level, but a determination has been made that
calculating a PBR level using those data is inappropriate (see the SAR for details).
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
\5\ The best available abundance estimate for this stock is not considered representative of the entire stock as surveys were limited to a small portion
of the stock's range. Based upon this estimate and Nmin, the PBR value is likely negatively biased for the entire stock.
\6\ New SAR in 2022 following North Pacific humpback whale stock structure changes.
\7\ Abundance estimates are based upon data collected more than 8 years ago and, therefore, current estimates are considered unknown.
\8\ PBR in U.S. waters = 0.2, M/SI in U.S. waters = 0.06.
\9\ Reliable population estimates are not available for this stock. Please see Friday et al. (2013) and Zerbini et al. (2006) for additional information
on numbers of minke whales in Alaska.
\10\ Nest is based upon counts of individuals identified from photo-ID catalogs.
\11\ Survey years = Sea Lion Rock--2014; St. Paul and St. George Is--2014, 2016, 2018; Bogoslof Is.--2015, 2019.
\12\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the U.S.
only. The overall Nmin is 73,211 and overall PBR is 439.
As indicated above, all 12 species (with 15 managed stocks) in
table 3 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. All species that could
potentially occur in the proposed action area are included in table 3
of the IHA application. While North Pacific right whales, goose-beaked
whales, and sperm whales have been reported in waters off Kodiak
Island, the temporal and/or spatial occurrence of these species is such
that take is not expected to occur, and they are not discussed further
beyond the explanation provided here. North Pacific right whales goose-
beaked whales, and sperm whales prefer deep, pelagic waters and are all
considered to be rare (no sightings in recent years) within the project
area. 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 may be found in Kodiak, AK.
However, northern sea otters are managed by the U.S. Fish and Wildlife
Service and are not considered further in this document.
Gray Whale
Gray whales are found most regularly throughout the North Pacific
Ocean in shallow coastal waters, occasionally crossing deep waters
during migration (NOAA Fisheries, 2023). Two distinct population
segments (DPS) of gray whale occur in the north Pacific: the Eastern
North Pacific DPS (delisted) and the Western North Pacific DPS
(Endangered). The Eastern North Pacific DPS is more likely to occur
near Kodiak Archipelago.
Some scientific and opportunistic data exists on gray whale
presence near the project area. During aerial surveys in waters
surrounding Kodiak Island conducted between 1999 and 2005 for Sea Grant
Gulf Apex Predator-Prey Project, gray whales were primarily observed
near Ugak Bay, approximately 79 (km) (49 mi) south of the project area
(Sea Grant Alaska, 2012). Smaller numbers of gray whales were also
observed approximately 8 km (5 mi) to the southeast of the project
site, in Chiniak Bay (Sea Grant Alaska, 2012). During a ferry terminal
reconstruction and dock improvement project completed in Kodiak Harbor,
approximately 1.5 km (1 m) north of the site, monitors observed marine
mammals during construction activities on 110 days between November 10,
2015, and June 16, 2016 (ABR, Inc., 2016). No gray whales were observed
during that time.
Wild et al., (2023) identified a Gray Whale Migratory Route
Biologically Important Area (BIA) that intersects with a small portion
of the project area during the months of January, March, April, May,
November and December, with an importance score of 1 (the lowest of
three possible scores (1, 2, or 3), reflecting an intensity score of 2
(indicating an area of moderate comparative significance) and a data
support score of 1 (lower relative confidence in the available
supporting data). Wild et al., (2023) also identified the waters to the
southeast of Kodiak Island as a BIA for gray whales for feeding during
June through August, April and May, and September and October. However,
this feeding BIA does not intersect with the project area.
Gray whales are typically solitary or travel in small groups (Frost
and Karpovich, 2008) and are considered rare in the project area. While
the shallow waters of St. Herman Harbor do not represent preferred
habitat for large whales, given confirmed gray whale sightings in
Chiniak Bay, and that the project area overlaps with a small portion of
the migratory BIA for this species, gray whales could occur within the
project area.
[[Page 12369]]
Fin Whale
Fin whales from the Northeast Pacific stock (ESA-Endangered) are
known to occur within the waters surrounding Kodiak Island. During
vessel transect surveys conducted along Western Alaska and the central
Aleutian Islands between 2001 and 2003, fin whales were observed
throughout a broad range, from the Kenai Peninsula to the Shumagin
Islands. Notably, high concentrations were found in the coastal waters
surrounding Kodiak Island (Zerbini et al., 2006). This finding is
corroborated by aerial surveys conducted from 1999 to 2005, which also
indicate that some of the highest regional concentrations of fin whales
occur in the Chiniak Trough South of Afognak Island and north of Kodiak
Island in the Shelikof Strait (Sea Grant Alaska, 2012). These areas
have deeper bathymetry than the project area and provide fin whales
with direct access to open waters they typically inhabit.
Wild et al. (2023) identified the waters around Kodiak Island
(including the proposed project area) as a BIA for fin whales for
feeding during the months of June through September, with an importance
score of 1 (the lowest of three possible scores (1, 2, or 3),
reflecting an intensity score of 1 (indicating an area of lower
comparative significance) and a data support score of 2 (moderate
relative confidence in the available supporting data).
Fin whales occur year-round near Kodiak Island, with peak sightings
in spring and summer (Wynne and Witteveen, 2005). While the shallow-
water characteristics of the project area are not consistent with fin
whales' preferred habitat, they have recently been documented northwest
of the action area in Marmot Bay (Happywhale, 2025). Additionally, fin
whales are known to occur in coastal regions within the broader Gulf of
Alaska, and a small portion of the feeding BIA overlaps with the
project area. Therefore, fin whales have the potential to enter
ensonified areas during construction for the SHHIRP.
Humpback Whale
Humpback whales are one of the most common marine mammal species in
the Gulf of Alaska. In the project area, the Hawaii stock is the most
predominant and accounts for approximately 89 percent of humpbacks
occurring in the Gulf of Alaska. The Mexico-North Pacific stock is
expected to represent approximately 11 percent, while the Western North
Pacific stock represents less than 1 percent of humpbacks observed
within the project areas (Wade, 2021).
Wild et al. (2023) identified the waters around and to the East of
Kodiak Island (including the proposed project area) as a BIA for
humpback whales for feeding during the months of May through September,
with an importance score of 1 (the lowest of three possible scores (1,
2, or 3), reflecting an intensity score of 2 (indicating an area of
moderate comparative significance) and a data support score of 1 (lower
relative confidence in the available supporting data).
Humpback whales are common in the project area year-round with
peaks during the spring and fall. They often feed in shallower waters
closer to the coastline and have been documented in shallow coastal
waters near Kodiak Island on some years (Baraff 2006; ABR, Inc. et al.,
2016). For example, during construction for the Kodiak Ferry Terminal
and Dock Improvements Project from November 10, 2015, and June 16,
2016, one humpback whale was documented in the area in Kodiak, AK (ABR,
Inc. et al., 2016). Therefore, humpback whales have the potential to
enter ensonified areas during project construction.
Minke Whale
Minke whales are found throughout the northern hemisphere in polar,
temperate, and tropical waters. The International Whaling Commission
has identified three minke whale stocks in the North Pacific: one near
the Sea of Japan, a second in the rest of the western Pacific (west of
180[deg] W), and a third, less concentrated stock throughout the
eastern Pacific. NMFS further splits this third stock between Alaska
whales and resident whales of California, Oregon, and Washington (Muto
et al., 2018). Minke whales are found in all Alaska waters; however, no
population estimates are currently available for the Alaska stock.
Minke whale sightings are rare in the Gulf of Alaska, including
near Kodiak. During the Gulf of Alaska Line-Transect Survey (GOALS) II,
so few individuals were sighted in the central Gulf of Alaska that no
abundance estimates could be computed (Rone et al., 2017). Across 110
monitoring days between November 10, 2015, and June 16, 2016, no minke
whales were observed during the ferry terminal reconstruction and dock
improvement project in Kodiak Harbor (ABR, Inc. et al., 2016). However,
a few observations of minke whales were recorded in nearshore waters
near Kodiak Island during line transect surveys conducted in central
Alaska coastal waters (Zerbini et al., 2006). They are often observed
in groups of two or three (Guerrero, 2008).
Killer Whale
Killer whales have been observed in all oceans, but the highest
densities occur in colder and more productive waters found at high
latitudes. Killer whales occur along the entire coast of Alaska (Braham
and Dahlheim, 1982), inland waterways of British Columbia and
Washington (Bigg et al., 1990), and along the outer coasts of
Washington, Oregon, and California (Green et al., 1992; Barlow, 1995,
1997; Forney et al., 1995). Resident killer whales in the eastern North
Pacific primarily feed on salmonids, and show distinct preference for
Chinook salmon, whereas transient killer whales primarily hunt and feed
on marine mammals, including harbor seals, Dall's porpoise, harbor
porpoises, and sea lions (Muto et al., 2020). Eight stocks of killer
whales are recognized within the Pacific U.S. Exclusive Economic Zone
(Muto et al., 2020).
The fish-eating Alaska resident stock of killer whale most commonly
occurs in nearshore waters near the project area throughout the year.
However, transient killer whales are also known to frequent the Kodiak
Harbor area to hunt Steller sea lions during the months of February
through May (UAF, 2015). During the Kodiak Ferry Terminal Improvements
project, four pods of killer whales were observed in groups ranging
from three to seven individuals across 110 days of monitoring between
November 10, 2015, and June 16, 2016 (ABR, Inc. et al., 2016).
Therefore, it is expected that killer whales may occur in the project
area during the proposed activities.
Pacific White-Sided Dolphin
The Pacific white-sided dolphin is found in temperate waters of the
North Pacific from the southern Gulf of California to Alaska. Across
the North Pacific, it appears to occur between 33[deg] N and 47[deg] N
(Young et al., 2023; Waite and Shelden, 2018). In the eastern North
Pacific Ocean, the Pacific white-sided dolphin is one of the most
common cetacean species, occurring primarily in shelf and slope waters
(Green et al., 1993; Barlow 2003, 2010). During winter, this species is
most abundant in California slope and offshore areas; as northern
waters begin to warm in the spring, it appears to move north to slope
and offshore waters off Oregon/Washington (Green et al., 1992, 1993;
Forney et al., 1995; Buchanan et al., 2001; Barlow, 2003). White-sided
are highly gregarious and typically observed in groups from 10 to 100
individuals but groups can range into the thousands (Clark, 2008b;
NMFS, 2022).
[[Page 12370]]
In the Gulf of Alaska, specifically within the project area, only
the North Pacific stock is expected to occur during construction. In
2015, NOAA Fisheries Southwest Fisheries Science Center (SWFSC) in
collaboration with NOAA Fisheries Alaska Fisheries Science Center,
undertook a robust whale survey along the U.S. and Canadian Pacific
coast (Weller, 2021). During the SWFSC survey several Pacific white-
sided dolphins were sighted south of the project area between Chiniak
and Sitkalidak Island (Weller, 2021). Across 110 monitoring days
between November 10, 2015, and June 16, 2016, no Pacific white-sided
dolphins were observed during the ferry terminal reconstruction and
dock improvement project in Kodiak Harbor (ABR, Inc. et al., 2016).
Given their preference for deeper, pelagic waters, Pacific white-sided
dolphins have the potential to occur near St. Herman Harbor, which is
situated close to the edge of the continental shelf.
Dall's Porpoise
Dall's porpoise is found in temperate to subarctic waters of the
North Pacific and adjacent seas (Jefferson et al., 2015). It is widely
distributed across the North Pacific over the continental shelf and
slope waters, and over deep (greater than 2,500 m) oceanic waters
(Friday et al., 2012; Friday et al., 2013). It is probably the most
abundant small cetacean in the North Pacific Ocean, and its abundance
changes seasonally, likely in relation to water temperature (Becker,
2007).
During three surveys from 2009 through 2015, Dall's porpoises were
one of the most frequently observed marine mammal species in the Gulf
of Alaska including inshore and continental shelf waters (Rone et al.,
2017). Similarly, in a survey conducted in 2012, one group of three
Dall's porpoises were documented in 66 meters along the continental
slope of Kodiak Island (Suzuki et al., 2016). For the 110 days of
monitoring from November 10, 2015, through June 16, 2016, no Dall's
porpoises were observed during the Kodiak Ferry Terminal Improvements
Project (ABR, Inc. et al., 2016). Since Dall's Porpoises are known to
occur near Kodiak Island, they may occur in the project area during the
proposed activities for the SHHIRP.
Harbor Porpoise
There are six harbor porpoise stocks in Alaska: the Bering Sea
stock occurs throughout the Aleutian Islands and all waters north of
Unimak Pass; the Gulf of Alaska stock occurs from Cape Suckling to
Unimak Pass; the Northern Southeast Alaska Inland Waters stock includes
Cross Sound, Glacier Bay, Icy Strait, Chatham Strait, Frederick Sound,
Stephens Passage, Lynn Canal, and adjacent inlets; the Southern
Southeast Alaska Inland Waters stock encompasses Sumner Strait,
including areas around Wrangell and Zarembo Islands, Clarence Strait,
and adjacent inlets and channels within the inland waters of Southeast
Alaska north-northeast of Dixon Entrance; and the Yakutat/Southeast
Alaska Offshore Waters stock includes offshore habitats in the Gulf of
Alaska west of the Southeast Alaska inland waters and the areas around
Yakutat Bay (Young et al., 2023). Only harbor porpoise from the Gulf of
Alaska stock is expected to be encountered in the project area.
During the 1992 National Marine Mammal Laboratory's Harbor Porpoise
Aerial Survey conducted around Kodiak Island, dozens of harbor
porpoises were spotted, with one documentation occurring within the
action area (Dahlheim et al., 2000). Group sizes reported during the
same survey averaged 1.41 individuals (Dahlheim et al., 2000). A total
of six harbor porpoise were documented across 110 monitoring days
between November 10, 2015, and June 16, 2016, during the ferry terminal
reconstruction and dock improvement project in Kodiak Harbor (ABR, Inc.
et al., 2016). The largest group size was two. Considering that harbor
porpoises are known to occur around Kodiak Island and were observed
during the Kodiak Ferry Terminal Improvements Project, they may occur
in the project area during construction for the SHHIRP.
Northern Elephant Seal
Northern elephant seals breed and give birth in California (U.S.)
and Baja California (Mexico), primarily on offshore islands (Stewart et
al., 1994), from December to March (NMFS 2015). Males migrate to the
Gulf of Alaska and western Aleutian Islands along the continental shelf
to feed on benthic prey, while females migrate to pelagic areas in the
Gulf of Alaska and the central North Pacific Ocean to feed on pelagic
prey (Le Boeuf et al., 2000). Adults return to land between March and
August to molt, with males returning later than females. Adults return
to their feeding areas again between their spring/summer molting and
their winter breeding seasons (Carretta et al., 2015).
Northern elephant seals are uncommon in project area and are rarely
seen as far north as Kodiak Island. However, the Sun'aq Tribe of Kodiak
indicated that a northern elephant seal was observed near the project
area for about 10 days in 2023.
Northern Fur Seal
Northern fur seals occur from southern California north to the
Bering Sea and west to the Sea of Okhotsk and Honshu Island, Japan.
During the summer breeding season, most of the worldwide population is
found on the Pribilof Islands (St. Paul Island and St. George Island)
in the southern Bering Sea, with the remaining animals on rookeries in
Russia, on Bogoslof Island in the southern Bering Sea, on San Miguel
Island off southern California, and on the Farallon Islands off central
California (Muto et al., 2022). Northern fur seals feed on a variety of
prey including squid, walleye pollock (Gadus chalcogrammus), Pacific
hearing (Clupea pallasii), and capelin (Mallotus villosus) (Gomez et
al., 2015). Breeding and important haulouts areas are not expected to
spatially overlap with the project area.
Northern fur seals inhabit deep pelagic waters for most of their
lives. The closest documented occurrence occurred approximately 60
miles west of the project area (Hobbs, 2004). Across 110 monitoring
days between November 10, 2015, and June 16, 2016, no northern fur
seals were observed during the ferry terminal reconstruction and dock
improvement project in Kodiak Harbor (ABR, Inc. et al., 2016).
Steller Sea Lion
The Steller sea lion's range extends across the North Pacific Rim
from northern Japan to California with areas of abundance in the Gulf
of Alaska and Aleutian Islands (Muto et al., 2020). In 1997, based on
demographic and genetic dissimilarities, NMFS identified two DPSs of
Steller sea lions under the ESA: a western DPS (western stock) and an
eastern DPS (eastern stock). The western DPS breeds on rookeries
located west of 144[deg] W in Alaska and Russia, whereas the eastern
DPS breeds on rookeries in southeast Alaska through California. Steller
sea lions in the project area are anticipated to be part of the western
DPS (western stock; Hastings et al., 2020).
Steller sea lions do not follow traditional migration patterns but
will move from offshore rookeries in the summer to more protected
haulouts closer to shore in the winter. They use rookeries and haulouts
as resting spots as they follow prey movements and take foraging trips
for days, usually within a few miles of their rookery or haulout. They
are generalist marine predators and opportunistic feeders based on
seasonal abundance and location of
[[Page 12371]]
prey. Steller sea lions forage in nearshore as well as offshore areas,
following prey resources.
Steller sea lion critical habitat in western Alaska includes a 20
nautical mile buffer around all major haulouts and rookeries as well as
associated terrestrial, air and aquatic zones, and three large offshore
foraging areas. The project area would overlap with the aquatic zone of
Steller sea lion haulouts designated as critical habitat.
During aerial surveys in 2007 and 2008, Steller sea lions were
regularly documented on haulouts around Kodiak Island, AK (Sea Grant
Alaska, 2012). Similarly, during the Kodiak Island Ferry Terminal
Improvements Project, 5,111 observations of individual Steller sea
lions occurred across 110 monitoring days between November 10, 2015,
and June 16, 2016 (ABR, Inc. et al., 2016). Steller sea lions were most
commonly observed hauled out on the Dog Bay Float, and the number of
individuals hauled out ranged between 20 to over 100 individuals when
counts occurred bi-weekly. Due to the presence of Steller sea lions on
the Dog Bay Float and the close proximity of the SHHIRP to this float
(200 m for Phase I and 300 m for Phase II), Steller sea lions are
expected to occur in the project area on a daily basis throughout
project activities.
Sightings of Steller sea lions in St. Herman Harbor are common, and
animals have been observed hauled out on the Dog Bay Float all months
except June and July. The Sun'aq Tribe of Kodiak conducted single day
counts of Steller sea lions hauled out at the Dog Bay Float once per
month during March, May, June, and September 2023; January, April, May,
and October 2024; and March, May, July, and September 2025 (Van Daele,
pers. comm., 2025). The maximum number of Steller sea lions observed in
one day was 226 in May 2025, the minimum was 0 in June 2023 and July
2025. Throughout these float counts, individual Steller sea lions with
brands or scars were re-sighted multiple times, suggesting that animals
that use the float consists of a resident group of approximately 300
animals. Therefore, this resident group of Steller sea lions is
expected to occur in the project area daily during construction for the
SHHIRP.
Harbor Seal
Harbor seals are common in the coastal and inside waters of the
project area. Harbor seals in Alaska are typically non-migratory with
local movements attributed to factors such as prey availability,
weather, and reproduction (Scheffer and Slipp, 1944; Fisher, 1952; Bigg
1969, 1981; Hastings et al., 2004). Harbor seals haul out of the water
periodically to rest, give birth, and nurse their pups. There are 12
stocks of harbor seals in Alaska but only the South Kodiak stock is
expected to occur in the project area.
Limited data exists for harbor seal in the project area, but
animals have been documented during marine mammal monitoring for other
coastal construction projects between the months of November and June
(ABR, Inc. et al., 2016; Pacific Seafood, 2025). During Construction
for the Kodiak Ferry Terminal Improvements Project, 13 harbor seals
were observed over 110 monitoring days between November 10, 2015, and
June 16, 2016 (ABR, Inc. et al., 2016). Considering that harbor seals
are known to occur around Kodiak Island and were observed during the
Kodiak Ferry Terminal Improvements Project, they may occur in the
project area during construction for the SHHIRP.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
(2007, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). Generalized hearing ranges were
chosen based on the ~65 decibel (dB) threshold from composite
audiograms, previous analyses in NMFS (2018), and/or data from Southall
et al. (2007) and Southall et al. (2019). We note that the names of two
hearing groups and the generalized hearing ranges of all marine mammal
hearing groups have been recently updated (NMFS, 2024) as reflected
below in table 4.
Table 4--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 (dolphins, 150 Hz to 160 kHz.
toothed whales, beaked whales, bottlenose
whales).
Very High-frequency (VHF) cetaceans (true 200 Hz to 165 kHz.
porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus cruciger &
L. australis).
Phocid pinnipeds (PW) (underwater) (true 40 Hz to 90 kHz.
seals).
Otariid pinnipeds (OW) (underwater) (sea 60 Hz to 68 kHz.
lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges may not be as broad. Generalized hearing range
chosen based on ~65 dB threshold from composite audiogram, previous
analysis in NMFS 2018, and/or data from Southall et al. (2007, 2019).
Additionally, animals are able to detect very loud sounds above and
below that ``generalized'' hearing range.
For more details concerning these groups and associated frequency
ranges, please see NMFS (2024) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take of Marine Mammals section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section and the Proposed Mitigation section 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
[[Page 12372]]
stock through effects on annual rates of recruitment or survival.
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far (American National Standards Institute
(ANSI), 1995). The sound level of an area is defined by the total
acoustic energy being generated by known and unknown sources. These
sources may include physical (e.g., waves, wind, precipitation,
earthquakes, ice, atmospheric sound), biological (e.g., sounds produced
by marine mammals, fish, and invertebrates), and anthropogenic sound
(e.g., vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activities may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
In-water construction associated with the proposed project would
include vibratory and impact pile driving, DTH drilling, vibratory pile
removal, and hydraulic rock hammering. The sounds produced by these
activities fall into one of two general sound types: impulsive and non-
impulsive (defined below). The distinction between these two sound
types is important because they have differing potential to cause
physical effects, particularly with regard to hearing (e.g., Ward, 1997
in Southall et al., 2007). Please see Southall et al. (2007) for an in-
depth discussion of these concepts.
Impulsive sound sources (e.g., explosions, gunshots, sonic booms,
impact pile driving) are brief (typically considered to be less than 1
second), broadband, atonal transients (ANSI, 1986; National Institute
for Occupational Safety and Health (NIOSH), 1998; International
Organization for Standardization (ISO) 2003; ANSI, 2005; NMFS, 2018)
and occur either as isolated events or repeated in some succession.
Impulsive sounds are all characterized by a relatively rapid rise from
ambient pressure to a maximal pressure value followed by a rapid decay
period that may include a period of diminishing, oscillating maximal
and minimal pressures, and generally have an increased capacity to
induce physical injury as compared with sounds that lack these
features.
Non-impulsive sounds (e.g., aircraft, machinery operations such as
drilling or dredging, vibratory pile driving, and active sonar systems)
can be broadband, narrowband or tonal, brief or prolonged (continuous
or intermittent), and typically do not have the high peak sound
pressure with rapid rise/decay time that impulsive sounds do (ANSI,
1995; NIOSH, 1998; NMFS, 2018). The distinction between these two sound
types is important because they have differing potential to cause
physical effects, particularly with regard to hearing (e.g., Ward 1997
in Southall et al., 2007).
The SHHIRP projects would include the use of impact, vibratory, and
DTH hammers for pile installation and vibratory hammers for pile
removal. Impact hammers operate by repeatedly dropping a heavy piston
onto a pile to drive the pile into the substrate. Sound generated by
impact hammers is characterized by rapid rise times and high peak
levels, a potentially injurious combination (Hastings and Popper,
2005). Vibratory hammers install piles by vibrating them and allowing
the weight of the hammer to push them into the sediment and produce
significantly less sound than impact hammers. Peak sound pressure
levels (SPLs) may be 180 dB or greater, but are generally 10 to 20 dB
lower than SPLs generated during impact pile driving of the same-sized
pile (Oestman et al., 2009). Rise time is slower, reducing the
probability and severity of injury, and sound energy is distributed
over a greater amount of time (Nedwell and Edwards, 2002; Carlson et
al., 2005).
A DTH hammer is essentially a drill bit that drills through the
bedrock using a rotating function like a normal drill, in concert with
a hammering mechanism operated by a pneumatic (or sometimes hydraulic)
component integrated into the DTH hammer to increase speed of progress
through the substrate (i.e., it is similar to a ``hammer drill'' hand
tool). The sounds produced by DTH systems contain both a continuous,
non-impulsive component from the drilling action and an impulsive
component from the hammering effect. Therefore, NMFS treats DTH systems
as both impulsive (for estimating Level A harassment zones) and non-
impulsive (for estimating Level B harassment zones) sound source types
simultaneously.
Hydraulic rock hammers (i.e., hoe rams) are impact devices that
would be used to break up bedrock prior dredging. Hydraulic rock
hammers operate by using rock hammer operates by using a chisel-like
hammer to rapidly strike an exposed surface to break it up into smaller
pieces that will be removed by a clamshell dredge or bucket excavator,
as appropriate. Few data exist regarding the underwater sounds produced
by rock hammers. Data reported by Escude (2012), however, suggest that
the sounds produced by hoe rams are comparable to impact hammers.
Therefore, for the purposes of this analysis, it is assumed that
hydraulic rock hammers act as an impulsive source characterized by
rapid rise times and high peak levels.
The likely or possible impacts of the City of Kodiak'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, any
impacts to marine mammals are expected to primarily be acoustic in
nature.
Potential Effects of Underwater Sound on Marine Mammals
The introduction of anthropogenic noise into the aquatic
environment from pile driving and removal, DTH drilling, and hydraulic
rock hammering is the means by which marine mammals may be harassed
from the City of Kodiak's specified activities. Anthropogenic sounds
cover a broad range of frequencies and sound levels and can have a
range of highly variable impacts on marine life from none or minor to
potentially severe responses depending on received levels, duration of
exposure, behavioral context, and various other factors. Broadly,
underwater sound from active acoustic sources, such as those in the
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; Gordon et al., 2003; Nowacek et al.,
[[Page 12373]]
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
use of pile driving hammers (impact, vibratory, and DTH) are reasonably
likely to result in such effects (see below for further discussion).
Potential effects from impulsive sound sources can range in severity
from effects such as behavioral disturbance or tactile perception to
physical discomfort, slight injury of the internal organs and the
auditory system, or mortality (Yelverton et al., 1973). Non-auditory
physiological effects or injuries that theoretically might occur in
marine mammals exposed to high level underwater sound or as a secondary
effect of extreme behavioral reactions (e.g., change in dive profile as
a result of an avoidance reaction) caused by exposure to sound include
neurological effects, bubble formation, resonance effects, and other
types of organ or tissue damage (Cox et al., 2006; Southall et al.,
2007; Zimmer and Tyack, 2007; Tal et al., 2015). The Project activities
considered here do not involve the use of devices such as explosives or
mid-frequency tactical sonar that are associated with these types of
effects.
In general, animals exposed to natural or anthropogenic sound may
experience physical and psychological effects, ranging in magnitude
from none to severe (Southall et al., 2007, 2019). Exposure to
anthropogenic noise has the potential to result in auditory threshold
shifts and behavioral reactions (e.g., avoidance, temporary cessation
of foraging and vocalizing, changes in dive behavior). It can also lead
to non-observable physiological responses, such an increase in stress
hormones. Additional noise in a marine mammal's habitat can mask
acoustic cues used by marine mammals to carry out daily functions, such
as communication and predator and prey detection.
The 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, will occur
almost exclusively for noise within an animal's hearing range. We
describe below the specific manifestations of acoustic effects that may
occur based on the activities proposed by the City of Kodiak.
Richardson et al. (1995) described zones of increasing intensity of
effect that might be expected to occur in relation to distance from a
source and 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
with the area where the signal is audible to the animal and of
sufficient intensity to elicit behavioral or physiological
responsiveness. The third is a zone within which, for signals of high
intensity, the received level is sufficient to potentially cause
discomfort or tissue damage to auditory or other systems. Overlaying
these zones to a certain extent is the area within which masking (i.e.,
when a sound interferes with or masks the ability of an animal to
detect a signal of interest that is above the absolute hearing
threshold) may occur; the masking zone may be highly variable in size.
Below, we provide additional detail regarding potential impacts on
marine mammals and their habitat from noise in general, starting with
hearing impairment, as well as from the specific activities the City of
Kodiak plans to conduct, to the degree it is available.
Auditory Injury (AUD INJ)--NMFS defines auditory injury as ``damage
to the inner ear that can result in destruction of tissue . . . which
may or may not result in permanent threshold shift (PTS)'' (NMFS,
2024). AUD INJ may or may not result in a permanent threshold shift
(PTS). NMFS defines PTS as a permanent, irreversible increase in the
threshold of audibility at a specified frequency or portion of an
individual's hearing range above a previously established reference
level ANSI, 1995; Yost, 2007). A variety of terrestrial and marine
mammal studies (e.g., Ward et al., 1958; Ward et al., 1959; Ward, 1960;
Miller et al., 1963; Kryter et al., 1966; Finneran et al., 2007;
Kastelein et al., 2013) indicate that threshold shifts of up to 40 to
50 dB (measured a few minutes after exposure) may be induced without
resulting in PTS. Therefore, an exposure producing an initial threshold
shift of 40 dB is considered the minimum upper limit for a reversible
threshold shift and any additional exposure could result in some PTS.
Thus, NMFS has set the PTS onset as a threshold shift of 40 dB.
However, after sound exposure ceases or between successive sound
exposures, the potential for recovery from hearing loss exists. Thus,
because a threshold shift is measured a few minutes after noise
exposure does not mean that those initial shifts are persistent (i.e.,
no recovery). When initial threshold shifts fully recover back to
baseline hearing levels, these are considered TTS. PTS indicates that
there is not full recovery back to baseline hearing levels, but it does
not mean that there is no recovery. Rather PTS indicates that there is
incomplete recovery. Recovery is dependent on the initial threshold
shift amount, the frequency where the shift occurred, temporal pattern
of exposure (e.g., exposure duration; continuous vs. intermittent or
interrupted exposure), and physiological mechanisms associated with the
shift (e.g., mechanical vs. metabolic, recovery processes within
cochlea). Since recovery is complicated, our current AUD INJ onset
criteria do not account for the potential for recovery.
Temporary Threshold Shift (TTS)--TTS is a temporary, reversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS, 2018). Based on data from cetacean TTS
measurements (Southall et al., 2007, 2019), a TTS of 6 dB is considered
the minimum TS clearly larger than any day-to-day or session-to-session
variation in a subject's normal hearing ability (Schlundt et al., 2000;
Finneran et al, 2000, 2002). As described in Finneran (2015), marine
mammal studies have shown the amount of TTS increases with cumulative
sound exposure level (SELcum) in an accelerating fashion: At low
exposures with lower SELcum, the amount of TTS is typically small and
the growth curves have shallow slopes. At exposures with higher SELcum,
the growth curves become steeper and approach linear relationships with
the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in auditory
masking, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient
[[Page 12374]]
noise is lower and there are not as many competing sounds present.
Alternatively, a larger amount and longer duration of TTS sustained
during a time when communication is critical for successful mother/calf
interactions could have more serious impacts. We note that reduced
hearing sensitivity as a simple function of aging has been observed in
marine mammals, as well as humans and other taxa (Southall et al.,
2007), so we can infer that strategies exist for coping with this
condition to some degree, though likely not without cost.
Many studies have examined noise-induced hearing loss in marine
mammals (see Finneran (2015) and Southall et al. (2019) for summaries).
TTS is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter, 2013). While experiencing TTS, the hearing
threshold rises, and a sound must be at a higher level in order to be
heard. In terrestrial and marine mammals, TTS can last from minutes or
hours to days (in cases of strong TTS). In many cases, hearing
sensitivity recovers rapidly after exposure to the sound ends. For
pinnipeds in water, measurements of TTS are limited to harbor seals,
elephant seals (Mirounga angustirostris), bearded seals (Erignathus
barbatus) and California sea lions (Zalophus californianus) (Kastak et
al., 1999, 2007; Kastelein et al., 2019b, 2019c, 2021, 2022a, 2022b;
Reichmuth et al., 2019; Sills et al., 2020). These studies examined
hearing thresholds measured in marine mammals before and after exposure
to intense or long-duration sound exposures. The difference between the
pre-exposure and post-exposure thresholds can be used to determine the
amount of TS at various post-exposure times.
The amount and onset of TTS depends on the exposure frequency.
Sounds at low frequencies, well below the region of best sensitivity
for a species or hearing group, are less hazardous than those at higher
frequencies, near the region of best sensitivity (Finneran and
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are
higher compared to those in the region of best sensitivity (i.e., a low
frequency noise would need to be louder to cause TTS onset when TTS
exposure level is higher), as shown for harbor porpoises and harbor
seals (Kastelein et al., 2019a, 2019c). Note that in general, harbor
seals have a lower TTS onset than other measured pinniped species
(Finneran, 2015). In addition, TTS can accumulate across multiple
exposures, but the resulting TTS will be less than the TTS from a
single, continuous exposure with the same SEL (Mooney et al., 2009;
Finneran et al., 2010; Kastelein et al., 2014, 2015). This means that
TTS predictions based on the total, SELcum will overestimate the amount
of TTS from intermittent exposures, such as sonars and impulsive
sources. Nachtigall et al. (2018) describes measurements of hearing
sensitivity of multiple odontocete species (i.e., 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). Additionally, the existing marine mammal TTS data come from
a limited number of individuals within these species.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals, but such relationships are assumed to be similar to
those in humans and other terrestrial mammals. PTS typically occurs at
exposure levels at least several dBs above that inducing mild TTS
(e.g., a 40-dB TS approximates PTS onset (Kryter et al., 1966; Miller,
1974)), while a 6-dB TS approximates TTS onset (Southall et al., 2007,
2019). Based on data from terrestrial mammals, a precautionary
assumption is that the PTS thresholds for impulsive sounds (such as
impact pile driving pulses as received close to the source) are at
least 6 dB higher than the TTS threshold on a peak-pressure basis and
PTS SELcum thresholds are 15 to 20 dB higher than TTS SELcum thresholds
(Southall et al., 2007, 2019).
Construction at SHHIRP would require a combination impact and
vibratory pile driving and removal, DTH drilling, and hydraulic rock
hammering. Construction for each phase of the SHHIRP would be
independent both spatially and temporally. Only one method of pile
installation, pile removal or hydraulic rock hammering would occur at a
time, although multiple methods may be used in the same day. Proposed
construction activities for each phase are not expected to be constant
and pauses in the activities producing sound are likely to occur each
day. Given these pauses and that many marine mammals are likely moving
through the project areas and not remaining for extended periods of
time, the potential for TS declines. For Steller sea lions, animals are
expected to remain in project area, particularly around the Dog Bay
float. Animals swimming with heads underwater would be exposed to pile
driving noise throughout a day on multiple days, increasing risk of TS.
However, we also expect these individuals to remain out of the water on
the float for extended durations which reduces risk of TS.
Behavioral Harassment--Exposure to noise from pile installation,
pile removal, DTH drilling, and rock hammering also have the potential
to behaviorally disturb marine mammals. Available studies show wide
variation in response to underwater sound; therefore, it is difficult
to predict specifically how any given sound in a particular instance
might affect marine mammals perceiving the signal. If a marine mammal
does react briefly to an underwater sound by changing its behavior or
moving a small distance, the impacts of the change are unlikely to be
significant to the individual, let alone the stock or population.
However, if a sound source displaces marine mammals from an important
feeding or breeding area for a prolonged period, impacts on individuals
and populations could be significant (e.g., Lusseau and Bejder, 2007;
Weilgart, 2007; NRC, 2005).
Disturbance may result in changing durations of surfacing and
dives, number of blows per surfacing, or moving direction and/or speed;
reduced/increased vocal activities; changing/cessation of certain
behavioral activities (such as socializing or feeding); visible startle
response or aggressive behavior (such as tail/fluke slapping or jaw
clapping); avoidance of areas where sound sources are located.
Pinnipeds may increase their haul out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006). Behavioral responses to sound
are highly variable and context-specific and any reactions depend on
numerous intrinsic and extrinsic factors (e.g., species, state of
maturity, experience, current activity, reproductive state, auditory
sensitivity, time of day), as well as the interplay between factors
(e.g., Richardson et al., 1995; Wartzok et al., 2004; Southall et al.,
2007, 2021; Weilgart, 2007; Archer et al., 2010).
[[Page 12375]]
Behavioral reactions can vary not only among individuals but also
within exposures of an individual, depending on previous experience
with a sound source, context, and numerous other factors (Ellison et
al., 2012; Southall et al., 2021), and can vary depending on
characteristics associated with the sound source (e.g., whether it is
moving or stationary, number of sources, distance from the source). In
general, pinnipeds seem more tolerant of, or at least habituate more
quickly to, potentially disturbing underwater sound than do cetaceans,
and generally seem to be less responsive to exposure to industrial
sound than most cetaceans. For a review of the studies involving marine
mammal behavioral responses to sound, see Southall et al., 2007; Gomez
et al., 2016; and Southall et al., 2021 reviews.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al.,
2007). A determination of whether foraging disruptions incur fitness
consequences would require information on 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.
Airborne Acoustic Effects--Pinnipeds that occur near the project
sites could be exposed to airborne sounds associated with pile
installation, pile removal, or DTH drilling that have the potential to
cause behavioral harassment, depending on their distance from the
activities. Cetaceans are not expected to be exposed to airborne sounds
that would result in harassment as defined under the MMPA.
Airborne noise would primarily be an issue for pinnipeds that are
swimming or hauled out near the project sites within the range of noise
levels elevated above the airborne acoustic harassment criteria. We
recognize that pinnipeds in the water could be exposed to airborne
sound that may result in behavioral harassment when swimming with their
heads above water. Most likely, airborne sound would cause behavioral
responses similar to those discussed above in relation to underwater
sound. For instance, anthropogenic sound could cause hauled-out
pinnipeds to exhibit changes in their normal behavior, such as
reduction in vocalizations, or cause them to temporarily abandon the
area and move further from the source. However, these animals would
previously have been `taken' because of exposure to underwater sound
above the behavioral harassment thresholds, which are in all cases
larger than those associated with airborne sound. Thus, the behavioral
harassment of these animals is already accounted for in these estimates
of potential take. Therefore, we do not believe that authorization of
incidental take resulting from airborne sound for pinnipeds is
warranted, and airborne sound is not discussed further here.
Stress Response--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker, 2000;
Romano et al., 2002b) and, more rarely, studied in wild populations
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found
that noise reduction from reduced ship traffic in the Bay of Fundy was
associated with decreased stress in North Atlantic right whales. These
and other studies lead to a reasonable expectation that some marine
mammals 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 around
Kodiak Island.
Auditory Masking--Sound can disrupt behavior through masking, or
interfering with, an animal's ability to detect, recognize, or
discriminate between acoustic signals of interest (e.g., those used for
intraspecific communication and social interactions, prey detection,
predator avoidance, navigation) (Richardson et al., 1995; Erbe et al.,
2016). Masking occurs when the receipt of a sound is interfered with by
another coincident sound at similar frequencies and at similar or
higher intensity, and may occur whether the sound is natural (e.g.,
snapping shrimp, wind, waves, precipitation) or anthropogenic (e.g.,
shipping, sonar, seismic exploration) in origin. The ability of a noise
source to mask biologically important sounds depends on the
characteristics of both the noise source and the signal of interest
(e.g., signal-to-noise ratio, temporal variability, direction), in
relation to each other and to an animal's hearing abilities (e.g.,
sensitivity, frequency range, critical ratios, frequency
discrimination, directional
[[Page 12376]]
discrimination, age or TTS hearing loss), and existing ambient noise
and propagation conditions. Masking of natural sounds can result when
human activities produce high levels of background sound at frequencies
important to marine mammals. Conversely, if the background level of
underwater sound is high (e.g., on a day with strong wind and high
waves), an anthropogenic sound source would not be detectable as far
away as would be possible under quieter conditions and would itself be
masked.
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 man-made, it may be considered harassment
when disrupting or altering critical behaviors. It is important to
distinguish TTS and PTS, which persist after the sound exposure, from
masking, which occurs during the sound exposure. Because masking
(without resulting in TS) is not associated with abnormal physiological
function, it is not considered a physiological effect, but rather a
potential behavioral effect.
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, 2009; 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 (Houser and Moore, 2014). 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 affects both senders and receivers of acoustic signals and
can potentially have long-term chronic effects on marine mammals at the
population level as well as at the individual level. Low-frequency
ambient sound levels have increased by as much as 20 dB (more than
three times in terms of SPL) in the world's ocean from pre-industrial
periods, with most of the increase from distant commercial shipping
(Hildebrand, 2009). All anthropogenic sound sources, but especially
chronic and lower-frequency signals (e.g., from vessel traffic),
contribute to elevated ambient sound levels, thus intensifying masking.
The SHHIRP project is located in an area with commercial and
recreational fishing, recreational boating, ferry operations, and
includes routine vessel traffic; therefore, background sound levels are
generally already elevated.
Marine Mammal Habitat Effects
Proposed construction for Phase I and II of the SHHIRP could have
localized, temporary impacts on marine mammal habitat, including prey,
by increasing in-water SPLs and slightly decreasing water quality.
Increased noise levels may affect acoustic habitat (see Auditory
Masking) and adversely affect marine mammal prey in the vicinity of the
project area (see discussion below). During DTH drilling, impact and
vibratory pile driving, and hydraulic rock hammering elevated levels of
underwater noise would ensonify the project area where both fish and
mammals occur and could affect foraging success. Additionally, marine
mammals may avoid the area during construction; however, displacement
due to noise is expected to be temporary and is not expected to result
in long-term effects to the individuals or populations.
Water Quality--In-water DTH Drilling, pile driving, pile removal,
rock hammering, and dredging activities would also cause short-term
effects on water quality due to increased turbidity. Temporary and
localized increase in turbidity near the seafloor would occur in the
immediate area surrounding where piles are installed or removed and
where rock hammering or dredging will occur, due to benthic sediment
disturbance. In general, turbidity associated with pile installation is
localized to about a 25 ft (7.6 m) radius around the pile (Everitt et
al., 1980). The suspended solids from disturbed sediment at project
sites would 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 from turbidity and sedimentation are expected to be short-
term, minor, and localized. Suspended solids 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, suspended sediment
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 total available marine mammal habitat as well as the
critical habitat and the BIAs around Kodiak, AK. Therefore, we expect
the impact from increased turbidity levels to be discountable to marine
mammals and do not discuss it further.
In-water Effects on Potential Foraging Habitat--The proposed
activities would not result in permanent impacts to habitats used
directly by marine mammals and no increases in vessel traffic are
expected in either location as a result of the specified activities.
The areas likely impacted by the proposed actions are relatively small
compared to the total available habitat in the Gulf of Alaska and the
water surrounding Kodiak Island. The proposed project areas are highly
influenced by anthropogenic activities and provide limited foraging
habitat for marine mammals. The total seafloor area affected by piling
activities is small compared to the vast foraging areas available to
marine mammals surrounding proposed construction sites. At best, the
area impacted provide marginal foraging habitat for marine mammals and
fishes. Furthermore, pile driving, pile removal and hydraulic rock
hammering would not obstruct movements or migration of marine mammals.
Construction activities would produce continuous, non-impulsive
(i.e., vibratory pile driving, DTH drilling) and intermittent impulsive
(i.e., impact pile driving, DTH drilling, and hydraulic rock hammering)
sounds. Fish utilize the soundscape and components of sound in their
environment to perform
[[Page 12377]]
important functions such as foraging, predator avoidance, mating, and
spawning (Zelick et al., 1999; Fay, 2009). Depending on their hearing
anatomy and peripheral sensory structures, which vary among species,
fishes hear sounds using pressure and particle motion sensitivity
capabilities and detect the motion of surrounding water (Fay et al.,
2008). The potential effects of noise on fishes depends on the
overlapping frequency range, distance from the sound source, water
depth of exposure, and species-specific hearing sensitivity, anatomy,
and physiology. Key impacts to fishes may include behavioral responses,
hearing damage, barotrauma (pressure-related injuries), and mortality.
Fish react to sounds which are especially strong and/or
intermittent low-frequency sounds, and behavioral responses such as
flight or avoidance are the most likely effects. Short duration, sharp
sounds can cause overt or subtle changes in fish behavior and local
distribution. The reaction of fish to noise depends on the
physiological state of the fish, past exposures, motivation (e.g.,
feeding, spawning, migration), and other environmental factors.
Hastings and Popper (2005) identified several studies that suggest fish
may relocate to avoid certain areas of sound energy. Additional studies
have documented effects of pile driving on fish, several of which are
based on studies in support of large, multiyear bridge construction
projects (e.g., Scholik and Yan, 2001; Popper and Hastings, 2009). Many
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., Pearson et
al., 1992; Skalski et al., 1992; Santulli et al., 1999; Fewtrell and
McCauley, 2012; Paxton et al., 2017). In response to pile driving,
Pacific sardines (Sardinops sagax) and northern anchovies (Engraulis
mordax) may exhibit an immediate startle response to individual strikes
but return to ``normal'' pre-strike behavior following the conclusion
of pile driving with no evidence of injury as a result (see NAVFAC,
2014). However, some studies have shown no or slight reaction to
impulse sounds (e.g., Wardle et al., 2001; Popper et al., 2005;
Jorgenson and Gyselman, 2009; Pe[ntilde]a et al., 2013).
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function is likely
restored when damaged cells are replaced with new cells. Halvorsen et
al. (2012b) showed that a TTS of 4-6 dB was recoverable within 24 hours
for one species. Impacts would be most severe when the individual fish
is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012a; Casper et al., 2013) and the greatest
potential effect on fish during the proposed project would occur during
impact pile driving, if it is required. However, the duration of impact
pile driving would be limited to a contingency in the event that
vibratory driving does not satisfactorily install the pile depending on
observed soil resistance. In-water construction activities would only
occur during daylight hours allowing fish to forage and transit the
project area at night. Vibratory pile driving may elicit behavioral
reactions from fish such as temporary avoidance of the area but is
unlikely to cause injuries to fish or have persistent effects on local
fish populations. In addition, it should be noted that the area in
question is low-quality habitat since it is already developed and
experiences anthropogenic noise from routine vessel traffic.
The most likely impact to fishes from pile driving, pile removal,
DTH drilling, and hydraulic rock hammering in the project area would be
temporary behavioral avoidance of the area. The duration of fish
avoidance of the area after pile driving stops is unknown but a rapid
return to normal recruitment, distribution, and behavior is
anticipated. There are times of known seasonal marine mammal foraging
when fish are aggregating but the impacted areas are small portions of
the total foraging habitats available in the regions. In general,
impacts to marine mammal prey species are expected to be minor and
temporary. Further, it is anticipated that preparation activities for
pile driving and DTH drilling (i.e., positioning of the hammer) and
upon initial startup of devices would cause fish to move away from the
affected area where injuries may occur. Therefore, relatively small
portions of the proposed project areas would be affected for short
periods of time, and the potential for effects on fish to occur would
be temporary and limited to the duration of sound[hyphen]generating
activities.
Construction activities, in the form of increased turbidity, also
have the potential to adversely affect forage fish in the project area.
Pacific herring (Clupea pallasii) is a primary prey species of Steller
sea lions, humpback whales, and many other marine mammal species that
occur in the project areas. As discussed earlier, increased turbidity
is expected to occur in the immediate vicinity (approximately 25 ft
(7.6 m) or less) of construction activities (Everitt et al., 1980).
However, suspended solids 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 are expected to be minor or
negligible. In addition, best management practices would be in effect
to limit the extent of turbidity to the immediate project areas.
Finally, exposure to turbid waters from construction activities is not
expected to be different from the current exposure; fish and marine
mammals in the regions are routinely exposed to substantial levels of
suspended sediment from glacial sources.
In summary, given the short daily duration of sound associated with
pile driving, DTH drilling, and hydraulic rock hammering and the
relatively small areas being affected by these activities associated
with the proposed actions are not likely to have a permanent adverse
effect on any fish habitat, or populations of fish species. Thus, we
conclude that impacts of the specified activity are not likely to have
more than short-term adverse effects on any prey habitat or populations
of prey species. Further, any impacts to marine mammal habitat are not
expected to result in significant or long-term consequences for
individual marine mammals, or to contribute to adverse impacts on their
populations.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
proposed for authorization through the IHAs, 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).
[[Page 12378]]
Authorized takes would primarily be by Level B harassment, as use
of the acoustic sources (i.e., impact, and vibratory pile driving; DTH
drilling; vibratory pile removal; and hydraulic rock hammering) has the
potential to result in disruption of behavioral patterns for individual
marine mammals. There is also some potential for AUD INJ (Level A
harassment) to result, primarily for Dall's porpoise, harbor porpoise,
harbor seal, and Steller sea lion because predicted AUD INJ zones are
larger than for other species and those four species are more commonly
seen within the area. AUD INJ is unlikely to occur for gray whale,
minke whale, fin whale, humpback whale, Pacific white-sided dolphin,
killer whale, northern fur seal, and northern elephant seal. 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). Criteria for AUD INJ, and hearing group categories
are available in NMFS' Updated Technical Guidance (NMFS 2024) and are
reflected below in the Level A harassment section.
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g.,
scientific sonar) sources. Generally speaking, Level B harassment take
estimates based on these behavioral harassment thresholds are expected
to include any likely takes by TTS as, in most cases, the likelihood of
TTS occurs at distances from the source less than those at which
behavioral harassment is likely. TTS of a sufficient degree can
manifest as behavioral harassment, as reduced hearing sensitivity and
the potential reduced opportunities to detect important signals
(conspecific communication, predators, prey) may result in changes in
behavior patterns that would not otherwise occur.
The City of Kodiak's proposed activities includes the use of
continuous (vibratory pile driving/removal and DTH drilling) and
intermittent (impact pile driving, DTH drilling, and hydraulic rock
hammering) sources, and therefore the RMS SPL thresholds of 120 and 160
dB re 1 [mu]Pa, respectively, are applicable.
Level A Harassment--NMFS' Updated Technical Guidance for Assessing
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version
3.0) (Updated Technical Guidance, 2024) identifies dual criteria to
assess AUD INJ (Level A harassment) to five different underwater marine
mammal groups (based on hearing sensitivity) as a result of exposure to
noise from two different types of sources (impulsive or non-impulsive).
The City of Kodiak's proposed activity includes the use of impulsive
(impact pile driving, hydraulic rock hammering, and DTH drilling) and
non-impulsive (vibratory pile driving/removal and DTH drilling)
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 5--Thresholds Identifying the Onset of Auditory Injury
----------------------------------------------------------------------------------------------------------------
AUD INJ Onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 222 dB; Cell 2: LE,LF,24h: 197 dB.
LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans.......... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,HF,24h: 201 dB.
LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans.... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,VHF,24h: 181 dB.
LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 223 dB; Cell 8: LE,PW,24h: 195 dB.
LE,PW,24h: 183 dB.
[[Page 12379]]
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 230 dB; Cell 10: LE,OW,24h: 199 dB.
LE,OW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
*Dual metric criteria for impulsive sounds: Use whichever criteria results in the larger isopleth for
calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure
level criteria associated with impulsive sounds, the PK SPL criteria are recommended for consideration for non-
impulsive sources.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
exposure level (LE,p) has a reference value of 1 [mu]Pa\2\s. In this table, criteria are abbreviated to be
more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
hearing range of marine mammals underwater (i.e., 7 Hz to 165 kHz). The subscript associated with cumulative
sound exposure level criteria indicates the designated marine mammal auditory weighting function (LF, HF, and
VHF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The weighted
cumulative sound exposure level criteria could be exceeded in a multitude of ways (i.e., varying exposure
levels and durations, duty cycle). When possible, it is valuable for action proponents to indicate the
conditions under which these criteria will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss (TL)
coefficient.
The sound field in the proposed project area is the existing
background noise plus additional construction noise from the proposed
project. Marine mammals are expected to be affected via sound generated
by the primary components of Phase I and II of the SHHIRP activities
(i.e., pile installation, pile removal, DTH drilling and hydraulic rock
hammering).
The source levels assumed for pile installation, pile removal, and
rock hammering activities are based on reviews of measurements of the
same or similar types and dimensions of piles and rock hammering
activities from similar coastal construction projects. We note that the
City of Kodiak proposed a source level of 155 dB RMS SPL for the
vibratory installation of 16- to 18-inch steel piles during Phase II of
the SHHIRP Project, citing Denes et al. (2016). However, NMFS has
determined that use of this proxy source level in this location is not
appropriate; the substrate in Kake, AK, where the data in Denes et al.
(2016) were collected is primarily mud, and source levels recorded at
that location are consistently lower than those measured elsewhere in
Alaska (Navy 2012, 2013; Minor 2020). Consequently, NMFS applied a more
appropriate source level of 163 dB RMS SPL to 16- and 18-in piles.
These source levels were derived from recordings in Bangor, Washington,
and Gustavus, Alaska, where pile sizes and substrate are similar to the
project area.
Table 6--Estimated Source Levels (at 10 m), by Pile Size, Type and Activity, for the SHHIRP
----------------------------------------------------------------------------------------------------------------
RMS SPL (dB SEL (dB re Peak SPL
Pile size and type re 1 1 [mu]Pa2- (dB re 1 Reference
[mu]Pa) sec) [mu]Pa)
----------------------------------------------------------------------------------------------------------------
Vibratory pile installation and removal
----------------------------------------------------------------------------------------------------------------
12- to 20-inch steel piles (removal).... 163 N/A N/A Naval Base Kitsap Bangor Test
Pile (Navy (2012)) and EHW-2
(Navy (2013)), Gustavus
(Minor, 2020).
16- to 24-inch steel piles.............. 163 N/A N/A Naval Base Kitsap Bangor Test
Pile (Navy (2012)) and EHW-2
(Navy (2013)), Gustavus
(Minor, 2020).
30-inch steel piles..................... 166 N/A N/A Denes et al. 2016 (Auke Bay,
Ketchikan, Kake), Edmonds
Ferry Terminal (Laughlin 2011,
2017), Colman Dock--Seattle
Ferry Terminal (Laughlin
2012), Kodiak Pier 3 (PND
Engineers, 2015).
----------------------------------------------------------------------------------------------------------------
Impact pile installation
----------------------------------------------------------------------------------------------------------------
16- to 18-inch steel piles.............. 185 175 200 Caltrans 2020.
20- to 24-inch steel piles.............. 190 177 203 Caltrans 2015.
30-inch steel piles..................... 190 177 210 Caltrans 2015.
----------------------------------------------------------------------------------------------------------------
DTH pile drilling
----------------------------------------------------------------------------------------------------------------
16-18-inch steel piles.................. 167 146 172 Guan and Miner 2020; Heyvaert
and Reyff 2021.
20-24-inch steel piles.................. 167 159 184 Heyvaert and Reyff 2021.
30-inch steel piles..................... 174 164 194 Denes et al. 2019; Reyff and
Heyvaert 2019; Reyff 2020;
Heyvaert and Reyff 2021.
----------------------------------------------------------------------------------------------------------------
Hydraulic hammering/rock fracturing
----------------------------------------------------------------------------------------------------------------
Hydraulic hammering/rock fracturing..... 186 171 197 Escude 2012.
----------------------------------------------------------------------------------------------------------------
[[Page 12380]]
Transmission Loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater TL is:
TL = B x Log10(R1/R2)
Where:
TL = transmission loss in dB,
B = transmission loss coefficient,
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement.
This formula neglects loss due to scattering and absorption, which
is assumed to be zero here. The degree to which underwater sound
propagates away from a sound source 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 shallow-water coastal conditions, such as those
found in St. Herman Harbor. In these environments, sound waves
repeatedly reflect off the surface and bottom, reflecting an expected
propagation environment between spherical and cylindrical spreading-
loss conditions.
Site-specific TL data for St. Herman Harbor is not available;
therefore, the default coefficient of 15 is used to calculate distances
to the Level A harassment and Level B harassment thresholds. Assuming
practicable spreading and other assumptions regarding the source
characteristics and operational logistics (e.g., source level, number
of strikes per pile, number of piles per day), the City of Kodiak and
NMFS calculated distances to the Level A harassment and Level B
harassment thresholds and associated ensonified areas. Because an
ensonified area associated with Level A harassment is more technically
challenging to predict given the accounting for a cumulative energy
component that changes over time, to assist applicants in assessing the
potential for Level A harassment without the need for complex modeling,
NMFS developed an optional User Spreadsheet tool to accompany the 2024
Updated Technical Guidance (see <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-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 data to predict
the amount of take that may occur incidental to an activity. We note
that, because of some of the assumptions in the methods underlying this
spreadsheet tool, we anticipate that the resulting isopleths would
typically be overestimates, which may lead to an overestimate of
potential exposures from Level A harassment. However, this optional
tool offers the best way to estimate isopleth distances when more
sophisticated modeling methods are not available or practical. For
stationary sources such pile installation, pile removal, DTH drilling,
and hydraulic rock hammering, 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, and
the resulting estimated isopleths, are reported in table 7 through 10
below. Discrepancies between the distances and associated areas to
thresholds presented in Table 10 and the City of Kodiak's application
for 16- and 18-in piles result from different source levels used by
NMFS as described above.
Table 1--NMFS User Spreadsheet Inputs for Phase I of the SHHIRP
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Number of strikes
Weighting Transmission Activity per pile (impact) Number of Distance of sound
Pile size and material Spreadsheet tab used Source level (SPL) factor loss duration or repetition piles per day pressure level
adjustment coefficient (minutes) rate (DTH) measurement (m)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory pile driving
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
24-inch steel........................... A.1) Vibratory Pile 163 dB RMS................ 2.5 15 20 N/A 6 10
Driving.
24-inch steel \a\....................... 163 dB RMS................ 2.5 15 20 N/A 6 10
30-inch steel........................... 166 dB RMS................ 2.5 15 20 N/A 6 10
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory pile removal
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
24-inch steel........................... A.1) Vibratory Pile 163 dB RMS................ 2.5 15 20 N/A 6 10
Driving.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Impact pile driving
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
24-inch steel \a\....................... E.1) Impact Pile Driving.. 177 dB SEL................ 2 15 15 300 6 10
24-inch steel........................... 177 dB SEL................ 2 15 45 1,800 6 10
30-inch steel........................... 177 dB SEL................ 2 15 45 1,800 6 10
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
DTH pile drilling
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
24-inch steel \a\....................... E.2) DTH Systems.......... 159 dB SEL................ 2 15 120 \b\ 10 6 10
24-inch steel........................... 159 dB SEL................ 2 15 150 \b\ 10 6 10
30-inch steel........................... 164 dB SEL................ 2 15 150 \b\ 10 6 10
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: N/A means not applicable.
\a\ indicates temporary piles.
\b\ The City of Kodiak estimates a repetition rate of 10 Hz which falls within the range measured during other projects in Southeast Alaska (Heyyaert and Reyff, 2021; Denes et al., 2016) While
actual repetition rate may be higher, for purposes of this analysis, 10 Hz is a reasonable value to apply.
[[Page 12381]]
Table 2--NMFS User Spreadsheet Inputs for Phase II of the SHHIRP
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Activity
duration Number of strikes Number of
Weighting Transmission (minutes) or per pile (impact) piles per day Distance of sound
Pile size and material Spreadsheet tab used Source level (SPL) factor loss total hours or repetition or total cubic pressure level
adjustment coefficient (rock rate (DTH) yards (rock measurement (m)
hammering) hammering)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory pile driving
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
16- to 18-inch steel................... A.1) Vibratory Pile 163 dB RMS............... 2.5 15 20 N/A 6 10
Driving.
20-inch steel.......................... 163 dB RMS............... 2.5 15 20 N/A 6 10
24-inch steel \a\...................... 163 dB RMS............... 2.5 15 20 N/A 6 10
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory pile removal
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
12- to 20-inch steel Removal \b\....... A.1) Vibratory Pile 163 dB RMS............... 2.5 15 10 N/A 20 10
Driving.
24-inch steel \a\...................... 163 dB RMS............... 2.5 15 20 N/A 6 10
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Impact pile driving
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
16-inch steel.......................... E.1) Impact Pile Driving. 175 dB SEL............... 2 15 45 1,800 6 10
18-inch steel.......................... 175 dB SEL............... 2 15 45 1,800 6 10
20-inch steel.......................... 177 dB SEL............... 2 15 45 1,800 6 10
24-inch steel \a\...................... 177 dB SEL............... 2 15 45 1,800 6 10
24-inch steel.......................... 177 dB SEL............... 2 15 15 300 6 10
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
DTH pile drilling
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
16-inch steel.......................... E.2) DTH Systems......... 146 dB SEL............... 2 15 150 \c\ 10 6 10
18-inch steel.......................... 146 dB SEL............... 2 15 150 \c\ 10 6 10
20-inch steel.......................... 159 dB SEL............... 2 15 150 \c\ 10 6 10
24-inch steel.......................... 159 dB SEL............... 2 15 150 \c\ 10 6 10
24-inch steel \a\...................... 159 dB SEL............... 2 15 120 \c\ 10 6 10
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Hydraulic rock hammering
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Rock hammering......................... E: Stationary source..... 171 dB SEL............... 2 15 250 24,000 1,900 10
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: N/A means not applicable.
\a\ indicates temporary piles.
\b\ indicates existing piles.
\c\ The City of Kodiak estimates a repetition rate of 10 Hz which falls within the range measured during other projects in Southeast Alaska (Heyvaert and Reyff, 2021; Denes et al., 2016) While
actual repetition rate may be higher, for purposes of this analysis, 10 Hz is a reasonable value to apply.
Table 9--Projected Distances to Level A Harassment and Level B Harassment Isopleths (m) and Associated Areas (km\2\) by Marine Mammal Hearing Groups for
Vibratory Installation and Removal, Impact Installation, and DTH Drilling of Piles for Phase I of the SHHIRP
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment distance (m), (area (km\2\))
-------------------------------------------------------------------------------- Level B
Pile size and material Very high harassment
Low frequency High frequency frequency Phocids Otariids distance (m),
cetaceans cetaceans cetaceans (area (km\2\))
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory pile driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-inch steel \a\....................................... 19.9 (0.014) 7.6 (0.004) 16.3 (0.011) 25.6 (0.018) 8.6 (0.006) 7,356 (6.641)
30-inch steel........................................... 31.5 (0.023) 12.1 (0.008) 25.8 (0.018) 40.6 (0.03) 13.7 (0.009) 11,659 (9.263)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact pile driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-inch steel \b\....................................... 586.1 (0.44) 74.8 (0.06) 907.1 (0.664) 520.7 (0.399) 194.1 (0.191) 1,000 (0.71)
24-inch steel........................................... 1,935.4 246.9 (0.239) 2,995.1 1,719.3 640.9 (0.475) 1,000 (0.71)
(1.191) (2.128) (1.052)
30-inch steel........................................... 1,935.4 246.9 (0.239) 2,995.1 1,719.3 640.9 (0.475) 1,000 (0.71)
(1.191) (2.128) (1.052)
--------------------------------------------------------------------------------------------------------------------------------------------------------
DTH pile drilling
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-inch steel \b\....................................... 1,428.3 182.2 (0.177) 2,210.3 1,268.8 473 (0.37) \c\ \d\ 13,594
(0.893) (1.393) (0.819) (9.269)
24-inch steel........................................... 1,657.4 211.5 (0.208) 2,564.8 1,472.3 548.8 (0.417) \c\ \d\ 13,594
(1.016) (1.696) (0.915) (9.269)
[[Page 12382]]
30-inch steel........................................... 3,570.7 455.6 (0.359) 5,525.7 3,172.1 (2.33) 1,185.4 \c\ \d\ 39,811
(2.815) (5.241) (0.783) (9.269)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ indicates both temporary and permanent piles.
\b\ indicates temporary piles only.
\c\ Distances represent the calculated radius of the zone. The actual zone may be truncated by landforms.
\d\ Areas of zones accounting for truncation by landforms.
Table 10--Projected Distances to Level A Harassment and Level B Harassment Isopleths (m) and Associated Areas (km\2\) by Marine Mammal Hearing Groups
for Vibratory Installation and Removal, Impact Installation, and DTH Drilling of Piles and Hydraulic Rock Hammering for Phase II of the SHHIRP
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment distance (m), (area (km\2\))
-------------------------------------------------------------------------------- Level B
Pile size and material Very high harassment
Low frequency High frequency frequency Phocids Otariids distance (m),
cetaceans cetaceans cetaceans (area (km\2\))
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory pile driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
12- to 20-inch piles \a\................................ 28 (0.0256) 10.7 (0.01) 22.9 (0.022) 36 (0.031) 12.1 (0.012) 7,356 (6.399)
16- or 18-inch steel piles.............................. 19.9 (0.019) 7.6 (0.007) 16.3 (0.016) 25.6 (0.024) 8.6 (0.008) 7,356 (6.399)
20- to 24-inch steel piles \b\.......................... 19.9 (0.019) 7.6 (0.007) 16.3 (0.016) 25.6 (0.024) 8.6 (0.008) 7,356 (6.399)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact pile driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
16- to 18-inch steel piles.............................. 1,423.8 181.7 (0.117) 2,203.3 1,264.8 471.5 (0.437) 464 (0.428)
(0.831) (1.224) (0.778)
24-inch steel piles \c\................................. 586.1 (0.552) 74.8 (0.05) 907.1 (0.679) 520.7 (0.494) 194.1 (0.127) 1,000 (0.703)
20- to 24-inch steel.................................... 1,935.4 246.9 (0.174) 2,995.1 1,719.3 640.9 (0.59) 1,000 (0.703)
(1.063) (1.856) (0.953)
--------------------------------------------------------------------------------------------------------------------------------------------------------
DTH pile drilling
--------------------------------------------------------------------------------------------------------------------------------------------------------
16- or 18-inch steel.................................... 225.3 (0.154) 28.7 (0.026) 348.6 (0.289) 200.1 (0.131) 74.6 (0.05) \d\ \e\ 13,594
(9.159)
24-inch steel piles \c\................................. 1,428.3 182.2 (0.117) 2,210.3 1,268.8 473 (0.439) \d\ \e\ 13,594
(0.832) (1.228) (0.779) (9.159)
20- or 24-inch steel.................................... 1,657.4 211.5 (0.141) 2,564.8 1,472.3 548.8 (0.518) \d\ \e\ 13,594
(0.925) (0.1555) (0.848) (9.159)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rock hammering
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rock hammering.......................................... 609 (0.252) 77.7 (0.034) 942.5 (0.331) 541 (0.227) 201.7 (0.095) 541 (0.227)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ indicates removal of existing piles.
\b\ indicates both temporary and permanent piles.
\c\ indicates installation of temporary piles only.
\d\ Distances represent the calculated radius of the zone. The actual zone may be truncated by landforms.
\e\ Areas of zones accounting for truncation by landforms.
Level A harassment zones are typically smaller than Level B
harassment zones. However, in rare cases such as during impact driving
of 24- and 30-inch permanent steel piles for Phase I and during impact
driving 16-, 18-, 20-, and 24-inch permanent steel piles, the
calculated Level A harassment isopleth is larger than the calculated
Level B harassment isopleth for low frequency (LF) cetaceans, very
high-frequency (VHF) cetaceans, and phocids (tables 9 and 10). This
phenomenon also applies to rock hammering in Phase II for LF and VHF
cetaceans. Calculation of Level A harassment isopleths include a
duration component, which in the case of impact pile driving and rock
hammering, is estimated through the total number of daily strikes and
the associated pulse duration. For a stationary sound source such as
impact pile driving and rock hammering, the calculated distances assume
that an animal is exposed to all of the strikes expected within a 24-
hour period and, as described above, is therefore likely an
overestimate. Calculation of a Level B harassment isopleth does not
include a duration component.
Marine Mammal Occurrence and Take Estimation
In this section we provide information about the occurrence of
marine mammals, including density or other relevant information which
will inform the take calculations.
[[Page 12383]]
Below we present available information regarding marine mammal
occurrence in the vicinity of the project area and includes site-
specific survey information and knowledge from local tribes. Data
sources consulted included: (1) anecdotal input and data provided by
the Sun'aq Tribe of Kodiak's Natural Resources Director (Van Daele,
Personal communication, 2025), (2) Protected Species Observer (PSO)
monitoring completed in Near Island Channel on 110 days between
November 205 and June 2016 during the Kodiak Ferry Terminal and Dock
Improvements Project, approximately 1.2 km northeast of St. Herman
Harbor (ABR Inc., 2016), and (3) density data from the Navy Marine
Species Density Database for the U.S Pacific and Gulf of Alaska (Marine
Geospatial Ecology Lab, 2021).
Take, by Level A harassment, is predicted to occur for activities
wherein the shutdown zones (described below) are smaller than the
calculated Level A harassment zones. Take, by Level A harassment, for
VHF cetaceans and phocids for both Phase I and Phase II of the SHHIRP
were calculated using the following equations:
Take by Level A harassment = (activity's Level A harassment area
[km\2\]) x estimated density [individuals/km\2\]) x days of pile
installation/removal, DTH drilling, and rock hammering
We note that in their application, the City of Kodiak subtracted
the shutdown areas (km\2\) from Level A harassment areas in their
calculations. NMFS does not agree with this approach, as an animal
could enter harassment zones before detection, thus could be taken by
Level B harassment before shutdowns could be implemented. Therefore,
NMFS applied to full Level A harassment zone calculated from the User
Spreadsheet to estimate take.
This formula was applied to all impact pile driving and DTH
drilling during Phase I. For Phase II, the formula was applied to all
impact pile driving, rock hammering, and the DTH drilling of 24-inch
temporary and 20- to 24-inch permanent steel piles. For all other
activities (e.g., vibratory removal and driving), Level A harassment
does not have the potential to occur based on the analysis. The
occurrence data sources used in the Level A harassment calculation
above included marine mammal density from source 3 (Marine Geospatial
Ecology Lab, 2021). The total calculated amount of Level A harassment
proposed for authorization during Phase I and Phase II of the SHHIRP
for Dall's porpoise, harbor porpoise, and harbor seals are presented in
table 11. The methodologies which have been used to quantify Level A
harassment for Steller sea lions are provided in the respective species
section below as density data was not a good indicator of the potential
for harassment given Steller sea lion use of the project area.
We acknowledge that the number of estimated exposures above higher
threshold criteria, e.g., sound exposures exceeding Level A harassment
criteria, also encompass the potential for less impactful effects,
e.g., Level B harassment. An individual exposure exceeding a Level A
harassment criterion may not result in actual auditory injury, yet the
individual may have experienced Level B harassment. This outcome is
accounted for in our authorization of potential higher-level takes and
in our analysis. Specifically, due to this approach for calculating
Level A harassment and Level B harassment for VHF cetaceans and
phocids, the number of authorized takes by Level A harassment may be
applied to observations of Level B harassment. However, the total
number of takes may not exceed the sum of the takes authorized by Level
A and Level B harassment (table 11).
For species where density data were available and accurately
represented the potential for Level B harassment (i.e., fin whale,
humpback whale, dolphin, VHF cetaceans, and phocids) and where Level B
harassment isopleths are larger than the Level A harassment isopleths,
the following equation was used to estimate take:
Take by Level B harassment = (activity level B harassment area [km\2\]-
activity level A harassment area [km\2\]) x estimated density
[individuals/km\2\] x days of pile installation/removal and DTH
drilling where days of pile installation/removal and DTH drilling
equate to 32 and 163 (days Level B harassment Isopleths are larger than
Level A harassment Isopleths) for Phase I and Phase II, respectively
The methodologies which have been used to quantify Level B
harassment for the Steller sea lion, killer whale and other
infrequently occurring species (minke whale, Pacific white-sided
dolphin, northern elephant seal, and northern fun seal) within the
project areas, are detailed in their respective species-specific sub-
sections below.
Gray Whale--The City of Kodiak estimated that one gray whale could
occur within the Level B harassment zone per month (30 days) during
each construction phase because they are considered rare construction
area. This is based on small numbers of gray whales observed in Chiniak
Bay, approximately 8 km from the project area (Sea Grant Alaska, 2012)
NMFS concurs with this frequency-based approach. Given there are 42
estimated days of work for Phase I and 227 estimated days of work for
Phase II, the City of Kodiak requested, and NMFS proposes to authorize,
two takes by Level B harassment for Phase I and eight takes by Level B
harassment for Phase II. Estimated takes by Level B harassment were
rounded to the next whole number. Takes by Level A harassment of gray
whales are not anticipated and therefore not proposed for
authorization.
Fin Whale--Considering fin whales presence near the proposed
project areas, they could enter Level B harassment zones daily (32 days
for Phase I and 163 for Phase II). Based on a density of 0.068
individuals per square kilometer (km\2\) (Marine Geospatial Ecology
Lab, 2021), the City of Kodiak requested 16 takes by Level B harassment
for Phase I and 68 takes by Level B harassment for Phase II) based on
their calculations. However, NMFS revised the vibratory source levels
for 16-inch and 18-inch steel piles to reflect the best available
science. This revision expanded the Phase II Level B harassment
isopleth, increasing the takes by Level B harassment from 68 to 75
whales. Accordingly, NMFS proposes to authorize 16 takes by Level B
harassment for Phase I and 75 for Phase II. Takes by Level A harassment
for fin whales are not anticipated and therefore not proposed for
authorization.
Humpback Whale--Considering humpback whales' presence near the
proposed project areas, they could enter Level B harassment zones daily
(32 days for Phase I and 163 for Phase II). Humpback whales are
expected to occur at a density of 0.093 individuals per km\2\ (Marine
Geospatial Ecology Lab, 2021). However, upon review of the application,
NMFS adjusted the Level B harassment take estimates for humpback whales
to account for revised vibratory source levels for 16- to 18-inch steel
piles, which expanded the Level B harassment isopleth for Phase II.
Consequently, the calculated take estimate for Phase II increased from
93 to 103 humpback whale. Therefore, NMFS proposes to authorize 22 and
103 takes by Level B harassment for Phase I and II, respectively.
In the SHHIRP areas, it is estimated that the majority of whales
(89 percent) will be from the Hawaii DPS, 11 percent will be from the
Mexico-North Pacific
[[Page 12384]]
DPS, and 1 percent will be from the endangered Western North Pacific
DPS (Wade, 2021; Muto et al., 2022). Therefore, for Phase I, 19 takes
are assumed to be from the Hawaii DPS, 2 takes from the Mexico-North
Pacific DPS, and 1 take from the Western North Pacific DPS. For Phase
II, 91 are assumed to be from the Hawaii DPS, 11 takes from the Mexico-
North Pacific DPS, and 1 Western North Pacific DPS. Takes by Level A
harassment for humpback whales are not anticipated and therefore not
proposed for authorization.
Minke Whale--Minke whales are often sighted individually and are
considered rare within the project area. The City of Kodiak estimated
that one group of one minke whale could occur within the Level B
harassment zone per month (30 days) during each construction phase.
NMFS concurs with this frequency-based approach and proposes to
authorize two takes by Level B harassment for Phase I (42 days) and
eight takes by Level B harassment for Phase II (227 days). Estimated
takes by Level B harassment was rounded to the next whole number. Takes
by Level A harassment for minke whales are not anticipated and
therefore not proposed for authorization.
Killer Whale--Based on previous sightings at the Kodiak Ferry
Terminal of groups of three to seven animals (ABR, 2016), the City of
Kodiak estimated one group of six animals could occur every 10 days.
NMFS concurs with this approach and proposes to authorize 26 takes by
Level B harassment for Phase I (42 days) and 137 takes by Level B
harassment for Phase II (227 days). In the action area it is estimated
that the majority of killer whales (80 percent) will be from the Alaska
resident stock and 20 percent will be from the Gulf of Alaska/Aleutian
Islands/Bering Sea transient stock (Muto et al., 2022). Therefore, for
Phase I, 20 takes are assumed to be from the Alaska resident stock and
6 takes from the Gulf of Alaska/Aleutian Islands/Bering Sea transient
stock. For Phase II, 105 takes are assumed to be from the Alaska
resident stock and 32 takes from the Gulf of Alaska/Aleutian Islands/
Bering Sea transient stock. Takes by Level A harassment for killer
whales are not anticipated and therefore not proposed for
authorization.
Pacific White-sided Dolphin--Pacific white-sided dolphin group
sizes are usually between 10 and 100 animals. This species is rare in
shallow, enclosed waters like the construction areas in St. Herman
Harbor. However, to account for the potential for Pacific white-sided
dolphins to enter construction areas, the City of Kodiak estimated that
1 group of 10 animals could enter Level B harassment zones during Phase
I construction, and 2 groups of 10 animals could enter Level B
harassment zones during Phase II construction. NMFS concurs with this
approach and proposes to authorize take by Level B harassment of 10
Pacific white-sided dolphins for Phase I and 20 for Phase II. Takes by
Level A harassment of Pacific white-sided dolphins are not anticipated
and therefore not proposed for authorization.
Dall's Porpoise--Dall's porpoises are year-round residents of the
waters surrounding Kodiak Island and are frequently observed near the
proposed project area. Therefore, Dall's porpoises are anticipated to
occur in the project areas during construction activities. In the
proposed project areas, Dall's porpoises are expected to occur at a
density of 0.218 individuals per km\2\ (Marine Geospatial Ecology Lab,
2021). Using the Level B harassment equation above, the City of Kodiak
requested 45 and 213 takes by Level B harassment for Phase I and Phase
II, respectively. However, upon review of the application, NMFS
adjusted the Level B harassment take estimates for Dall's porpoises to
account for revised vibratory source levels for 16- to 18-inch steel
piles, which expanded the Level B harassment isopleth for Phase II.
Consequently, the calculated take estimate for Phase II increased from
213 to 236 Dall's porpoise. Based on this revision, NMFS proposes to
authorize 45 takes for Phase I and 236 takes for Phase II by Level B
harassment.
Construction activities for both phases include impact pile driving
and DTH drilling, with rock hammering occurring exclusively during
Phase II. During each of these activities, Level A harassment isopleths
are larger than Level B harassment isopleths. The City of Kodiak used
the expected density of 0.218 individuals per km\2\ with the equation
provided in their application and requested 15 takes by Level A
harassment for Phase I and 21 for Phase II. However, the equation in
their application subtracts the proposed shutdown zone areas from the
Level A harassment zone areas. To account for potential undetected
entry of animals into shutdown zones, NMFS modified the City of
Kodiak's Level A harassment equation (provided above) and did not
deduct the shutdown zone area from the Level A harassment area.
Therefore, NMFS proposes to authorize 17 takes during Phase I and 28
takes during Phase II for Dall's porpoise by Level A harassment.
Harbor Porpoise--Harbor porpoises are present in Kodiak year-round
and are frequently observed near the proposed action areas. Therefore,
harbor porpoises are anticipated to occur in the project areas during
construction activities. In the proposed project areas, harbor
porpoises are expected to occur at a density of 0.0473 individuals per
km\2\ (Marine Geospatial Ecology Lab, 2021). Using the Level B
harassment equation above, the City of Kodiak requested 10 and 47 takes
by Level B harassment for Phase I and Phase II, respectively. However,
upon review of the application, NMFS adjusted the Level B harassment
take estimates for harbor porpoises to account for revised vibratory
source levels for 16- to 18-inch steel piles, which expanded the Level
B harassment isopleth for Phase II. Consequently, the calculated take
estimate for Phase II increased from 47 to 52 harbor porpoises. Based
on this revision, NMFS proposes to authorize 10 takes for Phase I and
52 takes for Phase II by Level B harassment.
Using the Level A harassment methodology and density estimates
described above, NMFS proposed to authorize 4 and 7 takes by Level A
harassment of harbor porpoise during Phase I and Phase II,
respectively.
Steller Sea Lions--Steller sea lions are considered common in the
project areas and are expected to occur in the project areas daily. The
Sun'aq Tribe of Kodiak conducted single day counts of Steller sea lions
hauled out at the Dog Bay Float once per month during March, May, June,
and September 2023; January, April, May, and October 2024; and March,
May, July, and September 2025 (Van Daele, pers. communication, 2025).
Across 12 single-day counts conducted by the Sun'aq Tribe of Kodiak,
Steller sea lion abundance at the Dog Bay Float averaged 125
individuals, ranging from a minimum of 0 (June 2023 and July 2025) to a
maximum of 226 (May 2025). Based on these data and in consideration
that the specified activities could occur throughout the year during
times when Steller sea lion presence is low, the City of Kodiak
estimated that 125 individuals could enter Level B harassment zones
daily during Phase I construction and 75 individuals could enter Level
B harassment zones daily during Phase II construction. The difference
between these daily estimates was proposed by the applicant because of
the different distances from construction areas to the Dog Bay Float.
However, NMFS assumes animals are expected to pass through Phase I and
Phase II harassment zones at the same frequency as they transit to and
from the
[[Page 12385]]
Dog Bay Float. Therefore, NMFS expects that 125 Stellar sea lions could
enter Level B harassment zones during each day (42 days for Phase I and
227 days for Phase II) of construction and proposes to authorize 5,250
takes by Level B harassment for Phase I and 25,875 for Phase II.
Throughout these sea lion counts, observers documented multiple
Steller sea lions with identifiable marking (e.g., branded animals) or
scars each time. Recurring observations of the same individuals with
distinct identifiable markings indicates that the Stellar sea lions
that regularly haulout on the Dog Bay Float consists of a semi-closed
population of approximately 300 animals (Van Daele, Personal
communication, 2025).
NMFS considered this information when determining the amount of
Level A harassment that may occur. Based on the calculation methodology
provided above, the instances of Level A harassment are likely a gross
overestimate of take as the same individuals are likely to remain in
the project area, increasing the risk of incurring AUD INJ. While NMFS
recognizes some individuals may leave and others may move in, a more
appropriate and representative potential for Level A harassment can be
derived by the number of individuals occurring in the action area. As
described above, there are likely approximately 300 Steller sea lions
that use the Dog Bay Float based on sighting data. Assuming all 300
accrue enough sound energy to elicit AUD INJ, the City of Kodiak
requests (300 takes, by Level A harassment, for Phase I and 300 takes,
by Level A harassment, for Phase II). While some animals may reoccur
between Phase I and Phase II, there may be sufficient time between
phases where new animals move in. Therefore, we are conservatively
proposing to authorize the same amount of AUD INJ (300 takes) in both
IHAs.
This approach is further justified in consideration of the type of
impact that may occur. As described in the Potential Effects of
Specified Activities on Marine Mammals and Their Habitat section, AUD
INJ is a permanent injury, however, animals may experience partial or
incomplete recovery above baseline hearing levels.
Northern Elephant Seal--Northern elephant seals are considered rare
within the project area. However, a recent observation of a hauled-out
northern elephant seal by the Sun'aq tribe of Kodiak indicates that the
species has the potential to be in the project area during construction
(Van Daele, Personal communication, 2025). The city of Kodiak estimated
that one northern elephant seal could enter the Level B harassment zone
every month (30 days) during each phase of the proposed construction
activities. NMFS concurs with this frequency-based approach and
proposes to authorize two takes by Level B harassment for Phase I (42
days) and eight takes by Level B harassment for Phase II (227 days).
Estimated takes by Level B harassment was rounded to the next whole
number. Takes by Level A harassment of northern elephant seals are not
anticipated and therefore not proposed for authorization.
Northern Fur Seal--Northern fur seals are considered rare within
the project area. Although rare, it is possible that northern fur seals
would enter project areas during construction activities. The City of
Kodiak estimated that one northern fur seal could enter the Level B
harassment zone every month (30 days) during each phase of the proposed
construction activities. NMFS concurs with this approach and proposes
to authorize two takes by Level B harassment for Phase I (42 days) and
eight takes by Level B harassment for Phase II (227 days). Estimated
takes by Level B harassment were rounded to the next whole number.
Takes by Level A harassment of northern fur seals are not anticipated
and therefore not proposed for authorization.
Harbor Seal--Harbor seals are present in Kodiak year-round and are
frequently observed near the proposed action areas. Therefore, harbor
seals are anticipated to occur in the project areas during construction
activities. The City of Kodiak used the expected density of 0.1689
individuals per square kilometer area (Marine Geospatial Ecology Lab,
2021). Using the Level B harassment equation above, the City of Kodiak
requested 37 and 170 takes by Level B harassment of harbor seals during
Phase I and Phase II, respectively. However, upon review of the
application, NMFS adjusted the Level B harassment take estimates for
harbor seals to account for revised vibratory source levels for 16- to
18-inch steel piles, which expanded the Level B harassment isopleth for
Phase II. Consequently, the calculated exposure estimate for Phase II
increased from 170 to 187 harbor seals. Therefore, NMFS proposes to
authorize 37 takes for Phase I and 187 takes for Phase II by Level B
harassment.
Using the Level A harassment methodology and density estimates
described above, NMFS proposed to authorize 6 and 13 takes by Level A
harassment of harbor seal during Phase I and Phase II, respectively.
Table 11--Proposed Take of Marine Mammals by Level A and Level B Harassment and Percent of Each Stock Expected To Be Take for Phase I and Phase II of
the SHHIRP
--------------------------------------------------------------------------------------------------------------------------------------------------------
Proposed take--phase I Proposed take--phase II Take as percentage of
---------------------------------------------------- stock abundance
Species Stock Level A Level B Level A Level B -------------------------
harassment harassment harassment harassment Phase I Phase II
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gray Whale................................. Eastern North Pacific........ 0 2 0 8 <1 <1
Fin Whale.................................. Northeast Pacific............ 0 16 0 75 * *
Humpback Whale............................. Hawai[revaps]i............... 0 19 0 91 <1 <1
Mexico-N Pacific............. 0 2 0 11 * *
Western N Pacific............ 0 1 0 1 <1 <1
Minke Whale................................ Alaska....................... 0 2 0 8 * *
Killer Whale:
Eastern North Pacific-Alaska 0 20 0 105 1 5.5
Resident.
Eastern North Pacific-Gulf of 0 6 0 32 1 5.5
Alaska, Aleutian Islands,
and Bering Sea Transient.
Pacific White-sided Dolphins............... North Pacific................ 0 10 0 20 <1 <1
Dall's Porpoise............................ Alaska....................... 17 45 28 236 * *
[[Page 12386]]
Harbor Porpoise............................ Gulf of Alaska............... 4 10 7 52 <1 <1
Steller Sea Lion........................... Western...................... 300 5,250 300 25,875 11 52.5
Northern Fur Seal.......................... Eastern Pacific.............. 0 2 0 8 <1 <1
Harbor Seal................................ South Kodiak................. 6 37 13 187 <1 <1
Northern Elephant Seal..................... CA Breeding.................. 0 2 0 8 <1 <1
--------------------------------------------------------------------------------------------------------------------------------------------------------
* a reliable abundance estimate is not available for this stock.
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting the
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks, and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat, 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 City of Kodiak in its adequate and complete application or
are the result of subsequent coordination between NMFS and the City of
Kodiak. City of Kodiak 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 IHAs.
These measures must be adhered to unless in the case of human safety
concerns or pile refusal/instability.
Pre- and Post-Activity Monitoring
Prior to the start of daily in-water construction activities, or
whenever a break in pile driving of 30 minutes or longer occurs, PSOs
would observe for marine mammals at least 30 minutes (pre-clearance
monitoring) through 30 minutes post-completion of pile removal/driving,
DTH drilling, or hydraulic rock hammering activities. Pre-clearance
monitoring must be conducted during periods of visibility sufficient
for the lead PSO to determine that the shutdown zones indicated in
tables 12 and 13 are clear of marine mammals.
Soft-Start Procedures for Impact Driving
Soft-start procedures provide additional protection to marine
mammals by providing warning and/or giving marine mammals a chance to
leave the area prior to the hammer operating at full capacity. The City
of Kodiak must use soft start techniques when impact pile driving. Soft
start requires contractors to provide an initial set of three strikes
at reduced energy, followed by a 30-second waiting period, then two
subsequent reduced-energy strike sets. A soft start must be implemented
at the start of each day's impact pile driving and at any time
following cessation of impact pile driving for a period of 30 minutes
or longer. Soft start is not applicable to other in-water construction
activities.
Clearance and Shutdown Zones
For all pile driving and removal activities, DTH drilling, and
hydraulic rock hammering, the city of Kodiak proposes to implement
clearance and shutdowns. The purpose of a clearance and shutdown is to
reduce the probability or scope of proximal acute impacts by taking
steps in real time (i.e., delay commencement of or stopping an
activity) once a higher-risk scenario is identified Clearance and
shutdown zones vary based on the activity type and marine mammal
hearing group (tables 12 and 13) but are essentially equal with respect
to size. In most cases, these zones are based on the estimated Level A
harassment isopleth distances for each hearing group and rounded up.
The City of Kodiak would implement clearance and shutdown zones that
exceed the calculated Level A harassment zones during the vibratory
installation and removal of all piles during both phases of
construction. During impact driving, DTH drilling, and rock hammering
(the latter of which applies to Phase II exclusively), the City of
Kodiak would implement clearance and shutdown zones with a maximum size
of 400 m for porpoise and harbor seals due to difficulty in observing
these species at greater distances. For Steller sea lions, the city of
Kodiak would implement clearance and shutdown zones with a maximum size
of 50 m for these activities. Given the persistent occurrence of
Steller sea lions in the project area, establishing mitigation zones
beyond 50 m would be impracticable and lead to delays in the project
which could have negative consequences in that the project would be
extended over time. For all other marine mammal species, proposed
clearance and shutdown zones would
[[Page 12387]]
exceed the calculated Level A harassment zones.
Construction supervisors and crews, PSOs, and relevant City of
Kodiak staff must avoid direct physical interaction with marine mammals
during construction activities. If marine mammals come within 10 m of
such activity, operations must cease, to avoid direct interaction. If
an activity is delayed or halted due to the presence of a marine
mammal, the activity may not commence or resume until either the animal
has voluntarily exited and been visually confirmed beyond the clearance
and shutdown zone indicated in tables 12 and 13, or 15 minutes have
passed without re-detection of the animal.
Finally, construction activities must be halted upon observation of
a species for which incidental take is not authorized or a species for
which incidental take has been authorized but the authorized number of
takes has been met entering or within any clearance and shutdown zone.
If a marine mammal species not covered under these IHAs enters a
clearance and shutdown zone, all in-water activities will cease until
the animal leaves the zone or has not been observed for at least 15
minutes. Pile driving will proceed if the unauthorized species is
observed leaving the clearance and shutdown zone or if 15 minutes have
passed since the last observation.
Table 12--Proposed Clearance and Shutdown Zones (m): Phase I
----------------------------------------------------------------------------------------------------------------
Clearance and shutdown zones (m)
----------------------------------------------------------------- Level B
Pile size and material Low High Very high harassment zones
frequency frequency frequency Phocids Otariids (m)
cetaceans cetaceans cetaceans
----------------------------------------------------------------------------------------------------------------
Vibratory pile driving
----------------------------------------------------------------------------------------------------------------
24-inch steel piles \a\..... 20 10 20 30 10 7,360
30-inch steel piles......... 35 15 30 45 15 11,660
----------------------------------------------------------------------------------------------------------------
Impact pile driving
----------------------------------------------------------------------------------------------------------------
24-inch steel piles \b\..... 590 75 400 400 50 1,000
24-inch steel piles......... \c\ 1,940 250 \c\ 400 \c\ 400 50 1,000
30-inch steel............... \c\ 1,940 250 \c\ 400 \c\ 400 50 1,000
----------------------------------------------------------------------------------------------------------------
DTH pile drilling
----------------------------------------------------------------------------------------------------------------
24-inch steel \b\........... 1,430 185 400 400 50 12,000
24-inch steel............... 1,660 215 400 400 50 12,000
30-inch steel............... 3,575 460 400 400 50 12,000
----------------------------------------------------------------------------------------------------------------
\a\ Indicates both temporary and permanent piles.
\b\ Indicates temporary piles only.
\c\ The Level A harassment zone is the largest zone for these hearing groups for these activities and therefore
represents the largest monitoring zone.
Table 13--Proposed Shutdown Zones (m) and Monitoring Zones: Phase II
----------------------------------------------------------------------------------------------------------------
Shutdown zones (m)
----------------------------------------------------------------- Level B
Pile size and material Low High Very high harassment zones
frequency frequency frequency Phocids Otariids (m)
cetaceans cetaceans cetaceans
----------------------------------------------------------------------------------------------------------------
Vibratory pile driving
----------------------------------------------------------------------------------------------------------------
12- to 20-inch piles \a\.... 30 15 25 40 15 7,360
16- or 18-inch steel piles.. 20 10 20 30 10 7,360
20- or 24-inch steel piles.. 20 10 20 30 10 7,360
----------------------------------------------------------------------------------------------------------------
Impact pile driving
----------------------------------------------------------------------------------------------------------------
16- or 18-inch steel piles.. \c\ 1,425 185 \c\ 400 400 \c\ 50 465
24-inch steel piles \b\..... 590 75 400 400 50 1,000
20- or 24-inch steel........ \c\ 1,940 250 \c\ 400 400 50 1,000
----------------------------------------------------------------------------------------------------------------
DTH pile driving
----------------------------------------------------------------------------------------------------------------
16- or 18-inch steel........ 230 30 350 205 50 12,000
24-inch steel piles \b\..... 1,430 185 400 400 50 12,000
20- or 24-inch steel........ 1,660 215 400 400 50 12,000
----------------------------------------------------------------------------------------------------------------
Hydraulic hammering/rock fracturing
----------------------------------------------------------------------------------------------------------------
Rock hammering.............. \c\ 610 80 \c\ 400 400 50 545
----------------------------------------------------------------------------------------------------------------
\a\ Indicate existing piles for removal only.
\b\ Indicate temporary piles only.
\c\ The Level A harassment zone is the largest zone for these hearing groups for these activities and therefore
represents the largest monitoring zone.
[[Page 12388]]
Protected Species Observers (PSOs)
The number and placement of PSOs during all construction activities
(described in the Proposed Monitoring and Reporting section) would be
designed to ensure that the entire shutdown zone is visible. The City
of Kodiak would employ a minimum of three PSOs and all three PSOs would
be on duty during all pile driving, pile removal, and DTH drilling
activities for Phase I and Phase II of the SHHIRP.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined for each proposed IHA that the proposed
mitigation measures provide the means of effecting the least
practicable impact on the affected species or stocks and their habitat,
paying particular attention to rookeries, mating grounds, and areas of
similar significance, 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
<bullet> Mitigation and monitoring effectiveness.
The monitoring and reporting requirements described in the
following were proposed by the City of Kodiak in its adequate and
complete application. The City of Kodiak has agreed that all of the
mitigation measures are appropriate. NMFS describes these below as
proposed requirements and has included them in the proposed IHA's.
All PSOs must be NMFS-approved and have no other assigned tasks
during monitoring periods. At least one PSO would have prior experience
performing the duties of a PSO during construction activity pursuant to
a NMFS-issued ITA.
During all in-water work for Phase I and Phase II of the SHHIRP,
PSOs would monitor from various stations around the project sites (See
figure 16 in the City of Kodiaks Protected Species Monitoring and
Mitigation Plan for station locations). PSOs would monitor the Level A
harassment and Level B harassment zones to the extent practicable
document the marine mammal's presence and behavior. During Phase I in-
water construction, a minimum of three PSOs will monitor for marine
mammals 30-minutes before, during, and 30 minutes after the specified
activities from stations 1, 2, and 3. figure 16 in the City of Kodiak's
Protected Species Monitoring and Mitigation Plan. During Phase II, a
minimum of three PSOs would monitor for marine mammals during pile
driving activities from stations 1, 3, and 4 while a minimum of two
PSOs would monitoring during rock hammering and dredging activities
from stations 3 and 4.
Monitoring would be conducted 30 minutes before, during, and 30
minutes after the specified activities. Prior to the start of daily
activities listed in table 12 and table 13 and again following the
conclusion of these activities each day, PSOs shall conduct a
systematic census of Steller sea lions within the harbor. PSOs will
record the total number of individuals observed hauled out on the float
and those present in the water. To the maximum extent possible, PSOs
shall document and record the identity of any individually identifiable
Steller sea lions (e.g., those with brands, scars, or unique markings).
Additionally, observers would record all incidents of marine mammal
occurrence, regardless of distance from activity, and would document
any behavioral reactions in concert with distance from piles being
driven or removed. Pile driving activities include the time to install
or remove a single pile or series of piles, as long as the time elapsed
between uses of the pile driving equipment is no more than 30 minutes.
The City of Kodiak would abide by all monitoring and reporting
measures contained within the IHAs, if issued, and their Protected
Species Monitoring and Mitigation Plans (see NMFS' website 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>). NMFS describes these
below as requirements and has included them in the proposed IHA.
Reporting
The City of Kodiak would be required to submit a draft report(s) on
all construction activities and marine mammal monitoring results to
NMFS within 90 days of the completion of monitoring, or 60 days prior
to the requested issuance of any subsequent IHAs or similar activity at
the same location, whichever comes first. The information required to
be collected and reported to NMFS is included in the draft IHA
available at <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>. In
summary, the report would include, but not be limited to, information
regarding activities that occurred, marine mammal sighting data, and
whether mitigative actions were taken or could not be taken. The City
of Kodiak would also be required to submit reports on any observed
injured or dead marine mammals. If the death or injury was clearly
caused by the specified activity, the City of Kodiak 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. The City of Kodiak would not resume its activities until notified
by NMFS.
Specific proposed mitigation, monitoring, and reporting
requirements can be found in the draft IHAs found at https://
www.fisheries.noaa.gov/national/marine-mammal-protection/
[[Page 12389]]
incidental-take-authorizations-construction-activities.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the majority of our analysis applies to all
the species listed in table 3, given that many of the anticipated
effects of this project on different marine mammal stocks are expected
to be relatively similar in nature. Where there are meaningful
differences between species or stocks, or groups of species, in
anticipated individual responses to activities, impact of expected take
on the population due to differences in population status, or impacts
on habitat, they are described independently in the analysis below.
NMFS has identified key factors which may be employed to assess the
level of analysis necessary to conclude whether potential impacts
associated with a specified activity should be considered negligible.
These include (but are not limited to) the type and magnitude of
taking, the amount and importance of the available habitat for the
species or stock that is affected, the duration of the anticipated
effect to the species or stock, and the status of the species or stock.
The following factors support negligible impact determinations for all
affected stocks.
Pile driving, pile removal, DTH drilling, and rock hammering
activities associated with both phases of the SHHIRP, as outlined
previously, have the potential to disturb or displace marine mammals.
Specifically, the specified activities may result in take, in the form
of Level B harassment and, for some species, Level A harassment from
underwater sounds generated by impact pile driving, DTH drilling, and
hydraulic rock hammering. Potential takes could occur if individuals
are present in the ensonified zone when these activities are underway.
For Phase I and Phase II of the SHHIRP, take by Level A harassment
is proposed to be authorized for four species (Dall's porpoise, harbor
porpoise, harbor seal, and Steller sea lion) to account for the
possibility that an animal could a Level A harassment zone prior to
detection, and remain within that zone for a duration long enough to
incur AUD INJ. Any take by Level A harassment is expected to arise
from, at most, a small degree of AUD INJ, i.e., minor degradation of
hearing capabilities within regions of hearing that align most
completely with the energy produced by impact pile driving, DTH
drilling, and rock hammering (i.e., the low-frequency region below 2
kilohertz (kHz)), not severe hearing impairment or impairment within
the ranges of greatest hearing sensitivity. Animals would need to be
exposed to higher levels and/or longer duration than are expected to
occur here in order to incur any more than a small degree of AUD INJ.
If hearing impairment occurs, it is most likely that the affected
animal would lose only a few dB in its hearing sensitivity. Due to the
small degree anticipated, any AUD INJ from Level A harassment
potentially incurred is not be expected to impair an individual's
ability to communicate, forage, or detect predators to a level that
would impact reproductive success or survival, much less result in
adverse impacts on the species or stock.
Further, in both Phase I and Phase II, the quantity of take by
Level A harassment proposed for authorization is very low. For eight
species, NMFS anticipates no take by Level A harassment over the
duration of the City of Kodiaks planned activities (both phases). For
Phase I, NMFS expects 17 takes of Dall's porpoise by Level A harassment
and 28 in phase II; 4 takes by Level A harassment for harbor porpoise
in Phase I and 7 in Phase II; and 6 takes by Level A harassment for
[…truncated; see source link]Indexed from Federal Register on March 13, 2026.
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.